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1.
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
2.
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
3.
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
4.
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
5.
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
6.
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
7.
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
8.
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
9.
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
10.
Chemosphere ; 241: 125002, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31590027

RESUMO

Iron and copper bimetallic MOF material (FexCu1-x(BDC)) as a novel Fenton-like catalyst was prepared by a simple solvothermal method, and its performances were evaluated in the catalytic degradation of sulfamethoxazole (SMX) in the presence of hydrogen peroxide. The results indicated that the FexCu1-x(BDC)/H2O2 system was highly effective for SMX degradation over a wide pH range (4.0-8.6). At initial solution pH of 5.6, the bimetallic Fe0.75Cu0.25(BDC) catalyst exhibited a 100% SMX (20 mg L-1) removal within 120 min, which was superior to the SMX removal efficiency over monometallic Fe(BDC) and Cu(BDC) catalysts. Combined with the physical-chemical characterization, the synergistic effect between Fe and Cu species were responsible for the efficient catalytic activity. Moreover, the Fe0.75Cu0.25(BDC) catalyst showed good reusability for SMX degradation. The possible reaction mechanism in FexCu1-x(BDC)/H2O2 system was also tentatively proposed. This work has not only suggested the potential of bimetallic FexCu1-x(BDC) catalysts in Fenton-like treatment of antibiotics, but also provided useful information to develop MOF-based catalysts for efficient environmental remediation.


Assuntos
Cobre/química , Recuperação e Remediação Ambiental/métodos , Ferro/química , Estruturas Metalorgânicas/química , Sulfametoxazol/química , Catálise , Peróxido de Hidrogênio/química , Estruturas Metalorgânicas/farmacologia , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
11.
Environ Technol ; 41(7): 870-877, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30139300

RESUMO

Sulfamethoxazole (SMX) is a commonly used antibiotic for both human and animals. The frequent detection of SMX in natural water bodies and sediment has become an issue of great environmental concern due to its potential risk to induce antibiotic resistance in pathogenic bacteria. In the present work, the catalytic wet peroxide oxidation (CWPO) was investigated to remove SMX with sludge-derived carbon (SC) as a cheap alternative catalyst. Different acids were used to modify SC. It was found that SC modified with sulphuric acid (SC-H2SO4) demonstrated the best catalytic activity. The removal efficiency of SMX and TOC was 97.7% and 65.7%, respectively, after 260 min, at pH 5 with a dosage of 220 mg/L H2O2. The effects of temperature, initial pH and H2O2 dosage were also investigated. The study demonstrated that the increase of temperature could significantly improve the degradation of SMX from 10.0% at 20°C to 94.7% at 60°C.


Assuntos
Sulfametoxazol , Poluentes Químicos da Água , Carbono , Peróxido de Hidrogênio , Oxirredução , Peróxidos , Esgotos
12.
Einstein (Sao Paulo) ; 18: eRC5002, 2020.
Artigo em Inglês, Português | MEDLINE | ID: mdl-31778467

RESUMO

The fixed drug eruption is a non-immediate hypersensitivity reaction to drug, characterized by recurrent erythematous or violaceous, rounded, well-defined border plaques, which always appear in the same location every time the culprit drug is administered. The usual practice is to avoid the drug involved and to use a structurally different drug. However, there are situations in which there is no safe and effective therapy. In such situations, desensitization is the only option. We describe the case of a patient who presented fixed eruption due to sulfamethoxazole-trimethoprim, who underwent successful desensitization, but required a repeat procedure twice due to relapse after inadvertent full-dose reintroduction. In non-immediate hypersensitivity reaction to drug, the indication is controversial and there is no technical standardization. Furthermore, the time at which such tolerance is lost after discontinuing the drug involved is unknown. In severe non-immediate reactions of types II and III, desensitization is contraindicated. The patient underwent desensitisation to sulfamethoxazole-trimethoprim three times - the first with recurrence of lesions and the second and third without manifestations, all concluded successfully and with no premedication.


