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17521. 题目: Preparation and characterization of biochar derived from co-pyrolysis of Enteromorpha prolifera and corn straw and its potential as a soil amendment
文章编号: N21072114
期刊: Science of The Total Environment
作者: Fengyue Suo, Xiangwei You, Shaojing Yin, Haiyun Wu, Chengsheng Zhang, Xueyang Yu, Ruixue Sun, Yiqiang Li
更新时间: 2021-07-21
摘要: Single biomass feedstock approach may not meet the requirements for developing biochar with desired characteristics for use as soil amendment. In this study, biochars were prepared by co-pyrolysis of nutrients-rich Enteromorpha prolifera and lignocellulose-rich corn straw (CPECs) at different mass ratios (3:7, 1:1, and 7:3). CPECs presented more water-soluble N/P content than corn straw biochar, and exhibited larger surface area, low Na content, and slower release rate than Enteromorpha prolifera biochar. The modification in physicochemical and properties of CPECs enhanced its potential application as a soil amendment. A pot experiment showed that CPECs derived from co-pyrolysis of appropriate ratios of Enteromorpha prolifera and corn straw (1:1, 7:3) significantly increased the biomass of cherry tomato plant by 64.05%, 40.03% and 81.88%, 55.25%, when compared with corn straw biochar and Enteromorpha prolifera biochar, respectively. The positive effects of CPECs were primarily attributed to improved soil properties (e.g., water holding capacity, soil organic matter, pH, soil nutrients content) and increased total N/P uptake by plants. Thus, the results of this work study could help to develop “designer” biochars by co-pyrolysis for use as amendments for soil with multiple requirements.

17522. 题目: Research of the replacement of dichromate with depressants mixture in the separation of copper-lead sulfides by flotation
文章编号: N21072113
期刊: Separation and Purification Technology
作者: Fen Jiao, Yanfang Cui, Daowei Wang, Chenqiang Hu
更新时间: 2021-07-21
摘要: To reduce the environmental impact caused by highly toxic dichromate in flotation separation of copper-lead sulfide, the replacement of dichromate with depressants mixture (humic substance and hydrogen peroxide) was investigated in this paper. The single mineral flotation and the mixed binary minerals experiment at pH 6.5 showed that combined depressants could be efficient in separating galena from chalcopyrite and achieve a lead concentrate comparable to conventional method using dichromate as typical depressant. The contact angle measurement and atomic force microscopy (AFM) imaging indicated that, for the same concentration of sodium humate, the treatment by hydrogen peroxide could increase surface wettability and largely enhance chemical adsorption of humate on galena surface. Ion dissolution tests and adsorption tests indicated that the hydrogen peroxide can accelerate dissolution of galena lattice and the hydrogen peroxide or Pb2+ could promote the adsorption of NaHA on the surface of galena.

17523. 题目: Removal of contaminants of emerging concern from multicomponent systems using carbon dioxide activated biochar from lignocellulosic feedstocks
文章编号: N21072112
期刊: Bioresource Technology
作者: Ivan Kozyatnyk, Pierre Oesterle, Christian Wurzer, Ondřej Mašek, Stina Jansson
更新时间: 2021-07-21
摘要: Adsorption of six contaminants of emerging concern (CECs) – caffeine, chloramphenicol, carbamazepine, bisphenol A, diclofenac, and triclosan – from a multicomponent solution was studied using activated biochars obtained from three lignocellulosic feedstocks: wheat straw, softwood, and peach stones. Structural parameters related to the porosity and ash content of activated biochar and the hydrophobic properties of the CECs were found to influence the adsorption efficiency. For straw and softwood biochar, activation resulted in a more developed mesoporosity, whereas activation of peach stone biochar increased only the microporosity. The most hydrophobic CECs studied, caffeine and chloramphenicol, displayed the highest adsorption (22.8 and 11.3 mg g-1) onto activated wheat straw biochar which had the highest ash content of the studied adsorbents (20 wt%). Adsorption of bisphenol A and triclosan, both relatively hydrophobic substances, was highest (31.6 and 30.2 mg g-1) onto activated biochar from softwood, which displayed a well-developed mesoporosity and low ash content.

