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17461. 题目: Accelerated degradation of pharmaceuticals by ferrous ion/chlorine process: Roles of Fe(IV) and reactive chlorine species
文章编号: N21051404
期刊: Science of The Total Environment
作者: Yuanxiang Mao, Jialiang Liang, Fangying Ji, Huiyu Dong, Lei Jiang, Qiushi Shen, Qian Zhang
更新时间: 2021-05-14
摘要: In this study, we determined the mechanisms and kinetics of the degradations of ibuprofen (IBP) and sulfamethoxazole (SMX), and identified the active species contributions in ferrous ion (Fe(II))/free chlorine (FC) system. Reactive chlorine species (RCS) were the major contributor to the degradations of IBP (73.0%) and SMX (59.3%), respectively, at pH 3. Due to the low reaction rates between Fe(IV) and target pollutants (kFe(IV), IBP = (1.5 ± 0.03) × 103 M−1 s−1 and kFe(IV), SMX = (4.8 ± 0.2) × 103 M−1 s−1) and the low [Fe(IV)]ss ((5.0 ± 0.6) × 10−8 M), Fe(IV) was not the main contributor and only contributed 0.17% and 0.86% to the degradation of IBP and SMX, respectively, at pH 3. The degradations of pharmaceuticals were facilitated by acidic conditions. Chloride (Cl−) accelerated the degradation of SMX and had a weak effect on the degradation of IBP. Natural organic matter limited the degradation of IBP and SMX. Overall, we demonstrated that multiple active oxidants (Fe(IV) and RCS) are produced by Fe(II)/FC and elucidated the mechanism of active oxidants degradation of pollutants.

17462. 题目: Acid precipitation followed by microalgae (Chlorella vulgaris) cultivation as a new approach for poultry slaughterhouse wastewater treatment
文章编号: N21051403
期刊: Bioresource Technology
作者: Ruly Terán Hilares, Kiara A. Garcia Bustos, Fabio P. Sanchez Vera, Gilberto J. Colina Andrade, David A. Pacheco Tanaka
更新时间: 2021-05-14
摘要: Poultry slaughterhouse wastewater (PSW) contains high organic matter and nutrients requiring thus a special treatment before its final disposal. In this way, acid precipitation (H2SO4) followed by microalgae “Chlorella vulgaris” cultivation both in batch and continuous processes was studied as an alternative method for PSW treatment. By reducing the pH value of PSW from 6-7 to 4, about 80 % of the global chemical oxygen demand (CODT) was removed as sludge. In the supernatant, the COD residual was efficiently removed (83 %) by microalgae in the batch process, using an internal-loop concentric tube photobioreactor (4.5 L). Moreover, in continuous process, after 89h, the COD value resulted lower than 200 mg L-1 and 1.2 g L-1 of microalgae in the output line. The proposed PSW treatment method is promising from economic and environmental viewpoints, since the microalgal biomass can be valued in a biorefinery context.

17463. 题目: Hydrological controls on marine chemistry in the Cryogenian Nanhua Basin (South China)
文章编号: N21051402
期刊: Earth-Science Reviews
作者: Meng Cheng, Zihu Zhang, Thomas J. Algeo, Shuliang Liu, Xiaodan Liu, Haiyang Wang, Biao Chang, Chengsheng Jin, Wen Pan, Mengchun Cao, Chao Li
更新时间: 2021-05-14
摘要: In order to explore Cryogenian seawater chemistry and its underlying controls, we present an integrated study of iron speciation, major and trace elements, and carbon isotopes of Mn‑carbonates and their host black shales in the Datangpo Formation from three drillcores (Gaodi, Xixibao and Changxingpo) in the Nanhua Basin, South China. A key aspect of this analysis was use of the B/Ga, Sr/Ba, and S/TOC proxies to evaluate paleosalinity variation in this marginal-marine basin. Our results indicate that salinity and redox conditions as well as cycling of Fe-Mn-C in the basin were hydrologically controlled by the relative fluxes of freshwater from riverine sources and seawater from open-ocean sources. Black shale deposition was associated with low-brackish salinity, probably due to reduced seawater exchange, which contributed to development of stagnant watermass circulation and euxinia in the basin. During such anoxic depositional intervals, Mo show gradient across the basin. In contrast, Mn‑carbonate deposition was associated with relatively higher salinity linked to enhanced exchange of the basinal watermass with the global ocean and to improved deep-water ventilation, which was due to sinking of higher-density ingressing open-ocean waters below lower-density basinal waters (as in the modern Baltic Sea). Enhanced decay of organic matter led to 12C-enriched dissolved inorganic carbon that was precipitated in Mn‑carbonates on the deep basin floor, leading to spatial gradient of inorganic carbon isotope. The shift from euxinic to ferruginous deep-water conditions during such intervals implies that ingressing oceanic waters were sulfate-poor relative to basinal waters. These depositional intervals were also characterized by operation of an active MnFe shuttle that enhanced accumulation of Fe2+, Mn2+, Mo and [CO32−] in the deep watermass. Our findings demonstrate that the seawater chemistry of the Cryogenian Nanhua Basin was significantly influenced by hydrological factors of both local and global character, and that similarities should be expected for all Cryogenian epicratonic seas, providing new insights into Cryogenian oceanic chemistry evolution and the contemporaneous formation of widespread Mn‑carbonate mines.

