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17481. 题目: The regulatory effects of biotic and abiotic factors on soil respiration under different land-use types
文章编号: N21051303
期刊: Ecological Indicators
作者: H.B. Xiao, Z.H. Shi, Z.W. Li, J. Chen, B. Huang, Z.J. Yue, Y.M. Zhan
更新时间: 2021-05-13
摘要: Assessing the impacts of land use on soil respiration (Rs) and its temperature sensitivity (Q10) is of vital significance for understanding regional carbon cycles. In this study, the regulation of Rs and Q10 by soil biotic and abiotic factors under different land-use types, i.e., cropland, apple orchard, abandoned land, Coronilla varia grassland, and Robinia pseudoacacia woodland, were examined in the Luoyugou watershed on the Chinese Loess Plateau. We monitored Rs, soil temperature, and moisture in situ from July to December 2018 and evaluated soil microbial abundance, root biomass, carbon and nitrogen nutrient levels. The results showed that soil organic carbon, total nitrogen, available nitrogen, dissolved organic carbon, and microbial biomass carbon decreased by the following order: grassland > woodland > abandoned land > cropland > orchard. The high amounts of plant residues and the low levels of human disturbance in grassland and woodland contributed to higher soil carbon and nitrogen nutrient levels in these land-use types than in cropland and orchard. Rs decreased from July to December, with soil temperature and moisture being the key explanatory factors. The mean Rs in grassland (3.68 μmol m−2 s−1) and woodland (3.81 μmol m−2 s−1) was significantly higher than that in cropland, orchard, and abandoned land. Q10 ranged from 1.77 to 5.87 across all land-use types, and orchard, abandoned land, grassland, and woodland had Q10 values 1.91, 1.37, 1.47, and 3.32 times higher, respectively, than the Q10 of cropland. The variable importance in the projection (VIP) values from the partial least squares regression model showed that soil temperature (VIP = 1.41), pH (VIP = 1.22), microbial biomass nitrogen (VIP = 1.13), microbial biomass carbon (VIP = 1.12), bacterial abundance (VIP = 1.12), available nitrogen (VIP = 1.01), and soil moisture (VIP = 1.01) were the most important predictors of Rs. Our study suggests that soil temperature and labile organic matter exert stronger impacts on Rs than do microbial abundance and root biomass. Our results contribute to a better understanding of ecosystem carbon cycles.

17482. 题目: Activation of persulfate by magnetic zirconium-doped manganese ferrite for efficient degradation of tetracycline
文章编号: N21051302
期刊: Chemical Engineering Journal
作者: Zhanmeng Liu, Zhimin Gao, Qin Wu
更新时间: 2021-05-13
摘要: Tetracycline (TC) is a typical antibiotic that is eco-toxic and easily causes bacterial resistance, and thus it is necessary to eliminate tetracycline from the water environment. In this study, an innovative TC removal approach was developed by activation of persulfate (PDS) using oxide-based materials fabricated via low-temperature co-precipitation: Zr oxide/MnFe2O4 (ZrO2/MnFe2O4). The effects of Fe/Zr molar ratio, the dose of ZrO2/MnFe2O4 and PDS, initial pH, TC concentration, co-existing anions, natural organic matter on TC degradation were investigated. Under optimal conditions (Fe/Zr = 10, PDS = 6.0 mM, ZrO2/MnFe2O4-10 = 0.20 g/L, and pH = 7.1), the TC degradation efficiency of 85.2% could be achieved after 120 min.Besides, the TOC removal efficiency reached 67.9% (TC = 5.0 mg/L). Besides, the TC degradation efficiency was different extents inhibited by inorganic anions (H2PO4- >HCO3- > NO3- > Cl-) and organic substances (EDTA > HA). Furthermore, the results of quenching experiments, electron paramagnetic resonance (EPR) analysis, and X-ray photoelectron spectroscopy (XPS) spectra analysis demonstrated that three radicals (hydroxyl radicals (·OH), sulfate radicals (SO4·-), and superoxide radicals (O2·-)) contribute to rapid TC decomposition in ZrO2/MnFe2O4-10/PDS system. Particularly, the ZrO2/MnFe2O4-10 exhibited superparamagnetic property and excellent stability, which was conducive to the effective recovery and utilization of the catalyst through the external magnetic field. Based on the degradation products determined by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS), the possible four degradation pathways of TC degradation were proposed in the ZrO2/MnFe2O4-10/PDS system. This study indicates the ZrO2/MnFe2O4 composite is an efficient and environmentally catalyst for PDS oxidation of organic pollutants.

