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1.
Sci Total Environ ; 765: 142794, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33129538

RESUMO

Nonradical persulfate oxidation processes have emerged as a new wastewater treatment method due to production of mild nonradical oxidants, selective oxidation of organic pollutants, and higher tolerance to water matrixes compared with radical persulfate oxidation processes. Since the case of the nonradical activation of peroxydisulfate (PDS) was reported on CuO surface in 2014, nonradical persulfate oxidation processes have been extensively investigated, and much achievement has been made on realization of nonradical persulfate activation processes and understanding of intrinsic reaction mechanism. Therefore, in the review, nonradical pathways and reaction mechanisms for oxidation of various organic pollutants by PDS and peroxymonosulfate (PMS) are overviewed. Five nonradical persulfate oxidation pathways for degradation of organic pollutants are summarized, which include surface activated persulfate, catalysts-free or catalysts mediated electron transfer, 1O2, high-valent metals, and newly derived inorganic oxidants (e.g., HOCl and HCO4-). Among them, the direct oxidation processes by persulfate, nonradical based persulfate activation by inorganic/organic molecules and in electrochemical methods is first overviewed. Moreover, nonradical based persulfate activation mechanisms by metal oxides and carbon materials are further updated. Furthermore, investigation methods of interaction between persulfate and catalyst surface, and nature of reactive species are also discussed in detail. Finally, the future research needs are proposed based on limited understanding on reaction mechanism of nonradical based persulfate activation. The review can offer a comprehensive assessment on nonradical oxidation of organic pollutants by persulfate to fill the knowledge gap and provide better guidance for future research and engineering application of persulfate.

2.
Sci Total Environ ; 712: 136447, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-31931217

RESUMO

The application of MoS2 to enhance Co(II)/peroxymonosulfate (Co(II)/PMS) system for organic pollutants degradation was developed, and the mechanism for pH dependent catalytic activity in the MoS2 co-catalyzed Co(II)/PMS processes was systematically investigated. It was found that MoS2 presented enhancement effect for Co(II)/PMS system in the tested pH range from 4.0 to 7.0, especially at pH 5.5 and 6.0. The pseudo first order reaction rates for Rhodamine B (RhB) degradation in MoS2-Co2+/PMS system at pH 5.5 and 6.0 were 3.2 and 1.8 times that in Co2+/PMS system (Co2+ 2 µmol L-1, PMS 0.2 mmol L-1, MoS2 0.5 g L-1). The redox recycle of Co3+/Co2+ was promoted by Mo(IV) and S(-II) on MoS2 surface and regenerated Co2+ induced homogeneous activation of PMS for the robust production of free radical with the major of hydroxyl radicals. Increasing MoS2 dosage, Co2+ and PMS concentration can linearly raise RhB degradation rate in MoS2-Co(II)/PMS system. Moreover, MoS2 exhibited excellent catalytic and chemical stability in recyclability and reuse for catalytic decontamination in MoS2-Co(II)/PMS system. This work gains new insight into the enhancement effect of MoS2 in the meal ions/PMS system, and provides a high performance wastewater treatment process of Co(II)/PMS at low concentrated Co2+.

3.
J Environ Sci (China) ; 78: 1-12, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30665628

RESUMO

Ibuprofen (IBU), a nonsteroidal anti-inflammatory drug, is becoming an important member of pharmaceuticals and personal care products (PPCPs) as emerging pollutants. To degrade IBU, magnetic Fe3C nanoparticles embedded on N-doped carbon (Fe3C/NC) were prepared as a catalyst by a sol-gel combustion method. As characterized, the Fe3C/NC nanoparticles were composed of a NC nano-sheet and capsulated Fe3C particles on the sheet. The Fe3C/NC nanoparticles were confirmed an efficient catalyst for peroxymonosulfate (PMS) activation to generate sulfate radicals (SO4•-), single oxygen (1O2) and hydroxyl radicals (•OH) toward the degradation of IBU. The added IBU (10 mg/L) was almost completely removed in 30 min by using 0.1 g/L Fe3C/NC and 2 g/L PMS. The catalyst was confirmed to have good ability and excellent reusability through leaching measurements and cycle experiments. A catalytic mechanism was proposed for the catalytic activation of PMS on Fe3C/NC, which involves both Fe3C reactive sites and N-doped carbon matrix as reactive sites in Fe3C/NC. Moreover, the degradation pathway of IBU in the Fe3C/NC-PMS system was proposed according to the detections of degradation intermediates.


