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Vital-Grappin AD, Ariza-Tarazona MC, Luna-Hernández VM, Villarreal-Chiu JF, Hernández-López JM, Siligardi C, Cedillo-González EI. The Role of the Reactive Species Involved in the Photocatalytic Degradation of HDPE Microplastics Using C,N-TiO 2 Powders. Polymers (Basel) 2021; 13:999. [PMID: 33805116 PMCID: PMC8037624 DOI: 10.3390/polym13070999] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/21/2021] [Accepted: 03/22/2021] [Indexed: 12/18/2022] Open
Abstract
Microplastics (MPs) are distributed in a wide range of aquatic and terrestrial ecosystems throughout the planet. They are known to adsorb hazardous substances and can transfer them across the trophic web. To eliminate MPs pollution in an environmentally friendly process, we propose using a photocatalytic process that can easily be implemented in wastewater treatment plants (WWTPs). As photocatalysis involves the formation of reactive species such as holes (h+), electrons (e-), hydroxyl (OH●), and superoxide ion (O2●-) radicals, it is imperative to determine the role of those species in the degradation process to design an effective photocatalytic system. However, for MPs, this information is limited in the literature. Therefore, we present such reactive species' role in the degradation of high-density polyethylene (HDPE) MPs using C,N-TiO2. Tert-butanol, isopropyl alcohol (IPA), Tiron, and Cu(NO3)2 were confirmed as adequate OH●, h+, O2●- and e- scavengers. These results revealed for the first time that the formation of free OH● through the pathways involving the photogenerated e- plays an essential role in the MPs' degradation. Furthermore, the degradation behaviors observed when h+ and O2●- were removed from the reaction system suggest that these species can also perform the initiating step of degradation.
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Affiliation(s)
- Aranza Denisse Vital-Grappin
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza C.P. 66455, Nuevo León, Mexico; (A.D.V.-G.); (V.M.L.-H.); (J.M.H.-L.)
| | - Maria Camila Ariza-Tarazona
- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10/1, 41125 Modena, Italy; (M.C.A.-T.); (C.S.)
| | - Valeria Montserrat Luna-Hernández
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza C.P. 66455, Nuevo León, Mexico; (A.D.V.-G.); (V.M.L.-H.); (J.M.H.-L.)
| | - Juan Francisco Villarreal-Chiu
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza C.P. 66455, Nuevo León, Mexico; (A.D.V.-G.); (V.M.L.-H.); (J.M.H.-L.)
- Centro de Investigación en Biotecnología y Nanotecnología (CIByN), Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Parque de Investigación e Innovación Tecnológica, Km. 10 Autopista al Aeropuerto Internacional Mariano Escobedo, Apodaca 66629, Nuevo León, Mexico
| | - Juan Manuel Hernández-López
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza C.P. 66455, Nuevo León, Mexico; (A.D.V.-G.); (V.M.L.-H.); (J.M.H.-L.)
| | - Cristina Siligardi
- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10/1, 41125 Modena, Italy; (M.C.A.-T.); (C.S.)
| | - Erika Iveth Cedillo-González
- Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Ciudad Universitaria, San Nicolás de los Garza C.P. 66455, Nuevo León, Mexico; (A.D.V.-G.); (V.M.L.-H.); (J.M.H.-L.)
- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10/1, 41125 Modena, Italy; (M.C.A.-T.); (C.S.)
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