Fabrication of highly efficient Bi 2 WO 6 /CuS composite for visible-light photocatalytic removal of organic pollutants
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RESEARCH ARTICLE
Fabrication of highly efficient Bi2WO6/CuS composite for visible-light photocatalytic removal of organic pollutants and Cr(VI) from wastewater Wei Mao1,2, Lixun Zhang1,2, Tianye Wang3,4, Yichen Bai3,4, Yuntao Guan (✉)1,2 1 Guangdong Provincial Engineering Technology Research Center for Urban Water Cycle and Water Environment Safety, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China 2 State Environmental Protection Key Laboratory of Microorganism Application and Risk Control, School of Environment, Tsinghua University, Beijing 100084, China 3 College of Resources and Environment, Jilin Agricultural University, Changchun 130000, China 4 Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases, Changchun 130118, China
HIGHLIGHTS
GRAPHIC ABSTRACT
• A novel Bi2WO6/CuS composite was fabricated by a facile solvothermal method. • This composite efficiently removed organic pollutants and Cr(VI) by photocatalysis. • The DOM could promoted synchronous removal of organic pollutants and Cr(VI). • This composite could be applied at a wide pH range in photocatalytic reactions. • Possible photocatalytic mechanisms of organic pollutants and Cr(VI) were proposed.
ARTICLE INFO Article history:
Received 7 March 2020 Revised 13 August 2020 Accepted 17 August 2020 Available online 8 October 2020 Keywords: Photocatalysis Bi2WO6/CuS Organic pollutants Cr(VI) Synergistic effect
ABSTRACT A visible-light-driven Bi2WO6/CuS p-n heterojunction was fabricated using an easy solvothermal method. The Bi2WO6/CuS exhibited high photocatalytic activity in a mixed system containing rhodamine B (RhB), tetracycline hydrochloride (TCH), and Cr (VI) under natural conditions. Approximately 98.8% of the RhB (10 mg/L), 87.6% of the TCH (10 mg/L) and 95.1% of the Cr(VI) (15 mg/L) were simultaneously removed from a mixed solution within 105 min. The removal efficiencies of TCH and Cr(VI) increased by 12.9% and 20.4%, respectively, in the mixed solution, compared with the single solutions. This is mainly ascribed to the simultaneous consumption electrons and holes, which increases the amount of excited electrons/holes and enhances the separation efficiency of photogenerated electrons and holes. Bi2WO6/CuS can be applied over a wide pH range (2–6) with strong photocatalytic activity for RhB, TCH and Cr(VI). Coexisiting dissolved organic matter in the solution significantly promoted the removal of TCH (from 74.7% to 87.2%) and Cr(VI) (from 75.7% to 99.9%) because it accelerated the separation of electrons and holes by consuming holes as an electron acceptor. Removal mechanisms of RhB, TCH, and Cr(VI) were proposed, Bi2WO6/CuS was formed into a p-n heterojunction to efficiently separate and transfer photoelectrons and holes so as to drive photocatalytic reactions. Specifically, when reducing pollutants (e.g., TCH) and oxidizing pollutants (e.g., Cr(VI)) coexist in wastewater, the p-n heterojunction in Bi2WO6/CuS acts as a “bridge” to shorten the electron transport an
