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17621. 题目: Water-Phase Exfoliated Biochar Nanofibers from Eucalyptus Scraps for Electrode Modification and Conductive Film Fabrication
文章编号: N21101903
期刊: ACS Sustainable Chemistry & Engineering
作者: Qurat Ul Ain Bukhari, Filippo Silveri, Flavio Della Pelle, Annalisa Scroccarello, Daniele Zappi, Enrico Cozzoni, Dario Compagnone
更新时间: 2021-10-19
摘要: A solvent-free strategy to produce water-dispersed biochar-nanofibers (BH-CNF) is reported, demonstrating the potential of this cost-effective and sustainable material in electrochemical sensing and fabrication of conductive films. Water-phase BH-CNF from eucalyptus scraps were achieved using a Kraft process followed by liquid-phase exfoliation assisted by the biological stabilizing agent sodium cholate. BH-CNF-based sensors were constructed following two strategies: surface modification of screen-printed electrodes and fabrication of exclusively nanofiber-based flexible sensors. The latter were fabricated through a procedure that is cost-effective and within everyone’s reach. The potentiality of the BH-CNF-based sensors has been challenged toward a wide range of analytes containing phenol moieties and applied for detection of o-diphenols and m-phenols in olive oil samples. The BH-CNF-based sensors exhibited repeatable (RSD ≤ 7%, n = 5) and reproducible (RSD ≤ 10%; n = 3) results, proving their applicability in electroanalytical applications and the robustness of the exfoliation and fabrication strategy. For sample analysis, LODs for hydroxytyrosol (LOD ≤ 0.6 μM) and tyrosol (LOD ≤ 3.8 μM), intersensor precision (RSD calibration slope < 7%, n = 3), and recoveries obtained in real sample analysis (91–111%, RSD ≤ 6%; n = 3) endorse the material exploitability in real analytical applications.

17622. 题目: Litter inputs and phosphatase activity affect the temporal variability of organic phosphorus in a tropical forest soil in the Central Amazon
文章编号: N21101902
期刊: Plant and Soil
作者: Karst J. Schaap, Lucia Fuchslueger, Marcel R. Hoosbeek, Florian Hofhansl, Nathielly Pires Martins, Oscar J. Valverde-Barrantes, Iain P. Hartley, Laynara F. Lugli, Carlos Alberto Quesada
更新时间: 2021-10-19
摘要: Purpose The tropical phosphorus cycle and its relation to soil phosphorus (P) availability are a major uncertainty in projections of forest productivity. In highly weathered soils with low P concentrations, plant and microbial communities depend on abiotic and biotic processes to acquire P. We explored the seasonality and relative importance of drivers controlling the fluctuation of common P pools via processes such as litter production and decomposition, and soil phosphatase activity. Methods We analyzed intra-annual variation of tropical soil phosphorus pools using a modified Hedley sequential fractionation scheme. In addition, we measured litterfall, the mobilization of P from litter and soil extracellular phosphatase enzyme activity and tested their relation to fluctuations in P- fractions. Results Our results showed clear patterns of seasonal variability of soil P fractions during the year. We found that modeled P released during litter decomposition was positively related to change in organic P fractions, while net change in organic P fractions was negatively related to phosphatase activities in the top 5 cm. Conclusion We conclude that input of P by litter decomposition and potential soil extracellular phosphatase activity are the two main factors related to seasonal soil P fluctuations, and therefore the P economy in P impoverished soils. Organic soil P followed a clear seasonal pattern, indicating tight cycling of the nutrient, while reinforcing the importance of studying soil P as an integrated dynamic system in a tropical forest context.

