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1.
Chemosphere ; 238: 124533, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31466004

RESUMO

The activation of persulfate by Fe(II) coupled with hydroxylamine (the HA/Fe(II)/PS system) was highly effective for the degradation of refractory organic contaminants under acidic pH conditions. However, owing to the precipitation of ferric hydroxide and/or the slow reduction from Fe(III) to Fe(II), the HA/Fe(II)/PS system was invalid under neutral and alkaline pH conditions. In this study, it was observed that the degradation of acid orange 7 (AO7) was strongly enhanced over the wide pH range of 2-9 when trace Cu(II) (0.5-5 µM) was spiked into the HA/Fe(II)/PS system. It was evident that Cu(I) was generated via the reduction of Cu(II) by HA in the bimetallic system at both pH 3 and pH 8, and the steady concentration of Fe(II) in the bimetallic system was much higher than that in the HA/Fe(II)/PS system due to the rapid reaction between Fe(III) and Cu(I). Quenching experiments using tert-butyl alcohol, methanol and sodium bromide as the scavengers and electron spin resonance experiments confirmed that the primary reactive species responsible for AO7 degradation were sulfate radical at both pH 3 and pH 8, rather than hydroxyl radical and Cu(III). Nevertheless, sulfate radical was mainly produced by Fe(II)-activated PS at pH 3, while both Cu(I) and Fe(II) made important contributions to the generation of sulfate radical at pH 8. The bimetallic system was also highly effective in degrading other organic contaminants, such as phenol, diclofenac, reactive red 2 and orange G. This study might provide a promising idea based on Fe(II)-activated PS for degrading organic contaminants over a wide pH range.


Assuntos
Compostos Azo/química , Benzenossulfonatos/química , Cobre/química , Hidroxilamina/química , Ferro/química , Sulfatos/química , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio , Radical Hidroxila/química , Oxirredução
2.
J Colloid Interface Sci ; 559: 215-225, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31629275

RESUMO

This work aimed to develop a feasible technology to reuse dead pig biowaste for heavy metals removal, which was first carbonized into pig bone char (PBC) after pyrolysis and further functionalized with amino (NH2) to improve its affinity with heavy metals. The application of PBC after NH2-functionalization for aqueous heavy metals removal was explored, including Pb2+, Cu2+, and different complex Cu(II) species. PBC@SiO2-NH2 showed comparable performance with AC@SiO2-NH2. The adsorption capacity of Pb2+ and Cu2+ by PBC@SiO2-NH2 was 120 and 30 mg g-1, respectively. The NH2 functionalization enhanced the adsorption of complex Cu(II) species, and PBC@SiO2-NH2 exhibited good performance under a wide pH range and coexisting ions. The adsorption of Cu(II)EDTA species with an EDTA/Cu(II) molar ratio of 1.0 by PBC would be enhanced ~3 times and ~6 times after NH2 functionalization and further addition of Fe3+, respectively. The results of EDX, elemental mapping, and XPS confirmed the adsorption of Cu(II) species. The adsorption kinetics, isotherm, and thermodynamics of different Cu(II) species by PBC@SiO2-NH2 were investigated. The regeneration of PBC@SiO2-NH2 was easily performed via acidic wash. These results suggested the application potential of the reuse of biowaste, which could be a promising adsorbent for aqueous heavy metals after specific functionalization.


Assuntos
Aminas/química , Carbono/química , Complexos de Coordenação/química , Cobre/química , Chumbo/química , Adsorção , Animais , Osso e Ossos/química , Cinética , Propriedades de Superfície , Suínos , Termodinâmica , Água , Poluentes Químicos da Água/química
4.
Chemosphere ; 239: 124660, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31505445

RESUMO

The co-precipitation of Fe2+, Cu2+, Zn2+, Cd2+ and Ni2+ were investigated by a mechanochemical processing with CaCO3. The results showed that the synergies of the metal ions led to efficient co-precipitation. The precipitation of Fe2+, Cu2+ and Cd2+ are over 99% and that of Zn2+ and Ni2+ about 98.4% and 93.8%. A significant advantage of the process is that the moisture content of filter residue is much lower (less than 50%) than that using the lime neutralization (more than 80%), offering a potential solution to the sludge problem in wastewater treatment. A further advantage is the neutral pH (about 7.5) obtained by using CaCO3 rather than the highly alkaline pH (about 11) obtained using lime (Ca(OH)2) neutralization method.


