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Microbial fuel cells (MFCs) have gained remarkable attention as a novel wastewater treatment that simultaneously generates electricity. The low activity of the oxygen reduction reaction (ORR) remains one of the most critical bottlenecks limiting the development of MFCs. To date, although research on biochar as an electrocatalyst in MFCs has made tremendous progress, further improvements are needed to make it economically practical. Recently, biochars have been considered to be ORR electrocatalysts with developmental potential. In this review, the ORR mechanism and the essential requirements of ORR catalysts in MFC applications are introduced. Moreover, the focus is to highlight the material selection, properties, and preparation of biochar electrocatalysts, as well as the evaluation and measurement of biochar electrodes. Additionally, in order to provide comprehensive information on the specific applications of biochars in the field of MFCs, their applications as electrocatalysts, are then discussed in detail, including the uses of nitrogen-doped biochar and other heteroatom-doped biochars as electrocatalysts, poisoning tests for biochar catalysts, and the cost estimation of biochar catalysts. Finally, profound insights into the current challenges and clear directions for future perspectives and research are concluded.

Soil pollution endangers human health and ecological balance, which is why finding a highly efficient way to deal with pollutants is necessary. Biological method is an environmentally friendly treatment method. Bioelectrochemical systems (BESs), which combine electrochemistry with biological methods, have been widely used to remediate polluted environments, including wastewater, sludge, sediment, and soil. In BESs, redox reactions occur on electrodes with electroactive bacteria, which convert pollutants into low-polluting or nonpolluting substances. With BESs being a promising technology in the remediation field, the decontamination mechanisms and applications in soil conducted by BESs have attracted much attention. Therefore, to better understand the research progress of BESs, this paper mainly summarizes the mechanism of different classified BESs. The applications of microbial fuel cells (MFCs) in four pollutants (petroleum, heavy metals, pesticides, antibiotics) and the possible applications of microbial electrolysis cells (MECs) in soil are discussed. The main problems in BESs and possible future development directions are also evaluated.

Considering the stability and economy of immobilized enzymes, this study prepared co-modified biochar immobilized laccase product named Fe

Interactions between microorganisms and clay minerals influence the transport and cycling of metal contaminants in both marine and terrestrial environments. The present study was conducted to quantify the adsorption of dissolved cadmium, Cd(II), under seawater-like conditions to the marine cyanobacterium Synechococcus sp. PCC 7002, three common clay minerals (kaolinite, montmorillonite and illite), as well as cell-clay aggregates. We show here that the Synechococcus-only experiments removed the most Cd above pH 5.5, followed in decreasing order by aggregates of 50% cells:50% individual clays, aggregates of cells and all 3 clays, and individual clays. Electron microscope imaging showed that clays associated in a tangential edge-on orientation to the cells in Synechococcus-clay mineral aggregates. A non-electrostatic surface complexation modeling approach was used to fit Cd adsorption onto Synechococcus cells and individual clay minerals. The resulting Cd binding constants were then used in consort with surface functional group pKa values and site concentrations to accurately predict the extent of Cd adsorption onto the Synechococcus-clay mineral aggregates using the component additivity (CA) approach. We observed that the addition of cyanobacterial cells to clay mineral suspensions led to significantly larger mean aggregate sizes of clay minerals, enhancing the clay sedimentation rate. Although specifically focused on Cd, our study indicates that the ratio of bacterial plankton to clay minerals is an important determinant in terms of understanding the rate with which metals are transferred from the water column to the seafloor.

There is a growing need to eliminate antibiotic resistance genes (ARGs) in the environment and mitigate widespread antibiotic resistance. Graphitic carbon nitride (g-C3N4) was successfully synthesized via facile thermal polymerization approach and its potential for adsorption treatment of ARGs in water was examined. Batch adsorption experimental results revealed that g-C3N4 powders had robust adsorption activity for the gene ampC and ermB. Adsorption kinetics and isotherms were systematically investigated to explain the adsorption mechanism. The apparent adsorption equilibrium could be reached within 180 min. The adsorption process effectively removed ARGs (ampC and ermB) from water with 3.2 log and 4.2 log reductions, respectively. In addition, experimental data were analyzed by several models and simulated well with Langmuir isotherm and pseudo-second-order model. It indicated that adsorption process might be dominated by the chemical rate-limiting step. Moreover, the effects of temperature and pH on the removal of ARGs were conducted and the isoelectric point (IEP) was obtained. Finally, we have demonstrated that the g-C3N4 is a novel adsorbent and can be used as column packing to remove ARGs by filtration.

