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Adsorption Properties of Mahogani (Swietenia Mahogani) Leaf Powder: Removal of Acid Dyes from Aqueous Solution.
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2014-04) Akther, Meghla; Badal, Dr. Md. Mizanur Rahman
The Mahogani (Su'itenic, Mahogani) leaf treated with used as an adsorbent for the sulphuric acid and !'formaldehyde were removal of Reactive yellow C8G and Reactive red MSB de from aqueous solution. The adsorption characteristics of reactive dyes on activated Mahogani leaf powder (MLP) were evaluated as a function of p1-I, adsorbent dose and initial concentration of adsorhate. The amount of dye adsorbed per unit weight of the adsorbent increased with the increase of concentration and contact time. The adsorption was favored by an acidic p1-I range for Reactive red but not significant change for reactive yellow dyes. The adsorption processes were best described by a second-order rate equation. Reactive Yellow and Reactive Red dyes adsorption on MLP agreed with both Langmuir and Freundlich isotherms. The isotherm plots showed that the Freundlich equation gave slightly better linearity than the l.angmuir equation (R 0.94 for Langmuir plots; R 0.99 for Freundlich plots) indicating the MLP surfoce to be heterogeneous in the long range, but having some amount of uniformity locally. Langmuir monolayer adsorption capacity ((1ni) decreased from 67.11 to 11 .93 mg/g br reactive vehlo\v and from 12.39 to 2.09 mg/g for reactive red. MLP amount varying from 0.5 to 1.0 g/L. Ihe adsorption equilibrium parameter, for reactive yellow. h. varied from 0.028 to 0.034 L!mg with the increase in MLP amount and similar trend observed for reactive red. 'l'he adsorption capacity, k fshowed a decrease from 143.52 to 19.76 L/g with increase in MLP amount Irom 0.5 to 1.0 g/L, Similar results found for reactive red dye. The adsorption affinity. 11. lies between 0.21 and 0.27 satisfying the condition a < I for favorable adsorption.
Effect of N-Acetylcysteine on Volumetric and Viscometric Properties of Chitosan in Aqueous Acidic Solution
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2017-12-31) Kashem, Md. Abul; Yousuf, Prof. Dr. Mohammad Abu
Volumetric and viscometric studies of Chitosan-H20-CH3COOH and NAC (NAcetylcysteine)-Chitosan-[H20-CH3COOH] systems were investigated at 298.15 to 323.15 K at 5 K intervals. In a]l investigated systems concentrations of NAC were 0.10,0.50 & 1.00 mol.L' and concentrations of chitosan were 0.003, 0.006 & 0.012 mol.L* H20-CH3COOH mixed solvent was used for the experiment and H20 to CH3COOH ratios 9:1, 7:3 and 3:2 were maintained. Densities have been found to be increased with increasing concentration of both NAC and chitosan but decreased with increasing temperature. Densities were found to be increased with increasing the ratio of CH3COOH in Chitosan-H20-CH3COOH systems but this trend was not so significant is case of NAC-Chitosan-H20-CH3COOH systems. Density Values of NAC-Chitosan-[H20-CH3COOH] systems were remarkably higher than those Chitosan-H20-CH3COOH systems.The apparent molar volumes, φv of both Chitosan-H20-CH3COOH and NACChitosan-H20-CH3COOH systems were determined from the experimental density values data at 298.15 to 323.15 K at 5 intervals. The φv values were dependent upon concentration of NAC and chitosan in mixed solvents as well as the temperature. φv values have been found to be positive in all investigated systems. The φv values decreased throughout the whole concentration range for NAC and chitosan in their specific solvent systems. These results may be due to the solute—solvent, and solute—solute interaction through dipole-dipole interaction, ion-dipole interaction, hydrogen bond, hydrophilic or hydrophobic interaction among NAC, chitosan and aqueous acetic acid in the solutions. Besides, φv values were found to be increased with increasing temperature at any concentration of NAC and chitosan in solutions and this is may be due to increased thermal agitation at higher temperatures. Apparent molar volume at infinite dilution, φvo; apparent molar expansivity and Sv values were also determined. The φvo; values of chitosan-[H20-CH3COOH] systems decreased with increasing temperatures and increased with increasing the ratio of CH3COOH in H20-CH3COOH mixed solutions. At elevated temperatures cages in the investigated systems becomes less important hence the apparent molar volume at infinite dilution, φv3 decreased with increasing temperature. in addition, incorporation of more acetic acid ratio in Chitosan-H20-CH3COOH system hydrophobic-hydrophobic repulsion predominant over hydrogen bonding or dipole-dipoleinteraction. The apparent molar volume at infinite dilution gives an idea about the presence of solute—solvent interactions. The expansivity values are positive at all the investigated temperatures. Positive values indicate that, on heating some NAC and chitosan molecules may be released from the solvation layer of ion. It may also be conferred that the positive φEo;values may be originated from the hydrophobic character and steric effect of the NAC and chitosan in systems. As a whole there is a hydrophilic/hydrophobic balance among the solute and solvent molecules. S parameters contribute an idea about the prevailing solute—solute interactions in the mixtures. The negative and large in magnitude values of Sv in all investigated systems supports the weak solute-solute interaction present. Both Chitosan-H20-CHICOOH and NAC-Cli itosan-H20-CH3COOH systems showed rapid increase of viscosity values with the increase of chitosan and NAC concentrations but viscosities decreased with the increase of temperature. The increase of η values of with concentration of chitosan and NAC can be attributed to the increase in solute—solvent, and solute—solute interactions in solution. The small range of dissolution of chitosan and/or NAC in H2 0-Cl-13C00H might have intriguing aspects which may be the consequence of the great ability of H20 and Cl-13C00H to make hydrogen bond and dipole-dipole, ion-dipole interaction. In all cases with the increase of temperature internal energy of the systems increased as a result solute-solute or solute-solvent interaction may be depleted and viscosity values decreased. The viscosity data were employed to determine A and B-coefficients; change of free energy, ∆G*; change of enthalpy. ∆H* and change of entropy,∆*. From these thermodynamic parameters state of the spontaneity of the investigated systems were known. Besides, negative A and positive B co-efficient suggesting that weak solute solute but strong solute-solvent interaction present. The change of free energy values for viscous flow,∆G* were found to be positive indicate that work has to be done to overcome the energy barrier for the flow process. The positive AH values indicate that work has to be done for all the investigated systems. The ∆S* values are negative for all the systems studied. This means that Chitosan-[H20-GH3COOH] and NACChitosan-[H20-CH3COOH]systems are regular than those of the pure one. Here one point may be remarked that as ∆S < 0 and ∆H> 0, so the processes are never spontaneous but the reverse process is always spontaneous.
Effect of Surfactant on Formation of Hydroxyapatite under Reverse Micelle Condition
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2018-12-23) Yeasmin, Fargana; Yousuf, Prof. Dr. Mohammad Abu
Hydroxyapatite, (HAp), Ca10(PO4)6(OH)2, is a naturally occurring material found in the inorganic component of human bone and enamel. The constituent elements of HAp are primarily calcium and phosphorous, with a stoichiometric calcium to phosphorous ratio is 1.667 capable of promoting intimate bone growth onto femoral implants. The performance, lifespan and quality of the resultant biological coating in vivo is largely dependent on the coating morphology, phase composition, particle size and crystallinity of the powders pre-coating application. The present study focused on preparing Hydroxyapatite nanoparticles (HAp-NPs) through chemical precipitation technique using mixed micelle core as a nanoreactor. Mixed micelle core was used to control morphology such as crystallinity, particle size, particle shape, particle size. Anionic (sodium dodecyl sulphate (SOS)) and cationic (Cetyl trimethyl ammonium bromide (CTAB)) surfactants were used to prepare the mixed micellar core. 18 : 2 ratio of propanol-1 : water system experimentally selected for the formation of reverse micelle for the afore mentioned surfactants. Compositions of both surfactants were varied to control the morphology of HAp-NPs under the same experimental condition. Several techniques such as FTIR, XRD, TOA and SEM were used to characterize the prepared HAp-NPs. Appearance of peaks at various position of the FTIR spectrum shows the PO vibrations of PO;- which are characteristics of hydroxyapatite. In addition, the diffraction pattern of the prepared HAp-NPs are in well agreement with the standard published by the International Centre for Diffraction Data. However, the diffractogram indicates the presence of crystalline as well as amorphous phase. No significant weight loss was observed for the prepared HAp-NPs. SEM result reveals significant morphological variation of the prepared HAp-NPs by changing the amount of two surfactants. Variation of the ratio of surfactants SOS and CT AB allow the variation in the morphology of the prepared particles.