17464. 题目: Spartina alterniflora saltmarsh soil organic carbon properties and sources in coastal wetlands
文章编号: N21051401
期刊: Journal of Soils and Sediments
作者: Jin-e Liu, Dailan Deng, Caiyu Zou, Ruiming Han, Yue Xin, Zihao Shu, Li-min Zhang
更新时间: 2021-05-14
摘要: Purpose We investigated S. alterniflora saltmarshes in 10 regions to distinguish the major sources of soil organic carbon (SOC) and provide data for SOC content in Chinese coastal wetlands under exotic invasion. Methods We collected soil and plant samples. We analyzed the soil properties for SOC content, recalcitrant organic carbon (RC), labile organic carbon (LC), total nitrogen (TN), total phosphorus (TP), total salinity and water content, as well as stable isotopic carbon composition (δ13C) in the SOC and RC. SOC and RC were determined using a Shimadzu TOC analyzer. We used δ13C values and C/N ratios of the SOC to identify carbon source inputs. The δ13C of the SOC and RC was measured using a Sercon Integra CN isotope ratio mass spectrometer. Results The results showed that the S. alterniflora saltmarsh SOC pool properties differed significantly between study areas, dependent upon local circumstances and carbon exchanges. The δ13C values of SOC in surface sediments from Tianjin to Guangxi were from −25.16 to −20.64‰, RC from −27.82 to −23.1‰, and C/N ratios between 11.36 and 19.00. These samples had SOC values of 14.77–23.95 g kg−1, RC values of 11.98–21.44 g kg−1, and LC values of 0.44–4.08 g kg−1. The SOC and RC of surface sediments were positively correlated with TN and TP. Conclusions S. alterniflora saltmarsh SOC is derived from multiple carbon inputs including from marine and land sources and its formation is driven by complicated factors. TN and TP inputs increase SOC in coastal wetlands. Generally, terrigenous carbon inputs dominate the SOC composition in Chinese coastal wetlands, although marine-derived organic carbon (OC) inputs to sediment increase from northern to southern areas.

17465. 题目: The impact of the Amazon on the biological pump and the air‐sea CO 2 balance of the Western Tropical Atlantic
文章编号: N21051319
期刊: Global Biogeochemical Cycles
作者: Domitille Louchard, Nicolas Gruber, Matthias Münnich
更新时间: 2021-05-13
摘要: The Amazon River strongly modifies the biogeochemistry of the Western Tropical Atlantic (WTA). To disentangle the different mechanisms driving these modifications, we conduct a series of modelling experiments with a high resolution regional ocean model (ROMS) coupled to a biogeochemical/ecological model (BEC) that we augmented to include Diatom‐Diazotroph‐Assemblages (DDAs). In our model, the Amazon river increases net primary production (NPP) in the WTA by almost 10%, exceeding the stimulation expected from the supplied inorganic nitrogen and phosphorus by a factor of two. This amplification is fueled by new nitrogen stemming from DDA‐driven N2 fixation in the plume region, supported, in part, by the consumption of riverine dissolved organic phosphorus. The vertical export of organic carbon is amplified by a shift of the phytoplankton community towards diatoms induced by the large amount of Si(OH)4 delivered by the Amazon. These changes in NPP and export production induce a strong uptake of atmospheric CO2. In contrast, the remineralization of the river‐delivered terrestrial organic matter leads to a release of CO2 over the WTA, which is partially offset by a net uptake induced by the riverine dissolved inorganic carbon and alkalinity. Overall, the Amazon reduces the strong outgassing of the WTA in our simulations by more than 50 %. Our study demonstrates how rivers modify the marine biological pump and the air‐sea CO2 fluxes in the downstream ocean through a myriad of cascading effects, highlighting the need to fully consider the land‐ocean aquatic continuum in the modeling of the Earth System.

