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1.
Bioresour Technol ; 311: 123588, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32475794

RESUMO

The proper treatment of swine wastewater with relatively high concentrations of antibiotics is very important to protect environmental safety and human health. Microbial fuel cell (MFC) technology shows much promise for removing pollutants and producing electricity simultaneously. A double-chamber MFC was investigated in this study. Synthetic swine wastewater with the addition of sulfonamides was used as the fuels in the anode chamber. Results indicated that COD could be effectively removed (>95%) and virtually not affect by the presence of sulfonamides in the MFC. A stable voltage output was also observed. The removal efficiencies of sulfamethoxazole (SMX), sulfadiazine (SDZ), and sulfamethazine (SMZ) in the MFC were in the 99.46-99.53%, 13.39-66.91% and 32.84-67.21% ranges, respectively. These totals were higher than those reported for a traditional anaerobic reactor. Hence, MFC revealed strong resistance to antibiotic toxicity and high potential to treat swine wastewater with antibiotics.


Assuntos
Fontes de Energia Bioelétrica , Águas Residuárias , Animais , Antibacterianos , Eletricidade , Eletrodos , Sulfametoxazol , Suínos
2.
Chemosphere ; 251: 126351, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443222

RESUMO

In recent years, antibiotics have been used for human and animal disease treatment, growth promotion, and prophylaxis, and their consumption is rising worldwide. Antibiotics are often not fully metabolized by the body and are released into the aquatic environment, where they may have negative effects on the non-target species. This review examines the recent researches on eight representative antibiotics (erythromycin, trimethoprim, sulfamethoxazole, tetracycline, oxytetracycline, ofloxacin, ciprofloxacin, and amoxicillin). A detailed overview of their concentrations in surface waters, groundwater, and effluents is provided, supported by recent global human consumption and veterinary use data. Furthermore, we review the ecotoxicity of these antibiotics towards different groups of organisms, and assessment of the environmental risks to aquatic organisms. This review discusses and compares the suitability of currently used ecotoxicological bioassays, and identifies the knowledge gaps and future challenges. The risk data indicate that selected antibiotics may pose a threat to aquatic environments. Cyanobacteria were the most sensitive organisms when using standard ecotoxicological bioassays. Further studies on their chronic effects to aquatic organisms and the toxicity of antibiotic mixtures are necessary to fully understand the hazards these antibiotics present.


Assuntos
Antibacterianos/toxicidade , Monitoramento Ambiental , Poluentes Químicos da Água/toxicidade , Amoxicilina , Animais , Antibacterianos/análise , Organismos Aquáticos , Ciprofloxacino , Ecotoxicologia , Eritromicina , Água Subterrânea , Medição de Risco , Sulfametoxazol , Tetraciclina , Trimetoprima/análise , Poluentes Químicos da Água/análise
3.
Medicine (Baltimore) ; 99(20): e20146, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32443329

RESUMO

BACKGROUND: An increased frequency of toxoplasma encephalitis, caused by Toxoplasma gondii, has been reported in AIDS patients, especially in those with CD4+ T cell counts <100 cells/µL. Several guidelines recommend the combination of pyrimethamine, sulfadiazine, and leucovorin as the preferred regimen for AIDS-associated toxoplasma encephalitis. However, it is not commonly used in China due to limited access to pyrimethamine and sulfadiazine. The synergistic sulfonamides tablet formulation is a combination of trimethoprim (TMP), sulfadiazine and sulfamethoxazole (SMX), and is readily available in China. Considering its constituent components, we hypothesize that this drug may be used as a substitute for sulfadiazine and TMP-SMX. We have therefore designed the present trial, and propose to investigate the efficacy and safety of synergistic sulfonamides combined with clindamycin for the treatment of toxoplasma encephalitis. METHODS/DESIGN: This study will be an open-labeled, multi-center, prospective, randomized, and controlled trial. A total of 200 patients will be randomized into TMP-SMX plus azithromycin group, and synergistic sulfonamides plus clindamycin group at a ratio of 1:1. All participants will be invited to participate in a 48-week follow-up schedule once enrolled. The primary outcomes will be clinical response rate and all-cause mortality at 12 weeks. The secondary outcomes will be clinical response rate and all-cause mortality at 48 weeks, and adverse events at each visit during the follow-up period. DISCUSSION: We hope that the results of this study will be able to provide reliable evidence for the efficacy and safety of synergistic sulfonamides for its use in AIDS patients with toxoplasma encephalitis. TRIAL REGISTRATION: This study was registered as one of 12 clinical trials under the name of a general project at chictr.gov on February 1, 2019, and the registration number of the general project is ChiCTR1900021195. This study is still recruiting now, and the first patient was screened on March 22, 2019.


