Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes
A catalytic ozonation advanced oxidation process (AOP) with a copper(II)-doped carbon dot as catalyst, Cu-CD (using L-cysteine and polyethylene glycol (PEG) as precursors and passivation agents), was developed for textile wastewater treatment (T = 25 °C and pH = 7). Four dyes were analyzed—Methyl Or...
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MDPI AG
2022-04-01
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| 丛编: | Nanomaterials |
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| author | Rita M. F. Cardoso Inês M. F. Cardoso Luís Pinto da Silva Joaquim C. G. Esteves da Silva |
| author_facet | Rita M. F. Cardoso Inês M. F. Cardoso Luís Pinto da Silva Joaquim C. G. Esteves da Silva |
| author_sort | Rita M. F. Cardoso |
| collection | DOAJ |
| description | A catalytic ozonation advanced oxidation process (AOP) with a copper(II)-doped carbon dot as catalyst, Cu-CD (using L-cysteine and polyethylene glycol (PEG) as precursors and passivation agents), was developed for textile wastewater treatment (T = 25 °C and pH = 7). Four dyes were analyzed—Methyl Orange (MO), Orange II sodium salt (O-II), Reactive Black 5 (RB-5) and Remazol Brilliant Blue R (RBB-R), as well as a real effluent from the dying and printing industry. The Cu-CD, with marked catalytic ozonation properties, was successfully synthesized by one-pot hydrothermal procedure with a size of 4.0 nm, a charge of −3.7 mV and a fluorescent quantum yield of 31%. The discoloration of the aqueous dye solutions followed an apparent first-order kinetics with the following rate constants (<i>k</i><sub>ap</sub> in min<sup>−1</sup>): MO, 0.210; O-II, 0.133; RB-5, 0.177; RBB-R, 0.086. In the presence of Cu-CD, the following apparent first-order rate constants were obtained (<i>k</i><sub>ap</sub><sup>c</sup> in min<sup>−1</sup>) with the corresponding increase in the rate constant without catalyst (%Inc): MO, 1.184 (464%); O-II, 1.002 (653%); RB-5, 0.709 (301%); RBB-R, 0.230 (167%). The presence of sodium chloride (at a concentration of 50 g/L) resulted in a marked increase of the discoloration rate of the dye solution due to generation of other radicals, such as chlorine and chlorine oxide, resulting from the reaction of ozone and chloride. Taking into consideration that the real textile effluent under research has a high carbonate concentration (>356 mg/L), which inhibits ozone decomposition, the discoloration first-order rate constants without and with Cu-CD (<i>k</i><sub>ap</sub> = 0.0097 min<sup>−1</sup> and <i>k</i><sub>ap</sub><sup>c</sup> = 0.012 min<sup>−1</sup> (%Inc = 24%), respectively) were relatively small. Apparently, the Cu-CD, the surface of which is covered by a soft and highly hydrated caramelized PEG coating, accelerates the ozone decomposition and dye adsorption, increasing its degradation. |
| first_indexed | 2024-03-09T11:33:45Z |
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| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-09T11:33:45Z |
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| spelling | doaj.art-9f66f43d16b64b51a2bedcb69dcba4c12023-11-30T23:46:05ZengMDPI AGNanomaterials2079-49912022-04-01127121110.3390/nano12071211Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile DyesRita M. F. Cardoso0Inês M. F. Cardoso1Luís Pinto da Silva2Joaquim C. G. Esteves da Silva3Chemistry Research Unit (CIQUP), Institute of Molecular Sciences (IMS)—DGAOT, Faculty of Sciences of University of Porto (FCUP), Rua do Campo Alegre 697, 4169-007 Porto, PortugalChemistry Research Unit (CIQUP), Institute of Molecular Sciences (IMS)—DGAOT, Faculty of Sciences of University of Porto (FCUP), Rua do Campo Alegre 697, 4169-007 Porto, PortugalChemistry Research Unit (CIQUP), Institute of Molecular Sciences (IMS)—DGAOT, Faculty of Sciences of University of Porto (FCUP), Rua do Campo Alegre 697, 4169-007 Porto, PortugalChemistry Research Unit (CIQUP), Institute of Molecular Sciences (IMS)—DGAOT, Faculty of Sciences of University of Porto (FCUP), Rua do Campo Alegre 697, 4169-007 Porto, PortugalA catalytic ozonation advanced oxidation process (AOP) with a copper(II)-doped carbon dot as catalyst, Cu-CD (using L-cysteine and polyethylene glycol (PEG) as precursors and passivation agents), was developed for textile wastewater treatment (T = 25 °C and pH = 7). Four dyes were analyzed—Methyl Orange (MO), Orange II sodium salt (O-II), Reactive Black 5 (RB-5) and Remazol Brilliant Blue R (RBB-R), as well as a real effluent from the dying and printing industry. The Cu-CD, with marked catalytic ozonation properties, was successfully synthesized by one-pot hydrothermal procedure with a size of 4.0 nm, a charge of −3.7 mV and a fluorescent quantum yield of 31%. The discoloration of the aqueous dye solutions followed an apparent first-order kinetics with the following rate constants (<i>k</i><sub>ap</sub> in min<sup>−1</sup>): MO, 0.210; O-II, 0.133; RB-5, 0.177; RBB-R, 0.086. In the presence of Cu-CD, the following apparent first-order rate constants were obtained (<i>k</i><sub>ap</sub><sup>c</sup> in min<sup>−1</sup>) with the corresponding increase in the rate constant without catalyst (%Inc): MO, 1.184 (464%); O-II, 1.002 (653%); RB-5, 0.709 (301%); RBB-R, 0.230 (167%). The presence of sodium chloride (at a concentration of 50 g/L) resulted in a marked increase of the discoloration rate of the dye solution due to generation of other radicals, such as chlorine and chlorine oxide, resulting from the reaction of ozone and chloride. Taking into consideration that the real textile effluent under research has a high carbonate concentration (>356 mg/L), which inhibits ozone decomposition, the discoloration first-order rate constants without and with Cu-CD (<i>k</i><sub>ap</sub> = 0.0097 min<sup>−1</sup> and <i>k</i><sub>ap</sub><sup>c</sup> = 0.012 min<sup>−1</sup> (%Inc = 24%), respectively) were relatively small. Apparently, the Cu-CD, the surface of which is covered by a soft and highly hydrated caramelized PEG coating, accelerates the ozone decomposition and dye adsorption, increasing its degradation.https://www.mdpi.com/2079-4991/12/7/1211textile dyesozonenanomaterialsAOPswastewater treatmentcarbon dots |
| spellingShingle | Rita M. F. Cardoso Inês M. F. Cardoso Luís Pinto da Silva Joaquim C. G. Esteves da Silva Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes Nanomaterials textile dyes ozone nanomaterials AOPs wastewater treatment carbon dots |
| title | Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes |
| title_full | Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes |
| title_fullStr | Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes |
| title_full_unstemmed | Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes |
| title_short | Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes |
| title_sort | copper ii doped carbon dots as catalyst for ozone degradation of textile dyes |
| topic | textile dyes ozone nanomaterials AOPs wastewater treatment carbon dots |
| url | https://www.mdpi.com/2079-4991/12/7/1211 |
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