A Study on Bentonite supported Nano Iron for Removal of Cr (Ⅵ) in Groundwater

Abstract

Abstract:

With the development of living standard and urbanization, groundwater pollution is becoming serious. It is hazardous to human health, ecotope and social security with the heavy metal and organic field pollutants. The issues of Cr(Ⅵ) contaminated groundwater are paid more attention on recently. As Cr(Ⅵ) has high toxicity and mobility in water compared to Cr(Ⅲ), it is very important to deposit chromium by reduction of Cr(Ⅵ) into Cr(Ⅲ) using nano iron; therefore, the contaminants in source region are stabilized and indiffused from all around. While the agglomeration and oxidation of nano iron is often unavoidable due to the very small particles, it is essential to study the disperse and stability of nano iron. In this paper, bentonite was used as a porous based support material for synthesized nano iron. The results showed as follows. (1) Bentonite supported nano iron particles are well sphere scattering on the bentonite. (2) The removal efficiency of B-NZVI is better than NZVI comparing the same iron content (1 g/L) B-NZVI, NZVI and 1 g/L bentonite. Reduction kinetics of Cr(VI) by B-NZVI were described by a pseudo first order reaction. Kinetics studies of Cr(Ⅵ) reduction using B-NZVI suggested that the reactivity of NZVI particles supported on bentonite were decreased significantly with the decrease of initial iron content. (3) Column experiments showed that B-NZVI was no migratory in the column packed silicon dioxide and it indicated B-NZVI is suitably applied in point source pollution. Breakthrough curve of Cr(Ⅵ) in the column was obtained for reference to application.

Key words: bentonite；nanoiron；Cr(VI)；batch experiment, column experiment

LI Chen-Hua, CHEN Jia-Wei. A Study on Bentonite supported Nano Iron for Removal of Cr (Ⅵ) in Groundwater[J]. Geoscience, 2012, 26(5): 932-938.

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