Solar Light-Induced Methylene Blue Removal over TiO<sub>2</sub>/AC Composites and Photocatalytic Regeneration
TiO<sub>2</sub>-containing photocatalysts, which combine TiO<sub>2</sub> with carbon-based materials, are promising materials for wastewater treatment due to synergistic photodegradation and adsorption phenomena. In this work, TiO<sub>2</sub>/AC composites were pr...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-11-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/11/11/3016 |
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| author | Fernanda Dalto Iwona Kuźniarska-Biernacka Clara Pereira Elsa Mesquita Olívia Salomé G. P. Soares M. Fernando R. Pereira Maria João Rosa Ana S. Mestre Ana P. Carvalho Cristina Freire |
| author_facet | Fernanda Dalto Iwona Kuźniarska-Biernacka Clara Pereira Elsa Mesquita Olívia Salomé G. P. Soares M. Fernando R. Pereira Maria João Rosa Ana S. Mestre Ana P. Carvalho Cristina Freire |
| author_sort | Fernanda Dalto |
| collection | DOAJ |
| description | TiO<sub>2</sub>-containing photocatalysts, which combine TiO<sub>2</sub> with carbon-based materials, are promising materials for wastewater treatment due to synergistic photodegradation and adsorption phenomena. In this work, TiO<sub>2</sub>/AC composites were produced by the in situ immobilization of TiO<sub>2</sub> nanoparticles over activated carbon (AC) derived from spent coffee grains, using different TiO<sub>2</sub>/AC proportions. The TiO<sub>2</sub>/AC composites were tested as adsorbents (dark) and as photocatalysts in a combined adsorption+photocatalytic process (solar irradiation) for methylene blue (MB) removal from ultrapure water, and from a secondary effluent (SecEf) of an urban wastewater treatment plant. All the materials were characterized by XRD (X-ray powder diffraction), N<sub>2</sub> adsorption–desorption isotherms at −196 °C, SEM (scanning electron microscopy), UV-Vis diffuse reflectance, FTIR (Fourier-transform infrared spectroscopy), TPD (temperature programmed desorption), XPS (X-ray photoelectron spectroscopy) and TGA (thermogravimetric analysis). The TiAC60 (60% C) composite presented the lowest band gap (1.84 eV), while, for TiAC29 (29% C), the value was close to that of bare TiO<sub>2</sub> (3.18 vs. 3.17 eV). Regardless of the material, the solar irradiation improved the percentage of MB discolouration when compared to adsorption in dark conditions. In the case of simultaneous adsorption+photocatalytic assays performed in ultrapure water, TiAC29 presented the fastest MB removal. Nevertheless, both TiAC29 and TiAC60 led to excellent MB removal percentages (96.1–98.1%). UV-induced photoregeneration was a promising strategy to recover the adsorption capacity of the materials, especially for TiAC60 and AC (>95%). When the assays were performed in SecEf, all the materials promoted discolouration percentages close to those obtained in ultrapure water. The bulk water parameters revealed that TiAC60 allowed the removal of a higher amount of MB, associated with the overall improvement of the SecEf quality. |
| first_indexed | 2024-03-10T05:12:54Z |
| format | Article |
| id | doaj.art-7154b5e2df6440ab9ca3d12e09090b5a |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-10T05:12:54Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-7154b5e2df6440ab9ca3d12e09090b5a2023-11-23T00:41:55ZengMDPI AGNanomaterials2079-49912021-11-011111301610.3390/nano11113016Solar Light-Induced Methylene Blue Removal over TiO<sub>2</sub>/AC Composites and Photocatalytic RegenerationFernanda Dalto0Iwona Kuźniarska-Biernacka1Clara Pereira2Elsa Mesquita3Olívia Salomé G. P. Soares4M. Fernando R. Pereira5Maria João Rosa6Ana S. Mestre7Ana P. Carvalho8Cristina Freire9REQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, PortugalREQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, PortugalREQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, PortugalWater Quality and Treatment Laboratory, Urban Water Unit, Hydraulics and Environment Department, LNEC—National Laboratory for Civil Engineering, Av. Brasil 101, 1700-066 