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81. 题目: Chemical-microbial effects of acetic acid, oxalic acid and citric acid on arsenic transformation and migration in the rhizosphere of paddy soil
文章编号: N23052511
期刊: Ecotoxicology and Environmental Safety
作者: Jianhao Yang, Xiaoxiao Liu, Caiyun Fei, Hongjuan Lu, Youhua Ma, Zhongwen Ma, Wenling Ye
更新时间: 2023-05-25
摘要:

Low-molecular-weight organic acids (LMWOAs) are essential components of rice roots exudates and an important source of soil organic carbon. The chemical-microbial pathway by which LMWOA affects arsenic (As) cycling in the rhizosphere of paddy soils is still unclear. In this study, three typical LMWOAs (acetic acid (AA), oxalic acid (OA), and citric acid (CA)) in rice root exudates were added to As-contaminated soil at a concentration of 10 mM, mimicking the rhizosphere environment. The results showed that the addition of AA and OA inhibited the mobilization of As in the rhizosphere soil. After 14 days of incubation, the content of As in the porewater of AA and OA decreased by 40% and 22%, respectively, compared with the control. AA hindered the mobilization of As in soil via promoting the formation of secondary minerals. The addition of OA inhibits the mobilization of As via increasing the proportion of As (V) in porewater and promoting the formation of secondary minerals in soil. In addition, OA addition not only significantly increased the aioA gene abundance but also notably enriched the microorganisms containing As (III) methylation functional genes (arsM). The addition of CA greatly expedited the release of As from the soil solid phase through the solubilization of Fe/Mn minerals via the effects of both soil chemistry and microbial action. Furthermore, linear discriminant analysis effect size (LEfSe) revealed the possibility that bacteria such as Burkholderia, Magnetospirillum, and Mycobacterium were involved in the reduction or methylation of As in the rhizosphere of paddy soil. This study revealed the internal causes of LMWOAs regulating As transformation and mobilization in flooded paddy soil and provided theoretical support for reducing As accumulation in rice by breeding rice varieties with high AA and OA secretions.

82. 题目: Evaluation of persulfate enhanced electrocoagulation (EC/PS) for bio-treated landfill leachate: Organics transformation pathways and carbon flow quantitative analysis
文章编号: N23052510
期刊: Chemical Engineering Journal
作者: Shuyan Guan, Jing Ding, Qingliang Zhao, Fan Liu, Qingwei Gao, Mallikarjuna N Nadagouda, Abdulaziz Al-Anazi
更新时间: 2023-05-25
摘要:

The sulfate radical-based advanced oxidation processes (SR-AOPs) have shown promise in treating bio-treated landfill leachate (BLL). However, little is known about the dissolved organic matter (DOM) transformation and reaction mechanisms at the molecular level after treating BLL using SR-AOPs. This study investigates the DOM degradation and transformation pathways during both electrocoagulation (EC) and persulfate enhanced electrocoagulation (EC/PS) of real BLL samples. The results indicate that the removal efficiency of chemical oxygen demand (COD) and total organic carbon (TOC) were enhanced to 46.34% and 36.39%, respectively, once persulfate is coupled with EC. Additionally, the removal of fluorescent contaminants in BLL significantly enhanced after treatment with EC/PS to 91.57%, 80.99%, and 39.10% for biogenic humic-like components C1, C2, and C3, respectively. A decrease in the proportion of macromolecular and aromatic matters was observed after the EC/PS process. The degree of oxidation of DOM was reduced, and the compounds with unstable structure and high biodegradability became the main compounds in the EC/PS effluent. The analysis of sediments generated by EC and EC/PS showed a similar composition of FeOOH and Fe3O4, although there was additional Fe2(SO4)3 in the EC/PS sludge. The degraded organics in the solution and sediment phase were quantified by material flow analysis, indicating that the precipitation was the main contributor to DOM removal during the EC/PS process. These findings aid in understanding the role of PS in the EC/PS process during real landfill leachate treatment and reevaluate the advantages and limitations of PS as an oxidant.