17483. 题目: Operating Bicarbonate-Form versus Chloride-Form Ion Exchange Resins without Regeneration for Natural Organic Matter Removal
文章编号: N21051301
期刊: ACS ES&T Water
作者: Zhen Liu, Isabelle Papineau, Madjid Mohseni, Sigrid Peldszus, Pierre R. Bérubé, Sébastien Sauvé, Benoit Barbeau
更新时间: 2021-05-13
摘要: Ion exchange (IX) is a promising drinking water treatment process for natural organic matter (NOM) removal. However, standard IX processes require frequent regenerations with concentrated NaCl solution, producing a brine that requires costly and complicated disposal methods. To alleviate the burden of IX brine, we previously proposed operating IX with infrequent regeneration to favor biomass development on the resins and thus benefit NOM removal through biomass contribution, a process referred to as biological ion exchange (BIEX). The objective of the present study is to evaluate the performance of BIEX filtration for NOM removal from primary IX to complete exhaustion using bicarbonate-form and chloride-form IX resins. Parallel pilot-scale bicarbonate-form and chloride-form BIEX were fed with surface water (dissolved organic carbon (DOC) = 7 mg C/L) for 9 months without regeneration. The results demonstrated that bicarbonate-form BIEX achieved a marginally lower DOC removal (median: 49% vs 53%), a higher biodegradable DOC (BDOC) removal (average: 50% vs 33%) and a similar disinfection byproduct precursor removal compared to chloride-form BIEX. Overall, BIEX filtration using bicarbonate-form and chloride-form IX resins offers a similar NOM removal efficiency and eases spent brine management.

17484. 题目: A critical assessment on the short-term response of microbial relative composition in a mine tailings soil amended with biochar and manure compost
文章编号: N21051218
期刊: Journal of Hazardous Materials
作者: Yolanda Risueño, César Petri, Héctor M. Conesa
更新时间: 2021-05-12
摘要: Phytomanagement of tailings requires the use of soil conditioners to favour plant establishment, but their benefits on soil microbial composition need to be assessed. The goal of this work was to evaluate the effect of two organic amendments, manure compost and biochar, on soil bacterial and fungal composition at metallic mine tailings. The addition of compost caused stronger effects in most of soil parameters and microbial composition than biochar, especially at the initial stage of the experiment. However, the higher dependence on labile organic carbon for some bacterial groups at the treatments containing compost determined their decay along time (Flavobacteriales, Sphingobacteriales) and the appearance of other taxa more dependent on recalcitrant organic matter (Xanthomonadales, Myxococcales). Biochar favoured bacterial decomposers (Actinomycetales) specialized in high lignin and other recalcitrant carbon compounds. Unlike bacteria, only a few fungal orders increased their relative abundances in the treatments containing compost (Sordariales and Microascales) while the rest showed a decrease or remained unaltered. The mix biochar-compost may result the best option to support a more diverse microbial population in terms of soil functionality that is able to decompose both labile and recalcitrant carbon compounds. This may favour the resilience of the system against environmental stressors.

17485. 题目: Mineral stabilization of soil carbon is suppressed by live roots, outweighing influences from litter quality or quantity
文章编号: N21051217
期刊: Biogeochemistry
作者: Derek Pierson, Lucas Evans, Kamron Kayhani, Richard D. Bowden, Knute Nadelhoffer, Myrna Simpson, Kate Lajtha
更新时间: 2021-05-12
摘要: Conserving soil carbon (C) and harnessing the potential for soil C sequestration requires an improved understanding of the processes through which organic material accumulates in soil. Currently, competing hypotheses exist regarding the dominant mechanisms that control soil C accumulation and transfers to mineral-associated pools. Long-standing hypotheses rely upon an assumed strong relationship between the quantity of organic inputs and soil C accumulation, while more recent hypotheses have shifted the focus towards the more complex controls of root activity, microbial processing and priming, and organo-mineral complexation. The Detrital Input and Removal Treatment (DIRT) experiment can test these competing hypotheses through field manipulations of detrital inputs. After 20 years of detrital manipulations in the wet, temperate forest of the H.J. Andrews Experimental Station, we found that with the termination of live root activity, the significant influx of dead root material and absence of soil priming by roots led to decreases in particulate organic matter (POM), but increases in stable mineral associated organic matter (MAOM). This suggests that soil mineral particles in undisturbed soils are not saturated with C in the presence of live roots and that pools of MAOM are sensitive to the balance between microbial-induced stabilization and microbial-induced priming and destabilization. Twenty years of aboveground litter removal did not change bulk soil C stocks or pools. Soil C stabilization did not increase in response to increases in high quality litter inputs, in contrast to recent theory, but in accordance with other empirical results. In contrast, increases in low quality wood litter led to a large increase in bulk soil C, with gains over 20 years confined to increases in POM. These findings offer insight into the pathways controlling soil C contents and provide potential explanations for the often-limited potential to increase mineral associated soil C in many vegetated soils and observed buffered responses of soil C stocks to disturbances such as drought, fire, and timber harvest.