Highly efficient approaches using nanomaterials for ion capture and desalination have been widely explored to address fresh water scarcity worldwide; however, the complex preparation process and the large-scale and high-density perforation of porous graphene layers remain technical challenges. Herein, we found that sunlight-assisted tailoring of surface nanostructures involving controllable morphological and structural alterations of graphene unequivocally improved the ion adsorption and ion filtration performance. Notably, the interlayer spacing of single-layer graphene could be sufficiently tuned via lighting control to promote selective interactions between ions and nanosheets. After 7 d simulated sunlight treatment, the transformed SLG (SLG-S7) exhibited 86.1%, 77.3% and 46.1% increases of adsorption capacity for Na+, Pb2+ and Fe3+ in the complex ion system, respectively. Notably, the adsorption capacity of SLG-S7 for single Pb2+ was even 2.3-fold greater than that of pristine SLG. Further, the layer-stacked SLG-S7 membrane achieved super water fluxes (167.1 L m−2 h−1 bar−1) and a high separation performance without sacrificing salt ion rejection, which was attributed to the sunlight-induced larger water transport channels and defect-free nanosheets in the membrane. This work provides new insight for the design of novel graphene-based nanostructures to address the increasingly serious water contamination issue and the scarcity of fresh water.

Phenanthrene (PHE), mainly released from coal tar and petroleum distillation, is an important kind of prevalent polycyclic aromatic hydrocarbons (PAHs) contamination in China (up to 2.38 ± 0.02 mg/kg in soil and 8668 ng/L in surface water) and other countries in the world. Metal-organic frameworks (MOFs) show promising application prospects in the decontamination field, however, suffering from the intrinsic fragility and fine powder forms. Therefore, macroscopic MOFs architecture-sandwich-like Fe-ZIF-8/blue TiO

Over the past few decades, data-driven machine learning (ML) has distinguished itself from hypothesis-driven studies and has recently received much attention in environmental toxicology. However, the use of ML in environmental toxicology remains in the early stages, with knowledge gaps, technical bottlenecks in data quality, high-dimensional/heterogeneous/small-sample data analysis and model interpretability, and a lack of an in-depth understanding of environmental toxicology. Given the above problems, we review the recent progress in the literature and highlight state-of-the-art toxicological studies using ML (such as learning and predicting toxicity in complicated biosystems and multiple-factor environmental scenarios of long-term and large-scale pollution). Beyond predicting simple biological endpoints by integrating untargeted omics and adverse outcome pathways, ML development should focus on revealing toxicological mechanisms. The integration of data-driven ML with other methods (e.g., omics analysis and adverse outcome pathway frameworks) endows ML with widely promising application in revealing toxicological mechanisms. High-quality databases and interpretable algorithms are urgently needed for toxicology and environmental science. Addressing the core issues and future challenges for ML in this review may narrow the knowledge gap between environmental toxicity and computational science and facilitate the control of environmental risk in the future.

The transformation of silver ions (Ag

As typical pollutants, petroleum hydrocarbons that are widely present in various environmental media such as soil, water, sediments, and air, seriously endanger living organisms and human health. In the meantime, as a green environmental technology that integrates pollutant removal and resource recovery, bioelectrochemical systems (BESs) have been extensively applied to the removal of petroleum hydrocarbons from the environment. This review introduces working principles of BESs, following which it discusses the different reactor structures, application progresses, and key optimization factors when treating water, sewage sludges, sediments, and soil. Furthermore, bibliometrics was first used in this field to analyze the evolution of knowledge structure and forecast future hot topics. The research focus has shifted from the early generation of bioelectric energy to exploring mechanisms of soil remediation and microbial metabolisms, which will be closely integrated in the future. Finally, the future prospects of this field are proposed. This review focuses on the research status of bioelectrochemical degradation of petroleum hydrocarbons and provides a scientific reference for subsequent research.

D-amino acid (DAA) an environmentally friendly biofilm inhibitor, has low efficiency for membrane biofouling control due to its instability. To address this challenge, a novel nanocomposite was prepared with DAA adhering to polydopamine (PDA)-coated halloysite nanotube (HNTs) through the interactions of H-bonding and π-π stacking between PDA and DAA. Membrane modified with such nanocomposite was fabricated via blending phase inversion, and the nanocomposite was uniformly distributed in the modified membrane matrix. In comparison with the pristine membrane, the addition of nanocomposites resulted in robust mechanical property for modified membrane with the ultimate stress and strain increased by 23.97% and 35.62%, respectively. Moreover, an excellent tradeoff between water flux (2.5 folds of pristine membrane) and selectivity was achieved, probably due to the improved membrane hydrophilicity. Meanwhile, bovine serum protein (BSA) static adsorption as well as dynamic filtration experiments exhibited excellent antifouling ability of the modified membrane. Most importantly, a superior anti-biofouling stability over a 10-day period was obtained for the membrane modified with nanocomposite, indicating that the activity of DAA to mitigate biofouling was effectively maintained. This study developed a novel and promising strategy for membrane biofouling mitigation.