Electrochemical Characterization Of Biologically Important Electroactive Metal Ligand Complexes With Multi-electron Transfer Reactio
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2014-07) Rahman, Md. Matiar; Motin, Prof. Dr. Md. Abdul
The redox behavior of Cu (II) only and Cu (II) with aspartic acid (Apa), L-phenl alanine (Phe), 3-nitrobenzene sulfnate (NBS) ; Zn(II) only and Zn(ll) with Apa, Phe, NBS and Catechol ((ate) has been studied Cyclic voltammetry (CV), Differential pulse voltammetry (DPV) and Chronamperometry (CA) techniques. The voltammetri technique demonstrates the interaction of biologically important metals (Cu, Zn) with the ligands (Apa, Phe, NBS, Cate) that is formed of metal-ligand complexes. The interaction studies have been carried out in variation of metal ion concentration, ligand concentration, Buffer solution of different pH and scan rate. In all the studies of Cu(II) and Zn(II) complexes, with some exception, Cu(II )-ligand systems and Zn(II)-ligand systems have been found to undergo quasireversible electrode reaction with EC mechanism. For all the ligands, Apa and Phe are electroinactive ligands whereas Cate and NBS are electroactive ligands. Both the anodic and cathodic voltamnietric peaks were shifted and sometimes developed new peaks with the addition of Apa, Phe, NBS, Cate in Cu(II) and Zn(II) solutions. On the addition of Apa, Phe and NBS in Cu(II) solution, the peak positions of the voltammogram of Cu(II)-Apa, Cu(II)-Phe and Cu(II)-NBS, first anodic peak was shifted positively but the second oxidation peak was shifted negatively with respect to that of only Cu ( II). The peak current decreases significantly compared with that for free Cu(II) in the same experimental conditions, This behavior confirms the interaction and complexation between Cu(II) and Apa, Phe. The effect of pH of Cu(II)-Apa, Cu(II)-Phe and Cu(II)-NBS were studied by varying pH from 3.5 to 7.0. The peak current of Cu(II)-Apa, Cu (II)-Phe and Cu(II)-NBS increases with the decrease of pH indicating that at lower pH the Cu(II)-Apa, Cu(II)-Phe and Cu(II)-NBS is highly electroactive. The maximum peak current was obtained at pH 3.5. This shows that the electrochemical oxidation of Cu(II)-Apa, Cu(II)-Phe and Cu(II)-NBS is aicilitated in acid media and hence the rate of electron transfer is faster.The average diffusion coefficient, D of Cu(II)- Apa or Cu(II)-Phe is found to he 4.5 x l0-6cm2s-1. The cyclic voltammogram of Zn(II) only and Zn(II) with Apa, Phe, NBS and Cate in aqueous and in buffer solution of different pH were taken at different scan rates. The CV of Zn (II) shows at pH (1 .5, 3 and 4.5) one well defined anodic and cathodic peak at different scan rate hut in aqueous solution only Zn(II) showed very weak anodic peak. Upon the addition of Apa, Phe, NBS, Cate with Zn(II) the first anodic peak shifted positively and the cathodic peak is shifted negatively which indicates the formation of Zn (II)-Apa or Zn ( II)- Phe complex. The intensity of the anodic and cathodic peak current decreases with the increasing of Apa or Phe or NBS or Cate suggesting that is formed of more Zn( 11 )-Apa or Zn(II)- Phe or n(ll)- NBS complex. The effect of pH of Zn(II)-Apa, Zn(II)-Phe, Zn(II)-N BS and Zn(II)-Cate were studied by varying pH from 1.5 to 11. The peak current decreases with the increase of pH .The maximum peak current was obtained at pH 3-4.5.At higher pH(7-11), the anodic peak disappeared. This shos that the electrochemical oxidation of Zn(II) complexes is hindered in basic media. For the comparison CV of Zn(II) only and Zn( II) —Asp, Zn(II)-Phe, Zn( II)- Cate, Zn( II)-NBS at similar condition (pH 3, scan rate 0.1 V/s). it is seen that the anodic peak current of Zn(II)-Asp and Zn(II)-Phe are lower than that of Zn(II) only hereas the anodic peak current of Zn(II) - Cate and Zn(II)-NBS is higher than that of Zn(II) only. When Cate and NBS are coordinated with Zn(II) both metal and ligands are electroactive, So constructive interference of peak appeared whereas Asp and Phe are coordinated with Zn(II), here ligands are eleciroinactive so the overall peak currents are lower than Zn(II) only. The slopes of the plots of Ep against pH of all studied metal ligand complexes ere determined graphically as anodic peak 25- 35 mV/pH at 0.1 V/s, which is close to the theoretical value of 30 mV for a two-electron, two-proton transfer process which indicates that the oxidation of all metal-ligand complexes proceeded via the 2e-2H+ processes. This suggests that during the reaction not only electron but also protons are released from the metal-ligand complexes. For all the studied system, with the increasing of metal: ligand composition from 1:1 to 1:5 (metal fixed), the current decreases linearly but after more addition of ligands, the current intensity change is constant. This indicates that the availability of metal is limited for the formation of the metal-ligand complex at saturation point. When the composition of metal increases with the fixed of the composition of ligands from 1:1 to 5:1. after certain concentration, the voltammogram pattern reflected into the only metal, because of the deficiency, of ligands in solution. The relation between metal - ligand concentration and cyclic voltammetric anodic and cathodic peak current (Ipaand Ipc) is linear. The proportionality of the anodic and cathodic peak currents with square root of scan rate of all the studied metal ligand complexes with few exceptions suggests that the peak current of the difièrent complexes at each redox reaction is controlled by diffusion process. From the studied of all systems it is seen that current functions (1/v-1/2) decreased with the increasing of' scan rate except Zn(II)- Cate. So the behavior of electrode reaction of all Cu(II)- ligands and Zn(II)- ligands are of ECE mechanism except Zn(II)- Cate is of CE mechanism.
Electrochemical Characterization of Some Electroactive Nucleophilic Substitution Reactions
(Khulna University of Engineering & Technology (KUET), 2016-07) Islam, Md. Rabiul; Motin, Dr. Md. Abdul
The substitution reaction of Catechol in presence of Imidazole, L-Arginine and L-Serine have been studied by cyclic voltammetry, controlled potential coulometry and differential pulse voltammetry techniques using Glassy carbon (GC), Gold (Au) and Platinum (Pt) electrodes. The voltammetric studies have been carried out by varying the composition of Catechol, Imidazole, L-Arginine and L-Serine in the buffer solution of different pH, different electrodes and scan rate. Pure Imidazole, L-Arginine and L-Serine are electro-inactive whereas pure Catechol is electro-active. In the second scan of potential, a new anodic peak appears at the lower potential and the oxidation and reduction peak shifted with respect of pure catechol after addition of Imidazole, L- Arginine and L-Serine in catechol solution. At the same time the anodic and cathodic peak current decreases significantly compared with the pure catechol that indicates the participation of reaction of o-benzoquinone with Imidazole, L-Arginine and L-Serine. The reaction products generated from the reaction of catechol in presence of Imidazole, L-Arginine and L-Serine are assumed to be 4-(1H-imidazol-1-yl)cyclohexa- 3,5-diene-1,2-dione- 2-amino-4-(1-(3,4-dioxocyclo hexa-1,5-dien-1-yl)guanidino)-4- oxobutanoic acid and 3-hydroxy-2-((3-hydroxy-4-oxocyclohexa-2,5-dien-1- ylidene)amine)propanoic acid respectively that undergo electron transfer at more negative potentials than the Catechol. The electro –synthesized products generated from Catechol with Imidazole, L-Arginine and L-Serine were isolated. The formation of Catechol-nucleophile adducts are also confirmed by FTIR spectra. The pH effect of catechol in presence of Imidazole, L-Arginine and L-Serine has been investigated in different pH from 3 to 11. From the experiment it has been observed that almost no new anodic peak appeared after repetitive cycling at pH 3-5 (acidic media) and pH 9-11 (basic media). At pH 7, the o-benzoquinone undergoes nucleophilic attack by the amines that is reflected from voltammetric new anodic peak, A0 appeared after repetitive cycling. The slopes of the peak potential, Ep vs pH plot has determined graphically as the anodic peaks of Catechol-Imidazole (60 mV/pH), Catechol-Arginine (56mV/pH) and Catechol-Serine (61.5 mV/pH) at 0.1V/s.
