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1.
Environ Sci Technol ; 57(32): 11977-11987, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37526086

RESUMO

While carbon dots (CDs) have the potential to support the agricultural revolution, it remains obscure about their environmental fate and bioavailability by plants. Fungal laccase-mediated biotransformation of carbon nanomaterials has received little attention despite its known capacity to eliminate recalcitrant contaminants. Herein, we presented the initial investigation into the transformation of CDs by fungal laccase. The degradation rates of CDs were determined to be first-order in both substrate and enzyme. Computational docking studies showed that CDs preferentially bonded to the pocket of laccase on the basal plane rather than the edge through hydrogen bonds and hydrophobic interactions. Electrospray ionization-Fourier transform-ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS) and other characterizations revealed that the phenolic/amino lignins and tannins portions in CDs are susceptible to laccase transformation, resulting in graphitic structure damage and smaller-sized fragments. By using the 13C stable isotope labeling technique, we quantified the uptake and translocation of 13C-CDs by mung bean plants. 13C-CDs (10 mg L-1) accumulated in the root, stem, and leaf were estimated to be 291, 239, and 152 µg g-1 at day 5. We also evidenced that laccase treatment alters the particle size and surface chemistry of CDs, which could facilitate the uptake of CDs by plants and reduce their nanotoxicity to plants.


Assuntos
Carbono , Lacase , Lacase/química , Lacase/metabolismo , Biodegradação Ambiental , Espectrometria de Massas , Biotransformação , Trametes/metabolismo
2.
J Environ Sci (China) ; 124: 268-280, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36182136

RESUMO

Zr-based metal-organic frameworks (MOFs) have been developed in recent years to treat heavy metals, e.g. hexavalent chromium Cr6+ pollution, which damages the surrounding ecosystem and threaten human health. This kind of MOF is stable and convenient to prepare, but has the disadvantage of low adsorption capacity, limiting its wide application. To this end, a novel formic acid and amino modified MOFs were prepared, referred to as Form-UiO-66-NH2. Due to the modification of formic acid, its specific surface area, pore size, and crystal size were effectively expanded, and the adsorption capacity of Cr6+ was significantly enhanced. Under optimal conditions, Form-UiO-66-NH2 exhibited an excellent adsorption capacity (338.98 mg/g), ∼10 times higher than that reported for unmodified Zr-based MOFs and most other adsorbents. An in-depth study on the photoelectronic properties and pH confirmed that the adsorption mechanism of Form-UiO-66-NH2 to Cr6+ was electrostatic adsorption. After modification, the improvement of Cr6+ adsorption capacity by Form-UiO-66-NH2 was attributed to the expansion of its specific surface area and the increase in its surface charge. The present study revealed an important finding that Form-UiO-66-NH2 elucidated selective adsorption to Cr6+ in mixed wastewater containing toxic heavy metal ions and common nonmetallic water quality factors. This research provided a new acid and amino functionalization perspective for improving the adsorption capacity of Zr-based MOF adsorbents while simultaneously demonstrating their pertinence to target contaminant adsorption.


Assuntos
Estruturas Metalorgânicas , Metais Pesados , Poluentes Químicos da Água , Purificação da Água , Adsorção , Ecossistema , Formiatos , Humanos , Íons , Estruturas Metalorgânicas/química , Ácidos Ftálicos , Águas Residuárias , Poluentes Químicos da Água/análise
3.
Environ Sci Technol ; 56(8): 4980-4987, 2022 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-35349262

