Efficient degradation of VOCs using semi-coke activated carbon loaded 2D Z-scheme g-C3N4-Bi2WO6 photocatalysts composites under visible light irradiation

Abstract

The coal chemical industry generates large quantities of volatile organic compounds (VOCs) and solid wastes. Within this work, porous semi-coke activated carbon (SAC) was produced from solid waste semi-coke (SC) powder. Through loading high performance photocatalysts onto SAC to efficiently degrade VOCs using synergistic effects of adsorption and photocatalysis, acheiving the resourcefulness of solid waste. The specific surface area of the prepared SAC can reach 619.27 m2.g−1, which was effective against the adsorption of VOCs. An one-step hydrothermal method was used to load a 2D Z-scheme g-C3N4-Bi2WO6 (NB) photocatalyst on a semi-coke activated carbon. The 50 wt% NB/SAC material degraded formaldehyde, benzene and toluene up to 93.6%, 84.4% and 78.8% in 130 min under visible light irradiation, being 6.09, 4.55 and 4.75 times higher than that of a single photocatalyst, respectively. The capture experiments showed that hydroxyl radicals (⋅OH) and superoxide radicals (⋅O2–) were the active species in the degradation pathway. The material maintained a high degradation performance of 84.8%, 79.6% and 74.0% even after five cycles. In this study, the mechanism of using SAC as a substrate to enhance performance in photocatalytic degradation was described. The results of this study offered new insights into the resourcefulness of solid waste and the effective degradation of VOCs. It also offered a promising theoretical foundation for the exploitation and utilization of high-performance photocatalysts.