17524. 题目: Pig carcass-derived biochar material cause contradictory effects on arsenic mobilization in a contaminated paddy soil under fluctuating controlled redox conditions
文章编号: N21072111
期刊: Journal of Hazardous Materials
作者: Xing Yang, Marvin Hinzmann, He Pan, Jianxu Wang, Nanthi Bolan, Daniel C.W. Tsang, Yong Sik Ok, Shan-Li Wang, Sabry M. Shaheen, Hailong Wang, Jörg Rinklebe
更新时间: 2021-07-21
摘要: Contamination of paddy soils by the hazardous arsenic (As) is of great concern for human health the environment. The impact of animal-derived biochar on As mobilization under fluctuating redox conditions in paddy soils has not been studied. Consequently, we investigated the effects of pig carcass-derived biochar (PB) on As (im)mobilization in a contaminated paddy soil under controlled redox potential (Eh) using a biogeochemical microcosm-setup. The addition of PB decreased the concentration of dissolved As at Eh = +100 and +200mV by 38.7% and 35.4%, respectively (compared to the control), due to the co-precipitation of As with Fe-Mn oxides and the complexation between As and aromatic organic molecules. However, PB increased As mobilization at Eh= -300 mV by 13.5%, due to promoting reduction and decomposition of As-bearing Fe minerals (e.g., ferrihydrite-As, Fe-humic-As) and facilitating As mobilization as indicated by the As K-edge XANES. PB increased As mobilization at Eh= +250mV by 317.6%, due to the associated increase of pH. We conclude that As mobilization in PB-treated paddy soils is highly controlled by Eh. PB can be used to reduce the risk of As under moderately reducing conditions, but it may increase the risk under strongly reducing and oxidizing conditions.

17525. 题目: Remediation of arsenic-contaminated soil by nano-zirconia modified biochar
文章编号: N21072110
期刊: Environmental Science and Pollution Research
作者: Miao Liu, Fengxia Sun, Yuzhen Lv, Yuxin Xu, Ming Li, Yujun Wang, Xiting Yin, Hao Jiang
更新时间: 2021-07-21
摘要: Nowadays, the soil arsenic pollution is considered as a serious environmental issue, and the high toxicity of arsenic can seriously affect the quality and safety of agricultural products and human health. Biochar, as a solidifying/passivating agent, has been widely used in the treatment of soil heavy metal pollution. Pine biochar (BC) was used as a carrier in this study, and biochar-loaded nano-zirconia (N-ZrO2-BC) was synthesized to investigate its adsorption and fixation characteristics on As (V) in soil and water. The adsorption experiment showed that the second-order kinetic equation had a good fitting effect on the adsorption curve of As (V) on the N-ZrO2-BC surface, which indicated that chemical adsorption was the main factor controlling the reaction rate. FTIR and SEM results showed that ion exchange and surface complexation were the main mechanisms of As (V) adsorption by N-ZrO2-BC. Soil culture experiments showed that the stabilization efficiency of arsenic in soil with 2% N-ZrO2-BC reached 99.30% after 60 days, and the extractable arsenic content was reduced to 3.07 μg·L-1, which reached the quality standard of class III groundwater (<0.01 mg·L-1, GB/T 14848-2017). Comparing with the control, the content of acid extractable arsenic in soil decreased by 90.57%, and the residual arsenic increased by 51.46%, indicating that the addition of N-ZrO2-BC could effectively promote the transformation of active arsenic to stable arsenic in soil.

