Intensification of Cr(VI) adsorption using activated carbon adsorbent modified with ammonium persulfate.

Granular activated carbon has been modified by ammonium persulfate as a new adsorbent for Cr(VI) adsorption from aqueous solutions. The adsorbent was characterized by nitrogen adsorption-desorption isotherm data and infrared spectroscopy. The impact of different factors, such as the initial pH level of the solution, time, temperature, ionic strength, and initial concentration of the Cr(VI) ion, on the adsorption efficiencies of the adsorbent has been studied by batch experiments. Kinetic studies and the adsorption thermodynamics of Cr(VI) with ammonium persulfate-modified activated carbon adsorbent were carefully studied. The results showed that the Cr(VI) adsorption follows a pseudo-second-order kinetic model and the adsorption reaction is endothermic and spontaneous. The adsorption isotherm was scrutinized, and the fitting results showed that the Langmuir model could well represent the adsorption process. The maximum adsorption capacity of Cr(VI) onto persulfate-modified activated carbon was 108.69 mg g. The research results showed that using persulfate-modified activated carbon adsorbent can greatly remove Cr(VI) from aqueous solutions.