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1.
Extremophiles ; 25(1): 85-99, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33416983

RESUMO

Aquatic environments of volcanic origin provide an exceptional opportunity to study the adaptations of microorganisms to early planet life conditions. Here, we characterized the prokaryotic communities and physicochemical properties of seepage sites at the bottom of the Poas Volcano crater and the Agrio River, two geologically related extremely acidic environments located in Costa Rica. Both locations hold a low pH (1.79-2.20) and have high sulfate and iron concentrations (Fe = 47-206 mg/L, SO42- = 1170-2460 mg/L), but significant differences in their temperature (90.0-95.0 ºC in the seepages at Poas Volcano, 19.1-26.6 ºC in Agrio River) and in the elemental sulfur content. Based on the analysis of 16S rRNA gene sequences, we determined that Sulfobacillus spp. represented more than half of the sequences in Poas Volcano seepage sites, while Agrio River was dominated by Leptospirillum and members of the archaeal order Thermoplasmatales. Both environments share some chemical characteristics and part of their microbiota, however, the temperature and the reduced sulfur are likely the main distinguishing features, ultimately shaping their microbial communities. Our data suggest that in the Poas Volcano-Agrio River system there is a common metabolism but with specialization of species that adapt to the physicochemical conditions of each environment.


Assuntos
Temperatura Alta , Microbiota , Filogenia , Enxofre , Ácidos , Archaea/classificação , Bactérias/classificação , Costa Rica , Concentração de Íons de Hidrogênio , RNA Ribossômico 16S/genética , Rios , Erupções Vulcânicas
2.
Waste Manag ; 121: 276-285, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33388650

RESUMO

Sulfur (S) is an abundant and redox-active element in urban wastewater systems and plays a critical role in both the wastewater and sludge treatment processes. This study comparatively characterized the transformation of S and several closely associated metals (Cu, Zn, and Fe) during pyrolysis (250 to 750 °C) and hydrothermal carbonization (HTC, 150 to 275 °C) treatments of sewage sludge. S, Fe, Zn, and Cu K-edge X-ray absorption spectroscopy was applied to quantitatively evaluate the fate of S and contribution of different S species in regulating metal speciation. During pyrolysis, aliphatic-S and sulfonate were preferentially degraded at low temperature (below 350 °C) and sulfate was thermochemically reduced at temperature above 450 °C, while metal sulfides (up to 27%) and thiophenes (up to 70%) were increasingly formed. Similar to the pyrolysis process, metal sulfides (up to 40% at temperature above 200 °C) and thiophenes were formed during HTC. The degradation of thiols and organic sulfide, as well as sulfate reduction, released sulfide and strongly affected metal speciation. For example, almost all Cu and half of Zn were transformed into Cu-Fe- or Zn-Fe-sulfides during HTC, whereas they were partially desulfidized during pyrolysis. High abundance of reduced S species (S-1 and S-2) in hydrochars may contribute to their strong reductive adsorption of Cr(VI). Results from this work reveal the thermochemical reactions driving the transformations of S and its associated metals during pyrolysis and HTC. The results provide fundamental knowledge for selecting thermochemical sludge treatment techniques for value-added applications of the products.


Assuntos
Metais Pesados , Esgotos , Pirólise , Enxofre , Águas Residuárias , Espectroscopia por Absorção de Raios X
3.
Ecotoxicol Environ Saf ; 208: 111643, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396163