17526. 题目: Kinetic modeling of autotrophic microalgae mainline processes for sewage treatment in phosphorus-replete and -deplete culture conditions
文章编号: N21072109
期刊: Science of The Total Environment
作者: Alexandre Viruela, Stéphanie Aparicio, Ángel Robles, Luis Borrás Falomir, Joaquín Serralta, Aurora Seco, José Ferrer
更新时间: 2021-07-21
摘要: A kinetic model of autotrophic microalgal growth in sewage was developed to determine the biokinetic processes involved, including carbon-, nitrogen- and phosphorus-limited microalgal growth, dependence on light intensity, temperature and pH, light attenuation and gas exchange to the atmosphere. A new feature was the differentiation between two metabolic pathways of phosphorus consumption according to the availability of extracellular phosphorus. Two scenarios were differentiated: phosphorus-replete and -deplete culture conditions. In the former, the microalgae absorbed phosphorus to grow and store polyphosphate. In the latter the microalgae used the stored polyphosphate as a phosphorus source for growth. Calibration and validation were performed with experimental data from a pilot-scale membrane photobioreactor (MPBR) fed with the permeate obtained from an anaerobic membrane bioreactor (AnMBR) pilot plant fed with real urban wastewater. 12 of the model parameters were calibrated. Despite the dynamics involved in the operating and environmental conditions, the model was able to reproduce the overall process performance with a single set of model parameters values. Four periods of different environmental and operational conditions were accurately simulated. Regarding the former, light and temperature ranged 10–406 μmol·m−2·s−1 and 19.7–32.1 °C, respectively. Concerning the later, the photobioreactors widths were 0.25 and 0.10 m, and the biomass and hydraulic retention times ranged 3–4.5 and 1.5–2.5 days, respectively. The validation of the model resulted in an overall correlation coefficient (R2) of 0.9954. The simulation results showed the potential of the model to predict the dynamics of the different components: the relative proportions of microalgae, nitrogen and phosphorus removal, polyphosphate storage and consumption, and soluble organic matter concentration, as well as the influence of environmental parameters on the microalgae's biokinetic processes. The proposed model could provide an effective tool for the industry to predict microalgae production and comply with the discharge limits in areas declared sensitive to eutrophication.

17527. 题目: Humic acids enrich the plant microbiota with bacterial candidates for the suppression of pathogens
文章编号: N21072108
期刊: Applied Soil Ecology
作者: Maura Santos Reis de Andrade da Silva, Orlando Carlos Huertas Tavares, Thiago Gonçalves Ribeiro, Camilla Santos Reis de Andrade da Silva, Carolina Santos Reis de Andrade da Silva, José Maria García-Mina, Vera Lúcia Divan Baldani, Andrés Calderín García, Ricardo Luiz Louro Berbara, Ederson da Conceição Jesus
更新时间: 2021-07-21
摘要: Humic acids (HA) stimulate the growth of several plant species by regulating their hormonal and redox metabolisms. Nevertheless, studies on their relationship with the plant-associated microbiota are almost nonexistent. Here, we hypothesized that the HA effect occurs in parallel with the regulation of the plant-associated bacterial community. Rice was grown for 264 h in nutrient solution supplied or not with HA (80 mg L−1). Plant growth was evaluated every 24 h and samples for 16S rRNA gene sequencing were taken after 240 h. The plant's net assimilation rate and the absolute and relative growth rates increased from 100 h to 264 h after the first HA application. The root volume and other growth variables were stimulated at different times along the plant growth cycle. Metataxonomics revealed that bacterial community structure and composition were affected upon HA application. The interactions between members of the community increased in HA-treated roots, showing more connected bacterial communities. Chitinophaga and Mucilaginibacter were the predominant genera in HA-treated roots. These bacteria are reported to produce enzymes that degrade compounds present in the wall of fungi, oomycetes, and nematode eggs. Pseudomonas and Acidobacteria Gp 1, both siderophore-producers and plant-growth promoters were also enriched, although with lower abundances. Given these results, we suggest that plants recruited these microorganisms in response to the stress caused by the HA-root interaction. For the first time, our findings indicate that HA-stimulated plants may adopt the ecological strategy of recruiting members of the bacterial community that are candidates for the suppression of pathogens and, therefore, involved in plant defense.