RESUMO

Photoelectrocatalysis (PEC) is an efficient way to address various pollutants. Surface-adsorbed atomic hydrogen (H*) and hydroxyl radicals (•OH) play a key role in the PEC process. However, the instability of H* and low production of •OH considerably limit the PEC efficiency. In this study, we noted that incorporating oxygen atoms could regulate the behavior of H* by creating a locally favorable electron-rich state of S atoms in the SnS2 catalyst. The finely modulated H* led to a 12-fold decrease in the overpotential of H2O2 generation (H*-OOH*-H2O2-•OH) by decreasing the activation energy barrier of OOH* (rate-determining step). Considering density functional theory calculations, an H*-•OH redox pair suitable for a wide pH range (3-11) was successfully constructed based on the photocathode. The optimal SnS1.85O0.15 AL@TNA photocathode exhibited a ∼90% reduction in Cr(VI) in 10 min and ∼70% TOC removal of 4-nitrophenol, nearly 2- and 3-fold higher than that without oxygen incorporation. Electron spin resonance spectrometry and radical quenching experiments verified that H* and the derived •OH via 1-electron and 3-electron reduction were the main active species. Operando Raman spectroscopy confirmed that the stable SnO2 phase helped constantly activate the production of H* and •OH.

4.
Environ Sci Technol ; 56(24): 17663-17673, 2022 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-36456188

RESUMO

Understanding how nanomaterials interact with cell membranes has important implications for ecotoxicology and human health. Here, we investigated the interactions between graphitic carbon nitride (g-C3N4, CN) and red blood cells, a plausible contact target for nanoparticles when they enter the bloodstream. Through a hemolysis assay, the cytotoxicity of CN derived from different precursors was quantitatively assessed, which is highly related to the surface area of CN. Reactive oxygen species (ROS) generation and lipid peroxidation detection confirmed that CN causes rapid cell membrane rupture by a physical interaction mechanism rather than ROS-related chemical oxidation. Dye leakage assay and theoretical simulation indicated that the less-layered CN is prone to folding inward to wrap and extract lipid molecules from cell membranes. The electron-rich inherent pores of CN play a dominant role in capturing the headgroups of phospholipids, whereas the hydrophobic interaction is critical for the anchoring of lipid tails. Our further experimental evidence demonstrated that the destructive extraction of phospholipids from cell membranes by CN occurs primarily in the outer leaflet, and phosphatidylcholine is the most easily extracted lipid. Moreover, the formation of protein corona on CN was found to decrease the nonspecific interactions but increase steric repulsion, thus mitigating CN cytotoxicity. Overall, our data provide a molecular basis for CN's cytotoxicity.


Assuntos
Bicamadas Lipídicas , Fosfolipídeos , Humanos , Bicamadas Lipídicas/análise , Fosfolipídeos/análise , Espécies Reativas de Oxigênio/análise , Membrana Celular
5.
Langmuir ; 36(30): 9005-9013, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32614590

RESUMO

The low separation rate of electron-hole pairs in single-component photocatalysts severely limits their applications for wastewater treatment. For this study, SnO2/BiOCOOH photocatalysts in flower-like microspheres were controllably synthesized via a one-step hydrothermal method and were characterized by various advanced techniques. These SnO2/BiOCOOH nanocomposites demonstrated excellent photocatalytic activities for the degradation of rhodamine B (RhB), titan yellow, and levofloxacin hydrochloride (LVF). Specifically, 98.5% of RhB, 80% of titan yellow, and 85% of LVF were degraded under 5 W LED (λ = 365 nm) light irradiation within 30, 40, and 60 min, respectively. Radical trapping experiments and electron spin resonance results indicated that h+ was the dominant active radical, whereas ·O2- and ·OH played an auxiliary role in the photocatalytic system. Subsequently, a potential photocatalytic mechanism was proposed based on the experimental results.