83. 题目: Electrochemical degradation of dissolved organic matters in oil sands process water using continuous-flow packed bed electrode reactor
文章编号: N23052509
期刊: Separation and Purification Technology
作者: Yue Ju, Chunwei Liu, Soliu O Ganiyu, Yuemin Zhao, Mohamed Gamal El-Din
更新时间: 2023-05-25
摘要:

In this study, the continuous-flow packed bed electrode reactor (PBER) was presented for the first time to reclaim oil sands process water (OSPW) generated during the bitumen extraction of oil sands surface mining. The PBER was constructed based on a traditional two-dimensional electrode system (2-DES) by packing pretreated spherical activated carbon (SAC) between the anode and cathode, forming the third electrode, charged and polarized under the electric field. The electrochemical treatment effect of three essential control factors, including cell voltage, electrode space, and flow rate, were investigated on the degradation of dissolved organic matters (DOMs) in OSPW. Electrolysis for 180 minutes under obtained optimal conditions: cell voltage 10 V, electrode space 6 cm and flow rate 5 mL/min, achieved 74.49% COD and 65.85% DOC removal percentage in PBER compared with only 11.72% and 12.97% achieved in 2-DES at similar conditions. The energy consumption and current efficiency were also significantly improved from 12.29 to 2.21 kW·h/g COD and 9.81% to 54.59%, respectively, thanks to the application of the third electrode. Further analysis revealed that the naphthenic acids (NAs), the primary source of acute toxicity in OSPW, were effectively degraded during PBER electrolysis, which was also validated by the Microtox® test that showed no acute toxicity in the PBER-treated OSPW, indicating that PBER could significantly improve the OSPW’s biodegradability. This study first demonstrated that PBER was a prospective technology for process water recycling in oil sands production and tailings ponds reclamation, particularly compared to the traditional 2-DES electrolysis.

84. 题目: Recovery through proper grazing exclusion promotes the carbon cycle and increases carbon sequestration in semiarid steppe
文章编号: N23052508
期刊: Science of the Total Environment
作者: Wenbo Zhang, Jing Li, Paul C Struik, Ke Jin, Baoming Ji, Shengyi Jiang, Yong Zhang, Yuanheng Li, Xiaojiang Yang, Zhen Wang
更新时间: 2023-05-25
摘要:

Grazing exclusion changes soil physical-chemical characteristics, rapidly affects microbial community composition and function, and alters biogeochemical processes, e.g., carbon (C) cycle, over time. However, the temporal dynamics of CO2 emission and CH4 uptake during grassland restoration chronosequences remain poorly understood. We investigated soil CO2 emission and CH4 uptake, the genes related to CO2 and CH4 production and reduction (cbbL, cbbM, chiA, and pmoA), and associated microbial communities under different durations of grazing exclusion (0, 7, 16, 25, and 38 years) to reveal the mechanisms and potential of soil CO2 emission and CH4 uptake in a semi-arid steppe. The results showed that a proper exclusion period could significantly improve soil physical-chemical conditions, vegetation community, and soil C-cycling. The abundance of C-cycling functional genes (cbbL, cbbM, chiA and pmoA), CH4 uptake and CO2 emission rates showed a single-peak pattern with increasing duration of grazing exclusion, peaking at 16 years and then decreasing in the period between 25 and 38 years, indicating that the effect of exclusion weakened when the exclusion period was too long. The changes in C-cycling functional genes and microbial communities are primarily influenced by aboveground net primary productivity (ANPP), and are associated with CO2, CH4, soil water content (SWC), and soil organic carbon (SOC). Structural equation modeling showed that increases in SOC content and pmoA abundance caused by an increase in ANPP accelerated CO2 emission and CH4 uptake rates, respectively. Our results provide valuable insights into the critical role of grazing exclusion in promoting grassland restoration and carbon sequestration, and have potential implications for sustainable land management practices.

85. 题目: Impact of Effluent Organic Matter on Perfluoroalkyl Acid Removal from Wastewater Effluent by Granular Activated Carbon and Alternative Adsorbents
文章编号: N23052507
期刊: Water Research
作者: Bahareh Tajdini, Hooman Vatankhah, Conner Murray, Alexander Liethen, Christopher Bellona
更新时间: 2023-05-25
摘要:

Occurrence of perfluoroalkyl acids (PFAAs) in wastewater effluent coupled with increasingly stringent regulations has increased the need for more effective sorption-based PFAA treatment approaches. This study investigated the impact of ozone (O3)- biologically active filtration (BAF) as integral components of non-reverse osmosis (RO)-based potable reuse treatment trains and as a potential pretreatment option to improve adsorptive PFAA removal from wastewater effluent by nonselective (e.g., granular activated carbon (GAC) and selective (e.g., anionic exchange resins (AER) and surface-modified clay (SMC)) adsorbents. For nonselective GAC, O3 and BAF resulted in similar PFAA removal improvements, while BAF alone performed better than O3 for AER and SMC. O3-BAF in tandem resulted in the highest PFAA removal performance improvement among pretreatments investigated for selective and nonselective adsorbents. Side by side evaluation of the dissolved organic carbon (DOC) breakthrough curves and size exclusion chromatography (SEC) for each pretreatment scenario suggested that despite the higher affinity of selective adsorbents towards PFAAs, the competition between PFAA and effluent organic matter (EfOM) (molecular weights (MWs) ∼100-1000 Da) negatively impacts the performance of these adsorbents. The SEC results also demonstrated that transformation of hydrophobic EfOM to more hydrophilic molecules during O3 and biotransformation of EfOM during BAF were the dominant mechanisms responsible for alleviating the competition between PFAA and EfOM, resulting in PFAA removal improvement.

