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1.
J Environ Manage ; 301: 113894, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34638045

RESUMO

A biotic iron (Fe0) treatment system combined with mixed microorganisms was applied to remediate cadmium (Cd)-contaminated groundwater under the intervention of sulfate. Due to hydrogenotrophic desulfuration effect, severe iron corrosion was observed in this microbe-collaborative Fe0 system according to surface morphology analysis as lots of secondary minerals (e.g. magnetite, green rust and lepidocrocite) were generated, which was essential for Cd(II) adsorption and immobilization. The sulfate-mediated biotic Fe0 system thereafter achieved a significantly enhanced Cd(II) removal efficiency of 86.1%, over 3.3 times than that in the abiotic Fe0 system. Increasing initial sulfate concentration could improve the removal of cadmium, which further proved that hydrogenotrophic desulfuration played a key role for enhanced Cd removal. According to the experimental results and current reports, the mechanism of Cd(II) removal was revealed into three pathways including adsorption to secondary iron minerals, co-precipitation with iron (hydr)oxides and formation of cadmium sulfide precipitation. Increasing Fe0 dosages showed positive correlation to Cd(II) removal and neutral pH was preferred to sulfate-mediated biotic Fe0 corrosion. These results indicated that sulfate-mediated biotic Fe0 corrosion could greatly relieve the limitation of Fe0 in Cd(II) immobilization, which could be a promising method to eliminate Cd(II) pollution from groundwater.


Assuntos
Cádmio , Água Subterrânea , Cádmio/análise , Corrosão , Ferro , Sulfatos
2.
Chemosphere ; 286(Pt 1): 131649, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34325258

RESUMO

Sulfate-reducing bioreactors for sulfide production are the initial stage of processes targeting elemental sulfur recovery from sulfate-rich effluents. In this work, the principal reactions involved in glycerol fermentation and sulfate reduction using glycerol and its fermentation products as electron donors were assessed together with their specific consumption/production rates. A battery of batch activity tests with and without sulfate were performed with glycerol and with each fermentation product using a non-methanogenic but sulfidogenic granular sludge from an up-flow anaerobic sludge blanket (UASB) reactor operated under long-term while fed with crude glycerol. As a result, a mechanistic approach based on the experimental observations is proposed in this work. Glycerol was mainly fermented to 1,3-propanediol, ethanol, formate, propionate and acetate by fermentative bacteria. All organic intermediates were found to be further used by sulfate reducing bacteria (SRB) for sulfate reduction except for acetate. The most abundant genus detected under sulfidogenic conditions were Propionispora (15.2%), Dysgonomonas (13.2%), Desulfobulbus (11.6%) and Desulfovibrio (10.8%). The last two SRB genera accounted for 22.4% of the total amount of retrieved sequences, which were probably performing an incomplete oxidation of the carbon source in the sulfidogenic UASB reactor. As single substrates, specific sulfate reduction rates (SRRs) using low molecular weight (MW) carbon sources (formate and ethanol) were 39% higher than those using high-MW ones (propionate, 1,3-propanediol and butanol). However, SRRs in glycerol-fed tests showed that 1,3-propanediol played a major role in sulfate reduction in addition to formate and ethanol.


Assuntos
Reatores Biológicos , Glicerol , Biomassa , Oxirredução , Esgotos , Sulfatos , Eliminação de Resíduos Líquidos
3.
Chemosphere ; 286(Pt 2): 131779, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34364225

RESUMO

Anaerobic decolorization of azo dye in sulfate-containing wastewater has been regarded as an economical and effective method, but it is generally limited by the high concentration of azo dye and accumulation of toxic intermediates. To address this problem, Fe3O4 was added to one of the anaerobic reactors to investigate the effects on system performances. Results showed that AO7 removal rate, COD removal rate, and sulfate reduction were enhanced with the addition of Fe3O4 under various influent AO7 concentrations (153 mgCOD/L - 1787 mgCOD/L). According to the proposed pathway for the degradation of AO7, more intermediates (2-hydroxy-1,4-naphthoquinone, phthalide, 4-methylphenol) were produced in the presence of Fe3O4. The electron transfer capacity of sludge was also increased since Fe3O4 could stimulate to secrete humic acid-like organics in EPS. Microbial analysis showed that iron-reducing bacteria like Clostridium and Geobacter were also enriched, which were capable of azo dye and aromatic compounds degradation.


