Bioremediation of hexavalent chromium from electroplating wastewater at Luwero Industries Limited using rice husks

Abstract

In this research, the specificity of wastewaters formed in the surface treatment at LIL and the method of treatment by bioremediation is considered. The purpose of this research is to suggest a cheap and effective chemical method of adsorbing chromium from the waste water. This adsorption process involved the following steps; carbonizing the rice husks, decolorizing, mixing with ethylene diamine under specified conditions, drying, performing batch experiments using sodium dichromate solution and analyzing the residual chromium using a spectrometer. The modified bio-sorbent rice husk powder has been successfully utilized for the removal of Cr (VI) from wastewater. The maximum removal of Cr (VI) was found to be 88.3% at pH 4, initial Cr (VI) concentration of 200 mgl−1, and temperature 20 ◦C. The effect of different parameters such as contact time, adsorbate concentration, pH of the medium, and temperature was investigated. Mass transfer of Cr (VI) from the bulk to the solid phase (rice husk powder) was studied at different temperatures. Desorption studies was also carried out and found that complete desorption of Cr (VI) took place at pH of 9.5.