Preparation and characterization of activated carbon from bamboo by microwave-induced phosphoric acid activation

Bamboo-based activated carbon was prepared with a microwave-induced activation process using phosphoric acid as the activating agent. The effects of various factors such as microwave power, radiation time and phosphoric acid/carbon ratio on the activation have been studied. The optimal activation conditions were determined as: microwave power 350 W, radiation time 20 min and phosphoric acid/carbon ratio 1:1, under which a surface area of 1432 m2/g and a carbon yield of 48% could be reached. The surface chemical properties were characterized with several methods including acid–base titration, point of zero charge (pHpzc) measurement, FTIR spectra and XPS spectra. The results demonstrated the existence of a large amount of acidic groups on the carbon surface, and the species and relative contents of these groups were analyzed in detail. Comparisons with the conventional thermal process demonstrated that the microwave-induced activation process had faster activation rate and higher carbon yield.