Novel approach to control adsorbent aggregation： iron fixed bentonite-fly ash for Lead (Pb) and Cadmium (Cd) removal from aqueous media

摘要

In the present study,a novel approach was used to control zero valent iron aggregation and separation problems by fixing zero valent iron (ZVI) on bentonite-fly ash pellets.For this purpose,porous low cost bentonite-fly ash (BFA) pellets with size of 2.00 cm in length and 0.35 cm in diameter were prepared and fixed with ZVI to manufacture zero valent iron bentonite-fly ash (ZVI-BFA) pellets.Importantly,unlike powdered adsorbents,ZVI-BFA can easily be separated from final effluents when exhausted without any disintegratign.The performance of the developed novel adsorbent was investigated for the removal of Pb2+and Cd2+ from aqueous media.At 100 mg.L and 1 g adsorbent,a maximum of 89.5％ of Cd2+ and 95.6％ ofPb2+ was removed by ZVI-BFA as compared to 56％ and 95％ removal by BFA.At 200 mg.L-1,Cd2+ and Pb2+ removal by ZVI-BFA was 56％ and 99.8％ respectively as compared to only 28％ and 96％ by BFA.Further,the removal kinetics was best fitted for pseudo-second order model.The study provides the basis for improving the removal capacity of porous materials by iron fixation while taking separation ability into consideration.