Assuntos
Dessensibilização Imunológica/métodos , Erupção por Droga/tratamento farmacológico , Erupção por Droga/etiologia , Combinação Trimetoprima e Sulfametoxazol/efeitos adversos , Idoso , Hipersensibilidade a Drogas/tratamento farmacológico , Hipersensibilidade a Drogas/etiologia , Humanos , Masculino , Sulfametoxazol/efeitos adversos , Trimetoprima/efeitos adversos
13.
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
14.
Sci Total Environ ; 703: 135562, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31767303

RESUMO

Plant-soil systems have complex regulatory mechanisms for xenobiotics uptake by plant, and these chemicals in soil pore water (SPW) are regarded as the bioavailable fraction. To date, little is known about the role of SPW in regard to the bioavailability of antibiotics for plant. In this study, in situ soil moisture sampler (SMS) was adopted to collect SPW from four paddy soils without disrupting the rhizosphere zone to evaluate antibiotic uptake in rice. The results show that SMS is applicable for antibiotics that have small molecular sizes and Log Kow values, e.g., sulfadiazine (SDZ), sulfamethoxazole (SMZ), trimethoprim (TRM), and florfenicol (FLR). However, SMS performance was not feasible for large size and medium hydrophobic clarithromycin (CLR). Antibiotics in SPW demonstrated differences among chemicals and soils. Relatively higher levels of SDZ, SMZ, and FLR were observed in SPW than TRM, and neutral Panjin soil had the highest levels of antibiotics in SPW among four soils. The levels of antibiotics in SPW were negatively correlated with their soil partition parameter, Kd. Rapid decreases of SMZ, FLR, and SDZ in the SPW were consistent with their low residues in the final soils. All antibiotics were detectable in rice roots, followed by low detection levels in a few shoot samples, while no antibiotics were detectable in the grains of four soils. Relatively higher levels of SDZ, SMZ and FLR were observed in the roots of Panjin soil, consistent with their levels in SPW and Kd values. Furthermore, CLR and TRM were observed to have higher levels in roots, which was regarded as a consequence of their relatively longer persistence. Our study indicates that SMS is an applicable technique for in situ sampling of SPW, and level of antibiotics in SPW can work as a useful indicator to explore their bioavailability to plants.


Assuntos
Antibacterianos/análise , Monitoramento Ambiental , Poluentes do Solo/análise , Rizosfera , Solo/química , Sulfametoxazol , Trimetoprima , Água
15.
Sci Total Environ ; 703: 135586, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31767336

RESUMO

The pharmaceutical industry produces large volumes of low C/N ratio wastewater that is difficult to treat. In this study, we isolated Achromobacter sp. JL9 with high efficiency for sulfamethoxazole degradation and nitrogen conversion in low C/N ratio pharmaceutical wastewater. The SMX biodegradation and nitrogen removal ratio were 92.4% (nitrate-N), 86.7% (ammonia-N), 89.4% (total nitrogen), and 90.4% (SMX). The reaction kinetics and reaction rate constant were C/N ratio-, SMX concentration-, and dissolved oxygen concentration-dependent, and the highest reaction rate constant for SMX biodegradation was 0.0384 min-1. Gaseous compounds analysis and Nap gene amplification analysis by gas chromatography (GC) and polymerase chain reaction (PCR), respectively, showed N2 as an end product during nitrogen conversion. Moreover, toxicity assays were conducted by the inhibition percentage (PI) and agar well diffusion methods. The toxicity of the medium gradually decreased, falling within the nontoxic range after 96 h. The present study showed that biological technologies could be an effective, economical, and environmentally friendly remediation against pharmaceutical pollutants.


Assuntos
Achromobacter/metabolismo , Biodegradação Ambiental , Nitrogênio/metabolismo , Sulfametoxazol/metabolismo , Poluentes Químicos da Água/metabolismo , Águas Residuárias/química , Águas Residuárias/microbiologia
16.
Chemosphere ; 245: 125644, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31864051

RESUMO

The ACF-cathode/Co2+/PDS system was validated to effectively remove sulfamethoxazole (SMX), a typical carcinogenic and refractory antibiotic from the aqueous environment. The experimental conditions such as initial pH, PDS, Co2+ concentrations, and current density were optimized. Moreover, the system exhibited excellent ability for SMX degradation in surface water and tap water. It was proved that ACF-cathode/Co2+/PDS consumes much less electrical energy per order (EEO) values than Pt-cathode/Co2+/PDS processes. More importantly, due to the cathodic protection, the removal rate of SMX within 30 min was satisfactory even after ACF used for 10 cycles continuously. In addition, the cobalt residue in the ACF-cathode/Co2+/PDS process was much lower than that of Pt-cathode/Co2+/PDS system due to the deposition of cobalt on ACF surface. The catalytic system not only had high catalytic performance, but also had less cobalt residue in the solution and lower power consumption. Therefore, the study provided a novel technology for the removal of refractory pollutants in water.


