Continuous flow chromium (VI) adsorption onto peach stone- and acrylonitrile-divinylbenzene copolymer-based activated carbons

Abstract

Peach stone-based activated carbon (PS-AC) and acrylonitrile divinyl benzene copolymer-based activated carbon (ANDVB-AC) were evaluated in fixed-bed continuous flow Cr(VI) adsorption studies. The results were compared with those for the commercial activated carbon (CPG-LF). Continuous flow adsorption studies were carried out in a fixed-bed column with various concentrations of a Cr(VI) solution of pH 2. The effect of flow rate on the breakthrough capacity was investigated via breakthrough curves. Although total Cr(VI) adsorption capacities were obtained as 122, 58, and 103 mg/g for PS-AC, ANDVB-AC and CPG-LF, respectively, the breakthrough capacities were determined to be 25.0, 35.2, and 30.0 mg/g. When polymer-based AC was used, 61% of the capacity was effectively utilized while with peach stone-based AC, only 21% of the capacity was effectively utilized at a flow rate of 5 mL/min. This difference was attributed to the shorter contact time of the solution in the column and the slower adsorption kinetics of PS-AC. At a lower flow rate (0.96 mL/min) peach stone-AC can be utilized with higher (47%) efficiency. Both peach stone- and polymer- based activated carbons can be effectively utilized in a fixed column under continuous flow with high Cr(VI) adsorption capacities.