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1.
Chemosphere ; 359: 142269, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38719129

RESUMEN

Temperature is a significant operational parameter of denitrifying filter (DF), which affects the microbial activity and the pollutants removal efficiency. This study investigated the influence of temperature on performance of advanced synergistic nitrogen removal (ASNR) of partial-denitrification anammox (PDA) and denitrification, consuming the hydrolytic and oxidation products of refractory organics in the actual secondary effluent (SE) as carbon source. When the test water temperature (TWT) was around 25, 20, 15 and 10 °C, the filtered effluent total nitrogen (TN) was 1.47, 1.70, 2.79 and 5.52 mg/L with the removal rate of 93.38%, 92.25%, 87.33% and 74.87%, and the effluent CODcr was 8.12, 8.45, 10.86 and 12.29 mg/L with the removal rate of 72.41%, 66.17%, 57.35% and 51.87%, respectively. The contribution rate of PDA to TN removal was 60.44%∼66.48%, and 0.77-0.96 mg chemical oxygen demand (CODcr) was actually consumed to remove 1 mg TN. The identified functional bacteria, such as anammox bacteria, manganese oxidizing bacteria (MnOB), hydrolytic bacteria and denitrifying bacteria, demonstrated that TN was removed by the ASNR, and the variation of the functional bacteria along the DF layer revealed the mechanism of the TWT affecting the efficiency of the ASNR. This technique presented a strong adaptability to the variation of the TWT, therefore, it has broad application prospect and superlative application value in advanced nitrogen removal of municipal wastewater.


Asunto(s)
Desnitrificación , Compuestos de Manganeso , Nitrógeno , Óxidos , Temperatura , Eliminación de Residuos Líquidos , Nitrógeno/metabolismo , Óxidos/química , Compuestos de Manganeso/química , Eliminación de Residuos Líquidos/métodos , Filtración/métodos , Bacterias/metabolismo , Reactores Biológicos/microbiología , Contaminantes Químicos del Agua/metabolismo , Contaminantes Químicos del Agua/análisis , Aguas Residuales/química , Oxidación-Reducción , Análisis de la Demanda Biológica de Oxígeno
2.
J Hazard Mater ; 471: 134309, 2024 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-38653133

RESUMEN

This study addresses antibiotic pollution in global water bodies by integrating machine learning and optimization algorithms to develop a novel reverse synthesis strategy for inorganic catalysts. We meticulously analyzed data from 96 studies, ensuring quality through preprocessing steps. Employing the AdaBoost model, we achieved 90.57% accuracy in classification and an R²value of 0.93 in regression, showcasing strong predictive power. A key innovation is the Sparrow Search Algorithm (SSA), which optimizes catalyst selection and experimental setup tailored to specific antibiotics. Empirical experiments validated SSA's efficacy, with degradation rates of 94% for Levofloxacin and 97% for Norfloxacin, aligning closely with predictions within a 2% margin of error. This research advances theoretical understanding and offers practical applications in material science and environmental engineering, significantly enhancing catalyst design efficiency and accuracy through the fusion of advanced machine learning techniques and optimization algorithms.


Asunto(s)
Antibacterianos , Cobalto , Aprendizaje Automático , Óxidos , Contaminantes Químicos del Agua , Cobalto/química , Catálisis , Antibacterianos/química , Contaminantes Químicos del Agua/química , Óxidos/química , Levofloxacino/química , Norfloxacino/química , Algoritmos
3.
J Environ Sci (China) ; 141: 235-248, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38408824