Assuntos
Sulfametoxazol/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Fibra de Carbono/química , Carvão Vegetal/química , Cobalto/química , Fibras na Dieta , Eletrodos , Oxirredução , Água , Poluentes Químicos da Água/análise
17.
Chemosphere ; 245: 125555, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31864949

RESUMO

During the process of persulfate oxidation, side reactions such as the recombination of radicals can usually result in the low utilization efficiency of persulfate, which decreases the mineralization of target pollutants. In this study, the successive oxidation strategy was proposed based on successive non-radical and radical process (SNRP), to enhance the utilization efficiency of peroxymonosulfate (PMS), and further enhance the mineralization of sulfonamides. The results indicated that 0.04 mM of sulfonamide could be completely removed within 240 min at 1.2 mM PMS and initial pH 6.8 in the non-radical process, but the mineralization was very low (<2%). Moreover, the decomposition efficiency of PMS was less than 10% within 480 min. Fe(II) was added into the solution in which non-radicals process was performed, to initiate radical process by activating residual PMS. Compared to Fe(II)/PMS process, the SNRP process significantly increased the mineralization of sulfonamides, reaching 27.0%, 19.0%, 16.7% and 17.2%, respectively for sulfamethoxazole, sulfanilamide, sulfadiazine and sulfamerazine. The increased mineralization was due to the enhanced PMS utilization. Seven degradation products were identified in the SNRP process. Among them, hydrolyzed 3-amino-5-methyl isoxazole, (3-amino-5-methylisoxazole) sulfonic acid and 4-aminobenzenesulfinic acid produced in the non-radical oxidation process showed resistance to the subsequent radical oxidation. This study can provide a possible way to enhance the utilization efficiency of PMS as well as the mineralization of organic pollutants.


Assuntos
Modelos Químicos , Sulfatos/química , Poluentes Ambientais/química , Oxirredução , Peróxidos , Sulfadiazina , Sulfametoxazol , Sulfonamidas
18.
Chemosphere ; 239: 124730, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31726518

RESUMO

The impact of electrolytes on the adsorption of emerging pollutants: pharmaceuticals onto layered materials: a raw clay mineral and its nonionic and cationic organoclay derivatives was studied. The selected pharmaceuticals: amoxicillin, norfloxacin, sulfamethoxazole, metoprolol, carbamazepine, and trimethoprim show different electric charges: zwitterionic, anionic, cationic and neutral and hydrophobic character (different LogP). Without any salts, the set of complementary data obtained by UV and infrared spectroscopies, X-ray diffraction points out the importance of the electric charge which represents a key parameter in both the spontaneity and feasibility of the adsorption. In contrast, the hydrophobicity of the analytes plays a minor role but determines the magnitude of the adsorbed amount of pharmaceuticals onto organoclays. With a dual hydrophilic and hydrophobic behavior, nonionic organoclay appears to be the most polyvalent material for the removal of the pharmaceuticals. In the presence of electrolytes (NaCl at a concentration of 1 × 10-2 mol L-1), both nonionic and cationic organoclays show a decrease of their efficiencies, whereas the adsorption is particularly enhanced for Na-Mt except for the cationic species (trimethoprim and metoprolol). Thus, in realistic experimental conditions close to those of natural effluents, raw clay mineral appears as the most appropriate sorbent for the studied pharmaceuticals while it raises the question of the usefulness of organoclays in water remediation strategy.


Assuntos
Eletrólitos/química , Recuperação e Remediação Ambiental/métodos , Preparações Farmacêuticas/análise , Poluentes do Solo/análise , Solo/química , Poluentes Químicos da Água/análise , Adsorção , Amoxicilina/análise , Amoxicilina/química , Carbamazepina/análise , Carbamazepina/química , Cátions/análise , Interações Hidrofóbicas e Hidrofílicas , Metoprolol/análise , Metoprolol/química , Norfloxacino/análise , Norfloxacino/química , Preparações Farmacêuticas/química , Poluentes do Solo/química , Sulfametoxazol/análise , Sulfametoxazol/química , Trimetoprima/análise , Trimetoprima/química , Água/química , Poluentes Químicos da Água/química , Difração de Raios X
19.
Ecotoxicol Environ Saf ; 190: 110022, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31865205