Assuntos
Síndrome de Imunodeficiência Adquirida/tratamento farmacológico , Infecções por HIV/tratamento farmacológico , Toxoplasmose Cerebral/complicações , Infecções Oportunistas Relacionadas com a AIDS/complicações , Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Infecções Oportunistas Relacionadas com a AIDS/epidemiologia , Síndrome de Imunodeficiência Adquirida/mortalidade , Adolescente , Adulto , Anti-Infecciosos/uso terapêutico , Antiprotozoários/uso terapêutico , China/epidemiologia , Clindamicina/uso terapêutico , Quimioterapia Combinada/métodos , Feminino , Infecções por HIV/mortalidade , Humanos , Leucovorina/uso terapêutico , Masculino , Estudos Prospectivos , Pirimetamina/uso terapêutico , Sulfadiazina/uso terapêutico , Sulfametoxazol/uso terapêutico , Sulfonamidas/uso terapêutico , T-Linfocitopenia Idiopática CD4-Positiva , Toxoplasma/efeitos dos fármacos , Toxoplasma/parasitologia , Toxoplasmose Cerebral/tratamento farmacológico , Toxoplasmose Cerebral/parasitologia , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Complexo Vitamínico B/uso terapêutico
4.
Water Sci Technol ; 81(4): 732-743, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32460276

RESUMO

Wastewater treatment plants are not specially designed to remove pharmaceutically active compounds (PhACs), since these substances are toxic and bio-refractory. This paper aims to investigate and optimize the performance of the Trisep TS80 nanofiltration (NF) membrane for the removal of a mixture of two of the most detected PhACs in municipal wastewaters worldwide, sulfamethoxazole and diclofenac. Several NF tests were carried out to study the rejections of these contaminants both spiked in demineralized water, filtrated water taken from Mondego River and secondary effluent coming from a municipal wastewater treatment plant. Among the several studied operating variables, pH was the one that most affected the contaminant rejection and membrane permeability. In the case of synthetic effluent, an applied pressure of 10 bar and pH 7 were determined as the best operating conditions, which allowed almost total chemical oxygen demand retention and a global contaminant rejection of 96.3% to be achieved. The application of different water matrices (river water and secondary municipal effluent) had no relevant impact on process efficiency. Vibrio fischeri luminescence inhibition tests revealed that treatment by nanofiltration reduced acute toxicity of all studied effluents.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Diclofenaco , Nylons , Rios , Sulfametoxazol , Eliminação de Resíduos Líquidos , Águas Residuárias , Água
5.
Chemosphere ; 253: 126722, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32289608

RESUMO

Levofloxacin (LEV) and sulfamethoxazole (SMX) are two extensively used antibiotics. Most investigations have been concentrated on the toxic effects of antibiotics on algal species evaluated with traditional ecotoxicological endpoints; however, limited information is available on the alterations in biomolecules induced by antibiotics. Here we investigated alterations in the structure and function of biomolecules to a model species Pseudokirchneriella subcapitata following exposure of LEV and SMX by applying Fourier transform infrared spectroscopy (FTIR). The growth inhibition tests revealed that both LEV and SMX had negative effects on algal growth, while SMX was found to be more toxic to P. subcapitata than LEV. Based on the FTIR analysis, alterations in the structure, composition and function of lipids and proteins were observed on microalgal cells, which were correlated with the dosage of LEV and SMX. As a result of lipid peroxidation induced by LEV and SMX, an increase in the lipid/protein ratio and decrease in the ratios of CH2/lipid, CH3/lipid, carbonyl ester/lipid and olefinic = CH/lipid were observed in all treatment groups with respect to the reference control. Moreover, alterations in the composition and secondary structure of proteins were also observed in accompany with a decrease in the Amide I/Amide II ratio and an increase of the loose ß-sheet structure protein. LEV caused an elevated level of lipid peroxidation, while SMX induced a more obvious protein aggregation. The findings from this study showed that FTIR could reveal the toxic mechanism of these two antibiotics to algae at the biochemical level by linking alterations in biomolecules to biochemical dynamics and function.


