Adsorption of Hexavalent Chromium from Aqueous Solutions by Low Cost Biosorbents

摘要

In this research, adsorption of chromium (VI) ions on biological waste products has been studied using column adsorption techniques. The main objectives of this study are to 1) investigate the comparative ability of low cost biosorbents in the form of hybrid system of Albizzia lebbeck and Groundnut shell pods and of pure groundnut column by designing packed bed reactor for the removal of Cr (VI) ions from aqueous solution & electroplating industrial effluent 2) study the influence of contact time, pH, adsorbent dose and initial chromium concentration on adsorption process performance and 3) determine appropriate adsorption isotherm and kinetics parameters of chromium (VI) adsorption. The results of this study showed that in a hybrid column, 96.7% of Cr (VI) removal from industrial effluent took place by hybrid column. The pH and flow rate are optimized to be 2-3 and 0.3 ml/min respectively. Comparatively in a pure groundnut column, % Cr (VI) removal decreases to 89.9% under same conditions. The column can be regenerated by treating with 0.1M H_2SO_4 / 0.2M K_2SO_4. The % recovery achieved was 98.44%. The total binding capacity of hybrid and pure columns was observed to be 61mg and 41mg respectively. From this study it can be concluded that Hybrid column is much more efficient than Pure GNSP column for the removal of Cr (VI) at high concentrations.