17623. 题目: Soil bacteria respond to regional edapho-climatic conditions while soil fungi respond to management intensity in grasslands along a European transect
文章编号: N21101901
期刊: Applied Soil Ecology
作者: A. Barreiro, A. Fox, M. Jongen, J. Melo, M. Musyoki, A. Vieira, J. Zimmermann, G. Carlsson, C. Cruz, A. Lüscher, F. Rasche, L. Silva, F. Widmer, L.M. Dimitrova Mårtensson
更新时间: 2021-10-19
摘要: Soil microbial community structure is determined by environmental conditions and influenced by other factors, such as the intensity of the land use management. Studies addressing the effect of environmental factors and management on grassland soil microbial communities at the continental scale are missing, and the wide range of ecosystem services provided by these ecosystems are thus also wanting. To address this knowledge gap, this study presents data on grassland soil microbial communities along a pan-European agro-ecological gradient. The transect included five geographical locations (Sweden, Germany, Switzerland, Portugal mainland, Portugal Azores). At each location, soils were collected in two regions characterized by favourable and less favourable conditions for plant growth. In each of these ten regions, grasslands along a gradient of management intensity were selected, i.e. grassland under intensive, less intensive and extensive management. Phospholipid fatty acid analysis (PLFA) was used to characterize the microbial community structure (PLFA pattern) in relation to climatic and soil properties. Over the whole geographical range, the environmental properties determined the soil microbial community structure. In Sweden and Switzerland, the regional growth conditions had the strongest influence on the soil microbial communities, while in Germany, Portugal mainland and Azores the management intensity was more important. Splitting up this whole community response into individual groups reveals that, in general, saprotrophic fungal biomarkers were highest in extensively managed grasslands while bacterial biomarkers differed mainly between the regions. We conclude that at the transect level, climate and soil properties were the most important factors influencing soil bacterial community structure, while soil fungal groups were more responsive to grassland management intensity. Overall agricultural sustainability could benefit from informed soil health promoting management practices, and this study contributes to such knowledge, showing the importance of management for the soil microbial biomass and community structure.

17624. 题目: Impact of sustainable land‐use management practices on soil carbon storage and soil quality in the Goa state of India
文章编号: N21101802
期刊: Land Degradation & Development
作者: Venkatesh Paramesh, Surendra Kumar Singh, Deepak S. Mohekar, Vadivel Arunachalam, Shiva Dhar Misra, Shankar Lal Jat, Parveen Kumar, Arun Jyoti Nath, Nirmal Kumar, Gopal Ramdas Mahajan, Tejasvi Bhagat
更新时间: 2021-10-18
摘要: Evaluating sustainable land management (SLM) practices has regional to worldwide implications. It is imperative to develop SLM under particular soil type, climate, and cropping sequence following area-specific best management practices to harness maximum profitability. The alternative land-use system (ALUS-natural forest, pasture, cashew, areca nut, coconut) on hills and agricultural land-use system (AGLUS-rice-rice, rice-pulse) in the coastal plains of Goa state in west coast India were evaluated in this study. The present study assessed the impact of sustainable land-use management practices on different fractions of soil organic carbon (SOC), its stock and soil quality index (SQI) under ALUS and AGLUS. The total SOC stocks under different land-use systems varied from 14.4 Mg C ha−1 in rice–rice rotations to 133.7 Mg C ha−1 in cashew. The lability index, available nutrients, and biochemical properties were higher in ALUS. The variation in the levels of SOC and soil quality was due to land use and management practices. The results indicated land use with areca nut (SQI=0.8) on the hills and rice–pulses (SQI=0.25) rotations on the coast had maintained soil quality of high order. We recommend promoting sustainable agriculture with ALUS on the hills and AGLUS on the coastal plains of Goa state to enhance SOC storage, improve soil quality, and increase farmers' income.

17625. 题目: The spatial variations of water quality and effects of water landscape in Baiyangdian Lake, North China
文章编号: N21101801
期刊: Environmental Science and Pollution Research
作者: Liqing Li, Xinghong Chen, Meiyi Zhang, Weijun Zhang, Dongsheng Wang, Hongjie Wang
更新时间: 2021-10-18
摘要: Baiyangdian Lake (BYD), a large shallow lake in North China, has complex water landscape patterns that are underlies spatial variations in water quality. In this study, we collected 61 water samples from three water landscapes (reed littoral zones, fish ponds, and open water) and analyzed them for water quality parameters, such as dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP). Water landscape distribution (determined using remote sensing imagery) was then used to assess correlations between water quality parameters and water landscape proportion in differently scaled buffer zones. There was substantial variation across all subareas, with TN and TP concentrations ranging from 0.90 to 4.10 mg/L and 0.06 to 0.18 mg/L, respectively, in class IV of water quality as a whole. Spatial variations in water quality were mainly caused by water landscape distribution and external nutrient inputs. There were negative correlations between DOC, TN, and TP concentrations and the area proportion of reed littoral zones in the 300 and 500 m buffers. In contrast, DOC, TN, and TP concentrations were significantly positively correlated with the area proportion of fish ponds in the 100 m buffer. Furthermore, compared with reed littoral zones, a lower ratio of nitrogen to phosphorus and a higher proportion of dissolved organic nitrogen and tyrosine-like proteins were found in fish ponds. These effects were mainly attributed to the development of internal sediment loadings due to nutrient exchange across the sediment–water interface. Therefore, dredging-based sediment removal from fish ponds should be considered to suppress internal phosphorus loading and accelerate recovery of the BYD ecosystem.