17528. 题目: Overlooked Contributions of Biochar-derived Dissolved Organic Matter on the Adsorption of Pb (II): Impacts of Fractionation and Interfacial Force
文章编号: N21072107
期刊: Journal of Hazardous Materials
作者: Xiaochen Huang, Bingqian Xu, Shishu Zhu, Fang Ma, Chao Jin
更新时间: 2021-07-21
摘要: Comprehensive understanding of how the release of biochar-derived dissolved organic matter (BDOM) affects the immobilization of heavy metals when biochar (BC) is applied for long-term soil remediation is extremely important. In this study, BCs prepared under different pyrolysis temperatures were fractionated into residual BC (RBC), nano-sized BC (NBC), and BDOM, in order to clarify the contribution of BDOM for lead (Pb(II)) adsorption on BC and to explore the interfacial mechanisms. Results demonstrated that the adsorption capacity (Qe) of Pb(II) on BC improved from 166.1 to 423.9mgg−1 with the increase in the pyrolysis temperature from 350 to 800 °C. The sum of Qe of Pb(II) on NBC and RBC was lower than that on BC, due to the complexation between BDOM and Pb(II) rather than pH variance and cation exchange. Ultraviolet–visible and fluorescence spectroscopy revealed that fulvic-like substances as well as small molecules with low aromaticity in BDOM underwent favorable association with Pb(II) and got re-adsorbed on RBC. With the increase in the Pb(II) concentration, the contribution of van der Waals interaction for adsorption of BDOM350-Pb complexes was improved, whereas adsorption mechanism in BDOM800-Pb complexes was more dependent on ligand exchange. This study provides mechanistic insights into the impact of BDOM on Pb(II) immobilization, which can provide valuable information for the long-term remediation of Pb-contaminated soils using BC.

17529. 题目: Highly efficient removal of DEET by UV-LED irradiation in the presence of iron-containing coagulant
文章编号: N21072106
期刊: Chemosphere
作者: Anhong Cai, Jing Deng, Cheng Ye, Tianxin Zhu, Xiao Ling, Shuwen Shen, Hongguang Guo, Xueyan Li
更新时间: 2021-07-21
摘要: N,N-Diethyl-3-methyl benzoyl amide (DEET) has been detected as an emerging pollutant in various water bodies because of its widespread use as an insect repellent. In this study, the combination of UV-LED275 and iron-containing coagulant (FeCl3) was used for the elimination of DEET in water. It was found that UV-LED275/FeCl3 (98 %) system presented a favorable removal of DEET compared with UV254/FeCl3 (59 %) and UV-LED275/Fe2(SO4)3 (81 %) processes at initial pH 3.5. DEET degradation by both UV-LED275/FeCl3 and UV-LED275/Fe2(SO4)3 processes followed pseudo-first-order kinetics with the calculated pseudo-first-order rate constants (kobs) of 0.0105 and 0.0046 cm2 mJ−1, respectively. The results of ESR analysis and radicals quenching experiments indicated that hydroxyl radicals (OH) and superoxide radicals (O2−) were responsible for DEET degradation in UV-LED275/FeCl3 process, and the former played the major role. An increase in FeCl3 dosage was beneficial to the degradation. In the UV-LED275/FeCl3 process, DEET degradation increased with a decrease in pH from 3.5 to 3.0, whereas it was almost completely suppressed with an increase in pH from 4.3 to 6.3. DEET degradation was almost unchanged after the introduction of NO3−, and it impeded after the addition of humic acid (HA), HCO3−, and SO42−. The plausible degradation pathway mainly involved hydroxylation, cleavage of the C–N bond, acetylation, and dealkylation. Among the disinfection by-products (DBPs) evaluated, UV-LED275/FeCl3 pretreatment generally increased the generation of trichloromethane, chloral hydrate, dichloroacetic acid, and trichloroacetic acid, which implied that further assessment of environmental risk was needed during its practical applications.

17530. 题目: Important constraints on soil organic carbon formation efficiency in subtropical and tropical grasslands
文章编号: N21072105
期刊: Global Change Biology
作者: Elaine Mitchell, Clemens Scheer, David Rowlings, M. Francesca Cotrufo, Richard T. Conant, Peter Grace
更新时间: 2021-07-21
摘要: More than 10% of Australia’s 49 M ha of grassland is considered degraded, prompting widespread interest in the management of these ecosystems to increase soil carbon (C) sequestration – with an emphasis on long-lived C storage. We know that management practices that increase plant biomass also increase C inputs to the soil, but we lack a quantitative understanding of the fate of soil C inputs into different SOC fractions that have fundamentally different formation pathways and persistence in the soil. Our understanding of the factors that constrain SOC formation in these fractions is also limited, particularly within tropical climates. We used isotopically labelled residue (13C) to determine the fate of residue-C inputs into short-lived particulate organic matter (POM) and more persistent mineral-associated organic matter (MAOM) across a broad climatic gradient (ΔMAT 10℃) with varying soil properties. Climate was the primary driver of above-ground residue mass loss which corresponded to higher residue-derived POM formation. In contrast, MAOM formation efficiency was constrained by soil properties. The differential controls on POM and MAOM formation highlight that a targeted approach to grassland restoration is required; we must identify priority regions for improved grazing management in soils that have a relatively high silt + clay content and CEC, with a low C saturation in the silt + clay fraction to deliver long-term SOC sequestration.