6.
Ecotoxicol Environ Saf ; 198: 110676, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32361496

RESUMO

Triclosan (TCS), an extensively used broad-spectrum antimicrobial agent, has raised significant environmental concerns regarding its widespread occurrence in waters. In this study, the removal of TCS in aqueous solution via peroxymonosulfate (PMS) activated by an extremely low-level Co2+ (0.02 µM) was systematically investigated. During preliminary test, TCS (10 µM) was totally degraded in 30 min by using 0.1 µM Co2+ and 40 µM PMS at pH 7.0 with a degradation rate constant of 0.1219 min-1. A first-order apparent degradation rate of TCS was found with respect to the PMS concentrations. At extremely low dosage of Co2+ (0.02 µM), the presence of NO3-, HCO3-, PLFA, and SRHA within test concentrations significantly inhibited TCS removal, while a dual effect of Cl- on the degradation rate of TCS was observed. The quenching experiments verified that SO4- was the dominant reactive oxygen species (ROS) rather than OH. Six major intermediates were identified using TOF-LC-MS, based on which we proposed three associated reaction pathways including hydroxylation, ether bond breakage, and dechlorination. Toxicity predictions by ECOSAR software exhibited aquatic toxicity reduction of TCS after Co2+/PMS treatment. We outlook these findings to advance the feasibility of organic contaminants removal via Co2+/PMS system with Co2+ at extremely low levels.


Assuntos
Cobalto/análise , Peróxidos/análise , Triclosan/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Cinética , Triclosan/química , Água
7.
Ecotoxicol Environ Saf ; 193: 110368, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32114245

RESUMO

Emerging POPs have received increasing attention due to their potential persistence and toxicity, but thus far the report regarding the occurrence and distribution of these POPs in PM2.5 is limited. In this study, an extremely sensitive and reliable method, using ultrasonic solvent extraction and silica gel purification followed by gas chromatography coupled with electron ionization triple quadrupole mass spectrometry, was developed and used for the trace analysis of hexachlorobutadiene (HCBD), pentachloroanisole (PCA) and its analogs chlorobenzenes (CBs) in PM2.5 from Taiyuan within a whole year. The limits of detection and limits of quantitation of analytes were 1.14 × 10-4‒2.74 × 10-4 pg m-3 and 3.80 × 10-4‒9.14 × 10-4 pg m-3. HCBD and PCA were detected at the mean concentrations of 3.69 and 1.84 pg m-3 in PM2.5, which is reported for the first time. Based on the results of statistical analysis, HCBD may come from the unintentional emission of manufacture or incineration of chlorinate-contained products but not coal combustion, while O3-induced photoreaction was the potential source of PCA in PM2.5. The temporal distributions of CBs in PM2.5 were closely related to coal-driven or agricultural activities. Accordingly, our study reveals the contamination profiles of emerging POPs in PM2.5 from Taiyuan.


Assuntos
Poluentes Atmosféricos/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Material Particulado/química , Anisóis/análise , Butadienos/análise , Clorobenzenos/análise , Carvão Mineral , Incineração , Espectrometria de Massas em Tandem/métodos
8.
Ecotoxicol Environ Saf ; 201: 110827, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32535366

RESUMO

Numerous experimental and epidemiological studies have demonstrated that exposure to PM2.5 may result in pathogenesis of several major cardiovascular diseases (CVDs), which can be attributed to the combined adverse effects induced by the complicated components of PM2.5. Organic materials, which are major components of PM2.5, contain thousands of chemicals, and most of them are environmental hazards. However, the contamination profile and contribution to overall toxicity of PM2.5-bound organic components (OCs) have not been thoroughly evaluated yet. Herein, we aim to provide an overview of the literature on PM2.5-bound hydrophobic OCs, with an emphasis on the chemical identity and reported impairments on the cardiovascular system, including the potential exposure routes and mechanisms. We first provide an update on the worldwide mass concentration and composition data of PM2.5, and then, review the contamination profile of PM2.5-bound hydrophobic OCs, including constitution, concentration, distribution, formation, source, and identification. In particular, the link between exposure to PM2.5-bound hydrophobic OCs and CVDs and its possible underlying mechanisms are discussed to evaluate the possible risks of PM2.5-bound hydrophobic OCs on the cardiovascular system and to provide suggestions for future studies.