17486. 题目: Up-concentration processes of organics for municipal wastewater treatment: New trends in separation
文章编号: N21051216
期刊: Science of The Total Environment
作者: Conghui He, Kaijun Wang, Kuo Fang, Hui Gong, Zhengyu Jin, Qiuhang He, Qi Wang
更新时间: 2021-05-12
摘要: Carbon neutrality is a pressing goal for the whole society. Over 20% of municipality electrical energy on public utilities was consumed by the operation of wastewater treatment plants (WWTPs). Up-concentration of organic matters and maximum energy recovery is essential for a more sophisticated municipal wastewater management. Chemical coagulation and biological adsorption have been used to achieve efficient carbon capture, while separation is an overlooked step. It may lead to poor effluent quality, as well as consume most of the time and volume. The introduction of new driving forces, such as pressure and magnetism, significantly improved the retention rate and speed, respectively. In this paper, recent works were comprehensively reviewed and a horizontal comparison was conducted from aspects of separation speed, retention rate, concentrate characteristics and economic costs. This review also discussed the selection of technologies under different conditions. Finally, the practical application, fouling mitigation with considering the value of the concentrate, identification of unique concentrate characteristics, and the establishment of an evaluation system was suggested as core issues for future researches. This review will promote the development of an energy-efficient wastewater treatment system with up-concentration processes.

17487. 题目: Comparing arsenic(V) adsorption by two types of red soil weathered from granite and sandstone in Hunan, China
文章编号: N21051215
期刊: Environmental Earth Sciences
作者: Hongwei Chen, Shengyu Lin, Zhengzui Li, Lue Zhao, Runchu Wei, Feng Sheng
更新时间: 2021-05-12
摘要: Different soils have large differences in efficiencies and mechanisms in arsenic (As) adsorption, due to the dissimilarities of soil minerals, organic matter (OM) and physiochemical properties. To understand the differences of As adsorption resulting from these differences among soils, the red soil weathered from granite (RS-G) and sandstone (RS-S) were employed to comparatively study the minerals, OM, physicochemical properties, and the isotherms and kinetics of As(V) adsorption. The soil samples were collected at 0–20 cm depth on the top of the mother rocks in Dingziwan and Yuelu Mountain, Changsha, Hunan province in China. The soil minerals were characterized by X-ray powder diffraction (XRD). The specific surface area (SSA) of the soil samples was determined using a BET Analyzer with nitrogen and multi-point analysis after degassing overnight at 100 °C. The cation exchange capacity (CEC) was determined by the method of ammonium acetate centrifugal exchange, and the OM, pH, and point of zero charge (pHPZC) were measured using improved potassium dichromate volumetric weight method, titration, and potentiometric titration method, respectively. The As(V) in the solution was measured by graphite furnace atomic absorption spectrometry (GFAAS). RS-G contains more clay minerals and iron (hydr)oxides, and less quartz than RS-S by 25.31%, 111.69%, and − 22.39%, respectively. There are similar SSA, CEC, and OM content, but different pHpzc and OM sources between the two soil types. The adsorption experiments reveal (1) the As(V) removal efficiency drops rapidly as the initial As(V) concentration is greater than 4.0 mg/L for RS-G and 8.0 mg/L for RS-S, and that of RS-S decreases more slowly as the As(V) concentration increasing from 4.0 to 20.0 mg/L, (2) the As(V) removal efficiency decreases rapidly as the pH is larger than 8.0 for RS-G and 7.0 for RS-S, and (3) the time reaching equilibrium is 120 min for RS-G and 180 min for RS-S, and their kinetics show two and three stages adsorption processes, respectively. The higher mineral content and pHPZC are the main causes for RS-G showing higher As(V) removal efficiency, shorter time to reach equilibrium, and wider pH range for As(V) adsorption. The young OM in RS-G may be responsible for the rapid decrease of As(V) removal efficiency as the As(V) concentration larger than 4.0 mg/L. Comparatively, the RS-G is more efficient for As(V) adsorption, and is more potential for groundwater protection from As contamination.

