Study of Chromium (vi) Adsorption Using Pterospermum- Acerifolium Fruit Capsule Activated Carbon (fcac) and Commercial Activated Charcoal (cac) as a Selective Adsorbents

In the present study, fruit capsule activated carbon (FCAC) of P-acerifolium and commercial grade activated charcoal (CAC) were used for the study of adsorption of chromium (Vl) from aqueous solution. The maximum adsorption took place in the pH range of 3-6 with in contact time of 180 minutes. The adsorption kinetic of chromium (Vl) analyzed by pseudo first-order and pseudo second-order kinetics models. The kinetics of chromium (Vl) uptake was best described by pseudo-second order rate model (regression coefficients, R 2 >0.99) with equilibrium rate constant values of 2.70 and 1.42 g/mg.min. for FCAC and CAC adsorbents. Intraparticle diffusion studies showed that the intraparticle transport is not only the rate-limiting step for the mechanism of chromium (Vl) adsorption. The experimental results presented indicated that the adsorption data fitted better with the Langmuir isotherm equation with regression coefficient R 2 > 0.99 for both the adsorbents. The maximum monolayer adsorption capacity of FCAC and CAC found to be 76.92 and 71.42 mg/g at initial pH 3.0. Thermodynamic parameters showed that adsorption process was spontaneous and endothermic. A comparative study of FCAC with commercial activated charcoal (CAC) showed that the adsorption capacity of indigenously prepared FCAC adsorbent was much better.