Modified Activated Carbon and Its Formaldehyde Purification Performance

Modified activated carbon was prepared by stepwise composite modification in the presence of oxidant and nucleophilic addition reagent. The specific surface area and pore structure of the activated carbon were measured by N₂ adsorption-desorption (BET). Formaldehyde was used as a model pollutant to test the purification performance of the modified activated carbon. The results showed that the stepwise composite modification, first with the oxidant, and then the nucleophilic addition reagent, could significantly improved the fast purification efficiency of activated carbon for formaldehyde. In contrast, the stepwise composite modification, first with the nucleophilic addition reagent, and then with the oxidant, showed an excellent long-term purification effect. After the activated carbon was impregnated first with 2-imidazolidinone followed by treatment with sodium hypochlorite in a stepwise manner, the long-term purification efficiency of formaldehyde with coconut shell and coal-based activated carbon reached 94.2% and 96.2%, respectively.