Preparation of High-Performance CdS@C Catalyst Using Cd-Enriched Biochar Recycled From Plating Wastewater
Ruizhi Xing, Jiaxin Li, Xinggui Yang, Ze-Wei Chen, Ze-Wei Chen, Rong Huang, Zhixuan Chen, Zhixuan Chen, Shungui Zhou, Zhi Chen, Zhi Chen
Abstract
Biochar is widely used for the adsorptive removal of Cd from water and soil, but the produced Cd-enriched biochar carries a risk of secondary pollution. In this work, biochar derived from rice straw was used to adsorb Cd from plating wastewater. The Cd-enriched biochar showed a saturated adsorption capacity of about 63.5 mg/g and could be recycled and used in a mesoporous carbon-supported CdS (CdS@C) photocatalyst after pyrolysis carbonization and a hydrothermal reaction. The results demonstrated that the as-prepared CdS@C photocatalyst contained mixed cubic and hexagonal CdS phases, with a considerably lower band gap (2.1 eV) than pure CdS (2.6 eV). CdS@C exhibited an enhanced photocatalytic performance for the degradation of organic dyes under visible light irradiation compared with pure CdS due to its excellent light-harvesting capacity and efficient electron-hole separation. Moreover, the continuous formation of active species (h+, •OH, and O2•−) was responsible for the photodegradation of organic dyes using CdS@C. This work provides new insights for the safe disposal of Cd-enriched wastewater and for improving the economic viability of Cd-contaminated resources by recovering a value-added photocatalyst.