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1.
Chemosphere ; 238: 124572, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31422312

RESUMO

The wastewaters from distilleries of winemaking by-products, a scarcely studied type of vinasse, were treated by white-rot fungal strains from species Irpex lacteus, Ganoderma resinaceum, Trametes versicolor, Phlebia rufa and Bjerkandera adusta. The main objectives of this study were to evaluate fungal performance during vinasse biodegradation, their enzyme patterns and ecotoxicity evolution throughout treatment. Despite all strains were able to promote strong (>80%) dephenolization and reduction of total organic carbon (TOC), P. rufa was less affected by vinasse toxicity and exhibit better decolorization. In batch cultures at 28 °C and pH 4.0, the first phase of P. rufa biodegradation kinetics was characterized by strong metabolic activity with simultaneous depletion of TOC, phenolics and sugars. The main events of second phase are the increase of peroxidases production after the peak of laccase activity, and strong color removal. At the end of treatment, it was observed highly significant (p < 0.001) abatement of pollution parameters (83-100% removal). Since water reclamation and reuse for e.g. crop irrigation is a priority issue, vinasse ecotoxicity was assessed with bioindicators representing three different phylogenetic and trophic levels: a marine bacterium (Aliivibrio fischeri), a freshwater microcrustacean (Daphnia magna) and a dicotyledonous macrophyte (Lepidium sativum). It was observed significant (p < 0.05) reduction of initial vinasse toxicity, as evaluated by these bioindicators, deserving special mention an almost complete phytotoxicity elimination.


Assuntos
Aliivibrio fischeri/crescimento & desenvolvimento , Coriolaceae/metabolismo , Daphnia/crescimento & desenvolvimento , Lepidium sativum/crescimento & desenvolvimento , Polyporales/metabolismo , Trametes/metabolismo , Águas Residuárias/química , Águas Residuárias/toxicidade , Aliivibrio fischeri/metabolismo , Animais , Biodegradação Ambiental , Daphnia/metabolismo , Destilação , Biomarcadores Ambientais/efeitos dos fármacos , Lacase/metabolismo , Lepidium sativum/metabolismo , Peroxidases/metabolismo , Fenóis/metabolismo , Filogenia
2.
Chemosphere ; 238: 124597, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31450106

RESUMO

In this study, we focused on the proportion of particular bacterial groups and changes in microbial community structure in relation to the anammox process parameters and the feeding medium strategy in the Sequencing Batch Reactor (SBR). In order to present an insight into the microbial dynamics while feeding medium shift from synthetic wastewater to landfill leachate, fluorescent in situ hybridization (FISH), Real Time PCR, PCR - DGGE (Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis) and Reverse Transcription PCR-DGGE analysis were used. Feeding medium change has the strongest impact on relative abundance of denitrifiers and representatives of Planctomycetes. The relative abundancy of specific genes for all investigated nitrogen removal bacterial groups dropped after landfill leachate implementation. However, anammox consortium were able to adapt to the new reactor operating conditions and time for adaptation was estimated at the level of 90 days.


Assuntos
Compostos de Amônio/metabolismo , Reatores Biológicos/microbiologia , Planctomycetales/metabolismo , Águas Residuárias/química , Poluentes Químicos da Água/metabolismo , Eletroforese em Gel de Gradiente Desnaturante , Desnitrificação/fisiologia , Hibridização in Situ Fluorescente , Nitrogênio/metabolismo , Oxirredução , Planctomycetales/genética
3.
Chemosphere ; 238: 124573, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31454741

RESUMO

This study investigated the nutrient content and reuse potential of wastewater generated during hydrothermal liquefaction of microalgal biomass. The hydrothermal liquefaction reaction was tested at 270, 300, 330, and 345 °C to determine the effect of temperature on the formation of non-biodegradable dissolved organic nitrogen (nbDON). Total nitrogen, ammonium, color, and toxicity were selected as key characteristics for the reuse of hydrothermal liquefaction wastewater. Results indicated that a higher concentration of nbDON5 (nbDON defined with a 5 day growth assay) and more diverse heterocyclic N-containing organic compounds were associated with greater toxicity as measured by a growth rate assay. For the tested temperature ranges, the total nitrogen content of the hydrothermal liquefaction wastewater slightly decreased from 5020 ±â€¯690 mg L-1 to 4160 ±â€¯120 mg L-1, but the % nbDON5 fraction increased from 57 ±â€¯3 %DON to 96 ±â€¯5 %DON. The temperature of hydrothermal liquefaction reactions can be optimized to maximize carbon conversion and nitrogen recovery.