Assuntos
Compostos Azo , Microbiota , Anaerobiose , Reatores Biológicos , Corantes , Elétrons , Óxidos , Sulfatos
4.
Sci Total Environ ; 802: 149780, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34461478

RESUMO

In order to evaluate the potential risk of surface water acidification in regions with historically-elevated acid deposition and to measure the recovery of such ecosystems after policy changes, critical loads and their exceedances were estimated for 349 headwater streams across China using a modified SSWC model. Such a model considered the acid-neutralizing capacity derived from high base cation deposition and the robust retention of sulfate and nitrate. Results indicated that China's streams had higher critical loads (averaged at 4.7 keq·ha-1·yr-1) and were less sensitive to acid deposition as compared to Europe and North America. The proportion of surveyed streams with acid deposition exceeded critical load decreased from 40.4% in 2005 to 29.5% in 2018, indicating a significant decrease in risk of surface water acidification, and thus a benefit from the emission abatement in recent years. Nonetheless, a relatively high risk of acidification still existed in southeast China with lower critical loads and most critical load exceedances. More efforts should be put into implementing emission control policies in the future.


Assuntos
Ecossistema , Rios , China , Monitoramento Ambiental , Água Doce , Sulfatos , Enxofre/análise
5.
Sci Total Environ ; 804: 150072, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509848

RESUMO

Within the East African Rift System (EARS), the complex Ali-Sabieh aquifers system, located in the south of the Republic of Djibouti, was overexploited and subjected to anthropogenic and/or geogenic pollution with high concentrations of dissolved nitrate (up to 181 mg/l) and sulfates (up to 1540 mg/l). This study is the first undertaken on the hydrochemistry of this aquifer system, combining geochemical tools and multi-isotope - δ2H(H2O), δ18O(H2O), δ18O(SO4), δ34S(SO4), δ15N(NO3), δ18O(NO3), δ13C(DIC), and 14C- was used to decipher the origin and fate of different nitrate and sulfate sources to groundwater. The groundwater samples of the region show a chemical evolution from fresh Ca(Na)-bicarbonate to brackish Na-Cl , mainly due to water-rock interaction. The combined chloride and water isotope data show that evaporation and transpiration are present, with the latter occurring primarily in the shallow alluvial aquifer waters. Inspection of δ15N(NO3) vs. δ18O(NO3) and NO3/Cl vs. Cl diagrams show that dissolved nitrates are primarily of anthropogenic origin. In particular, higher nitrate concentrations may be related to animal manure used as organic fertilizers during agricultural activities. Sulfates are from a natural origin related to the interaction of water with gypsum of hydrothermal or sedimentary origin. SO4/Cl ratio and isotopic composition show that dissolved sulfates in saline and ancient groundwater of the Cretaceous sandstone aquifer (between 7.4 ± 2.2 and 5.8 ± 1.4 k-years before the present) are generated by interaction with gypsum from oxidation of pre-existing (Jurassic?) sulfides. This work highlight that isotopic ratios of the two molecules -δ18O(SO4), δ34S(SO4), δ15N(NO3), δ18O(NO3)- are not sufficient for tracing the origin of nitrate and sulfates in groundwater, but that a complete hydrogeochemical study is needed. In the absence of this, the relatively high concentration of chloride and sulfates could be wrongly linked to the anthropogenic source of nitrate (manure or sewage).


