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Liu T, Zhang B, Li W, Li B, Han Z, Zhang Y, Ding A, Wang S, Ma J, He X. The catalytic oxidation process of atrazine by ozone microbubbles: Bubble formation, ozone mass transfer and hydroxyl radical generation. CHEMOSPHERE 2023; 325:138361. [PMID: 36907491 DOI: 10.1016/j.chemosphere.2023.138361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 02/09/2023] [Accepted: 03/08/2023] [Indexed: 06/18/2023]
Abstract
Ozone microbubbles have received increasing attention since they can produce hydroxyl radical (•OH) to decompose ozone-resistant pollutants. Besides, compared with conventional bubbles, microbubbles have a larger specific surface area and higher mass transfer efficiency. However, the research on the micro-interface reaction mechanism of ozone microbubbles is still relatively scarce. Herein, we systematically studied the stability of microbubbles, ozone mass transfer and atrazine (ATZ) degradation through multifactor analysis. The results revealed that bubble size was dominant in the stability of microbubbles, and gas flow rate played a major role in ozone mass transfer and degradation effects. Besides, the bubble stability accounted for the different effects of pH on ozone mass transfer in two aeration systems. Finally, kinetic models were built and employed to simulate the kinetics of ATZ degradation by •OH. The results revealed that conventional bubbles could produce •OH faster compared with microbubbles under alkaline conditions. These findings shed light on the interfacial reaction mechanisms of ozone microbubbles.
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Affiliation(s)
- Ting Liu
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Bin Zhang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Wenqian Li
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Boda Li
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Ziwen Han
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Yanjie Zhang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - An Ding
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Shutao Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
| | - Xu He
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
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Hyaluronic acid hydrolysis using vacuum ultraviolet TiO 2 photocatalysis combined with an oxygen nanobubble system. Carbohydr Polym 2023; 299:120178. [PMID: 36876793 DOI: 10.1016/j.carbpol.2022.120178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/16/2022] [Accepted: 09/27/2022] [Indexed: 11/23/2022]
Abstract
Advanced technologies for producing high-quality low molecular weight hyaluronic acid (LMW-HA) are required from the perspective of cost-efficiency and biosafety. Here, we report a new LMW-HA production system from high molecular weight HA (HMW-HA) using vacuum ultraviolet TiO2 photocatalysis with an oxygen nanobubble system (VUV-TP-NB). The VUV-TP-NB treatment for 3 h resulted in a satisfactory LMW-HA (approximately 50 kDa measured by GPC) yield with a low endotoxin level. Further, there were no inherent structural changes in the LMW-HA during the oxidative degradation process. Compared with conventional acid and enzyme hydrolysis methods, VUV-TP-NB showed similar degradation degree with viscosity though reduced process time by at least 8-fold. In terms of endotoxin and antioxidant effects, degradation using VUV-TP-NB demonstrated the lowest endotoxin level (0.21 EU/mL) and highest radical scavenging activity. This nanobubble-based photocatalysis system can thus be used to produce biosafe LMW-HA cost-effectively for food, medical, and cosmetics applications.
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