Effect of chlorine treatment on adsorption properties of phenol–formaldehyde resin-derived char

Abstract

The chlorination of phenol–formaldehyde resin-derived char, which was heat-treated at 600°C, was carried out in diluted Cl2 gas at various temperatures. The amount of fixed chlorine on the carbon ranged from 12 to 65 g chlorine per 100 g of carbon, depending on the chlorination temperature. The BET surface area and adsorption capacity of samples heat-treated and dechlorinated after the chlorination increased with the amount of fixed chlorine. The maximum values of the BET surface area and micropore volume were 1130 m2 g−1 and 0.49 cm3 g−1, respectively. The maximum values of the N2, O2 and Ar adsorption capacities were 0.652, 0.605 and 0.595 mmol g−1 at 25°C, respectively. Although the BET surface area and micropore volume were similar to those of conventional activated carbons, the adsorption capacities were remarkably high. This series of treatments, chlorination followed by heat treatment and dechlorination, was found to develop the pore structure and significantly improve the adsorption capacity.