17626. 题目: Phosphorus geochemical forms and potential bioavailability in surface sediments from Edku Lagoon, Egypt, regarding diagnostic ratios (Fe:P, S:Fe, and OC:OP)
文章编号: N21101704
期刊: Journal of Soils and Sediments
作者: Mohamed A. Okbah, Gehan M. El Zokm, Ghada F. El-Said, Mona Kh. Khalil
更新时间: 2021-10-17
摘要: Purpose Sediments play an important role in the nutrient dynamics of shallow lakes. In this work, the geochemical characterization of phosphorus (P) in the surface sediments of Edku Lagoon, Egypt, was studied in Spring 2019. Spatial variation, geochemical forms of P, and the factors affecting them were discussed. The concentrations of four operationally determined bioavailable P fractions that can be extracted from the sediments were examined. These fractions were water-soluble P (WSP, F1), readily desorbable P (RDP, F2), algae-available P (AAP, F3), and NaHCO3-extractable P (Olsen P, F4). Materials and methods Thirteen surface sediment samples were collected from Edku Lagoon, and from feeder drains. Sediment geochemical properties, total P (TP), inorganic P (IP), organic P (OP), bioavailable P fractions, and diagnostic ratios (Fe:P, S:Fe, and OC:OP) were determined. The results were discussed through various statistical analyses. Results and discussion The ranges and relative percentages of these P forms of the total concentration in the lagoon sediment stations examined were in the following order: AAP (16.7–35.4; 25.7 ± 6.65%) > Olsen P (9.1–13.8; 11.3 ± 1.74%) > WSP (2.7–8.2; 6.0 ± 1.96%) > RDP (0.41–1.26; 0.89 ± 0.32%). The results showed that IP was the main form of TP in the sediments; its concentration was six times that of OP. The relative IP to TP ratio ranged between 69 and 98%, whereas OP accounted for 2–31% of TP. The sediments of Edku Lagoon were characterized by relatively large amounts of bioavailable P; the sum of P fractions exceeded 40% of the TP. The severe increase in AAP indicated very abundant vegetation. The diagnostic ratios (Fe:P, S:Fe, and OC:OP) were calculated. Most stations had Fe:P < 15 (high P internal loading). However, 85% of the studied sediment samples had S:Fe < 1.5 ratios, which showed high sediment potency to isolate Fe-associated P forms. The high OC:OP ratio along the studied lagoon and drains reflected the hypertrophic conditions and foreign input sources of organic carbon. Conclusions The results reflected the ability of the studied P fractions to release easily from the lagoon sediments, which contributes greatly to the abundance of P from the sediments and its ease of access to surface waters, and therefore the sediments must be dredged in Edku Lagoon. The information collected will be useful in the management and development of the examined lagoon.

17627. 题目: Dissolved free amino acids and polyamines are two major dissolved organic nitrogen sources for marine bacterioplankton in the northern slope of the South China Sea
文章编号: N21101703
期刊: Biogeochemistry
作者: Qian Liu, Ye Lu, Jun Xu, Zhuo-Yi Zhu, Yeping Yuan, Wen-Chao Ma, Yurong Qian, Chun-Sheng Wang, Xue-Wei Xu
更新时间: 2021-10-17
摘要: The northern slope water of the South China Sea (SCS) is oligotrophic. The regenerated nitrogen from dissolved organic nitrogen (DON) has been suggested to play a pivotal role in sustaining primary productivity; however, DON cycling has not been investigated there. Dissolved free amino acids (DFAAs) and polyamines (DFPAs) are two major groups of labile DON that are used rapidly by heterotrophic bacteria, and important in nitrogen cycling. Here, we measured turnover rates and concentrations of representative DFAAs (arginine and glutamic acid) and DFPAs (putrescine) in waters of the northern slope of the SCS, to estimate uptake rates and evaluate their potentials to fulfill carbon and nitrogen demands of bacterial production. Furthermore, homologs of genes encoding transporter systems for arginine (aotJ) and putrescine (potD/potF) were quantified in metagenomes from four depths at two sampling stations. The taxa encoding these genes were identified to gain insight into the composition of microbial communities potentially utilizing DFAAs and DFPAs. We found that uptake rates of two DFAAs and putrescine were more rapid than measured previously in seawater with similar environmental characteristics. The uptake of arginine and glutamic acids was estimated to account for 2.4-51% (19 ± 14%) and 2.7-59% (24 ± 20%) of bacterial carbon and nitrogen demand, respectively, and putrescine uptake contributed 4.4-100% (27 ± 33%) and 13-293% (80 ± 96%), respectively. Spatial variation in uptake rates indicated that biogeochemical cycling of DFAAs was distinct from that of DFPAs. Redundancy analysis and metagenomes demonstrated that environmental variables and distinction in bacterial assembleges using DFAAs and DFPAs could both affect their dynamics in the northern slope water of the SCS.