Assuntos
Poluentes Atmosféricos/toxicidade , Doenças Cardiovasculares/induzido quimicamente , Sistema Cardiovascular/efeitos dos fármacos , Monitoramento Ambiental/métodos , Compostos Orgânicos/toxicidade , Material Particulado/toxicidade , Poluentes Atmosféricos/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Compostos Orgânicos/química , Material Particulado/química
9.
Ecotoxicol Environ Saf ; 183: 109555, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31419699

RESUMO

In this study, we investigated the transformation of atenolol (ATL) by the naturally occurring laccase from Trametes versicolor in aqueous solution. Removal efficiency of ATL via laccase-catalyzed reaction in the presence of various laccase mediators was examined, and found that only the mediator 2, 2, 6, 6-tetramethyl-1-piperidinyloxy (TEMPO) was able to greatly promote ATL transformation. The influences of TEMPO concentration, laccase dosage, as well as solution pH and temperature on ATL transformation efficiency were tested. As TEMPO concentrations was increased from 0 to 2000 µM, ATL transformation efficiency first increased and then decreased, and the optimal TEMPO concentration was determined as 500 µM. ATL transformation efficiency was gradually increased with increasing laccase dosage. ATL transformation was highly pH-dependent with an optimum pH of 7.0, and it was almost constant over a temperature range of 25-50 °C. Humic acid inhibited ATL transformation through competition reaction with laccase. The presence of anions HCO3- and CO32- reduced ATL transformation due to both anions enhanced solution pHs, while Cl-, SO42-, and NO3- at 10 mM showed no obvious influence. The main transformation products were identified, and the potential transformation pathways were proposed. After enzymatic treatment, the toxicity of ATL and TEMPO mixtures was greatly reduced. The results of this study might present an alternative clean strategy for the remediation of ATL contaminated water matrix.


Assuntos
Atenolol/análise , Óxidos N-Cíclicos/química , Lacase/metabolismo , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Atenolol/metabolismo , Catálise , Substâncias Húmicas/análise , Oxirredução , Temperatura , Trametes/enzimologia , Poluentes Químicos da Água/metabolismo
10.
Ecotoxicol Environ Saf ; 168: 378-387, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30396134

RESUMO

A growing number of epidemiological surveys show that PM2.5 is an important promoter for the cardiovascular dysfunction induced by atmospheric pollution. PM2.5 is a complex mixture of solid and liquid airborne particles and its components determine the health risk of PM2.5to a great extent. However, the individual cardiotoxicities of different PM2.5 fractions are still unclear, especially in the cellular level. Here we used the neonatal rat cardiomyocytes (NRCMs) to evaluate the cardiac toxicity of PM2.5 exposure. The cytotoxicities of Total-PM2.5, water soluble components of PM2.5 (WS-PM2.5) and water insoluble components of PM2.5 (WIS-PM2.5), which include the cell viability, cell membrane damage, reactive oxygen species (ROS) generation, were examined with NRCMs in vitro. The results indicated that Total-PM2.5 or WIS-PM2.5 exposure significantly decreased the cell viability, induced the cell membrane damage and increased the ROS level in NRCMs at concentrations above 50 µg/mL. However, WS-PM2.5 exposure could induce the cytotoxicity on NRCMs until the concentration of WS-PM2.5 was raised to a higher concentration (75 µg/mL). Furthermore, the DNA damage was detected in NRCMs after 48 h of exposure with Total-PM2.5, WS-PM2.5 or WIS-PM2.5 (75 µg/mL) and the adverse effects on mitochondrial function and action potentials of NRCMs were detected only both in the Total-PM2.5 and WIS-PM2.5 treatment group. In summary, our project not only estimates the risk of PM2.5 on cardiac cells but also reveal that Total-PM2.5 and WIS-PM2.5 exposure were predominantly associated with the functional cardiotoxicities in NRCMs.