Assuntos
Antibacterianos/toxicidade , Levofloxacino/toxicidade , Microalgas/efeitos dos fármacos , Sulfametoxazol/toxicidade , Ecotoxicologia , Peroxidação de Lipídeos/efeitos dos fármacos , Lipídeos/química , Estrutura Secundária de Proteína , Proteínas , Espectroscopia de Infravermelho com Transformada de Fourier
6.
Chemosphere ; 253: 126695, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32278902

RESUMO

Antibiotic pollution has become a hot issue worldwide, which has toxic effects on plants and even threatens human health. As a common wetland plant, the tolerance mechanism of Phragmites australis to antibiotics is rarely reported. In this study, we investigated the enrichment characteristics and biological response of P. australis to sulfamethoxazole (SMZ) and ofloxacin (OFL) residues, which are common in the environment. We found that the simulated concentration of antibiotics far exceeded the current level of antibiotic residues in the water environment, but it did not significantly inhibit the growth of P. australis. At 1 mg L-1, OFL and SMZ significantly increased the biomass of P. australis, which was mainly related to the improvement of root activity and photosynthetic efficiency, but the duplex treatment (SMZ + OFL) did not significantly stimulate the growth of reeds. OFL could significantly reduce the accumulation of reactive oxygen species (ROS) in P. australis. When OFL was 1 mg L-1, compared with control, superoxide anion and H2O2 were reduced by 11.19% and 10.76%, respectively, which was mainly related to the improvement of membrane stability. SMZ and SMZ + OFL had no significant effect on ROS, but they significantly increased antioxidant enzyme activity. SMZ and OFL could increase soil invertase, urease, and protease activities, and the tested antibiotics had no significant effect on the Shannon-Wiener index of soil microorganisms. The accumulation of antibiotics within tissues could be ranked as root > leaf > stem, and the accumulation and transport of OFL were higher than those of SMZ.


Assuntos
Ofloxacino/toxicidade , Poaceae/fisiologia , Sulfametoxazol/toxicidade , Antibacterianos , Biomassa , Tolerância a Medicamentos , Peróxido de Hidrogênio , Fotossíntese , Folhas de Planta , Poaceae/efeitos dos fármacos , Poaceae/crescimento & desenvolvimento , Solo/química , Áreas Alagadas
7.
Water Res ; 177: 115809, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32311579

RESUMO

Eliminating pharmaceutical active compounds from source-separated urine is essential for nutrient recovery and reducing the contaminant load to wastewater treatment plants. However, limited oxidation treatment processes have shown satisfactory performance due to strong scavenging effect of urine components. This study proposed a heterogeneous catalytic system by combining biochar with peroxydisulfate (PDS), which effectively removed sulfamethoxazole (SMX) and its major human metabolite, N4-acetyl-sulfamethoxazole (NSMX) in urine. The performance of biochar/PDS was investigated in both a complete-mixing reactor and a biochar-packed column. Interestingly, urine components slightly inhibited the degradation of sulfonamides in biochar suspension but significantly improved their removal in biochar-packed column. Further investigation elucidated the PDS activation process and the effects of the main urine components, which explained the different results in biochar suspension and biochar-packed column. The biochar/PDS system mainly produced ·OH radical, singlet oxygen and surface-bound radicals (SBR), which transformed SMX to products of no apprarent antimicrobial properities. A cost-effective two-stage process was designed utilizing SBR as the major reactive species. This study may help to improve the understanding of the catalytic role of biochar and provide cost-effective treatment options for urine.


Assuntos
Carvão Vegetal , Poluentes Químicos da Água , Catálise , Humanos , Sulfametoxazol , Águas Residuárias
8.
Chemosphere ; 250: 126133, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32234615