17488. 题目: Humic acid inhibits colony formation of the cyanobacterium Microcystis at high level of iron
文章编号: N21051214
期刊: Chemosphere
作者: Xiao Ma, Ming Li, Enli Jiang, Baozhu Pan, Li Gao
更新时间: 2021-05-12
摘要: Colony formation is a key process for the occurrence of Microcystis blooms. In order to inhibit colony formation of Microcystis at high level of iron using humic acid, unicellular Microcystis aeruginosa was cultivated in laboratory treated with varying concentrations of iron and humic acid. Our results showed that the extracellular polysaccharides (EPS) content and average colony size increased from 0.57 pg cells-1 and 4.0 μm to 0.93 pg cells-1 and 26.1 μm, respectively, while iron concentration increased from 0.68 mg L-1 to 6.8 mg L-1, suggesting that high level of iron stimulated EPS secretion and induced unicellular Microcystis to form colonies. Transcriptome analysis showed that two genes described as glycosyltransferases (BH695-2217 and BH695-3696) were significantly up-regulated while EPS content increased with increasing iron concentration indicating that iron may regulate the expression of genes involved in polysaccharide synthesis. When treated with 10 mg C L-1 humic acid at high level of iron, the EPS content and average colony size decreased by 35.5% and 56.3%, respectively, revealing that humic acid inhibited EPS secretion under high level of iron condition, and ultimately inhibited colony formation of Microcystis. Our results suggested that humic acid could be used as an agentia inhibiting large colony formation of Microcystis and thereby reducing the occurrence of Microcystis blooms.

17489. 题目: Cadmium Isotope Fractionation during Complexation with Humic Acid
文章编号: N21051213
期刊: Environmental Science & Technology
作者: Gildas Ratié, Vladislav Chrastný, Damien Guinoiseau, Rémi Marsac, Zuzana Vaňková, Michael Komárek
更新时间: 2021-05-12
摘要: Cadmium (Cd) isotopes are known to fractionate during complexation with various environmentally relevant surfaces and ligands. Our results, which were obtained using (i) batch experiments at different Cd concentrations, ionic strengths, and pH values, (ii) modeling, and (iii) infrared and X-ray absorption spectroscopies, highlight the preferential enrichment of light Cd isotopes bound to humic acid (HA), leaving the heavier Cd pool preferentially in solution (Δ114/110CdHA–Cd(aq) of −0.15 ± 0.01‰). At high ionic strengths, Cd isotope fractionation mainly depends on its complexation with carboxylic sites. Outer-sphere complexation occurs at equilibrium together with inner-sphere complexation as well as with the change of the first Cd coordination and its hydration complexes in solution. At low ionic strengths, nonspecific Cd binding induced by electrostatic attractions plays a dominant role and promotes Cd isotope fractionation during complexation. This significant outcome elucidates the mechanisms involved in HA–Cd interactions. The results can be used during (i) fingerprinting the available Cd in soil solution after its complexation with solid or soluble natural organic matter and (ii) evaluating the contribution of Cd complexation with organic ligands and phytoplankton-derived debris versus Cd assimilation by phytoplankton in seawater.

17490. 题目: Preparation of biochar-interpenetrated iron-alginate hydrogel as a pH-independent sorbent for removal of Cr(VI) and Pb(II)
文章编号: N21051212
期刊: Environmental Pollution
作者: Chenhao Zhao, Linlin Hu, Changai Zhang, Shengsen Wang, Xiaozhi Wang, Zhongyang Huo
更新时间: 2021-05-12
摘要: Herein, a pH-independent interpenetrating polymeric networks (Fe-SA-C) were fabricated from graphitic biochar (BC) and iron-alginate hydrogel (Fe-SA) for removal of Cr(VI) and Pb(II) in aqueous solution. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and scanning electron microscope (SEM) results demonstrated that graphitic BC interpenetration increased surface porosity and distorted surfaces of Fe-SA, which boosted availability of hydroxyl (-OH) group. Fe3+ as a cross-linking agent of the alginate endowed Fe-SA-C with positive surfaces (positive zeta potential) and excellent pH buffering capacity, while excessive Fe3+ was soldered on Fe-SA-C matrix as FeO(OH) and Fe2O3. Cr(VI) removal at pH of 3 by Fe-SA-C (20.3 mg g-1) were 30.3% and 410.6% greater than that by Fe-SA and BC, respectively. Fe-SA-C exhibited minor pH dependence over pH range of 2-7 towards Cr(VI) retention. Greater zeta potential of Fe-SA-C over Fe-SA conferred a better electrostatic attraction with Cr(VI). FTIR and XPS of spent sorbents confirmed the reduction accounted for 98.5% for Cr(VI) removal mainly due to participation of -OH. Cr(VI) reduction was further favored by conductive carbon matrix in Fe-SA-C, evidenced by more negative Tafel corrosion potential. Reductively formed Cr(III) was subsequently complexed with carboxylic groups originating from oxidation of -OH. Thus, Cr(VI) removal invoked electrostatic attraction, reduction, and surface complexation mechanisms. Pb(II) removal with excellent pH independence was mainly ascribed to surface complexation and possible precipitation. Thus, the functionalized, conductive, and positively-charged Fe-SA-C extended its applicability for Cr(VI) and Pb(II) removal from aqueous solutions in a wide pH range. This research could expand the application of hydrogel materials for removal of both cationic and anionic heavy metals in solutions over an extended pH range.