RESUMO

Sulfur (S) can play essential roles in protecting plants against abiotic stress, including heavy metal toxicity. However, the effect of this nutrient on plants exposed to barium (Ba) is still unknown. This study was designed to evaluate the S supply on oxidative stress and the antioxidant system of Tanzania guinea grass under exposure to Ba, grown in a nutrient solution under greenhouse conditions. It was studied the influence of S/Ba combinations in nutrient solution on oxidative stress indicators (hydrogen peroxide, malondialdehyde, and proline) and antioxidant enzyme activities (superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase, and glutathione reductase). The treatments consisted in thirteen S/Ba combinations in the nutrient solution (0.1/0.0; 0.1/5.0; 0.1/20.0; 1.0/2.5; 1.0/10.0; 1.9/0.0 - control; 1.9/5.0; 1.9/20.0; 2.8/2.5; 2.8/10.0; 3.7/0.0; 3.7/5.0 and 3.7/20.0 mM of S and Ba, respectively). The plants were grown for two growth periods, which consisted of fourteen days of S supply and the eight days of Ba exposure each one. The severe S deficiency decreased the superoxide dismutase activity, regardless of Ba exposure in recently expanded leaves and culms plus sheaths. However, supplemental S supply (above 1.9 mM S, which corresponds to S supply adequate to plant growth) it improved the superoxide dismutase activity in these tissues under high Ba concentrations. Conversely, the severe S deficiency increased the activities of catalase, ascorbate peroxidase, and glutathione reductase in grass leaves slightly, without Ba exposure influence. It was observed that the supplemental S supply also induced the guaiacol peroxidase activity and proline production in culms plus sheaths under high Ba rates, showing values until 2.5 and 3.1 folds higher than the control treatment, respectively. In plants under exposure to 20.0 mM Ba, the supplemental S supply decreased the malondialdehyde content in culms plus sheaths in 17% compared to 1.9 mM S. These results indicate that supplemental S supply can mitigate Ba toxicity in Tanzania guinea grass, mainly by improving superoxide dismutase and guaiacol peroxidase activities, and proline metabolism.


Assuntos
Antioxidantes/metabolismo , Bário/toxicidade , Panicum/efeitos dos fármacos , Prolina/metabolismo , Enxofre/farmacologia , Fertilizantes , Estresse Oxidativo/efeitos dos fármacos , Panicum/crescimento & desenvolvimento , Panicum/metabolismo , Peroxidase/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Superóxido Dismutase/metabolismo
4.
Bioresour Technol ; 319: 124248, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33254470

RESUMO

A new solution for fossil raw materials desulfurization based on a hybrid chemical-biocatalytic scheme with biogas and sulfide production is proposed.·H2O2, formic acid and Na2MoO4 were used for petroleum or oil fractions pre-oxidation. Ethanol or dimethylformamide was used as extractant to remove sulfur-contained compounds from pre-oxidized straight-run diesel oil fraction, non-hydro treated vacuum gas oil, gas condensate or crude oil. Compositions of cells (anaerobic sludge, Desulfovibrio vulgaris, Clostridium acetobutilycum, Rhodococcus ruber, Rhodococcus erythropolis) were specially developed, immobilized in poly(vinyl alcohol) cryogel and used for methanogenic treatment of sulfur-containing extracts, diluted with phosphate buffer (pH 7.2) and hydrolysates of renewable raw materials. The sulfur coming into the reactor with the extracts was 100% converted to inorganic sulfide or cell biomass. The ratio of methane in the biogas was 68-76%. Bioluminescent express-methods were used to control the possible toxicity of media and metabolic activity of cells used as biocatalysts.


Assuntos
Petróleo , Anaerobiose , Biotransformação , Peróxido de Hidrogênio , Extratos Vegetais , Rhodococcus , Enxofre
5.
Chemosphere ; 262: 128361, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182109

RESUMO

Although Cd is threatening to the environment, animal, and human, the eco-friendly approach to mitigate the Cd-toxicity in alfalfa was barely studied. Therefore, this study aims at elucidating the role of S, a crucial macroelement, in alleviating Cd toxicity in alfalfa plants. The supplementation of S in Cd-stressed alfalfa reversed the detrimental effect on plant biomass, chlorophyll synthesis, and protein concentration. Interestingly, S surplus restored the photosynthetic kinetics, such as Fv/Fm, Pi_ABS, and Mo values in leaves of Cd-stressed alfalfa. Further, Cd-induced adverse effect on membrane stability, cell viability, and redox status was restored due to S under Cd stress. The exogenous S not only increased S status and the expression of sulfate transporters (MsSULRT1;2 and MsSULTR1;3), but also decreased the Cd concentration in the shoot by retaining elevated Cd in root tissue. Further analysis revealed the upregulation of MsGS (glutathione synthetase) and MsPCS1 (phytochelatin synthase) genes along with the increased concentration of glutathione and phytochelatin, predominantly in roots subjected to S surplus under Cd stress. The subcellular Cd analysis showed elevated Cd in the cell wall but not in the vacuole. It suggests that S-induced elevated glutathione enables the phytochelatin to bind with excess Cd leading to subcellular sequestration in the cell wall of roots. Also, S stimulates the S-metabolites and GR enzyme that coordinately counteracts Cd-induced oxidative damage. These findings can be utilized to popularize the application of S and to perform breeding/transgenic experiments to develop Cd-free forage crops.