17628. 题目: Preparation and evaluation of humic acid–based composite dust suppressant for coal storage and transportation
文章编号: N21101702
期刊: Environmental Science and Pollution Research
作者: Xiaoxiao Yu, Xiangming Hu, Weimin Cheng, Yanyun Zhao, Zhiang Shao, Di Xue, Mingyue Wu
更新时间: 2021-10-17
摘要: To mitigate environmental pollution caused by the escape of dust during coal storage and transportation, humic acid (HA) and grafted acrylamide (AM) were used as raw materials to prepare a composite dust suppressant suitable for coal storage and transportation. Single-factor experiments were used to explore the optimal synthesis conditions of the dust suppressant, and the microstructure of the product was studied using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), scanning electron microscopy (SEM), and other methods. The wetting effect of the dust suppressant on coal was also investigated by way of molecular dynamics (MD) simulations. The experimental results showed that the dust suppressant had good wind erosion resistance (wind erosion rate 10.2%), shock resistance (loss rate 3.63%), and anti-evaporation performance, while the MD simulation and permeability analysis results showed that the dust suppressant had an excellent wetting effect on the coal surface. SEM images revealed that the dust suppressant can fill the gaps between coal dust particles and bond them together to form a consolidated layer, thereby effectively inhibiting the escape of dust sources during coal storage and transportation.

17629. 题目: Seasonal Dynamics of Surface Dissolved Organic Matter in the South China Sea and the Straits of Malacca: Implications for Biogeochemical Province Delineation of Marginal Seas
文章编号: N21101701
期刊: Journal of Geophysical Research: Biogeosciences
作者: Yixue Zhang, Ying Wu, Jing Zhang, Jie Jin, Jian Li, Zhenqiu Zhang
更新时间: 2021-10-17
摘要: Biogeochemical provinces are an important aid to identify homogeneous biogeochemical characteristics and underlying ecosystem dynamics in the open ocean. This macroscale approach, however, does not appear to be applicable to marginal seas for disregarding various small scale changes. Here, we adopted two observation schemes throughout the typical marginal seas, the South China Sea (SCS) and Straits of Malacca (MS), with continuous surface-water sampling during March and May 2018. Spatial and seasonal heterogeneity of hydrological and dissolved organic matter (DOM) properties was investigated. With a novel combination of chromophoric DOM index and classical biogeochemical parameters (temperature, salinity, chlorophyll-a, and bathymetry), we delineated five biogeochemical provinces in each season to integrate DOM pools and investigate region-specific and season-dependent biogeochemical processes. The results showed that the SCS basin was seasonally modulated by biological activities and photodegradation, resulting in the biologically active DOM pools. The western SCS seasonally received terrestrial DOM, subjected to the western boundary current under monsoon regulation. The MS was found to serve as an efficient carbon source of terrestrial substances, which exported to the northern Indian Ocean during the Northeast Monsoon. The delineation favored the simplification of complex biogeochemistry and allowed us to predict future trends in this dynamic system. Chromophoric DOM index was proven applicable to the delineation of marginal seas, that shed the light on the potential applications in biogeochemical provinces in dynamic systems.

17630. 题目: Roles of biochar in cement-based stabilization/solidification of municipal solid waste incineration fly ash
文章编号: N21101616
期刊: Chemical Engineering Journal
作者: Liang Chen, Lei Wang, Yuying Zhang, Shaoqin Ruan, Viktor Mechtcherine, Daniel C.W. Tsang
更新时间: 2021-10-16
摘要: Low-carbon stabilization/solidification (S/S) is of increasing importance for sustainable treatment of hazardous wastes. In this study, we integrated carbon-negative rice husk biochar (RBC) and yard waste biochar (YBC) as green additives into the binder for S/S of municipal solid waste incineration (MSWI) fly ash. Experimental results illustrated that the addition of both biochars promoted cement hydration reaction via pozzolanic reaction and internal curing. In particular, the incorporation of 10 wt.% RBC (rich in activated Si) significantly increased the content of C-S-H gel from 41.6 wt.% (control sample) to 52.0 wt.% and increased the average degree of connectivity of C-S-H gel from 1.43 to 1.52 as indicated by quantitative X-ray diffraction and 29Si nuclear magnetic resonance analysis. The incorporation of RBC and YBC (20 or 30 wt.%) enhanced the immobilization efficiency of potentially toxic elements in MSWI fly ash due to the additional hydration products and high adsorption ability of biochar. For instance, in R-80FA and Y-80FA samples (namely, 20 wt.% binder dosage, of which RBC or YBC accounted for 10 wt.% of binder), the immobilization efficiency for Pb could reach 96.2% and comply with the leachability limit. The biochar-modified S/S blocks achieved comparable strength to the cement-based S/S blocks, presenting a mechanically stable solidified matrix for engineering application. Therefore, this study expands the emerging application of biochar and demonstrates that biochar-augmented binder can ensure low-carbon and high-performance S/S of hazardous materials.

