Electrocatalytic dechlorination of 2,4-DCBA using CTAB functionalized Pd/GAC movable granular catalyst: Role of adsorption in catalysis

The CTAB-Pd/GAC catalyst was obtained by functionalizing palladium/granular activated carbon (Pd/GAC) with cetyltrimethylammonium bromide (CTAB), which was used for the electrocatalytic reductive dechlorination of 2,4-dichlorobenzoic acid (2,4-DCBA). The degradation rate of 2,4-DCBA by 40 mg g(-1) CTAB-Pd/GAC was 9.8 x 10(-3) (min(-1) g(-1) Pd), which was 11 folds than that by Pd/GAC (0.9 x 10(-3) min(-1) g(-1) Pd), and the value of q(e, 2,4-DCBA)/q(e), BA was 2.33 as compared to 0.67 for Pd/GAC. The combined result of dechlorination and adsorption experiments suggested that the functionalization by CTAB would enhance the 2,4-DCBA concentration on the surface of CTAB-Pd/GAC, and accelerate the degradation rate. However, the removal efficiency of 2,4-DCBA would decrease when the CTAB load reached 80 mg g(-1), due to the excessive adsorption capacity for dech-lorinated product. Density functional theory (DFT) calculations also proved that CTAB would increase adsorption capacity of catalyst and selective adsorption behavior of 2,4-DCBA, which accelerated the degradation rate of 2,4-DCBA.

Automated summary

The functionalization of Pd/GAC with CTAB enhances the degradation rate of 2,4-DCBA, but excessive CTAB loading can decrease the removal efficiency of dechlorinated products. Density functional theory (DFT) calculations support that CTAB improves the adsorption capacity of the catalyst and selective adsorption behavior of 2,4-DCBA, leading to accelerated degradation rates.