86. 题目: Long-term manure and cropping systems effect on soil water vapour sorption characteristics is controlled by soil texture
文章编号: N23052506
期刊: Geoderma
作者: Fulai Yan, Yuting Fu, Marcos Paradelo, Fucang Zhang, Emmanuel Arthur
更新时间: 2023-05-25
摘要:

Increasing studies indicate that long-term experiments (LTEs) involving manure application and optimal cropping systems can significantly improve soil physicochemical properties, which may also affect the soil water retention curve (WRC) in the wet region (pF < 4.2). However, few studies have explored the effect of long-term manure application and cropping systems on soil WRC in the dry region (water vapour sorption isotherms, WSIs) (pF > 4.2) as well as the associated soil physicochemical properties. To overcome this knowledge gap, we investigated the effect of long-term manure application (24 to 177 years) and different cropping systems (71 to 82 years) on soil organic carbon (SOC) content, WSIs, hysteresis, and specific surface area (SSA). Soil samples were collected from five long-term manure experiments in Sweden, the United Kingdom, Spain, Germany, and Denmark, and two long-term cropping systems experiments in the United Kingdom. The five manure LTEs comprised three soil textures (silty clay, silt loam, and sandy loam) with one to four crops grown in the fields, including wheat, barley, maize, and grass/clover. The cropping system LTEs comprised silt loam and sandy loam including bare fallow (BF), arable rotation, ley–arable rotation, and permanent grass. Results showed that long-term manure application increased SOC content in each site, but it had little effect on the soil WSIs, hysteresis, and SSA in silty clay soils. The changes of soil WSIs, hysteresis, and SSA in silt loam and sandy loam arising from manure application largely depend on the crops grown in the field. For the long-term cropping systems experiments, permanent grass had the most significant effect in increasing SOC content, soil WSIs in silt loam and sandy loam, and hysteresis and SSA in silt loam compared to other treatments. Compared to BF, arable rotation and ley-arable rotation had no effect on SOC and soil WSIs in silt loam, and on hysteresis and SSA in silt loam and sandy loam. Multiple linear regression models including SOC, clay, and silt contents sufficiently explained the variabilities observed in the soil WSIs, hysteresis, and SSA for both manure and cropping systems LTEs.

87. 题目: Agricultural fire impacts on brown carbon during different seasons in Northeast China
文章编号: N23052505
期刊: Science of the Total Environment
作者: Yuan Cheng, Xu-bing Cao, Jiu-meng Liu, Qin-qin Yu, Qiang Zhang, Ke-bin He
更新时间: 2023-05-25
摘要:

Brown carbon (BrC) represents not only a major component of haze pollution but also a non-negligible contributor to positive radiative forcing, making it a key species for coordinating air quality and climate policies. In China, field observations on BrC remain limited given the highly variable emission sources and meteorological conditions across different regions. Here we focused on the optical properties of BrC in a distinct but rarely studied megacity in Northeast China, which is within a major agricultural region and experiences extremely cold winter. Agricultural fires were evident in April of 2021 and the fall of 2020, although open burning was strictly prohibited. Such emissions enhanced BrC's mass absorption efficiency at 365 nm (MAE365), more efficiently by the fall fires which were inferred to have relatively high combustion efficiencies (CE). After taking CE into consideration, the relationships between MAE365 and the levoglucosan to organic carbon ratio (a measure of the significance of agricultural fire influence) roughly converged for the fire episodes in different seasons, including those identified in February and March of 2019 by a previous campaign. Agricultural fires also influenced the determination of absorption Ångström exponent (AAE), by resulting in non-linearity for BrC's absorption spectra shown on ln-ln scale. Based on three indicators developed by this study, the non-linearity was inferred to be caused by similar chromophores although the fires were characterized by various CE levels in different seasons. In addition, for the samples without significant influence of open burning, coal combustion emissions were identified as the dominant influencing factor for MAE365, whereas none solid link was found between the solution-based AAE and aerosol source.