17531. 题目: Biochar-N fertilizer interaction increases N utilization efficiency by modifying soil C/N component under N fertilizer deep placement modes
文章编号: N21072104
期刊: Chemosphere
作者: Hao Xia, Muhammad Riaz, Mengyang Zhang, Bo Liu, Yuxuan Li, Zeinab El-Desouki, Cuncang Jiang
更新时间: 2021-07-21
摘要: The situation of imbalance application of nitrogenous fertilizers in maize production is a serious issue in China, and excessive nitrogen (N) application is hazardous to sustainable agricultural production and environment. In this experiment, two biochar levels (C0: 0, C1: 2 %), three different N rates (N1: 50, N2: 100, and N3: 200 mg kg−1), and two fertilization methods (T: traditional N fertilizer application mode and D: deep N fertilizer placement mode) were set up to study the response of different treatments on maize yield, N uptake, and N use efficiency. Herein, we found that fresh and dry biomasses were increased by 292 % and 283 % under C1N3 treatment with the deep application of N fertilizer compared to the control treatment (without nitrogen fertilizers and biochar). According to structural equation modeling (SEM), soil physical and chemical properties, N component and C component in different soil layers were associated with biochar and N fertilizer treatment, especially at 20–40 depth. The combination of N fertilizer and biochar application promoted the effects of biochar on the improving NUE of plants. The biochar alleviated the loss of soil nitrogen (from 52.00 to 25.94 %) under traditional N fertilizer application. Overall, excessive input of N fertilizer not only promotes the growth of crops but also causes a waste of resources and environmental pollution. We suggest that combined application of biochar and N fertilizer could significantly reduce N loss, and improve root growth and N uptake, resulting in improving NUE by improving soil environment (pH, SOM, EC) and adjusting soil C/N component.

17532. 题目: Low-Cost Biochar Adsorbents Prepared from Date and Delonix Regia Seeds for Heavy Metal Sorption
文章编号: N21072103
期刊: Bioresource Technology
作者: Dan Bahadur Pal, Arvind Singh, Jay MantJha, Neha Srivastava, Abeer Hashem, Maha Abdullah Alakeel, Elsayed Fathi Abd Allah, Vijai Kumar Gupta
更新时间: 2021-07-21
摘要: In this study, low-cost biochar as bio-adsorbents derived from locally accessible delonix regia seed and date seeds were explored for heavy metal environmental cleaning. These prepared biochars were characterized by proximate and elemental analyses, CHNS/O analysis, Fourier-transformed infrared spectroscopy and thermo-gravitational methods. Bio-sorbent’s ability to adsorb arsenic ions in synthetic wastewater was studied and optimized at varying solution pH, adsorbent dose, and starting metal concentrations. Experimentation and optimization studies were also carried out with the help of Design-software 6.0.8. The trials were designed by using response-surface methods, which includes three components and stages of Box-Behnken design. Date seeds derived-biochars eliminated 95% of arsenic from synthetic wastewater, whereas Delonix regia seeds removed 93.8%. The kinetics, isotherms and mechanism of As adsorption were also postulated. This study proposes that these seed’s biochars might be employed as an effective, low-cost, and environmentally friendly adsorbent to remove heavy metals from the environment.