17491. 题目: Predicting the Ratio of Nitrification to Immobilization to Reflect the Potential Risk of Nitrogen Loss Worldwide
文章编号: N21051211
期刊: Environmental Science & Technology
作者: Yushu Zhang, Baobao Pan, Shu Kee Lam, Edith Bai, Pengfu Hou, Deli Chen
更新时间: 2021-05-12
摘要: Nitrification and immobilization compete for soil ammonium (NH4+); the relative dominance of these two processes has been suggested to reflect the potential risk of nitrogen loss from soils. Here, we compiled a database and developed a stochastic gradient boosting model to predict the global potential risk of nitrogen loss based on the ratio of nitrification to immobilization (N/I). We then conducted a meta-analysis to evaluate the effects of common management practices on the N/I ratio. The results showed that the soil N/I ratio varied with climate zones and land use. Soil total carbon, total nitrogen, pH, fertilizer nitrogen application rate, mean annual temperature, and mean annual precipitation are important factors of soil N/I ratio. Meta-analysis indicated that biochar, straw, and nitrification inhibitor application reduced the soil N/I ratio by 67, 64, and 78%, respectively. Returning plantation to forest and cropland to grassland decreased the soil N/I ratio by 88 and 45%, respectively. However, fertilizer nitrogen application increased the soil N/I ratio by 92%. Our study showed that the soil N/I ratio and its associated risk level of nitrogen loss were highly related to long-term soil and environmental properties with high spatial heterogeneity.

17492. 题目: Rhodamine B Dye Adsorption onto Biochar from Olive Biomass Waste
文章编号: N21051210
期刊: Water, Air, & Soil Pollution
作者: Isadora Iensen Albanio, Pâmela Cristine Ladwig Muraro, William Leonardo da Silva
更新时间: 2021-05-12
摘要: Olive biomass waste (Olea europaea L.) is a by-product of vegetable oil extraction processing produced in ever-increasing quantities, becoming an environmental liability when not destination or treated correctly. Thus, the work aimed to study the application of olive biomass waste to preparation of adsorbent material (biochar) to rhodamine B (RhB) dye removal. For the preparation of the biochar, activation/carbonization process was used, where for chemical activation, the ZnCl2 was used as activating reagent, in the proportion of 1:2 w/w, and for the carbonization, used a heating rate of 10 °C min−1 to 600 °C for 240 min. Materials were characterized by X-ray diffraction (XRD), zeta potential (ZP), and Fourier transform infrared spectroscopy (FTIR), and its adsorption potential to remove RhB dye from aqueous media was verified, through kinetic, equilibrium, and thermodynamic study. About kinetic adsorption, the pseudo-first-order model showed satisfactorily represented. Moreover, Freundlich model was suitable to represent the adsorption equilibrium of the RhB dye. The maximum value for adsorption capacity was 263.71 mg g–1, and the adsorption process was thermodynamically spontaneous, favorable, and endothermic. Therefore, the olive biomass waste can be considered a potential adsorbent for the wastewater treatment with dyes, mainly.