17466. 题目: Beer lees and ceramsite amendments enhance the two-stage co-composting of green waste
文章编号: N21051318
期刊: Bioresource Technology
作者: Yifan Bai, Lu Zhang, Zexin Yin, Xiangyang Sun
更新时间: 2021-05-13
摘要: Composting is a major way to process green waste (GW), and amendments are important in GW composting. In this study of the two-stage co-composting of GW, beer lees (0, 25, 30%) and/or ceramsite (0, 10, 15%) were assessed as amendments. Changes in bulk density, porosity, temperature, pH, gaseous emissions, dissolved organic carbon (DOC) and nitrogen (DON), lignocellulose degradation, microbial abundances, and phytotoxicity were assessed during GW composting with the amendments. Treatments with a combination of beer lees and ceramsite had positive effects, and 25% beer lees and 15% ceramsite optimized all compost parameters. The optimal combination of amendments extended the thermophilic phase, enhanced the lignocellulose decomposition, and generated a stable and mature product in 20 days. Consequently, the best final compost was not phytotoxic (germination index: 164%), was mature (void space ratio: 48.48, pH: 7.20, and DOC/DON ratio: 0.51), and nutrient-rich (especially for N: 5.13%, P: 1.84%, and K: 0.68%).

17467. 题目: Application of rice straw and horse manure coameliorated soil arbuscular mycorrhizal fungal community: Impacts on structure and diversity in a degraded field in Eastern China
文章编号: N21051317
期刊: Land Degradation & Development
作者: Zihao Liu, Jianfeng Bai, Hua Qin, Dongnian Sun, Minghui Li, Junli Hu, Xiangui Lin
更新时间: 2021-05-13
摘要: Organic amendments are powerful tools for mitigating land degradation, improving soil fertility and biodiversity. Nevertheless, changes in the diversity and activity of arbuscular mycorrhizal (AM) fungi during the initial period of soil restoration under different organic amendments (e.g., crop residues and livestock manure) remains poorly understood despite their growing roles in improving soil sustainability. We conducted a six‐month experiment with the application of rice straw (RS), horse manure (HM), and both amendments (RH) to an artificially degraded field in Eastern China, and the AM fungal community structure was assessed through Illumina sequencing. The dominance (35.2%) of the identified operational taxonomic units (OTUs) belonged to Glomus, whereas the majority (66.0%) of the recovered sequence reads belonged to Paraglomus. Although no notable changes in AM fungal abundance were observed, the relative abundance of Claroideoglomus significantly increased (p < .05) to 4.3% in the HM‐treated soil compared with that in the control (0.1%), and Acaulospora was only detected in the three treated soils. In addition to shaping AM fungal communities, the RH appeared to be the strongest treatment for increasing AM fungal diversity, alkaline phosphatase activity, and glomalin‐related soil protein (GRSP) concentrations, and these parameters were positively correlated (p < .05) with edaphic factors, notably the organic carbon concentration. Furthermore, GRSP could be used as an ecological indicator of AM fungal functioning. This study highlights that the combined application of crop residues and livestock manure could have synergistic effects that help to ameliorate the community structure and diversity of AM fungi in degraded fields.

17468. 题目: Localized pollution impacts on greenhouse gas dynamics in three anthropogenically modified Asian river systems
文章编号: N21051316
期刊: Journal of Geophysical Research: Biogeosciences
作者: Most Shirina Begum, Matthew J. Bogard, David E. Butman, Eliyan Chea, Sanjeev Kumar, Xixi Lu, Omme K. Nayna, Lishan Ran, Jeffrey E. Richey, Shafi M. Tareq, Do Thi Xuan, Ruihong Yu, Ji‐Hyung Park
更新时间: 2021-05-13
摘要: Despite growing research on greenhouse gas (GHG) emissions from inland waters, few systematic efforts have been made to assess the regional‐scale GHG emissions from Asian rivers under increasing anthropogenic stress. We examined factors controlling longitudinal and seasonal variations in the partial pressure of CO2 (pCO2), and CH4 and N2O concentrations in the Ganges, Mekong, and Yellow River by simultaneously measuring gas concentrations and stable C isotopes, and optical properties of dissolved organic matter (DOM) from 2016 to 2019. The levels of pCO2 and CH4 were distinctively higher in polluted tributaries and affected reaches of the Ganges and Mekong than in the Yellow River. The highest levels of N2O were found in the Ganges, followed by the Yellow River and Mekong. Across these basins, dry‐season mean concentrations of CO2, CH4, and N2O were 1.6, 2, and 7 times higher than those measured in the monsoon season, respectively. This seasonality was consistent with that of δ13C‐CO2, while δ13C‐CH4 showed an opposite pattern. GHG concentrations exhibited significant positive relationships with DOM concentrations and optical properties including fluorescence index and protein‐like fluorescence, implying the contribution of anthropogenic, labile DOM to production of GHGs in the polluted reaches. Graphical mixing models of δ13C‐CO2 and δ13C‐CH4 support the stronger impact of wastewater on the Ganges and Mekong than on the Yellow River. The overall results suggest that neglecting localized pollution impacts on GHG emissions from increasingly urbanized river basins can result in a substantial underestimation of global riverine GHG emissions.