17533. 题目: Aging reduces the bioavailability of copper and cadmium in soil immobilized by biochars with various concentrations of endogenous metals
文章编号: N21072102
期刊: Science of The Total Environment
作者: Hongbiao Cui, Qiuya Wang, Xue Zhang, Shiwen Zhang, Jing Zhou, Dongmei Zhou, Jun Zhou
更新时间: 2021-07-21
摘要: Biochar is widely used for environmental remediation. However, the effects of aging on the bioavailability of trace metals in biochar-amended soil remain largely unknown, especially for the biochars with various concentrations of endogenous metals. In this study, three biochars marked as BB, MB, and HB were produced from the straws of Pennisetum sinese grown in background soil, moderately-, and highly-polluted soils by trace metals, respectively. We distinguished the effects of dry-wet (DW) and freeze-thaw (FT) aging on the bioavailability of copper (Cu) and cadmium (Cd) from soil particles, the biochar interior, and the surface of biochar. The adsorption capacities of Cu2+ and Cd2+ followed the order of BB > MB > HB. DW and FT aging both increased the adsorption capacity of Cu2+, but decreased that of Cd2+ in the three biochars, resulting in a reduction in Cu bioavailability and increase in Cd bioavailability in the biochars after the saturated adsorption of Cu2+ and Cd2+. The incorporation of the three biochars decreased Cu bioavailability compared to the control after incubation for 30d, while the addition of MB increased Cd bioavailability. DW and FT aging decreased Cu bioavailability in biochar-amended soil by decreasing the bioavailability of Cu adsorbed on the biochar surface and immobilized by soil particles. Meanwhile, aging decreased Cd bioavailability by decreasing the bioavailability of Cd immobilized by soil particles. Overall, environmental risk would be increased by the application of biochars with high endogenous Cd. The major implications are that biochar dosage and environmental risk should be carefully assessed before large-scale, continuous application, especially for biochars containing high contents of endogenous trace metals.

17534. 题目: Influence of modified biochar supported Fe–Cu/polyvinylpyrrolidone on nitrate removal and high selectivity towards nitrogen in constructed wetlands
文章编号: N21072101
期刊: Environmental Pollution
作者: Weihao Hou, Sen Wang, Yue Li, Ziran Hao, Yi Zhang, Fanlong Kong
更新时间: 2021-07-21
摘要: In this study, the biochar (BC) supported Fe–Cu bimetallic stabilized by PVP (Fe–Cu/PVP/BC) were prepared and utilized to enhance the nitrate (NO3−) removal and the selectivity toward nitrogen (N2). Results showed the optimum Fe:Cu:BC ratio and the dosage of the BC (pyrolysis at 700 °C) supported Fe–Cu bimetallic stabilized by polyvinylpyrrolidone (PVP) (Fe–Cu/PVP/BC700) were respectively 1:2:3 and 1 mg L−1 with the selectivity toward N2 of 31 %. This was mainly due to the synergy among Fe0, Cu0 and BC in the Fe–Cu/PVP/BC. The addition of Fe0 could reduce the NO3− through providing electron. The Cu0 and BC improved the selectivity of NO3− to N2 through forming [Cu–NO2−ads] and adjusting redox potential. The addition of Fe–Cu/PVP/BC could supply electrons for denitrification and enhance the relative abundances of Azospira and Thauera related to denitrification to improve NO3− removal. This result was further confirmed by the variations of denitrifying functional genes (narG, nirK, nirS and nosZ). This research provided an effective method to improve NO3− removal during surface water treatment in constructed wetlands (CWs) by adding Fe–Cu/PVP/BC.

17535. 题目: Oil palm agroforestry shows higher soil permanganate oxidizable carbon than monoculture plantations in Eastern Amazonia
文章编号: N21072012
期刊: Land Degradation & Development
作者: Mila Façanha Gomes, Steel Silva Vasconcelos, Arleu Barbosa Viana‐Junior, Alessa Nayhara Mendanha Costa, Priscila Castro Barros, Osvaldo Kato, Debora Cristina Castellani
更新时间: 2021-07-20
摘要: The expansion of oil palm (Elaeis guineensis Jacq.) cultivation in degraded areas has increased in the Brazilian Amazon. Cultivation of oil palm in diversified agroforestry systems may be a relatively sustainable alternative to monocultures for crop expansion. Here, we evaluated the effect of oil palm cultivation systems on soil C, an important indicator of the soil quality of production systems. We assessed (1) whether these systems of oil palm cultivation alter the potassium permanganate oxidizable C content (POx-C) and the C management index (CMI), and (2) how the POx-C varied among management zones (harvest path, leaf pile, weeded circle, and diversified strip). The soil C indices of the oil palm cultivation systems were also compared with those of secondary forests. POx-C varied consistently based on the pattern agroforestry > secondary forest = monoculture, ranging from 0.95 ± 0.14 (agroforestry) to 0.66 ± 0.10 g·kg−1 (monoculture). The POx-C pattern among management zones was pile > diversified strip = weeded circle > harvest path. The CMI was higher in agroforestry than in monoculture. We found that these indices are sensitive to land-use systems and management practices that affect organic matter input. Organic fertilization and species diversity likely drive the improvement of soil quality in agroforestry systems than in monocultures through C input to the soil directly and indirectly, by creating favorable conditions for the action of root and fauna that in turn positively affect soil C. Therefore, we postulate that soil quality improves through oil palm agroforestry than through oil palm monocultures.

