M.Phil.

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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.
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 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 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 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
Synthesis and Characterization of Some Biologically Active Copper Complexes for Microbial Applications
(Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh., 2015-06) Khan, Mohammed All Azom; Aziz, Prof. Dr. Md. Abdul
In this study, in order to verify our hypothesis amino acid base copper complexes have been prepared for biological application. Reaction of tcydan and Cu(C104)2 6H20 with nucleobases (adenine, hypoxanthine and theophylline) gave three tcydan—metal—amino-acid base complexes, Cu(tcydan)(ade)] .C104.2H20 (1), [{ Cu(tcydan) }2(hypoxanth).(CIO4)3 (2) and H20/CH3 [Cu(tcydan)(theophy)]3.(C104)3.2H20 (3). The complexes were prepared in H CN media at room temperature under pH 8-9. The crystal structures were determined by X-ray diffraction. In the structure of complex 1, the square-pyramidal Cu 2+ ion binds to an adenine ligand through the deprotonated N(9) and to four nitrogens of a tcydan ligand, and an interligand hydrogen bond is formed between the secondary amino nitrogen of tcydan and the ring nitrogen N(3) of the base. In complex 2, two square-pyramidal Cu2 ions bind to a xanthine ligand, one through N(7) with the formation of a hydrogen bond between the exocyclic oxygen 0(6) of the base and the secondary amino nitrogen of a tcydan ligand, and the other through the deprotonated N(9) with the formation of a hydrogen bond between N(3) of the base and the amino nitrogen of tcydan. In the structure of complex 3, the square-pyramidal Cu 2+ ion binds to a theophyllinato ligand through N(7) and four nitrogens of a tcydan ligand with the formation of a hydrogen bond between 0(6) of the base and amino group of tcydan, as observed in 2 and 3. In summary, the adenine complex 1 involves the metal-N(9) bonding with the formation of an N(3) hydrogen bond. On the other hand, the absence of the possible metal bonding to N(7) or N(I) of adenine might be due to a steric repulsion, intramolecular interligand N(tcydan)-H ...between amino groups of tcydan and the N(6) amino group when the metal ion binds to N(7)or N(l) of the base. Synthesized Cu-complexes are quite capable of removing Fecal coliform (FC) from water.
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.
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.
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.

M.Phil.

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