Assuntos
Chlorella/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Compostos de Nitrogênio/toxicidade , Compostos Orgânicos/toxicidade , Águas Residuárias/toxicidade , Biodegradação Ambiental , Biocombustíveis , Biomassa , Nitrogênio/análise , Compostos de Nitrogênio/metabolismo , Compostos Orgânicos/análise , Temperatura Ambiente , Águas Residuárias/química
4.
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
5.
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
6.
Chemosphere ; 238: 124684, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524621

RESUMO

A novel biochar composite was fabricated via the pyrolysis of distillers grains treated phosphogypsum for phosphate removal from water. Batch adsorption experiments were performed on the adsorption characteristics of phosphate. Effects of pyrolysis temperature, solution pH, the dosage of adsorbent, ambient temperature on phosphate adsorption were also investigated. The results demonstrated that the optimum initial solution pH for phosphate adsorption was 6.0, and high pyrolysis temperature was favorable for phosphate adsorption. The optimal dosage of biochar was 1.25 g L-1. A pseudo-second-order kinetic model can well explain the adsorption kinetics, indicative of the energetically heterogeneous solid surface of the composite. The maximum phosphate adsorption capacity of the phosphogypsum modified biochar obtained from Langmuir isotherm reached 102.4 mg g-1 which was almost five times that of distillers grains biochar alone (21.5 mg g-1). The mechanism is mainly attributed to electrostatic adsorption, surface precipitation and ligand exchange. The ideal adsorption performance indicated that biochar supported phosphogypsum can be used as high-quality adsorbent for phosphate removal in wastewater treatment.


Assuntos
Sulfato de Cálcio/metabolismo , Carvão Vegetal/metabolismo , Grão Comestível/metabolismo , Fosfatos/análise , Fósforo/metabolismo , Águas Residuárias/química , Poluentes Químicos da Água/análise , Adsorção , Destilação , Temperatura Alta , Pirólise
7.
Chemosphere ; 238: 124689, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524624

RESUMO

Pharmaceutical effluents released from industries are accountable to deteriorate the aquatic and soil environment through indirect toxic effects. Microbes are adequately been used to biodegrade pharmaceutical industry wastewater and present study was envisaged to determine biodegradation of pharmaceutical effluent by Micrococcus yunnanensis. The strain showed 42.82% COD (Chemical oxygen demand) reduction before optimization. After applying Taguchi's L8 array as an optimization technique, the biodegradation rate was enhanced by 82.95% at optimum conditions (dextrose- 0.15%, peptone 0.1%, inoculum size 4% (wv-1), rpm 200, pH 8 at 25 °C) within 6 h. The confirmation of pharmaceuticals degradation was done by 1H NMR (Nuclear magnetic resonance) studies followed by elucidation of transformation pathways of probable drugs in the effluent through Q-Tof-MS (Quadrupole Time of Flight- Mass Spectrometry). The cytotoxicity evaluation of treated and untreated wastewater was analyzed on Human Embryonic Kidney (HEK 293) cells using Alamar Blue assay, which showed significant variance.


