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1.
Adv Mater ; : e2404278, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38743014

RESUMO

Atom-site catalysts, especially for graphitic carbon nitride-based catalysts, represents one of the most promising candidates in catalysis membrane for water decontamination. However, unravelling the intricate relationships between synthesis-structure-properties remains a great challenge. This study addressed the impacts of coordination environment and structure units of metal central sites based on Mantel test, correlation analysis and evolution of metal central sites. An optimized unconventional oxygen doping cooperated with Co-N-Fe dual-sites (OCN Co/Fe) exhibited synergistic mechanism for efficient peroxymonosulfate activation, which benefited from a significant increase in charge density at the active sites and the regulation in the natural population of orbitals, leading to selective generation of SO4 •-. Building upon these findings, the OCN-Co/Fe/PVDF composite membrane demonstrated a 33 min-1 ciprofloxacin (CIP) rejection efficiency and maintained over 96% CIP removal efficiency (over 24 h) with an average permeance of 130.95 L m-2 h-1. Our work offers a fundamental guide for elucidating the definitive origin of catalytic performance in advance oxidation process (AOPs) to facilitate the rational design of separation catalysis membrane with improved performance and enhanced stability. This article is protected by copyright. All rights reserved.

2.
J Hazard Mater ; 471: 134351, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38653136

RESUMO

Macrophyte rhizospheric dissolved organic matter (ROM) served as widespread abiotic components in aquatic ecosystems, and its effects on antibiotic residues and antibiotic resistance genes (ARGs) could not be ignored. However, specific influencing mechanisms for ROM on the fate of antibiotic residues and expression of ARGs still remained unclear. Herein, laboratory hydroponic experiments for water lettuce (Pistia stratiotes) were carried out to explore mutual interactions among ROM, sulfamethoxazole (SMX), bacterial community, and ARGs expression. Results showed ROM directly affect SMX concentrations through the binding process, while CO and N-H groups were main binding sites for ROM. Dynamic changes of ROM molecular composition diversified the DOM pool due to microbe-mediated oxidoreduction, with enrichment of heteroatoms (N, S, P) and decreased aromaticity. Microbial community analysis showed SMX pressure significantly stimulated the succession of bacterial structure in both bulk water and rhizospheric biofilms. Furthermore, network analysis further confirmed ROM bio-labile compositions as energy sources and electron shuttles directly influenced microbial structure, thereby facilitating proliferation of antibiotic resistant bacteria (Methylotenera, Sphingobium, Az spirillum) and ARGs (sul1, sul2, intl1). This investigation will provide scientific supports for the control of antibiotic residues and corresponding ARGs in aquatic ecosystems.


Assuntos
Antibacterianos , Sulfametoxazol , Antibacterianos/farmacologia , Antibacterianos/química , Resistência Microbiana a Medicamentos/genética , Bactérias/genética , Bactérias/metabolismo , Genes Bacterianos , Rizosfera , Poluentes Químicos da Água/metabolismo , Poluentes Químicos da Água/química , Microbiota , Biofilmes
3.
Small ; : e2311552, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38501866

RESUMO

The activation of persulfates to degrade refractory organic pollutants is a hot issue in advanced oxidation right now. Here, it is reported that single-atom Fe-incorporated carbon nitride (Fe-CN-650) can effectively activate peroxymonosulfate (PMS) for sulfamethoxazole (SMX) removal. Through some characterization techniques and DFT calculation, it is proved that Fe single atoms in Fe-CN-650 exist mainly in the form of Fe-N3 O1 coordination, and Fe-N3 O1 exhibited better affinity for PMS than the traditional Fe-N4 structure. The degradation rate constant of SMX in the Fe-CN-650/PMS system reached 0.472 min-1 , and 90.80% of SMX can still be effectively degraded within 10 min after five consecutive recovery cycles. The radical quenching experiment and electrochemical analysis confirm that the pollutants are mainly degraded by two non-radical pathways through 1 O2 and Fe(IV)═O induced at the Fe-N3 O1 sites. In addition, the intermediate products of SMX degradation in the Fe-CN-650/PMS system show toxicity attenuation or non-toxicity. This study offers valuable insights into the design of carbon-based single-atom catalysts and provides a potential remediation technology for the optimum activation of PMS to disintegrate organic pollutants.

