Synthesis of Hydrogen Peroxide in Neutral Media by an Iron-Doped Nickel Phosphide Catalyst.

The two-electron oxygen reduction reaction (2e ORR) for electrochemical hydrogen peroxide (HO) synthesis has drawn much attention due to its eco-friendly, cost-effective, and highly efficient properties. Developing catalysts with excellent HO production rates and selectivity is still a big challenge. In this work, an iron-doped nickel phosphide (Fe-Ni-P) catalyst was synthesized by a solvent thermal method.

Adsorption Mechanism and Regeneration Performance of Calcined Zeolites for Hydrogen Sulfide and Its Application.

Hydrogen sulfide (HS) is a very toxic, acidic, and odorous gas. In this study, a calcined zeolite was used to investigate the adsorption performance of HS. Among particle size, calcination temperature and time calcination temperature and time had significant effects on the adsorption capacity of HS on the zeolite.

Biochar enhanced the stability of toluene removal in extracted groundwater amended with nitrate under microaerobic conditions.

Groundwater pollution caused by the leakage of petroleum and various fuel oils is becoming a serious environmental problem. In this study, carbon-based materials including biochar and hydrochar were applied to investigate the effects of additives on the toluene removal in the extracted groundwater under microaerobic condition with the addition of nitrate. Biochar and hydrochar could adsorb toluene, and thus enhance the toluene removal in the system.

Effects of Fe-modified digestate hydrochar at different hydrothermal temperatures on anaerobic digestion of swine manure.

Hydrothermal carbonization temperature is a key factor in controlling the physico-chemical properties of hydrochar and affecting its function. In this study, effects of hydrochar and Fe-modified hydrochar (Fe-HC) prepared at 180 °C (180C-Fe), 220 °C (220C-Fe) and 260 °C (260C-Fe) on anaerobic digestion (AD) performance of swine manure was investigated. Among the three Fe-HCs, 220C-Fe had the highest amount of Fe and Fe on the surface.

Metagenomic insights into phenanthrene biodegradation in electrical field-governed biofilms for groundwater bioremediation.

Electrical fields (EFs)-assisted in-situ bioremediation of petroleum-contaminated groundwater, such as polycyclic aromatic hydrocarbons, has drawn increasing attention. However, the long-term stability, the EFs influence, and metabolic pathways are still poorly understood, hindering the further development of robust technology design. Herein, a series of EFs was applied to the phenanthrene-contaminated groundwater, and the corresponding system performance was investigated.

Eutrophication levels increase sulfur biotransformation and emissions from sediments of Lake Taihu.

Eutrophication can stimulate the emissions of volatile sulfur compounds (VSCs) accompanied by variations in environmental variables in lakes. However, the effects of eutrophication on VSC emissions from lake sediments as well as the underlying mechanisms remain unclear. In this study, depth gradient sediments at different eutrophication levels and seasons were collected from Lake Taihu to investigate the response of sulfur biotransformation in the sediments to eutrophication based on the analysis of environmental variables, microbial activity, abundance and community structure.

Synergy effects of Methylomonas koyamae and Hyphomicrobium methylovorum under methanethiol stress.

Methanotrophs are able to metabolize volatile organic sulfur compounds (VOSCs), excrete organic carbon during CH oxidation, and influence microbial community structure and function of the ecosystem. In return, microbial community structure and environmental factors can affect the growth metabolism of methanotrophs. In this study, Methylomonas koyamae and Hyphomicrobium methylovorum were used for model organisms, and methanethiol (MT) was chosen for a typical VOSC to investigate the synergy effects under VOSC stress.

Characterization of methanotrophic community and activity in landfill cover soils under dimethyl sulfide stress.

Landfill cover soil is the environmental interface between landfills and the atmosphere and plays an important role in mitigating CH emission from landfills. Here, stable isotope probing microcosms with CH or CH and dimethyl sulfide (DMS) were carried out to characterize activity and community structure of methanotrophs in landfill cover soils under DMS stress. The CH oxidation activity in the landfill cover soils was not obviously influenced at the DMS concentration of 0.