Assuntos
Biodegradação Ambiental , Resíduos Industriais/análise , Micrococcus/metabolismo , Preparações Farmacêuticas/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Análise da Demanda Biológica de Oxigênio , Linhagem Celular , Indústria Farmacêutica , Células HEK293 , Humanos
8.
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
9.
Chemosphere ; 238: 124693, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524627

RESUMO

In this work, self-assembled gels were prepared with exfoliated montmorillonite and chitosan (EMCG) as the adsorbent for removing methyl orange (MO) from water in absence and presence of methylene blue (MB). Several techniques including scanning electron microscope (SEM), zeta potential, fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used for the characterization of the EMCG before and after removal of MO. The EMCG performed well in the removal of MO attributing to the electrostatic attraction, cation exchange and hydrogen bond. The adsorption behaviors were followed pseudo-second-order and Langmuir isotherm. More surprisingly, the maximum adsorption capacity of MO was obviously enhanced in the presence of MB that it increased from 545 mg g-1 (absence of MB) to 1060 mg g-1 with the shielding effect of MB on EMCG which allowed MO and MB to alternately arrange at the adsorption sites. This finding of the synergistic effect between the two dyes on the proposed composite opens up new vistas to imagine the enhanced purification of the wastewater with multiple dyes co-existed using the multifunctional adsorbents.


Assuntos
Compostos Azo/análise , Bentonita/química , Quitosana/química , Azul de Metileno/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Compostos Azo/química , Corantes/química , Géis , Espectroscopia Fotoeletrônica , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias/química , Poluentes Químicos da Água/química
10.
Chemosphere ; 238: 124680, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31545213

RESUMO

The antibiotic resistance induced by the release of antibiotics to the environment has urged research towards developing effective technologies for antibiotic removal from wastewater. Traditional technologies such as activated sludge processes are not effective for antibiotic removal. Recently, microalgae-based technology has been explored as a potential alternative for the treatment of wastewater containing antibiotics by adsorption, accumulation, biodegradation, photodegradation, and hydrolysis. In this review, the toxicities of antibiotics on microalgae, the mechanisms of antibiotic removal by microalgae, and the integration of microalgae with other technologies such as ultraviolet irradiation (photocatalysis), advanced oxidation, and complementary microorganism degradation for antibiotic removal were discussed. The limitations of current microalgae-based technology and future research needs were also discussed.


Assuntos
Antibacterianos/análise , Antibacterianos/toxicidade , Microalgas/efeitos dos fármacos , Microalgas/metabolismo , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias/química , Adsorção , Biodegradação Ambiental , Resistência Microbiana a Medicamentos/fisiologia , Hidrólise , Fotólise , Esgotos/química , Raios Ultravioleta
11.
Chemosphere ; 238: 124854, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31549676

RESUMO

This work focusses on the production of hydrogen peroxide and in the removal of bromacil by the electro-Fenton process using two different electrochemical cells: mixed tank cell (MTC) and flow-through cell (FTC). Both cells use boron doped diamond (BDD) as anode and carbon felt as cathode to promote the formation of hydrogen peroxide. In the case of the MTC, two surface area ratios, Acathode/Aanode, have been used. Results show that the H2O2 produced by MTC and FTCPSC increases with the time until a stabilization state. For the FTCPSC, the average hydrogen peroxide concentration produced increases progressively with the current, while for MTC the maximum values are found in applying very low current densities. In addition, the FTCPSC provides higher concentrations of hydrogen peroxide for the same current density applied. Regarding the MTC, it can be stated that the higher the area of the cathode, the higher is the amount of H2O2 produced and the lower is the cell voltage (because of a more efficient current lines distribution). The initial oxidation of bromacil is very efficiently attained being rapidly depleted from wastewater. However, the higher production of hydrogen peroxide obtained by the FTCPSC cell does not reflect on a better performance of the electro-Fenton process. Thus, bromacil is better mineralized using the MTC cell with the lowest cathode area. This observation has been explained because larger concentrations of produced hydrogen peroxide seems to benefit the oxidation of intermediates and not the mineralization.