Investigation of Removal Characteristics of Heavy Metal Ions by Natural Adsorbents
(2011-12) Golder, Harabilash; Yousuf, Professor Dr. Mohammad Abu
Rice husk, which is a relatively abundant and inexpensive material, is currently being used as the source of activated carbon an adsorbent for the removal of various pollutants from water. Activated carbon was prepared and characterized from rice husk. Rice husk was collected from local rice mill and used as raw material for producing activated carbon. Low-cost furnace was designed from locally available pottery and very slow burning of rice husk in presence of insufficient oxygen was applied for the preparation of activated carbon. The carbonized temperature and time was 350-550 C and about 3.0 hours respectively. The percentage of the yield in this method is about 25 (wt) %. Prepared activated carbon was characterized by a series of' experiments such as ash content, volatile content, moisture content, fixed carbon content, porosity and adsorption study. The prepared activated carbons contain 39.47% ash and 35.98% fixed carbon. SEM photographs exhibit that the prepared activated carbon possesses significant number of micropores, mesopores and macrospores. XRD analysis provides information that the prepared samples are amorphous in nature. All these observed properties indicate that the prepared samples might be used as good adsorbent.SEM photograph before and after adsorption clearly showed the evidence in favor adsorption. Prepared activated carbon used as potential adsorbent for methylene blue.Pb2+and Hg2+ in aqueous solution. Methylene blue showed maximum adsorption at pH 6.0. With increasing the sizes of adsorbents the extent of adsorption decreased at two investigated temperatures, 30 °C and 40 T. The equilibrium time for the adsorption was found to be about 180 minutes. Under all conditions amount of adsorbed increased with increasing the concentration of adsorbates. The experimental data have been found to be fit into Freundlich adsorption isotherm suggesting the chemisorption occurred. Both Pb2+and Hg2+ in aqueous solution showed maximum adsorption at pH 5.7 and 150 Rev/min shaking frequency. The equilibrium time for the adsorption in both cases were found to be about 180 minutes under all conditions and the amount of' adsorption increased with increasing the concentration of adsorbates. The experimental data have been found to be fit into Freundlich adsorption isotherm suggesting the chemisorptions occurred.
Investigation Of Removal Characteristics Of Heavy Metal Ions By Natural Adsorbents
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2011-12) Golder, Harabilash; Yousuf, Prof.Dr. Mohammad Abu
Rice husk. which is a relatively abundant and inexpensive material, is currently being used as the source of activated carbon an adsorbent for the removal of various pollutants from water. Activated carbon was prepared and characterized from rice husk. Rice husk was collected from local rice mill and used as raw material for producing activated carbon. Low-cost furnace was designed from locally available pottery and very slo burning of rice husk in presence of insufficient oxygen was applied for the preparation of activated carbon. The carbonized temperature and time was 350-550 C and about 3.0 hours respectively. The percentage of the yield in this method is about 25 (wt) Prepared activated carbon was characterized by a series of' experiments such as. ash content, volatile content. Moisture content, fixed carbon content. porosity and adsorption study. The prepared activated carbons contain 39.47% ash and 35.98% fixed carbon. SEM photographs exhibit that the prepared activated carbon possess significant number of microspores. mesopores and macrospores. XRD analysis provides information that the prepared samples are amorphous in nature. All these observed properties indicate that the prepared samples might be used as good adsorbent. SEM Photograph before and after adsorption clearly showed the evidence in favor adsorption. Prepared activated carbon used as potential adsorbent for methylene blue. Pb2+and Hg2+ in aqueous solution. Methylene blue showed maximum adsorption at pH 6.0. With increasing the sizes of adsorbents the extent of adsorption decreased at two investigated temperatures, 30 °C and 40 T. The equilibrium time for the adsorption tas found to be about 180 minutes. Under all conditions amount of adsorbed increased with increasing the concentration of adsorbates. The experimental data have been found to be fit into FreundIich adsorption isotherm suggesting the chemisorption occurred. Both Pb2+ and Hg2+ in aqueous solution showed maximum adsorption at p1-I 5.7 and 150 rev!miii shaking frequency. The equilibrium time for the adsorption in both cases were found to be about 180 minutes under all conditions and the amount of' adsorption increased with increasing the concentration of adsorbates. The experimental data have been found to be fit into Freundlich adsorption isotherm suggesting the chemisorption occurred.
Physico-Chemical Studies Of Different Solutions Of Electrolytes NH4C1, FeC13 and NiC12) IN Mixed Solvents (Water-DMSO)
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2008-08) Reza, K. M. Salim; Prof. Dr. Md. Abdul Aziz
The volumetric, viscometric and some other related properties of DMSO in aqueous solutions and some electrolytes such as NH4C1, NiC12 and FeCl3 in water, DMSO and mixed solvents have been measured. The apparent molal volumes, and viscosities, of NH4Cl,NiC12 and FeCl3 in water and water-DMSO solutions were studied as a function of concentration at a wide range of temperatures of 288, 293, 298, 303, 308 and 313 K. The apparent molal volumes at infinite dilutions (limiting apparent molal volume) of these values to the zero concentrations which is practically equal to the partial molal volume. Limiting apparent molal volume for all the three electrolytes were determined by extrapolating co electrolytes studied showed higher values in aqueous DMSO solution then those in aqueous solution in the temperature range of 288 K to 313 K. Apparent molal volumes, , is depended upon the electrolyte concentration as well as on the temperature. Apparent molal volumes showed the gradual decrease of volume with concentration except FeCl3 in water and in pure DMSO solution. The value of viscosities increase in molality of the electrolytes except NH4Cl. No significant change of viscosity observed for NH4Cl with increase in molality in aqueous and in 20% aqueous-DMSO solutions. The viscosities, il for all the studied electrolytes are greater in aqueous DMSO solvent system than those in water system alone indicating that electrolytes in aqueous DMSO systems are more structural than those in aqueous system.Viscosity coefficients (A and B) for the above systems were also determined for the Jones Dole equation. B values for NiC12 and FeCl3 were found to be positive that indicate these electrolytes exhibit structure making behavior in water and in water-DMSO solutions. The B value is negative in water and water-DMSO for NH4C1.This indicates that NH4Cl salt behaves as a water structure breaker in aqueous and aqueous DMSO system. The coefficient A represents the solute-solute interactions coupled with size and shape effect of the solute and to some extent solute-solvent interactions. A coefficient was obtained with an irregular variation. The behaviors of three solutes in binary and ternary systems were discussed in terms of the charge, size and hydrogen bonding effect.
