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17541. 题目: Removal of diclofenac in water using peracetic acid activated by zero valent copper
文章编号: N21072006
期刊: Separation and Purification Technology
作者: Li Zhang, Yongsheng Fu, Zhenran Wang, Gaofeng Zhou, Runyu Zhou, Yiqing Liu
更新时间: 2021-07-20
摘要: In this work, the degradation kinetics and mechanism of diclofenac (DCF) using peracetic acid (PAA) activated by zero valent copper (ZVC) were systematically investigated. It was found that PAA could be catalyzed effectively by ZVC to produce HO•, CH3COO• and CH3COOO•, which were responsible for the removal of DCF. Based on the XPS, XRD and FESEM characterization results of ZVC before and after reaction, the corrosion of ZVC was occurred to produce Cu+ under acidic condition, which was the main activator for PAA, H2O2 and O2. The recommended pH for this reaction system was 3.0, and DCF degradation was enhanced gradually with increasing ZVC dose and PAA dose. The existence of Cl-, CO32-, Fe3+, Cu2+ and dissolved organic matter (DOM) promoted DCF degradation in ZVC/PAA system, while SO42- and NO3- had almost no influence on DCF removal. Six intermediates were identified in this system, and the probable degradation mechanism of DCF was thus proposed, including seven transformation pathways, i.e., hydroxylation, amidation, dechlorination-cyclizaiton, dechlorination-hydrogenation, dechlorination-hydroxylation, decarboxylation and formylation. This study provides a new method for PAA activation and DCF removal from the polluted water.

17542. 题目: Formation and mechanisms of hydroxyl radicals during the oxygenation of sediments in Lake Poyang, China
文章编号: N21072005
期刊: Water Research
作者: Haiyan Du, Yuanxin Cao, Zhe Li, Lina Li, Huacheng Xu
更新时间: 2021-07-20
摘要: Seasonal flooding-drought transformation process of lake sediments lead to changes of dissolved oxygen and redox conditions and the resultant generation of hydroxyl radical (HO•). To date, information on HO• formation and its regulators in seasonal lake sediments is largely unexplored. In this study, a total of nineteen sediments were collected from Lake Poyang, China, with the formation and mechanisms of HO• during the oxygenation process exploring via the incubation experiments, Fe K-edge X-ray adsorption spectroscopy, ultrafiltration, and fluorescent spectroscopy. Results showed that the concentrations of HO• generated ranged from 3.75 ± 1.13 to 271.8 ± 22.81 μmol kg−1, demonstrating high formation potential and obvious spatial heterogeneity. The yield of HO• formed was positively correlated with the contents of Fe(II), sedimentary organic carbon, and dissolved organic carbon, showing a general contribution of these reduced substances to HO• formation. Furthermore, application of Fe K-edge X-ray adsorption spectroscopy revealed the key species of sedimentary Fe-smectite for HO• formation due to its high peroxidase-like activity. Besides inorganic Fe(II), the sedimentary dissolved organic matters (DOMs) represented an important regulator for HO• formation, which contributed about 2∼11% of the total HO• generation. Moreover, the DOM-induced formation potential was found to be highly related to the molecular weight distribution that the low molecular weight- (LMW, <1 kDa) fraction exhibited higher HO• formation potential than the bulk and high molecular weight- (HMW, 1 kDa-0.45 μm) counterparts. In addition, the omnipresent mineral Fe(II)-DOM interaction in sediment matrix exhibited another 2∼6% of contribution to the total HO• production. This study highlighted the importance of contents and species of Fe(II) and DOM in manipulating the HO• yield, providing new insight into understanding the formation mechanisms of HO• in the seasonal lake sediment.