Assuntos
Bromouracila/análogos & derivados , Diamante/química , Peróxido de Hidrogênio/síntese química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Boro/química , Bromouracila/análise , Carbono/química , Condutividade Elétrica , Ferro/química , Oxirredução
12.
Sci Total Environ ; 700: 134469, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31693961

RESUMO

The presence of contaminants of emerging concern (CECs), such as antibiotics, antimicrobial disinfectants, nonprescription drugs, personal care products, pharmaceuticals, and steroids, in water resources can impact aquatic and human health. A large portion of the CECs entering regional wastewater treatment plants originate from hospitals. The purposes of this study were to conduct exploratory analytical work to characterize two hospital wastewaters and to evaluate treatment of CECs at hospitals before dilution with domestic wastewater. A 24-h batch reaction with biogenic manganese oxides coated onto coir fiber was used to treat the wastewaters. Organic contaminants in the wastewaters were concentrated by both liquid-liquid extraction (LLE) and solid-phase extraction (SPE). LLE extracts were analyzed by Comprehensive Two-Dimensional Gas Chromatography/Time-of-Flight Mass Spectrometry (GC × GC-TOFMS) while SPE extracts were analyzedby UltraHigh Performance Liquid Chromatography/Time-of-Flight Mass Spectrometry (UHPLC-TOFMS). Fifty-two organic micropollutants were detected (26 by GC × GC-TOFMS, 25 by UHPLC-TOFMS, 1 by both) in the wastewaters, while 29 were removed by >90% and six were degraded by <50% after treatment. Control experiments revealed that sorption to coir fiber and oxidation by manganese oxides were the primary contaminant removal mechanisms. Both the LLE and SPE extracts were used to evaluate potential human toxicity of the hospital wastewaters before and after treatment. Twenty-eight human cell-based bioreceptor assays were used to screen the wastewaters, and secondary tests were run to quantify toxicity equivalents to activated receptors. The wastewaters initially contained organic micropollutants that strongly activated the Androgen Receptor, Estrogen Receptor ß, and the Mineralocorticoid Receptor but no bioactive compounds were detected after treatment. Point-of-entry treatment of hospital wastewater should reduce bioactive compounds from entering the environment.


Assuntos
Monitoramento Ambiental , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Cromatografia Gasosa-Espectrometria de Massas , Hospitais , Extração Líquido-Líquido , Extração em Fase Sólida , Espectrometria de Massas em Tandem , Águas Residuárias
13.
Sci Total Environ ; 700: 134414, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31698277

RESUMO

This study synthesized magnetic greigite/biochar composites (MGBs) by a solvothermal method and tested their ability to remove Cr(VI) from heavy metal-polluted wastewater. X-ray diffraction (XRD), Fourier transformed infrared spectrometry (FT-IR) and scanning electron microscopy (SEM) revealed that magnetic greigite (Fe3S4) flakes were aggregated and anchored to the biochar surface, resulting in more active sites than pristine biochar. Maximum Cr removal efficiency and capacity of MGB-30 (greigite/biochar = 30%) at an initial Cr(VI) concentration of 20 mg/L were 93% and 23.25 mg/g, respectively. A pseudo-first-order kinetic model was determined for the Cr(VI) removal process and the Cr(VI) removal rate constants were highly dependent on the mass ratios of Fe3S4 loaded on biochar, initial MGB and Cr(VI) concentrations and solution pH. X-ray photoelectron spectroscopy (XPS) and flame atomic absorption spectrometric (FAAS) analysis demonstrated that Cr(VI) was preferentially adsorbed on MGBs and subsequently reduced to Cr(III) by MGBs. Electron paramagnetic resonance (EPR) spectroscopy and iron redox transformations revealed that the Cr(VI) removal enhancement was attributed to efficient surface Fe(III)/Fe(II) cycling via electron transfer with the persistent free radicals (PFRs) of biochar. These novel findings provide new insights into the Fe(III)/Fe(II) cycle induced by biochar and the prospects of using magnetic greigite/biochar composites for remediation of Cr(VI)-rich wastewaters.


