AUTHOR=Xing Rui-Zhi , Li Jia-Xin , Yang Xing-Gui , Chen Ze-Wei , Huang Rong , Chen Zhi-Xuan , Zhou Shun-Gui , Chen Zhi TITLE=Preparation of High-Performance CdS@C Catalyst Using Cd-Enriched Biochar Recycled From Plating Wastewater JOURNAL=Frontiers in Chemistry VOLUME=8 YEAR=2020 URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00140 DOI=10.3389/fchem.2020.00140 ISSN=2296-2646 ABSTRACT=

Biochar is widely used for the adsorptive removal of Cd from water and soil, but the Cd-enriched biochar produced 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.