88. 题目: Removal of organophosphorus flame retardant by biochar-coated nZVI activating persulfate: Synergistic mechanism of adsorption and catalytic degradation
文章编号: N23052504
期刊: Environmental Pollution
作者: Liangzhong Li, Jianjun Li, Yile Yan, Ruixue Ma, Xiaohui Zhang, Jun Wang, Yi Shen, Habib Ullah, Lun Lu
更新时间: 2023-05-25
摘要:

Triphenyl phosphate (TPhP) is a typical aromatic-based non-chlorinated organophosphorus flame retardant, which has been widely detected in a variety of environments and poses high environmental and human health risks. In this study, biochar coated nano-zero-valent iron (nZVI) was fabricated to activate persulfate (PS) to degrade TPhP from water. A range of biochars (BC400, BC500, BC600, BC700, and BC800) was prepared as potential support to coat nZVI by pyrolyzing corn stalk at 400, 500, 600, 700 and 800 °C. As outperformed other biochars in adsorption rate, adsorption capacity, and less reluctant to be influenced by environmental factors (pH, humic acid (HA), coexistence of anions), BC800 was to act as support to coat nZVI (labeled as BC800@nZVI). SEM, TEM, XRD and XPS characterization showed that nZVI was successfully supported on the BC800. Removal efficiency of 10 mg L−1 TPhP by BC800@nZVI/PS could reach to 96.9% with a high catalytic degradation kinetic rate of 0.0484 min−1 under optimal condition. The removal efficiency remained stable in a wide pH range (3–9) and moderate concentration of HA and coexistence of anions, demonstrated the promising of using BC800@nZVI/PS system to eliminate TPhP contamination. Results from the radical scavenging and electron paramagnetic resonance (EPR) experiments demonstrated radical pathway (i.e. SO4·- and HO·) and non-radical pathway via 1O2 both play important role in TPhP degradation. The TPhP degradation pathway was proposed based on the six degradation intermediates analyzed by LC-MS. This study illustrated the synergistic mechanism of adsorption and catalytic oxidation removal of TPhP by BC800@nZVI/PS system, and provided a cost-efficient approach for TPhP remediation.

89. 题目: A neglected contributor of thermal hydrolysis to sludge anaerobic digestion: Fulvic acids release and their influences
文章编号: N23052503
期刊: Journal of Environmental Management
作者: Mingze Shi, Hongbo Liu, Xuedong Zhang, Yajie Li, Fang Huang, Cheng Zhao, Jun Guo, Ping Wu, He Liu
更新时间: 2023-05-25
摘要:

Fulvic acids (FAs) belong to inert organic matters in sewage sludge and their influences are often overlooked during convectional anaerobic digestion (AD). Currently, thermal hydrolysis (TH) has been widely applied on sludge pretreatment before AD processes, which makes FAs undergo drastic evolutions and aggressive to sludge AD. Results in the present study indicated that FAs concentration in the liquid was elevated by over incredible 150 folds during sludge TH, from 3.4 mg/L in raw sludge to 590.0 mg/L in hydrolyzed sludge at 180 °C. Moreover, during sludge TH, the chemical structures of FAs, including aromatic condensation degree, elemental composition and functional group, also underwent significant changes, which enhanced FAs electron transfer capability, reduced their biodegradability and promoted their roles on sludge AD. Furthermore, fortunately, the evolutions of FAs were favorable to sludge AD in general. Methane production could be promoted by about 20% under FAs concentration of 0.6 g/L, and the FAs extracted from hydrolyzed sludge presented higher promotion performances than that of the raw FAs, in which 180 °C FAs were particularly conspicuous. Furthermore, FAs evolutions would present differential influences on each phase of sludge AD, promotional to acidogenesis and methanogenesis but inhibitory to hydrolysis. Pearson correlation analysis indicated FAs influences on sludge AD, particularly the hydrolysis phase, were not only related to their concentration, but also chemical structure. The findings of this study demonstrated that FAs influences should not be negligible anymore during sludge AD with TH pretreatment. Meanwhile, since FAs promotion on sludge AD was closely related to their concentration and chemical structure, it would be significant to take FAs evolutions as auxiliary indexes for the regulations of sludge TH.

