Adsorption of Aqueous Cr(VI) on Polyaniline: Adsorption Isotherms and Adsorption Kinetics

In the study, polyaniline (PAN) was used as adsorbent to remove Cr(VI) from aqueous solutions. Adsorption kinetics and isotherms of Cr(VI) onto the PAN were determined by batch experiments. Results showed that the experimental data of adsorption isotherms can be fitted greatly by the Freundlich model, which indicated that the adsorption process is heterogeneous. Temperature had less effect on the adsorption of Cr(VI) on PAN, The adsorption capacity of PAN were 3.36mmol/g, 3.46mmol/g and 3.58mmol/g at the temperature of 15 degrees C, 25 degrees C, 35 degrees C. Adsorption kinetics of Cr(VI) over PAN obeyed pseudo-second-order model. The Cr(VI) adsorption on PAN was highly pH dependence and Cr(VI) adsorption amount on PAN decreased monotonously with increasing pH. The adsorption amount of Cr(VI) is 4.93mmol/g at 25 degrees C and pH 2.28.