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Animais , Djibuti , Monitoramento Ambiental , Nitratos/análise , Isótopos de Nitrogênio/análise , Sulfatos , Poluentes Químicos da Água/análise
6.
Sci Total Environ ; 804: 150199, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34520918

RESUMO

Flooded condition enhances arsenic (As) mobility in paddy soils, posing an imminent threat to food safety and human health. Hence, iron oxyhydroxide and iron oxyhydroxide sulfate-modified coal gangue (CG-FeOH and CG-FeOS) were synthesized for remediation of As-contaminated paddy soils under a flooded condition. Compared to the control, CG-FeOH and CG-FeOS application decreased the soil pH by 0.10-0.80 and 0.13-1.63 units, respectively. CG-FeOH and CG-FeOS application significantly (P < 0.05) decreased available As concentration by 13.46-43.44% and 21.31-54.37%, respectively. CG-FeOH and CG-FeOS significantly (P < 0.05) reduced the non-specifically adsorbed and specifically adsorbed As fractions and increased As(V) proportion by 22.61-26.53% and 29.10-36.51%, respectively. Our results showed that CG-FeOH and CG-FeOS could change As geochemical fraction and valence state, consequently reducing available As concentration in paddy soils. Moreover, the sulfate could enhance the oxidation and co-precipitation of As with CG-FeOH. Compared to CG-FeOH, CG-FeOS was more effective in decreasing available As concentration and oxidizing As(III) to As(V). This study revealed that CG-FeOS is a potential amendment for As immobilization in paddy soils.


Assuntos
Arsênio , Oryza , Poluentes do Solo , Arsênio/análise , Carvão Mineral , Compostos Férricos , Humanos , Ferro/análise , Solo , Poluentes do Solo/análise , Sulfatos
7.
Sci Total Environ ; 804: 150229, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798748

RESUMO

High concentrations of PM2.5 in China have caused severe visibility degradation and health problems. However, it is still challenging to accurately predict PM2.5 and its chemical components in numerical models. In this study, we compared the inorganic aerosol components of PM2.5 (sulfate, nitrate, and ammonium (SNA)) simulated by the Weather Research and Forecasting model fully coupled with chemistry (WRF-Chem) model with in-situ data in a heavy haze-fog event during November 2018 in Nanjing, China. Comparisons show that the model underestimates sulfate concentrations by 81% and fails to reproduce the significant increase of sulfate from early morning to noon, which corresponds to the timing of fog dissipation that suggests the model underestimates the aqueous-phase formation of sulfate in clouds. In addition, the model overestimates both nitrate and ammonium concentrations by 184% and 57%, respectively. These overestimates contribute to the simulated SNA being 77.2% higher than observed. However, cloud water content is also underestimated which is a pathway for important aqueous-phase reactions. Therefore, we constrained the simulated cloud water content based on the Moderate Resolution Imaging Spectroradiometer (MODIS) Liquid Water Path observations. Results show that the simulation with MODIS-corrected cloud water content increases the sulfate by a factor of 3, decreases the Normalized Mean Bias (NMB) by 53.5%, and reproduces its diurnal cycle with the peak concentration occurring at noon. The improved sulfate simulation also improves the simulation of nitrate, which decreases the simulated nitrate bias by 134%. Although the simulated ammonium is still higher than the observations, corrected cloud water content leads to a decrease of the modelled bias in SNA from 77.2% to 14.1%. The strong sensitivity of simulated SNA concentration to the cloud water content provides an explanation for the simulated SNA bias. Hence, uncertainties in cloud water content can contribute to model biases in simulating SNA which are less frequently explored from a process-level perspective and can be reduced by constraining the model with satellite observations.


Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Sulfatos/análise , Água
8.
Sci Total Environ ; 804: 150241, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798751

RESUMO

Elevated concentrations of rare earth elements and yttrium (REE + Y) in acid mine drainage (AMD) attract worldwide attention. However, the source and control of REE + Y distribution patterns in AMD remain unclear. Water, rock, sediment, and sludge samples were collected from an ion-adsorption deposit site to investigate REE + Y concentrations and distributions. The heavy REE (HREE)-enriched patterns of the AMD resulted from preferential desorption of HREE in the clay-rich sediment strata, from which the REE + Y were ion-exchanged by an in-situ underground leaching process using ammonium sulfate brine. Free ions and sulfate complexes preserved REE + Y patterns and facilitated REE + Y mobility in the AMD leachate system. High concentrations of REE + Y occurred in the AMD, and decreased progressively through nitrification-denitrification and coagulation-precipitation procedures in a water treatment plant. Concentrations of REE + Y were one to three orders of magnitude higher in AMD than those in groundwater, and were negatively correlated (r2 = -0.72) with pH (3.8 to 8.7), suggesting that an acid desorption from minerals contributed the REE + Y to the AMD from the source rock. Normalized REE + Y patterns showed enrichments of HREE over light REE (LREE) and negative Ce anomaly. The distribution patterns were relatively constant for all water samples, despite their huge difference in REE + Y concentrations. This suggested a limited impact of preferential precipitation of LREE over HREE on REE + Y fractionations during neutralization. The potentially recoverable LREE and HREE were calculated to range between 1.12 kg/day and 3.37 kg/day, and between 1.29 kg/day and 3.76 kg/day, respectively. The findings reported in this study lend promise for efficient REE + Y recovery from AMD.