RESUMO

The metal-organic frameworks MOF-525 and MOF-545 comprised of Zr-oxide clusters and porphyrin moieties in different geometries were synthesized solvothermally and applied for the adsorptive removal of the broadly used organic contaminant sulfamethoxazole (SMX) from water. Both MOFs were found highly efficient for the adsorption of SMX with the maximum adsorption capacities of 585 and 690 mg/g for MOF-525 and MOF-545, respectively. The latter value is the highest adsorption capacity reported so far for the adsorption of SMX molecules on any adsorbent. The adsorption equilibrium could be modeled successfully by the Langmuir model, which showed close to matching with the experimental data. Their adsorption equilibriums were attained within 120 and 30 min for MOF-525 and MOF-545, respectively. MOF-545 with mesopores demonstrated superior adsorption kinetics to MOF-525 with micropores, and the simulation by the pseudo-second-order kinetic model indicated ca. 20 times faster adsorption by MOF-545 than MOF-525. Both showed pH-dependent adsorption of SMX with a gradual reduction at high pH due to the repulsion between negatively charged adsorbent and SMX. The adsorption of SMX conducted over a group of representative MOFs with different physicochemical properties and detailed characterization confirmed that the high adsorption capacity of the porphyrin MOFs is achieved by H-bonding between the SMX molecule and the N-sites of the porphyrin units in the MOFs, π-π interaction, and the high surface area. The adsorbents were easily regenerated by simple washing with acetone and reusable with >95% efficiency during 4 repeated adsorption-desorption cycles.


Assuntos
Sulfametoxazol/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Cinética , Estruturas Metalorgânicas , Óxidos , Água , Poluentes Químicos da Água/análise
9.
Water Res ; 175: 115656, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32145399

RESUMO

Microalgae-mediated biodegradation of antibiotics has recently gained increased attention from international scientific community. However, limited information is available regarding microalgae-mediated biodegradation of SMX in a co-metabolic system. Here we investigated the biodegradation of sulfamethoxazole (SMX) by five algal species (Pseudokirchneriella subcapitata, Scenedesmus quadricauda, Scenedesmus obliquus, Scenedesmus acuminatus and Chlorella pyrenoidosa), and its transformation pathways by C. pyrenoidosa in a sodium acetate (3 mM) co-metabolic system. The results showed that the highest SMX dissipation (14.9%) was detected by C. pyrenoidosa after 11 days of cultivation among the five tested algal species in the absence of other carbon sources. The addition of sodium acetate (0-8 mM) significantly enhanced the dissipation efficiency of SMX (0.4 µM) from 6.05% to 99.3% by C. pyrenoidosa after 5 days of cultivation, and the dissipation of SMX followed the first-order kinetic model with apparent rate constants (k) ranging from 0.0107 to 0.9811 d-1. Based on the results of mass balance analysis, biodegradation by C. pyrenoidosa was the main mechanism for the dissipation of SMX in the culture medium. Fifteen phase I and phase II metabolites were identified, and subsequently the transformation pathway was proposed, including oxidation, hydroxylation, formylation and side chain breakdown, as well as pterin-related conjugation. The majority of metabolites of SMX were only observed in the culture medium and varied with cultivation time. The findings of the present study showed effective co-metabolism of a sulfonamide by microalgae, and it may be applied in the aquatic environment remediation and wastewater treatment in the future.


Assuntos
Chlorella , Microalgas , Scenedesmus , Água Doce , Sulfametoxazol
10.
Chemosphere ; 251: 126403, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32171942

RESUMO

Emerging contaminants, especially, pharmaceutical and personal care products (PPCPs) are not removed well during conventional wastewater treatment and hence pose water quality risk to the environment and potentially to public health. Long-term use of reclaimed wastewater for irrigation can lead to accumulation of trace contaminants in the soil, ground water and their subsequent uptake by plants and potentially can enter human food chain. This paper uses biochar as an adsorbent to remove emerging contaminants from treated wastewater by performing fixed bed experiments. Ten emerging contaminants namely, carbamazepine (CBZ), caffeine, diethyltoluamide (DEET), diphenhydramine (DPH), meprobamate (MPB), primidone (PMD), sulfamethoxazole (SMX), fluoxetine (FXT), perfluorooctanoic acid (PFOA) and trimethoprim (TMP) were monitored during lab scale experiments. Results from the continuous flow runs showed that the breakthrough curve for compounds caffeine, CBZ, DEET and PFOA follow second order Thomas model with adsorption capacities of 396 µg g-1, 392 µg g-1, 1160 µg g-1 and 32 µg g-1 biochar, respectively. Whereas compounds such as DPH, TMP and FXT were completely removed throughout the column runs by biochar. Results for rest of the compounds were interfered by leaching of these compounds from biochar. It was observed that commercially available GAC performed much better than biochar for all the compounds considered. Even at 1% of obtained capacity, biochar amendment to soils where reclaimed water is used for irrigation can reduce the uptake of these compounds by plants.