4.
Water Res ; 253: 121255, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38341971

RESUMO

Tracking nitrogen pollution sources is crucial for the effective management of water quality; however, it is a challenging task due to the complex contaminative scenarios in the freshwater systems. The contaminative pattern variations can induce quick responses of aquatic microorganisms, making them sensitive indicators of pollution origins. In this study, the soil and water assessment tool, accompanied by a detailed pollution source database, was used to detect the main nitrogen pollution sources in each sub-basin of the Liuyang River watershed. Thus, each sub-basin was assigned to a known class according to SWAT outputs, including point source pollution-dominated area, crop cultivation pollution-dominated area, and the septic tank pollution-dominated area. Based on these outputs, the random forest (RF) model was developed to predict the main pollution sources from different river ecosystems using a series of input variable groups (e.g., natural macroscopic characteristics, river physicochemical properties, 16S rRNA microbial taxonomic composition, microbial metagenomic data containing taxonomic and functional information, and their combination). The accuracy and the Kappa coefficient were used as the performance metrics for the RF model. Compared with the prediction performance among all the input variable groups, the prediction performance of the RF model was significantly improved using metagenomic indices as inputs. Among the metagenomic data-based models, the combination of the taxonomic information with functional information of all the species achieved the highest accuracy (0.84) and increased median Kappa coefficient (0.70). Feature importance analysis was used to identify key features that could serve as indicators for sudden pollution accidents and contribute to the overall function of the river system. The bacteria Rhabdochromatium marinum, Frankia, Actinomycetia, and Competibacteraceae were the most important species, whose mean decrease Gini indices were 0.0023, 0.0021, 0.0019, and 0.0018, respectively, although their relative abundances ranged only from 0.0004 to 0.1 %. Among the top 30 important variables, functional variables constituted more than half, demonstrating the remarkable variation in the microbial functions among sites with distinct pollution sources and the key role of functionality in predicting pollution sources. Many functional indicators related to the metabolism of Mycobacterium tuberculosis, such as K24693, K25621, K16048, and K14952, emerged as significant important factors in distinguishing nitrogen pollution origins. With the shortage of pollution source data in developing regions, this suggested approach offers an economical, quick, and accurate solution to locate the origins of water nitrogen pollution using the metagenomic data of microbial communities.


Assuntos
Microbiota , Poluentes Químicos da Água , Nitrogênio/análise , Rios/química , RNA Ribossômico 16S , Poluição da Água/análise , Monitoramento Ambiental , China , Poluentes Químicos da Água/análise
5.
J Colloid Interface Sci ; 660: 692-702, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38271805

RESUMO

Tetracycline (TC) antibiotics have been widely used over the past decades, and their massive discharge led to serious water pollution. Photo-Fenton process has gained ever-increasing attention for its excellent oxidizing ability and friendly solar energy utilization ability in TC polluted water treatment. This work introduced coordinative Fe into oxygen-enriched graphite carbon nitride (OCN) to form FeOCN composites for efficient photo-Fenton process. Hemin was chosen as the source to provide the source of coordinative Fe-Nx groups. The degradation efficiency of TC reached 82.1 % within 40 min of irradiation, and remained 76.9 % after five runs of reaction. The degradation intermediates of TC were detected and the possible degradation pathways were gained. It was found that h+, OH, and O2- played major roles in TC degradation. Notably, the photo-Fenton performance of FeOCN was stable in highly saline water or strong acid/base environment (pH 3.0-9.0). Besides, H2O2 can be generated in-situ in this photo-Fenton process, which is favorable for practical application. It can be anticipated that the coordinative FeOCN composites will promote the application of photo-Fenton oxidation process in TC polluted water treatment.