Assuntos
Cádmio/toxicidade , Glutationa/metabolismo , Medicago sativa/fisiologia , Fitoquelatinas/metabolismo , Poluentes do Solo/toxicidade , Enxofre/toxicidade , Aminoaciltransferases , Cádmio/metabolismo , Parede Celular/metabolismo , Medicago sativa/metabolismo , Oxirredução , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Poluentes do Solo/metabolismo , Enxofre/metabolismo
6.
J Environ Sci (China) ; 99: 119-129, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33183689

RESUMO

Activated carbon (AC) has been widely used in the removal of SO2 from flue gas owing to its well-developed pore structure and abundant functional groups. Herein, the effect of alkali/alkaline earth metals on sulfur migration was investigated based on the dynamic adsorption and temperature programmed desorption experiment. The adsorption and desorption properties of six types of AC (three commercial and three laboratory-made) were carried out on a fixed-bed experimental device, and the physical and chemical properties of samples were determined by X-ray fluorescence, X-ray diffraction, scanning electron microscopy/energy dispersive X-ray, and X-ray photoelectron spectroscopy analysis. The experimental results showed that the adsorbed SO2 cannot be completely desorbed by increasing the regeneration temperature (350 - 850°C), while the SO2 fixed in the AC combines with the Ca-based minerals in the ash to form a stable sulfate. For different samples, higher ash content, higher CaO content in the ash and a more developed pore structure lead to a higher SO2 fixation rate. Moreover, the multiple adsorption-desorption cycles experiment showed that the effect of SO2 fixation is mainly reflected in the first cycle, after which the adsorption and desorption amount are approximately the same. This study elucidates the effect of alkali/alkaline earth metals on the adsorption-desorption cycle of AC, which provides a deeper understanding of sulfur migration in the AC flue gas desulfurization process.


Assuntos
Carvão Vegetal , Dióxido de Enxofre , Adsorção , Álcalis , Metais Alcalinoterrosos , Enxofre
7.
Ecotoxicol Environ Saf ; 207: 111216, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32916525

RESUMO

Low concentrations of selenium (Se) are beneficial for plant growth. Foliar Se application at high concentrations is toxic to plants due to the formation of reactive oxygen species (ROS). This study characterized Se toxicity symptoms using X-ray fluorescence (XRF) technique in response to foliar Se application in cowpea plants. Five Se concentrations (0, 10, 25, 50, 100 e 150 g ha-1) were sprayed on leaves as sodium selenate. The visual symptoms of Se toxicity in cowpea leaves were separated into two stages: I) necrotic points with an irregular distribution and internerval chlorosis at the leaf limb border (50-100 g ha-1); II) total chlorosis with the formation of dark brown necrotic lesions (150 g ha-1). Foliar Se application at 50 g ha-1 increased photosynthetic pigments and yield. Ultrastructural analyses showed that Se foliar application above 50 g ha-1 disarranged the upper epidermis of cowpea leaves. Furthermore, Se application above 100 g ha-1 significantly increased the hydrogen peroxide concentration and lipid peroxidation inducing necrotic leaf lesions. Mapping of the elements in leaves using the XRF revealed high Se intensity, specifically in leaf necrotic lesions accompanied by calcium (Ca) as a possible attenuating mechanism of plant stress. The distribution of Se intensities in the seeds was homogeneous, without specific accumulation sites. Phosphorus (P) and sulfur (S) were found primarily located in the embryonic region. Understanding the factors involved in Se accumulation and its interaction with Ca support new preventive measurement technologies to prevent Se toxicity in plants.