Assuntos
Irrigação Agrícola/métodos , Carvão Vegetal/química , Eliminação de Resíduos Líquidos/métodos , Adsorção , Carbamazepina , Cosméticos/análise , Água Subterrânea , Humanos , Solo/química , Poluentes do Solo/análise , Sulfametoxazol , Águas Residuárias/química , Água , Poluentes Químicos da Água/análise
11.
Sci Total Environ ; 712: 135759, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-32050397

RESUMO

Considering the inevitable release of antibiotics and nanoparticles (NPs) into the nitrogen containing wastewater, the combined impact of CuO NPs and sulfamethoxazole (SMX) antibiotic on partial nitrification (PN) process was investigated in four identical reactors. Results showed that the bioactivity of the aerobic ammonia-oxidizing bacteria (AOB) decreased by half after they were exposed to the combination of CuO NPs and SMX for short-term; however, there was no obvious variation in the bioactivity of AOB when they were exposed to either CuO NPs or SMX. During long-term exposure, the ammonia removal efficiency (ARE) of CuO NPs improved whereas that of SMX decreased, while the combination of CuO NPs and SMX significantly decreased ARE from 62.9% (in control) to 38.2% and had an unsatisfactory self-recovery performance. The combination of CuO NPs and SMX significantly changed the composition of microbial community, decreased the abundance of AOB, and significantly suppressed PN process. Reegarding the resistance genes, the CuO NPs-SMX combination did not improve the expression of copA, cusA, sul1 and sul2; however, it significantly induced the expression of sul3 and sulA.


Assuntos
Esgotos , Antibacterianos , Cobre , Nanopartículas Metálicas , Nitrificação , Sulfametoxazol
12.
Chemosphere ; 248: 125911, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32007769

RESUMO

This paper presents an evaluation of UV/PAA process for degradation of four pharmaceuticals venlafaxine (VEN), sulfamethoxazole (SFX), fluoxetine (FLU) and carbamazepine (CBZ) with comparison to UV/H2O2 process. The effectiveness of combining PAA and H2O2 at various proportions while irradiating with UVC were also evaluated. UVC/PAA (λ = 254 nm) was effective in degrading all four pharmaceuticals and followed pseudo first-order kinetics. Increasing PAA dosage or UVC intensity resulted in a linear increase in pseudo-first order rate coefficient. Both PAA in dark conditions and UVA/PAA (λ = 360 nm) were marginally effective to degrade SFX and ineffective to degrade VEN, CBZ and FLU; indicating the need for UVC irradiation for activation of PAA. For similar oxidant dosages of 50 mg/L UVC/H2O2 was found to be faster than UV/PAA for VEN, CBZ and FLU by 55%, 75% and 33%, respectively. Under similar conditions, SFX was degraded 24% faster by UV/PAA. Increase in the proportion of H2O2 to PAA in UVC/PAA/H2O2 improved kinetics of degradation compared to PAA alone. Tests on TOC were conducted to determine the amount of acetic acid that is released to water when treatment by UVC/PAA is conducted. Results demonstrated that 70% of PAA by mass was ultimately converted to acetic acid and remained in the treated solutions. Hydroxyl radical attack is hypothesized to be the main mechanism of degradation by UV/PAA as degradation intermediates identified for all the target pharmaceuticals coincided with by-products identified during UV/H2O2 process.


Assuntos
Preparações Farmacêuticas/química , Poluentes Químicos da Água/química , Carbamazepina , Peróxido de Hidrogênio , Radical Hidroxila , Cinética , Modelos Químicos , Oxirredução , Ácido Peracético , Sulfametoxazol , Raios Ultravioleta , Cloridrato de Venlafaxina , Águas Residuárias , Água , Purificação da Água
13.
Chemosphere ; 248: 126085, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32041071