6.
Environ Res ; 246: 118200, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38220077

RESUMO

Organic polymers hold great potential in photocatalysis considering their low cost, structural tailorability, and well-controlled degree of conjugation for efficient electron transfer. Among the polymers, Schiff base networks (SNWs) with high nitrogen content have been noticed. Herein, a series of SNWs is synthesized based on the melamine units and dialdehydes with different bonding sites. The chemical and structural variation caused by steric hindrance as well as the related photoelectric properties of the SNW samples are investigated, along with the application exploration on photocatalytic degradation and energy production. The results demonstrate that only SNW-o based on o-phthalaldehyde responds to visible light, which extends to over 550 nm. SNW-o shows the highest tetracycline degradation rate of 0.02516 min-1, under 60-min visible light irradiation. Moreover, the H2O2 production of SNW-o is 2.14 times higher than that of g-C3N4. The enhanced photocatalytic activity could be ascribed to the enlarged visible light adsorption and intramolecular electron transfer. This study indicates the possibility to regulate the optical and electrical properties of organic photocatalysts on a molecular level, providing an effective strategy for rational supramolecular engineering to the applications of organic materials in photocatalysis.


Assuntos
Peróxido de Hidrogênio , Bases de Schiff , Luz , Antibacterianos , Polímeros
7.
Small Methods ; 8(3): e2301363, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38010986

RESUMO

The development of high-performance catalysts plays a crucial role in facilitating chemical production and reducing environmental contamination. Single-atom catalysts (SACs), a class of catalysts that bridge the gap between homogeneous and heterogeneous catalysis, have garnered increasing attention because of their unique activity, selectivity, and stability in many pivotal reactions. Meanwhile, the scarcity of precious metal SACs calls for the arrival of cost-effective SACs. Cobalt, as a common non-noble metal, possesses tremendous potential in the field of single-atom catalysis. Despite their potential, reviews about single-atom Co catalysts (Co-SACs) are lacking. Accordingly, this review thoroughly summarized various preparation methodologies of Co-SACs, particularly pyrolysis; its application in the specific domain of organic synthesis and environmental remediation is discussed as well. The structure-activity relationship and potential catalytic mechanism of Co-SACs are elucidated through some representative reactions. The imminent challenges and development prospects of Co-SACs are discussed in detail. The findings and insights provided herein can guide further exploration and development in this charming area of catalyst design, leading to the realization of efficient and sustainable catalytic processes.

8.
J Hazard Mater ; 460: 132363, 2023 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-37633017

RESUMO

As a rising branch of advanced oxidation processes, persulfate activation has attracted growing attention. Unlike catalysts that have been widely studied, the selection of persulfate is previously overlooked. In this study, the affecting factors of persulfates were studied. The effect of target pollutant properties on superior persulfate species (the species with a higher degradation efficiency) was investigated by multiwalled carbon nanotube (MWCNT)/persulfate catalytic systems. Innovatively, the EHOMO (or vertical ionization potential (VIP)) value of the target pollutant was proposed to be an index to judge the superior persulfate species, and the threshold is VIP= 6.397-6.674 eV, EHOMO= -8.035∼- 7.810 eV, respectively. To be specific, when the VIP of phenolic compounds is higher (or EHOMO of phenolic compounds is lower) than the threshold, the catalytic performance of peroxymonosulfate would be higher than that of peroxydisulfate. Moreover, the effects of coexisting cations on peroxydisulfate superior species were further investigated. It was illustrated that the hydrated cation radius of coexisting cations would influence the pollutant degradation efficiency under some circumstances. This study provides a new approach to improve the cost of persulfate activation systems and promotes the underlying downstream application of persulfate activation systems.