Assuntos
Cromo/química , Ferro/química , Sulfetos/química , Poluentes Químicos da Água/química , Adsorção , Carvão Vegetal , Cromo/análise , Compostos Férricos/química , Fenômenos Magnéticos , Magnetismo , Espectroscopia de Infravermelho com Transformada de Fourier , Eliminação de Resíduos Líquidos , Águas Residuárias , Poluentes Químicos da Água/análise
14.
Chemosphere ; 238: 124599, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31454743

RESUMO

In this study, an Fe(Ⅱ)/S(IV) system was designed for the degradation of chloramphenicol (CAP). The pseudo-first-order rate constants for CAP degradation under typical conditions with and without air purging were investigated. The greatly enhanced rate of 0.0099 min-1 with air purging compared with 0.0006 min-1 with no air purging indicated that aeration was significant to the degradation of CAP in Fe(Ⅱ)/S(Ⅳ) system. Radical scavenging experiments revealed that SO4- was the primary oxidant generated from the activation of S(IV) with Fe(II), accounting for around 70% of degradation under weak acidic and neutral conditions. Increasing Fe(II) and S(IV) doses promoted the degradation of CAP, whereas the overdose of them led to a decreased degradation rate by scavenging radicals. Owing to the participation of oxygen in the formation of ferric sulfite complex and SO5-, the increase of dissolved oxygen improved the removal efficiency of CAP. The removal efficiency of CAP was also found to be pH dependent, decreasing from acid condition (initial pH = 4) to basic condition (initial pH = 8). The presence of coexisting anions and water matrix was found inhibiting CAP degradation in Fe(Ⅱ)/S(Ⅳ) system. This work provides an understanding on the working mechanism and possible applications of Fe(Ⅱ)/S(Ⅳ) system in organic compound degradation in wastewater.


Assuntos
Cloranfenicol/metabolismo , Compostos Orgânicos/química , Sulfitos/química , Poluentes Químicos da Água/análise , Ferro/química , Oxirredução , Oxigênio , Águas Residuárias/química
15.
Chemosphere ; 238: 124539, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31470310

RESUMO

The performance and microbial community structure of anaerobic dynamic membrane bioreactor (AnDMBR) treating textile wastewater was investigated. The reactor showed excellent soluble COD and color removal of 98.5% and >97.5%, respectively. Dynamic membrane layer grown over the 3D printed dynamic membrane support showed decent rejection for high molecular weight compounds (>20 kDa); and the total suspended solid rejection by the dynamic layer was >98.8%. Gel permeation chromatography analysis of extracellular polymeric substance (EPS) and effluent samples revealed EPS accounted for more than 76.7% of low molecular weight fractions (<20 kDa) that end up in the effluent. Higher applied flux facilitated the rapid formation dynamic layer which enabled a satisfactory effluent quality. Microbial community analysis revealed that during the operation the archaeal community was relatively stable while obvious changes took place in the bacterial community. Introduction of dye Remazol Brilliant Blue R (RBBR) to the AnDMBR increased the abundances of phyla of Proteobacteria and Spirochaetae whereas fractions of Firmicutes and Euryarchaeota decreased obviously. Furthermore, relative stable abundances of phyla Aminicenantes, Bacteroidetes, Thermotogae and Chloroflexi among the top six phyla detected in the system ensured a healthy anaerobic degradation environment for RBBR wastewater treatment.


Assuntos
Antraquinonas/isolamento & purificação , Antraquinonas/metabolismo , Reatores Biológicos/microbiologia , Membranas Artificiais , Têxteis , Águas Residuárias/química , Anaerobiose , Corantes/isolamento & purificação , Corantes/metabolismo , Matriz Extracelular de Substâncias Poliméricas/microbiologia , Proteobactérias/metabolismo , Spirochaeta/metabolismo , Poluentes Químicos da Água/isolamento & purificação , Poluentes Químicos da Água/metabolismo
16.
Chemosphere ; 240: 124893, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31550585