Assuntos
Precipitação Fracionada/métodos , Metais Pesados/análise , Esgotos/química , Purificação da Água/métodos , Cádmio/análise , Carbonato de Cálcio/química , Cobre/análise , Dessecação/métodos , Concentração de Íons de Hidrogênio , Ferro/análise , Níquel/análise , Zinco/análise
5.
Chemosphere ; 238: 124675, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524615

RESUMO

A synergistic combination of chloride and copper powder was proposed as a new method to reductively remove arsenic from highly-acidic wastewater with high arsenic content (HAWA). As(III) was reduced to As(0) by copper powder in the presence of chloride and were effectively removed from HAWA. The procedure to remove arsenic was optimized as follows: initial H+ concentration of 5 mol L-1, Cu-to-As molar ratio of 8, Cl-to-As molar ratio of 10, a reaction temperature of 60 °C, copper powder particle size of 68-24 µm, and a stirring speed of 300 r min-1. Under these optimal conditions, the removal rate of arsenic was close to 100%. Kinetics results suggested that the arsenic removal process was controlled by both diffusion and chemical reactions with an apparent activation energy of 29.78 kJ mol-1. The XRD results showed that the removed arsenic in the residue existed primarily in the form of AsCu3 alloy.


Assuntos
Arsênico/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Cloretos/química , Cloro , Cobre/química , Concentração de Íons de Hidrogênio
6.
Chemosphere ; 238: 124683, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524620

RESUMO

The combination of the filtration capacity of zooplankton (e.g. Daphnia) with the nutrient removal capacity of bacterial/algal biofilm in a zooplankton-containing reactor could provide a natural-based alternative for wastewater treatment. A laboratory-scale zooplankton-based reactor was tested at different HRTs resulting in a significant reduction in nutrient concentrations in wastewater when the system was operated at HRTs longer than 1.1 days (preferably of between 2 and 4 days). However, the presence of high concentrations of organic matter (>250 mg COD L-1) in the wastewater inhibited zooplankton activity, limiting its use to tertiary treatment. Therefore, in combination with other natural treatments that can perform primary and secondary treatments, zooplankton may provide a solution for wastewater clarification and nutrient polishing. The effect of a common metal such as copper on the filtration capacity of Daphnia was also evaluated. Daphnia, as well as the whole zooplankton-based reactor, adapted to copper concentrations of up to 70 µg Cu L-1 but an overload of 380 µg Cu L-1 for two-weeks severely affected the biological system.


Assuntos
Bactérias/metabolismo , Reatores Biológicos , Daphnia/metabolismo , Águas Residuárias/química , Zooplâncton/metabolismo , Animais , Biofilmes/crescimento & desenvolvimento , Cobre/análise , Filtração/métodos , Substâncias Húmicas/análise
7.
Chemosphere ; 238: 124690, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524625

RESUMO

Doxorubicin (DOX) originated from users' urine has been an emerging environmental pollutant due to its significant genotoxicity to mankind. Thus, urine source separation is a potential strategy to isolate DOX at a higher concentration and reduce the burden of downstream wastewater treatment. To develop highly efficient, easy separation and retrievable materials for individual patient to conveniently remove DOX from own urine, magnetic Cu3(PO4)2 nanoflowers were prepared through anchoring amino-functionalized magnetic nanoparticles on the Cu3(PO4)2 nanoflowers. Characterizations revealed the magnetic nanoflowers were spherical in shape with a mean size of 15 µm, and porous and hierarchical in structure. Magnetic nanoparticles located the surface of petals. Multibatch experiments were performed to assess the removal performance of DOX from aqueous solution. The magnetic nanoflowers exhibited excellent removal efficiency of DOX under weakly alkaline condition at ambient temperature. Linear and non-linear analyses were carried out to compare the best fitting kinetics and isotherms. Sorption kinetic data best fitted the pseudo-second order model. The Freundlich isotherm explained equilibrium sorption data with R2 = 0.993 higher than that for the Langmuir isotherm. When the pH of synthetic urine was adjusted to weakly alkaline (pH 8.0-9.0), over 95% of DOX (20 mg L-1) was removed by a little of magnetic nanoflowers (50 mg L-1) within 5 min. Meanwhile, the magnetic nanoflowers could be easily separated and recovered from the synthetic urine by a magnet. So, for individual urine source separation strategy, the magnetic nanoflower seems to be an efficient, convenient and inexpensive approach to remove DOX from human urine.