10.
J Hazard Mater ; 457: 131800, 2023 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-37302189

RESUMO

Heterogeneous Fenton-like process based on H2O2 activation has been widely tested for water purification, but its application still faces some challenges such as the use of high doses of chemicals (including catalysts and H2O2). Herein, a facile co-precipitation method was utilized for small-scale production (∼50 g) of oxygen vacancies (OVs)-containing Fe3O4 (Vo-Fe3O4) for H2O2 activation. Experimental and theoretical results collaboratively verified that H2O2 adsorbed on the Fe site of Fe3O4 tended to lose electrons and generate O2•-. While the localized electron from OVs of Vo-Fe3O4 could assist in donating electrons to H2O2 adsorbed on OVs sites, this allowed more H2O2 to be activated to •OH, which was 3.5 folds higher than Fe3O4/H2O2 system. Moreover, the OVs sites promoted dissolved oxygen activation and decreased the quenching of O2•- by Fe(III), thus promoting the generation of 1O2. Consequently, the fabricated Vo-Fe3O4 achieved much higher oxytetracycline (OTC) degradation rate (91.6%) than Fe3O4 (35.4%) at a low catalyst (50 mg/L) and H2O2 dosage (2 mmol/L). Importantly, further integration of Vo-Fe3O4 into fixed-bed Fenton-like reactor could effectively eliminate OTC (>80%) and chemical oxygen demand (COD) (21.3%∼50%) within the running period. This study provides promising strategies for enhancing the H2O2 utilization of Fe mineral.

11.
ISME J ; 17(7): 1104-1115, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37161002

RESUMO

Emerging evidence from genomics gives us a glimpse into the potential contribution of lysogenic bacteriophages (phages) to the environmental adaptability of their hosts. However, it is challenging to quantify this kind of contribution due to the lack of appropriate genetic markers and the associated controllable environmental factors. Here, based on the unique transformable nature of arsenic (the controllable environmental factor), a series of flooding microcosms was established to investigate the contribution of arsM-bearing lysogenic phages to their hosts' adaptation to trivalent arsenic [As(III)] toxicity, where arsM is the marker gene associated with microbial As(III) detoxification. In the 15-day flooding period, the concentration of As(III) was significantly increased, and this elevated As(III) toxicity visibly inhibited the bacterial population, but the latter quickly adapted to As(III) toxicity. During the flooding period, some lysogenic phages re-infected new hosts after an early burst, while others persistently followed the productive cycle (i.e., lytic cycle). The unique phage-host interplay contributed to the rapid spread of arsM among soil microbiota, enabling the quick recovery of the bacterial community. Moreover, the higher abundance of arsM imparted a greater arsenic methylation capability to soil microbiota. Collectively, this study provides experimental evidence for lysogenic phages assisting their hosts in adapting to an extreme environment, which highlights the ecological perspectives on lysogenic phage-host mutualism.


Assuntos
Arsênio , Bacteriófagos , Bacteriófagos/genética , Arsênio/toxicidade , Lisogenia , Bactérias/genética , Solo
12.
Angew Chem Int Ed Engl ; 62(20): e202300256, 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-36880746

RESUMO

Catalyst-free visible light assisted Fenton-like catalysis offers opportunities to achieve the sustainable water decontamination, but the synergistic decontamination mechanisms are still unclear, especially the effect of proton transfer process (PTP). The conversion of peroxymonosulfate (PMS) in photosensitive dye-enriched system was detailed. The photo-electron transfer between excited dye and PMS triggered the efficient activation of PMS and enhanced the production of reactive species. Photochemistry behavior analysis and DFT calculations revealed that PTP was the crucial factor to determine the decontamination performance, leading to the transformation of dye molecules. The excitation process inducing activation of whole system was composed of low energy excitations, and the electrons and holes were almost contributed by LUMO and HOMO. This work provided new ideas for the design of catalyst-free sustainable system for efficient decontamination.