17469. 题目: Determining nitrate and sulfate pollution sources and transformations in a coastal aquifer impacted by seawater intrusion—A multi-isotopic approach combined with Self-organizing maps and a Bayesian mixing model
文章编号: N21051315
期刊: Journal of Hazardous Materials
作者: Juan Antonio Torres-Martínez, Abrahan Mora, Jürgen Mahlknecht, Dugin Kaown, Damia Barceló
更新时间: 2021-05-13
摘要: Over the past few decades, the La Paz aquifer system in Baja California Sur, Mexico, has been under severe pressure due to overexploitation for urban water supply and agriculture; this has caused seawater intrusion and deterioration in groundwater quality. Previous studies on the La Paz aquifer have focused mainly on seawater intrusion, resulting in limited information on nitrate and sulfate pollution. Therefore, pollution sources have not yet been identified sufficiently. In this study, an approach combining hydrochemical tools, multi-isotopes (δ2HH2O, δ18OH2O, δ15NNO3, δ18ONO3, δ34SSO4, δ18OSO4), and a Bayesian isotope mixing model was used to estimate the contribution of different nitrate and sulfate sources to groundwater. Results from the MixSIAR model revealed that seawater intrusion and soil-derived sulfates were the predominant sources of groundwater sulfate, with contributions of ∼43.0% (UI90 = 0.29) and ∼42.0% (UI90 = 0.38), respectively. Similarly, soil organic nitrogen (∼72.0%, UI90 = 0.33) and urban sewage (∼26.3%, UI90 = 0.33) were the primary contributors of nitrate pollution in groundwater. The dominant biogeochemical transformation for NO3- was nitrification. Denitrification and sulfate reduction were discarded due to the aerobic conditions in the study area. These results indicate that dual-isotope sulfate analysis combined with MixSIAR models is a powerful tool for estimating the contributions of sulfate sources (including seawater-derived sulfate) in the groundwater of coastal aquifer systems affected by seawater intrusion.

17470. 题目: Distribution of heavy metal resistant bacterial community succession in cow manure biochar amended sheep manure compost
文章编号: N21051314
期刊: Bioresource Technology
作者: Huimin Liu, Yuwen Zhou, Shiyi Qin, Sanjeev Kumar Awasth, Tao Liu, Hong Liu, Zengqiang Zhang, Mukesh Kumar Awasthi
更新时间: 2021-05-13
摘要: The aim of this investigation was to study the effects of cow manure biochar (CMB) on the distribution of heavy metal resistant bacterial (HMRB) community succession during sheep manure (SM) composting. The experiments were conducted with six different ratio of CMB (0%(T1), 2.5%(T2), 5%(T3),7.5%(T4),10%(T5) and 12%(T6)onadryweightbasis) and 0% is used as control. The results showed that the most dominant phylum were Proteobacteria (40.89%-5.65%) and Firmicutes (0.16%-93.18%), and 7.5% CMB mixed with sheep manure for best results. Thus, significant correlation was noticed among the analyzed physicochemical factors, gaseous emission and bacterial phylum in used 7.5-10% CMB applied for SM composting. Overall, the application of biochar increased the diversity of the bacterial community and promoted the degradation of organic matter. In addition, 7.5-10% CMB applied treatments showed greater immobilization of HMRB community succession during SM composting.