Assuntos
Cardiotoxinas/toxicidade , Miócitos Cardíacos/efeitos dos fármacos , Material Particulado/toxicidade , Animais , Animais Recém-Nascidos , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Dano ao DNA/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Miócitos Cardíacos/metabolismo , Ratos , Espécies Reativas de Oxigênio/metabolismo
11.
J Environ Manage ; 207: 219-229, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29179111

RESUMO

China is the largest freshwater aquaculture producer and antibiotics consumer in the world, and rivers in China are generally polluted by antibiotics. However, there is little information available regarding the linkage of antibiotics in aquaculture and the aquatic environment. Therefore, this study investigated the fate of antibiotics in several open water culture-based freshwater aquafarms, including integrated livestock/fish systems and non-integrated fish ponds, and explored the contamination profiles of antibiotics in the Beijiang River. Then the study tried to clarify the two-way interaction of antibiotics in aquaculture and the environment. The results showed that, when compared with the effluent from livestock farms and wastewater treatment plants, the contribution of antibiotics from non-integrated fish pond water without livestock sewage input was limited, while that of effluent from the integrated livestock/fish system was quite high. The total concentrations of antibiotics detected in the aquafarm source water were similar to those in the upper river water and generally higher than those in the corresponding fish pond water, implying that the occurrence of antibiotics in intensive aquafarms can mainly be attributed to the antibiotic residues in nearby river water. Overall, the results underscore the need to develop a sewage infrastructure for the treatment of effluent from integrated livestock/fish aquafarms, and suggest that open water culture-based fish farms should be located far from seriously contaminated sections of rivers.


Assuntos
Antibacterianos , Monitoramento Ambiental , Poluentes Químicos da Água , Animais , China , Rios
12.
Water Sci Technol ; 75(5-6): 1342-1350, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28333050

RESUMO

The potential reaction of diclofenac (DCF) with ferrate(VI) and influences of coexisting surfactants have not been investigated in depth, and are the focus of this study. The results demonstrated that DCF reacted effectively and rapidly with Fe(VI) and approximately 75% of DCF (0.03 mM) was removed by excess Fe(VI) (0.45 mM) within 10 min. All of the reactions followed pseudo first-order kinetics with respect to DCF and Fe(VI), where the apparent second-order rate constant (kapp) was 5.07 M-1 s-1 at pH 9.0. Furthermore, the degradation efficiencies of DCF were clearly dependent on the concentrations of dissolved organic matter additives in the substrate solution. Primarily, inhibitory effects were observed with the samples that contained anionic (sodium dodecyl-benzene sulfonate, SDBS) or non-ionic (Tween-80) surfactants, which have been attributed to the side reactions between Fe(VI) and surfactants, which led to a reduction in the available oxidant for DCF destruction. Furthermore, the addition of a cationic surfactant (cetyltrimethyl ammonium bromide, CTAB) and humic acid (HA) conveyed significantly promotional effects on the DCF-Fe(VI) reaction. The rate enhancement effect for CTAB might be due to micellar surface catalysis, through the Coulomb attraction between the reactants and positively charged surfactants, while the catalytic action for HA resulted from the additional oxidation of Fe(V)/Fe(IV) in the presence of HA. The results provided the basic knowledge required to understand the environmental relevance of DCF oxidation via Fe(VI) in the presence of surfactant additives.


Assuntos
Diclofenaco/química , Ferro/química , Tensoativos/química , Poluentes Químicos da Água/análise , Benzenossulfonatos/química , Catálise , Cetrimônio , Compostos de Cetrimônio/química , Substâncias Húmicas/análise , Cinética , Oxirredução , Polissorbatos/química
13.
Water Sci Technol ; 73(4): 807-17, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26901723