17543. 题目: Modeling degradation kinetics of gemfibrozil and naproxen in the UV/chlorine system: Roles of reactive species and effects of water matrix
文章编号: N21072004
期刊: Water Research
作者: Huaying Liu, Zhichao Hou, Yingjie Li, Yajie Lei, Zihao Xu, Junjie Gu, Senlin Tian
更新时间: 2021-07-20
摘要: The UV/chlorine system has been regarded as an efficient oxidation technology for the removal of aqueous micropollutants. However, the roles of the possible radical species for this system on the elimination under environmentally relevant conditions/real waters were still largely unknown. Herein, the specific roles of radical species in the UV/chlorine oxidation degradation of gemfibrozil and naproxen as representative micropollutants were quantified by a steady-state kinetic prediction model considering the effects of water matrices. Overall, the model predicted results are consistent with the experimental data well. •OH and reactive chlorine species (RCS, such as Cl•, ClO•, and Cl2•−) contributions to gemfibrozil and naproxen degradation were water matrix specific. In pure water, both primary reactive species (i.e., •OH and Cl•) and secondary species ClO• dominated gemfibrozil and naproxen degradation, and their individual and the sum of the contributions to degradation rates reduced with pH increase of from 5 to 9. In the presence of Cl−, we found that Cl2•− and in particular ClO• were responsible for the enhanced degradation with increasing Cl− concentrations due to the considerable ClO• reactivity of gemfibrozil (1.93 × 109 M−1 s−1) and naproxen (9.24 × 109 M−1 s−1) and the rapid transformation of Cl2•− to ClO•. The presence of HCO3− notably facilitated the degradation in the UV/chlorine process because of the generation of CO3•−. CO3•− showed high reactivity with gemfibrozil and naproxen corresponding to respective second-order reaction rate constants of 2.45 × 107 and 3.50 × 107 M−1 s−1. Dissolved organic matter induced obvious scavenging for •OH, Cl•, and ClO• and greatly retarded the degradation. The constructed model considering the effects of above water matrix has successfully predicted the oxidation degradation kinetics in real waters, and both •OH and CO3•− are the predominant reactive species in the degradation. This study is helpful for comprehensive understanding the roles of possible radical species in micropollutant removal by UV/chlorine oxidation under real water matrix.

17544. 题目: Degradation and Aging of Terrestrial Organic Carbon within Estuaries: Biogeochemical and Environmental Implications
文章编号: N21072003
期刊: Environmental Science & Technology
作者: Pengfei Hou, Timothy I. Eglinton, Meng Yu, Daniel B. Montluçon, Negar Haghipour, Hailong Zhang, Gui’e Jin, Meixun Zhao
更新时间: 2021-07-20
摘要: Estuaries are action zones for organic carbon (OC) degradation and aging. These processes influence the nature of terrestrial OC (OCterr) export and the magnitude of OCterr burial in marginal seas, with important environmental implications such as CO2 release and hypoxia. In this study, we determined the contents and carbon isotopic compositions (13C and 14C) of bulk OC and fatty acids (FAs) as well as the sedimentological characteristics of suspended particulate matter (SPM) samples collected from two sites over four seasons and of surface sediment samples from three sites in the Pearl River estuary (PRE) to evaluate processes controlling OCterr degradation and aging along an estuarine gradient. We found that the abundance-weighted average C24–32FA 14C ages increased by an average of ∼1170 years for SPM and by an average of ∼3440 years in PR/PRE sediments, along the ∼60 km PRE transect. These increases in the FA age coincided with an 86% decrease in the corresponding mineral surface area-normalized FA loading along the sediment transport pathway, implying that selective degradation of labile and younger OC resulted in apparent OC aging. These measurements reveal an important shift in the nature of OC, with implications for biogeochemical cycling within estuaries and for regional environmental changes.

17545. 题目: Cattle manure biochar and earthworm interactively affected CO2 and N2O emissions in agricultural and forest soils: Observation of a distinct difference
文章编号: N21072002
期刊: Frontiers of Environmental Science & Engineering
作者: Xiaoqiang Gong, Jinbiao Li, Scott X. Chang, Qian Wu, Zhengfeng An, Chengpeng Huang, Xiangyang Sun, Suyan Li, Hui Wang
更新时间: 2021-07-20
摘要: The application of manure-derived biochar offers an alternative to avoid the direct application of manure to soil causing greenhouse gas emission. Soil fauna, especially earthworms, can markedly stimulate carbon dioxide (CO2) and nitrous oxide (N2O) emissions from soil. This study therefore investigated the effect of cattle manure biochar (added at rates of 0, 2%, or 10%, coded as BC0, BC2 and BC10, respectively) application, with or without earthworm Aporrectodea turgida, on emissions of CO2 and N2O and changes of physic-chemical properties of agricultural and forest soils in a laboratory incubation experiment. The BC10 treatment significantly enhanced cumulative CO2 emissions by 27.9% relative to the untreated control in the agricultural soil. On the contrary, the BC2 and BC10 treatments significantly reduced cumulative CO2 emissions by 16.3%–61.1% and N2O emissions by 92.9%–95.1% compared to the untreated control in the forest soil. The addition of earthworm alone significantly enhanced the cumulative CO2 and N2O fluxes in agricultural and forest soils. Cumulative CO2 and N2O fluxes were significantly increased when BC2 and BC10 were applied with earthworm in the agricultural soil, but were significantly reduced when BC10 was applied with earthworm in the forest soil. Our study demonstrated that biochar application interacted with earthworm to affect CO2 and N2O emissions, which were also dependent on the soil type involved. Our study suggests that manure biochar application rate and use of earthworm need to be carefully studied for specific soil types to maximize the climate change mitigation potential of such management practices.