17471. 题目: Treatment of old landfill leachate by persulfate enhanced electro-coagulation system: improving organic matters removal and precipitates settling performance
文章编号: N21051313
期刊: Chemical Engineering Journal
作者: Yang Deng, Nan Chen, Weiwu Hu, Haishuang Wang, Peijing Kuang, Fangxin Chen, Chuanping Feng
更新时间: 2021-05-13
摘要: Electro-coagulation process is an alternative method for the treatment of old landfill leachate. However, limited removal of chemical oxygen demand (COD) and long solid-liquid separation times are the key technical problems hindering its practical application. In this study, a persulfate-enhanced electro-coagulation system (PECS) was constructed to improve the removal of COD and shorten the settling time of the flocculation precipitates. Compared with the traditional electro-coagulation process, the PECS can improve the COD removal from 41.1% to 72.6% (60 min reaction and current density of 50 mA/cm2) using activated persulfate oxidation process. The PECS process involves the formation of sulfate and hydroxyl radicals as the main oxidants. The dissolved organic matter in the old landfill leachate mainly consisted of macromolecular humus-like substances. PECS can reduce the aromaticity and the complexity of organic matter, and generated small molecular-weight organic matter, which was helpful in further alleviating the pressure of subsequent treatment of the leachate. The evolution path of precipitates in PECS followed the process of α- FeOOH/Fe2O3·H2O → Fe3O4, which promoted the formation of Fe3O4, improved the precipitation performance, and reduced the volume of precipitates. PECS could improve the degree of degradation of organic matter, increase the removal of COD, and shorten the separation time of precipitates under similar treatment costs to conventional processes. The results of this study provide an important theoretical basis for improving the performance of existing electro-coagulation equipment in practical engineering applications.

17472. 题目: Source, composition, and distributional pattern of branched tetraethers in sediments of northern Chinese marginal seas
文章编号: N21051312
期刊: Organic Geochemistry
作者: Yongsheng Liu, Wenjie Xiao, Jianqiang Wu, Lulu Han, Hongrui Zhang, Yunping Xu
更新时间: 2021-05-13
摘要: Branched glycerol dialkyl glycerol tetraethers (brGDGTs), biomarkers for organic carbon source and paleoenvironment, can be produced in both land and sea. The source assignment is prerequisite for the accurate application of brGDGTs-based indicators. Here, we reported brGDGTs in surface sediments of northern Chinese Marginal Seas (CMS), including the Bohai Sea, Yellow Sea and East China Sea. Two source indicators, ∑IIIa/∑IIa and #ringstetra, have an average of 0.86 ± 0.18 and 0.74 ± 0.08 in the Bohai Sea, 0.61 ± 0.34 and 0.73 ± 0.16 in the East China Sea, and 1.32 ± 0.45 and 0.87 ± 0.12 in the Yellow Sea, suggesting variable contributions of terrestrial and marine-derived brGDGTs in the Bohai Sea and East China Sea, but the predominance of marine in-situ brGDGTs in the Yellow Sea. The distribution of brGDGTs presents a zonal pattern from nearshore to offshore in the Bohai Sea/East China Sea, but a complex and patched pattern in the Yellow Sea. This difference is attributed to different influences of terrestrial brGDGTs from the Yangtze River and Yellow River. However, the branched and isoprenoid tetraether (BIT) index, an indicator for terrestrial organic carbon in marine environments, has low values (an average of < 0.1) in all three marginal seas, demonstrating the limitation of the BIT index in high productive marginal seas. Of those samples containing pure marine derived brGDGTs (∑IIIa/∑IIa ≥ 0.92), significant correlations between ∑IIIa/∑IIa and CBT5ME and between water temperature and MBT′5ME suggest that the production of brGDGTs by marine bacteria is also affected by ambient pH and temperature, although a global calibration is still lacking.

17473. 题目: Understanding the dependence of start-up and stability of aerobic granule on pH from the perspective of adhesion behavior and properties of extracellular polymeric substances
文章编号: N21051311
期刊: Environmental Research
作者: Zhengwen Li, Huiqi Li, Rui Tang, Chunli Wan, Chen Zhang, Xuejun Tan, Xiang Liu
更新时间: 2021-05-13
摘要: The start-up and stability of aerobic granular sludge (AGS) could be greatly influenced by pH variation. The inner core in the aerobic granules provided adhesion sites for microbes by extracellular polymeric substances (EPS) adhesion, the adhesion behavior of EPS and the properties of adhesion layer formed by EPS with pH changes might directly affect the start-up efficiency and stability of AGS. In this study, the adhesion behavior of EPS at an inorganic surface and the viscoelasticity of the EPS adhesion layer with pH variation was investigated by quartz crystal microbalance with dissipation monitoring, and the response of functional groups and intermolecular interactions to pH changes was explored. Based on the interaction energy calculation, it was found that the charge repulsion between substances dominated the interactions between EPS components and between EPS and the surface by regulating protonation and deprotonation of the functional groups of EPS with pH variation. A lower energy barrier between EPS and the surface at a lower pH value could facilitate the adhesion of EPS at the surface, which favored the rapid start-up of AGS. Moreover, the high ratio of both α-helix and intermolecular hydrogen bond at an acid condition could enhance the gel-strength of EPS, which provide AGS the resistance ability against external disturbance. This study revealed the mechanism of the interactions in EPS adhesion process with the variation of pH and provided useful information for a better understanding of the stability of the AGS.

