Effects of the ultrasound-assisted H3PO4 impregnation of sawdust on the properties of activated carbons produced from it

Abstract The effects of the ultrasound-assisted H 3 PO 4 impregnation of sawdust on the pore structure, morphology, surface functional groups, and adsorption capacities for iodine and methylene blue of activated carbons produced from it were investigated. Results showed that ultrasonic impregnation promoted the mass transfer and uptake of H 3 PO 4 , which simultaneously increased specific surface area, pore volumes of micropores, mesopores and ultramicropores, and adsorption capacities for iodine and methylene blue. Long ultrasonic impregnation times were unnecessary. The maximum surface area (1504 m 2 /g) was achieved at a total impregnation time of 45 min with 5 min ultrasound irradiation. Compared with impregnation without the ultrasound treatment, the ultrasonic-assisted impregnation reduced the impregnation time by 85%.