The Ag/ZnO/g-C3N4 composite photocatalyst, which was synthesized by thermal polymerization of a melamine precursor combined with solvothermal reaction, was used as a visible-light-driven biocide toward Escherichia coli (E. coli). The Ag/ZnO/g-C3N4 composite displayed considerably increased visible-light-driven bactericidal activity compared to g-C3N4, Ag/g-C3N4, and ZnO/g-C3N4 powders. The photocatalytic destruction of E. coli cells was verified by fluorescence-based cell live/dead analysis and SEM. The mechanism of increased bactericidal effect was studied by UV–vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, photocurrent response, and electrochemical impedance spectroscopy (EIS). The enhanced photocatalytic bactericidal effect was attributed to the matching conduction band levels of g-C3N4 and ZnO and the surface plasmon resonance (SPR) effect of Ag nanoparticles, which resulted in enhanced adsorption of visible light, reduced recombination of free charges, and rapid separation and transportation of photogenerated electrons-holes. The disinfection mechanism was investigated using different chemical scavengers and electron spin-resonance spectroscopy (ESR), and indicating the important role of h+ and H2O2. Furthermore, taking into account the bulk availability and better bactericidal effect of Ag/ZnO/g-C3N4, this work provides a new pathway to develop advanced materials for water disinfection.

The performance of a microbial fuel cell (MFC) that uses an as-prepared zeolitic imidazolate framework-8 (ZIF-8) as air-cathode catalyst is investigated. Due to the composite pore structure, large specific surface area (1416.19 m2/g), and high pore volume (0.55 cm³/g), the 0.5 mg/cm2 ZIF-8 catalyst can enhance the oxygen reduction reaction (ORR) in electrodes and achieve a maximum power density of 2103.4 mW/m2. X-ray photoelectron spectroscopy demonstrates the abundant existence of pyridinic nitrogen in ZIF-8 that meets the prerequisite for making an effective and efficient catalyst for ORR, and the carbon atoms adjacent to the pyridinic nitrogen are considered as the active sites with Lewis basicity. In addition, the graphitization of carbon in ZIF-8 enhanced the electronic conductivity and corrosion resistance during electrocatalysis. MFCs that use ZIF-8 as the catalyst can regularly work more than 110 h during a feeding period, which is considerably longer than that of the MFCs modified by Pt/C (approximately 40 h). The composite pore structure in ZIF-8 guarantees an rapid mass transfer rate on the three-phase boundary, which results in a faster ORR rate. These advantages make ZIF-8 a promising alternative catalyst for ORR of air-cathode MFC.

Soybean (Glycine max (L.) Merr.) has been a commercial oilseed crop in Canada since the 1920s. The production of soybean rapidly increased from 2004 to 2016 in Alberta and Manitoba. Root rot disease caused by the oomycete genus Pythium was observed from 105 fields in 2015 and 2016 in southern Alberta and Manitoba. In the present study, a total of 97 isolates of Pythium were recovered from the root tissues of soybean seedling collected from those fields. Identification of the Pythium species was achieved by examining their morphological features and sequences analysis of internal transcribed spacers (ITS) and cytochrome oxidase subunit 2 gene (Cox II). Nine species of Pythium were identified, with Pythium violae as the predominant species (27 out of 97, 27.8%), followed by P. intermedium (21), P. irregulare (16), P. sylvaticum (12), P. recalcitrans (8), P. ultimum (8), P. heterothallicum (3), P. conidiophorum (1) and P. macrosporum (1). This is the first report of P. conidiophorum, P. recalcitrans and P. violae on soybean in Canada. All the Pythium isolates except three isolates (S2d of P. violae, S29a and S29b of P. heterothallicum) were highly virulent on soybean, causing root rot disease symptoms.

In this work, activated carbon with ZnO laden on the surface was prepared by ZnCl2-one-step activation of different types of biomass (corn straw, bamboo powder and sawdust) and employed for mercury removal in the coal gas. During the activation, a part of ZnCl2 is converted into ZnO and laden on activated carbon, which greatly promotes the mercury removal performance with the presence of H2S. The ZnO content varies greatly with the content of SiO2 in the biomass due to its inactivation of ZnO and formation of Zn2SiO4. Carbonyl, which is important to mercury removal is largely retained after the activation at 500 °C and the amount of carbonyl seems to be positively correlated with the specific surface area (related to the lignin content). The temperature programmed desorption method was applied to further analyse the mercury adsorption in the coal gas. The results showed that ZnO and carbonyl play an important role in mercury removal, while the physisorption is not significant and only accounts for approximately 7% at 130 °C. The mechanism study showed that ZnO serves as a catalytic active site and catalyses the Hg0 into HgS with the presence of H2S. While the C O group of carbonyl acts as adsorption sites and turns into C O after the adsorption. This study provided a promising preparation method of mercury sorbents in the coal gas, and the influence of surface functional groups was also investigated in detail.