17546. 题目: Peracetic acid enhanced electrochemical advanced oxidation for organic pollutant elimination
文章编号: N21072001
期刊: Separation and Purification Technology
作者: Deling Yuan, Kai Yang, Shiyu Pan, Yao Xiang, Shoufeng Tang, Liting Huang, Mengting Sun, Xiaoyu Zhang, Tifeng Jiao, Qingrui Zhang, Bing Li
更新时间: 2021-07-20
摘要: A synergistic process adding peracetic acid (PAA) in electrochemistry (EC) was established to eliminate organic contaminants in water as a novel advanced oxidation process (AOP). The introduced PAA could be activated by the EC system, substituting electrolyte and promoting the methylene blue (MB) removal than the sole PAA and conventional EC systems. A series of scavenging tests demonstrated that the activation products were hydroxyl radical (HO·) and organic radicals (R-O·) in this EC/PAA process, which both played the dominant role for the MB decontamination. The effect of PAA dose, current density, initial pH, and initial MB concentration on the MB decolorization were investigated, and the results indicated that 93.99% MB was removed with the optimized conditions of 3.6 mmol L−1 PAA, 7.5 mmol L−1 H2O2, initial pH 3, and 10 mg L−1 MB concentration. The influence of water matrix (Cl−, HCO3−, SO42−, and humic acid) for removing MB was determined, and the results showed that the MB removal was considerably inhibited by these constituents of water. Lastly, the decomposition mechanism for the MB was suggested through the outcome of mass spectrometry. This study demonstrated that the EC/PAA process could be a feasible method, advancing the development of AOP for water treatment.

17547. 题目: Study on the assessment of humification processes during biodegradation of heavy residual fuel oil
文章编号: N21071821
期刊: Science of The Total Environment
作者: Jelena Avdalović, Srđan Miletić, Olga Božović, Tatjana Šolević Knudsen, Dalibor Stanković, Nikoleta Lugonja, Snežana Spasić, Kristina Joksimović, Igor Dragičević, Miroslav M. Vrvić
更新时间: 2021-07-18
摘要: The aim of this study was to investigate the creation of humic substances during biodegradation of heavy residual fuel oil, because there are indications that substances similar to humic substances are generated during biodegradation of polycyclic aromatic hydrocarbons. In the study, which lasted for 110 days, biodegradation of heavy residual fuel oil was carried out in a layer of artificial soil substrate.. The initial concentration of the total petroleum hydrocarbon in the prepared artificial soil substrate (biopile) was 23.1 g kg-1 dry weight (d.w.). At the end of the process, the total petroleum hydrocarbons were reduced to 8.1 g kg-1 d.w. in the inoculated biopile, while the content of humic acids increased during bioremediation from 3.15 g kg-1 d.w. to 4.95 g kg-1 d.w. The humic acids extracted from biopile during the biodegradation process were characterized by various chemical techniques (elemental analysis, spectrofluorimetric analysis, electrochemical measurements, and size exclusion chromatography). The results showed that levels of C, H and the H/C ratio decreased as the biodegradation process progressed. This indicated that humic acids aromatization process took place and this was confirmed by the spectrofluorimetric analysis. The increase of oxygen percentage and the O/C ratio in the humic acids after the biodegradation treatment indicated an increase in functional oxygen groups. Additional analyses of humic acids from the inoculated biopile showed that they were transformed during the bioremediation process. They had greater redox and buffering capacities and a larger portion of the fractions had high molecular mass. Also, the humification parameters (the CHAs/CFAs ratio and CHAs/Corg ratio) increased during the biodegradation. This is one of the few studies that describes the generation of humic substances during the biodegradation of oil compounds.

