Removal Of Hexavalent Chromium From Industrial Waste Water Using Activated Carbon Derived From Khat Stem

Abstract

Chromium released from industry lead to massive environmental pollution and have tendency to accumulate in certain parts of the human body and become harmful to life. In this study stems of khat used for preparation of activated carbon collected from East Shoa Zone AdamaKhatterawere investigated as adsorbent for removal of Cr (VI) from industrial effluents. The adsorbent was characterized by Point of zero charge pH, FT-IR, XRD and SEM analysis. Point of zero charge pH and FT-IR test, showed the presence of acidic functional groups on surface. The study was employed with 150µm - 250µm particle size and efficiency of adsorbentwasinvestigated at different parameters such as pH, initial concentration, adsorbent dose and contact time. Optimum parameters pH 2, dose 1g, concentration 50(mg/L) and contact time 180min were obtained. Result revealed that chromium (VI) removal was pH sensitive and 96 % and above removal capacity was recorded at Optimum parameters. Using optimum parameters; isotherm and kinetics of the adsorption process was analysed using different model. The result showed that isotherm model of the process fitted well the Freundlich adsorption isotherm model and kinetics of adsorption is well defined by the pseudo-second-order. The maximum adsorption was found to be 4.8 (mg/g). The efficiency of activated carbon derived from khat stem to remove Chromium (VI) from real sample at optimized condition was 91.004 % and it was identified that ACDKS can be used to remove Chromium (VI) from tannery industry.