Assuntos
Metais Terras Raras , Poluentes Químicos da Água , Adsorção , Monitoramento Ambiental , Metais Terras Raras/análise , Sulfatos , Poluentes Químicos da Água/análise , Ítrio
9.
Environ Pollut ; 291: 118214, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34740292

RESUMO

Polychlorinated biphenyls (PCBs) have been demonstrated as a kind of the persistent organic pollutants (POPs) that could exert complicated influences towards metabolism in human bodies. Since hydroxylated polychlorinated biphenyls (OH-PCBs) are important metabolites of PCBs, our study focuses on investigating the potential inhibitory capability of OH-PCBs on four human sulfotransferase (SULT) isoforms. P-nitrophenol (PNP) was utilized as nonselective probe substrate for this study, and recombinant SULT isoforms were utilized as the enzyme resources. Ultra-performance liquid chromatography (UPLC)-UV detecting system was used to analyze PNP and its metabolite PNP-sulfate. As result, 100 µM of most tested OH-PCBs significantly inhibited the activity of four SULT isoforms. Concentration-dependent inhibition of OH-PCBs towards SULTs was found, and half inhibition concentration values (IC50) of some inhibition processes were determined. Inhibition kinetics (inhibition kinetic type and parameters) were determined using 4'-OH-PCB106 as the representative OH-PCB, SULT1B1 and SULT1E1 as representative SULT isoforms. The inhibition kinetic parameters (Ki) were 1.73 µM and 1.81 µM for the inhibition of 4'-OH-PCB106 towards SULT1B1 and SULT1E1, respectively. In silico docking simulation was utilized to analyze the inhibition capability of 2'-OH-PCB5, 4'-OH-PCB9, 2'-OH-PCB12 towards SULT1A3.All these results obtained in this study are helpful for further understanding the toxicity of PCBs.


Assuntos
Bifenilos Policlorados , Cromatografia Líquida , Humanos , Hidroxilação , Bifenilos Policlorados/toxicidade , Sulfatos , Sulfotransferases/metabolismo
10.
Int J Syst Evol Microbiol ; 71(11)2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34739365

RESUMO

A novel mesophilic, strictly anaerobic, chemolithoautotrophic sulphate-reducing bacterium, designated strain KT2T, was isolated from a deep-sea hydrothermal vent chimney at the Suiyo Seamount in the Izu-Bonin Arc. Strain KT2T grew at 25-40 °C (optimum 35 °C) and pH 5.5-7.0 (optimum 6.6) in the presence of 25-45 g l-1 NaCl (optimum 30 g l-1). Growth occurred with molecular hydrogen as the electron donor and sulphate, thiosulphate, and sulphite as the electron acceptors. The isolate utilized CO2 as the sole carbon source for chemolithoautotrophic growth on H2. Glycerol, succinate, fumarate, malate, glutamate, or casamino acids could serve as an alternative electron donor in the presence of CO2. Malate, citrate, glutamate, and casamino acids were used as fermentative substrates for weak growth. The G+C content of genomic DNA was 46.1 %. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain KT2T is a member of the family Desulfobulbaceae, showing a sequence similarity of 94.3 % with Desulforhopalus singaporensis. Phylogenomic analysis based on concatenated 156 single-copy marker genes confirmed the same topology as the 16S rRNA gene phylogeny. The ANI and AAI values between strain KT2T and related genera of the family Desulfobulbaceae were 65.6-68.6 % and 53.1-62.9 %. Based on the genomic, molecular, and physiological characteristics, strain KT2T represents a novel genus and species within the family Desulfobulbaceae, for which the name Desulfomarina profundi gen. nov., sp. nov. is proposed, with KT2T (=JCM 34118T = DSM 111364T) as the type strain.