Assuntos
Cobre/química , Doxorrubicina/análise , Magnetismo/métodos , Urina/química , Purificação da Água/métodos , Adsorção , Humanos , Concentração de Íons de Hidrogênio , Fenômenos Magnéticos , Nanopartículas/química , Fosfatos/química , Águas Residuárias/química
8.
Sci Total Environ ; 700: 134470, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31693958

RESUMO

With the increasing demand for beef worldwide, a considerable amount of bovine bone is discharged as solid waste. Therefore, in this study, the physicochemical properties of chars from bovine bones (ribs, scapulae, vertebrae, and legs) and their copper sorption behavior in aqueous solutions were investigated. The bone chars were pyrolyzed at 500 °C and the ash contents were approximately 85.08%, although the leg bone char had significantly higher values. The rib bone char showed a larger specific surface area (172 m2/g), smaller average pore diameter (7.7 nm), and more basic functional groups than the other char types. The maximum sorption capacity varied from 72.53 to 83.71 g/kg, with the rib bone char exhibiting the best adsorption characteristics, followed by the scapulae, vertebrae, and legs. A correlation analysis demonstrated that the adsorption capacity of Cu(II) on bone char is closely related to surface pore characteristics. An adsorption kinetic analysis and physicochemical characterization of the chars indicate that the Cu(II) adsorption mechanism in bovine bone char is primarily surface chemisorption. Based on the different of physicochemical properties and sorption behavior, bone chars pyrolyzed from bovine ribs are most suitable for adsorption-related applications. The results of this study demonstrate the potential for classified utilization of animal bones, including the use of graded bone chars as low-cost adsorbents requiring no chemical pre-treatment.


Assuntos
Osso e Ossos/química , Carvão Vegetal/química , Cobre/química , Adsorção , Animais , Bovinos , Cinética , Modelos Químicos , Resíduos Sólidos
9.
Bioresour Technol ; 298: 122566, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31848043

RESUMO

In this study, a proof-of-concept of bioleaching and recovery of copper (Cu) from E-wastes assisted by direct current (DC) electric field was proved in a bioelectrical reactor. Results showed that 40 mA electric current application could not only significantly shorten the leaching time of Cu from 5 (control) to 3 days with 100% leaching efficiency, but also recover about 97% leached Cu ions within 4 days. DC electric field improved the activity and growth of iron oxidizing bacteria and facilitated Fe2+ oxidation, which resulted in effective leaching of Cu from printed circuit boards (PCBs). The functional Acidithiobacillus was selectively enriched by DC electric field for enhancing the efficiency of bioleaching. At the same time, the leached Cu ions were rapidly electrodeposited on the cathode, achieving the recovery of Cu. Hence, this work provided a novel strategy for metals bioleaching and recovery from E-wastes.


Assuntos
Acidithiobacillus , Resíduo Eletrônico , Cobre , Íons , Metais
10.
Bioresour Technol ; 296: 122339, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31744667

RESUMO

Most metal oxide nanoparticles (NPs) can impact ammonium removal, but the underlying mechanism remains unclear. In this study, high doses of NiO, CuO, ZnO and TiO2 (>1 mg/L) inhibited the ammonium removal performance of Pseudomonas putida Y-9. Interestingly, low levels of CuO NPs (0.1, 0.5 mg/L) and NiO NPs (0.1 mg/L) enhanced ammonium removal efficiency. Moreover, a decrease in Mg2+ levels was significantly positively correlated with ammonium removal efficiency, while negatively correlated with the Ti2+, Zn2+, and Cu2+ release of NPs. Further research on effect of NPs and their corresponding cations on ammonium removal revealed that four NPs affected Mg2+ absorption in Y-9 via different routes, thus impacting NH4+ removal efficiency, i.e., the effect of NiO NPs was caused by itself, TiO2 NPs' impact was solely due to the release Ti4+, while the influence of CuO NPs and ZnO NPs was based on both the particles and released ions.


