Effect of modification with nitric acid and hydrogen peroxide on chromium (VI) adsorption by activated carbon fiber

摘要

The activated carbon fiber (ACF) was treated by different concentration nitric acid (HNO_3) and hydrogen peroxide (H_2O_2) oxidization to enhance its adsorption capacity to hexavalent chromium (Cr~(6+)) ion. The adsorption amount and adsorption kinetics of Cr~(6+) ion on ACFs, and the surface chemical groups were investigated. The results showed that the modified ACFs with 1% HNO_3 and 10% H_2O_2 had a better adsorption capacity, respectively. The adsorption amount of ACFs was affected strongly solution pH value, and decreased significantly with increasing of the pH value. The adsorption kinetics indicated that the adsorption rates of Cr~(6+) ion on different modified ACFs were well fitted with the pseudo-second-order kinetic model. After 1% HNO_3 and 10% H_2O_2 modification, respectively, the total acidic oxygen-containing groups on ACFs surface had an increase obviously, which might be enhance the adsorption amount of Cr~(6+) ion on ACFs.