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Abstract
The unavailability of clean drinking water is one of the significant health issues in modern times. Industrial dyes are one of the dominant chemicals that make water unfit for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to human health and environmental safety. It is usually released in natural water sources, which becomes a health threat to human beings and living organisms. Hence, there is a need to develop an environmentally friendly, efficient technology for removing MB from wastewater. Photodegradation is an advanced oxidation process widely used for MB removal. It has the advantages of complete mineralization of dye into simple and nontoxic species with the potential to decrease the processing cost. This review provides a tutorial basis for the readers working in the dye degradation research area. We not only covered the basic principles of the process but also provided a wide range of previously published work on advanced photocatalytic systems (single-component and multi-component photocatalysts). Our study has focused on critical parameters that can affect the photodegradation rate of MB, such as photocatalyst type and loading, irradiation reaction time, pH of reaction media, initial concentration of dye, radical scavengers and oxidising agents. The photodegradation mechanism, reaction pathways, intermediate products, and final products of MB are also summarized. An overview of the future perspectives to utilize MB at an industrial scale is also provided. This paper identifies strategies for the development of effective MB photodegradation systems.
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Truong TK, Nguyen TQ, Phuong La HP, Le HV, Van Man T, Cao TM, Van Pham V. Insight into the degradation of p-nitrophenol by visible-light-induced activation of peroxymonosulfate over Ag/ZnO heterojunction. CHEMOSPHERE 2021; 268:129291. [PMID: 33359837 DOI: 10.1016/j.chemosphere.2020.129291] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 11/23/2020] [Accepted: 12/10/2020] [Indexed: 06/12/2023]
Abstract
In this report, the peroxymonosulfate activation over Ag/ZnO heterojunction under visible light (Ag/ZnO/PMS/Vis) for p-nitrophenol (p-NP) contaminant degradation was conducted in detail. Herein, the catalyst dosage was decreased, and the results showed that a dosage of 0.5 g L-1 Ag/ZnO and 4 mM PMS almost completely degraded 30 mg L-1 p-NP after 90 min of irradiation. In addition, the PMS activation mechanism of Ag/ZnO/PMS/Vis system was proposed by investigations of the influence of PMS concentration, the FTIR spectra, UV-Vis spectroscopy, and electrochemical analyses. Additionally, the role of SO4•- in the photocatalytic reaction is determined by a combination of a trapping test using isopropanol and tert-butanol as probe compounds and electron spin resonance (ESR) spectroscopy. This report provides a potential alternative to remove persistent organic contaminants in sewage using PMS incorporated with Ag/ZnO under visible light irradiation.
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Affiliation(s)
- Thao Kim Truong
- Faculty of Materials Science and Technology, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, Ward 4, District 5, Ho Chi Minh City, 700000, Viet Nam; Vietnam National University - Ho Chi Minh City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City, 700000, Viet Nam
| | - Thang Quoc Nguyen
- Faculty of Materials Science and Technology, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, Ward 4, District 5, Ho Chi Minh City, 700000, Viet Nam; Ho Chi Minh City University of Technology (HUTECH), 475A Dien Bien Phu Street, Ward 25, Binh Thanh District, Ho Chi Minh City, 700000, Viet Nam
| | - Ha Phan Phuong La
- Faculty of Materials Science and Technology, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, Ward 4, District 5, Ho Chi Minh City, 700000, Viet Nam; Vietnam National University - Ho Chi Minh City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City, 700000, Viet Nam
| | - Hai Viet Le
- Faculty of Materials Science and Technology, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, Ward 4, District 5, Ho Chi Minh City, 700000, Viet Nam; Vietnam National University - Ho Chi Minh City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City, 700000, Viet Nam
| | - Tran Van Man
- Vietnam National University - Ho Chi Minh City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City, 700000, Viet Nam; Faculty of Chemistry, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, Ward 4, District 5, Ho Chi Minh City, 700000, Viet Nam
| | - Thi Minh Cao
- Ho Chi Minh City University of Technology (HUTECH), 475A Dien Bien Phu Street, Ward 25, Binh Thanh District, Ho Chi Minh City, 700000, Viet Nam
| | - Viet Van Pham
- Faculty of Materials Science and Technology, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, Ward 4, District 5, Ho Chi Minh City, 700000, Viet Nam; Vietnam National University - Ho Chi Minh City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City, 700000, Viet Nam.
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Pretreatment of Grape Stalks by Fungi: Effect on Bioactive Compounds, Fiber Composition, Saccharification Kinetics and Monosaccharides Ratio. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17165900. [PMID: 32823843 PMCID: PMC7459597 DOI: 10.3390/ijerph17165900] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/29/2020] [Accepted: 08/12/2020] [Indexed: 02/06/2023]
Abstract
Grape stalks, an inedible lignocellulosic residue from winemaking and agro-industrial grape juice production, can be valorized as a source of bioactive compounds and as feedstock for the saccharification and bioconversion of soluble sugars. Solid-state fermentation (SSF) by six white-rot fungi was applied as pretreatment. Fiber composition, free radical scavenging activity, four ligninolytic, and three hydrolytic enzyme activities were determined. Saccharification kinetics, yield, and productivity were evaluated and complemented with scanning electron microscopy (SEM), high performance liquid chromatography (HPLC) quantification of monosaccharides, and principal component analysis (PCA). After SSF, the biomass exhibited a drastic free radical scavenging activity decrease and the main enzymes produced were manganese-dependent peroxidase and xylanase. Scanning electron microscopy revealed the erosion of cell walls, and PCA exhibited a negative correlation between saccharification, and neutral detergent fiber and acid detergent lignin. Phlebia rufa pretreated biomass gave the highest sugars yield and productivity, representing a nearly three-fold increase compared to untreated samples. Also, monosaccharides quantification revealed that the 1:1 ratio of glucose to the sum of xylose plus galactose changes to the value of 2:1 after pretreatment. In this work, and for the first time, P. rufa proved to be an effective pretreatment of grape stalks for the saccharification and further bioconversion into value-added chemicals. In addition, lignocellulolytic enzymes were also produced through SSF.
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