17548. 题目: Heavy metal biosorption by Extracellular Polymeric Substances (EPS) recovered from anammox granular sludge
文章编号: N21071820
期刊: Journal of Hazardous Materials
作者: Benedetta Pagliaccia, Emiliano Carretti, Mirko Severi, Debora Berti, Claudio Lubello, Tommaso Lotti
更新时间: 2021-07-18
摘要: The recovery and conversion of Extracellular Polymeric Substances (EPS) from sewage sludge into bio-based commodities might improve the economics and environmental sustainability of wastewater treatment. This contribution explores the application of EPS from anammox granular waste sludge as biosorbent for the removal of heavy metals, specifically lead, copper, nickel, and zinc. Adsorption capacities equivalent or higher than well-established adsorbent media emerged from single-metal biosorption studies (up to 84.9, 52.8, 21.7 and 7.4mg/gTSEPS for Pb2+, Cu2+, Ni2+ and Zn2+, respectively). Combining spectroscopic techniques, a mechanistic hypothesis for metal biosorption, based on a combination of electrostatic interaction, ion exchange, complexation, and precipitation, was proposed. The adsorption mechanisms of extracted EPS and non-extracted EPS in the native biomass were indirectly compared by means of single-metal biosorption studies performed with pristine granules (adsorbing up to 103.7, 36.1, 48.2 and 49.8mg/gTSgranules of Pb2+, Cu2+, Ni2+, and Zn2+, respectively). In comparison with pristine anammox granules, EPS showed lower adsorption capacities except for copper and different adsorption pathways as postulated based on the adsorption data interpretation via theoretical models. The multi-metal biosorption tests excluded significant competitions among different heavy metals for the EPS binding sites, thus opening further scenarios for the treatment of complex wastewaters.

17549. 题目: Uranium isotopes as a possible tracer of terrestrial authigenic carbonate
文章编号: N21071819
期刊: Science of The Total Environment
作者: Leja Rovan, Tea Zuliani, Barbara Horvat, Tjaša Kanduč, Polona Vreča, Qasim Jamil, Branko Čermelj, Elvira Bura Nakić, Neven Cukrov, Marko Štrok, Sonja Lojen
更新时间: 2021-07-18
摘要: The concentration and isotopic composition of uranium (δ238U, 234U/238U activity ratio) in combination with traditional isotopes (δ18O, δ13C) were examined as potential tracers of authigenic carbonate formation in a karst aquifer. The U concentration and 234U/238U activity ratios in the tufa-precipitating sections of two connected karst rivers (Krka and Zrmanja, Croatia) decreased downstream in water and in precipitated carbonate due to active self-purification processes, i.e. adsorption of isotopically lighter U(VI) on mineral particles, sedimentation and co-precipitation with carbonate. The isotopic composition of carbonate in tufa mostly resembled the 234U/238U activity ratio and the δ238U values of dissolved U in water but was also affected by the presence of detrital carbonate flushed into the river from soil and weathered bedrock. This interpretation was supported by the δ18O and δ13C values of tufa, which were shifted out of equilibrium with river water and dissolved in organic carbon and in their isotopic signature, which showed the presence of lithic carbonate. Large fluctuations of the δ238U values of water, leachable U (eluted in acetic acid buffered with Na-acetate) and residual U fraction could not be fully explained by available data due to the overlapping U isotopic signatures of leachable (mainly carbonate) and residual fractions of soil, bedrock and tufa. Therefore, a long-term, systematic, seasonal and event-based observation of the isotopic composition of dissolved and suspended particulate U in water is necessary. Nevertheless, the U isotopes were found to have the potential to be used as identifiers of authigenic carbonate and the storage of CO2 in terrestrial river sediments, to improve knowledge on fluxes within local and global biogeochemical carbon cycle.

17550. 题目: The Fenton-like reaction for Arsenic removal from groundwater: Health risk assessment
文章编号: N21071818
期刊: Environmental Research
作者: Mohammed Berkani, Yasser Vasseghian, Van Thuan Le, Elena-Niculina Dragoi, Amin Mousavi Khaneghah
更新时间: 2021-07-18
摘要: In this paper, the heterogeneous Fenton like-reaction for Arsenic-contaminated groundwater remediation based on the performance of FeSO4 as an efficient and green catalyst and CaO2 as a source of H2O2 was investigated. To intensify the heterogeneous Fenton process, three oxidants were tested: sodium percarbonate (SPC), sodium persulfate (SPS), and calcium peroxide (CP). The results showed that CP and SPC had a synergetic effect on the rate of Arsenic degradation, while SPS had an antagonistic effect. On the other hand, inorganic ions such as Na+, Mg2+ have a very low impact on the Arsenic removal efficiency, while the anions Cl− and NO3− exhibited significant inhibition of Arsenic degradation. This effect may be imputed to the reaction and conversion of hydroxyl (HO•) radicals to less reactive. Thus, HCO3− and humic acid dramatically raised the degradation rate. Also, the response Surface method based on Box-Behnken design was applied to examine the suitable modeling, and optimized condition of the Fenton like-reaction process, the maximum Arsenic removal efficiency of 94.91% is obtained when [Fe3+]0 = 1.97 mM, [CaO2]0 = 1.74 mM and initial pH = 4.67. The obtained results showed that the Fenton-like reaction is an effective and reliable process for arsenic removal from groundwater with low non-carcinogenic risk (HQ) and carcinogenic risk (CR) values.