17536. 题目: Tellurite Adsorption onto Bacterial Surfaces
文章编号: N21072011
期刊: Environmental Science & Technology
作者: Jennifer L. Goff, Yuwei Wang, Maxim I. Boyanov, Qiang Yu, Kenneth M. Kemner, Jeremy B. Fein, Nathan Yee
更新时间: 2021-07-20
摘要: Tellurium (Te) is an emerging contaminant and its chemical transformation in the environment is strongly influenced by microbial processes. In this study, we investigated the adsorption of tellurite [Te(IV), TeO32–] onto the common soil bacterium Bacillus subtilis. Thiol-blocking experiments were carried out to investigate the role of cell surface sulfhydryl sites in tellurite binding, and extended X-ray absorption fine structure (EXAFS) spectroscopy was performed to determine the chemical speciation of the adsorbed tellurite. The results indicate that tellurite reacts with sulfhydryl functional groups in the extracellular polymeric substances (EPS) produced by B. subtilis. Upon binding to sulfhydryl sites in the EPS, the Te changes from Te–O bonds to Te–S coordination. Further analysis of the surface-associated molecules shows that the EPS of B. subtilis contain proteins. Removal of the proteinaceous EPS dramatically decreases tellurite adsorption and the sulfhydryl surface site concentration. These findings indicate that sulfhydryl binding in EPS plays a key role in tellurite adsorption on bacterial surfaces.

17537. 题目: Ionic Strength and Species Drive Iron–Carbon Adsorption Dynamics: Implications for Carbon Cycling in Future Coastal Environments
文章编号: N21072010
期刊: Environmental Science & Technology Letters
作者: E. J. Tomaszewski, E. K. Coward, D. L. Sparks
更新时间: 2021-07-20
摘要: In coastal environments, sea level rise (SLR) will likely alter reactions between organic matter (OM) and iron (Fe) minerals. A molecular understanding of OM–Fe reactions in complex ionic matrices such as seawater is lacking. We investigated the temporal molecular composition and adsorption of coastal OM to ferrihydrite (Fh) over 24 h in low-ionic strength water (LIW) (I = 0.0009 M), mid-ionic strength water (MIW) (I = 0.003 M) (freshwater proxy), and high-ionic strength water (HIW) (I = 0.6 M) (seawater proxy). Adsorbed OM concentrations significantly (p < 0.05) decreased in HIW (2.12 ± 0.03 mg C/g Fh), compared to those in MIW (3.24 ± 0.56 mg C/g Fh) and LIW (3.74 ± 0.36 mg C/g Fh). In combination with adsorbed ions in HIW (9–195 mg/g Fh) compared to adsorbed ions in MIW and LIW (0.02–0.9 mg/g Fh), an ionic strength threshold is evident. This threshold effect was reflected in the dynamic molecular composition of OM, characterized via Fourier transform ion cyclotron mass spectrometry. In LIW and MIW, rapid sequential adsorption of polycyclic aromatic and phenolic compounds occurred, followed by increasing adsorption of highly unsaturated compounds. Conversely, OM in HIW did not exhibit observable selective adsorption. Overall, limited OM adsorption and indiscriminate fractionation as a result of SLR will likely impact carbon cycling.

