Heteroatomic Modification of Solid-Waste-Based Mesoporous Carbon for Volatile Organic Compound Adsorption

Solid-waste-based activated carbon(AC) was utilized as a carbon source to synthesize a series of carbon-based functional material RAC-X(X = P and S, where P and S denote phosphoric and sulfuric acids, respectively). The toluene adsorption capacities of the regeneration AC(RAC) samples can be significantly improved by adopting the heteroatomic modification strategy. RAC-P and RAC-S have the same specific surface area(1156 m2/g) and similar porous structures. However, they have different toluene adsorption capacities, with 316.22 mg/g for RAC-P and 460.12 mg/g for RAC-S, which are 1.6 and 2.4 times greater than that for RAC. The X-ray photoelectron spectroscopy measurements showed that the increase in the amount of π–π*chemical bond over the AC surface results in the improvement of the toluene adsorption performance. The density functional theory results showed that the S-containing functional groups loaded near the defect sites of RAC-S promote toluene adsorption. Moreover, reusability tests showed that RAC-S still retains 86% of its adsorption activity after four consecutive adsorption–desorption experiments. This indicates that the heteroatomic modification method affords excellent toluene adsorption performance and recycling practicability, which not only is beneficial for achieving the rational utilization of solid waste resources but also provides a practical method for the efficient elimination of volatile organic compounds.