Assuntos
Fontes Hidrotermais , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Deltaproteobacteria , Ácidos Graxos/química , Hidrogênio , Oxirredução , Filogenia , RNA Ribossômico 16S/genética , Água do Mar , Análise de Sequência de DNA , Sulfatos
11.
J Water Health ; 19(5): 796-807, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34665772

RESUMO

Sulfate radical (•SO4-)-based advanced oxidation processes are widely used for wastewater treatment. This study explored the potential use of UV/persulfate (UV/PS) system for the degradation of 17ß-estradiol (E2). The pH of the reaction system can affect the degradation rate of E2 by UV/PS and the optimum pH was 7.0; Br- and Cl- in water can promote the degradation rate, HCO3- has an inhibitory effect on the reaction, SO42- and cations (Na+, Mg2+, K+) have no effect on the degradation rate. The degradation of E2 by UV/PS was a mineralization process, with the mineralization rate reaching 90.97% at 8 h. E2 in the UV/PS system was mainly degraded by hydroxylation, deoxygenation, and hydrogenation. E2 reaction sites were mainly located on benzene rings, mainly carbonylation on quinary rings, and bond breakage between C10 and C5 resulted in the removal of benzene rings and carboxyl at C2 and C3 sites. In the presence of halogen ions, halogenated disinfection by-products were not formed in the degradation process of E2 by UV/PS. E2 in the UV/PS system could inhibit the formation of bromate. The results of this study suggest that UV/PS is a safe and reliable method to degrade E2.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Estradiol , Oxirredução , Sulfatos , Raios Ultravioleta , Água , Poluentes Químicos da Água/análise
12.
Int J Mol Sci ; 22(19)2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34639095

RESUMO

A 4-nitro-L-phenylalanine scaffold was used to construct effective ion pair receptors capable of binding anions in an enhanced manner with the assistance of alkali metal cations. A benzocrown ether was linked to a receptor platform via the amide function so as to support the squaramide function in anion binding and to allow all three NHs to act simultaneously. The binding properties of the receptors were determined using UV-vis, 1H NMR, 2D NMR, and DOSY spectroscopy in MeCN and in the solid state by X-ray measurements. Ion pair receptor 2 was found to interact with the most strongly with salts, and the removal of its key structural elements was shown to hinder the receptor action. The amide proton was recognized to switch from having involvement in an intramolecular hydrogen bond to interacting with anions upon complexation. Apart from carboxylates, which promote deprotonation, and other monovalent salts creating 1:1 complexes with the receptor, more complex equilibria were established upon the complexation of 2 with sulfates. Receptor 2 was shown to be capable of the extraction of ion pairs from the aqueous to organic phase and of the cation-enhanced transport chloride and sulfate anions across a bulk chloroform membrane. These features may open the door for its use in regulating ion concertation under interfacial conditions and acting as a potential drug to treat channelopathies.


Assuntos
Aminoácidos/metabolismo , Ânions/metabolismo , Cátions/metabolismo , Sais/metabolismo , Sulfatos/metabolismo , Aminoácidos/química , Ânions/química , Cátions/química , Cristalografia por Raios X , Ligação de Hidrogênio , Modelos Moleculares , Estrutura Molecular , Sais/química , Sulfatos/química
13.
Ecotoxicol Environ Saf ; 226: 112845, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34627042

RESUMO

Avian biovector transport is an important mechanism for the movement of contaminants and nutrients to remote locations, usually bird colonies, through excretion, molting and decomposition of carcasses. Methylmercury (MeHg) is a bioaccumulative neurotoxin and endocrine disruptor which is present in many remote ecosystems. We collected guano samples biweekly from a herring gull (Larus smithsoniansus) colony over two summers and analyzed MeHg, total mercury (THg), water-extractable phosphate (PO43-) and sulfate (SO42-). Concentrations of THg in guano declined through the summer months while %MeHg significantly increased (ranging from 12% to 100% of THg), suggesting a switch in diet as gull nutritional needs or food availability changed through the summer. The percentage of PO43- in dry guano increased throughout the summer (ranging from 2.8% to 4.4% of dry weight) and SO42- varied throughout the season (ranging from 0.1% to 0.8% of dry weight). These data indicate that gulls are transporting considerable amounts of MeHg, PO43-, and likely other contaminants to Big Meadow Bog, Nova Scotia.


