REMOVAL OF HEXAVALENT CHROMIUM USING ACTIVATED COCONUT SHELL AND ACTIVATED COCONUT COIR AS LOW COST ADSORBENT

Studies were conducted to assess the comparative efficiency of activated coconut shell and activated coconut coir in removing toxic hexavalent chromium from its synthetic solution and tannery industrial effluent in batch mode. The parameters studied include- pH, adsorbent dose, contact time & initial metal ion concentration and the applicability of adsorption isotherms. Activated coconut shell exhibited more adsorption potential as compared to Activated coconut coir and maximum removal exhibited by ACS was 88% and 83.0 % for 0.3 mm and 1.0 mm in case of synthetic solution & 76%(0.3mm) and 66%(1.0mm) in case of tannery effluent at optimized conditions (pH =2, dose=1.0g/100ml, contact time=60 minutes & initial metal ion concentration=10 ppm). In general ACS was observed to be better adsorbent than ACC while adsorbents of particle size 0.3 mm have greater efficiency than 1.0 mm. On application of adsorption kinetics, Adsorption of Cr (VI) by ACS and ACC followed the pseudo first order and pseudo second order model. The results showed that the activated coconut coir is an efficient adsorbent for hexavalent chromium removal.