Assuntos
Ibuprofeno/química , Modelos Químicos , Poluentes Químicos da Água/química , Carbono/química , Catálise , Compostos Férricos/química , Peróxidos/química
4.
J Hazard Mater ; 364: 59-68, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30339933

RESUMO

Chalcopyrite nanoparticles (CuFeS2 NPs) with abundant surface bonded ferrous were successfully prepared, characterized and used as a catalyst for peroxymonosulfate (PMS) activation and BPA degradation. The effect of reaction parameters such as initial pH, catalyst load, PMS concentration, initial BPA concentration and reaction temperature on BPA degradation in CuFeS2-PMS system was systematically investigated. As a bimetallic sulfide, CuFeS2 exhibits ultra-high activity for PMS activation compared with Cu2S, FeS2, CuFeO2 and Co3O4. It was found that by co-use of 0.1 g L-1 CuFeS2 and 0.3 mmol L-1 PMS, 20 mg L-1 of BPA was almost completely degraded (99.7%) and reached a mineralization rate of 75% within 20 min. The highly catalytic activity of CuFeS2 is closely related to two aspects: one is that S2- in the catalysts promotes the cycling of Fe3+/Fe2+ and Cu2+/Cu+ cycles on the surface, and the other is the synergistic effect of Fe3+/Fe2+ and Cu2+/Cu+ cycles in the PMS activation. These interesting findings shed some new insight on the development of metal sulfides for the oxidative treatment of organic contaminants.

5.
Chemosphere ; 205: 531-539, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29709803

RESUMO

In this work, we report metal ions catalyzed oxidative degradation of three typical fluoroquinolones norfloxacin (NOR), ofloxacin (OFL) and ciprofloxacin (CIP) by using NaBiO3 nanosheets. It was found that variable-valence metal ions such as Cu2+, Fe2+, Mn2+, Ce3+, Ag+ and Co2+ could obviously enhanced degradation of NOR, OFL and CIP by NaBiO3. The pseudo-first-order kinetic rate for the degradation of 20 µmol L-1 NOR by NaBiO3 (2 mmol L-1) in the presence of 0.1 mmol L-1 Cu2+, Fe2+, Mn2+, Ce3+, Ag+ and Co2+ was 0.021, 0.084, 0.019, 0.23, 0.25 and 0.28 min-1, 2.1, 8.4, 19, 23, 25 and 28 times that by NaBiO3 without any metal ions. In comparison, Ca2+ and Fe3+ exhibited no obviously promotive or depressive effect for the degradation of NOR by NaBiO3. Singlet oxygen (1O2) was suggested as the main reactive species from NaBiO3 in the presence of metal ions by electron spin resonance technology and radicals scavenging experiments. The evolution of NaBiO3 was tracked with scanning electron microscope, energy dispersive spectrometer, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy. It was found that the metal ions were embedded into the crystal structure of NaBiO3 through ion-exchange between Na in NaBiO3 and metal ions. In the subsequent step, an electron transformation from lattice oxygen to Bi(V) sites was mediated by embedded variable-valence metal species, resulting in an enhanced generation of 1O2 from the crystal structure of NaBiO3. These results can shed light on the application of NaBiO3 for the organic pollutant decontamination.


Assuntos
Bismuto/química , Ciprofloxacina/química , Metais/química , Norfloxacino/química , Ofloxacino/química , Catálise , Nanoestruturas , Oxirredução , Estresse Oxidativo , Oxigênio/química , Sódio , Difração de Raios X
6.
Molecules ; 21(8)2016 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-27517896

RESUMO

Graphene oxide/Fe3O4 (GO/Fe3O4) nanoparticles were synthesized by an ultrasonic-assisted reverse co-precipitation method, and then horseradish peroxidase (HRP) was covalently immobilized onto GO/Fe3O4 with 1-ethyl-3-(3-dimethyaminopropyl)carbodiimide (EDC) as a cross-linking agent. In order to enhance the phenol removal efficiency and prevent the inactivation of the enzyme, the polyethylene glycol with highly hydrophilicity was added in this reaction, because the adsorption capacity for the polymer by degradation was stronger than the HRP. The results showed that the immobilized enzyme removed over 95% of phenol from aqueous solution. The catalytic condition was extensively optimized among the range of pH, mass ratio of PEG/phenol as well as initial concentration of immobilized enzyme and H2O2. The HRP immobilized on GO/Fe3O4 composite could be easily separated under a magnetic field from the reaction solution and reused.