Assuntos
Charadriiformes , Mercúrio , Compostos de Metilmercúrio , Poluentes Químicos da Água , Animais , Ecossistema , Monitoramento Ambiental , Mercúrio/análise , Fosfatos , Sulfatos , Poluentes Químicos da Água/análise , Áreas Alagadas
14.
Water Sci Technol ; 84(8): 1981-1996, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34695025

RESUMO

Discharge of acid mine drainage (AMD) from abandoned coal mines of the YuDong catchment in Kaili City, Guizhou Province, China, has severely damaged local ecological environments. In this study, a laboratory-scale dispersed alkaline substrate (DAS) was studied for the treatment of simulated AMD. The experimental conditions and reaction mechanisms were preliminarily explored. The treatment effect and variation law of vertical effluent water quality of the experimental conditions were thoroughly analysed. The results indicated that small-sized limestone (diameter 5-7 mm) having a 20:1 mixture ratio with shavings and minimum HRT of 20 hours result in increasing effluent pH from 3.5 to 6.6, achieving 66.2% and 99.1% removal of Fe and Al, respectively. There were obvious differences in each reaction layer for the removal of various pollutants from AMD along the depth by DAS, the main reaction zone was first 20-30 cm of the reaction column. The removal process of metal ions and sulfate was accompanied by bio-mineralization reaction. This test provided a valuable support for the local practical engineering applications, enriched the AMD processing technology experimental cases, and provided reference for the treatment technology of similar polluted areas.


Assuntos
Mineração , Poluentes Químicos da Água , Ácidos , Carvão Mineral , Concentração de Íons de Hidrogênio , Metais , Sulfatos , Poluentes Químicos da Água/análise
15.
Water Res ; 206: 117673, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34624655

RESUMO

Souring is the unwanted formation of hydrogen sulfide (H2S) by sulfate-reducing microorganisms (SRM) in sewer systems and seawater flooded oil reservoirs. Nitrate treatment (NT) is one of the major methods to alleviate souring: The mechanism of souring remediation by NT is stimulation of nitrate reducing microorganisms (NRM) that depending on the nitrate reduction pathway can outcompete SRM for common electron donors, or oxidize sulfide to sulfate. However, some nitrate reduction pathways may challenge the efficacy of NT. Therefore, a precise understanding of souring rate, nitrate reduction rate and pathways is crucial for efficient souring management. Here, we investigate the necessity of incorporating two thermodynamic dependent kinetic parameters, namely, the growth yield (Y), and FT, a parameter related to the minimum catabolic energy production required by cells to utilize a given catabolic reaction. We first show that depending on physiochemical conditions, Y and FT for SRM change significantly in the range of [0-0.4] mole biomass per mole electron donor and [0.0006-0.5], respectively, suggesting that these parameters should not be considered constant and that it is important to couple souring models with thermodynamic models. Then, we highlight this further by showing an experimental dataset that can be modeled very well by considering variable FT. Next, we show that nitrate based lithotrophic sulfide oxidation to sulfate (lNRM3) is the dominant nitrate reduction pathway. Then, arguing that thermodynamics would suggest that S° consumption should proceed faster than S0 production, we infer that the reason for frequently observed S0 accumulation is its low solubility. Last, we suggest that nitrate based souring treatment will suffer less from S0 accumulation if we (i) act early, (ii) increase temperature and (iii) supplement stoichiometrically sufficient nitrate.