Assuntos
Compostos de Amônio , Nanopartículas Metálicas , Nanopartículas , Pseudomonas putida , Óxido de Zinco , Cobre , Óxidos
11.
Chemosphere ; 238: 124664, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31472349

RESUMO

Chemosensors have already demonstrated potential for the detection and imaging of metal ions in solutions and biological systems, however, their applications to soil analysis are limited. This study explores the potential of utilizing a chemosensor for the detection of exchangeable Cu2+ in soils via qualitative (solution visual color change) and quantitative (UV-Vis spectrophotometry) approaches. Montmorillonite and kaolin clays were doped with Cu(NO3)2 solutions from 2.5 to 50 mM, and contaminated soil samples were collected from a historic copper mine. The exchangeable Cu2+ was extracted using a standard CaCl2 cation exchange approach, and the Cu2+ concentration in the resulting solutions determined by UV-Vis spectrophotometry, using a chemosensor, and compared to traditional ICP-MS analysis. Analytical results showed that the chemosensor provided a visual response in contaminated soils at concentrations of 25 µM and quantitative detection to concentrations of 1 µM using UV-Vis spectrophotometry. This work demonstrates the first reported chemosensor for exchangeable Cu2+ with application to soil systems.


Assuntos
Colorimetria/métodos , Cobre/análise , Poluentes do Solo/análise , Bentonita/química , Cátions , Argila/química , Mineração , Solo , Espectrofotometria
12.
Chemosphere ; 239: 124760, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31518923

RESUMO

Plant growth and yield are adversely affected by the uptake of toxic hexavalent chromium (Cr(VI)) from soil. The present study describes a facile technique to minimize the uptake of Cr(VI) by chickpea (Cicer arietinum) plant from soil using microporous activated carbon microfiber (ACF). Simultaneously, nano-sized carbon nanofibers (CNFs), grown over the ACF substrate, are used as an efficient carrier of the Cu micronutrient from soil to root, shoot and leaf of the plants. Adsorption, seed germination and plant growth experiments are performed in Cr-stressed medium. The ACF, used as the adsorbent for Cr(VI) in metal-stressed soil (100 mg Cr kg-1 of soil) shows the metal loading of ∼23 mg g-1. Cr(VI) up to 50 mg L-1 concentration causes no stress during germination of chickpea seeds in Murashige and Skoog (MS) medium. A dose of 500 mg-mixture (treatment) per kg-soil increases root and shoot lengths by 52 and 11%, respectively than the control, during plant growth in the metal-stressed soil, attributed to an effective translocation of Cu-CNF through plant cells. Whereas Cr uptake by plant decrease to ∼46%, Cu uptake increase up to ∼120% in comparison to control by the mixture treatment. Protein and chlorophyll contents also significantly increased (*p < 0.05) with the application of treatment. The data clearly show that the mixture of ACF and Cu-CNF can be successfully used for the simultaneous scavenging of Cr(VI) from soil by adsorption over ACF and increased uptake of Cu by plants using the CNFs as the micronutrient carrier.


Assuntos
Cromo/farmacocinética , Cicer/crescimento & desenvolvimento , Nanofibras/química , Poluentes do Solo/farmacocinética , Adsorção , Carvão Vegetal/química , Clorofila/metabolismo , Cromo/isolamento & purificação , Cicer/efeitos dos fármacos , Cicer/metabolismo , Cobre/farmacocinética , Recuperação e Remediação Ambiental/métodos , Germinação , Folhas de Planta , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Solo/química , Poluentes do Solo/isolamento & purificação
13.
Chemosphere ; 239: 124767, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31518925

