Synergistic Interactions between Activated Carbon Fabrics and Toxic Hexavalent Chromium

Abstract

The synergistic interactions between the activated carbon fabrics (ACFs) and the toxic Cr(VI) were investigated aiming to functionalize the ACFs and to remove the toxic Cr(VI). The effects of pH, treatment time, initial Cr(VI) concentration and ACFs dose on the Cr(VI) removal were studied. Different pH values had different effects on the Cr(VI) removal by ACFs, pH = 1.0 was found to be the optimum. For the pH = 1.0 solution, the Cr(VI) in the aqueous solution was reduced to Cr(III) and adsorbed onto the ACFs, and the C-O and C=O functional groups were found on the ACFs surface. The redox kinetic in the pH = 1.0 solution could be described by the pseudo-first-order model and the typical value of the pseudo-first-order rate constant was calculated to be 0.0872 min−1. Langmuir, Freundlich, and Temkin adsorption isotherm models were applied to describe isotherm behaviors. The Cr(VI) equilibrium data agreed well with the Langmiur isotherm model with a maximum adsorption capacity of 5.59 mg g−1. The ACFs could be easily regenerated by 1.0 mol L−1 sodium hydroxide and effectively recycled 7 times with the removal percentage decreased by 16.5%, which was caused by the irreversible formation of oxygen functional groups on the surface of ACFs.