Lakes are critical for biogeochemical and ecological processes and are sensitive and vulnerable to anthropogenic disturbances, but how and to what extent human activities disturb the biodiversity in lakes remain unknown. Here, we showed the microbial diversity in 46 lakes and assessed the influence of 27 anthropogenic factors. We found that the economic level (e.g., per capita gross domestic product) was strongly negatively correlated (r = -0.97) with bacterial diversity but positively correlated (r = 0.17) with fungal diversity in lakes. The composition of the microbial community significantly changed with increasing economic level. Bacteria are more sensitive than fungi to anthropogenic impacts. Expanding the population size and increasing the economic level may promote the development of fungal diversity but inhibit bacterial diversity. Air quality, urbanization and ozone were negatively correlated with bacterial diversity, and fisheries had a negative correlation with fungal diversity. The anti-interference ability of lake microorganisms in the middle economic level zones (45,000-90,000 yuan/person) was stronger than that in high-level (90,000 yuan/person) and low-level (45,000 yuan/person) economic zones. Overall, our investigation provides national-scale evidence that changes in the microbial diversity in lakes were related to economic levels.

As an important type of typical synthetic azo dyes, the use of sudan I-IV dyes has been of concern worldwide because of their wide applications and illegal addition into various foodstuffs, potentially resulting in water and soil pollution and having adverse effects on human health and ecosystems. However, to date, little has been reported regarding the environmental levels of these dyes and the risks that they pose to human health and ecosystems. Understanding the responses of soil enzymes, functional groups of bacteria and microbial communities to sudan dyes is of great importance to reveal their effect on the soil environment. In this study, we performed a toxicological study on the specific and overall effects of sudan I-IV dyes on the activity of soil enzymes including catalase, urease, and alkaline phosphatase after a 2- and 7-day exposure, functional groups of soil bacteria including nitrogen-fixing, ammonia-oxidizing, and denitrifying bacteria on day 14, and the structure and diversity of soil microbial community compositions on day 30. The results showed that sudan I-IV affected the activity of the soil enzymes, the abundance of the bacterium functional groups, and the structure and diversity of microbial community compositions, and the effects varied by sudan dyes I-IV, the exposure concentration, and the exposure time.

The combined bioremediation of microorganisms and plant roots is an environmentally friendly soil remediation technology with the application prospect. The inefficiency of electron transfer hinders the decomposition of reluctant petroleum hydrocarbons and the further absorption by plant roots in plant-rhizosphere microbial electrochemical system. A conductive network of extracellular electron transfer was constructed in this study by the combination of magnetite and external electrode, committed to strengthening the process of Direct interspecific electron transfer (DIET), Dissimilation iron reduction (DIR), and long-distance electron transport. The microbial conversions of C, N, and Fe related to the hydrocarbon removal were investigated in the compound remediation system (Fe + MEC). Compared with the control group (PCK), an increased 174–232% of Total petroleum hydrocarbons (TPHs) was removed from Fe + MEC, accompanied by the generation of bio-current. Synchronously, the reduction of iron oxide (mainly DIR) and nitrogen (mainly denitrification) was promoted due to the rapid transfer of extracellular electrons. A reinforced synergistic network of the potential degradation, denitrification, and iron-reducing/exoelectrogenic bacteria was constructed in the compound system, which may be connected through the magnetite-mediated electron transport chain. The results in this study provide an insight into the impasse overcoming of inefficient electron transfer during the remediation of organic contaminated soil.

At present, the uptake and accumulation of nanoplastics by plants have raised particular concerns. However, molecular mechanisms underlying nanoplastic phytotoxicity are still vague and insufficient. To address this scientific gap, we analyzed the transcriptome response of hydroponically grown wheat (Triticum aestivum L.) to polystyrene nanoplastics (PSNPs) (100 nm) by integrating the differentially expressed gene analysis (DEGA) and the weighted gene correlation network analysis (WGCNA). PSNPs could significantly shape the gene expression patterns of wheat in a tissue-specific manner. Four candidate modules and corresponding hub genes associated with plant traits were identified using WGCNA. PSNPs significantly altered carbon metabolism, amino acid biosynthesis, mitogen-activated protein kinase (MAPK) signaling pathway-plant, plant hormone signal transduction, and plant-pathogen interaction Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. In addition, some Gene Ontology (GO) terms associated with the metal ion transport were further screened. These findings shed new light on the phytotoxic mechanism and environmental implication behind the interaction of nanoplastics and crop plants, and advance our understanding of the potential adverse effect induced by the presence of nanoplastics in agricultural systems.