17631. 题目: Adsorption of metal on pineapple leaf biochar: key affecting factors, mechanism identification, and regeneration evaluation
文章编号: N21101615
期刊: Bioresource Technology
作者: Kesinee Iamsaard, Chih-Huang Weng, Li-Ting Yen, Jing-Hua Tzeng, Chakkrit Poonpakdee, Yao-Tung Lin
更新时间: 2021-10-16
摘要: Although tremendous works have been done on metal adsorption via biochar, mechanisms responsible for metal adsorption remain uncertain. This is the first work that provides direct evidence on the identification of Ni(II), Zn(II), and Cu(II) adsorption mechanisms on pineapple leaf biochar (PLB) using surface characteristics analyses, including X-ray photoelectron spectroscope (XPS), Fourier transform infrared spectroscope (FTIR), and scanning electron microscope with energy-dispersive X-ray spectroscope (SEM-EDS). From Langmuir isotherm fitting, the maximum adsorption capacity of PLB for Ni(II), Zn(II), and Cu(II) are 44.88, 46.00, and 53.14 mg g-1, respectively, surpassing all biochars reported in the literature. Findings of surface characterization techniques coupled with cation released during adsorption, cation exchange, and surface complexation mechanisms were proposed. PLB is reusable and remains sufficient adsorption capacity even six consecutive cycles via pressure cooker regeneration. With high regenerability and ultrahigh adsorption capacity, PLB defines itself as a promising adsorbent for future applications in metal-laden wastewater.

17632. 题目: Molecular characterization of the composition and transformation of dissolved organic matter during the semi-permeable membrane covered hyperthermophilic composting
文章编号: N21101614
期刊: Journal of Hazardous Materials
作者: Bo Sun, Yongshuang Li, Manjiao Song, Rui Li, Zaixing Li, Guoqiang Zhuang, Zhihui Bai, Xuliang Zhuang
更新时间: 2021-10-16
摘要: Current knowledge of dissolved organic matter (DOM) in semi-permeable membrane-covered thermophilic compost (smHTC) is limited. Therefore, this study provided a comprehensive characterization of composition and transformation of DOM in smHTC using multiple spectroscopic methods and ultrahigh resolution mass spectrometry. The results showed that the values of SUVA280, SUVA254, A240-400 (0.042, 0.048, 34.193) in smHTC were higher than those of conventional thermophilic composting (cTC) (0.030, 0.037, 18.348), and the increment of PV,n in smHTC were 2.4 times higher than that of cTC. These results suggested that smHTC accelerated the humification process by promoting the degradation of labile DOM and the production of humus-like substances. Mass spectrometry further confirmed that the DOM of smHTC possessed higher degree of aromatization and humification, based on the lower H/C (1.14), and higher aromaticity index (0.34) and double bond equivalence (10.36). Additionally, smHTC increased the proportion of carboxyl-rich, unsaturated and aromatic compounds, and simultaneously improved the degradation of aliphatic/proteins, lipids, carbohydrates, along with even some refractory substances such as CHO subcategory (24.1%), especially lignin-like structures (14.8%). This investigation provided molecular insights into the composition and transformations of DOM in smHTC, and extended the current molecular mechanisms of humification in composting.