17551. 题目: Carotenoid biomarkers in Namibian shelf sediments: Anoxygenic photosynthesis during sulfide eruptions in the Benguela Upwelling System
文章编号: N21071817
期刊: Proceedings of the National Academy of Sciences
作者: Jian Ma, Katherine L. French, Xingqian Cui, Donald A. Bryant, Roger E. Summons
更新时间: 2021-07-18
摘要: Aromatic carotenoid-derived hydrocarbon biomarkers are ubiquitous in ancient sediments and oils and are typically attributed to anoxygenic phototrophic green sulfur bacteria (GSB) and purple sulfur bacteria (PSB). These biomarkers serve as proxies for the environmental growth requirements of PSB and GSB, namely euxinic waters extending into the photic zone. Until now, prevailing models for environments supporting anoxygenic phototrophs include microbial mats, restricted basins and fjords with deep chemoclines, and meromictic lakes with shallow chemoclines. However, carotenoids have been reported in ancient open marine settings for which there currently are no known modern analogs that host GSB and PSB. The Benguela Upwelling System offshore Namibia, known for exceptionally high primary productivity, is prone to recurrent toxic gas eruptions whereupon hydrogen sulfide emanates from sediments into the overlying water column. These events, visible in satellite imagery as water masses clouded with elemental sulfur, suggest that the Benguela Upwelling System may be capable of supporting GSB and PSB. Here, we compare distributions of biomarkers in the free and sulfur-bound organic matter of Namibian shelf sediments. Numerous compounds—including acyclic isoprenoids, steranes, triterpanes, and carotenoids—were released from the polar lipid fractions upon Raney nickel desulfurization. The prevalence of isorenieratane and β-isorenieratane in sampling stations along the shelf verified anoxygenic photosynthesis by low-light-adapted, brown-colored GSB in this open marine setting. Renierapurpurane was also present in the sulfur-bound carotenoids and was typically accompanied by lower abundances of renieratane and β-renierapurpurane, thereby identifying cyanobacteria as an additional aromatic carotenoid source.

17552. 题目: Pyrolysis Solves the Issue of Organic Contaminants in Sewage Sludge while Retaining Carbon—Making the Case for Sewage Sludge Treatment via Pyrolysis
文章编号: N21071816
期刊: ACS Sustainable Chemistry & Engineering
作者: Wolfram Buss
更新时间: 2021-07-18
摘要: Contaminants of emerging concern are a growing burden for sewage sludge recycling. Pyrolysis of sewage sludge could be a solution. Yet, the product of sewage sludge pyrolysis (biochar) is currently not included on the list of eligible fertilizers in the new EU Fertilising Products Regulation. This was justified by insufficient evidence for organic contaminant removal through pyrolysis. Here I summarize the current evidence on this topic covering 20 studies and more than 100 different organic pollutants. The studies demonstrate that pyrolysis reduces the concentration of well-established contaminants, such as PAHs, PCBs, and dioxins, but also emerging ones, i.e., pharmaceuticals, hormones, antibiotics, antibiotic resistance genes, antimicrobials, microplastics, and per- and polyfluoroalkyl substances (PFAS) with very high efficacy (>95 to >99% in most cases). After pyrolysis, the levels of organic contaminant in biochar were typically below the limit of detection. Furthermore, modern pyrolysis units prevent environmental release of contaminants that are only vaporized and not decomposed during pyrolysis by internal combustion of pyrolysis liquids and gases. The evidence for effective organic contaminant removal through pyrolysis is comprehensive, covering all relevant groups of compounds. This and its potential as negative emission technology makes pyrolysis of sewage sludge a great opportunity for sustainable and safe nutrient recycling.