RESUMO

Hormesis is an ecotoxicological phenomenon referred to as the biphasic dose-response effect. At a low concentration of toxic substances, a hormetic stimulating effect occurs, while an inhibitory effect occurs at higher concentrations. The phenomenon of hormesis may hinder the interpretation of toxicity test results and lower the actual toxicity of test samples. In this study, a hormesis phenomenon was observed and analysed during toxicity tests of wastewater from constructed wetlands containing two pharmaceutical substances, diclofenac (DCF) and sulfamethoxazole (SMX), against the marine bacteria Aliivibrio fischeri. To eliminate the hormesis phenomenon, a change in the diluent (ISO 11348-3:2007) to synthetic sea water (ISO 10253:2006) is proposed. The hormesis phenomenon was observed only during the analysis of wastewater toxicity with the standard toxicity test (with the diluent). The use of synthetic sea water eliminated the hormetic effects because of the presence of additional components in the sea water, such as MgCl2, Na2SO4, CaCl2, KCl, NaHCO3, and H3BO3, which increased the sensitivity of A. fischeri to the pharmaceutical substances. The use of different media in toxicity tests may have significant effects on the toxicity classification of the tested compounds or wastewater. Additionally, the toxicity of tested pharmaceuticals towards A. fischeri was analysed. The IC50 values of DCF were 8.7 ± 1.1 mg L-1 (for diluent) and 13.9 ± 0.9 mg L-1 (for synthetic sea water) whereas those of SMX were 50.5 ± 2.3 and 55.3 ± 1.6 mg L-1, respectively.


Assuntos
Aliivibrio fischeri/efeitos dos fármacos , Hormese/efeitos dos fármacos , Água do Mar/química , Testes de Toxicidade/métodos , Diclofenaco/toxicidade , Ecotoxicologia , Sulfametoxazol/toxicidade , Águas Residuárias/química , Poluentes Químicos da Água/toxicidade
14.
Chemosphere ; 250: 126252, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32097812

RESUMO

This study evaluated the removal efficiencies of sulfamethoxazole (SMX), tetracycline (TC) and their common co-existing contaminants, i.e., chemical oxygen demand (COD) and nitrogen in constructed wetlands integrated with microbial fuel cells (MFC-CWs), as affected by plant, circuit operation mode and influent antibiotic loads. The results demonstrated that MFC-CWs with plant and circuit connection exhibited the best performance in SMX and TC removal. The removal percentages for SMX and TC were 99.70-100% and 99.66-99.85% at HRT of 1 d, respectively, in MFC-CWs with plant and circuit connection when the influent SMX and TC concentrations were 5-100 µg L-1 and 5-50 µg L-1. The removal efficiencies of both SMX and TC were mainly enhanced by the circuit connection, compared to the plants. The presence of plant and circuit connection also accelerated the accumulation of SMX and TC in electrode layers, and the residues of both antibiotics in the anode layer were higher than in the cathode layer. Besides, closed-circuit MFC-CWs showed better COD removal performance than open-circuit MFC-CWs, irrespective of the increasing influent COD and antibiotic concentrations. The NH4+-N removal in MFC-CWs was mainly promoted by the presence of plants and decreased with increasing influent antibiotic concentrations. Additionally, the bioelectricity generation of planted MFC-CWs was better than in unplanted systems. The coulombic efficiencies in both planted and unplanted MFC-CWs decreased with increasing influent antibiotic concentrations. In summary, MFC-CWs with plant and circuit connection have potential for the treatment of wastewater containing SMX and TC.


Assuntos
Antibacterianos/metabolismo , Fontes de Energia Bioelétrica , Eliminação de Resíduos Líquidos/métodos , Áreas Alagadas , Antibacterianos/análise , Análise da Demanda Biológica de Oxigênio , Eletrodos , Nitrogênio , Plantas , Sulfametoxazol , Tetraciclina , Águas Residuárias/química
15.
Sci Total Environ ; 718: 137299, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32088478

RESUMO

A novel adsorbent of sludge biochar (SBC) and multi-walled carbon nanotube (CNT) composite was synthesized (CNT-SBC) to remove low concentrations of sulfamethoxazole (SMX) from water. The key factors of dose, contact time, pH and temperature were investigated. Higher dose of adsorbents provided more active sites for SMX adsorption. The effect of pH was due to the electrostatic interaction. Increasing the temperature was beneficial to SMX adsorption, which was a spontaneous endothermic process and the strength of the spontaneous increased with CNT supporting. As pseudo-second-order, Elovich, Langmuir and Freundlich models fitted the experimental data better, this suggested that both physisorption and chemisorption played vital roles during the adsorption process. In addition, liquid film diffusion was the main rate-limiting step of adsorption. Compared with SBC (5.43 × 103 µg g-1), CNT-SBC-1 (CNT:SBC = 1:2), CNT-SBC-2 (CNT:SBC = 1:4) and CNT-SBC-3 (CNT:SBC = 1:6) exhibited better adsorption performance with up to 2.35 × 104, 1.49 × 104 and 1.22 × 104 µg g-1 at 25 °C, respectively. The characterization analysis demonstrated that the stronger adsorption capacity of CNT-SBC was mainly attributed to the pore filling, functional groups complexation and π-π interaction. In summary, as an efficient and environment-friendly adsorbent, CNT-SBC has promising potential for low concentrations of SMX and other emerging contaminants removal from water.