Lisboa, PortugalLSRE-LCM, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto, PortugalLSRE-LCM, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto, PortugalWater Quality and Treatment Laboratory, Urban Water Unit, Hydraulics and Environment Department, LNEC—National Laboratory for Civil Engineering, Av. Brasil 101, 1700-066 Lisboa, PortugalCentro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, PortugalCentro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, PortugalREQUIMTE/LAQV, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre s/n, 4169-007 Porto, PortugalTiO<sub>2</sub>-containing photocatalysts, which combine TiO<sub>2</sub> with carbon-based materials, are promising materials for wastewater treatment due to synergistic photodegradation and adsorption phenomena. In this work, TiO<sub>2</sub>/AC composites were produced by the in situ immobilization of TiO<sub>2</sub> nanoparticles over activated carbon (AC) derived from spent coffee grains, using different TiO<sub>2</sub>/AC proportions. The TiO<sub>2</sub>/AC composites were tested as adsorbents (dark) and as photocatalysts in a combined adsorption+photocatalytic process (solar irradiation) for methylene blue (MB) removal from ultrapure water, and from a secondary effluent (SecEf) of an urban wastewater treatment plant. All the materials were characterized by XRD (X-ray powder diffraction), N<sub>2</sub> adsorption–desorption isotherms at −196 °C, SEM (scanning electron microscopy), UV-Vis diffuse reflectance, FTIR (Fourier-transform infrared spectroscopy), TPD (temperature programmed desorption), XPS (X-ray photoelectron spectroscopy) and TGA (thermogravimetric analysis). The TiAC60 (60% C) composite presented the lowest band gap (1.84 eV), while, for TiAC29 (29% C), the value was close to that of bare TiO<sub>2</sub> (3.18 vs. 3.17 eV). Regardless of the material, the solar irradiation improved the percentage of MB discolouration when compared to adsorption in dark conditions. In the case of simultaneous adsorption+photocatalytic assays performed in ultrapure water, TiAC29 presented the fastest MB removal. Nevertheless, both TiAC29 and TiAC60 led to excellent MB removal percentages (96.1–98.1%). UV-induced photoregeneration was a promising strategy to recover the adsorption capacity of the materials, especially for TiAC60 and AC (>95%). When the assays were performed in SecEf, all the materials promoted discolouration percentages close to those obtained in ultrapure water. The bulk water parameters revealed that TiAC60 allowed the removal of a higher amount of MB, associated with the overall improvement of the SecEf quality.https://www.mdpi.com/2079-4991/11/11/3016titanium dioxideactivated carbonnanocompositemethylene blueadsorptionsolar-light induced photocatalysis |
| spellingShingle | Fernanda Dalto Iwona Kuźniarska-Biernacka Clara Pereira Elsa Mesquita Olívia Salomé G. P. Soares M. Fernando R. Pereira Maria João Rosa Ana S. Mestre Ana P. Carvalho Cristina Freire Solar Light-Induced Methylene Blue Removal over TiO<sub>2</sub>/AC Composites and Photocatalytic Regeneration Nanomaterials titanium dioxide activated carbon nanocomposite methylene blue adsorption solar-light induced photocatalysis |
| title | Solar Light-Induced Methylene Blue Removal over TiO<sub>2</sub>/AC Composites and Photocatalytic Regeneration |
| title_full | Solar Light-Induced Methylene Blue Removal over TiO<sub>2</sub>/AC Composites and Photocatalytic Regeneration |
| title_fullStr | Solar Light-Induced Methylene Blue Removal over TiO<sub>2</sub>/AC Composites and Photocatalytic Regeneration |
| title_full_unstemmed | Solar Light-Induced Methylene Blue Removal over TiO<sub>2</sub>/AC Composites and Photocatalytic Regeneration |
| title_short | Solar Light-Induced Methylene Blue Removal over TiO<sub>2</sub>/AC Composites and Photocatalytic Regeneration |
| title_sort | solar light induced methylene blue removal over tio sub 2 sub ac composites and photocatalytic regeneration |
| topic | titanium dioxide activated carbon nanocomposite methylene blue adsorption solar-light induced photocatalysis |
| url | https://www.mdpi.com/2079-4991/11/11/3016 |
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