Assuntos
Selênio/metabolismo , Vigna/metabolismo , Peroxidação de Lipídeos , Fósforo/análise , Fotossíntese , Folhas de Planta/química , Sementes/química , Ácido Selênico/análise , Selênio/análise , Enxofre/análise
8.
Food Chem ; 338: 127785, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32798825

RESUMO

Patulin (PAT) contaminant causes severe food safety issue throughout apple industry. Although adsorption is the feasible approach to remove PAT, the limited adsorption capacity and separation difficulty of most adsorbent is the major drawback that remains to be overcome. Here GO-SH doped aerogel was prepared and used for removal PAT from apple juice. The intrinsic porous of the aerogel and abundant active sites including -COOH, -NH2 and -SH offered the PAT adsorption capacity of 24.75 µg/mg that superior to most reported adsorbents. Furthermore, it could reduce 89 ± 1.23% PAT in real apple juice without juice quality deterioration and cytotoxicity. Importantly, the aerogel with good mechanical strength and structure stability could endure the complex juice solution so that there was no any residue after convenient separation of the aerogel, which proved that the proposed aerogel was a promising adsorbent to be applied to apple juice industry for PAT removal.


Assuntos
Sucos de Frutas e Vegetais/análise , Grafite/química , Malus/química , Patulina/química , Patulina/isolamento & purificação , Enxofre/química , Adsorção , Contaminação de Alimentos/análise , Géis
9.
Sci Total Environ ; 751: 141869, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32882542

RESUMO

Black bloom occurs frequently in eutrophic waters. We investigated the conditions promoted the formation of black bloom via in-situ measurement in two aquatic microcosms and the effects of black bloom on the bacterial community composition. Although larger changes in dissolved oxygen (DO) were detected in the Hydrilla verticillata-dominated microcosm over the 90-day simulation, black bloom occurred more readily in the phytoplankton-dominated than macrophyte-dominated microcosm under conditions of O2 depletion and temperature above 30 °C. The sediment bacterial community composition shifted after black bloom; the relative abundance of Thiobacillus and Sideroxydans, which oxidize iron (Fe) and sulfur (S), decreased by 47% and 48%, respectively, in the phytoplankton-dominated microcosm and by 18% and 20% in the macrophyte-dominated microcosm. By contrast, Desulfatiglans increased by 13% and 19%, respectively, after black bloom. Furthermore, inter-taxa correlations remarkably changed according to co-occurrence network analysis. Thirty-six different taxa from the phylum to the genus level were identified as biomarkers of sediments collected before and after the black bloom event. Most of these biomarkers are related to Fe/S cycling in aquatic ecosystems.


Assuntos
Sedimentos Geológicos , Ferro , Bactérias , Ecossistema , Eutrofização , Ferro/análise , Lagos , Enxofre
10.
Sci Total Environ ; 754: 142180, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920410

RESUMO

Residues from hydrogen sulfide (H2S) removal in biogas filters contain sulfur (S) in various forms (sulfate, sulfide, elemental S) that, if properly stored, is potentially valuable as crop fertilizer. We investigated 1) the turnover of the S compounds from filter materials during storage in untreated and digested cattle manure (CM), and 2) the S fertilizer replacement value (SFRV) of the filter materials applied in pure form or mixed manure with and without storage. The S filter materials from four H2S removal processes (biological and physical-chemical) containing mostly sulfate and/or elemental S were added to untreated CM or digested CM and stored at 10 °C for six months. Afterwards, a pot experiment was established to assess the S availability in an oil-seed rape (Brassica napus) crop. Microbial reduction of sulfate into sulfide took place rapidly after 69 days storage of untreated CM. A lower reduction rate was observed in digested CM mixtures. After six months, 68% and 32% of the initial sulfate content were still present in mixtures containing the S filter materials from biological desulfurization with digested CM and untreated CM, respectively. Sulfate reduction was inhibited for 120 days when digested CM was mixed with S saturated solution from an ash filter, probably due to high pH (≥8.2) and redox potential (>-100 mV) levels. Oppositely, elemental S was immediately and simultaneously both reduced and oxidized. Relatively low losses of total S were observed during the present storage conditions. Despite S turnover, the SFRV of CM and digested CM significantly increased from 15-19% (of total S applied) to 56-90% when S filter materials were added. The storage of S filter materials in digested manure reduced the risk of sulfide production and potential S volatilization. The S filter materials were a valuable source of plant-available S.