13.
Water Res ; 233: 119719, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36801583

RESUMO

Organic pollutants removal from water is pressing owing to the great demand for clean water. Oxidation processes (OPs) are the commonly used method. However, the efficiency of most OPs is limited owing to the poor mass transfer process. Spatial confinement is a burgeoning way to solve this limitation by use of nanoreactor. Spatial confinement in OPs would (i) alter the transport characteristics of protons and charges; (ii) bring about molecular orientation and rearrangement; (iii) cause the dynamic redistribution of active sites in catalyst and reduce the entropic barrier that is high in unconfined space. So far, spatial confinement has been utilized for various OPs, such as Fenton, persulfate, and photocatalytic oxidation. A comprehensive summary and discussion on the fundamental mechanisms of spatial confinement mediated OPs is needed. Herein, the application, performance and mechanisms of spatial confinement mediated OPs are overviewed firstly. Subsequently, the features of spatial confinement and their effects on OPs are discussed in detail. Furthermore, environmental influences (including environmental pH, organic matter and inorganic ions) are studied with analyzing their intrinsic connection with the features of spatial confinement in OPs. Lastly, challenges and future development direction of spatial confinement mediated OPs are proposed.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Água , Oxirredução , Poluentes Químicos da Água/análise
14.
Environ Sci Technol ; 57(7): 2726-2738, 2023 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-36746765

RESUMO

The characterization of variations in riverine microbiota that stem from contaminant sources and transport modes is important for understanding biogeochemical processes. However, the association between complex anthropogenic nitrogen pollution and bacteria has not been extensively investigated owing to the difficulties faced while determining the distribution of nitrogen contaminants in watersheds. Here, we employed the Soil and Water Assessment Tool alongside microbiological analysis to explore microbial characteristics and their responses to complex nitrogen pollution patterns. Significant variations in microbial communities were observed in sub-basins with distinct land-water pollution transport modes. Point source-dominated areas (PSDAs) exhibited reduced microbial diversity, high number of denitrification groups, and increased nitrogen cycling compared with others. The negative relative deviations (-3.38) between the measured and simulated nitrate concentrations in PSDAs indicated that nitrate removal was more effective in PSDAs. Pollution sources were also closely associated with microbiota. Effluents from concentrated animal feeding operations were the primary factors relating to the microbiota compositions in PSDAs and balanced areas. In nonpoint source-dominated areas, contaminants from septic tanks become the most relevant sources to microbial community structures. Overall, this study expands our knowledge regarding microbial biogeochemistry in catchments and beyond by linking specific nitrogen pollution scenarios to microorganisms.


Assuntos
Microbiota , Poluentes Químicos da Água , Animais , Nitrogênio/análise , Nitratos/análise , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Água , Rios/química
15.
Sci Total Environ ; 871: 162048, 2023 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-36754314

RESUMO

Practical application of biochar may result in more biochar-derived dissolved organic matter (denoted as BDOM) inevitably release into surface waters by infiltration and surface runoff. The photochemical reaction of BDOM has gained intense attention, which played a key role in the fate of organic contaminants. However, the relationships between specific characteristics of BDOM and its photoreactivity are still uncertain. In this study, the characteristics of BDOM pyrolyzed from rice husk derived biochar at different temperature (from 400 °C to 700 °C) and their effect on the photodegradation of oxytetracycline (OTC) were carefully investigated. The 13C NMR and EEM results indicated the dominated component of BDOM was gradually turned from humic acid like substances with low aromaticity to high aromaticity with abundant oxygen-containing functional groups as pyrolytic temperature increases. Experimental results showed that the apparent rate constants (kobs) of BDOM700 (4.53 × 10-2 min-1) for OTC photodegradation was approximately one order of magnitude higher than BDOM400 (4.52 × 10-3 min-1), which was closely correlated with their aromaticity (R2 = 0.944). It was found that 3BDOM* rather than 1O2 played the major role in BDOM mediated photodegradation of OTC (80.13 % vs 14.34 %), and the carbonyl-containing group was identified as the main 3BDOM* precursor by NaBH4 reduction experiment. This work highlighted both aromaticity and carbonyl group contents were critical indicators for assessing the potential to generate 3BDOM* and corresponding photoreactivity.