RESUMEN

In this study, the cobalt-nickel layered double hydroxides (CoNi LDH) were synthesized with a variety of Co/Ni mass ratio, as CoxNiy LDHs. In comparison, Co1Ni3 LDH presented the best peroxymonosulfate (PMS) activation efficiency for 2,4-dichlorophenol removal. Meanwhile, CoNi LDH@Nickel foam (CoNi LDH@NF) composite membrane was constructed for enhancing the stability of catalytic performance. Herein, CoNi LDH@NF-PMS system exerted high degradation efficiency of 99.22% within 90 min for 2,4-DCP when [PMS]0 = 0.4 g/L, Co1Ni3 LDH@NF = 2 cm × 2 cm (0.2 g/L), reaction temperature = 298 K. For the surface morphology and structure of the catalyst, it was demonstrated that the CoNi LDH@NF composite membrane possessed abundant cavity structure, good specific surface area and sufficient active sites. Importantly, ·OH, SO4·- and 1O2 played the primary role in the CoNi LDH@NF-PMS system for 2,4-DCP decomposition, which revealed the PMS activation mechanism in CoNi LDH@NF-PMS system. Hence, this study eliminated the stability and adaptability of CoNi LDH@NF composite membrane, proposing a new theoretical basis of PMS heterogeneous catalysts selection.


Asunto(s)
Clorofenoles , Hidróxidos , Níquel , Cobalto , Peróxidos , Fenoles
4.
J Hazard Mater ; 466: 133535, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38271878

RESUMEN

The reuse of activated sludge as a solid waste is severely underutilized due to the limitations of traditional treatment and disposal methods. Given that, the sulfur-containing activated sludge catalyst doped with cobalt (SK-Co(1.0)) was successfully prepared by one-step pyrolysis and calcinated at 850 â„ƒ. The generation of CoSx was successfully characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), indicating that the sulfur inside the sludge was the anchoring site for the externally doped cobalt. Cobalt (Ⅱ) (Co2+), as the main adsorption site for peroxymonosulfate(PMS), formed a complex (SK-Co(1.0)-PMS* ) and created the conditions for the generation of surface radicals. The SK-Co(1.0)/PMS system showed high degradation efficiency and apparent rate constants for Sulfamethoxazole (SMX) (91.56% and 0.187 min-1) and Sulfadiazine (SDZ) (90.73% and 0.047 min-1) within 10 min and 30 min, respectively. Three sites of generation of 1O2, which played a dominant role in the degradation of SMX and SDZ in the SK-Co(1.0)/PMS system, were summarized as:sulfur vacancies (SVs), the Co3+/Co2+ cycles promoted by sulfur(S) species, oxygen-containing functional groups (C-O). The degradation mechanisms and pathways had been thoroughly investigated using DFT calculations. In view of this, a new idea for the resource utilization of activated sludge solid waste was provided and a new strategy for wastewater remediation was proposed.


Asunto(s)
Antibacterianos , Carbón Orgánico , Aguas del Alcantarillado , Cobalto , Residuos Sólidos , Sulfonamidas , Sulfametoxazol , Sulfanilamida , Peróxidos/química , Sulfadiazina , Catálisis
5.
Microsc Res Tech ; 86(11): 1475-1483, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37458113

RESUMEN

Biomass-derived wastes as the additive of nondegradable plastics have been paid more attention due to the ever-growing environmental pollution and energy crisis. Herein, the spent coffee grounds (SCG) have been used as fillers in polypropylene (PP) after the heat treatment to realize its recycling utilization. The effect of the heat treatment atmosphere on the properties of the obtained SCG and SCG/PP composites has been investigated systematically. The results show that the residual coffee oil can be removed more thoroughly under an air atmosphere than under a nitrogen atmosphere at a relatively low cost and an eco-friendly process. The lower residual oil rate of SCG is beneficial to improve the comminution and further enhance the affinity with the PP matrix. The obtained SCG/PP composites hold lower water absorption, higher hydrophobicity, and better mechanical properties, implying their potential applications in the field of food packaging. RESEARCH HIGHLIGHTS: Spent coffee grounds have been used as fillers in PP after the heat treatment. The heat treatment in the air is more favorable for the removal of the coffer oil of SCG. The low residual oil rate in SCG can improve its comminution and affinity with PP. The SCG/PP composites hold excellent performances for food packaging applications.