Preparation and Characterization of Alkylcarboxylate-Stabilized-Magnesium Nanoparticles
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2011-10) Rahman, Md. Hafizur; Yousuf, Prof. Dr. Muhammad Abu
Long chain carboxylate shell stabilized magnesium (Mg) nanoparticles (NPs) were synthesized. In the core-shell type NPs the cores are Mg metal and the shells are long chain carboxylates. Synthesis of magnesium nanoparticles (Mg-NPs) involve: i) preparation of water soluble Na-salts of long chain fatty acids in alcoholic medium followed by ii) temperature controlled reaction with magnesium salts in aqueous medium in presence of suitable surfactant, poly vinyl pyrrolidone (PVP). The synthesis procedure used in this work was originally applied for the fabrication of long chain carboxylate capped magnesium nanoparticles. Structural and geometrical probabilities of prepared NPs were proposed on the basis of evidences from elemental analysis, optical and spectral studies. The compositions of the NPs were determined by elemental analysis. The experimental and calculated data for carbon (C), hydrogen (H), oxygen (0) and metal were compared. The presence and percentages of C, H and 0 revealed the presence of alkyl carboxylates and is proposed that these alkyl carboxylates act as protected shefls to the Mg-N Ps. From the titration of magnesium laurate, magnesium myristate, magnesium palmitate and magnesium stearate 7.83%, 7.02%, 6.54% and 5.93% Mg were found respectively. These values show that all the substances contain relatively higher amount of Mg than those of the molar ratio. These results exposed metallic Mg in the samples. It is proposed that this metallic Mg may be positioned at the core of the NPs. Melting point (MP) data also provide auspicious evidence about the formation of Mg-NPs. The Fourier Transform Infrared Spectroscopy (FTIR) spectra provide information about the presence of moisture or adhering free water and/or crystalline water and alkyl carboxylates in the NPs. Broad peak at —3040 to 3520 cm 1 appears due to 0-H stretching vibrations of hydroxyl (—OH) group. This may be due to the presence of moisture absorbed by the sample or water of crystallization. Two characteristic peaks at —1510 to 1600 cm 1 and at —1400 to 1510 cm1 were found and these may be due to C=O stretching and C-O stretching of carboxylates respectively. V Transmission Electron Microscopy (TEM) photographs showed the particles have the dimensions over a range of 25-90 nm. At higher magnifications, the NPs were recognized as spherical or oval in shape in all cases. The NPs are hygroscopic in nature as they absorbed 8.54-12.22% moisture. The moistures and/or crystallized water are also evidenced by the Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA) of the respective NPs. Both DTA and TGA demonstrated the presence of alkyl carboxylates or organic part in the NPs. The loss of organic parts at higher temperatures also corresponds to the decomposition of the NPs at higher temperature in a normal furnace as investigated by FTIR analysis.
Preparation and characterization of chitosan based metal nanoparticles and study of their antibacterial property
(Khulna University of Engineering & Technology (KUET), 2016-08) Islam, Gazi Jahirul; Yousuf, Dr. Mohammad Abu
Chitosan is a natural polysaccharide and has significant biological and chemical properties such as biodegradability, biocompatibility, bioactivity, microbial activity and polycationicity. In this research, chitosan based nanoparticles have been prepared for bacteriological application. Chitosan has been prepared and characterized from locally available waste shrimp shell. Prepared chitosan have been used as the raw material for the production of chitosan based metal nanoparticles such as Chitosan based zinc nanoparticle (Chi-Zn NPs), Chitosan based copper nanoparticle (Chi-Cu NPs) and Chitosan based cadmium nanoparticle (Chi-Cd NPs). First chitin has been has been isolated from shrimp shell by demineralization and deproteinization followed by deacetylation to get chitosan. Purity and characteristics of chitosan isolated from shrimp shell has been compared with those of extra pure chitosan purchased from Sisco Research Laboratories (SRL) Private Limited, India. It was characterized by Fourier Transform Infra Red (FTIR) Spectroscopy, solubility, moisture and ash content. It has been found that moisture and ash content of prepared chitosan is 1.25%, 1.22% respectively while those for purchased extra pure chitosan is 1.24% and 1.19%. Both are readily soluble in 1% acetic acid and produce transparent viscous solution. FTIR result of the extracted chitosan is very much comparable to the standard one. It has been seen that there is an excellent agreement between extracted and purchased chitosan. Chitosan based metal nanoparticles have been synthesizes by solution casting method. But the techniques and conditions are different from previous studies [83, 84]. The synthesized NPs were characterized by using FTIR, TGA and SEM analysis. FTIR spectra of the NPs (except Chi-Cd) are very similar to those of the synthesized chitosan. This indicates the presence of chitosan polymer in the NPs matrices. The loss of mass in TG analysis also confirms the presence of chitosan polymer in the Chi-Zn NPs. SEM photograph clearly showed the synthesized materials are nanomaterials within the range of 1-100 nm. Produced NPs exhibited enhanced antibacterial activities. Zone of inhibition against Pseudomonas aeruginosa, Salmonella bovismorbificans, Salmonella typhi and Escherichia coli bacteria of Chi-Zn, Chi-Cu, Chi-Cu(II) and Chi-Cd NPs are 38, 31, 30 and 39 mm; 32, 36, 37 and 32 mm; 30, 35, 36 and 33 mm and 35, 31, 31 and 38 mm respectively, while those for standard drug kanamycin are 22, 22, 20 and 20 mm respectively.
Studies on Chemical Effect and Feasibility of Biosensor for Arsenic Detection in Water.
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2011-06) Parveen, Shahnaz; Yousuf, Prof. Dr. Muhammad Abu
220 water samples of different Arsenic (As) -affected areas in Bangladesh have been collected for analysis. Of them 58 samples were from Sagordari village of Jessore. 53 from Koyra village of Kolaroa, 56 from Hajigong village of Chandpur and 53 from Arihazar village of Narayangonj district. Various water quality parameters such as, p1-I, conductivity, chloride, iron content, hardness and dissolved oxygen were analyzed using standard analytical techniques. The suitability of investigated water for drinking and other purposes was also analyzed comparing with standard values. As content for the 220 different water samples have been perceived in there different methods, i.e., Merck field test kit, ARSOlux biosensor and ICP-MS methods. To find out an easy, low cost and environmentally friendly method for As content in ground water three different methods have been adopted. A comparison has been made among the three different test methods. Effect of different water quality parameters on As test methods has been analyzed. The p1-I range has been found to 6.2-8.1. It is seen that most of the samples i.e., 88.6% are alkaline while those of 10.5% are acidic and only 0.9% are neutral in nature. It is seen that only 4.5% samples have conductivity values with in the limit of drinking water range. Rest of the samples has high conductivity values. Of which 78.6% samples have the conductivity (cy) values of 0.5
Studies on Low cost Bio-Adsorbent in Wastewater Treatment
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2018-05) Amin, Md. Ruhul; Yousuf, Prof. Dr. Mohammed Abu
Environmental pollution is a great concern in now a day. In modern time, with civilization and industrialization environmental pollution increases. Effluents of textile and dyeing industries pollute the environment directly and indirectly as well. Adsorption is one of the versatile techniques of removing waste. In the present investigation LBS Lima Bean Seed (LBS) (locally known as Rukuri in northern zone of Bangladesh) powder has been used as adsorbent for the removal of three textile reactive dyes, namely Reactive Magenta HB (RMHB), Active Orange P2R (AOP2R) and Reactive Red ME6BL (RRME6BL). It is observed that removal efficiency of RMHB, AOP2R and RRME6BL is high at lower pH (acidic medium). Though AOP2R and RRME6BL adsorbed at pH 2.0 and pH 3.0 respectively but in case of RMHB, it adsorbed relatively at higher pH, 6.0. Effect of concentration, adsorbent dose and contact time on adsorption process was observed. Removal of dyes increases with amount of adsorbent and time. But at in case of lower initial dye concentration dye removal rate was faster. Equilibrium time for the adsorption process was about 120 min. From the isotherm study it is observed that the applicability of the linear form of Langmuir and Freundlich model to LBS was confirmed by the high correlation coefficient R2 > 0.97. This suggests that the Langmuir isotherm and Freundlich models both provide good model of the sorption system. The value of 1/n was lower than 1, (n is greater than 1) indicating that studied dyes were favorably adsorbed by LBS. During the kinetics study it is seen that the plot of pseudo-first order has a high correlation coefficient than the plot of pseudo-second order. It should be mentioned, in both cases the value of R2 is close to the unity. More over the values of amount of adsorbate at equilibrium, qe dramatically differ from the experimental values in case of pseudo-second order. So, the adsorption of tested dyes on LBS is more appropriately followed the pseudofirst order model when compared with that of the pseudo-second order model. Study of Intraparticle diffusion model suggested that Intraparticle diffusion is not only Solo Rate Limiting Step.