Zeolitic imidazole frameworks (ZIFs) have attracted a considerable amount of attention for use in environmental applications (e.g., pollutant adsorption and photocatalysis in water treatments). The environmental stability and toxicity of ZIFs are key prerequisites for their practical applications, but information about these factors is largely lacking. The present work finds that pristine ZIFs (ZIF-8 and ZIF-67) photodegrade from frame structures into two-dimensional nanosheets and are oxidized to zinc carbonate (ZIF-8) and Co3O4 (ZIF-67) under visible-light irradiation. The photoinduced electrons, holes and free radicals promote dissolution of the metal cores and organic ligands, leading to collapse of the frame structure. The photodegradation of ZIF-8 alleviates developmental inhibition, oxidative stress, plasmolysis, and photosynthetic toxicity, while the photodegradation of ZIF-67 aggravates nanotoxicity. The integration of metabolomics and transcriptomics analysis reveals that unsaturated fatty acid biosynthesis and metal ion-binding transcription contribute to the altered toxicity of ZIF photodegradation. These findings highlight the roles of photodegradation in structural transformation and alteration of the toxicity of ZIFs, alarming the study of pristine metal-organic frameworks (MOFs).

Mitigating membrane fouling extensively occurred in membrane-based water treatment techniques in an efficient and durable way is a pressing challenge. The novel electro-assisted membrane coupling technology showed great potentials for tackling the problem. Foulants like charged natural organic matter, colloids and bacteria can be successfully repelled from membrane surface in the presence of electric field, contributing to less adoption, accumulation, and blocking. More importantly, the inactivation of microorganisms induced by electric field played a significant role in inhibiting the formation of the stubborn biofilm, which showed distinct and excellent advantages over other membrane fouling control approaches like surface hydrophilic modification, chemical cleaning, and pretreatment optimization. This thorough and long-term effective coupling means will actually open a new sight for membrane fouling mitigation fields. Herein, we reviewed the configuration of direct current (DC) membrane coupling technology to control membrane fouling, fouling alleviating mechanisms, and membrane filtration performances of DC electric field membrane coupling process. Additionally, some potential drawbacks and corresponding strategies were also discussed; hopefully to supply some viewpoints for prospective developments in membrane fouling mitigation fields.

Previous studies have shown that co-catalysts play a pivotal role for improving both the activity and reliability of semiconductors in photocatalytic hydrogen production, however, designing highly efficient and cost-effective co-catalysts to replace expensive and rare metals is still a big challenge. In this work, DFT (density functional theory) is utilized to guide the application of CoP NWs (nanowires) as an earth-abundant co-catalyst for photocatalytic hydrogen production. Metallic 1D CoP NWs is rationally integrated with Zn0.5Cd0.5S solid solution semiconductor for the first time, to induce a remarkably improved photocatalytic hydrogen production activity of 12,175.8 μmol h−1 g−1, which is 22 times higher than that of the pristine Zn0.5Cd0.5S. This outstanding activity benefits from the collaborative advantages of excellent metallic conductivity and the rigid 1D nanostructure of CoP NWs. Moreover, the mechanism investigations demonstrate that this excellent activity arises from the strong electronic coupling, favourable band structure, highly efficient charge separation and migration based on the powerful characterizations, such as time-resolved PL decay spectra and photoelectrochemical methodology. This work brings new opportunities to employ 1D co-catalysts on photocatalysts for improving the catalytic activities in hydrogen production from water.

A novel Au-graphene oxide (GO)-Co3O4 hollow sphere (Au/GO-Co3O4) was synthesized and its potential in binding with antibiotic resistance genes (ARGs) and inhibiting their replication was examined in this study. Tetracycline-resistant genes (tetA) with two amplicon lengths were selected as the model ARGs due to its highly detected in the environment. The Au/GO-Co3O4 composite was synthesized using tetra-n-butylammonium bromide (TBAB) as a mediating proxy. We found that it could bind with tetA and consequently inhibit its replication to a greater extent compared with pure Co3O4 and GO-Co3O4 hybrid. Furthermore, the Au-GO-Co3O4 composite was more efficient in binding with short fragments of tetA-ARGs (S-tetA) than long fragments (L-tetA). The interaction mechanism between the composite and tetA was systematically analyzed using spectra methods (FTIR, Raman, UV–Vis, and fluorimetric spectra), isolated filtrate assays, and gel electrophoresis. It is found that the adsorption of both GO and gold nanoparticles for tetA as well as cleavage effect of cobalt oxide/cobalt ions played a critical role in the capture and damage of tetA. Furthermore, we found that the interaction of both Co3O4 and GO-Co3O4 with tetA was mainly through intercalation mechanism, however, that of Au/GO-Co3O4 with tetA was mainly through groove binding mechanism. These findings in this study throw light on the new approaches for purification of ARGs contaminated water and elimination of antibiotic resistance of ARGs by novel inhibitor.