17474. 题目: The adsorption of U(VI) on magnetite, ferrihydrite and goethite
文章编号: N21051310
期刊: Environmental Technology & Innovation
作者: Yun Wang, Jingjing Wang, Ping Li, Haibo Qin, Jianjun Liang, Qiaohui Fan
更新时间: 2021-05-13
摘要: During the long-term disposal of radioactive waste, ferrous waste containers and building materials are tending to corrode to produce a large number of iron oxides. The formed iron oxides would bring significant effects on the diffusion and migration of radionuclides through adsorption and reduction. This study aimed to evaluate the interaction of U(VI) on iron oxides under anaerobic conditions, where goethite, magnetite, and ferrihydrite were used as adsorbents. The results showed that the adsorption of U(VI) on iron oxides was chemical adsorption, and the adsorption capacity of U(VI) on ferrihydrite was much higher than that on goethite and magnetite. Humic acid (HA) promoted the adsorption of U(VI) on iron oxides under acidic conditions, while U(VI) adsorption was inhibited by HA in the neutral to alkaline conditions. The adsorption of U(VI) on iron oxides was an endothermic process, and higher temperature was beneficial for the adsorption. Surface complexation modelling (SCM) fitting revealed that monodentate inner complexes of ≡FeOUO2+ and ≡FeOUO2(OH)0 were mainly formed on the surface of iron oxides. Finally, the reduction of U(VI) to U(IV) on magnetite under anaerobic condition was confirmed by X-ray photoelectron spectroscopy (XPS) and Mössbauer spectroscopy.

17475. 题目: Biochar supported CuFe layered double hydroxide composite as a sustainable adsorbent for efficient removal of anionic azo dye from water
文章编号: N21051309
期刊: Environmental Technology & Innovation
作者: Mukarram Zubair, Hamidi Abdul Aziz, Ihsanullah Ihsanullah, Mohd Azmier Ahmad, Mamdouh A. Al-Harthi
更新时间: 2021-05-13
摘要: This study reports the synthesis of date palm waste-derived biochar (B) supported Cu-Fe layered double hydroxides (CuFe LDH) composite by facile co-precipitation method. The adsorption performance of B-CuFe composite was evaluated for the removal of Eriochrome black T (EBT), as a model anionic azo dye, from the aqueous phase. The B-CuFe composites were characterized by FTIR, XRD, TGA, SEM-EDX and BET technique. Characterization results revealed the synergistic effect of biochar and CuFe-LDH has resulted in substantial improvement in physicochemical characteristics (i.e. surface functionality, surface area and surface morphology) of B-CuFe composite, which promotes rapid and improved adsorption of (EBT) from the solution. The B-CuFe composite with 2.5 g loading of biochar onto CuFe LDH layers showed better adsorption performance than that of other B-CuFe composites The adsorption process of EBT onto B-CuFe composite was well described by the RSM models (with R2=0.964-0.999). Acidic pH (2-5) and higher temperature favored the adsorption of EBT onto B-CuFe composite, and almost (70%–85%) of EBT was removed from the water within the first 15 min. The highest adsorption capacity, 565.32 mg/g of EBT onto B-CuFe composite, was obtained at pH 2.5 and 45 °C. The adsorption mechanism associated with the strong electrostatic and chemical interactions of EBT sulfonated anions (SO3−) with protonated hydroxyl surface groups (-OH2+) of B-CuFe composite. The B-CuFe composite exhibited better EBT removal in the presence of co-existing anions and demonstrated excellent reusability performance (11 % reduction) after five successive cycles. The results demonstrated that the B-CuFe composite showed great potential as a sustainable and cost-effective adsorbent for the purification of dye contaminated water bodies.