Assuntos
Bactérias , Nitratos , Campos de Petróleo e Gás , Sulfatos , Temperatura
16.
Huan Jing Ke Xue ; 42(10): 4678-4686, 2021 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-34581110

RESUMO

The particulate matter emitted from coal-fired power plants includes condensable particulate matter(CPM) and filterable particulate matter(FPM). By analyzing the concentration of SO42-and NO3- components of CPM and FPM in the inlet/outlet of wet flue gas desulfurization(WFGD) and the outlet of wet electrostatic precipitator(WESP) from 7 ultra-low emission coal-fired power plants, the variation laws and transformation characteristics were investigated. The results showed that the concentration of SO42- and NO3- of CPM decreased after WFGD, with reduction rates of 43.12%-86.84% and 17.99%-91.58%, respectively, which were different from the conversion trend of FPM. The concentrations of SO42- and NO3- of CPM increased after WESP, with reduction rates of 21.05%-424.65% and 13.51%-298.37%, respectively, which were also different from that of FPM. In the WFGD system, CPM could be transformed into FPM due via condensation and aggregation under the decreasing temperature and increasing of humidity of the flue gas. In the WESP system, SO2 and NO2 in the flue gas combine with water vapor in a redox reaction, which promotes the generation of SO42- and NO3- in CPM through synergistic action.


Assuntos
Poluentes Atmosféricos , Material Particulado , Poluentes Atmosféricos/análise , Carvão Mineral/análise , Nitratos , Material Particulado/análise , Centrais Elétricas , Sulfatos
17.
Huan Jing Ke Xue ; 42(10): 4807-4814, 2021 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-34581123

RESUMO

Viruses in the aquatic environment have strong resistance to common disinfection techniques. To contribute to the development of efficient virus inactivation technologies, the characteristics and mechanisms of virus inactivation in a UV activated sodium persulfate(UV/PS) system were studied. The inactivation rate and kinetic characteristics of bacteriophage MS2 in water samples by the UV/PS were studied. The effects of PS dosage, pH, and the initial concentration of bacteriophages on the inactivation effect were also investigated. Furthermore, the morphologies of phages before and after UV/PS treatment were observed by transmission scanning electron microscope, and the free radicals in the reaction system were identified by electron paramagnetic resonance spectroscopy. By means of a free radical quenching experiment, the contribution rate of various factors in the UV/PS system to phage inactivation was also analyzed and calculated. The results showed that when the UV irradiation intensity was 160 µW·cm-2, the phage MS2 of 4.39 lg could be removed after UV/PS treatment for 4 min, which was 1.44 lg higher than that of the same UV dose alone. The inactivation of phage MS2 by the UV/PS system was in accordance with the first-order kinetic model. Increasing the initial concentration of PS in the system significantly improved the inactivation rate of phages, while pH and the initial concentration of phages had little effect on the inactivation rate. UV/PS treatment damages the capsid of phages and promotes the aggregation of phage particles. The presence of SO4-· and·OH in the UV/PS system was an important factor for the inactivation of MS2 phages. Finally, ·OH contributed more to MS2 phage inactivation than SO4-·.


Assuntos
Levivirus , Purificação da Água , Compostos de Sódio , Sulfatos , Raios Ultravioleta , Inativação de Vírus , Água
18.
Artigo em Inglês | MEDLINE | ID: mdl-34501509

RESUMO

Acid sulfate soils contain sulfide minerals that have adverse environmental effects because they can lead to acidic drainage and prevent the establishment of vegetation. The current study examined the effect of a novel method for the restoration of these soils and the promotion of germination and plant growth. Thus, we isolated two strains of phosphate solubilizing bacteria, Methylobacterium sp. PS and Caballeronia sp. EK, characterized their properties, and examined their effects in promoting the growth of tomato plants (Lycopersicon esculentum L.) in acid sulfate soil. Compared with untreated control soil, treatment of acid sulfate soils with these bacterial strains led to increased seed germination, growth of plants with more leaves, and plants with greater levels of total-adenosine tri-phosphate (tATP). Relative to the untreated control soil, the addition of Caballeronia sp. EK led to a 60% increase in seed germination after 52 days, growth of plants with more than 3 times as many leaves, and a 45.2% increase in tATP after 50 days. This strain has potential for use as a plant biofertilizer that promotes vegetation growth in acid sulfate soils by improving the absorption of phosphorous.