17538. 题目: How properties of low molecular weight model competitors impact organic micropollutant adsorption onto activated carbon at realistically asymmetric concentrations
文章编号: N21072009
期刊: Water Research
作者: Qi Wang, Raja-Louisa Mitchell, Roberta Hofman, Jianwei Yu, Min Yang, Luuk C. Rietveld, Frederik Zietzschmann
更新时间: 2021-07-20
摘要: Low molecular weight (LMW) dissolved organic matter (DOM) is the predominant competitor for adsorption sites against organic micropollutants (OMPs) in activated carbon adsorption. However, top-down approaches using highly complex mixtures of real water DOM do not allow to concisely examine the impacts of specific LMW DOM molecular properties on competitive adsorption. Therefore, we followed a bottom-up approach using fifteen model compounds (mDOM) to elucidate how important DOM characteristics, including hydrophobicity and unsaturated structures (ring, double/triple bond), impact competitiveness. Large concentration asymmetry (∼500 μg DOC/μg OMP) made mDOM compounds, which were overall less preferentially adsorbed than OMPs, become competitive against OMPs and inhibit OMP adsorption kinetics by pre-occupation of adsorption sites. Our results revealed that both hydrophobicity interactions and π-interactions increased mDOM competitiveness, while π-interactions outweighed hydrophobic interactions. However, π-interactions could not be satisfactorily evaluated with a parameter such as specific ultraviolet absorbance (SUVA) due to interferences of carboxyl groups in aromatic mDOMs. Instead, mDOM adsorbability, described by mDOM adsorption capacity, proved to be a comprehensive indicator for mDOM competitiveness. To our knowledge, this is the first study that systematically clarifies the impacts of intricately interacting molecular properties on DOM adsorption and the related competition against OMP adsorption. DOM adsorbability may inspire a new fractionation, and assist the further isolation, identification and detailed characterization of LMW DOM competitors in real DOM-containing waters.

17539. 题目: Immobilization of heavy metal(loid)s in acid paddy soil by soil replacement-biochar amendment technology under normal wet condition
文章编号: N21072008
期刊: Environmental Science and Pollution Research
作者: Shaojun Jiang, Lianxin Duan, Guangling Dai, Yuehong Shu
更新时间: 2021-07-20
摘要: The remediation of agricultural soil contaminated by acid mine drainages (AMD) with extreme acidity and elevated concentrations of metal(loid)s still remains to be solved. In the present study, the combination of soil replacement-biochar (BC) amendment was adopted in 270-day incubation experiments to evaluate the effect on the metal(loids) (As, Pb, Cu, Cd, and Zn) immobilization and soil properties (pH, dissolved organic carbon (DOC), redox potential (Eh), and soil water holding capacity (SWC)). The incubation study showed that soil replacement-biochar amendment improved soil health by changing soil properties, which in turn exhibited significant effects on CaCl2-extracted metal(loid)s. The combination of soil replacement and biochar amendment exhibited positive effect on the immobilization of Pb, Cu, Cd, and Zn, while, the risk of As and Cd mobility induced by biochar in the ageing process should be paid attention. Further laboratory seed germination study suggested that soil replacement-biochar amendment could effectively alleviate the stress of metal(loid)s, with the treatment of S50BC achieving the best remediation results. The results of this study suggested that soil replacement-biochar amendment was a promising remediation technology for agricultural soil contaminated by AMD.

17540. 题目: Stimulation of phenanthrene and biphenyl degradation by biochar-conducted long distance electron transfer in soil bioelectrochemical systems
文章编号: N21072007
期刊: Science of The Total Environment
作者: Xixi Cai, Xiaoshan Luo, Yong Yuan, Jibing Li, Zhen Yu, Shungui Zhou
更新时间: 2021-07-20
摘要: The bioelectrochemical degradation of organic pollutants has attracted considerable attention owing to its remarkable sustainability and low cost. However, the application of bioelectrochemical system (BES) for the degradation of pollutants in soils is hindered by limitations in the effective distance in the soil matrix. In this study, a biochar-amended BES was constructed to evaluate the degradation of organic pollutants. This system was expected to extend the electron transfer distance via conductive biochar in soils. The results showed that biochar pyrolyzed at 900 °C facilitated the degradation of phenanthrene (PHE) and biphenyl (BP) in the soil BES (SBES), reaching 86.4%–95.1% and 88.8%–95.3% in 27 days, respectively. The effective distance of SBESs was estimated to be 154–271 cm away from the electrode, which increased 1.9–3 fold after the addition of biochar. Microbial community and functional gene analysis confirmed that biochar enriched functional degrading bacteria. These findings demonstrate that the promotion of long-distance electron transfer and the formation of soil conductive networks can be achieved by biochar amendment. Thus, this study provides a basis for the effective degradation of for persistent organic pollutants in petroleum-contaminated soils using bioelectrochemical strategy.