90. 题目: Biochar Promotes Arsenopyrite Weathering in Simulated Alkaline Soils: Electrochemical Mechanism and Environmental Implications
文章编号: N23052502
期刊: Environmental Science & Technology
作者: Shuai Wang, Peng Liao, Ling Cen, Hongguang Cheng, Qingyou Liu
更新时间: 2023-05-25
摘要: Oxidation dissolution of arsenopyrite (FeAsS) is one of the important sources of arsenic contamination in soil and groundwater. Biochar, a commonly used soil amendment and environmental remediation agent, is widespread in ecosystems, where it participates in and influences the redox-active geochemical processes of sulfide minerals associated with arsenic and iron. This study investigated the critical role of biochar on the oxidation process of arsenopyrite in simulated alkaline soil solutions by a combination of electrochemical techniques, immersion tests, and solid characterizations. Polarization curves indicated that the elevated temperature (5–45 °C) and biochar concentration (0–1.2 g·L–1) accelerated arsenopyrite oxidation. This is further confirmed by electrochemical impedance spectroscopy, which showed that biochar substantially reduced the charge transfer resistance in the double layer, resulting in smaller activation energy (Ea = 37.38–29.56 kJ·mol–1) and activation enthalpy (ΔH* = 34.91–27.09 kJ·mol–1). These observations are likely attributed to the abundance of aromatic and quinoid groups in biochar, which could reduce Fe(III) and As(V) as well as adsorb or complex with Fe(III). This hinders the formation of passivation films consisting of iron arsenate and iron (oxyhydr)oxide. Further observation found that the presence of biochar exacerbates acidic drainage and arsenic contamination in areas containing arsenopyrite. This study highlighted the possible negative impact of biochar on soil and water, suggesting that the different physicochemical properties of biochar produced from different feedstock and under different pyrolysis conditions should be taken into account before large-scale applications to prevent potential risks to ecology and agriculture.

91. 题目: Charge transfer interactions exist in extracellular polymeric substances: Comparison with natural organic matter
文章编号: N23052501
期刊: Chemosphere
作者: Ya Wang, Jiahai Ma
更新时间: 2023-05-25
摘要:

Extracellular polymeric substances (EPS) and natural organic matter (NOM) are widely present in the environment. While the molecular basis of NOM's optical properties and reactivity after treatment with sodium borohydride (NaBH4) has been successfully explained by the charge transfer (CT) model, the corresponding structure basis and properties of EPS remain poorly understood. In this work, we investigated the reactivity and optical properties of EPS after NaBH4 treatment, comparing them to the corresponding changes in NOM. After reduction, EPS exhibited optical properties and a reactivity with Au3+ similar to NOM, manifesting an irreversible loss of visible absorption (≥70%) associated with blue-shifted fluorescence emission (8–11 nm) and a lower rate of gold nanoparticles formation (decreasing by ≥ 32%), which can be readily explained by the CT model as well. Furthermore, the absorbance and fluorescence spectra of EPS were solvent polarity dependent, contrary to the superposition model. These findings contribute to an original understanding of the reactivity and optical properties of EPS and facilitate further cross-disciplinary studies.

92. 题目: Kinetic and Mechanistic Considerations of the Photosensitized Transformation of Chlorine in Chromophoric Dissolved Organic Matter Solutions under Simulated Solar Irradiation
文章编号: N23052415
期刊: Environmental Science & Technology
作者: Qi Li, Shuwen Yan, Ruiyang Xiao, Weihua Song
更新时间: 2023-05-24
摘要: Chlorination is one of the most common disinfection methods for water treatments. Although the direct photolysis of free available chlorine (FAC) induced by solar irradiation has been extensively investigated, the photosensitized transformation of FAC caused by chromophoric dissolved organic matter (CDOM) has not previously been examined. Our results suggest that the photosensitized transformation of FAC can occur in sunlit CDOM-enriched solutions. Interestingly, the photosensitized decay of FAC can be fitted using a combined zero- and first-order kinetic model. The photogenerated O2•– from CDOM contributes to the zero-order kinetic component. The reductive triplet CDOM (3CDOM*) contributes to the pseudo-first-order decay kinetic component. The bimolecular reaction rate constants of the model triplet (3-methoxyacetophenone) with HOCl and OCl were (3.6 ± 0.2) × 109 and (2.7 ± 0.3) × 109 M–1 s–1, respectively. Under simulated solar irradiation, the quantum yield coefficient of the reductive 3CDOM* toward FAC attenuation (fFAC = 840 ± 40 M–1) was 13 times greater than that of the oxidative 3CDOM* toward trimethylphenol (TMP) attenuation (fTMP = 64 ± 4 M–1). This study provides new insights into the photochemical transformation of FAC in sunlit surface waters, and the results are applicable when sunlight/FAC system is employed as an advanced oxidation process.