6.
Chemosphere ; 332: 138911, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37172622

RESUMEN

The designation and fabrication of heterogeneous photocatalyst with superior redox capability is an important technique for emerging pollutants treatment. In this study, we designed the Z-scheme heterojunction of stable 3D-Bi2MoO6@MoO3/PU, which could not only accelerate the migration and separation in photogenerated carriers, but also stabilize the separation rate of photo-generation carriers. In the Bi2MoO6@MoO3/PU photocatalytic system, 88.89% of oxytetracycline (OTC, 10 mg L-1) and 78.25%-84.59% of multiple antibiotics (SDZ, NOR, AMX and CFX, 10 mg L-1) could be decomposed within 20 min under the optimized reaction condition, revealing the superior performance and potential application value. Specifically, the morphology, chemical structure and optical properties detection of Bi2MoO6@MoO3/PU greatly affected the direct Z-scheme electron transferring mode in the p-n type heterojunction. Besides, the ·OH, h+, ·O2- dominated the photoactivation process through ring-opening, dihydroxylation, deamination, decarbonization and demethylation in OTC decomposition. Expectantly, the stability and universality of Bi2MoO6@MoO3/PU composite photocatalyst would further broaden the practical application and demonstrated that the potential of photocatalytic technique in antibiotics pollutants for wastewater remediation.


Asunto(s)
Contaminantes Ambientales , Oxitetraciclina , Antibacterianos , Fotólisis
7.
J Hazard Mater ; 448: 130946, 2023 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-36860075

RESUMEN

In this study, we designed a plain strategy for fabrication of the novel composite ZnO/CuCo2O4 and applied it as catalyst for peroxymonosulfate (PMS) activation to decompose enrofloxacin (ENR) under simulated sunlight. Compared to ZnO and CuCo2O4 alone, the ZnO/CuCo2O4 composite could significantly activate PMS under simulated sunlight, resulting in the generation of more active radicals for ENR degradation. Thus, 89.2 % of ENR could be decomposed over 10 min at natural pH. Furthermore, the influences of the experimental factors, including the catalyst dose, PMS concentration, and initial pH, on ENR degradation were evaluated. Subsequent active radical trapping experiments indicated that sulfate, superoxide, and hydroxyl radicals together with holes (h+) were involved in the degradation of ENR. Notably, the ZnO/CuCo2O4 composite exhibited good stability. Only 10 % decrease in ENR degradation efficiency was observed after four runs. Finally, several reasonable ENR degradation pathways were proposed, and the mechanism of PMS activation was elucidated. This study provides a novel strategy by integrating state-of-the-art material science and advanced oxidation technology for wastewater treatment and environmental remediation.


Asunto(s)
Óxido de Zinc , Enrofloxacina , Peróxidos , Superóxidos
8.
J Hazard Mater ; 448: 130873, 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-36731316

RESUMEN

In recent years, sulfite (S(Ⅳ)), as an alternative to persulfates, has played a crucial role in eliminating antibiotics in wastewater, so there is an urgent need to develop a cheap, environmentally friendly, and effective catalyst. Zero-valent iron (ZVI) has great potential for activated S(Ⅳ) removal of organic pollutants, but its reactivity in water is reduced due to passivation. In this study, a micron-scale iron-carbon composite(mZVI@C-800) prepared via high-temperature calcination was coupled with S(Ⅳ) to degrade metronidazole (MNZ). Under the optimized reaction conditions of mZVI@C-800 dosage of 0.2 g/L and S(Ⅳ) concentration of 0.1 g/L, the MNZ removal rate was up to 81.5 % in acidic and neutral environments. The surface chemical properties of the catalysts were characterized by different analytical techniques, and the corresponding catalytic mechanism was analyzed based on these analytical results. As a result, Fe2+ is the main active site, and ·OH and SO4·- were the dominant active species. The increase in efficiency was attributed to the introduction of carbon to enhance the corrosion of mZVI further releasing more Fe2+. Additionally proposed were the potential response mechanism, the degradation path, and the toxicity change rule. These results demonstrate that the catalytic breakdown of antibiotics in wastewater treatment can be accelerated by the use of the outstanding catalytic material mZVI@C-800.