RESUMO

Water pollution with heavy metals is a global problem. Using microbial adsorbents to remediate water bodies contaminated with heavy metals has been garnering considerable attention. In this study, a cadmium (Cd2+)-resistant bacterium, isolated from soil polluted with heavy metals, was characterized as Pseudomonas sp. 375 based on its biochemical characteristics and 16S rRNA gene. The minimum inhibitory concentration (MIC) of Cd2+ for strain 375 was 6 mM. We evaluated the effects of different parameters, such as initial pH, contact time, and initial Cd2+ concentration, on Cd2+ uptake. The data acquired using nonliving biomass were fitted to a Langmuir isotherm model; however, the Freundlich isotherm model showed better fit for data acquired using living biomass. The maximum biosorption capacities were 92.59 mg g-1 and 63.29 mg g-1 for living and nonliving cells, respectively. The kinetics of biosorption was described using a pseudo-second order kinetic model. The tightly bound Cd on the cell wall played a major role in Cd2+ adsorption for both biosorbents. SEM-EDX analysis also showed that Cd2+ was bound to the cell wall. FTIR spectral analysis showed that -CH2, -OH, -SO3, CO, N-H, C-N, phosphate, or sulfate functional groups were the main functional sites for the binding of Cd2+ ions. Effectively Cd2+ removal from Cd2+ contaminated water suggested Pseudomonas sp. 375 was an (a) inexpensive, effective, and promising biosorbent that can be used for bioremediation Cd2+-contaminated wastewater.


Assuntos
Cádmio/metabolismo , Pseudomonas/metabolismo , Poluentes do Solo/metabolismo , Adsorção , Biodegradação Ambiental , Biomassa , China , Poluentes Ambientais/análise , Concentração de Íons de Hidrogênio , Íons/análise , Cinética , Metais Pesados/análise , RNA Ribossômico 16S , Solo , Águas Residuárias/análise , Poluição da Água/análise
17.
J Environ Sci (China) ; 87: 205-212, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791493

RESUMO

This study aims to investigate the effect of a magnetic field on nitrous oxide (N2O) emission from a sequencing batch reactor treating low-strength domestic wastewater at low temperature (10°C). After running for 124 days in parallel, results indicated that the conversion rate of N2O for a magnetic field-sequencing batch reactor (MF-SBR) decreased by 34.3% compared to that of a conventional SBR (C-SBR). Meanwhile, the removal efficiencies for total nitrogen (TN) and ammonia nitrogen (NH4-N) of the MF-SBR were 22.4% and 39.5% higher than those of the C-SBR. High-throughput sequencing revealed that the abundances of AOB (Nitrosomonas), NOB (Nitrospira) and denitrifiers (Zoogloea), which could reduce N2O to N2, were promoted significantly in the MF-SBR. Enzyme activities (Nir) and gene abundances (nosZ nirS and nirK) for denitrification in the MF-SBR were also notably higher compared to C-SBR. Our study shows that application of a magnetic field is a useful approach for inhibiting the generation of N2O and promoting the nitrogen removal efficiency by affecting the microbial characteristics of sludge in an SBR treating domestic wastewater at low temperature.


Assuntos
Reatores Biológicos , Campos Magnéticos , Óxido Nitroso/análise , Eliminação de Resíduos Líquidos/métodos , Águas Residuárias , Temperatura Baixa , Desnitrificação , Nitrificação , Nitrogênio , Nitrosomonas
18.
J Environ Sci (China) ; 87: 319-330, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791505

RESUMO

Silver nanoparticles (AgNPs) have been widely used in many fields, which raised concerns about potential threats to biological sewage treatment systems. In this study, the phosphorus removal performance, enzymatic activity and microbial population dynamics in constructed wetlands (CWs) were evaluated under a long-term exposure to AgNPs (0, 50, and 200 µg/L) for 450 days. Results have shown that AgNPs inhibited the phosphorus removal efficiency in a short-term exposure, whereas caused no obviously negative effects from a long-term perspective. Moreover, in the coexisting CW system of AgNPs and phosphorus, competition exhibited in the initial exposure phase, however, cooperation between them was observed in later phase. Enzymatic activity of acid-phosphatase at the moderate temperature (10-20°C) was visibly higher than that at the high temperature (20-30°C) and CWs with AgNPs addition had no appreciable differences compared with the control. High-throughput sequencing results indicated that the microbial richness, diversity and composition of CWs were distinctly affected with the extension of exposure time at different AgNPs levels. However, the phosphorus removal performance of CWs did not decline with the decrease of polyphosphate accumulating organisms (PAOs), which also confirmed that adsorption precipitation was the main way of phosphorus removal in CWs. The study suggested that AgNPs and phosphorus could be removed synergistically in the coexistence system. This work has some reference for evaluating the influences of AgNPs on the phosphorus removal and the interrelation between them in CWs.