17633. 题目: Deep dewatering of activated sludge using composite conditioners of surfactant, acid and flocculant: The mechanism and dosage model
文章编号: N21101613
期刊: Science of The Total Environment
作者: Xuejie He, Lei He, Ziyuan Lin, Jiong Zhou, Shuohui Shi, Yi Liu, Jian Zhou
更新时间: 2021-10-16
摘要: To address the problem of difficult disposal caused by poor dewaterability of high-organic sludge in wastewater treatment plant, this study developed a sludge composite conditioner (SCC) consisting of sodium dodecyl sulfate (SDS), HCl and FeCl3. It has the potential to significantly improve the dewaterability of the high-organic sludge with the VSS/MLSS of 80%. The moisture content (MC) and bound water content of sludge were reduced from 98.00 to 59.65% and from 3.42 to 0.91 g/g dry sludge (DS) after being conditioned, respectively. The surfactant (SDS) promoted the dissolution of extracellular polymeric substances (EPS). The acid (HCl) enhanced the decomposition of the sludge flocs, making the insoluble EPS peel off and turn into the liquid phase. As a result, total EPS decreased by 52.70% compared to the original sludge. In addition, due to the neutralization effect of protons and FeCl3, the Zeta potential increased remarkably from −13.80 mV to −1.72 mV and the dispersed sludge particles formed during EPS dissolution process were re-flocculated, which increased the average size of the sludge particles. The ratio of proteins (PN)/polysaccharides (PS) also increased from 1.69 to 3.81. And a quantitative model of optimum dosage of SCC agents based on the influence of the sludge PS, PN and EPS content has been established, aiming to determine the dosage of each conditioner according to the properties of target sludge. In general, the SCC provided an effective pathway for sludge deep dewatering.

17634. 题目: Evolution of physicochemical properties and bacterial community in aerobic composting of swine manure based on a patent compost tray
文章编号: N21101612
期刊: Bioresource Technology
作者: Yihui Wei, Zhengwu Liang, Yan Zhang
更新时间: 2021-10-16
摘要: The objective of this study was to explore the changes in physicochemical properties and bacterial community during swine manure composting with a new compost tray (CT). The results showed that the organic matter (OM), moisture content (MC), and C/N decreased. The total Kjeldahl nitrogen (TKN), P2O5, K2O and humic acids (HAs) contents of the compost increased. The properties of the final compost product comply with the requirements of regulation except for the moisture according to NY/T 525-2012. Firmicutes, Actinobacteria, Proteobacteria and Bacteroidetes were the major phyla during the composting. Genus Terrisporobacter played a key role in degrading organic (OM). The content of K2O was main factors driving the succession of bacterial communities. These findings shed some novel lights into the dynamic changes of physicochemical propertied and their impact on bacterial community in a composting process.

17635. 题目: Quantification of DOM effects on tetracyclines transport during struvite recovery from swine wastewater
文章编号: N21101611
期刊: Water Research
作者: Xuewei Huang, Zhi-Long Ye, Jiasheng Cai, Lifeng Lin
更新时间: 2021-10-16
摘要: Struvite (MgNH4PO4•6H2O) recovered from livestock wastewater may impose a pharmacological threat to the environment, due to the extensive existence of antibiotics in the wastewater. In this study, tetracyclines (TCs) were selected as the typical antibiotics, and the individual processes of dissolved organic matters (DOM) evolution and their effects on TCs migration in struvite recovery from swine wastewater were discriminated and quantified. Results revealed that TCs transport was contributed by the adsorption of pure struvite crystals, struvite adsorbing DOM-TCs complex and DOM aggregation, which occupied 2.29%-6.53%, 23.53%-34.66%, and 59.09%-74.19% of the total TCs migration amounts, respectively. A tangential flow filtration system was employed to divide DOM into five fractional parts on the basis of molecular weight cut-offs. Experimental results indicated that under alkaline conditions of struvite crystallization, DOMs with larger molecular weights, hydrolyzed to DOMs with smaller molecular weights, which consequently promoted TCs re-distribution in DOMs from higher molecular weights to those with lower molecular weights. Furthermore, a distribution model was developed to characterize TCs transport in struvite recovery by describing TCs distribution among various phases, including struvite adsorption, DOM-TCs complexing, DOM aggregation, and free state in the solution, respectively. These outcomes provided new understanding on DOM evolution and effects on antibiotics transport in phosphate recovery from wastewater.