RESUMO

The present study analyzed the Peruvian scallop Argopecten purpuratus and its food sources for metal and fatty acid concentrations in order to determine spatial and temporal differences. Metals such as copper (Cu), manganese (Mn), and zinc (Zn) in gills and iron (Fe) and Zn in sediments were the most significant explaining factors for spatial differentiations (degree of contamination), while for fatty acids, it was C14:0, C15:0, C16:0 and C18:0 in A. purpuratus' muscle and in its food sources, which explained more temporal differences (El Niño-Southern Oscillation (ENSO) effect). Gills, digestive gland and intestine were the tissues where metal accumulation was the highest in A. purpuratus. Cd in digestive gland was always high, up to ∼250-fold higher than in other tissues, as previously reported in other bioindicator species for metal pollution. Fatty acids were good biomarkers when annual comparisons were performed, while metals when locations were compared. ENSO 2017 played an important role to disentangle A. purpuratus' biological conditions and food sources. A. purpuratus from Paracas locations mostly showed higher metal concentrations in gills and digestive glands, and lower fatty acid concentrations in muscle than those from Sechura and Illescas Reserved Zone.


Assuntos
Monitoramento Ambiental/métodos , Sedimentos Geológicos/análise , Pectinidae/química , Poluentes Químicos da Água/análise , Animais , Aquicultura , Cobre/análise , Cobre/farmacocinética , Biomarcadores Ambientais , Ácidos Graxos/análise , Brânquias/química , Ferro/análise , Ferro/farmacocinética , Manganês/análise , Manganês/farmacocinética , Músculos/química , Pectinidae/metabolismo , Peru , Frutos do Mar/análise , Análise Espaço-Temporal , Distribuição Tecidual , Zinco/análise , Zinco/farmacocinética
14.
Chemosphere ; 239: 124758, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31514009

RESUMO

Trace elements such as copper (Cu) and arsenic (As) are two of the major contaminants and well-known inducers of cognitive deficits and neurobehavioral changes. This study evaluated the immunotoxicity of their individual or combined exposure on different brain regions in chickens. Consequently, nuclear damage and organelle lesions, especially mitochondria were observed under Cu or/and As stress, in which positive regulation of key proteins, dynamin-related protein 1 (Drp1), Cytochrome C (Cyt c), BCL2-associated X (Bax), Caspases 3 and P53 was detected by qRCR and Western blot analyses, indicating disturbed mitochondrial dynamic equilibrium and apoptosis execution. In addition, qRCR analysis confirmed the involvement of cytokines secreted by different populations of helper T cells, indicative of cellular immunity. Gene expression studies showed marked up regulation of Th1/Th17 cytokines along with heat shock protein (HSP) 70, a synergism was noted in co-administration group. Interesting, lower apoptosis index was noted in brainstem compared to cerebrum and cerebellum. An intense immunosuppression and heat shock response against Cu or/and As was also seen in cerebrum and cerebellum but not in brainstem. In conclusion, our study suggests a synergistic neurotoxicity in chickens under Cu and As exposure. These findings provide a basic understanding of mitochondrial abnormality-initiated neuropathology in response to environmental pollutant mixtures, suggesting an adaptive response to the frangibility of the central nerve system.


Assuntos
Arsenitos/toxicidade , Encéfalo/efeitos dos fármacos , Galinhas/imunologia , Cobre/toxicidade , Tolerância Imunológica/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Encéfalo/patologia , Poluentes Ambientais/toxicidade , Resposta ao Choque Térmico/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Masculino , Dinâmica Mitocondrial/efeitos dos fármacos
15.
Chemosphere ; 239: 124748, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31520971

RESUMO

A total of 100 samples were collected from the sediments of a typical copper mining area, south China. Leaching concentrations of selected heavy metals (Ni, Cd, Cu, Pb, Zn, Ba, As, and Hg) were measured to evaluate their distribution patterns and associated health risk. Leaching concentrations of Cu (3.58 ±â€¯1.49 mg/L), Pb (1.50 ±â€¯1.06 mg/L), and Zn (4.04 ±â€¯1.68 mg/L) were significantly higher than the other metals in the samples. By evaluating the spatial heterogeneity, it was found that leaching metal concentrations did not decrease with environmental gradients, mostly caused by diverse distribution in pollution sources. The hazard index and carcinogenic risk indices showed significant risks of human exposure. For public safety, priority governance should be given to the main pollutants (Cd, Cu, Pb, Zn, and As) in sediments. In future studies, the integrated data will be urgently required for local stakeholders to conduct environmental monitoring and remediation scenarios.