Assuntos
Clorofenóis/química , Enzimas Imobilizadas , Compostos Férricos/química , Grafite/química , Peroxidase do Rábano Silvestre/química , Fenóis/química , Catálise , Peróxido de Hidrogênio/química , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/ultraestrutura , Oxirredução , Polietilenoglicóis/química , Difração de Raios X
7.
J Hazard Mater ; 317: 686-694, 2016 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-27329789

RESUMO

Microscaled CuFeO2 particles (micro-CuFeO2) were rapidly prepared via a microwave-assisted hydrothermal method and characterized by scanning electron microscopy, X-ray powder diffraction and X-ray photoelectron spectroscopy. It was found that the micro-CuFeO2 was of pure phase and a rhombohedral structure with size in the range of 2.8±0.6µm. The micro-CuFeO2 efficiently catalyzed the activation of peroxymonosulfate (PMS) to generate sulfate radicals (SO4-), causing the fast degradation of carbamazepine (CBZ). The catalytic activity of micro-CuFeO2 was observed to be 6.9 and 25.3 times that of micro-Cu2O and micro-Fe2O3, respectively. The enhanced activity of micro-CuFeO2 for the activation of PMS was confirmed to be attributed to synergistic effect of surface bonded Cu(I) and Fe(III). Sulfate radical was the primary radical species responsible for the CBZ degradation. As a microscaled catalyst, micro-CuFeO2 can be easily recovered by gravity settlement and exhibited improved catalytic stability compared with micro-Cu2O during five successive degradation cycles. Oxidative degradation of CBZ by the couple of PMS/CuFeO2 was effective in the studied actual aqueous environmental systems.


Assuntos
Carbamazepina/análise , Cobre/química , Compostos Ferrosos/química , Peróxidos/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Catálise , Tamanho da Partícula , Reciclagem , Propriedades de Superfície
8.
Chemosphere ; 141: 80-6, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26141554

RESUMO

Bisphenol A (BPA) is a ubiquitous environmental contaminant with endocrine disruption potential. This study explored the efficiency, kinetics, and mechanism of BPA removal from weakly acidic solutions by using NaBiO3 as a source of singlet oxygen. It was observed that the use of NaBiO3 (1gL(-1)) could eliminate almost all (more than 97%) of the added BPA (0.1mmolL(-1)) in solutions at pH 5.0 in 60min. The degradation of BPA followed pseudo-first-order kinetics over the pH range from 3 to 9, and the pseudo-first-order rate constant (k) was dependent on pH, NaBiO3 concentration and the coexisting compounds. As solution pH was decreased from 9 to 3 or NaBiO3 concentration was increased from 0.5 to 2gL(-1), the k value was increased logarithmically. Humic acid and Fe(3+) showed little effect on the BPA removal, but Mn(2+) exhibited exceptionally enhancing effect on the degradation of BPA. The involved reactive species were identified as singlet oxygen by using radical scavenger probes and ESR measurement, and the generated singlet oxygen was confirmed to be generated from the decomposition of NaBiO3 mediated by H(+) ions.


Assuntos
Compostos Benzidrílicos/análise , Bismuto/química , Disruptores Endócrinos/análise , Fenóis/análise , Oxigênio Singlete/química , Sódio/química , Compostos Benzidrílicos/química , Disruptores Endócrinos/química , Substâncias Húmicas/análise , Cinética , Luz , Compostos de Manganês/química , Oxirredução , Fenóis/química , Soluções
9.
Huan Jing Ke Xue ; 36(1): 209-14, 2015 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-25898666

RESUMO

Silver bismuth oxide(BSO) was prepared by a simple ion exchange-coprecipitation method with AgNO3 and NaBiO, .2H2O as raw materials, and then used to oxidatively degrade tetrabromobisphenol A(TBBPA). Effects of the molar ratio of Ag/Bi during BSO preparation and the BSO dosage on the degradation of TBBPA were investigated. The results showed that under the optimized conditions (i.e., the Ag/Bi molar ratio of 1:1, BSO dosage of 1 g x L(-1), 40 mg x L(-1) of TBBPA was completely degraded and the removal of total organic carbon achieved more than 80% within 7 min. The degradation intermediates of TBBPA were identified by ion chromatography, gas chromatograph-mass spectrometer and X-ray photoelectron spectroscopy. The degradation pathway of TBBPA included the debromination, the cleavage of tert-butyl group and the open epoxidation of benzene ring. Based on a quenching study of NaN3, singlet oxygen was proved to play a dominant role in the TBBPA degradation.