Studies on the Application of Antibiotics as External Preservatives of Mango Cultivar of Fazli
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2015-06) Khondokar, Md. Arifuzzaman; Morshed, Prof. Dr. Mohammad Hasan
The application of various antibiotics at different concentrations (10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 ppm) for the extension of storage life and quality of fazli mango was studied. The physical properties such as appearance, colour, flavor, taste and texture of all antibiotics treated mangoes were more attractive than those of control one. The storage life of treated mango was prolonged significantly as compared to that of control one. The weight loss control capacity of antibiotics treated mango at 20 ppm of etracycline, amoxicillin 50 ppm, co-trimoxazole 20 and 30 ppm, cefradine 50 ppm, zithromycin 20 ppm was higher than that from control mango. The superior treatment tetracycline 20 ppm, co-trymoxazole 20 & 30 ppm and cefradin 50 ppm reduced the physiological loss in weight 15.79% to 33.62% with respect to control at 14th day. But at 15th day the treatments tetracycline 20 ppm, co-trymoxazole 20 ppm and cefradin 50 ppm reduced the physiological loss in weight 29.34% to 34.33% with respect to control mango. The nutritional qualities of mango were also affected remarkably after treatment with antibiotics. At the last edible stage chemical analysis of mango pulp from antibiotics treated mango at tetracycline 20 ppm, amoxicillin 50 ppm, co-trymoxazole 20 and 30 ppm, ciprofloxacin 20 ppm, cefradin 30 ppm, azithrornycin 20 ppm, cefixime 20 and 30 ppm showed higher pH (5.25, 5.25, 6.20, 6.25, 6.15, 6.32, 5.65, 6.31 and 5.24), total soluble solids (TSS) (12.0%, 11.5%, 15.0%, 19.0%, 18.5%, 17.0%, 15.0%, 14.0% and 13.5%), total sugar (9.79, 6.59, 8.96, 9.77, 11.53, 9.99, 12.39, 9.80 and 10.32 g/100g), protein (0.79%, 1.03%, 0.38%, 0.54%, 0.49%, 0.39%, 0.46%, 0.60% and 0.50%), and iron ( 0.9344, 1.0529, 0.4602, 0.6204, 0.4010, 0.7858, 1.2985, 0.6909 and 0.7572 mg/100g) in comparison to control mango (pH = 5.19, TSS = 10%, total sugar = 10.9 g/l00g, protein = 0.57% and iron = 0.7218 mg/100g). In comparison to control mango it is evident that the antibiotic treated mangoes might be in superior quality as it contains higher vitamin A, vitamin C, total soluble solids, total sugar, iron (Fe) and pH than those of control one.
Studies on the Extension of Shelf life of Selected Type of Mangos
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2015-11) Murshed, Md. Mizanur; Morshed, Prof. Dr. Mohammad Hasan
The application of different types of cost effective preservatives such as tetracycline, sodium benzoate, acetic acid and glycerine at various concentrations for the extension of, shelf lives of Himsagar and Langra mangoes were studied. The physical characters such as appearance, colour, flavour, taste and texture of' treated mango were more attractive than those of control one. The shelf life of, treated mango was prolonged significantly as conipared to that of control one. The weight loss control capacity of preservatives treated mangoes was higher than that from control at 500 ppm of' tetracycline, 80 ppm of sodium benzoate and 100 ppm of acetic acid for Himsagar mango and 10 ppm of tetracycline, 100 ppm of sodium benzoate and 100 ppm of acetic acid lhr I angra cultivar. The superior treatment tetracycline 500 ppm, sodium benzoate 80 ppm and acetic acid 100 ppm of Himsagar cultivar reduced the physiological loss in weight 15.79% to 33.62% with respect to control at 7th day. But at 8th day, the treatments, tetracycline 500 ppm, sodi urn benzoate 80 ppm and acetic acid 100 ppm reduced the physiological loss in weight 35.34% to 40.33% with respect to control mango. On the other hand the superior treatments tetracycline 10 ppm, sodium benioate 100 ppm and acetic acid 100 ppm of Langra mango reduced the physiological loss in weight 17.31% to 29.23% with respect to control at 9thday. The treatments, tetracycline 10 ppm sodium benzoate 100 ppm and acetic acid 100 ppm reduced the physiological loss in weight 31.65 % to 41.53% with respect to control mango, cultivar of' Langra at the 9th day. The efficiency of' glycerine as preservative of Himsagar and Langra mango was not more effective than the other preservatives. The nutritional qualities of mango were also affected remarkably after treatment with preservatives. At the last edible stage, chemical analysis of mango pulp of preservatives treated Himsagar mango at tetracycline 500 ppm, sodium benzoate 80 ppm and acetic acid 100 ppm showed higher pH(5.56, 5.73 and 5.22), TSS (15%, 16% and 18%), total sugar (22.24, 23.53 and 23.30 g/100g), iron (6.7327, 2.5959 and 1.6789 mg/100g), vitamin C ( 20.05. 21.61 and 20.35 mg/100g) and protein (1 .53%, 0.60% and 2.90%) in comparison to control mango (pH 5.19, TSS = 100%, total sugar = 18.60 g/l 00g, iron = 0.7218 mg/I 00g, vitamin C 19.20 mg/100g and protein = 0.57%). The treatments, tetracycline 10 ppm, sodium benzoate 100 ppm and acetic acid 100 ppm showed higher pH (5.19, 5.21 and 5.25), TSS (16%. 14% and 17%), total sugar (11.31, 12.42 and 11.38 g/100g), iron (3.3852, 3.3079 and 4.9801 mg/100g), vitamin C (17.32, 17.81 and 18.09 mg/100g) and protein (2.35%. 3.22% and 1.85%) for cultivar of Langra in comparison to control mango (pH 5.19. TSS = 10%, total sugar 9.04 g/loog, iron = 0.7118 mg/100g, vitamin C = 16.21 mg/l00g and protein = 0.55%). In comparison to control mango it is evident that the preservatives treated mangoes might be in superior quality as it contains higher vitamins, total soluble solids. total sugar. protein. iron and pH than those of control.
Studies on Volumetric and Viscometric Properties of Nitrobenzene and Alkanols Mixtures
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2015-12) Islam, A.K.M. Nasimul; Motin, Prof. Dr. Md. Abdul
Densities and viscosities of binary mixtures of Ethanol + Nitrobenzene (NB), n-Propanol + Nitrobenzene (NB), /so-Propanol + Nitrobenzene(NB), n-Butanol + Nitrobenzene (NB), iso- Butanol + Nitrobenzene (NB), n-Amyl alcohol + Nitrobenzene (NB), iso-Amyl alcohol + Nitrobenzene (NB) and Propylene glycol + Nitrobenzene (NB) have been studied over the entire range of composition (0 < x2 < I) at 298.15- 323.15K with an interval of 5K. The density of alcohols in pure state was found to be in the order of Propylene glycol> n-Amyl alcohol > n-Butanol > n-Propanol > Ethanol and iso-Amyl alcohol> iso-Butanol > iso-Propanol The values of densities of Alkanols + NB at equi-mole fraction systems has been found to be in the order of Ethanol+NB> n-Propanol+NB > n-Butanol+NB > n-Amyl alcohol +NB> Propylene glycol NB and iso-Propanol+NB> iso-Butanol+NB> iso-Amyl alcohol+NB The value of density of Alkanols in NB decreases with the increasing of composition of the Alkanols. The decrease of density with composition of Alkanols can be attributed to solute-solvent interaction. The densities of all Alkanols in pure state increase with the increasing of carbon number which may depend on the molecular weight of alcohols, structural formula and H-bonding of alcohols. The densities decrease regularly with the increasing of temperature. This is due to the thermal agitation and hence the weaker the dipole-dipole interaction or dissociation of H-bonding are occurred. At the 0.5 mole fraction, the density of Ethanol+NB is higher than other higher chain or branched chain Alkanols indicating that the nature of association of NB mostly disrupted in higher or branched chain Alkanols. The excess molar volume, VE for all the systems are positive over the entire range of composition, showing maxima at 0.5-0.8 mole fraction of Alkanols. The values of maxima of VE of Alkanols in NB solutions was found to be in the order of Propylene glycol+NB > n-Amyl alcohol+NB > n-Butanol+NB > n-Propanol+NB > Ethanol+NB and iso-Amyl alcohol+NB > iso-Butanol+N13 > iso-Propanol+NB and iso-Amyl alcohol+NB > n-Amyl alcohol+NB and iso-Butanol+NB > n-Butanol+NB and iso-Propanol+NB > n-Propanol+NB The increasing of VE with carbon chain length of Alkanols may be related to increase of the size of Alkanols. The values of VE for the studied Alkanols increase with the increase of temperature. The observed values of VE for the mixtures have been explained in terms of physical, chemical and geometrical contributions. The viscosity coefficients, ƞ of Alkanols + NB mixtures at six different temperatures have also been determined. The viscosities decrease initially slowly up to ~0.5-0.8 mole fraction of Ethanol, n-Propanol, iso-Propanol, n-Butanol, iso-Butanol, n-Amyl alcohol, iso-Amyl alcohol and Propylene glycol and later on, the viscosity increases sharply until the pure alcohol is reached. The viscosity of NB + Alkanols mixture at 0.5 mole fraction has been found to be in the order of Propylene glycol + NB> n-Amyl alcohol+ NB> n-Butanol >n-Propanol+ NB > Ethanol+ NB and iso-Amyl alcohol+ NB> iso-Butanol + NB > iso-Propanol+ NB and iso- Amy1 alcohol + NB > n- Amy1 alcohol + NB and iso-Butanol + NB> n-Butanol + NB and iso-Propanol + NB > n-Propanol + NB There is a marked decrease in the viscosity with increase of temperature for all the studied alcohols. This ascribed that the Alkanols + NB solutions are less stable at higher temperature. The increasing of viscosity with carbon number of Alkanols or branched chain Alkanols ascribed that the solution resistance increases with the increase of carbon chain length or branched chain. The linear dependence of lnƞ against 1/T shows for the all studied Alkanols + NB mixtures. The branched chain isomers are less stable than linear chain isomer at higher temperature. The excess viscosity, ƞ E values are found to be negative indicating that the Alkanols + NB system are non ideal. Excess viscosities are negative at all the temperatures over the entire range of composition for all the systems with minima occurring between 0.6-0.8 mole fractions. The negative excess viscosity, ƞ E of all the studied Alkanols + NB indicate that the dissociation of components through dispersive forces or steric hindrance. The position of minima virtually does not change remarkably with the variation of temperature. The values of the minima are in the order: Propylene glycol+NB> n-Amyl alcohol+NB > n-Butanol+NB > n-Propanol+NB > thanol+NB and iso-Amyl alcohol+NB> iso-Butanol+NB > iso-Propanol±NB and iso-Amyl alcohol+NB > n - Arnyl alcohol+NB and iso-Butanol±NB > n-Butanol+NB and iso-Propanol+NB > n-Propanol+NB The hydrophobic effect increases with the increasing of carbon chain length of alcohols. This indicates that the ƞ E decreases with the decrease of carbon number. The positive VE, negative ƞ E and negative interaction parameter (ɛ) for the studied Alkanols + NB systems indicate that dispersion force is dominant. Some disruptive force causing volume expansion may be present and it is more than compensated by volume contraction. The thermodynamic parameters such as free energy (∆G*), enthalpy (∆G*), and entropy (∆S*) change of activation for the viscous flow for these systems were examined for the entire range of composition. The free energy (∆G*) were found to be positive in magnitude indicating that the kinetic species involved in forming cavities or holes in the liquid medium is given by the work required in forming the hole against surface tension of the solution. The negative excess free energy, ∆G*E indicate that the strong dispersion force in Alkanols+ NB solution is dominant. The ∆H* values are positive for all the systems indicate that positive work has to be done to overcome the energy barrier for the flow process. The ∆S* values are found to be very small for all the studied systems indicating that the effects of ∆S* are negligible. The excess properties (VE, ƞ E, ∆G*E) data have been fitted by the least square method to the four parameters Redlich-Kister equation and the values of the parameter ai and standard deviation have been reported. The volumetric properties are fully consistent with viscometric and thermodynamic properties.
Studies on Volumetric and Viscometric Properties of Some Binary and Ternary Liquid Systems
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2011-11) Haque, Md. Fazlul; Motin, Dr. Md. Abdul
Densities and viscosities of binary mixtures of Methanol +DMF, Ethanol +DMF, n-Propanol +DMF, iso-Propanol +DMF, n-Butanol +DMF, iso-Butanol +DMF, tert-Butanol +DMF, nAmyl alcohol +DMF, iso-Amyl alcohol +DMF and ternary mixtures of n-Propanol +0.02M SDS in DMF, n-Butanol +0.02M SDS in DMF and n-Amyl alcohol +0.02M SDS in DMF have been studied over the entire range of composition (0 n-Amyl alcohol> iso-Amyl alcohol>iso-Butanol>n-Butanol> iso-Propanol> n- Propanol> Ethanol> Methanol There is a marked decrease in the viscosity with increase of temperature for all the isomeric studied alcohols. At 298.15K, viscosity is found to be in the order: tert-Butanol> iso-Butano!>n-Butanol iso-Propanol> n-Propanol, which however changes to n-Butanol >iso-Butanol> tert-Butanol n-Propanol> iso-Propano! at 323.15K. This ascribed that the branched chain isomers are less stable than linear chain isomers at higher temperature and vice versa. The η E values are found to be positive or negative, indicating that the DMF solutions of alcohols are non ideal. Excess viscosities are negative at all the temperatures over the entire range of composition for all the systems except Methanol with minima occurring between 0.6-0.9 mole fraction of n-Propanol, iso-Propanol, n-Butanol, iso-Butanol, tert-Butanol, n-Amyl alcohol and iso-Amyl alcohol. Excess viscosity of Methanol is positive at all the temperatures over the entire range of composition and show maxima in the DMF rich region at 0.2-0.4 mole fraction of Methanol. Excess viscosity of Ethanol is negative and show minima at 0.4-0.5 mole fraction of Ethanol. The position of maxima and minima virtually does not change remarkably with the variation of temperature. The heights of the minima are in the order: tert-Butanol> n-Amyl alcohol> iso-Amyl alcohol—iso-Butanol>n-Butanol> iso-Propanol> n- Propanol> Ethanol. The negative VE, positive and positive interaction parameter e for the DMF Methanol system may be ascribed that the interaction is strong, namely formation of Fl-bonding between DMF and Methanol. The negative yE, negative ηE and negative E for the DMF + rest of the studied alcohols systems indicate that dispersion force is dominant. For the later case,P'E is negative due to the segmental inclusion of DMF in the interstices of polymolecular alkanol aggregates. Some disruptive force causing volume expansion may be present, but it is more than compensated for by volume contraction through the segmental inclusion of DMF. The thermodynamic parameters such as, free energy (∆GH), enthalpy (∆H'H) and entropy (∆SH) change of activation for the viscous flow for these systems were determined for the entire range of composition by using Eyring's equation. The free energy (∆GH) were found to be positive in magnitude indicating that the kinetic species involved in forming cavities or holes in the liquid medium is given by the work required in forming the hole against surface tension of the solution. The excess properties (yE, ηE∆GHE) data have been fitted by the least square method to the four parameter Redlich-Kister equation and the values of the parameter a1 have been reported. Although the value of density and viscosity of the studied systems of 0.02M SDS in DMF solutions are slightly higher than the pure DMF solutions, but no appreciable change in the volumetric and viscometric properties were observed by the addition of the surfactants.