Assuntos
Sulfeto de Hidrogênio , Esterco , Animais , Biocombustíveis , Reatores Biológicos , Bovinos , Sulfeto de Hidrogênio/análise , Sulfatos , Enxofre
11.
Cell Calcium ; 93: 102323, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33316586

RESUMO

The store-operated calcium channels Orai1-3 form extraordinary long and funnel like pores, in stark contrast to a classical pore loop architecture. A hydrophobic segment centrally located in the Orai pore controls gating. Here, we comment on a recent work that describes decisive binding between three residues that controls the open and closed conformation of Orai channels.


Assuntos
Canais de Cálcio , Ativação do Canal Iônico , Canais de Cálcio/metabolismo , Proteína ORAI1/genética , Proteína ORAI1/metabolismo , Molécula 1 de Interação Estromal/metabolismo , Enxofre
12.
Waste Manag ; 121: 117-126, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33360811

RESUMO

High-sulfur mixed fly ash residues from semi-dry flue gas desulfurization units in coal-fired power plants are unsuitable for use as supplementary cementitious material (SCM) for concrete production or carbon dioxide utilization. In this work, we explore the potential for upcycling a representative spray dry absorber ash (10.44 wt% SO3) into concrete-SCM by selective sulfur removal via weak acid dissolution while simultaneously exploring the possibility for CO2 capture. Towards this effort, parametric studies varying liquid-to-solid ratio, acidity, and CO2 pressure were conducted in a batch reactor to establish the sulfur removal characteristics in de-ionized water, nitric acid, and carbonic acid, respectively. The dissolution studies show that the leaching of sulfur from calcium sulfite hemihydrate, which is the predominant S phase, is rapid and achieves a concentration plateau within 5 min, and subsequently, appears to be controlled by the primary mineral solubility. Preferential S removal was sufficient to meet SCM standards (e.g., 5.0 wt% as per ASTM C618) using all three washing solutions with 0.62-0.72 selectivity (S^), defined as the molar ratio of S to Ca in the leachate, for a raw fly ash with bulk S^ = 0.3. Acid dissolution with 1.43 meq/g of ash or under 5 atm CO2 retained > 18 wt% CaO and other Si-, Al-rich phases in the fly ash. Based on the experimental findings, two sulfur removal schemes were suggested for either integration with CO2 capture and utilization processes using flue gas or to produce fly ash for use as a SCM.


Assuntos
Cinza de Carvão , Carvão Mineral , Dióxido de Carbono , Cinza de Carvão/análise , Centrais Elétricas , Enxofre , Dióxido de Enxofre
13.
Ecotoxicol Environ Saf ; 209: 111790, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33316728

RESUMO

AIMS: The objective of the present study was to elucidate the effects of sulfur (S) application on selenium (Se) uptake and seed Se speciation in high-protein soybean (Glycine max L.) grown in different soil types. METHODS: Pot experiments were conducted with soybean plants grown in yellow-brown soil (pH 5.68) and in calcareous alluvial soil (pH 7.87). Sodium selenate (Na2SeO4, 2 mg kg-1) was applied to soil with or without S fertilizer (S, 100 mg kg-1). RESULTS: Soybean grain yield and total biomass in calcareous alluvial soil were both approximately 1.3-fold the levels in yellow-brown soil. Following Se application, seed Se concentration in calcareous alluvial soil was 3.2-fold the concentration in yellow-brown soil, although additional S application reduced the corresponding seed Se concentrations by 55.6% and 38.6%, respectively. Generally, Se application facilitated Se translocation and enrichment in soybean seeds. Organic Se accounted for 92% of seed total Se and Se-methionine (>90%) was always the major Se species. Available Se (soluble and exchangeable fractions) accounted for 50.7% (yellow-brown soil) and 70.1% (calcareous alluvial soil) of soil total Se under Se treatment, while additional S application decreased the corresponding proportion of soluble Se by 12.6% and 14.4%. CONCLUSIONS: The bioavailability of selenate in calcareous alluvial soil was higher than the bioavailability in yellow-brown soil and was more negatively affected by S application. Although S application inhibited Se uptake in soybean plants in both soil types, it did not influence seed Se speciation and Se-methionine was the major Se species.