17493. 题目: Markers of lipid oxidation and inflammation in bronchial cells exposed to complete gasoline emissions and their organic extracts
文章编号: N21051209
期刊: Chemosphere
作者: Pavel Rossner, Tereza Cervena, Michal Vojtisek-Lom, Jiri Neca, Miroslav Ciganek, Kristyna Vrbova, Antonin Ambroz, Zuzana Novakova, Fatima Elzeinova, Michal Sima, Zuzana Simova, Vladimir Holan, Vit Beranek, Martin Pechout, David Macoun, Andrea Rossnerova, Jan Topinka
更新时间: 2021-05-12
摘要: Road traffic emissions consist of gaseous components, particles of various sizes, and chemical compounds that are bound to them. Exposure to vehicle emissions is implicated in the etiology of inflammatory respiratory disorders. We investigated the inflammation-related markers in human bronchial epithelial cells (BEAS-2B) and a 3D model of the human airways (MucilAirTM), after exposure to complete emissions and extractable organic matter (EOM) from particles generated by ordinary gasoline (E5), and a gasoline-ethanol blend (E20; ethanol content 20% v/v). The production of 22 lipid oxidation products (derivatives of linoleic and arachidonic acid, AA) and 45 inflammatory molecules (cytokines, chemokines, growth factors) was assessed after days 1 and 5 of exposure, using LC-MS/MS and a multiplex immunoassay, respectively. The response observed in MucilAirTM exposed to E5 gasoline emissions, characterized by elevated levels of pro-inflammatory AA metabolites (prostaglandins) and inflammatory markers, was the most pronounced. E20 EOM exposure was associated with increased levels of AA metabolites with anti-inflammatory effects in this cell model. The exposure of BEAS-2B cells to complete emissions reduced lipid oxidation, while E20 EOM tended to increase concentrations of AA metabolite and chemokine production; the impacts on other inflammatory markers were limited. In summary, complete E5 emission exposure of MucilAirTM induces the processes associated with the pro-inflammatory response. This observation highlights the potential negative health impacts of ordinary gasoline, while the effects of alternative fuel are relatively weak.

17494. 题目: Macromolecular Characterization of Compound Selectivity for Oxidation and Oxidative Alterations of Dissolved Organic Matter by Manganese Oxide
文章编号: N21051208
期刊: Environmental Science & Technology
作者: Jianchao Zhang, Amy M. McKenna, Mengqiang Zhu
更新时间: 2021-05-12
摘要: Manganese (Mn) oxides can oxidize dissolved organic matter (DOM) and alter its chemical properties and microbial degradability, but the compound selectivity for oxidation and oxidative alterations remain to be determined. We applied ultrahigh mass spectrometry to catalog the macromolecular composition of Suwannee River fulvic acid (SRFA) before and after oxidation by a Mn oxide (δ-MnO2) at pH 4 or 6. Polycyclic aromatic hydrocarbons, polyphenols, and carbohydrates were more reactive in reducing δ-MnO2 than highly unsaturated and phenolic (HuPh) compounds and aliphatics, but highly abundant HuPh contributed the most (∼50%) to the overall reduction of δ-MnO2. On average, oxidized species had higher molecular weights, aromaticity, carbon unsaturation degree, nominal oxidation state of carbon, and oxygen and nitrogen contents but were lower in hydrogen content compared to unoxidized species. The oxidation decreased these molecular indices and oxygen and nitrogen contents but increased the hydrogen content, with stronger changes at the lower pH. This DOM oxidation on polar mineral surfaces was more selective but shared similar selectivity rules to adsorption. The abiotic oxidation resembles microbial oxidative degradation of organic matter, and Mn oxide–oxidizable carbon may be a useful index for detection and identification of labile organic carbon.

17495. 题目: Perfluorooctane sulfonate decomposition by a high photon flux UV/SO32−/N2 system: kinetics and influence factors
文章编号: N21051207
期刊: Water, Air, & Soil Pollution
作者: Xiao-Bao Gong, Zong-Wen He
更新时间: 2021-05-12
摘要: Hydrated electron (eaq−) induced reduction processes are promising for reductive decomposition of recalcitrant organic pollutants, such as perfluorooctane sulfonate (PFOS). In this work, effective defluorination of PFOS by eaq− was conducted in sulfite solution under UV irradiation. Results show that the defluorination efficiency of PFOS followed the order of UV/SO32−/N2 > UV/SO32−/air > UV/SO32−/O2 > UV/N2 > SO32−/N2, which agreed well with the trend of eaq− generation measured by using resazurin as a fluorogenic probe. Under the conditions of pH 9.0, 20 μM PFOS, 10 mM SO32−, 25 °C, and 150 min of reaction time, the decomposition and defluorination efficiencies of PFOS were 98.6 and 45.3%, respectively. The defluorination of PFOS was enhanced by increasing sulfite concentration (5–40 mM), reaction temperature (20–40 °C), or solution pH (pH 7.0–11.0). PFOS defluorination followed the parallel exponential kinetics model, wherein the fast and slow exponential processes were assigned to the decomposition of branched and linear PFOS, respectively. Accompanying PFOS reduction, short-chain perfluorocarboxylic acids were detected and identified. This suggests that eaq−-induced decomposition pathway of PFOS involved defluorination, desulfonation, and centermost C–C bond scission in the UV/SO32−/N2 photolysis system. Humic acid slightly inhibited PFOS defluorination, whereas Cl− and HCO3− showed negligible effect.