17636. 题目: Insight into removals of PARAFAC components from dissolved and particulate organic matter in wastewater treatment process by two-dimensional correlation and structure equation modeling
文章编号: N21101609
期刊: Environmental Sciences Europe
作者: Benxin Yu, Dongping Liu, Jian Wang, Yingxue Sun
更新时间: 2021-10-16
摘要: Background Most particulate organic matter (POM) cannot be directly degraded in the conventional wastewater treatment, which should be transformed into dissolved organic matter (DOM) through a hydrolysis process. However, non-hydrolyzed POM in the biological treatment can limit treated efficiencies for the wastewater treatment plants (WWTPs) facilities. Hence an operational tool is indispensable for insight into removals of DOM and POM factions in the WWTP. In this study, excitation-emission matrix fluorescence spectroscopy (EEM) combined parallel factor analysis (PARAFAC), two-dimensional correlation (2D-COS) and structural equation modeling (SEM) was employed to evaluate removals of DOM and POM in a wastewater treatment plant. Results Four fluorescence components were identified in DOM and POM substances from the WWTP by EEM combined with PARAFAC, i.e., tyrosine-like (TYLF), tryptophan-like (TRLF), microbial byproduct-like (MBLF), and fulvic acid-like (FALF). In A2/O process, the TYLF and TRLF of DOM were removed to a larger extent than those of MBLF and FALF in anaerobic tank, while TYLF and MBLF of POM were removed to a great extent than those of TRLF and FALF in primary sedimentation and aerobic tanks. By the 2D-COS, a decreasing variation order of DOM fractions in the wastewater treatment process was UV-FALF → MBLF2 → Vis-FALF → TRLF → TYLF, while the decreasing order of POM fractions was Vis-FALF → UV-FALF → MBLF2 → TYLF → MBLF1 → TRLF. SEM revealed that TRLF and TYLF of DOM were degraded by anaerobic microorganism, and TRLF could be transformed partially into FALF. However, TRFL and TYLF of POM were discomposed by aerobic microorganism. Conclusions The 2D-COS and SEM can be practicable tools as EEM-PARAFAC for monitoring DOM and POM in the WWTP. The study could present a theoretical support to improving the retrofit of WWTP and formulating emission standards for organic pollutants.

17637. 题目: The impacts of intensive scallop farming on dissolved organic matter in the coastal waters adjacent to the Yangma Island, North Yellow Sea
文章编号: N21101608
期刊: Science of The Total Environment
作者: Bo Yang, Xuelu Gao, Jianmin Zhao, Lei Xie, Yongliang Liu, Xiaoqing Lv, Qianguo Xing
更新时间: 2021-10-16
摘要: In-situ field investigations coupled with incubation experiments were conducted in the coastal waters adjacent to the Yangma Island to explore the impacts of intensive bay scallop farming on the quantity and composition of dissolved organic matter (DOM). During the scallop farming period, the values of dissolved organic carbon (DOC), chromophoric dissolved organic matter (CDOM) and fluorescence dissolved organic matter (FDOM) in the mariculture area (MA) were generally higher than those in the non-mariculture area (NMA). Bay scallops released a large amount of DOM with the characteristics of high molecular weight and low degree of humification into the water column through excretion, which altered the DOM biogeochemical cycle. The DOM excretion fluxes by scallop were calculated based on incubation experiments. The results showed that, without considering the DOM transformation in the water, the excretion process of bay scallops in a growth cycle can increase the concentration of DOC, CDOM and fluorescent components C1–C4 in the seawater in MA by 19.7 μmol l−1, 0.048 m−1, 0.065 QSU, 0.164 QSU, 0.017 QSU and 0.015 QSU, respectively. Assuming that the labile part of DOM excreted by scallops was completely aerobic decomposed, it could reduce DO and pH in the seawater by ~13.4 μmol l−1 and ~ 0.018 in MA. This study highlights the impact of human activities (scallop farming activities) on DOM cycle in coastal waters, which can help guide future policy formulating of mariculture and ecological protection.

17638. 题目: Biochar aging: Impact of pyrolysis temperature on sediment carbon pools and the availability of arsenic and lead
文章编号: N21101607
期刊: Science of The Total Environment
作者: Matheus Bortolanza Soares, Carlos Eduardo Pellegrino Cerri, José A.M. Demattê, Luís Reynaldo Ferracciú Alleoni
更新时间: 2021-10-16
摘要: Arsenic (As) and lead (Pb) are potentially toxic elements capable of developing several diseases in human beings such as cancer. Several adsorbent materials, including biochars, have been adopted as alternative measures designed to reduce the availability of As and Pb in water. The retention capacity of potentially toxic elements in biochars varies according to time, feedstock, and the pyrolysis temperature to produce the biochar. Our objectives in this study were to evaluate i) the aging effect of sugarcane straw pyrolyzed biochars at 350 (BC350), 550 (BC550), and 750 °C (BC750) and their ability to immobilize As and Pb; and ii) how the pyrolysis temperature and biochar aging alter the carbon content and quality of the solution and sediment. Biochars were applied at 5% (w/w), and their aging together with As and Pb immobilization effects were evaluated every 45 days over a total period of 180 days. The results were obtained using visible ultraviolet spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy combined with physical fractionation of organic matter and multivariate statistics. The groups formed in the Principal Component Analysis indicated that the change in the availability of As and Pb was related to the aging of the biochar and the temporal changes in the content and quality of organic carbon in the sediment and solution. The pyrolysis temperature was a key factor in the (im)mobilization capacity of As and Pb during the aging of the biochar. The increase in polysaccharides and organic matter associated with the particulate fraction can enhance the release of As in solution (24%). Increasing the fraction of organic matter associated with minerals reduced the availability of Pb by 58%. These findings may provide new insights into understanding the dynamics of organic matter and its role in the immobilization of As and Pb during biochar aging.