Assuntos
Selênio/metabolismo , Poluentes do Solo/metabolismo , Soja/fisiologia , Enxofre/análise , Disponibilidade Biológica , Transporte Biológico , Grão Comestível/química , Fertilizantes/análise , Sementes/química , Ácido Selênico , Selenometionina , Solo , Poluentes do Solo/análise
14.
Huan Jing Ke Xue ; 41(8): 3699-3706, 2020 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-33124344

RESUMO

In order to enhance the removal of NO3--N in the ANAMMOX process, an element sulfur-based autotrophic short-cut denitrification (short-cut S0-SADN) was introduced by adding elemental sulfur to an ANAMMOX continuous flow reactor. The effects of different influent NH4+-N/NO2--N ratios on the nitrogen conversion and NO2--N competitive characteristics in the coupled system were investigated at (33±2)℃ and a pH of 7.8-8.2. The results showed that under different influent NH4+-N/NO2--N ratios (1:1.3, 1:1.5, 1:1, and 1:1.1), the average total nitrogen (TN) removal efficiency of the coupled system reached 96.78%, 97.21%, 94.68%, and 97.72%, respectively, which were much higher than the highest TN removal efficiency of the ANAMMOX theory (89%). Among them, the stable operation of deep nitrogen removal of the short-cut S0-SADN coupled with ANAMMOX was successfully achieved with an influent NH4+-N/NO2--N ratio of 1:1 or 1:1.1. Under the optimal influent NH4+-N/NO2--N ratio of 1:1.1, the concentrations of influent NH4+-N and NO2--N were 240 mg·L-1 and 265 mg·L-1, respectively, the TN removal rate reached 1.50 kg·(m3·d)-1, and the TN removal efficiency of ANAMMOX and S0-SADN pathways were stable at (95.68±1.22)% and (2.04±0.77)%, respectively. During the entire operational process, ANAMMOX always occupied an absolute advantage in the competition of substrate NO2--N, and the activity of ANAMMOX bacteria (NH4+-N/VSS) was stable at (0.166±0.008)kg·(kg·d)-1.


Assuntos
Desnitrificação , Nitrogênio , Amônia , Anaerobiose , Reatores Biológicos , Oxirredução , Enxofre
15.
Vestn Oftalmol ; 136(6): 5-14, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33084273

RESUMO

PURPOSE: To analyze the chemical composition of the sclera and trabecular meshwork in patients with primary open-angle glaucoma (POAG) and to assess the impact of corneal-compensated intraocular pressure (IOP) on the chemistry of the drainage area. MATERIAL AND METHODS: Biopsy specimens of the trabecular meshwork (89 specimens) and sclera (41 specimens) obtained from patients with POAG on maximal medical therapy were analyzed to determine the content of certain chemical elements - carbon (C), nitrogen (N), oxygen (O), aluminum (Al), calcium (Ca), chlorine (Cl), potassium (K), magnesium (Mg), sodium (Na), phosphorus (P), silicon (Si) and sulfur (S). The elements were selected based on chemical structure target tissue and sensitivity of the method used for analysis. Visualization was performed using the «EVO LS 10¼ (Zeiss, Germany) scanning electron microscope (SEM), and the chemical composition was studied with the «Oxford-X-MAX-50¼ (Oxford, UK) energy-dispersive spectrometer (EDS). Statistical analysis was performed using the Spearman correlation. RESULTS: The IOP of patients with POAG was found to have positive correlation with the total amount of S, P, and Ca in the trabecular meshwork. The accumulation of sulfur-containing compounds associated with pigment granules in trabecular meshwork's tissue was identified. A correlation was determined between the organic and inorganic (mineral) phosphorus content in the trabeculae, and the IOP values. The organic component of phosphorus was better represented than the mineral component in patients with increased IOP. CONCLUSION: In patients with POAG, an increase in the IOP level causes the amount of S associated with pigment granules and the proportion of organic P to increase in the trabecular meshwork, which should be taken into account in the further search for drug therapy that would potentially affect pathologically altered tissue.


