One-pot synthesis of ultrahigh surface area porous carbon from coal tar residue: Characterization and application in phenol removal

Abstract

Coal tar residue (CTR) is a hazardous industrial waste and its appropriate disposal evokes great concerns. In this work, superb surface area porous carbon was synthesized from extracted residue in CTR through one-pot KOH chemical activation and applied for phenol adsorption. Results revealed that micro-mesoporous porous carbon (MPC-3–850) with ultrahigh specific surface area of 5465 m2/g, and multiple oxygen-containing functional groups was synthesized at optimized conditions (mass proportion of KOH/MCTR was 1:3, pyrolysis temperature was 850℃). Adsorption results showed that the optimized absorbent dosage was 2 g/L, and adsorptive equilibrium time was 120 min. Maximum adsorption capacity of MPC-3–850 in experiment was reached higher than 360 mg/g and decreased at elevated temperatures. Near neutral conditions (pH=6–8) and lower co-existing ions (Mg2+, K+, Na+) strength had a slightly effect on adsorption performance. Adsorption process adhered to pseudo-second-order kinetic and Freundlich isotherm models, and was exothermic and spontaneous. The adsorption mechanism included pore filling, van der Waals forces, electron donor-acceptor interaction, hydrogen-bonding interaction, and π-π interaction. MPC-3–850 had a good ability to adsorb phenol in real coke wastewater and excellent adsorption capacity after 4 desorption-adsorption cycles.