17476. 题目: Higher free-living N2 fixation at rock-soil interfaces than topsoils during vegetation recovery in karst soils
文章编号: N21051308
期刊: Soil Biology and Biochemistry
作者: Yuqian Tang, Jing Tian, Xiangzhen Li, Minjie Yao, Shaoqiang Wang, Yakov Kuzyakov, Jennifer A.J. Dungait
更新时间: 2021-05-13
摘要: The widely distributed karst ecosystem in China has experienced rapid deterioration by deforestation and intensive cultivation in the last 50 years. Under the “Grain for Green” program, disturbed croplands were progressively abandoned to restore soil functions and ecosystem services, observed as discrete vegetation recovery phases: cultivated land, abandoned land and secondary forest, and compared to natural primary forest. Karst soils are naturally poor in nitrogen and cessation of nitrogen fertilizer application after abandonment presents an opportunity to explore the reemergence of indigenous soil N2 fixation mechanisms. In this study, we investigated how vegetation recovery affects key soil properties and their relationships with free-living N2 fixation (FLNF) activity and nifH gene abundance, microbial community structure and network interactions at different soil depths from the surface to the rock-soil interface at the bottom of the soil profile. Soil FLNF activity was increased slightly but not significantly after abandonment and was greatest in primary forest soils. High levels of FLNF activity in primary forest soils was facilitated directly by larger total organic carbon to total nitrogen ratios and an altered free-living diazotrophic community composition that was mainly modified by soil moisture content and pH. Higher FLNF was identified at rock-soil interfaces compared to topsoils, which was mainly driven by altered diazotrophic community composition stimulated by increases in soil pH and dissolved organic carbon to available inorganic nitrogen ratios. Diazotrophic network interactions also contributed to variations in FLNF activity, with relatively stable and competitive, while less niche-separated, diazotrophic communities supporting high FLNF activity in primary forest soils, while complex and mutualistic interactions facilitated the high FLNF at rock-soil interfaces. These results suggest that there is considerable and persistent FLNF in degraded karst landscapes at rock-soil interfaces which enables the provision of a vital biological source of nitrogen to overcome the nutrient limitations of karst rock weathering at the bottom of the soil profile.

17477. 题目: Immobilized redox mediators on modified biochar and their role on azo dye biotransformation in anaerobic biological systems: Mechanisms, biodegradation pathway and theoretical calculation
文章编号: N21051307
期刊: Chemical Engineering Journal
作者: Guang-Yuan Wang, Shan-Shan Yang, Jie Ding, Cheng-Xin Chen, Le Zhong, Lan Ding, Ming Ma, Guo-Sheng Sun, Zong-Liang Huang, Nan-Qi Ren
更新时间: 2021-05-13
摘要: In this study, a novel solid-phase redox mediator (RM) was manufactured via immobilizing anthraquinone-2-sulfonate (AQS) onto modified biochar (BC). The RM was used to enhance the anaerobic granular sludge (AGS) driven anaerobic biodegradation of azo dyes. Prepared at the optimal pyrolysis temperature of 550 ℃, the AQS modified BC550 exhibits a higher adsorption capacity of about 12.81% toward AQS compared to that of commercial granular activated carbon (GAC). X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses showed that BC550-AQS contained more redox moieties (quinone and C=O) than GAC-AQS, indicating that the BC550 is suitable as a carrier of immobilized AQS. During the 36-h reaction, incubation of BC550-AQS as the solid-phase RM obviously enhanced the capacity of AGS (BC550-AQS + AGS), evidenced by the maximum percentage of Reactive Red 2 (RR2) decolorization (92.27%), which increased up by 80.55% and 14.48% compared to the controls (BC550-AQS, 17.95%) and (GAC-AQS+AGS, 78.61%). Besides, BC550-AQS exhibits good reusability and a higher RR2 decolorization rate (per AQS dosage) over 15 consecutive cycles. The mechanism of biodegradation pathway of RR2 initiated by BC550-AQS was studied using liquid chromatography-mass spectrometry and chemical computation. Density-functional theory calculations successfully predict that the RR2 biodegradation pathway mainly includes azo bond cleavage and electron attraction with a stronger electron affinity. This work not only proposes a deep insight into the biodegradation pathway of RR2 by employing BC550-AQS in an anaerobic biological system but also develops effective solid-phase RMs for efficient removal of contaminants from wastewaters by biological treatment.