Hydrothermal treatment enhances energy recovery from pig manure digestate and improves the properties of residues.

Energy recovery from biowaste is of high significance for a sustainable society. Herein, hydrothermal treatment (HT) was applied to valorize pig manure digestate. The effects of hydrothermal operational parameters, including temperature (130-250 °C), residence time (15-90 min), and total solid (TS) concentration (10%-20%), on reducing sugar yield were investigated in this study.

Aminolipids elicit functional trade-offs between competitiveness and bacteriophage attachment in Ruegeria pomeroyi.

Lipids play a crucial role in maintaining cell integrity and homeostasis with the surrounding environment. Cosmopolitan marine roseobacter clade (MRC) and SAR11 clade bacteria are unique in that, in addition to glycerophospholipids, they also produce an array of amino acid-containing lipids that are conjugated with beta-hydroxy fatty acids through an amide bond. Two of these aminolipids, the ornithine aminolipid (OL) and the glutamine aminolipid (QL), are synthesized using the O-acetyltransferase OlsA.

Additional ratios of hydrolysates from lignocellulosic digestate at different hydrothermal temperatures influencing anaerobic digestion performance.

Hydrothermal treatment (HT) is envisaged as a promising technology to treat the lignocellulosic biomass. HT temperature is an important parameter influencing the hydrolysate compositions such as organic compounds and potential inhibitors, and therefore affect the subsequential anaerobic digestion (AD) process. Herein, HT-AD was employed to treat the wheat straw-derived digestate.

Characteristic pollutants and microbial community in underlying soils for evaluating landfill leakage.

Leachate leakage poses a serious environmental risk to the safety of surrounding soils and groundwater. A much faster approach to reflect landfill leakage is the premise to mitigate the ecological risk of landfills. In this study, two landfills (BJ and WZ) were selected to investigate the leaching characteristics of various pollutants along the vadose soil depths.

Estimation of sulfur fate and contribution to VSC emissions from lakes during algae decay.

Algae decay is an important process influencing environmental variables and emissions of volatile sulfur compounds (VSCs) in eutrophic lakes. However, effects of algae decay on VSC emissions from eutrophic lakes as well as fate of algae-derived sulfur remain poorly understood. In this study, simulated algae-sediment systems were used to explore the flow and distribution of sulfur during algae decay.

Characterization of anaerobic oxidation of methane and microbial community in landfills with aeration.

Landfills are the third largest source of anthropogenic CH emissions. Anaerobic oxidation of methane (AOM) activity and communities of methane-oxidizing bacteria were investigated in three informal landfills in this study, namely, BJ, CH and SZ landfills, among which BJ and CH represent traditional anaerobic landfills, while the SZ landfill was subjected to aeration to accelerate waste stabilization. The AOM rates of the investigated landfilled wastes ranged from 3.

Eutrophic levels and algae growth increase emissions of methane and volatile sulfur compounds from lakes.

Eutrophic lakes are hot spots of CH and volatile sulfur compound (VSC) emissions, especially during algal blooms and decay. However, the response of CH and VSC emissions to lake eutrophication and algae growth as well as the underlying mechanisms remain unclear. In this study, the emissions of CH and VSCs from four regions of Lake Taihu with different eutrophic levels were investigated in four months (i.

Intermittent aeration reducing NO emissions from bioreactor landfills with gas-water joint regulation.

Landfills are important emission sources of atmospheric NO, especially bioreactor landfills with leachate recirculation. In this study, NO emissions were characterized in four bioreactor landfills with different ventilation methods, including intermittent (2-h aeration per 12 h or 4 h/d in continuous) and continuous aeration (20 h/d), in comparison to a traditional landfill without aeration. During the experiment, the NO emissions from the landfill reactors with intermittent aeration were 7.

CS increasing CH-derived carbon emissions and active microbial diversity in lake sediments.