9.
Environ Sci Pollut Res Int ; 30(18): 53157-53176, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36853542

RESUMEN

Advanced oxidation processes (AOPs) applied to wastewater treatment have become increasingly well developed and the ability of a single technology to remove difficult organic pollutants is limited. One of the main limiting factors is the insufficient variety and quantity of active species generated during the reaction process and catalyst failure. The coupling of the two methods is a practical and effective approach. In this study, different types of semiconductor persulfate (PS) activators, iron molybdate nanoparticles (I-FeMoO4, II-FeMoO4, and III-FeMoO4), were synthesized by simple solvothermal and calcination methods and applied to photo-assisted activation of PS systems. In addition, the relationship between the intrinsic physicochemical and optoelectronic properties of FeMoO4 and the catalytic degradation performance was revealed by a series of characterization tools, and the dominant catalysts were screened. At an unadjusted pH of 4.86, 0.6 g L-1 of PS and 0.4 g L-1 of I-FeMoO4 could achieve efficient degradation of several difficult organic dye contaminants (rhodamine b (Rh B), methylene blue (MB), malachite green (MG), methyl orange (MO), and tartrazine (TTZ)) and other antibiotic contaminants (sulfamethoxazole (SMX), tetracycline (TC), norfloxacin (NOR), and carbamazepine (CBZ)) within 5-60 min. Possible degradation mechanisms in the I-FeMoO4/PS/Light reaction system were suggested by radical trapping experiments and electron paramagnetic resonance (EPR) tests. Recovery tests demonstrated that I-FeMoO4 has good recoverable stability and did not cause secondary pollution. Finally, our study provided a new perspective on the application of coupled wastewater treatment technologies in the practical treatment of organic wastewater.


Asunto(s)
Contaminantes Ambientales , Contaminantes Químicos del Agua , Hierro , Luz Solar , Oxidación-Reducción , Contaminantes Químicos del Agua/análisis
10.
J Biomater Sci Polym Ed ; 34(12): 1643-1659, 2023 08.
Artículo en Inglés | MEDLINE | ID: mdl-36745185

RESUMEN

The similar characteristics of biomaterials to the extracellular matrix are essential for efficient tissue repair through dictating cell behaviors. But the scaffold fabrication with complex shapes and controlled alignment have proven to be a difficult task. Herein, a well-designed three-dimensional silk fibroin scaffold is fabricated through ice template technology. The effect of the silk fibroin protein concentration and the freezing temperature on the microstructure and mechanical properties of scaffolds are investigated systematically. Cells behavior mediated by the obtained silk fibroin scaffolds is detected. The results show that the protein concentration plays a vital role in microstructure and scaffold strength. A well-aligned scaffold can be obtained when silk fibroin solution is kept at 12 wt%, which holds the highest mechanical properties. The pore size can be further adjusted in the range of 5-80 µm by changing the freezing temperature from -60 to -196 °C. The well-oriented scaffold with the appropriate pore size of 10-20 µm has the best ability to guide cell alignment. The resulting scaffolds provide an excellent matrix to guide cells behaviors and have a potential application in tissue engineering.


Asunto(s)
Fibroínas , Fibroínas/química , Andamios del Tejido/química , Proliferación Celular , Ingeniería de Tejidos/métodos , Materiales Biocompatibles/farmacología , Seda/farmacología
11.
Chemosphere ; 311(Pt 1): 137038, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36323385

RESUMEN

Metal organic frameworks-Covalent organic frameworks (MOFs-COFs) nanocomposites could improve the catalytic performance. Herein, a novel nanocomposite catalyst (CC@Co3O4) derived from MOFs-COFs (COF@ZIF-67) was prepared on peroxymonosulfate (PMS) activation for bisphenol A (BPA) and rhodamine B (RhB) degradation. Owing to the Co species, oxygen vacancy (OV), surface hydroxyl (-OH), graphite N and ketone groups (C=O), the CC@Co3O4 exhibited higher catalytic degradation performance and total organic carbon (TOC) for BPA (93.8% and 22.3%) and RhB (98.2% and 82.5%) with a small quantity of catalyst (0.10 g/L) and low concentration of PMS (0.20 g/L) even without pH adjustment. Sulfate radicals (•SO4-), hydroxyl radicals (•OH), single oxygen (1O2), superoxide radicals (•O2-) and electron transfer process were all involved in the degradation of BPA and RhB. Among them, the degradation of BPA and RhB mainly depended on •O2- and 1O2, respectively. Meanwhile, the degradation pathways of BPA and RhB were proposed, and the biotoxicity of the degradation products was evaluated by freshwater chlorella. The results illustrated that the degradation products were environmentally friendly to organisms. In addition, the role of COF in the nanocomposites was also studied. The addition of COF remarkably improved the catalytic performance of CC@Co3O4 due to the faster electron transfer, more graphite N and C=O. Overall, this work may open the door to the development of COF-based catalysts in the field of water pollutant remediation.


