Comparative Study of Chromium (VI) Removal by Activated Neem leave Powder and Neem Saw Dust : Isotherms & Kinetics

Department of Chemical Engg, Haldia institute of technology. Haldia -721657, India Department of Chemical Engg, Meghnath Saha Institute of Technology, Haldia Associate Manager , Linde India Limited., Kolkata Email Corresponding Author : radha.das6@gmail.com, Effluents from various industries like electroplating, leather tanning, cement, petrochemicals, dye etc, contains significant amount of toxic hexavalent chromium, Cr(VI) with concentration of 10th to 100th ppm level. To avoid the health hazard from long term exposure of Cr(VI) , there is high high demand of feasible cost effective technologies which would eventually save aquatic & human lives from the carcinogenic effect of Cr+6. In this work activated Neem leaf powder (NLP) and Neem saw dust (NSD) were selected as cost effective adsorbent for elimination of chromium (VI) compound from synthetic waste water using adsorption process at various pH, concentration , time and temperature. It was observed that the reduction of Cr+6 increases with the increase of time of contact and adsorbent amount but decreases with higher solute concentration. Determination of free Cr+6 ions concentration in the effluent has been determined Spectro-Photometrically at 542 nm wavelength. The results show that 98 - 99.88 % reduction of Cr+6 may be achieved successfully depending on pH and nature of adsorbents, temperature and concentration of solution. The rate constants of these sorption processes were observed using pseudo first order and pseudo second order reaction kinetic models. Freundlich Isotherm and rearranged Langmuir model were used to find out the applicability of these isotherms for both adsorption processes. Results also show that the performance efficiency of activated NLP was slightly higher compared to the NSD at the same sorption conditions. The maximum adsorption of Cr(VI) was obtained as 55.86 and 40.0 mg/gm using NLP and NSD respectively