RESUMO

An innovative integrated multistage bioreactor (IMBR) system, which was augmented with three predominant bacterial strains (Lactobacillus paracasei CL1107, Pichia jadinii CL1705, and Serratia marcescens CL1502) isolated from marine sediments, was developed to treat real tannery wastewater without performing physicochemical pretreatment, with the potential to reduce the generation of waste sludge and odors. The performance of the IMBR treatment system, with and without the inclusion of the predominant bacterial strains, was compared. The results indicated that the performance of the IMBR system without bioaugmentation by the predominant bacterial strains was poor. However, when in the presence of the predominant bacterial strains, the IMBR system exhibited high removal efficiencies of chemical oxygen demand (COD) (97%), NH4(+)-N (97.7%), and total nitrogen (TN) (90%). In addition, the system had the capacity for the simultaneous removal of organics and nitrogen, heterotrophic nitrification and denitrification being carried out concurrently, thereby avoiding the strong inhibition of high concentrations of COD on nitrification. The system possessed excellent adaptability and ability to resist influent loading fluctuations, and had a good alkalinity balance such that it could achieve a high NH4(+)-N, and TN removal efficiency without a supplement of external alkalinity. In addition, an empirical performance modeling of the IMBR system was analyzed.


Assuntos
Bactérias/metabolismo , Reatores Biológicos/microbiologia , Sedimentos Geológicos/microbiologia , Águas Residuárias/microbiologia , Purificação da Água/métodos , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Desnitrificação , Nitrificação , Esgotos/análise , Esgotos/microbiologia , Águas Residuárias/análise , Purificação da Água/instrumentação
14.
Artigo em Inglês | MEDLINE | ID: mdl-27088814

RESUMO

The present study employed a Mn-Cu/Al2O3 heterogeneous catalytic ozonation process for tertiary treatment of actual tannery wastewater, focusing on its feasibility in that application. The primary factors affecting the removal efficiency of organic pollutants were investigated, including catalyst dosage, ozone dosage, and initial pH value. The experimental results showed that the addition of a Mn-Cu/Al2O3 catalyst improved the removal efficiency of chemical oxygen demand (COD) during ozonation, which initiated a 29.3% increase for COD removal, compared to ozonation alone after 60 min. The optimum pH, catalyst dosage, and ozone dosage were determined to be 7.0, 2.0 g/L, and 0.3 g/h, respectively. Under these conditions, following 60 min of reaction, the COD removal efficiency and the concentration in effluent were 88%, and 17 mg/L, respectively. In addition, the presence of tert-butanol (a well known hydroxyl radical scavenger) strongly inhibited COD removal via Mn-Cu/Al2O3 catalytic ozonation, indicating that the Mn-Cu/Al2O3 catalytic ozonation process follows a hydroxyl radical (OH·) reaction mechanism. The Mn-Cu/Al2O3 catalyst exhibited good stability and reusability. Finally, the kinetic analysis revealed that the apparent reaction rate constant of COD removal with the Mn-Cu/Al2O3 catalytic ozonation system (0.0328 min(-1)) was 2.3 times that of an ozonation system alone (0.0141 min(-1)). These results demonstrated that the catalytic ozonation using Mn-Cu/Al2O3 is an effective and promising process for tertiary treatment of tannery effluent in biological systems.


Assuntos
Resíduos Industriais , Ozônio/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Catálise , Humanos , Águas Residuárias/química
15.
Appl Microbiol Biotechnol ; 99(17): 7295-305, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25957151

RESUMO

A novel bioelectrochemical system (BES) operated with polarity reversion was explored for simultaneous anaerobic/aerobic treatment of azo dye and production of bioelectricity under extremely low buffer. The Congo red was first decolorized in anode, with completed color removal in 35 h. The resultant decolorization intermediates were then mineralized after the anode reversed to aerobic biocathode, evidenced by 55 % chemical oxygen demand (COD) removal in 200 h. The mineralization efficiency was further increased to 70 % when the period of the half-cycle was prolonged to 375 h. Meanwhile, the BES produced a continuous stable positive/negative alternate voltage output under 5 mM phosphate buffer because of the self-neutralization of the accumulated protons and hydroxyl ions in electrolyte. The electrode performance was significantly improved, which was indicated by alleviated electrode polarization, due to in situ use of accumulated protons and hydroxyl ions and enhanced electron transfer in the presence of Congo red and its degradation intermediates, which resulted in 1.05-fold increases in maximum power density (67.5 vs. 32.9 mW/m(2)). An analysis of the microbial diversity in the biofilm revealed that the biofilm was dominated by facultative bacteria with functional roles in contaminant degradation and electricity generation.


