Assessment of antimony as a priority pollutant and exploration of antimony removal from aquatic environment

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2017
Yücel, Özge
Antimony is a metalloid element that has adverse health and environment effects at high concentrations. In this study, the antimony mining site located in the Yeşilırmak River Basin is considered as a point source and removal of antimony from aquatic environment was explored. Results indicated that surface waters in the downstream of antimony reserve are susceptible to antimony pollution. Samples collected near vicinity of the antimony mining site have exceeded Environmental Quality Standards (EQS) of antimony more than 200 times. The most effective treatment methods for antimony in aqueous environment were explored and most effective processes were identified as adsorption, membrane processes and coagulation/flocculation. In this study, natural zeolites were utilized to remove antimony ions by adsorption. Clinoptilolite originated from Gördes, Manisa deposit was investigated in its natural form for its effectiveness in removing antimony from aqueous solutions. Throughout this work, equilibrium and kinetic studies were performed with zeolite that has approximately 40 m2/g surface area. The results of equilibrium studies revealed that zeolite adsorption capacity for Sb ions increases as pH of the sample decreases. Maximum capacities attained were 2.02 mg/g for 50 mg/L initial Sb concentration. At lower initial Sb concentrations, adsorption capacities observed for zeolite was found significantly lower. For the optimum conditions, the highest removal efficiency for antimony removal achieved as 85 % by zeolite adsorption. Due to low adsorption capacity of zeolite, membrane processes were also investigated. With nanofiltration (NF270 membrane), removal efficiency was higher than 80 %, and it was possible to reach 99 % removal with Reverse Osmosis (SW30 membrane). Moreover, as an alternative method, coagulation/flocculation processes were studied with two common conventional coagulants, ferric chloride and aluminum sulfate. It was seen that 99% removal was achieved via conventional coagulation and flocculation process with ferric chloride. On the other hand, only 44% removal was achieved with aluminum sulfate. 
Citation Formats
Ö. Yücel, “Assessment of antimony as a priority pollutant and exploration of antimony removal from aquatic environment,” M.S. - Master of Science, Middle East Technical University, 2017.