Assuntos
Nanopartículas Metálicas/toxicidade , Prata/toxicidade , Eliminação de Resíduos Líquidos/métodos , Áreas Alagadas , Biodegradação Ambiental/efeitos dos fármacos , Fósforo/análise , Fósforo/metabolismo , Águas Residuárias , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/toxicidade
19.
Chemosphere ; 238: 124553, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31442776

RESUMO

Although, several recent greenhouse studies are beginning to address the uptake of pharmaceuticals and personal care products (PPCPs) by a variety of crops, few studies have assessed the effects of exposure to complex, realistic wastewater effluents on uptake. Hence, in this study, a greenhouse experiment was conducted in order to study the interactions occurring exclusively between PPCPs in soil, and in the edible plant part of beets (Beta vulgaris) after exposure to treated wastewater effluent. According to the findings, the interactions between the pharmaceuticals caffeine (CFN) with bisoprolol (BSP), carbamezapine (CMZ), clarithromycin (CMC), metoprolol (MPL), sulfamethoxazole (SMX), and trimethoprim (TMP) occurring in soil were almost 99% synergistic; it was noted variability in the interactive capacity of the pharmaceuticals; the concentrations of pharmaceuticals which measured did not affect unfavorably beet yield; interactions between the PPCPs via the PPCPs contribution in plant and soil affect the qualitative and quantitative characteristics of the beets.


Assuntos
Beta vulgaris/crescimento & desenvolvimento , Cosméticos/análise , Preparações Farmacêuticas/análise , Poluentes do Solo/análise , Solo/química , Águas Residuárias/química , Poluentes Químicos da Água/análise , Beta vulgaris/metabolismo , Cosméticos/metabolismo , Preparações Farmacêuticas/metabolismo , Poluentes do Solo/metabolismo , Poluentes Químicos da Água/metabolismo
20.
Chemosphere ; 238: 124559, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31446279

RESUMO

The adsorption of bisphenol-A (BPA) on ordered mesoporous carbon (CMK-3) and modified CMK-3 (MCMK-3) for decontamination of aqueous medium was investigated. The CMK-3 and MCMK-3 materials had uniform pore sizes of 3.60 and 3.70 nm and high Brunauer-Emmett-Teller (BET) surface areas of 751 and 564 m2 g-1, respectively. The maximum adsorption capacities of CMK-3 and MCMK-3 were 178.57 (0.24 mg m-2) and 238.01 (0.42 mg m-2) mg g-1, respectively at 298 K (pH 6.4). The difference in the adsorption capacities is attributed to the specific surface area and hydrophobicity of the adsorbents. The adsorption of BPA on CMK-3 and MCMK-3 may be influenced by π-π bonding and hydrophobic and electrostatic interactions, and the excellent adsorption capacity of MCMK-3 is attributed to its unique sp2-hybridized single-atom-layer structure. The kinetics and isotherm data were described by the pseudo-second order kinetic model and the Langmuir isotherm, respectively. This difference in the adsorption kinetics of CMK-3 and MCMK-3 is caused by the increase in the pore diameter of the latter. Further, CMK-3 and MCMK-3, with an open geometry consisting of interlinked nanorods, allow for faster intraparticle diffusion. Overall, CMK-3 and MCMK-3 could be promising adsorbents for the removal of chemicals containing benzene rings from wastewater.


Assuntos
Compostos Benzidrílicos/isolamento & purificação , Carbono/química , Fenóis/isolamento & purificação , Águas Residuárias/análise , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Adsorção , Compostos Benzidrílicos/metabolismo , Cinética , Fenóis/metabolismo , Águas Residuárias/química , Poluentes Químicos da Água/metabolismo
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