17553. 题目: Facile preparation of antifouling nanofiltration membrane by grafting zwitterions for reuse of shale gas wastewater
文章编号: N21071815
期刊: Separation and Purification Technology
作者: Minli Hu, Qidong Wu, Chen Chen, Songmiao Liang, Yuanhui Liu, Yuhua Bai, Alberto Tiraferri, Baicang Liu
更新时间: 2021-07-18
摘要: Complex organic matter causes severe fouling when membranes are applied for shale gas wastewater (SGW) treatment. This study reports the grafting of a zwitterionic polymer brush consisting of poly (sulfobetaine methacrylate) (PSBMA) onto the surface of a commercial nanofiltration (NF) membrane via electron transfer-atom transfer radical polymerization (ARGET-ATRP) to achieve anti-fouling property, especially against organic foulants. Compared to the pristine NF membranes, the PSBMA-grafted NF membrane showed high performance when challenged by SGW as a feed stream: (1) The flux stability was significantly improved during long-term operation, with a 64.28% increase in flux normalization at 50% recovery rate of SGW, while maintaining a suitable initial flux and near constant ion removal rate; (2) Based on excitation-emission-matrix spectra integrated in the fluorescence region, the removal of protein-like organic matters and humus-like organic matters increased by 34% and 16.5%, respectively; (3) The XDLVO theory supports the hypothesis that the hydrophobic interactions between the membrane surface and organic foulants were reduced by enhancing the Lewis acid-base interaction energy. The proposed anti-fouling zwitterionic membranes has potential in industrial application for the on-site reuse of SGW.

17554. 题目: Optimized isolation method of humin fraction from mineral soil material
文章编号: N21071814
期刊: Environmental Geochemistry and Health
作者: Jerzy Weber, Elżbieta Jamroz, Andrzej Kocowicz, Magdalena Debicka, Jakub Bekier, Irmina Ćwieląg-Piasecka, Aleksandra Ukalska-Jaruga, Lilla Mielnik, Romualda Bejger, Maria Jerzykiewicz
更新时间: 2021-07-18
摘要: Humic substances, including humin fraction, play a key role in the fate of organic and inorganic xenobiotics contaminating the environment. Humin is an important fraction of humic substances, which has been the least studied to date. This is due to the difficulties connected with its isolation that pose a number of methodological problems. Methods of humin fraction isolation can be divided into following main groups: (1) digestion of mineral soil components with HF/HCl followed by alkali extraction of HA and FA; (2) alkali extraction of HA and FA followed by extraction of humin by different organic solvents; and (3) alkali extraction of HA and FA followed by HF/HCl digestion of mineral soil components. Nevertheless, each of these methods has different limitations. We described in detail a useful procedure of humin isolation, in which this fraction was not extracted, but isolated from the soil by removing its soluble organic and mineral components. A modified method of HA and FA extraction with 0.1 M NaOH, according to the International Humic Substances Society, was used in the first step. Then, the mineral components in the residue were digested with the 10% HF/HCl. Unlike the procedures oriented to increase the concentration of organic matter, samples were treated several times with the HF/HCl mixture until the mineral fraction was almost completely digested. The main assumption of the method modification was to obtain the highest yield with the lowest possible ash content, but without affecting humin chemical structure. The results showed that the proposed procedure is characterized by a high efficiency and recovery and, therefore, it can be used to isolate high amounts of humin from soil.

17555. 题目: Persistence and vertical distribution of neonicotinoids in soils under different citrus orchards chrono sequences from southern China
文章编号: N21071813
期刊: Chemosphere
作者: Taihui Zheng, Jie Zhang, Chongjun Tang, Yongfen Zhang, Jian Duan
更新时间: 2021-07-18
摘要: Continual input of neonicotinoid insecticides occurs in the citrus orchards from southern China. However, it is still unknown about the variations in the distribution and accumulation of neonicotinoids in soil profiles along a long-term chronosequence of cultivation and the driving factors contributing to these shifts. Here, changes of neonicotinoids in the 0–100 cm soil profiles with distinct orchard cultivation age (1, 10, and 20 years) were investigated, and their related factors were further determined. The results showed that the total levels of five target neonicotinoids (∑5NEOs) in the soil profiles were in the range of 0–25.76 ng/g dw. Imidacloprid was the most dominating neonicotinoid, followed by thiamethoxam. We observed higher neonicotinoid accumulations in the soil profiles from the citrus orchards after 10 and 20 years of cultivation. Neonicotinoids migrated deeper into the soil profiles in orchards with a longer time since cultivation. Imidacloprid, thiamethoxam, and the total amount of neonicotinoid (∑5NEOs) were mainly affected by the cultivation age of citrus orchards (accounting for 58.9% variance; P < 0.001); whereas clothianidin, acetamiprid, and thiacloprid were mainly influenced by soil depths (accounting for 66.9–85.2% variance; P < 0.05). Redundancy analyzes further indicated that the enhanced accumulation of neonicotinoids was mainly correlated with the increase of soil organic carbon (SOC) content and soil porosity, and the reduction of bulk density in the profiles of citrus orchards with increasing cultivation age. This study highlights the finding that we should give more concerns about the contamination and ecological risks of neonicotinoids in the orchards with a long cultivation age.

