Drying before microwave-assisted H3PO4 activation to produce highly mesoporous activated carbons

Activated carbons (ACs) were prepared by drying at temperatures of 60-285 °C before microwave-assisted activation to investigate effects of predying on their properties. The predrying affected ACs' P-containing functional groups, structural defects, and textural properties. The mesopore volume, total pore volume, and BET surface area of ACs peaked when predrying temperature was 250 °C (1.05 mL/g, 1.26 mL/g, and 1509 m2/g), mainly because predrying changed microwave activation temperature. The mesopore volume ranked among the highest values ever reported for ACs prepared by microwave activation with P-containing agents; the corresponding mesopore fraction (83.3%) was also large, compared with that of many reported ACs. The drying before microwave activation is an effective strategy to prepare ACs with both superior mesopore volume and high mesopore fraction.