Synthesis of zirconia nanopowders from local zircon sand and study the influence of crystal structure on photocatalytic activity

Abstract

In the present study purification of natural zircon sand was performed by hydrometallurgical method and zirconia (ZrO2) nanopowders were synthesized from the purified zircon. Later influence of crystal structure on photocatalytic activity was investigated. The characterization and upgradation processes were employed on local ZrSiO4 sand collected from Cox’s Bazar Sea Beach via Beach Sand Minerals Exploitation Center (BSMEC). Traditional beneficiation methods like acid leaching and alkali leaching were performed. As received sample contained 73.8% ZrSiO4 which turned 86.3% purity after upgradation. Major impurity rutile (19.8%) was removed completely through these beneficiation processes. The particles found uniformly distributed and possessed negligible amount of moisture. Standard tetragonal phase of ZrSiO4 was found in the as received sample which didn’t show any phase transition at low temperature (up to 750oC). Through consecutive alkali-fusion, co-precipitation followed by calcination ZrO2 nanoparticle with different phases were formed from ZrSiO4nano powder. Depending on calcination temperature ZrO2 showed different crystal structure. Calcination at 800oC and 1000oC showed predomination of tetragonal ZrO2 whereas comparatively high temperatures (1100oC and 1300oC) showed mostly monoclinic structure. Zirconia samples with different crystal structures were used to decolorize Methylene Blue dye.Calcinedsample at 1100oC showed maximum decolorization (71.75%) efficiencydue to presence of combined monoclinic, cubic and tetragonal phases. The result concludes that nanoparticle of zirconia can be synthesized from local zircon sand and it can be used forphotodegradationof textile dye.