Humic acid coated cellulose derived from rice husk: A novel biosorbent for the removal of Ni and Cr

Biosorption using cellulosic wastes has been considered as a clean technology for the uptake of heavy metals. In this study, a novel biosorbent was synthesized by extracting the cellulose from the waste rice husk using soda bleaching technique followed by its coating using humic acid. The biosorbent was found to be very effective for the removal of nickel and chromium from the aquatic medium. Various physicochemical conditions for uptake like pH (5-6), contact time (8 h) were optimized using batch method.The sorption capacity enhanced significantly by providing humic acid coating. Experiment data were fitted in sorption isotherm and kinetic modelstodescribe the sorption process.Sorption capacity of developed biosorbent was 12.41 mg g(-1) and 19.39 mg g(-1)for nickel and chromium respectively and the sorption followed the Langmuir isotherm for both the elements.