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Duan X, Lu Z, Sun B, Wu S, Qian Z. Efficient utilization of free radicals in advanced oxidation processes under high-gravity environment for disposing pollutants in effluents and gases: A critical review. CHEMOSPHERE 2023:139057. [PMID: 37268234 DOI: 10.1016/j.chemosphere.2023.139057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/16/2023] [Accepted: 05/26/2023] [Indexed: 06/04/2023]
Abstract
Advanced oxidation processes (AOPs) using strongly oxidizing radicals are promising for wastewater treatment and gas purification. Nevertheless, the short half-life of radicals and the limited mass transfer in traditional reactors cause under-utilization of radicals and low pollutant removal efficiency. High-gravity technology (HiGee)-enhanced AOPs (HiGee-AOPs) have been demonstrated a promising way to enhance radical utilization in a rotating packed bed reactor (RPB). Here, we review the potential mechanisms of intensified radical utilization in HiGee-AOPs, structures and performance of RPB, and applications of HiGee in AOPs. The intensification mechanisms are described from three aspects: enhanced generation of radicals by efficient mass transfer, in-situ radical utilization under frequent liquid film renewal, and selective effect on radical utilization due to micromixing in RPB. Based on these mechanisms, we propose a novel High-gravity flow reaction with the essence of efficiency, in-situ, and selectivity in order to better explain the strengthening mechanisms in HiGee-AOPs. HiGee-AOPs possess great potential for treating effluent and gaseous pollutants due to characteristics of High-gravity flow reaction. We discuss the pros and cons of different RPBs and their applications to specific HiGee-AOPs. HiGee improve the following AOPs: (1) facilitate interfacial mass transfer in homogeneous AOPs, (2) enhance mass transfer to expose more catalytically active sites and mass-produce nanocatalysts for heterogeneous AOPs, (3) inhibit bubble accumulation on the electrode surface of electrochemical AOPs, (4) increase the mass transfer between liquid and catalysts in UV-assisted AOPs, (5) improve the micromixing efficiency of ultrasound-based AOPs. Strategies outlined in this paper should inspire further development of HiGee-AOPs.
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Affiliation(s)
- Xiaoxi Duan
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China; Binzhou Institute of Technology, Weiqiao-UCAS Science and Technology Park, Binzhou City, Shandong, 256606, China
| | - ZhiCheng Lu
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China; Binzhou Institute of Technology, Weiqiao-UCAS Science and Technology Park, Binzhou City, Shandong, 256606, China
| | - Baochang Sun
- Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing, 100029, PR China.
| | - Shao Wu
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China; Binzhou Institute of Technology, Weiqiao-UCAS Science and Technology Park, Binzhou City, Shandong, 256606, China
| | - Zhi Qian
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China; Binzhou Institute of Technology, Weiqiao-UCAS Science and Technology Park, Binzhou City, Shandong, 256606, China.
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