17496. 题目: Effects of different tillage and fertilization management practices on soil organic carbon and aggregates under the rice–wheat rotation system
文章编号: N21051206
期刊: Soil and Tillage Research
作者: Zhanhui Zhao, Songfeng Gao, Chunyang Lu, Xiaoyu LI, Fang Li, Tingyun Wang
更新时间: 2021-05-12
摘要: Studying the impact of tillage and fertilization on soil organic carbon (SOC) content and aggregate is essential to define better strategies for improving soil structure and SOC sequestration. A field experiment was conducted for 9 years to investigate effects of different tillage and fertilization management practices on SOC and its active fractions [labile organic carbon (LOC), dissolved organic carbon (DOC) and microbial biomass carbon (MBC)] within the bulk soil and in soil aggregates under rice (Oryza sativa L.)–wheat (Triticum aestivum L.)-based cropping systems. Five treatments were included: conventional tillage with no fertilizer (CT), conventional tillage with chemical fertilizer (CTFR), reduced tillage with chemical fertilizer (RTFR), conventional tillage with organic manure (CTOM), and reduced tillage with organic manure (RTOM). The results showed that the organic manured plots (CTOM and RTOM) significantly increased the concentrations of SOC and active carbon fractions (LOC, DOC and MBC) within the bulk soil and soil macroaggregates, and increased the mass proportion of macroaggregates (>250 μm) compared with chemical fertilizer treatments (CTFR and RTFR) or CT. The highest SOC concentration and macroaggregates (>250 μm) were observed in CTOM. The increased SOC, especially active carbon fractions, was mainly concentrated in soil macroaggregates (>250 μm). Soil aggregates were dominated by macroaggregates (>250 μm), which had higher MBC and lower PAOC (the percentage of slow plus passive carbon fractions) after 9 years of RTOM treatment than after CT or CRFR treatment. The results indicated that RTOM played a positive role in promoting the formation of the soil macroaggregate structure. By studying the responses of SOC and water-stable aggregate contents to different tillage and fertilization managements, the continual application of organic manure may be feasible and the periodic organic manure addition may be combined with reduced tillage practice to produce an integrated soil management strategy for the paddy–upland rotation region in Middle China.

17497. 题目: Estuarine benthic nitrate reduction rates: Potential role of microalgae?
文章编号: N21051205
期刊: Estuarine, Coastal and Shelf Science
作者: Anniet M. Laverman, Jérôme Morelle, Céline Roose-Amsaleg, Alexandrine Pannard
更新时间: 2021-05-12
摘要: The ecological functioning of the Seine estuary is strongly affected by the input of nitrogen, especially in the form of nitrate, which contributes to the eutrophication of the Seine Bight (France). Elimination of nitrate by benthic denitrification in riparian zones or adjacent wetlands could significantly improve the water quality of the Seine estuary. The goal of this study was to investigate the potential for denitrification and the factors affecting these rates. To this end, we measured nitrate reduction and ammonium production rates using flow-through reactors in contrasted sediments collected along the Seine Estuary. Sediment and organic carbon characteristics (organic C, Corg:N ratio, bioavailable carbon, extracellular polymeric substances (EPS), chlorophyll a and phaeopigments and abundance of nitrogen transforming microorganisms were determined and related to the potential nitrate reduction rates. Nitrate reduction rates showed a large spatial and seasonal variation and showed a significant correlation with sediment phaeopigments, whereas overall microbial activity (ammonium production rates) were highly correlated to chlorophyll a and EPS fractions. Surprisingly, bacterial abundance was not correlated to nitrate reduction nor to ammonium production rates. The presence of microalgae appears to be an important driver for nitrate reduction rates in these riparian sediments and seems to have fueled the benthic nitrate reducing activity.