Assuntos
Sedimentos Geológicos/análise , Metais Pesados/análise , Mineração , Poluentes do Solo/análise , Poluentes Químicos da Água/toxicidade , Carcinógenos/toxicidade , China , Cobre , Exposição Ambiental/efeitos adversos , Monitoramento Ambiental , Humanos , Metais Pesados/toxicidade , Modelos Teóricos , Saúde Pública , Medição de Risco , Poluentes do Solo/toxicidade , Poluentes Químicos da Água/análise
16.
Chemosphere ; 240: 124942, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31574434

RESUMO

Advanced oxidation processes (AOPs) can degrade heavy metal complexes in wastewater to improve the removal efficiency of metals. However, the influences of AOP treatments on toxicity induced by metal complexes are not well understood. This study compared the toxicity induced by EDTA-copper (Cu) after UV/persulfate (PS) and UV/H2O2 treatments on luminescent bacteria and human HepG2 cells. The results showed that EDTA-Cu complexes decreased Cu toxicity in luminescent bacteria but increased the cytotoxicity in HepG2 cells, indicating species-specific toxicity. The UV/PS and UV/H2O2 treatments under most pH values and [oxidant]/[EDTA-Cu] conditions decreased the toxicity of EDTA-Cu in HepG2 cells but increased the toxicity in luminescent bacteria. When the ratio of [oxidant] to [EDTA-Cu] was 10, low toxicity in treated solutions was observed in both UV treatment processes. The alkaline precipitation treatment had a significant influence on toxicity reduction after UV/PS treatment; however, it had minimal influence on the UV/H2O2 treatment system. The Cu and total organic carbon (TOC) removal efficiency cannot completely explain the results of toxicity assays. EDTA-Cu intermediates might play important roles in changing the toxicity of EDTA-Cu after both UV treatments. This study provides insights into evaluating the treatment efficiency of UV/PS and UV/H2O2 on EDTA-Cu decomplexation.


Assuntos
Complexos de Coordenação/toxicidade , Cobre/toxicidade , Ácido Edético/toxicidade , Peróxido de Hidrogênio/química , Photobacterium/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Transportadores de Cassetes de Ligação de ATP/metabolismo , Linhagem Celular Tumoral , Ácido Edético/química , Células Hep G2 , Humanos , Oxirredução , Raios Ultravioleta , Águas Residuárias/química
17.
Chemosphere ; 238: 124543, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31450109

RESUMO

Nano micro-electrolysis materials (nMETs) have been used to degrade refractory pollutants in batch experiments. The reasonable formation mechanism of nMETs was given through DMXY digital biomicroscopy. Based on the kinetic data of Chlortetracycline (CTC) removal by nMETs in batch experiments, combined with the binomial distribution equation of CTC reduction by nano materials an experimental-scale fluidized bed (ESFB) was designed. The effects of CTC removal performance, pH and iron ion concentration were investigated. Under pure CTC solution environment, the experimental data showed that the average removal rates of CTC by nMET and nano micro-electrolysis material with loading copper (Cu-nMET) are 90.0% and 95.7% in ESFB, respectively. In the presence of nitrate, although the consumption of two kinds of nano-materials increased, their removal efficiencies of pollutants have 2.2%, 0.2% increase compared with the nitrate-free ESFB. At the same time, the CTC degradation pathway and the enhanced removal mechanism by Cu-nMET was proposed. Through microelectrolysis reaction, complexation reaction and the active substances produced, the intermediate products can be degraded completely to NH4+, CO2, H2O and so on. This study aims to provide a theoretical basis for the environmental application of nMETs.