Assuntos
Compostos Azo/metabolismo , Bactérias/crescimento & desenvolvimento , Fontes de Energia Bioelétrica , Eletricidade , Aerobiose , Anaerobiose , Bactérias/classificação , Biodiversidade , Biofilmes/crescimento & desenvolvimento , Análise da Demanda Biológica de Oxigênio , Vermelho Congo/metabolismo , Eletrodos/microbiologia , Fatores de Tempo
16.
J Environ Manage ; 157: 297-302, 2015 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-25919416

RESUMO

Lactobacillus paracase CL1107 capable of removing toxic chromium (Cr(VI)) and Acid Black (ATT) azo dye simultaneously was isolated from deep sea sediment of the North Atlantic. CL1107 exhibited appreciable dye-Cr(VI) bioremoval ability in the pH range from 5 to 7, temperature 25-35 °C and NaCl 0-6% under aerobic conditions. The maximum removal values of Cr(VI) (95.8%) and dye (92.3%) were obtained in the media including only Cr(VI) or dye at initial concentration of 100 mg/L. In the experiments for the simultaneous treatment of both pollutants, the reduction of Cr(VI) and dye was 58.5% and 51.9%, respectively. The azo dye and Cr(VI) reductive activities in strain CL1107 were located in the cell free extract and cell debris, respectively. The mechanisms of azo dye and Cr(VI) reduction were found to be enzyme-mediated. In the treatment of saline tannery wastewater, decolourization of about 76% and 63% Cr(VI) reduction of were achieved. Furthermore, Azo dyes, Cr(VI) and wastewater showed reduced toxicity toward Artemia salina after treatment. These results demonstrate the potential of CL1107 in bioremediation of dye or/and Cr(VI) contamination in salt environments.


Assuntos
Cromatos/química , Corantes/química , Lactobacillus/metabolismo , Poluentes Químicos da Água/química , Biodegradação Ambiental , Humanos , Oxirredução , Água do Mar , Purificação da Água/métodos
17.
J Struct Biol ; 185(3): 366-74, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24468289

RESUMO

The STE20 kinases MST1 and MST2 are key players in mammalian Hippo pathway. The SARAH domains of MST1/2 act as a platform to mediate homodimerization and hetero-interaction with a range of adaptors including RASSFs and Salvador, which also possess SARAH domains. Here, we determined the crystal structure of human MST2 SARAH domain, which forms an antiparallel homodimeric coiled coil. Structural comparison indicates that SARAH domains of different proteins may utilize a shared dimerization module to form homodimer or heterodimer. Structure-guided mutational study identified specific interface residues critical for MST2 homodimerization. MST2 mutations disrupting its homodimerization also impaired its hetero-interaction with RAPL (also named RASSF5 and NORE1), which is mediated by their SARAH domains. Further biochemical and cellular assays indicated that SARAH domain-mediated homodimerization and hetero-interaction with RAPL are required for full activation of MST2 and therefore apoptotic functions in T cells.