93. 题目: Humic acids alleviate aflatoxin B1-induced hepatic injury by reprogramming gut microbiota and absorbing toxin
文章编号: N23052414
期刊: Ecotoxicology and Environmental Safety
作者: Pengfei Xu, Shenghui Dong, Xinyuan Luo, Bin Wei, Cong Zhang, Xinyao Ji, Jing Zhang, Xiaoling Zhu, Guangfan Meng, Baolei Jia, Jie Zhang
更新时间: 2023-05-24
摘要:

Aflatoxin B1 (AFB1) is a hepatotoxic fungal metabolite that is widely present in food and can cause liver cancer. As a potential detoxifier, naturally occurring humic acids (HAs) may be able to reduce inflammation and restructure the gut microbiota composition; however, little is known about the mechanism of HAs detoxification as applied to liver cells. In this study, HAs treatment alleviated AFB1-induced liver cell swelling and the infiltration of inflammatory cells. HAs treatment also reinstated various enzyme levels in the liver disturbed by AFB1 and substantially alleviated AFB1-caused oxidative stress and inflammatory responses by enhancing immune functions in mice. Moreover, HAs increased the length of the small intestinal and villus height to restore intestinal permeability, which is impaired by AFB1. In addition, HAs reconstructed the gut microbiota, increasing the relative abundance of Desulfovibrio, Odoribacter, and Alistipes. In vitro and in vivo assays demonstrated that HAs could efficiently remove AFB1 by absorbing the toxin. Therefore, HAs treatment can ameliorate AFB1-induced hepatic injury by enhancing gut barrier function, regulating gut microbiota, and adsorbing toxin.

94. 题目: Soil organic carbon fractions in response to soil, environmental and agronomic factors under cover cropping systems: A global meta-analysis
文章编号: N23052413
期刊: Agriculture, Ecosystems & Environment
作者: Qijuan Hu, Ben W Thomas, David Powlson, Yingxiao Hu, Yu Zhang, Xie Jun, Xiaojun Shi, Yuting Zhang
更新时间: 2023-05-24
摘要:

Cover crops may improve soil health and increase soil carbon sequestration, thus contributing to both the adaptation to and mitigation of climate change. Despite these potential benefits, there currently lacks a global synthesis of the impacts of cover crops on soil organic carbon (SOC) fractions. We conducted a global meta-analysis of 93 peer-reviewed studies to quantify the effect of cover crops on changes in SOC fractions and the influence of environmental and management factors. Compared to bare soil management, cover crops increased SOC by 12% and increased seven SOC fractions, including microbial biomass carbon (MBC) by 33%, dissolved organic carbon (DOC) by 18%, particulate organic carbon (POC) by 15%, light-fraction organic carbon (LFOC) by 14%, permanganate oxidizable carbon (POXC) by 13%, short-term mineralizable carbon (SMC) by 10%, and mineral-associated organic carbon (MAOC) by 7%. The effect size of SOC was positively correlated with the effect sizes of MBC, POC, LFOC, and MAOC, but negatively correlated with the effect size of DOC. Soil taxonomic order and experimental duration were key factors affecting the beneficial effect of cover crops on the SOC fractions. Greater increases in SOC fractions due to cover crops were found in Entisols and Ultisols in comparison with other soil orders. The effect size of MAOC increased with experimental duration. Our study suggests that cover crops can significantly increase various SOC fractions, which likely serves as a building block for SOC sequestration and improvement of many aspects of soil health.

95. 题目: Biomarkers in fossil resins and their palaeoecological significance
文章编号: N23052412
期刊: Earth-Science Reviews
作者: J Pańczak, P Kosakowski, A Zakrzewski
更新时间: 2023-05-24
摘要:

Fossil resins are the one of several fossil tree products, together with leaves, wood, seeds, or pollen. As an emanation of organic matter, resins are made of organic compounds, predominantly terpenes. Terpenes are broadly identified from various living organisms such as higher plants, fungi, or bacteria. In fossil resins, these compounds occur in several forms – usually mono-, sesqui-, di-, and tri-terpenes. Some terpenes present in fossil resins provide information about their ancestors and the paleoenvironmental conditions during the resin expulsion. These compounds, known as biomarkers, preserve the original shapes of molecules or occur as altered structures. Due to the chromatographic methods, insight into the chemical structure of fossil resins is enabled and biomarkers might be detected. In this study, information about the state-of-the-art chromatographic research concerning fossil resins was gathered. The biomarkers found in fossil resins were divided into compounds providing chemotaxonomic (botanical biomarkers) and environmental information (other biomarkers). Botanical biomarkers provide high utility in paleobotanical studies. The initial identification of a source tree, gymnosperm, or angiosperm is possible, due to certain chemical patterns of these types. Moreover, in chemotaxonomic studies, the restriction to more specific taxonomic levels, especially to the level of family, is usually possible, thanks to the occurrence of specific biomarkers. Many terpenes that are known to have an ecological function in extant plants are also found in fossil resins; however, their presence does not clearly indicate the ecological properties of trees due to the advanced alterations of the chemical structure. However, some specific environmental biomarkers found in fossil resins (e.g. succinic acid or rosane) might provide information about the paleoenvironment during the resin deposition.

96. 题目: Fish muscle mercury concentration and bioaccumulation fluctuate year-round - Insights from cyprinid and percid fishes in a humic boreal lake
文章编号: N23052411
期刊: Environmental Research
作者: A J Piro, S J Taipale, H M Laiho, E S Eerola, K K Kahilainen
更新时间: 2023-05-24
摘要:

Boreal lakes demonstrate pronounced seasonality, where the warm open-water season and subsequent cold and ice-covered season dominate natural cycles. While fish muscle total mercury concentration (mg/kg) [THg] is well documented in open-water summer months, there is limited knowledge on the ice-covered winter and spring mercury dynamics in fish from various foraging and thermal guilds. This year-round study tested how seasonality influences [THg] and its bioaccumulation in three percids, perch (Perca fluviatilis), pikeperch (Sander lucioperca), ruffe (Gymnocephalus cernua), and three cyprinids, roach (Rutilus rutilus), bleak (Alburnus alburnus), and bream (Abramis brama) in the deep boreal mesotrophic Lake Pääjärvi, southern Finland. Fish were sampled and [THg] was quantified in the dorsal muscle during four seasons in this humic boreal lake. Bioaccumulation regression slopes (mean ± STD, 0.039 ± 0.030, range 0.013–0.114) between [THg] and fish length were steepest during and after spawning and shallowest during autumn and winter for all species. Fish [THg] was significantly higher in the winter-spring than summer-autumn in all percids, however, not in cyprinids. The lowest [THg] was observed in summer and autumn, likely due to recovery from spring spawning, somatic growth and lipid accumulation. Fish [THg] was best described by multiple regression models (R2adj: 52–76%) which included total length and varying combinations of seasonally changing environmental (water temperature, total carbon, total nitrogen, and oxygen saturation) and biotic factors (gonadosomatic index, and sex) in all species. The seasonal variation in [THg] and bioaccumulation slopes across multiple species suggests a need for standardized sampling seasons in long-term monitoring to avoid any seasonality bias. From the fisheries and fish consumption perspective in seasonally ice-covered lakes, monitoring of both winter-spring and summer-autumn would improve knowledge of [THg] variation in fish muscle.

97. 题目: Porous biochar derived from walnut shell as an efficient adsorbent for tetracycline removal
文章编号: N23052410
期刊: Bioresource Technology
作者: Qiyu Shi, Wangbo Wang, Hongmin Zhang, Huiling Bai, Kaiqiang Liu, Jianfeng Zhang, Zhihua Li, Weihuang Zhu
更新时间: 2023-05-24
摘要:

In this study, a high-performance porous adsorbent was prepared from biochar through a simple one-step alkali-activated pyrolysis treatment of walnut shells, and it was effective in removing tetracycline (TC). The specific surface area (SSA) of potassium hydroxide-pretreated walnut shell-derived biochar pyrolyzed at 900°C (KWS900) increased remarkably compared to that of the pristine walnut shell and reached 1713.87±37.05 m2·g−1. The maximum adsorption capacity of KWS900 toward TC was 607.00±31.87 mg·g−1. The pseudo-second-order kinetic and Langmuir isotherm models were well suited to describe the TC adsorption process onto KWS900. The KWS900 exhibited high stability and reusability for TC adsorption in the presence of co-existing anions or cations over a wide pH range of 1.0–11.0. Further investigations demonstrated that the proposed adsorption mechanism involved pore filling, hydrogen bonding, π–π stacking, and electrostatic interaction. These findings provide a valuable reference for developing biochar-based adsorbents for pollutant removal.