Assuntos
Glaucoma de Ângulo Aberto , Fósforo , Glaucoma de Ângulo Aberto/diagnóstico , Humanos , Pressão Intraocular , Enxofre , Malha Trabecular
16.
Sci Total Environ ; 748: 142445, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33113701

RESUMO

Sulfur autotrophic denitrification utilizes elemental sulfur as the electron donor for nitrate removal from aquatic environments. Organic carbon could stimulate the conversion of sulfur and facilitates the S0-based denitrification process in the mix-trophic. In this study, the co-cultured system of sulfur reducer (Geobacter sulfurreducens) and Thiobacillus denitrificans was used to investigate that how organic carbon could boost the S0-based denitrification. The results showed that the rate of S0-based denitrification was improved with C/N ratio of 0.13 and this improvement continued even after the acetate was exhausted. Sulfur probe test and Raman analysis suggested that reduced sulfur species (Sx2-) were formed with the addition of organic carbon. The Sx2- could recombine with element sulfur and the bioavailability of S0 would be improved, as a result, the rate of S0-based denitrification increased as well. Nitrate reduction rate could further increase with the C/N ratio of 0.88, but it would decrease significantly when the C/N ratio increased to 1.50 as the high concentration of generated S2-. Our results provided explanations that why organic carbon addition would improve the bioavailability of S0 which could further promote the S0-dominant denitrification process.


Assuntos
Thiobacillus , Reatores Biológicos , Carbono , Desnitrificação , Geobacter , Nitratos , Nitrogênio , Enxofre
17.
J Environ Qual ; 49(3): 762-768, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-33016392

RESUMO

Sulfur (S) and sulfate (SO4 2- ) in fine particulate matter (PM2.5 ) are monitored by the Interagency Monitoring of Protected Visual Environments (IMPROVE) network at remote and rural sites across the United States. Within the IMPROVE network, S is determined from X-ray fluorescence (XRF) spectroscopy from a Teflon filter, and SO4 2- is determined via ion chromatography (IC) from a nylon filter. Differences in S and SO4 2- estimates may indicate the presence of organosulfur (OS) species or biases between sampling and analytical methods. To reduce potential biases, an inductively coupled plasma-optical emission spectroscopy (ICP-OES) method was developed to allow for analysis of SO4 2- and S from a single filter extract. Sulfur (ICP-OES) and SO4 2- (IC) estimates from 2016 IMPROVE filters correlated strongly, suggesting that, on average, ICP-OES accurately estimated S. However, observed differences between slopes suggested the presence of water-soluble OS species, especially during summer. Organosulfur species are important indicators of secondary organic aerosols formed through reactions of biogenic and anthropogenic pollutants and can be quantified through laboratory techniques such as reverse-phase liquid chromatography (RPLC) or hydrophilic liquid interaction chromatography (HILIC) coupled to electrospray ionization-high-resolution tandem mass spectrometry (RPLC/ESI-HR-MS/MS and HILIC/ESI-HR-MS/MS, respectively), and field techniques using Aerodyne aerosol mass spectrometry (AMS). However, these methods are costly and introduce relatively large uncertainties when scaled for large networks such as IMPROVE. The method described in this report provides an inexpensive complement to XRF, which measures total S (insoluble and water-soluble S) to estimate water-soluble S and OS concentrations in PM.


Assuntos
Nylons , Espectrometria de Massas em Tandem , Aerossóis , Análise Espectral , Enxofre , Estados Unidos
18.
Environ Pollut ; 267: 115444, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32866874