Asunto(s)
Chlorella , Contaminantes Ambientales , Grafito , Estructuras Metalorgánicas , Nanocompuestos , Peróxidos/química , Nanocompuestos/química , Oxígeno
12.
Environ Sci Pollut Res Int ; 29(54): 82584-82599, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35752673

RESUMEN

This work studies the degradation of chlortetracycline hydrochloride (CTC) by activated peroxymonosulfate (PMS) with natural manganese sand (NMS). Meanwhile, the NMS was characterized and analyzed by isothermal nitrogen adsorption (BET), energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscope (SEM). It can be induced that NMS material may contain C, O, Al, Si, Fe, Mn, and K, and the proportion of each is 6%, 9%, 13%, 34%, 27%, 5%, and 6%. Critical parameters, including initial pH value, catalyst dosage, and PMS amount, were optimized through response surface methodology. One of the essential significances of response surface methodology (RSM) is the establishment and optimization of the mathematical model to reduce the complexity of the experimental process. It can provide the degree of mutual influence between various factors and optimize the response based on the investigated factors. Results indicated that 81.65% of CTC could be degraded under the optimized conditions of PMS amount 2.02 g/L, the NMS dosage 0.29 g/L and pH 3.87. Also, it shows that NMS is the most powerful of each factor on the degradation efficiency. We proposed the degradation pathways of CTC from the liquid chromatograph-mass spectrometer (LC-MS) results. Therefore, NMS could be applied as an efficient activator of peroxymonosulfate to purify the water and wastewater.


Asunto(s)
Clortetraciclina , Peróxidos , Arena , Purificación del Agua , Clortetraciclina/química , Manganeso , Peróxidos/química , Arena/química , Aguas Residuales/química , Agua/química , Purificación del Agua/métodos
13.
J Biomater Sci Polym Ed ; 33(10): 1308-1323, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35260043

RESUMEN

In this study, silk fibroin nanowhiskers (SNWs) were extracted from natural silk fiber by sulfuric acid hydrolysis with the assistance of ultrasonic wave treatment. The obtained SNWs were mixed with regenerated silk fibroin (RSF) solution to fabricate the SNWs/RSF films. The fabricating SNWs were systematically characterized by using SEM, FTIR, and the SNWs/RSF films were observed by digital camera, PM, etc. The results show that the monodisperse SNWs are evenly distributed in the RSF film. The presence of SNWs in RSF film significantly improves the performances of the film, including the swelling ability, mechanical properties, hydrophilicity, antibacterial efficacy, cytocompatibility. Meanwhile, the SNWs/RSF film can endorse the wound healing efficiency in vivo mice wound site. The proposed techniques for extracting SNWs and fabricating silk fibroin composite film may provide a valuable method for creating an ideal silk-based material for biomedical applications.


Asunto(s)
Bacterias , Materiales Biocompatibles , Fibroínas , Nanoestructuras , Seda , Animales , Bacterias/efectos de los fármacos , Materiales Biocompatibles/síntesis química , Materiales Biocompatibles/farmacología , Fibroínas/síntesis química , Fibroínas/farmacología , Hidrólisis , Ratones , Nanoestructuras/química , Seda/farmacología , Cicatrización de Heridas
14.
J Hazard Mater ; 399: 122966, 2020 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-32516652