Assuntos
Nanotubos de Carbono , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Cinética , Esgotos , Sulfametoxazol
16.
Environ Pollut ; 259: 113795, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31918128

RESUMO

Hydroxyl radical (•OH)- and sulfate radical ()-based advanced oxidation technologies (AOTs) have been proven an effective method to remove antibiotics in wastewater treatment plants (WWTPs). This study aims to gain insights into kinetics and mechanisms of neutral sulfamethoxazole (SMX) degradation, a representative antibiotic, by •OH and using an experimental and theoretical approach. First, the second-order rate constants (k) of SMX with •OH and were determined to be (7.27 ± 0.43) × 109 and (2.98 ± 0.32) × 109 M-1 s-1 in UV/H2O2 and UV/persulfate (UV/PS) systems, respectively. The following theoretical calculations at the M06-2X level of theory revealed that addition of radicals to the benzene ring is the most favorable first-step reaction for both •OH and , but that exhibits higher energy barriers and selectivity than •OH due to steric hindrance. We further analyzed subsequent reactions and, interestingly, our findings closely corroborated HOMO/LUMO distributions of SMX to the oxidation pathways. Finally, the estimation of energy consumption for UV alone, •OH-, and -mediated oxidation processes was compared. These comparative results, for the first time, provide insights into the similarities and differences of degradation of SMX by •OH/ at the molecular level and can help improve antibiotics removal using radical based AOTs in WWTPs.


Assuntos
Radical Hidroxila/farmacocinética , Sulfametoxazol/química , Sulfatos/farmacocinética , Poluentes Químicos da Água/química , Peróxido de Hidrogênio/química , Cinética , Oxirredução , Raios Ultravioleta
17.
Chemosphere ; 246: 125783, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31918096

RESUMO

Developing an efficient and metal-free bifunctional catalyst for the simultaneous degradation of antibiotic and reduction of Cr (VI) has been regarded as increasingly attractive yet challenging objectives in the environmental catalysis field. Herein, phosphorus-doped carbon fibers (P-CFs) was innovatively prepared by doping and calcination methods, characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Sulfamethoxazole (SMX) as the target contaminant was selected to evaluate the catalytic activity of P-CFs in PMS activation, over 90% SMX removal and 82.75% mineralization were high-efficiently achieved in the P-CFs/peroxymonosulfate (PMS) system. Particularly, P-CFs/PMS system exhibited a superior catalytic oxidation performance over a wide pH range (3.5-9.5) and even in the complicated water matrix. Surprisingly, the presence of humic acid (HA) in the P-CFs/PMS system could achieve about 2 times enhancement on SMX removal, different from most reports about the inhibition of HA in PMS activation. More importantly, Brunauer-Emmett-Teller (BET) method and XPS analysis revealed that the highly toxic Cr (VI) could be reduced to Cr (III) by P-CFs. Furthermore, electron spin resonance (ESR) combined with various trapping agents demonstrated that SO4•-, •OH and 1O2. were generated and participated in the SMX degradation, while the free electron in P-CFs played a main role in Cr (VI) reduction. This finding not only provided a high-efficiency strategy in the treatment of wastewaters containing organic contaminants and heavy metals Cr (VI), but might open new insights into an innovative metal-free catalyst in environment remediation.


Assuntos
Fibra de Carbono/química , Cromo/química , Fósforo/química , Sulfametoxazol/química , Poluentes Químicos da Água/química , Catálise , Metais , Oxirredução , Peróxidos , Espectroscopia Fotoeletrônica , Água , Purificação da Água/métodos
18.
Chemosphere ; 247: 125837, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31927185