17556. 题目: Study on synchronous immobilization technology of heavy metals and hydrolyzed nitrogen during pyrolysis of sewage sludge
文章编号: N21071812
期刊: Journal of Environmental Chemical Engineering
作者: Runqi Chen, Xiaoqian Ma, Zhaosheng Yu, Limei Chen, Xinfei Chen, Zhen Qin
更新时间: 2021-07-18
摘要: The difficulty to simultaneously passivate heavy metals and enrich nutrients content in sewage sludge limits its application as soil nutrients. This paper concentrated on the synchronous immobilization effect of heavy metals and hydrolyzed nitrogen during pyrolysis of sewage sludge. Results showed that the forms of heavy metals transformed from bioavailable forms (F1 + F2) to stable forms (F3 + F4) and the leaching concentration reduced after low-temperature pyrolysis. However, hydrolyzed nitrogen would inevitably lose during pyrolysis treatment. With the addition of CaO, more hydrolyzed nitrogen could be retained in biochar by forming more stable nitrogen-containing compounds. The preservation efficiency of hydrolyzed nitrogen in biochar was over 50% when pyrolysis at 300 ºC with CaO. In addition, the addition of CaO would further reduce the heavy metals toxicity. In this study, the synchronous immobilization of heavy metals and hydrolyzed nitrogen in biochar was realized by adding CaO during low-temperature pyrolysis, contributing to achieving the resource utilization of sewage sludge as N-fertilizer to land use.

17557. 题目: Source profiling of air pollution and its association with acute respiratory infections in the Himalayan-bound region of India
文章编号: N21071811
期刊: Environmental Science and Pollution Research
作者: Manzoor A. Wani, Amit K. Mishra, Saloni Sharma, Ishtiaq A. Mayer, Mukhtar Ahmad
更新时间: 2021-07-18
摘要: The studies related to air pollutants and their association with human health over the mountainous region are of utmost importance and are sparse especially over the Himalayan region of India. The linkages between various atmospheric variables and clinically validated data have been done using various datasets procured from satellite, model reanalysis, and surface observations during 2013–2017. Aerosol optical depth, air temperature, and wind speed are significantly related (p < 0.001) to the incidence of acute respiratory infections with its peak during winter. Model-derived particulate matter (PM2.5) shows high contributions of black carbon, organic carbon, and sulfate during winter. The wind roses show the passage of winds from the south–west and southern side of the region. Back trajectory density plot along with bivariate polar plot analyses have shown that most of the winds coming from the western side are taking a southward direction before reaching the study area and may be bringing pollutants from the Indo-Gangetic Plain and other surrounding regions. Our study shows that the accumulation of pollutants in the Himalayan valley is owing to the meteorological stability with significant local emissions from burning of biomass and biofuels along with long-range and mid-range transport during the winter season that significantly correlated with the incidence of acute respiratory infections in the region.

17558. 题目: The effect of black carbon on the chemical degradability of PCB1 via TENAX desorption technology from the perspective of adsorption states
文章编号: N21071810
期刊: Chemosphere
作者: Weijian Xu, Jin Zhang, Yutao Shen, Hao Yu, KeZhen Chen, Yinghong Zhu, Chaofeng Shen, Liping Lou
更新时间: 2021-07-18
摘要: Chemical degradation is one of the crucial methods for the remediation of hydrophobic organic compounds (HOCs) in soil/sediment. The sequestration effect of black carbon (BC) can affect the adsorption state of HOCs, thereby affecting their chemical degradability. Our study focused on the chemical degradability of 2-Chlorobiphenyl (PCB1) sequestrated on the typical BC (fly ash (FC), soot (SC), low-temperature biochar (BC400) and high-temperature biochar (BC900)) by iron-nickel bimetallic nanomaterials (nZVI/Ni) based on TENAX desorption technology. The results showed that PCB1 adsorbed in various states were simultaneously dechlorinated by nZVI/Ni. Specifically, rapid-desorption-state PCB1 tended to degrade more easily than resistant-desorption-state PCB1. Moreover, the degradation mechanism varied according to the type of BC. In the case of FC and SC, the degradation rate was lower than the desorption rate for the PCB1 in rapid and slow desorption states, and the degradation rate of PCB1 in the resistant desorption state was negligible. The PCB1 on FC and SC was first desorbed from BC and then degraded. However, in terms of BC400 and BC900, the degradation rate was higher than the desorption rate, and the degradation rate of the resistant-desorption-state PCB1 was 1.4×10−2 h−1 and 4.1×10−2 h−1, respectively. The graphitized structure of BC900 can directly transfer electrons, so more than 90% of the resistant-desorption-state PCB1 could be degraded. In addition, BC may affect the longevity of nZVI/Ni, thereby affecting its degradability. Therefore, the chemical degradability of BC-adsorbed HOCs should be comprehensively evaluated based on the adsorption state and the properties of BC.