Assuntos
Proteínas Monoméricas de Ligação ao GTP/química , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Apoptose/genética , Apoptose/fisiologia , Proteínas Reguladoras de Apoptose , Linhagem Celular , Citometria de Fluxo , Humanos , Imunoprecipitação , Proteínas Monoméricas de Ligação ao GTP/genética , Mutação/genética , Ligação Proteica/genética , Ligação Proteica/fisiologia , Proteínas Serina-Treonina Quinases/genética , Estrutura Terciária de Proteína , Serina-Treonina Quinase 3
18.
J Colloid Interface Sci ; 675: 926-934, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-39002242

RESUMO

Mixed-dimensional van der Waals heterojunctions (MD-vdWhs), known for exceptional electron transfer and charge separation capabilities, remain underexplored in photocatalysis. In this study, we leveraged the synergistic effect of intermolecular π â†’ π* and D-π-A dual channels to fabricate novel MD-vdWhs. Owing to the synergistic effect, it exhibits superior electron transfer and delocalization ability, thereby enhancing its photocatalytic performance. The Optimal photocatalyst can degrade 98.78 % of 20 mg/L tetracycline (TC) within 15 min. Additionally, we introduced a novel proof strategy for investigating the photoelectron transfer path, creatively demonstrating the synergistic dual channels effect, which can be attributed to the carbonyl density and light-excitation degree. Notably, even under low-power light sources, it achieved complete inactivation of Escherichia coli within just 7 mins, far surpassing current cutting-edge research. This theoretical framework holds promise for broader applications within related studies.

19.
J Hazard Mater ; 478: 135582, 2024 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-39173391

RESUMO

Advanced oxidation processes are a desirable technology for treatment of contaminants of emerging concern. Nevertheless, conventional advanced oxidation of organophosphorus compounds releases inorganic phosphate, posing downstream concerns related to eutrophication. For this reason, we evaluated the ultraviolet light-activated calcium peroxide (UV/CaO2) system for effective treatment of organophosphorus compounds and concurrent capture of the mineralization products, phosphate. The degradation mechanisms, reaction kinetics, and mineralizations were assessed to determine the overall efficiency and performance of the UV/CaO2 process. Knowledge gaps related to photocatalysis in the UV/CaO2 system were not only addressed, but also leveraged to identify unique advantages for removal of organophosphorus compounds and their degradation products. Experimental results confirmed that the UV/CaO2 system effectively mineralized organophosphorus compounds and recovered inorganic phosphate; additionally, collaborative carbon fixation performance of the system reveals the potential of carbon utilization. These outcomes were facilitated by the alkaline environment generated by CaO2. The recovered solids contained most of the phosphorus and carbon from the parent compounds. Ultimately, these findings provide transformative, new insights into the development and application of advanced oxidation processes that prevent downstream concerns related to mineralization products, especially inorganic phosphorus and carbon.

20.
Environ Pollut ; 359: 124579, 2024 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-39032547

RESUMO

To improve the water environment quality, the development of an effective photocatalyst for pollutant removal was considered a promising strategy. The aim of the development of a novel photocatalyst PNC is pursued by modifying copper-phenylacetylide (PhC2Cu) with nitrogen-doped carbon quantum dots (N-CDs). Leading to a remarkable improvement in its light absorption capability, electron transfer efficiency and photoelectrochemical properties. Importantly, PNC possesses the characteristic of straightforward synthesis and demonstrates remarkable performance in the photodegradation of 99.87% sulfamethoxazole (SMX) within just 15 min, with a 3.95-fold increase in the photocatalytic rate. Analysis of the active substances revealed that 1O2, O2·-, and h+ are the generated active species by PNC. Active sites and degradation pathways of SMX were explored through density functional theory (DFT) calculations and intermediate analysis. Key evidence regarding the direction of electron transfer within the system was obtained through in-situ irradiated X-ray (ISI-XPS) techniques. This study deepened our understanding of the electron transfer characteristics of phenylacetylene copper and provided new insights for the modification of photocatalysts.


Assuntos
Carbono , Cobre , Pontos Quânticos , Poluentes Químicos da Água , Purificação da Água , Carbono/química , Cobre/química , Pontos Quânticos/química , Cinética , Poluentes Químicos da Água/química , Transporte de Elétrons , Purificação da Água/métodos , Nitrogênio/química , Fotólise , Catálise , Sulfametoxazol/química , Técnicas Eletroquímicas/métodos , Processos Fotoquímicos
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