RESUMEN

In this study, bimetal layered double hydroxides (CoxCuy-LDHs) containing a carbonate interlayer were synthesized using coprecipitation with a variety of Co/Cu mole ratios. Meanwhile, the corresponding layered double oxides (CoxCuy-LDOs) were prepared as controls. In this study, Electrical energy per order was performed to evaluate economic analysis. Correspondingly, we found that CoxCuy-LDHs possessed a significantly better PMS activation capability than the corresponding metal oxide composite (Co3O4/CuO). Compared with other CoxCuy-LDHs, Co2Cu1 LDH possessed the best PMS activation capability for LOM degradation and the lowest electrical energy per order (EE/O) value during the reaction. Additionally, Co2Cu1 LDH presented an excellent stability and worked over a wide pH range. The hydroxide states of Co(III), Co(II), Cu(I) and Cu(II) were all able to activate PMS, indicating that there were many active sites on the surface of Co2Cu1 LDH. The involvement of radicals in this reaction system was determined via scavenger experiments and electron paramagnetic resonance (EPR). Meanwhile, it's worth noting that a mathematical model was developed to quantify the involvement of SO4- and OH. Subsequently, we determined PMS activation mechanism and LOM decomposition pathway for the PMS/Co2Cu1 LDH system.


Asunto(s)
Fluoroquinolonas , Peróxidos , Óxidos
15.
J Hazard Mater ; 383: 121236, 2020 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-31563046

RESUMEN

Advanced oxidation methods based on photocatalysis and sulfate radicals have attached most interest towards contaminant degradation. However, there are a lack of coupling two methods in the field of pollutant degradation. In the present study, a new Bi2O3/CuNiFe LDHs composite was fabricated and it could efficiently activate persulfate (PS) for lomefloxacin (LOM) decomposition under simulated sunlight, in which 84.6% of LOM (10 mg·L-1) was degraded over 40 min with 0.4 g·L-1 of Bi2O3/CuNiFe LDHs composite and 0.74 mM of PS at natural pH. In addition, the Bi2O3/CuNiFe LDHs composite possessed good reusability and stability at least four runs. Moreover, active radical scavenging experiments indicated that hydroxyl radicals (HO·), sulfate radicals (SO4·-), superoxide radicals (O2·-) and hole (h+) were the main radicals under LOM degradation process. Subsequently, the possible degradation intermediates were determined and the decomposition pathways were put forward. At the same time, activated sludge inhibition experiments were performed to assess the variation of toxicity of LOM and its degradation intermediates during oxidation. Finally, possible reaction mechanism of Bi2O3/CuNiFe LDHs composite for PS activation under simulated sunlight was proposed.


Asunto(s)
Luz Solar , Contaminantes Químicos del Agua , Fluoroquinolonas , Oxidación-Reducción , Contaminantes Químicos del Agua/análisis
16.
Sci Total Environ ; 695: 133963, 2019 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-31756847

RESUMEN

A kind of heterogeneous catalyst, FeMn layered double hydroxide (Fe-Mn-LDH), was fabricated by coprecipitation process and used as PMS activator to degrade a novel organic pollutant octadecylamine (ODA). And the X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microcopy (TEM), Mapping and X-ray photoelectron spectra (XPS) measurements were utilized to characterize the fresh and used Fe-Mn-LDH. After a serious of degradation experiments, it was clearly to see that the activator possessed excellent activation property for PMS and was capable of removing 85% ODA (10 mg·L-1) within 25 min obviously higher than pure PMS. Moreover, the effect of some elements (such as PMS consumption, catalyst consistence and initial pH value), different reaction system and catalyst repeatability on ODA degradation were also explored. And by identification of main radical experiment, SO4- and HO were both confirmed the primary radicals. What's more, extra anion and nature organic matter (NOM) addition experiment displayed that NOM, NO3- and CO32- perform a negative effect on ODA degradation but Cl- could promote it. In addition, repeated experiments and metal leaching after degradation showed good stability of Fe-Mn-LDH. Finally, based on the XPS and Gas Chromatography-Mass Spectrometer (GS-MS) technology, the possible degradation mechanism and pathway were proposed.

