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Photocatalytic Mechanisms for Peroxymonosulfate Activation through the Removal of Methylene Blue: A Case Study.
Int J Environ Res Public Health. 2019 01 11; 16(2)IJ

Abstract

Industrial activity is one of the most important sources of water pollution. Yearly, tons of non-biodegradable organic pollutants are discharged, at the least, to wastewater treatment plants. However, biological conventional treatments are unable to degrade them. This research assesses the efficiency of photocatalytic activation of peroxymonosulfate (PMS) by two different iron species (FeSO₄ and Fe3+-citrate) and TiO₂. These substances accelerate methylene blue removal by the generation of hydroxyl and sulfate radicals. The required pH and molar ratios PMS:Fe are crucial variables in treatment optimization. The kinetic removal is reduced by the appearance of scavenger reactions in acidic and basic conditions, as well as by the excess of PMS or iron. The best performance is achieved using an Fe3+-citrate as an iron catalyst, reaching the total removal of methylene blue after 15 min of reaction, with a molar ratio of 3.25:1 (1.62 mM of PMS and 0.5 mM Fe3+-citrate). Fe3+-citrate reached higher methylene blue removal than Fe2+ as a consequence of the photolysis of Fe3+-citrate. This photolysis generates H₂O₂ and a superoxide radical, which together with hydroxyl and sulfate radicals from PMS activation attack methylene blue, degrading it twice as fast as Fe2+ (0.092 min-1 with Fe2+ and 0.188 min-1 with Fe3+-citrate). On the other hand, a synergistic effect between PMS and titanium dioxide (TiO₂) was observed (SPMS/TiO2/UV-A = 1.79). This synergistic effect is a consequence of PMS activation by reaction with the free electron on the surface of TiO₂. No differences were observed by changing the molar ratio (1.04:1; 0.26:1 and 0.064:1 PMS:TiO₂), reaching total removal of methylene blue after 80 min of reaction.

Authors+Show Affiliations

Department of Industrial Chemical & Environmental Engineering, Escuela Técnica Superior de Ingenieros Industriales, Universidad Politécnica de Madrid, Calle José Gutiérrez Abascal 2, 28006 Madrid, Spain. jorge.rodriguez.chueca@upm.es.Department of Industrial Chemical & Environmental Engineering, Escuela Técnica Superior de Ingenieros Industriales, Universidad Politécnica de Madrid, Calle José Gutiérrez Abascal 2, 28006 Madrid, Spain. e.alazaro@alumnos.upm.es.Department of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India. dns@civil.iitb.ac.in.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30641995

Citation

Rodríguez-Chueca, Jorge, et al. "Photocatalytic Mechanisms for Peroxymonosulfate Activation Through the Removal of Methylene Blue: a Case Study." International Journal of Environmental Research and Public Health, vol. 16, no. 2, 2019.
Rodríguez-Chueca J, Alonso E, Singh DN. Photocatalytic Mechanisms for Peroxymonosulfate Activation through the Removal of Methylene Blue: A Case Study. Int J Environ Res Public Health. 2019;16(2).
Rodríguez-Chueca, J., Alonso, E., & Singh, D. N. (2019). Photocatalytic Mechanisms for Peroxymonosulfate Activation through the Removal of Methylene Blue: A Case Study. International Journal of Environmental Research and Public Health, 16(2). https://doi.org/10.3390/ijerph16020198
Rodríguez-Chueca J, Alonso E, Singh DN. Photocatalytic Mechanisms for Peroxymonosulfate Activation Through the Removal of Methylene Blue: a Case Study. Int J Environ Res Public Health. 2019 01 11;16(2) PubMed PMID: 30641995.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Photocatalytic Mechanisms for Peroxymonosulfate Activation through the Removal of Methylene Blue: A Case Study. AU - Rodríguez-Chueca,Jorge, AU - Alonso,Esther, AU - Singh,Devendra Narain, Y1 - 2019/01/11/ PY - 2018/12/05/received PY - 2019/01/04/revised PY - 2019/01/08/accepted PY - 2019/1/16/entrez PY - 2019/1/16/pubmed PY - 2019/5/23/medline KW - TiO2 activation KW - dye KW - iron activation KW - peroxymonosulfate KW - sulfate radicals KW - synergistic effect JF - International journal of environmental research and public health JO - Int J Environ Res Public Health VL - 16 IS - 2 N2 - Industrial activity is one of the most important sources of water pollution. Yearly, tons of non-biodegradable organic pollutants are discharged, at the least, to wastewater treatment plants. However, biological conventional treatments are unable to degrade them. This research assesses the efficiency of photocatalytic activation of peroxymonosulfate (PMS) by two different iron species (FeSO₄ and Fe3+-citrate) and TiO₂. These substances accelerate methylene blue removal by the generation of hydroxyl and sulfate radicals. The required pH and molar ratios PMS:Fe are crucial variables in treatment optimization. The kinetic removal is reduced by the appearance of scavenger reactions in acidic and basic conditions, as well as by the excess of PMS or iron. The best performance is achieved using an Fe3+-citrate as an iron catalyst, reaching the total removal of methylene blue after 15 min of reaction, with a molar ratio of 3.25:1 (1.62 mM of PMS and 0.5 mM Fe3+-citrate). Fe3+-citrate reached higher methylene blue removal than Fe2+ as a consequence of the photolysis of Fe3+-citrate. This photolysis generates H₂O₂ and a superoxide radical, which together with hydroxyl and sulfate radicals from PMS activation attack methylene blue, degrading it twice as fast as Fe2+ (0.092 min-1 with Fe2+ and 0.188 min-1 with Fe3+-citrate). On the other hand, a synergistic effect between PMS and titanium dioxide (TiO₂) was observed (SPMS/TiO2/UV-A = 1.79). This synergistic effect is a consequence of PMS activation by reaction with the free electron on the surface of TiO₂. No differences were observed by changing the molar ratio (1.04:1; 0.26:1 and 0.064:1 PMS:TiO₂), reaching total removal of methylene blue after 80 min of reaction. SN - 1660-4601 UR - https://www.unboundmedicine.com/medline/citation/30641995/Photocatalytic_Mechanisms_for_Peroxymonosulfate_Activation_through_the_Removal_of_Methylene_Blue:_A_Case_Study_ L2 - https://www.mdpi.com/resolver?pii=ijerph16020198 DB - PRIME DP - Unbound Medicine ER -