Utilization of Poly(acrylic acid)- Bentonite Composite for the Sorption of Chromium from Aqueous Solutions

The utilization of polymer-clay composites as adsorbents in the remediation of polluted water has been the subject of many recent research studies. In the present work, poly(acrylic acid) –bentonite (PAA-Bentonite), was synthesized and its chromium ion adsorption performance was investigated. The adsorption behavior of the composite towards chromium from aqueous solution was studied under varying conditions such as initial concentration of chromium (5–500 mg/L) and contact time (30–1440 min). Experimental equilibrium data were fitted to Langmuir and Freundlich isotherm models by non-linear regression method, however, the adsorption equilibrium data were well interpreted by the Langmuir model. The maximum capacity of PAA-Bentonite toward chromium was 29.55 mg/g at 25 °C, which was much higher than that of the Bentonite (1.3 mg/g). The maximum chromium removal efficiency of 85 % was achieved by the composite at 25°C with 30 min contact time for an initial metal concentration of 50 mg/L. The adsorption kinetics followed both pseudo first-order and pseudo second-order models.The results showed the high potential of PAA-Bentonite composite for the removal of chromium ions from aqueous solution.