17478. 题目: Globally relevant lessons from a long-term trial series testing universal hypothesis of the impacts of increasing biomass removal on site productivity and nutrient pools
文章编号: N21051306
期刊: Forest Ecology and Management
作者: L.G. Garrett, S.J. Smaill, S.L. Addison, P.W. Clinton
更新时间: 2021-05-13
摘要: It is established that the long-term productivity of planted forests now and into the future requires a consistent supply of nutrients from soil for sustained growth over multiple rotations, and the importance of soil function to other important planted forest ecosystem services such carbon cycling is now increasingly recognised. In addition, advances in analytical techniques have provided capability to investigate the soil biological communities that supports these functions. The New Zealand Long-Term Site Productivity (LTSP) trial series has been a fundamental research infrastructural asset for exploring the impacts of harvest residue and forest floor removal, providing new insights into the sustainability of soil nutrient and organic matter (soil carbon) stocks and the diverse range of soil biological activity that supports many ecosystem level processes essential to continuous forest productivity. This paper provides a globally unique synthesis from a long-term test of a universal hypothesis and discusses how the findings throughout the ~ 30 year lifespan of the trial series have supported the development of knowledge and tools that are leading to changes to forest management practice. Key examples include the development of the Nutrient Balance Model (NuBalM) platform, demonstration of the critical importance of harvest residues and forest floor material at low fertility sites, and new evidence identifying the enduring sensitivity of the soil microbial community to disruption caused by harvesting intensity. Combined, these results have underpinned significant changes in how planted forest soils in New Zealand are managed, in terms of both nutrition and the influence of beneficial soil microbes. Discussion of these outcomes is particularly timely given the increasing global demands on wood and fibre supply, and demonstrates the importance of long-term site productivity trials to the ongoing ability of forest growers and managers to deliver multiple benefits from planted forests. An outlook is provided on what the future might hold in terms of increasing intensification and the implications of multiple rotations over a larger area of forest in the future.

17479. 题目: Adsorption of microcystin-LR by rice straw biochars with different pyrolysis temperatures
文章编号: N21051305
期刊: Environmental Technology & Innovation
作者: Lianxue Wei, Jinfeng Lu
更新时间: 2021-05-13
摘要: Biochars derived from rice straw (RS biochars) at various pyrolysis temperatures (300 °C, 400 °C, 500 °C, 600 °C, and 700 °C) were studied to explore their adsorption ability of microcystin-LR (MC-LR) and to find out the associations between structural properties of different RS biochars and their adsorption capacity. The BET surface area determination was performed RS-700,biochar was found to contain the specific surface area of 360.9 m2g−1, which was significantly larger than others. In addition, with the increase of pyrolysis temperatures, the larger and denser pore canals of RS biochars could be seen through the observation of surface morphologies and microstructures Moreover, the adsorption kinetic and equilibrium models were determined for different RS biochars. For all adsorbents, the adsorption kinetics were well fitted with the pseudo-second-order kinetic model (R2:0.9455-0.9956) and the adsorption equilibrium were well described with Freundlich model (R2>0.9). The removal of MC-LR was positively related to the pyrolysis temperatures of RS biochars. RS-700 biochar exhibited the maximal adsorption capacity of 10.96 μg g−1, which was more than 2 times as much as that of RS-300 biochar. And the adsorption amount of MC-LR increased substantially with the increasing initial concentration of MC-LR. Furthermore, the effect of pH value was also evaluated for the better understanding of adsorption mechanisms.

17480. 题目: Biochar decreased enantioselective uptake of chiral pesticide metalaxyl by lettuce and shifted bacterial community in agricultural soil
文章编号: N21051304
期刊: Journal of Hazardous Materials
作者: Xiangwei You, Fengyue Suo, Shaojing Yin, Xiao Wang, Hao Zheng, Song Fang, Chengsheng Zhang, Fengmin Li, Yiqiang Li
更新时间: 2021-05-13
摘要: A 35-day microcosmic experiment was conducted with lettuce (Lactuca sativa L.) and two metalaxyl (MET) enantiomers (R-MET and S-MET) to understand the roles of biochar in the enantioselective fate of chiral pesticides in soil-plant ecosystems. Wood waste-derived biochar (WBC) amendment effectively decreased the shoot concentrations of R-MET/S-MET and their metabolites R-MET/S-MET acid by 57.7–86.3% and 13.3–32.5%, respectively. The reduced uptake was mainly attributed to the decreased bioavailability of R-MET and S-MET. A lower fraction of R-MET was accumulated by the lettuce in the WBC-amended soils relative to the control, suggesting a decrease in the enantioselective uptake of the chiral pesticide MET in the presence of biochar. Regardless of the WBC amendment, no enantiomerization of MET or MET acid occurred. The application of WBC stimulated soil bacterial diversity, shifted the bacterial community, and enhanced the abundance of pesticide degrading bacteria (e.g., Luteimonas, Methylophilus, and Hydrogenophaga), which were responsible for the enantioselective degradation of MET in the soil. This work expands our understanding of the enantioselective fate of chiral pesticides in the biochar-amended soil ecosystems. These findings can be used to develop biochar-based technologies to remediate soils contaminated with these chiral pesticides to ensure food safety.