Lakes are important methane (CH) sources to the atmosphere, especially eutrophic lakes with cyanobacterial blooms accompanied by volatile sulfur compound (VSC) emissions. CH oxidation is a key strategy to mitigate CH emission from lakes. In this study, we characterized the fate of CH-derived carbon and active microbial communities in lake sediments with CS used as a typical VSC, based on the investigation of CH and VSC fluxes from Meiliang Bay in Lake Taihu.

Chemical and microbiological characterization of pig manures and digestates.

Livestock and poultry breeding modes, feed compositions and manure collection systems have regional characteristics, which can directly affect the composition of livestock and poultry breeding manure, energy production by anaerobic digestion and resource utilization of products. The chemical, heavy metal contents and microbiological characteristics of pig manures and digestates were characterized in five pig farms and biogas plants in Quzhou (Zhejiang Province) in this study. The results showed that hemicellulose and cellulose of pig manures could be partly degraded in anaerobic digestion, but lignin was difficultly degraded and accumulated in digestates.

Reduction in VOC emissions by intermittent aeration in bioreactor landfills with gas-water joint regulation.

Landfill mining and reclamation is a new strategy for addressing the lack of space available for new landfills and realizing the sustainable development of landfills. A gas-water joint bioreactor landfill is regulated by injecting water and/or recirculating leachate, and a blasting aeration system to optimize waste stabilization. In this study, four landfill reactors were constructed to investigate the effects of ventilation methods, including continuous (20 h d) and intermittent aeration (4 h d in continuous or 2-h aeration per 12 h, twice a day), on the degradation of organic matter and volatile organic compound (VOC) emissions in comparison with traditional landfills.

Metabolic flexibility of aerobic methanotrophs under anoxic conditions in Arctic lake sediments.

Methane (CH) emissions from Arctic lakes are a large and growing source of greenhouse gas to the atmosphere with critical implications for global climate. Because Arctic lakes are ice covered for much of the year, understanding the metabolic flexibility of methanotrophs under anoxic conditions would aid in characterizing the mechanisms responsible for limiting CH emissions from high-latitude regions. Using sediments from an active CH seep in Lake Qalluuraq, Alaska, we conducted DNA-based stable isotope probing (SIP) in anoxic mesocosms and found that aerobic Gammaproteobacterial methanotrophs dominated in assimilating CH.

Effects of different pretreatment methods on biogas production and microbial community in anaerobic digestion of wheat straw.

The pretreatment of wheat straw has been recognized to be an essential step prior to anaerobic digestion, owing to the high abundance of lignocellulosic materials. In order to choose economical and effective techniques for the disposal of wheat straw, effects of five pretreatment methods including acid, alkali, co-pretreatment of acid and alkali, CaO, and liquid digestate of municipal sewage sludge on anaerobic digestion of wheat straw were investigated by analyzing biogas production and organic matter degradation in the study. The results showed that among these pretreatment methods, the methane yield was highest in the liquid digestate pretreated-wheat straw with 112.

Stable-isotopic and metagenomic analyses reveal metabolic and microbial link of aerobic methane oxidation coupled to denitrification at different O levels.

Aerobic methane (CH) oxidation coupled to denitrification (AME-D) can not only mitigate CH emission into the atmosphere, but also potentially alleviate nitrogen pollution in surface waters and engineered ecosystems, and it has attracted substantial research interest. O concentration plays a key role in AME-D, yet little is understood about how it impacts microbial interactions. Here, we applied isotopically labeled KNO and CH and metagenomic analyses to investigate the metabolic and microbial link of AME-D at different O levels.

Effects of oxygen tension on the microbial community and functional gene expression of aerobic methane oxidation coupled to denitrification systems.

Aerobic CH oxidation coupled to denitrification (AME-D) can not only mitigate the emission of greenhouse gas (e.g., CH) to the atmosphere, but also reduce NO and/or NO and alleviate nitrogen pollution.