17498. 题目: Anaerobic digestion of waste activated sludge using dynamic membrane at varying substrate concentration reveals new insight towards methanogenic pathway and biofilm formation
文章编号: N21051204
期刊: Chemical Engineering Journal
作者: Roent Dune A. Cayetano, Gi-Beom Kim, Jong-Hun Park, Min-Jae Lee, Sang-Hyoun Kim
更新时间: 2021-05-12
摘要: Biomass retention through the dynamic membrane (DM) proved beneficial to the stable performance of AnDMBR treating waste activated sludge without prior pretreatment. The highest average methane production rate of 1.04 L-CH4/L/d was achieved at a feed concentration of 100 g-COD/L and an organic loading rate of 6.25 g-COD/L-d. Increasing substrate concentration resulted in archaeal population shift from a mixed acetate/H2 utilizing methanogens (Methanosarcinales) to strict H2 utilizing methanogens (Methanobacteriales). Predicted functional gene analysis also confirmed hydrogenotrophic encoding genes became dominant in methanogenic pathways at higher feed concentration. The occurrence of glycosyltransferase encoding genes has substantiated the role of EPS towards DM layer (biofilm) formation which could retain essential microorganisms and achieve steady sludge treatment performance at the high organic loading rate. Moreover, increase in average particle size distribution may suggest the presence of microbial aggregates which also helped in establishing the DM layer. This study shows a promising potential of high-rate treatment of WAS using an AnDMBR system and provides new insights regarding biofilm (DM layer) development.

17499. 题目: Dynamic interactions at the mineral–organic matter interface
文章编号: N21051203
期刊: Nature Reviews Earth & Environment
作者: Markus Kleber, Ian C. Bourg, Elizabeth K. Coward, Colleen M. Hansel, Satish C. B. Myneni, Naoise Nunan
更新时间: 2021-05-12
摘要: Minerals are widely assumed to protect organic matter (OM) from degradation in the environment, promoting the persistence of carbon in soil and sediments. In this Review, we describe the mechanisms and processes operating at the mineral–organic interface as they relate to OM transformation dynamics. A broad set of interactions occur, with minerals adsorbing organic compounds to their surfaces and/or acting as catalysts for organic reactions. Minerals can serve as redox partners for OM through direct electron transfer or by generating reactive oxygen species, which then oxidize OM. Finally, the compartmentalization of soil and sediment by minerals creates unique microsites that host diverse microbial communities. Acknowledgement of this multiplicity of interactions suggests that the general assumption that the mineral matrix provides a protective function for OM is overly simplistic. Future work must recognize adsorption as a condition for further reactions instead of as a final destination for organic adsorbates, and should consider the spatial and functional complexity that is characteristic of the environments where mineral–OM interactions are observed.

17500. 题目: Mesopore-rich badam-shell biochar for efficient adsorption of Cr(VI) from aqueous solution
文章编号: N21051202
期刊: Journal of Environmental Chemical Engineering
作者: Xiuxiu Jia, Yunqiu Zhang, Zhuang He, Fengqin Chang, Hucai Zhang, Thomas Wågberg, Guangzhi Hu
更新时间: 2021-05-12
摘要: Cr(VI) is a common pollutant in wastewater and many previous studies using biochar-based materials as adsorbents for their well adsorption performance. However, the preparations of some biochars are complex, uneconomical, and with a poor reusability, which set limit on their practical application. Here, a mesoporous-rich biochar-based Cr(VI) adsorbent was easily prepared by pyrolyzing the badam-shell that in situ activated by concentrated phosphoric acid (H3PO4), with the aim of improving the removal effect of Cr(VI) in an aqueous solution. The partition coefficient (PC) was used to compare the performance of adsorbents more comprehensively, and the maximal PC value of the activated badam-shell biochar (ABSB) was 978.8Lg-1. In addition, its maximum adsorption capacity was 276.6mgg-1. ABSB has a superior removal effect on the relatively low concentration of Cr(VI) (≤ 50mgL-1), and residual Cr(VI) can meet the maximum emission standard (< 0.5mgL-1) of industrial wastewater. The specific surface area of ABSB (1359.5 m2 g-1) was approximately four times that of pristine badam-shell biochar (BSB) (371.87 m2 g-1). The adsorption mechanisms involved were redox, complexation, electrostatic attraction and hydrogen bonding. The removal rate of Cr(VI) on ABSB remained at 81.6% after six cycles of adsorption–desorption. In a word, our study provides a simple, economic, and environmental method in fabricating the new adsorbent, which is highly promising and will not cause secondary pollution.