98. 题目: A fast and efficient tool for the structural characterization of marine dissolved organic matter: Nonuniform sampling 2D COSY NMR
文章编号: N23052409
期刊: Limnology and Oceanography: Methods
作者: Sahithya Phani Babu Vemulapalli, Christian Griesinger, Thorsten Dittmar
更新时间: 2023-05-24
摘要: An in-depth structural characterization of marine dissolved organic matter (DOM) is crucial for a better understanding of its connection to marine and global biogeochemical cycles. High-field nuclear magnetic resonance (NMR) spectroscopy in general and two-dimensional (2D) correlation spectroscopy (COSY) in particular are powerful tools for the molecular level structural analysis of marine DOM. These 2D NMR experiments demand prolonged experimental times of days to weeks per sample due to the requirement of a large number of experiments to record the second dimension (t1) of the 2D NMR experiment. Herein, we demonstrate the efficacy of nonuniform sampling (NUS) in 2D COSY, which (i) reduces the measurement time by half without compromising spectral quality and (ii) enhances the signal intensity for the given experiment time. This approach can lead to substantial progress in the structural analysis of previously poorly characterized marine DOM. NUS COSY has been exemplified on two solid-phase extracted DOM samples from the surface and deep ocean at 800 MHz and 1.2 GHz instruments. A dramatic improvement in sensitivity and spectral resolution is observed in NUS COSY spectra recorded at 1.2 GHz instrument when compared to 800 MHz instrument. NUS COSY NMR is versatile and anticipated to have significant potential for uncovering the hidden molecular diversity of DOM from various aquatic environments within a reasonable timeframe. The introduction of NUS into the environmental sciences was long overdue, and our study now opens the door for a wide field of new applications of NMR in the marine and aquatic sciences.

99. 题目: Removing siloxanes and hydrogen sulfide from landfill gases with biochar and activated carbon filters
文章编号: N23052408
期刊: Waste Management
作者: Mikko Selenius, Joonas Ruokolainen, Joakim Riikonen, Jimi Rantanen, Simo Näkki, Vesa-Pekka Lehto, Marko Hyttinen
更新时间: 2023-05-24
摘要:

Landfill gas (LFG) is formed by microorganisms within a landfill; it can be utilized as a renewable fuel in power plants. Impurities such as hydrogen sulfide and siloxanes can cause significant damage to gas engines and turbines. The aim of this study was to determine the filtration efficiencies of biochar products made of birch and willow to remove hydrogen sulfides, siloxanes, and volatile organic compounds from the gas streams compared to activated carbon. Experiments were conducted on a laboratory scale with model compounds and in a real LFG power plant where microturbines are used to generate power and heat. The biochar filters removed heavier siloxanes effectively in all of the tests. However, the filtration efficiency for volatile siloxane and hydrogen sulfide declined quickly. Biochars are promising filter materials but require further research to improve their performance.

100. 题目: Freeze-thaw treatment of bacteria significantly affects bacterial transport behaviors in both saturated and unsaturated porous media: Deep investigation the roles of flagella and extracellular polymeric substances
文章编号: N23052407
期刊: Science of the Total Environment
作者: Lei He, Jianmei Qin, Jia Guo, Shuai Wang, Haifeng Rong, Meiping Tong
更新时间: 2023-05-24
摘要:

The effects of freeze-thaw (FT) treatment and mechanisms on bacteria transport/retention in porous media with different moisture contents remain unclear. The transport/retention behaviors of bacteria with different FT treatment cycles (0, 1, and 3) in sand columns with different moisture contents (100 %, 90 %, 60 %, and 30 %) in NaCl solutions (10 and 100 mM) thus were investigated. Regardless of moisture content and solution chemistry, FT treatment increased bacteria deposition in sand columns, consistent with the results of QCM-D and visible parallel plate flow chamber (PPFC) systems. Via deep investigation of the contribution of flagella through using genetic-modified bacteria strain without flagella and that of extracellular polymeric substances (EPS) through analyzing its overall quantity, composition as well as the secondary structure of its two major components (proteins and polysaccharides), the mechanisms of FT treatment controlling bacterial transport/deposition were revealed. Although FT treatment induced flagella loss, it was not the major contributor to driving to the enhanced FT-treated cell deposition. Instead, FT treatment stimulated EPS secretion and increased its hydrophobicity (via increasing hydrophobicity of both proteins and polysaccharides), mainly contributing to the enhanced bacterial deposition. Even with copresent humic acid, FT treatment still enhanced bacterial deposition in sand columns with different moisture contents.

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