16.
Chemosphere ; 314: 137733, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36603681

RESUMO

With the increasing of eutrophication in water body, algae blooms have become one of the global environmental problems. The cyanobacteria waste has placed a severe burden on the environment and transforming cyanobacteria into functional materials may be a wise approach. Herein, cobaltous sulfide/nitrogen-doped biochar (N-BC/CoSx) composite was synthesized by pyrolysis of cyanobacteria waste. The N-BC/CoSx showed excellent performance in peroxymonosulfate (PMS) activation for enrofloxacin (ENR) degradation, which could remove more than 90% ENR within 60 min. The influencing factors of pH and catalyst dosage on ENR removal efficiency were studied. The N-BC/CoSx showed good recyclability in the cycle runs. The radicals (O2•-, OH andSO4•-) and the non-radical species (charge transfer and 1O2) were generated in the ENR degradation. The cycle of Co(II)/Co(III) m ay contribute to the radical generation process. This work proved that metal sulfide modified cyanobacteria biochar has a specific application value in water pollution control and provides a new method for resource utilization of cyanobacteria.


Assuntos
Carbono , Poluentes Ambientais , Nitrogênio , Peróxidos , Cobalto
17.
Sci Total Environ ; 869: 161855, 2023 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-36708845

RESUMO

As an emerging environmental contaminant, the widespread of antibiotic resistance has caused a series of environmental issues and human health concerns. A load of antibiotic residues induced by agricultural practices have exerted selective pressure to bacterial communities in the soil-plant system, which facilitated the occurrence and dissemination of antibiotic resistance genes (ARGs) through horizontal gene transfer. As a result, the enrichment of ARGs within crops at harvest under the influence of food ingestion could lead to critical concerns of public health. In this review, the prevalence and dissemination of antibiotic resistance in the soil-plant system are highlighted. Moreover, different underlying mechanisms and detection methods for ARGs transfer between the soil environment and plant compartments are summarized and discussed. On the other hand, a wide range of influencing factors for the transfer and distribution of antibiotic resistance within the soil-plant system are also presented and discussed. In response to exposure of antibiotic residues and resistomes, corresponding hazard identification assessments have been summarized, which could provide beneficial guides of the toxicological tolerance for the general population. Finally, further research priorities for detection and management ARGs spread are also suggested.


Assuntos
Genes Bacterianos , Solo , Humanos , Solo/química , Antibacterianos/farmacologia , Bactérias/genética , Resistência Microbiana a Medicamentos/genética , Microbiologia do Solo
18.
Water Res ; 231: 119659, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36716570

RESUMO

Residual flotation reagents in mineral processing wastewater can trigger severe ecological threats to the local groundwater if they are discharged without treatment. Metal-free biochar-induced persulfate-advanced oxidation processes (KCBC/PS) were used in this study to elucidate the degradation of aniline aerofloat (AAF) - a typical flotation reagent. In KCBC/PS system, AAF can be removed at low doses of catalyst (KCBC, 0.05 g/L) and oxidant (PS, 0.3 mM) additions with high efficiency. The analysis revealed the dominance of O2•- among the identified reactive oxygen species (ROS), which achieved deeper mineralization for the AAF degradation in the KCBC/PS system. The role of the electron transfer mechanism was equally important; the importance was corroborated by the chemical quenching experiments, electron spin resonance (ESR) detection, probe experiments, and electrochemical analysis. It benefited from the electron transfer mechanism in the KCBC/PS system and exhibited a wide pH adaptation (3.5-11) and high resistance to inorganic anions for real mining wastewater treatment. Combined with theoretical calculations and other analyses, the carbonyl group was deemed to be the active site of the non-radical pathway of biochar, while the site of the conversion of SO4•- to superoxide radicals by biochar activation represented a defect. These findings revealed a synergistic effect of multiple active sites on PS activation in biochar-based materials. Moreover, the intermediate degradation products of AAF from mass spectrometry indicated a possible pathway through the density functional theory (DFT) method, which was effective in reducing the environmental toxicity of pollutants for the first time according to the T.E.S.T software and seed germination experiments. Overall, our study proposed a novel modification strategy for cost-effective and environmentally friendly biochar-based catalysts, while also deepening our understanding of the mechanism of activation of persulfate by metal-free carbon-based materials.