17639. 题目: Plant mixture effects on carbon-degrading enzymes promote soil organic carbon accumulation
文章编号: N21101606
期刊: Soil Biology and Biochemistry
作者: Baogang Zhang, Yanjiang Cai, Shuijin Hu, Scott X. Chang
更新时间: 2021-10-16
摘要: Microbial decomposition of soil organic carbon (SOC) is a major determinant of the global climate and terrestrial ecosystem services. Despite the rapid loss of plant species worldwide, it remains unclear how plant species richness impacts SOC decomposition, especially the decomposition of labile vs. recalcitrant SOC. This is partly because of the variable responses of soil C-degrading enzyme activities to plant species richness. Through a global meta-analysis of 490 paired observations of plant mixtures versus monocultures, we show that plant mixtures significantly enhanced soil C-hydrolase (degrades labile C) and C-oxidase (degrades recalcitrant C) activities by 29.4 and 14.9%, respectively. However, in mixtures, C-hydrolase activity marginally (P = 0.051) increased, while C-oxidase activity significantly decreased with plant species richness. In addition, in mixtures, C-hydrolase but not C-oxidase activity significantly increased with plant functional type richness and experimental duration. These plant species richness and functional type effects on C-hydrolase and C-oxidase activities were consistent among diverse terrestrial ecosystems, plant life forms, the presence/absence of legumes, and climate types. Moreover, increases in C-hydrolase but not C-oxidase activity were positively related with increasing microbial biomass C and SOC under plant mixtures, suggesting that faster microbial decomposition and transformation of labile C pools mediate SOC accumulation at higher plant species richness. These results highlight that plant species richness differentially affects labile and recalcitrant C-degrading enzymes, thereby influencing SOC decomposition, dynamics, and accumulation.

17640. 题目: Evolution of the transport properties of soil aggregates and their relationship with soil organic carbon following land use changes
文章编号: N21101605
期刊: Soil and Tillage Research
作者: Feng Wang, Xiaoxian Zhang, Andrew L. Neal, John W. Crawford, Sacha J. Mooney, Aurélie Bacq-Labreuil
更新时间: 2021-10-16
摘要: Aggregates are functional units to describe the impact of soil structural changes on physical and biogeochemical processes in soil. Both incubation and field experiments have shown that changing agricultural practices could reshape the intra-aggregate structure in a matter of days, but most such data were obtained from a single time-point and it is hence impossible to interpret that such a change was just a temporal transition or the new equilibria towards which the aggregates had evolved following the management changes. Understanding this is indispensable as intra-aggregate structure and its ability to transport substrates modulate all biogeochemical processes involved in soil carbon and nutrient cycle. This paper investigates this using soil samples archived from a reversion experiment initiated in 2008 at Rothamsted Research (UK), where parts of a plot that had been fallow since the 1950 s were converted to wheat or grass in 2008. We used X-ray Computed Tomography images, acquired at voxel size 1.5 µm, of aggregates in the archived soils to investigate the evolution of transport property of the aggregates over time, as well as its relationship with soil organic carbon (SOC). We also evaluated the development of pore connectedness following the conversion. The results show that the transport ability of the aggregates explains the SOC change much better than the porosity, and that noticeable changes in porosity of the connected pores and their ability to transport substrates did not emerge until the sixth year after the conversion. Ten years after the conversion, there was still no sign of the porosity of the connected pores and the bulk diffusion coefficient to plateau. In addition, we found the conversion to grass changed the intra-aggregate pore geometry significantly in that the bulk diffusion coefficients of their aggregates trends with their porosities in a way differing significantly from those for the bare fallow and arable treatments. All these suggest that the intra-aggregate reconfiguration following the conversion is a slow process, and that the ability of pore space to transport substrates is more important than the habitat they provide in SOC stabilisation.