RESUMO

Application of low dosage of H2O2 at early stage of cyanobacterial life cycle is a promising route for cyanobacterial bloom mitigation, which could minimize adverse effects on non-target organisms. Besides, influence of co-existing contaminants on cyanobacterial bloom mitigation under combined pollution conditions remains unclear. This study assessed the influence of a mixture of four frequently detected antibiotics (tetracycline, sulfamethoxazole, ciprofloxacin and amoxicillin) during H2O2 treatment of Microcystis aeruginosa at early growth stage. H2O2 significantly (p < 0.05) inhibited growth rate, chlorophyll a content, Fv/Fm and rETRmax in a dose-dependent manner at low doses of 0.25-1 mg L-1, through downregulating proteins involved in cell division, cellular component organization, gene expression and photosynthesis. Although H2O2 increased microcystin content in each cyanobacterial cell through the upregulation of microcystin synthetases (mcyC and mcyF), total microcystin concentration in H2O2 treated groups was significantly (p < 0.05) reduced due to the decrease of cell density. Existence of 80 and 200 ng L-1 mixed antibiotics during H2O2 treatment facilitated the scavenging of ROS by antioxidant enzymes and significantly (p < 0.05) stimulated growth, photosynthesis, microcystin synthesis and microcystin release in H2O2 treated cells, through the upregulation of proteins involved in photosynthesis, oxidation-reduction process, biosynthesis, gene expression and transport. Mixed antibiotics increased the hazard of M. aeruginosa during H2O2 treatment, through the stimulation of microcystin synthesis and release at the proteomic level. Each target antibiotic should be controlled below 5 ng L-1 before the application of H2O2 for eliminating the interference of antibiotics on cyanobacterial bloom mitigation.


Assuntos
Antibacterianos/farmacologia , Peróxido de Hidrogênio/farmacologia , Microcystis/efeitos dos fármacos , Proteômica/métodos , Amoxicilina/farmacologia , Clorofila A , Ciprofloxacino/metabolismo , Cianobactérias/efeitos dos fármacos , Microcistinas/biossíntese , Microcystis/metabolismo , Oxirredução , Fotossíntese/efeitos dos fármacos , Sulfametoxazol/metabolismo
19.
Chemosphere ; 246: 125642, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31901530

RESUMO

The widespread occurrence of synthetic antibiotic sulfamethoxazole (SMX)- poses a potential risk to aquatic ecosystems where dissolved organic matter (DOM) may affect its photolysis. In this study, the elimination of SMX by solar photolysis was investigated in the presence of leonardite humic acid (LHA) and its fractions. Fourier transform ion cyclotron resonance mass (FT-ICR-MS) spectra showed that LHA has high aromaticity. van Krevelen diagrams demonstrated highly unsaturated and phenolic compounds. The photolytic degradation of SMX was impeded by all DOM, mainly due to the competition of photons and scavenging or quenching of reactive oxygen species (ROS). The evaluation of isolated fractions of LHA suggested that fractions with MW < 3500, 14000-25,000 and > 100,000 had the greatest negative effects on sulfamethoxazole photodegradation; their inhibitory activities could reach up to 56.2%, 52.9% and 50.5%, respectively. The characterization of DOM at the molecular level will provide further insights into the assessment of photolysis for antibiotic elimination in natural waters where DOM exists ubiquitously.


Assuntos
Minerais/química , Sulfametoxazol/química , Antibacterianos , Fracionamento Químico , Ecossistema , Substâncias Húmicas/análise , Espectrometria de Massas , Modelos Químicos , Fenóis , Processos Fotoquímicos , Fotólise , Luz Solar
20.
Bioresour Technol ; 297: 122463, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31786036

RESUMO

The effects of sulfamethoxazole and norfloxacin on nitrogen functional genes were investigated in four composting treatments of swine manure: CK (no antibiotics), SMZ (spiked with 5 mg kg-1 dry weight (DW) sulfamethoxazole), NOR (spiked with 5 mg kg-1DW norfloxacin), and SN (spiked with 5 mg kg-1DW sulfamethoxazole and 5 mg kg-1DW norfloxacin). Antibiotics decreased relative abundance of bacterial amoA and nxrA, while increased nosZ/nirK. The decline in amoA/16S rRNA increased the total NH3 emission in SMZ and NOR from 1027.05 to 1144.39 and 1278.22 mg kg-1DW. The decrease of nxrA/16S rRNA enhanced the NO2--N content and N2O emission in SMZ in the initial composting. Additionally, the increase in nosZ/nirK probably was the main reason for the lower N2O emission in SN than other treatments in the cooling phase. The inhibition on nitrification process and increase in NH3 emission resulted from antibiotics is worthy of attention in the future.


Assuntos
Compostagem , Animais , Desnitrificação , Esterco , Nitrogênio , Norfloxacino , RNA Ribossômico 16S , Solo , Sulfametoxazol , Suínos
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