RESUMO

The high frequency of acid rain in southern China has captured public and official concern since 1980s. Subsequently, gas emission reduction measures have been implemented to improve the air quality. Variations in SO2 emission intensities can influence the sulfur and oxygen isotopic compositions of sulfate in rainwater, since atmospheric sulfate is mainly formed via the oxidation of sulfur gases from natural and anthropogenic sources. To evaluate the impacts of emission reduction measures on atmospheric sulfate, the seasonal and long-term trends in stable isotopic compositions of sulfate in rainwater in Guizhou province, southwestern China have been investigated based on rainwater samples collected from June 2016 to June 2018 and literature investigation (2000-2010).The results reveal that coal combustion remains a major contributor to sulfate in rainwater, although its SO2 emission has significantly decreased over the past two decades. The δ34Ssulfate and δ18Osulfate values in rainwater are negatively correlated and have significant seasonal changes. The seasonality in δ34Ssulfate has been interpreted as due to the changes in contributions of dimethyl sulfide and coal combustion, while the seasonal pattern of δ18Osulfate is consistent with that of δ18Owater values, indicating sulfate in rainwater is mainly formed by heterogeneous oxidation of SO2. Combined with the data from previous studies (Xiao and Liu, 2002; Liu, 2007; Xiao et al., 2009; Xiao et al., 2014), we found that the volume weighted mean δ34S values of sulfate in rainwater in Guizhou province show a marked increase between 2001 and 2018, indicating that the 34S-depleted SO2 emission from coal combustion has declined during this period. Furthermore, the synchronous changes in δ34S values, sulfate concentration and pH values of rainwater suggest that the frequency of acid rain in Guizhou province has dropped over the past two decades, which is likely to result from the emission reduction measures taken in Guizhou province.


Assuntos
Chuva Ácida , Chuva Ácida/análise , China , Monitoramento Ambiental , Isótopos de Oxigênio/análise , Enxofre , Isótopos de Enxofre/análise
19.
J Environ Manage ; 275: 111301, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32866922

RESUMO

The comparative performance of an inverse fluidized bed reactor (IFBR) having high density polyethylene beads as carrier materials for biofilm formation and a continuous stirred tank reactor (CSTR), both maintaining autotrophic denitrification using biogenic sulphur (ADBIOS) in the absence and presence of nickel (Ni2+), was studied. The reactors were compared in terms of NO3--N and NO2--N removal and SO42--S production throughout the study. A simulated wastewater with an inlet NO3--N concentration of 225 mg/L and a decreasing concentration of biogenic sulphur (bio-S) from 1.5 to 0.375 g/L was used. Both reactors were operated at a hydraulic retention time (HRT) of 48 h for 140 days and at an HRT of 42 h for the following 68 days. A more efficient ADBIOS was observed in the CSTR than IFBR throughout the study due to a better mixing of the feed wastewater in the bulk liquid and a higher availability of bio-S to the suspended cells. The NO3--N removal efficiency in the IFBR decreased by approximately 41% when the feed bio-S was reduced to 0.375 g/L, while it remained unaffected in the CSTR. Conversely, the presence of Ni2+ did not significantly affect NO3--N removal in both reactors even at a feed Ni2+ concentration of 120 mg/L. The highest NO3--N removal rates achieved were 86 and 108 mg NO3--N/(L·day) in the IFBR and CSTR, respectively, in the presence of 120 mg/L of feed Ni2+ at an HRT of 42 h. Batch studies conducted with acclimatized biomass showed that the continuous-flow operation mode in both reactors played a major role in helping the autotrophic denitrifiers to tolerate Ni2+ toxicity.


Assuntos
Desnitrificação , Níquel , Processos Autotróficos , Reatores Biológicos , Enxofre
20.
Environ Sci Pollut Res Int ; 27(33): 42182-42188, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32888153

RESUMO

In this study, we report for the first time a novel type of sorbent that can be used for mercury adsorption from the air-based off-gasses-vermiculite impregnated with alkali polysulfides and thiosulfates. In contrast to other sorbents, vermiculite exhibits superior thermal stability in air and low adsorption capacity for organic vapors. This allows for a more favorable design of the soil remediation unit-direct coupling of thermal desorber with catalytic oxidizer using air as a carrier gas. In the bench-scale test at 180 °C, the sulfur/vermiculite sorbent exhibited significantly higher efficiency for the adsorption of mercury vapor from the off-gasses than the commercial sulfur/activated carbon sorbent at its highest operating temperature (120 °C). The average mercury concentration in the adsorber off-gas decreased from 1.634 mg/m3 for the sulfur/activated carbon to 0.008 mg/m3 achieved with impregnated vermiculite. The total concentration of organic compounds in the soil after thermal desorption was below the detection limit of the employed analytical method.


Assuntos
Mercúrio , Enxofre , Adsorção , Silicatos de Alumínio , Gases
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