Hydrolysis is generally considered as the main pathway for the degradation of ester-type pollutants in aquatic environments. In this study, we found that when methanol or ethanol presented as the external carbon in the activated sludge, transesterification is very important for the degradation of para-hydroxybenzoic acid esters (parabens). In the activated sludge solutions with 1% methanol added, contribution of transesterification to the degradation of the propyl substituted paraben (PrP) and ethyl substituted paraben (EtP) accounted for 46% and 83%, respectively, in the early stage of the reaction. This indicates that in aquatic environments with alcohols presence, parabens prefer to form small molecule homologues than hydrolysis to acid. The predominant transesterification in the activated sludge is related to enzyme preference. Amano lipase from Pseudomonas fluorescens was verified to catalyze hydrolysis and transesterification of parabens, while the latter was dominant in water solution with 1% methanol or ethanol. Considering the common application of small molecular alcohols as the external carbon sources in wastewater treatment plants, transesterification might be an important pathway for the degradation of parabens pollutants in these engineering aquatic environments.

Much attention has been paid to extracting and isolating specific and well-known nanoparticles (especially for engineered nanomaterials) from complex environmental matrices. However, such research may not provide global information on actual contamination because nanoscale fragments exist as mixtures of various elements and matrices in the real environment. The present work first isolated and characterized nanoscale fragments in effluents from municipal wastewater treatment plants (WWTPs). The nanoscale fragments were found to be composed of 70–85% carbon and low amounts of oxygen, heavy metals and other elements and exhibited nanosheet topographies (approximately 0.87–1.31 nm thickness and 68–187 nm lateral length). Because the isolated nanoscale fragments were mixtures rather than one specific type of nanoparticle, they were present at high concentrations ranging from 0.07 to 0.55 mg/L. It was also found that the accumulation of nanoscale fragments in rice reached 0.59 mg/g under exposure to environmentally relevant concentrations, leading to marked phytotoxicity (e.g., ultrastructural damage to chloroplasts and mitochondria). Metabolic analysis revealed the toxicological mechanisms to be related to disorders of carbohydrate, amino acid and fatty acid metabolism. This study is the first to characterize the properties and analyze the toxicity of nanoscale fragments in the effluents of WWTPs. Given that WWTP effluents containing nanoscale fragments are continuously discharged to the soil, surface water and seas, nanoscale fragment materials deserve considerable attention in future work compared with the few widely studied engineered nanoparticles.

Ordered mesoporous Ag/CeO 2 nanocomposites were prepared by combining nanocasting with photo-assisted reduction. The heterogeneous photoreactivity of the prepared samples was tested for inactivating Escherichia coli ( E. coli ). These mesoporous Ag/CeO 2 nanocomposites exhibited superior photocatalytic disinfection efficiency than mesoporous CeO 2 and bulk CeO 2 , respectively. Doping Ag species could extend the absorption range to visible light area and enhance the concentration of Ce 3+ ions and oxygen vacancies, which had significant influence on the surface properties of CeO 2 . Moreover, it is the first time to verify that created midgap states through doping Ag can significantly lower the threshold of incident photon energy and broaden the adsorption spectrum demonstrated by experimental studies and density functional theory (DFT) calculations. The enhanced disinfection mechanism was attributed to the fact that the novel mesoporous structure can promote the mass transfer process and the interfacial interaction between Ag species and CeO 2 and lead to reduced recombination of free charges, rapid separation and transportation of photogenerated electrons-holes. This work provides a new method to develop novel mesoporous plasmonic photocatlysts for disinfection using solar radiation.