Assuntos
Bismuto/química , Óxidos/química , Bifenil Polibromatos/química , Compostos de Prata/química , Corantes , Oxirredução
10.
Huan Jing Ke Xue ; 34(9): 3507-12, 2013 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-24288997

RESUMO

Co-doped BiFeO3 was synthesized by the sol-gel method and used as a catalyst of persulfate (PMS) for the degradation of tetrabromobisphenol A (TBBPA). The effects of the amount of oxidizing agent, catalyst dosage, and the content of doped Co on the degradation of TBBPA were investigated. Under the optimized conditions (doping level of Co to Fe 0.1, dosage 0.5 g x L(-1), PMS concentration 2.5 mmol x L(-1)), the degradation removal of TBBPA within 60 min achieved more than 95%. Catalyst activity showed only a little loss after 4 recycles, and atomic absorption spectrometry (AAS) result showed that few Co ions were leached (0.27% of total Co). The catalyst can be recycled with magnet which shows a good application prospect in the wastewater treatment.


Assuntos
Compostos Ferrosos/química , Bifenil Polibromatos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Catálise , Águas Residuárias/química
11.
J Environ Monit ; 13(11): 3057-63, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21918751

RESUMO

Persulfate can efficiently decolorize azo dyes through oxidizing these compounds, which enabled us to develop a method of rapid spectrophotometric determination of persulfate for monitoring the wastewater treatment on the basis of the oxidation decolorization of azo dyes. Four azo dyes with different molecular structures were investigated as probes, and the influences of operation parameters including reaction time, solution pH, initial dye concentration, and initial concentration of activator Fe(2+) were checked on the determination of persulfate. Under optimum conditions, the decolorization degree of the dyes responded linearly with persulfate concentration for all the four azo dyes, and the linear range and detection limit were found to be 2.0-150 µmol L(-1) and 0.62 µmol L(-1) for rhodamine B, 2.0-100 µmol L(-1) and 0.42 µmol L(-1) for methylene blue, 4.0-150 µmol L(-1) and 0.50 µmol L(-1) for methyl violet, and 20-150 µmol L(-1) and 8.1 µmol L(-1) for orange II. A persulfate treatment of a spiked wastewater sample was satisfactorily monitored with the new method.


Assuntos
Compostos Azo/química , Corantes/química , Monitoramento Ambiental/métodos , Sulfatos/análise , Purificação da Água/métodos , Violeta Genciana/química , Indicadores e Reagentes/química , Azul de Metileno/química , Oxirredução , Rodaminas/química , Espectrofotometria , Sulfatos/química
12.
J Hazard Mater ; 175(1-3): 96-103, 2010 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-19783090

RESUMO

TiO(2) film deposited on glassy carbon electrode surface was prepared via the liquid phase deposition (LPD). The deposited TiO(2) film before and after calcination was characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD). Based on the high photoelectrochemical activity of calcined LPD TiO(2) film, the photoelectrocatalytic degradation of benzotriazole (BTA) was investigated. Compared with the electrochemical oxidation process, direct photolysis or photocatalysis for treatment of BTA, a synergetic photoelectrocatalytic degradation effect was observed using the LPD TiO(2) film-coated electrode. Various factors influencing the photoelectrocatalytic degradation of BTA such as film calcination, applied bias potential, pH value, supporting electrolyte concentration and initial concentration of BTA were investigated. The COD removal for BTA solution was analyzed to evaluate the mineralization of the PEC process. Based on the degradation experimental results, a possible photoelectrocatalytic degradation mechanism for BTA was proposed.


Assuntos
Eletroquímica/métodos , Fotoquímica/métodos , Titânio/química , Triazóis/química , Eliminação de Resíduos Líquidos/métodos , Purificação da Água/métodos , Catálise , Eletrólitos , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura/métodos , Modelos Químicos , Oxigênio/química , Fotólise , Triazóis/análise , Raios Ultravioleta , Difração de Raios X/métodos
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