Assuntos
Elétrons , Poluentes Químicos da Água , Carvão Vegetal/química , Transporte de Elétrons , Oxirredução , Metais , Compostos de Anilina , Poluentes Químicos da Água/química
19.
Sci Total Environ ; 864: 161062, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36565867

RESUMO

Biochar has been frequently used as a persulfate (PS) activator due to its attractive properties, but dissolved organic matter (DOM) derived from the non­carbonized part of biochar has received less attention, not to mention its specific role and impact in biochar/PS systems. In this study, wheat straw, municipal sludge, and swine bone were selected as the representative feed stocks of biochar. Subsequently, these three types of biochar were adopted to explore the roles of DOM in biochar/PS systems. Although the composition and amount of DOM derived from different biochar were discrepant, they exhibited similar effect in biochar/PS systems. To be specific, the pore-clogging effect of DOM on biochar suppressed the adsorption capacity and catalytic performance of the three biochar. Furthermore, the removal of DOM decreased the environmental risk of these biochar/PS systems and enhanced the stability of the involved biochar. With respect to the variation in degradation mechanism, the removal of DOM increased the proportion of electron transfer pathway in unison, but the diminution in the roles of O2•¯ and 1O2 was more remarkable in bone-derived-biochar/PS systems. Additionally, the toxicity test illustrated that the leakage and accumulation of DOM were toxic to Chlorella sp., and the DOM from sludge-derived-biochar presented the highest toxicity. Overall, this study analyzes the roles of DOM derived from different biochar in biochar/PS systems and evaluates their environmental risk, which contributes to a comprehensive understanding of the fate of DOM derived from biochar.


Assuntos
Chlorella , Matéria Orgânica Dissolvida , Esgotos , Carvão Vegetal
20.
J Hazard Mater ; 442: 130078, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36303343

RESUMO

Microplastics (MPs) are substrates available for biofilms colonization in natural water environments. The biofilms formation may enhance the ability of MPs to adsorb harmful contaminants. Herein, we investigated the biofilms formation of three different MPs (PVC, PA and HDPE) in simulated natural environment, and observed the chemical structure, charge property, hydrophobicity and other properties of MPs affect microbial biomass and community composition. More importantly, potential pathogens were found in all three MPs biofilms. Furthermore, the adsorption capacities of original MPs and biological aging MPs for norfloxacin (NOR) was compared. HDPE has the largest adsorption capacity for NOR, while PA has the smallest adsorption capacity for NOR. It was concluded that the formation of biofilms enhanced the adsorption of NOR by 50.60 %, 24.17 % and 46.02 % for PVC, PA and HDPE, respectively. In addition, hydrogen-bond interaction, electrostatic interaction and hydrophobic interaction were found to dominate the adsorption of NOR by MPs. Our study contributed to improve the understanding of the interactions between aging MPs and contaminants in the natural water environments, and provided essential information for ecological risk assessment of MPs.


Assuntos
Microplásticos , Poluentes Químicos da Água , Plásticos/química , Adsorção , Antibacterianos , Polietileno/química , Cloreto de Polivinila , Poluentes Químicos da Água/análise , Biofilmes , Água , Água Doce
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