Soybean (Glycine max (L.) Merr.) has excellent potential as an alternative crop to canola in southern Alberta farming systems. However, soybean is susceptible to Fusarium root rot, which usually results in the occurrence of dead or dying plants in mid-to-late summer and severe reductions in yield. A total of 102 isolates identified as Fusarium were recovered from diseased soybean root samples collected from central and southern Alberta from 2011 to 2013. Ten species of Fusarium were identified, with F. acuminatum as the predominant species (31 out of 102 isolates, 30.39%), followed by F. equiseti (16.67%), F. culmorum (13.73%), F. avenaceum (10.78%), F. oxysporum (8.82%), F. redolens (7.84%), F. torulosum (4.90%), F. tricinctum (2.94%), F. commune (1.96%) and F. proliferatum (0.98%). This is the first report of F. commune, F. redolens and F. torulosum causing root rot in soybean in Canada. Phylogenetic analyses based on sequence data from the translation elongation factor 1-α (EF-1α) and the internal transcribed spacer (ITS) region were used to evaluate genetic variation and, in conjunction with morphological characters, for species identification. All of the Fusarium isolates were able to infect soybean, although some exhibited varying levels of aggressiveness.

Soil contaminated by aged petroleum hydrocarbons is faced with scarcity of electron acceptors, low activity of functional microbes and inefficient electron transfer, which hinder the bioremediation application. The soil microbial fuel cell (MFC) simultaneously solves these problems with bioelectricity production. In this study, five types of surfactants were introduced to enhance the bioavailability of aged petroleum hydrocarbon in soils. The ampholytic surfactant (lecithos) was optimal due to the highest bioelectricity generation (0.321C d −1 g −1 ) and promoted hydrocarbon degradation (328%), while the nonionic (glyceryl monostearate) and cationic (cetyltrimethylammonium bromide) surfactants were inefficient. The surfactants induced a special microbial enrichment affiliated with Proteobacteria , Firmicutes , Bacteroidetes , Actinobacteria , Chloroflexi , Planctomycetes and Acidobacteria (93%–99% of total) in soil MFCs. The anionic surfactant (sodium dodecyl sulfate) exhibited the strongest selectivity, and α- proteobacteria and γ - proteobacteria abundances decreased while Clostridia increased, much like the result obtained with the biosurfactant β -cyclodextrin. Furthermore, Bacillus abundance was increased in connected soil MFCs, except addition of lecithos in which Clostridium increased to 14.88% from 3.61% in the control. The high correlations among Bacillus , Phenylobacterium , Solibacillus (0.9162–0.9577) and among Alcaligenes , Dysgonomonas , Sedimentibacter (0.9538–0.9966) indicated a metabolic network of microorganisms in the soil bioelectrochemical remediation system.

Root rot is a major constraint on field pea ( Pisum sativum L.) production. Species of Phytophthora can cause seed rot, pre- and post-emergence damping-off, and stem and root rot in many legume crops, but have not been reported in association with pea root rot in Canada. Following a survey of pea fields in Alberta, Canada, in 2015, root tissue with typical symptoms of root rot was plated onto a growth medium, and one isolate was identified as a putative Phytophthora spp. based on its colony characteristics. The isolate was homothallic, producing smooth, thick-walled oospores and both paragynous and amphigynous antheridia on lima bean agar. The sporangia were ovoid or elliptical, non-papillate, and had internal proliferations. Based on these criteria, the isolate was tentatively identified as Phytophthora sansomeana . Sequencing of the internal transcribed spacer (ITS) and Cox II regions revealed 100% identity with the ITS and Cox II sequences of P. sansomeana available in GenBank, confirming this identification. A pathogenicity test indicated that the isolate was pathogenic and caused pre-emergence damping-off, root discoloration, and root rot with brown to dark brown lesions on pea cultivars. This is the first report of P. sansomeana causing root rot in pea in North America.

Molybdenum disulfide (MoS2) poses great potential in water treatment as a popular transition metal dichalcogenide, arousing considerable concern regarding its fates and risk in aquatic environments. This study revealed that the interplay with extracellular polymeric substances (EPS) of freshwater algae significantly changed the properties and toxicity of MoS2 to aquatic fish. The predominant binding of aromatic compounds, polysaccharides, and carboxyl-rich proteins in EPS on the 1T polymorph of MoS2 via hydrophilic effects and the preferential adsorption of carboxylic groups contributed to morphological alterations, structural disorders (band gap and phase alterations), and the attenuated aggregation of MoS2 in aqueous solutions. Electron charge transfer and n-π* interactions with EPS decreased the catalytic activity of MoS2 by inhibiting its capability of generating reactive intermediates. The dissolution of MoS2 slowed down after interacting with EPS (from 0.089 to 0.045 mg/L per day) owing to rapid initial oxidation (i.e., forming Mo-O bond) and carbon grafting. Notably, the morphological and structural alterations after EPS binding alleviated the toxicity (e.g., malformation and oxidative stress) of MoS2 to infantile zebrafish. Our findings provide insights into the environmental fate and risk of MoS2 by ubiquitous EPS in natural waters, serving as valuable information while developing water treatment processes accordingly.