Studies on Volumetric and Viscometric Properties of Some iso-meric Alcohols in Surfactant Containing Ethanol Systems
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2015-12) Rahman, Md. Atiar; Motin, Prof.Dr. Md. Abdul
The critical micelle concentration (CMC) of Sodium Dodecyl Sulfate (SDS) in Ethanol was determined from the conductance, density and viscosity measurement. The estimated value of CMC was found to be 0.015 mol.L* The micellar concentration of SDS in Ethanol was used for the volumetric and viscornetric measurements of n-Propanol, iso-Propanol, n-Butanol, isoButanol, n-Pentanol and iso-Pentanol at different temperatures. Densities and viscosities of ternary mixtures of n-Propanol in 0.015M SDS+Ethanol, isoPropanol in 0.015M SDS+Ethanol, n-Butanol in 0.015M SDS+Ethanol, iso-Butanol in 0.015M SDS+Ethanol, n-Pentanol in 0.015M SDS+Ethanol and iso-Pentanol in 0.015M SDS+Ethanol have been studied over the entire range of composition (0 n-Propanol and iso-Pentanol> iso-Butanol > iso-Propanol. The value of density of alcohols in 0.015M SDS+Ethanol decreases with the increasing of composition of the alcohols. The decrease of density with composition of alcohols can be - attributed to dissociation of components. The densities of all alcohols increase with the increase of carbon number which may be depend on the molecular weight of alcohols, structural formula and H-bonding of alcohols. The densities decrease regularly with the increasing of temperature. This is due to the thermal agitation and hence the weaker the dipole-dipole interaction or dissociation of H-bonding are occurred. The excess molar volumes,VE were calculated from the densities of the mixtures at different temperatures. The values of VE for all the systems are positive over the entire range of composition, showing maxima 0.5 mole fraction of n-Propanol and - 0.5-0.6 mole fraction of iso-Propanol, 0.5-0.6 mole fraction of n-Butanol, --0.6 mole fraction of iso-Butanol, - 0.7-0.8 mole fraction of n-Pentanol and —0.8 mole fraction of iso-Pentanol. The excess molar volume, VE of alcohols in 0.015M SDS+Ethanol solutions was found to be order of n-Pentanol >n-B utanol >n-Propanol and iso-Pentanol >iso-Butanol >iso-Propanol and iso-Pentanol > n-Pentanol, iso-Butanol > n-Butanol and iso-Propanol > n-Propanol.The increasing of V with carbon chain length of alcohol may be related to increase of the size of alcohols. The values of [VE for the studied alcohols increase with the increase of temperature. The observed values of VE for the mixtures have been explained in terms of physical, chemical and geometrical contributions. The viscosity coefficients, r7 of all the above mixtures at all the six different temperatures have also been determined. The viscosities increase slowly up to entire mole fraction of nPropanol,iso-Propanol. For n-Butanol and iso-Butanol, the viscosities increase initially slowly up to -0.6 mole fraction and later on, the viscosity increases sharply until the pure alcohol is reached.. For n-Pentanol and iso-Pentanol, the viscosities increase initially slowly up to -0.8 mole fraction and later on, the viscosity increases very sharply until the pure alcohol is reached. In pure state the viscosity of alcohols has been found to be in the order of, iso-Pentanol >n-Pentanol> iso-Butanol > n-Butanol> iso-Propanol n-Propanol The increasing of viscosity with carbon number of alcohols ascribed that the solution > resistance increases with the increase of carbon chain length. There is a marked decrease in the viscosity with increase of temperature for all the studied alcohols. This ascribed that the alcohol solutions are less stable at higher temperature. The linear dependence of In)7 againstl/T shows for the all studied alcohols. The branched chain isomers are less stable than linear chain isomer at higher temperature.The excess viscosity, 77E values are found to be negative, indicating that the 0.015M SDS + Ethanol solution of alcohols are non ideal. Excess viscosities are negative at all thetemperatures over the entire range of composition for all the systems with minima occurring between 0.6-0.8 mole fraction of n-Propanol, iso-Propanol, n-Butanol, iso-Butanol, n- Pentanol and iso-Pentanol. The negative excess viscosity, rf of 0.015M SDS+Ethanol + All the studied alcohols indicate that the dissociation of components through dispersive forces or steric hindrance. The position of minima virtually does not change remarkably with the variation of temperature. The values of the minima are in the order: n-Pentanol>n-Butanol> n-Propanol and iso-Pentanol> iso-Butanol > iso-Propanol The hydrophobic effect increases with the increasing of carbon chain length of alcohols. This indicates that the ηE decreases with the decrease of carbon number. The positive VE, negative ηF and negative & for the 0.015M SDS+Ethanol + studied alcohols systems indicate that dispersion force is dominant. The thermodynamic parameters such as free energy (∆G), enthalpy (∆H) and entropy (∆S) change of activation for the viscous flow for these systems were examined for the entire range of composition. The free energy (∆G) were found to be positive in magnitude indicating that the kinetic species involved in forming cavities or holes in the liquid medium is given by the work required in forming the hole against surface tension of the solution. The negative excess free energy, ∆G indicate that the strong dispersion force in alcohols+ 0.01 5M SDS+Ethanol solution is dominant. The excess properties (VEηE ∆G*E) data have been fitted by the least square method to the four parameter Redlich-Kister equation and the values of the parameter a j and standard deviation have been reported. The volumetric properties are fully consistent with viscometric and thermodynamic properties.
Study of the Effects of Acetonitrile on the Alcohol Solutions by Volumetric and Viscometric Measurements
(2013-02) Monoranjan, Mondal; Motin, Dr. Md. Abdul
Densities and viscosities of binary mixtures of n-Propanol + Acetonitrile, iso-Propanol + Acetonitrile, n-Butanol + Acetonitrile, iso-Butanol + Acetonitrile n-Pentanol + Acetonitrile, iso-Pentanol + Acetonitrile and Propylene glycol + Acetonitrile have been studied over the entire range of composition (0 < x2 < 1) at 298.15- 323.15K with an interval of 5K. The studied alcohols or glycols are found to be dissolved completely in acetonitrile solutions at any composition. The density of alcohols or glycols in equi molefraction of acetonitrile solution was found to be order of Propylene glycols> iso-Pentanol> n -Pentanol > n-Butanol> iso-Butanol > n -Propanol > iso-Propanol. The value of density of alcohols in acetonitrile increases with the increasing of composition of the alcohols. The increase of density with composition of alcohols can be attributed to solute-solvent interaction. The densities of all alcohols increase with the increase of carbon number which may be depend on the molecular weight of alcohols, structural formula and H-bonding of lcohols. The density of Propylene glycol is higher than the studied alcohols owing to the higher degree of —OH and increasing unsaturation. The densities decrease regularly with the increasing of temperature. This is due to the thermal agitation and hence the weaker the dipole-dipole interaction or dissociation of H-bonding are occurred. The excess molar volumes, VE were calculated from the densities of the mixtures at different temperatures. The values of VE for all the systems are positive over the entire range of composition, showing maxima ~ 0.1-0.2 mole fraction of n-Propanol and ~ 0.4 mole fraction of iso-Propanol, ~ 0.4 mole fraction of n-Butanol ~ 0.4 mole fraction of iso-Butanol, ~ 0.3- ~ 0.4 mole fraction of n-Pentanol, ~ 0.5 mole fraction of iso-Pentanol and ~ 0.5 mole fraction of Propylene glycol . The excess molar volume, VE of alcohols in acetonitrile solutions was found to be order of Propylene glycol >n-Pentanol >n-Butanol >n-Propanol and iso-Pentanol > n-Pentanol and iso-Butanol > n-Butanol and iso-Propanol > n-Propanol. The increasing of VE with carbon chain length of alcohol may be related to increase of the size of alcohols. The values of VE for the studied alcohols increase with the increase of temperature. The observed values of VE for the mixtures have been explained in terms of physical, chemical and geometrical contributions. The viscosity coefficients, n of all the above mixtures at all the six different temperatures have also been determined. The viscosities increase initially slowly up to ~ 0.6 mole fraction of n -Propanol, iso-Propanol, n-Butanol, iso-Butanol, n-Pentanol, iso-Pentanol and Propylene glycol and later on, the viscosity increases sharply until the pure alcohol is reached specially at lower temperature. In pure state the viscosity of alcohols has been found to be in the order of, propylene glycol > iso-Pentanol n-Pentanol > iso-Butanol > n-Butanol > iso-Propanol > n- Propanol There is, a marked decrease in the viscosity with increase of temperature for all the studied alcohols. This ascribed that the alcohol solutions are less stable at higher temperature. The increasing of viscosity with carbon number of alcohols ascribed that the solution resistance increases with the increase of carbon chain length. The linear dependence of In77 against 1/T shows for the all studied alcohols. The branched chain isomers are less stable than linear chain isomer at higher temperature. The excess viscosity, ƞE values are found to be negative, indicating that the acetonitrile solutions of alcohols are non ideal. Excess viscosities are negative at all the temperatures over the entire range of composition for all the systems with minima occurring between 0.6-0.9 mole fraction of n-Propanol, iso-Propanol, n-Butanol, iso-Butanol, n-Pentanol, iso-Pentanol and Propylene glycol. The negative excess viscosity, ƞE of acetonitrile + all the studied alcohols indicate that the dissociation of components through dispersive forces or steric hindrance. The position of minima virtually does not change remarkably with the variation of temperature. The values of the minima are in the order: Propylene glycol ~ iso-Pentanol > n-Pentanol> iso-B utanol>n-Butanol > iso-Propanol> n-Propanol The hydrophobic effect increases with the increasing of carbon chain length of alcohols. This indicates that the ƞE decreases with the decrease of carbon number. The positive VE, negative ƞE, and negative ε for the acetonitrile + studied alcohols systems indicate that dispersion force is dominant. Some disruptive force causing volume expansion may be present and it is more than compensated by volume contraction through the segmental inclusion of acetonitrile. The thermodynamic parameters such as free energy (ΔG*E), enthalpy (ΔH*) and entropy (ΔS*) change of activation for the viscous flow for these systems were examined for the entire range of composition. The free energy (ΔG*) were found to be positive in magnitude indicating that the kinetic species involved in forming cavities or holes in the liquid medium is given by the work required in forming the hole against surface tension of the solution. The negative excess free energy, ΔG*E indicate that the strong dispersion force in alcohols-acetonitrile solution is dominant. The excess properties (VE, ƞE, ΔG*E) data have been fitted by the least square method to the four parameter Redlich-Kister equation and the values of the parameter ai and standard deviation have been reported. The volumetric properties are fully consistent with viscometric and thermodynamic properties.