Assuntos
Lycopersicon esculentum , Bactérias , Germinação , Fosfatos , Solo , Sulfatos
19.
Food Res Int ; 148: 110562, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34507721

RESUMO

Sea cucumber Stichopus japonicus has been consumed as high-valued seafood in Asian, and its sulfated polysaccharide (SCSPsj) has been inferred to benefit the host health via modulating gut microbiota composition. The present study compared the responses of gut microbiota communities from different donors to SCSPsj, and the key bacteria were identified by 16S rRNA gene sequencing analysis and in vitro fermentation with specific bacteria. Gut microbiota communities from 6 donors (A ~ F) utilized the polysaccharides to different degrees in vitro fermentation. Further comparison of Samples A and C demonstrated that Sample C with the relatively strong SCSPsj utilization capability possessed more Parabacteroides while Sample A contained more Bacteroides. Further in vitro fermentation of SCSPsj with 10 Parabacteroides and Bacteroides species suggests that Parabacteroides distasonis, enriched in Sample C, plays a critical role in the utilization of the polysaccharides. Moreover, short chain fatty acids and the metabolite profiles of Samples A and C were also compared, and the results showed that more beneficial metabolites were accumulated by the microbiota community consuming more sulfated sea cucumber polysaccharides. Our findings revealed that certain key members of gut microbiota, such as Parabacteroides distasonis, are critical for SCSPsj utilization in gut so as to influence the benefits of the polysaccharide supplement for host. Thus, to obtain better functional outcome for sulfated sea cucumber polysaccharides and sea cucumber, more attention needs to be paid to the effects of inter-individual differences in microbiota community structure.


Assuntos
Microbioma Gastrointestinal , Pepinos-do-Mar , Animais , Bacteroidetes , Fermentação , Polissacarídeos , RNA Ribossômico 16S/genética , Sulfatos
20.
Water Res ; 204: 117628, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34507021

RESUMO

Both biological sulfate reduction process and sulfur reduction process are attractive technologies for metal-laden wastewater treatment. However, the acidity stress of metal-laden wastewater could affect the sulfidogenic performance and the microbial community, weaken the stability, efficiency and cost-effectiveness of the biological sulfidogenic processes (BSP). In this study, long-term lab-scale trials were conducted with a sulfate-reducing bioreactor and a sulfur-reducing bioreactor to evaluate the effects of acidity on sulfidogenic activities and the microbial community of the BSP. In the 300-day trial, the sulfate-reducing bacteria (SRB)-driven BSP was stable in terms of sulfidogenic performance and microbial community with the decline of pH, while the sulfur-reducing bacteria (S0RB)-driven BSP achieved high-rate and low-cost sulfide production under neutral conditions but unstable under acidic conditions. With the decline of pH, the sulfide production rate (SPR) of the SRB-driven BSP stably increased from 30 to 83 mg S/L-h; while it decreased from 56 to 37 mg S/L-h in the S0RB-driven BSP with high fluctuation. The results of estimation were consistent with the thermodynamical calculations, in which the sulfur reduction process showed a better performance at pH 5-7, while the sulfate reduction process might gain more energy when pH<5. The stable sulfidogenic performance and microbial community diversity of the SRB-driven BSP could be attributed to the alkalinity produced in sulfate reduction to buffer the acidic stress. In comparison, the microbial community in the S0RB-driven BSP was significantly re-shaped by acidity stress, and the predominant sulfidogenic bacterium changed from Desulfovibrio at neutral condition, to Desulfurella at pH≤5.4. The stability of the microbial community significantly affected the SPR and the operational cost. Nevertheless, the organic consumption for sulfide production of the S0RB-driven BSP was still less than the SRB-driven BSP even in acidic conditions. Collectively, the S0RB-driven BSP was recommended under neutral or mild acid conditions, while the SRB-driven BSP was more suitable under fluctuating pH conditions, especially at low pH. Overall, this study presented the long-term performance of SRB- and S0RB-driven BSP under varying pH conditions, and provided guidance to determine the suitable BSP and operational cost for different metal-laden wastewater.


Assuntos
Enxofre , Águas Residuárias , Concentração de Íons de Hidrogênio , Metais , Sulfatos
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