Electronic regulation via interfacial formation is identified as a versatile strategy to improve the electrocatalytic activity. Herein, we report a feasible electrospinning-pyrolysis approach for the in-situ immobilization of Co/MnO hetero-nanoparticles onto N,S co-doped carbon nanotubes/nanofiber-integrated hierarchical branched superstructures (abbreviated as Co/MnO@N,S-C NT/CNFs hereafter). The simultaneous realization of interfacial engineering and nanocarbon hybridization renders the fabricated Co/MnO@N,S-C NT/CNFs with abundant firmly anchored active sites, modified electronic configuration, improved electric conductivity, efficient mass transport pathways, and significantly reinforced stability. Profiting from the compositional synergy and architectural advantages, the Co/MnO@N,S-C NT/CNFs exhibit outstanding ORR activity, superior tolerance to methanol, and excellent long-term stability in KOH electrolyte. More encouragingly, as a proof-of-concept demonstration, the rechargeable aqueous and flexible all-solid-state Zn-air batteries using Co/MnO@N,S-C NT/NFs + RuO2 as the air-cathode afford higher power densities, larger specific capacities and superb cycling stability, outperforming the state-of-the-art Pt/C + RuO2 counterparts. This work demonstrates the great contribution of heterointerfaces for oxygen electrocatalysis.

The Development of transformative technology capable of producing inexpensive superior lithium electroactive anode material with low volume changes and stable performance on cycling is an important step on the path to advanced application of lithium ion batteries (LIBs). In this work, a new synthesis strategy for hybrid SnO2-Co3O4 nanotubes, based on electrospun polyvinylpyrrolidone (PVP) fibers with co-embedded metal precursors is explored. This low cost, template-free, Kirkendall effect-derived process first yields phase-separated core-sheath PVP/SnO2-Co3O4 composites, creating highly uniform and well-dispersed nanotubes via self-assembly accompanying gradual PVP combustion. Control experiments show that the heat-treatment atmosphere is the key for the in situ growing in a large yield. On account of the great buffering capability in hierarchical porous architecture, synergistic effect of active multi-components and the present interfacial Co nanophase, the proposed tubular hybrids possess enhanced cyclic stability and lithium storage capacity as anodes with retained capacity as high as 873 mAh g−1 even after 200 cycles at 100 mA g−1. The protocol paves the way for rational design of hollow hybrid nanotubes with wide applications.

Elaborate design of cost-effective and highly-efficiency bifunctional electrocatalysts towards the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is critically essential for the advancement of rechargeable metal-air batteries. Herein, we develop a straightforward and scalable hydrogel-bridged pyrolysis strategy for the exquisite construction of a “ship-in-a-bottle”-structured bifunctional catalyst consisting of fine CoFe nanoparticles encapsulated inside the carbon nanowall-assembled frameworks (abbreviated as CoFe@N-CNWF hereafter). The deliberate design of such intriguing hierarchical honeycomb-like architecture with tightly confined CoFe nanoparticles and open configuration endows the as-fabricated CoFe@N-CNWF with sufficient well-dispersed active sites, rapid charge transfer efficiency, accelerated mass diffusion and robust mechanical strength. Consequently, the resultant CoFe@N-CNWF catalyst shows outstanding catalytic performance toward the ORR and OER with high activity and long-term stability. More encouragingly, a rechargeable Zn–air battery using CoFe@N-CNWF as the air cathode displays superb energy density, high energy efficiency and robust reversibility, surpassing the state-of-the-art precious Pt/C + RuO2–assembled counterpart. The developed methodology for the fabrication of “ship-in-a-bottle” architectures may open new opportunities to low-cost, mass production of high-efficiency bifunctional oxygen electrocatalysts for a variety of renewable energy technologies and beyond.

The development of stable, adequate, and cost-effective catalysts to meet current fuel cell requirements is urgent in the face of ever-intensifying energy demands. Heteroatom-doped carbons are promising non-noble metal-based catalysts expected to replace or reduce platinum consumption required for the electrocatalytic oxygen reduction reaction (ORR). Metal–organic frameworks (MOFs) are rapidly evolving as porous functional materials owing to their high surface area, permanent porosity, and diverse structure, thus rendering their derivatives suitable potential catalysts for electrocatalysis. Herein, we systematically reviewed the latest advances in the design and synthesis of MOF-derived heteroatom-doped carbons, which were further divided into metal-free and metal-containing materials to identify the effects of component manipulation, morphological control, and structural engineering on their ORR performance. Additionally, future challenges and research directions for MOF-derived heteroatom-doped carbon electrocatalysts are proposed.