Study of the Effects of Electrolytes on the Carbohydrate Solutions with Volumetric and Viscometric Measurements
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2012-11) Alam, Sheikh Ahidul; Motin, Dr. Md. Abdul
In this study, a simple volumetric and viscometric method was used for the analysis of effect of body containing electrolytes such as NaCl and KC1 on the carbohydrates (glucose, sucrose and maltose) solution. The densities and viscosities of NaCl and KCI at different concentration in aqueous and aqueous glucose, aqueous sucrose and aqueous maltose (1% (w/v), 5% (w/v) and 10% (w/v)) solutions have been determined at 298.15, 303.15, 308.15, 313.15, 318.15 and 323.15 K respectively. The studied electrolytes are found to be dissolved readily in aqueous and aqueous carbohydrate (upto 10% (w/v)) solutions. The density of glucose, sucrose and maltose in aqueous solution were found to be order of Maltose > Sucrose > Glucose. The value of density of NaCl and KCI increases with the increasing of molarity of the electrolytes. Densities of electrolytes in aqueous carbohydrate solutions are concentration of electrolyte can be attributed to solute-solvent interaction. The apparent molar volumes, ɸv were obtained from these densities data. The limiting apparent molar volumes, ɸºv and experimental slope, Sv derived from Masson equation have been interpreted in terms of solute- solvent interactions. The sign of --- i.e. second [(∂^2 〖 Ø v 〗^ )/(∂〖 T 〗^2 )]P derivative of limiting apparent molar volume of solutions with respect to temperature at constant pressure which corresponds to structure making or breaking properties of solutes were determined. NaCl in water, 1% (w/v) glucose and 1% (w/v) maltose solution, the value of [(∂^2 〖 Ø v 〗^ )/(∂〖 T 〗^2 )]P were found to be slightly positive suggesting structure making property. In case of sucrose it shows negative value of [(∂^2 〖 Ø v 〗^ )/(∂〖 T 〗^2 )]P for all the electrolytes containing solvent systems indicating structure breaking property. KCI in water and carbohydrate solution, the values of [(∂^2 〖 Ø v 〗^ )/(∂〖 T 〗^2 )]P were found to be negative suggesting structure breaking tendency. The viscosity vs molarity plots for all the electrolytes systems are linear in all the solvent systems with some exceptions. The viscosity, ƞ for all the studied electrolytes are greater in aqueous carbohydrate solvent system than those in water system. The viscosities coefficients A and B were determined from viscosities data on the basis of Jones Dole equation. The coefficient B gives information regarding solute - solvent interaction and shape and size effect on the solvent structure. The coefficient A represents the ion-ion interaction. The B-coefficient for NaCl in aqueous and aqueous glucose, aqueous sucrose and aqueous maltose solutions (1% (w/v)) at all the temperatures are positive. The positive value of the B-coefficient corresponds to the structure making behavior of solutes. The B-coefficient for KC1 in water and carbohydrate solutions (1%, 5% and 10% (w/v)) are negative. The negative value of B-coefficient corresponds to the structure breaking behavior of KCl. The sign of dB/dT corresponds to structure making or breaking properties of solutes, were determined. For NaCl in aqueous and aqueous carbohydrates (1% (w/v)) solutions, the values of dB/dT are negative which corresponds to structure making behavior. For aqueous and aqueous carbohydrate solution (1%, 5% and 10% (w/v)) of KC1, the values of are positive which corresponds structure breaking behavior.The free energy of activation, ΔG≠ for viscous flow was calculated using Nightinagle and Benck equation at the experimental conditions. Activation enthalpy, ΔH≠ and activation entropy, ΔS≠ were calculated using the Eyring equation and other thermodynamic relations. The effects of electrolytes on the structure of water and aqueous carbohydrate solutions were interpreted in terms of apparent molar volumes, viscosities and viscosity coefficients (A and B) values and thermodynamic parameters (ΔG≠, ΔH≠, ΔS≠).
Study on Physico-Chemical Properties of Rain Water, Ground Water and Pond Water in KUET Premises
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh, 2014-05) Rahman, Md. Aminur; Badal, Dr. Md. Mizanur Rahman
Six samples of pond water, four samples of rain water and four samples of ground water were collected from the KUET premises. The sampling of pond water has been made during the period Nobember, 2013 to April 2014, while the rain water samples were collected during the late rainfall in the month of September. The rain samples were mounted 1.5 meters above the ground to avoid rain splash as recommended Pond water samples were collected by grab-sampling method. All sample's were filtered and preserved at 200 C. Some water parameters such as Alkalinity, Hardness, TDS, Arsenic, pH, Turbidity, Conductivity & Salinity were measured. Four tube well water samples were collected from different location of KUET residential area. The pH of tube well water ranged from a minimum of 7.79 to a maximum of 8.2 of TW3 (Tube well water, collected from building no 12) and 1W1 (Tube well water, School gate KUET) respectively. Similarly the variation of pH of pond water ranged from a minimum of 8.40 to a maximum of 8.87 of PWL1 (Pond water lower Position, Rokaya hail) and in rain water the maximum value was 6.77 of RWJ1 (Rain water from jessore urban) and the minimum value was 6.34 of RWC (Rain water collected from Chittagong) respectively. The values of conductivity for all tube well water were found to be greater than those of pond water and rain water. In present observations the conductivity for tube well water ranges from 1021 to 1598 ts/cm, for pond water ranges 324 to 732 p.s/cm and for rain water ranges from 13 to 80 J.ls/cm. It indicates that the tube well water contain larger quantity of dissolved mineral salts. In case of pond water, the conductivity is also significantly change during winter season and rainy season. The total dissolved solids (TDS) of tube-well water ranged from a minimum of 551 rng!L to a maximum of 887 mg/L of TW1 (Tube-well, School gate) and TW4 (Tube well water,collected from building no 19) respectively. Similarly the variation ctotal dissolved solids of pond water ranged from a minimum of 175 mg/L to a maximum of 399 mg/L of PWL 1 (Pond water, lower Position Rokaya hail) and PWL2 (Pond water, lower Position power plant side pond) and for rain water ranged from a minimum of 6 mg/L to a maximum of 40 mg/L of RWC (Rain Water, Collected from Chittagong) and R\VK (Rain Water, Collected from Khulna) respectively. This high values of TDS (Total dissolved solids) specially in Tube well water are mainly due to carbonates, bicarbonates, chlorides, phosphates and nitrates of calcium, magnesium, sodium, potassium and manganese. The variation in total alkalinity of tube-well water ranged from a minimum of 496.66 mg/L to a maximum of 508.33mg!L of TW2 (Tube well water, collected from building no 5) and TW3 (Tube well water, collected from building no 12) respectively . Similar variation in total alkalinity of pond water ranged from a minimum of 83.33 mg/L to a maximum of 131.66 mg/L of PWL1 (Pond water, lower Position Rokaya hail) and PWU3 (Pond water, collected from upper Position Khan Jahari Ali Hall) respectivcly. Tube-well water samples have found the iron content and the results varied from 16.78 27.97 ppm. No tube-well was found having the iron content within the maximum permissible limit of 1.0 ppm. Lead and cadmium concentration in the rain water was found below the detectable limit. Arsenic was investigated to all tube well water and found below 0.02 ppm that is within acceptable limit.