RESUMO

Reclaimed wastewater (RW) is increasingly used to irrigate agricultural land and to alleviate agricultural water shortages worldwide. This usage has resulted in concerns about soil contamination by pharmaceuticals and personal care products (PPCPs) and the human health risks associated with dietary crop intake. In this study, we systematically analysed the occurrence and accumulation of 11 PPCPs and one active metabolite in soils and various crops (cucumber, eggplant, long bean and wheat) from realistic RW irrigation fields with different irrigation histories (20, 30 and 40 years) in Beijing and evaluated the human health risks associated with the consumption of these crops. The 11 PPCPs and one active metabolite were detected at concentrations ranging from 0.67 to 22.92 ng L-1 in RW, 0.029-28.13 µg kg-1 in irrigated soil, and <0.01-28.01 µg kg-1 in crops. The concentrations of N4-acetyl-sulfamethoxazole and triclosan were higher than those of other PPCPs, with respective concentrations of 14.39-31.44 ng L-1 and 15.93-26.23 ng L-1 in RW, 10.92-23.29 µg kg-1 and 20.22-28.13 µg kg-1 in irrigated soil and 17.92-28.01 µg kg-1 and 8.92-14.91 µg kg-1 in crops. However, the estimated threshold of toxicological concern (TTC) and hazard quotient (HQ) values revealed that the concentrations of N4-acetyl-sulfamethoxazole and triclosan in crops irrigated with RW should be considered a de minimis risk to human health. The concentrations of 11 PPCPs and one active metabolite in soils and crops and the calculated fruit bioconcentration factors (BCFs) did not display obvious increases associated with the duration of RW irrigation in real agricultural systems (P > 0.05). The concentrations of the studied PPCPs in the RW used for irrigation followed different patterns from the concentrations detected in the irrigated soils and crops. Although the concentrations of sulfamethoxazole, sulfisoxazole, sulfamethazine and trimethoprim in RW were higher than those of many other studied PPCPs, their respective values in the irrigated soils and crops did not display a similar tendency. The uptake and accumulation of PPCPs varied among the crop species (P < 0.05). Although PPCPs were detected in eggplant, long bean and wheat (BCFs: not applicable-1.67, 0.03-1.35 and 0.01-5.01, respectively), PPCPs accumulated at increased levels in cucumber (BCFs 0.03-18.98). The estimated TTC and HQ values showed that the consumption of crops irrigated long-term with RW presents a de minimis risk to human health. However, further studies with more PPCPs and additional crop species need to be conducted, the synergistic effects of chemical mixtures of multiple PPCPs and the toxic effects of PPCP metabolites should be elucidated to obtain more reliable information on the safety of wastewater reuse for irrigation.


Assuntos
Irrigação Agrícola , Cosméticos/análise , Preparações Farmacêuticas/análise , Poluentes do Solo/análise , Águas Residuárias/química , Pequim , China , Cosméticos/toxicidade , Produtos Agrícolas/química , Humanos , Medição de Risco , Poluentes do Solo/toxicidade , Sulfametoxazol/análogos & derivados , Sulfametoxazol/análise , Sulfametoxazol/toxicidade , Triclosan/análise , Triclosan/toxicidade
20.
Chemosphere ; 238: 124613, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31450110

RESUMO

Among pharmaceuticals, the occurrence of antibiotics in the environment is a subject of special concern due to their environmental impact, namely the development of bacterial resistance. Sulfamethoxazole (SMX) is one of the most commonly used antibiotics and it is regularly found, not only in effluents from sewage treatment plants (STPs), but also in the aquatic environment. Photodegradation appears as an alternative process for the removal of this type of pollutants from contaminated waters. In order to be used for a remediation purpose, its evaluation under continuous flow mode is essential, as well as the determination of the final effluent antibacterial activity, which were assessed in this work. As compared with batch operation, the irradiation time needed for SMX elimination under continuous flow mode sharply decreased, which is very advantageous for the target application. Moreover, the interrelation between SMX removal, mineralization and antibacterial activity was evaluated before and during photodegradation in ultrapure water. Although mineralization was slower than SMX removal, bacterial activity increased after SMX photodegradation. Such increase was also verified in environmental water matrices. Thus, this study has proven that photodegradation is an efficient and sustainable process for both (i) the remediation of waters contaminated with antibiotics, and (ii) the minimization of the bacterial resistance.


Assuntos
Antibacterianos/análise , Bactérias/efeitos dos fármacos , Fotólise , Sulfametoxazol/análise , Luz Solar , Poluentes Químicos da Água/análise , Antibacterianos/química , Antibacterianos/efeitos da radiação , Sulfametoxazol/química , Sulfametoxazol/efeitos da radiação , Poluentes Químicos da Água/química , Poluentes Químicos da Água/efeitos da radiação
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