17.
J Nanosci Nanotechnol ; 18(12): 8252-8257, 2018 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-30189944

RESUMEN

In this study, nanoscale zero-valent iron decorated graphene oxide (NZVI/GO) composite was fabricated through a reduction process in the presence of sodium borohydride (NaBH4) solution. Subsequently, physicochemical properties of the NZVI/GO composites were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectroscopy (FT-IR) and Raman spectra. Results indicated that Fe species existed in the form of Fe0, which uniformly dispersed on the surface of GO. Furthermore, the performance of NZVI/GO was evaluated by the degradation of tichloroacetic acid (TCAA). TCAA can be rapidly degraded by NZVI/GO. This paper provides a promising strategy to synthesize versatile catalyst which would be potentially applied in sewage treatment to degrade chlorinated organic compounds.

18.
J Nanosci Nanotechnol ; 18(10): 6942-6948, 2018 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-29954514

RESUMEN

In this study, magnetic CoFe2O4 nanoparticles were synthesized by hydrothermal method by using ferric nitrate and cobalt nitrate as raw materials. Subsequently, physicochemical properties of the resulting CoFe2O4 nanoparticles were systematically studied by scanning electron microscope, X-ray diffraction, N2 adsorption/desorption, Fourier transformation infrared spectroscopy and Vibration sample magnetometer measurement. Results indicated that CoFe2O4 nanoparticles with cubic spinel structure possessed an average diameter of 6.9 nm, specific surface area of 103.48 m2 · g-1, saturation magnetization of 54.65 A · m2(emu · g-1) and coercivity of 1.76×104 A · m-1. Furthermore, scavenging experiments revealed that sulfate radicals (.SO-4) was the main active species derived from persulfates, in which 72.3% of diclofenac could be degraded within 30 min treatment. This study provides a promising strategy to synthesize versatile catalyst which would be potentially applied in pharmaceutical wastewater purification.

19.
J Nanosci Nanotechnol ; 18(4): 2304-2309, 2018 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-29442896

RESUMEN

In this study, silver decorated graphene oxide (Ag/GO) composite was fabricated through a reduction process in the presence of potassium borohydride solution. Subsequently, physicochemical properties of the resulting Ag/GO composite were studied by scanning electron microscope, X-ray diffraction, Raman spectra, Fourier transformation infrared spectroscopy and UV-visible diffuse reflectance spectrum. Results indicated that Ag species existed in the form of Ag0, which greatly facilitated the visible light absorbance ability. Furthermore, the performance of Ag/GO was evaluated by PC inactiviation of Escherichia coli under Xenon lamp illumination. It was found that Ag/GO sample could kill the Escherichia coli within 60 min illumination by the non-selective attack of ⋅OH radicals. This study provides a novel and facile strategy to fabricate high-efficient catalyst to kill the bacteria in drinking water treatment.


Asunto(s)
Escherichia coli , Grafito , Plata , Catálisis , Nanocompuestos , Óxidos
20.
J Hazard Mater ; 342: 353-363, 2018 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-28850913

RESUMEN

In the present study, silver phosphate/graphene oxide (Ag3PO4/GO) composite was synthesized by ultrasound-precipitation processes. Afterwards, physicochemical properties of the resulting samples were studied through scanning electron microscope, transmission electron microscope, X-ray diffraction, N2 adsorption/desorption, UV-vis diffuse reflectance spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, surface photovoltage spectroscopy and photoelectrochemical measurements. Results indicated that spherical Ag3PO4 displayed an average diameter of 150 nm and body-centered cubic crystal phase, which was integrated with GO. In addition, the visible light absorbance, charge separation efficiency and lifetime of Ag3PO4 were significantly improved by integration with GO. In addition, Ag3PO4/GO composite was applied to decompose tetrabromosphenol A (TBBPA) in water body. It was found that TBBPA could be completely decomposed within 60 min illumination. Furthermore, several scavenger experiments were conducted to distinguish the contribution of reactive species to the photoctalytic efficiency. Moreover, the enhanced visible light mechanism of Ag3PO4/GO was proposed and discussed. Eventually, several PC decomposition pathways of TBBPA were identified including directly debromination and oxidation, and subsequently further oxidation and hydroxylation processes.

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