Assuntos
Clortetraciclina/isolamento & purificação , Cobre/química , Eletrólise/métodos , Ferro/química , Nitratos/química , Poluentes Químicos da Água/isolamento & purificação , Clortetraciclina/análise , Clortetraciclina/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
18.
Water Sci Technol ; 80(7): 1249-1256, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31850876

RESUMO

A CuO/ZnO photocatalyst nanocomposite was successfully prepared by co-precipitation and characterized by investigating its chemical and physical properties by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV-vis diffuse reflectance spectroscopy and photoluminescence spectroscopy. The average particle size of CuO/ZnO composite was found to be around 80 nm. The degradation of chlortetracycline hydrochloride pollutants in marine aquaculture wastewater using ZnO and CuO/ZnO was compared and it was found that CuO/ZnO nanocomposite is more efficient than ZnO. The effects of external factors on the photocatalytic effectiveness of nanocomposite were investigated under visible light. Also, the photocatalytic conditions for the degradation of chlortetracycline hydrochloride by the nanocomposite were optimized. Based on both ability and efficiency of degradation, and on the cost and availability, 10:2 molar ratio of Zn2+/Cu2+ and 0.7 g/L nanocomposite, was found to be optimal, in which case the average photocatalytic degradation rate of chlortetracycline hydrochloride reached 91.10%.


Assuntos
Clortetraciclina , Óxido de Zinco , Aquicultura , Catálise , Cobre , Luz , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias
19.
Biochemistry (Mosc) ; 84(11): 1390-1402, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31760925

RESUMO

Terminal oxidases of aerobic respiratory chains catalyze the transfer of electrons from the respiratory substrate, cytochrome c or quinol, to O2 with the formation of two H2O molecules. There are two known families of these membrane oxidoreductases: heme-copper oxidase superfamily and bd-type oxidase family (cytochromes bd) found in prokaryotes only. The redox reaction catalyzed by these enzymes is coupled to the generation of proton motive force used by the cell to synthesize ATP and to perform other useful work. Due to the presence of the proton pump, heme-copper oxidases create the membrane potential with a greater energy efficiency than cytochromes bd. The latter, however, play an important physiological role that enables bacteria, including pathogenic ones, to survive and reproduce under adverse environmental conditions. This review discusses the features of organization and molecular mechanisms of functioning of terminal oxidases from these two families in the light of recent experimental data.


Assuntos
Cobre/química , Complexo de Proteínas da Cadeia de Transporte de Elétrons/metabolismo , Heme/química , Biocatálise , Transporte de Elétrons , Complexo de Proteínas da Cadeia de Transporte de Elétrons/química , Escherichia coli/metabolismo , Geobacillus/metabolismo , Óxido Nítrico/química , Óxido Nítrico/metabolismo , Oxirredução
20.
Water Sci Technol ; 80(5): 827-835, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31746789

RESUMO

Chromium Cr(III) is considered as a toxic pollutant in industrial wastewater. Photocatalytic processes can be used as an efficient method for the treatment of heavy metal wastewaters. This study was conducted to synthesize copper (II) oxide (CuO) with dendrite, leaf and feather morphologies. Synthesized CuO with dendrite and leaf morphologies were characterized by XRD, SEM, and BET/BJH and CuO with feather morphology by XRD, SEM, BET/BJH, FTIR, TEM and DRS techniques. Parameters such as morphology CuO, the contact time (h), and adsorbent dosage (g) in adsorption of Cr(III) and morphology CuO, pH and initial concentration of Cr(III) in the photocatalytic oxidation were investigated. The results demonstrate that CuO feather at 24 h contact time with 0.1 g adsorbent with an adsorption efficiency of 57.24% has the highest efficiency compared to CuO of dendrite and leaf. Oxidation results demonstrate that CuO feather at 2 h with 0.1 g adsorbent dosage and pH = 7 had 89.14% removal efficiency. Also, oxidation results demonstrate that CuO feather at 2 h with 0.1 g adsorbent dosage and pH = 8 had 99.99% removal efficiency, which indicates the high efficiency of the feather.


Assuntos
Cobre , Poluentes Químicos da Água , Adsorção , Cromo , Concentração de Íons de Hidrogênio , Águas Residuárias
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