ENHANCEMENT OF CHROMIUM REMOVAL FROM WATER BY BIO-ADSORPTION USING EDTA-TREATED RICE STRAW

Document Type : Original Article

Author

Soils, Water and Environ. Res. Inst., ARC, Giza, Egypt

Abstract

Using factorial experiments, rice straw of 1g or 2g weight was immersed into 100 ml of water solution of different concentrations of Cr  (25, 50 and 75 mg Crl), in a form of Cr-chloride ‘CrCl3. 6H2O’. The contact and shaking time intervals were 60, 90 and 120 minutes and the solution pH values were 5, 7 and 9. One experiment was conducted for each of the 1g and 2g non- ethylenediamine tetra acetic acid (EDTA)-treated straw and one experiment for each of the 1g and 2g EDTA-treated straw. In terms of the amount of Cr removed from solutions, it increased as the initial concentration increased. In terms (%) removal from the initial concentration, the removed portions decreased as the initial concentration increased. Treating the straw with EDTA and increasing the time of contact enhanced the removal. High removals occurred with the neutral or alkaline pH. Lowest (%)  removal was  24% for the treatment of 1g non-EDTA straw of  the 75 mg Crl solution of pH 5 and the shortest  contact time of 60 min. Highest (%) removal  of 100% was obtained by the treatment of 2g EDTA straw in the 25 mg Crl of either pH 7 or 9 and longest contact time of 120 min.

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