17559. 题目: Assessment and mitigation of toddlers’ personal exposure to black carbon before and during the COVID-19 pandemic: A case study in Singapore
文章编号: N21071809
期刊: Environmental Research
作者: Phuong T.M. Tran, Max G. Adam, Rajasekhar Balasubramanian
更新时间: 2021-07-18
摘要: Black carbon (BC), an important indicator of traffic-related air pollution (TRAP) in urban environments, is receiving increased attention because of its adverse health effects. Personal exposure (PE) of adults to BC has been widely studied, but little is known about the exposure of young children (toddlers) to BC in cities. We carried out a pilot study to investigate the integrated daily PE of toddlers to BC in a city-state with a high population density (Singapore). We studied the impact of urban traffic on the PE of toddlers to BC by comparing and contrasting on-road traffic flow (i.e., volume and composition) in Singapore in 2019 (before the COVID-19 pandemic) and in 2020 (during the COVID-19 pandemic). Our observations indicate that the daily BC exposure levels and inhaled doses increased by about 25% in 2020 (2.9 ± 0.3 μg m−3 and 35.5 μg day−1) compared to that in 2019 (2.3 ± 0.4 μg m−3 and 28.5 μg day−1 for exposure concentration and inhaled dose, respectively). The increased BC levels were associated with the increased traffic volume on both weekdays and weekends in 2020 compared to the same time period in 2019. Specifically, we observed an increase in the number of trucks as well as cars/taxis and motorcycles (private transport) and a decline in the number of buses (public transport) in 2020. The implementation of lockdown measures in 2020 resulted in significant changes in the time, place and duration of PE of toddlers to BC. The recorded daily time-activity patterns indicated that toddlers spent almost all the time in indoor environments during the measurement period in 2020. When we compared different ventilation options (natural ventilation (NV), air conditioning (AC), and portable air cleaner (PAC)) for mitigation of PE to BC in the home environment, we found a significant decrease (>30%) in daily BC exposure levels while using the PAC compared to the NV scenario. Our case study shows that the PE of toddlers to BC is of health concern in indoor environments in 2020 because of the migration of the increased TRAP into naturally ventilated residential homes and more time spent indoors than outdoors. Since toddlers’ immune system is weak, technological intervention is necessary to protect their health against inhalation exposure to air pollutants.

17560. 题目: Effects of chlorine disinfectants on the microbial community structure and the performance of anaerobic digestion of swine manure
文章编号: N21071808
期刊: Bioresource Technology
作者: Zhijiang Shao, Xiaohui Guo, Qiang Qu, Kang Kang, Qiyuan Su, Chao Wang, Ling Qiu
更新时间: 2021-07-18
摘要: The residual chlorine disinfectants (CDs) in swine slurry could negatively impact the anaerobic digestion (AD). The objective of this study was to investigate the effects of CDs on mesophilic and thermophilic AD. The results indicated that CDs exerted inhibition effects on methanogenesis at the initial stage of mesophilic AD, leading to the extension of lag time from 0.62 days for control to 0.85, 1.9, 3.8, and 5.5 days with the increasing CDs concentrations of 50, 100, 200, and 400 mg/L, respectively. Under thermophilic condition, the inhibition effects reduced significantly at the initial stage but a decrease of CMPu at later stage was observed. The microbial analysis revealed that CDs resulted in the enrichment of chlorine-resistant bacteria (Clostridum_sensu_stricto_1) and archaea (Methanosarcina). Addition of activated carbon (AC), zero-valent iron (ZVI) and biochar (BC) was evaluated for alleviating the inhibitions of CDs and proved to be feasible strategies to alleviate the inhibited AD.