Inexpensive Adsorption Technique to Remove Cr(VI) from Aqueous Solutions

The removal of Cr(VI) from aqueous solutions by using an inexpensive adsorbent, viz. China clay has been investigated. Maximum uptake (68%) was observed at a solution concentration of 0.5×10 −4 M, pH 2.5 and 30°C. The kinetics of the process have been explained using the Lagergren equation; the average rate constant of adsorption was found to be 0.148 min −1 . Langmuir's isotherm was found to be valid; the constants are calculated for different temperatures. The rate-limiting factor is the intraparticle diffusion. The coefficients of mass transfer and intraparticle diffusion are determined at different temperatures. In the present study low temperatures as well as low pH favour the uptake of Cr(VI) species.