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141. 题目: Tertiary denitrification and organic matter variations of secondary effluent from wastewater treatment plant by the 3D-BER system
文章编号: N20071913
期刊: Environmental Research
作者: Shan Huang, Yuan Lu, Xin Li, Yongze Lu, Guangcan Zhu, Mahdi Hassan
更新时间: 2020-07-19
摘要:

A three-dimensional biofilm-electrode reactor (3D-BER) was constructed to facilitate the tertiary denitrification of the secondary effluent of wastewater treatment plants (SEWTP) under 12 mA and in the absence of a carbon source. The TN removal efficiency was 63.8%. The path of the formation and transformation of nitrogen, the relationship between the TN and COD removal rate and the relative concentration and composition of organic matter in the influent and effluent were analyzed to clarify the possible pathways of N and C transformation in the 3D-BER system. Under the action of an electric current, 4.4 mg NH4+-N·L−1 and 17.7 mg COD·L−1 accumulated in the 3D-BER system, and the removal rates of TN and COD were strongly and positively correlated (R2 = 0.9353). The microorganisms in the 3D-BER system under the action of electric current secreted organic matter, some of which (humic acid and microbial metabolites) could be further electrolyzed by microorganisms into bioavailable organic matter for heterotrophic denitrification. Partially dissolved organic matter (DOM, tryptophan aromatic protein, humic acid and microbial metabolites) in the SEWTP could be hydrolyzed under the action of the electric current in the 3D-BER system and consisted of bioavailable organic matter for heterotrophic denitrification. The contribution of heterotrophic denitrification to TN removal was greater than 11.7%. Therefore, the 3D-BER system removed a portion of DOM through microbial electrohydrolysis and promoted the coupling of hydrogen autotrophic denitrification and heterotrophic denitrification to enhance the effectiveness of nitrogen removal in SEWTP. Overall, this technique is effective for enhancing tertiary denitrification in SEWTP.

142. 题目: Dissolved organic carbon in rainwater from a karst agricultural area of Southwest China: Variations, sources, and wet deposition fluxes
文章编号: N20071912
期刊: Atmospheric Research
作者: Jie Zeng, Fu-Jun Yue, Min Xiao, Zhong -Jun Wang, Qixin Wu, Cai-Qing Qin
更新时间: 2020-07-19
摘要:

Dissolved organic carbon (DOC) plays a key role among the earth-surficial ecosystem, particularly in the climate change, but very few researches focused on the rainwater DOC in karst agricultural region (vulnerable agro-ecosystem). To identify the concentrations, seasonal variations, controlling factors, deposition fluxes, and potential sources of DOC in rainwater, 85 rainwater samples were collected at the Houzhai catchment, a representative karst agriculture-intensive region in Southwest China, from June 2016 to May 2017. The concentrations and deposition flux of DOC were 0.63 mg C L−1 (volume-weighted mean) and 0.67 g C m−2 yr−1. These values were lower than the Asian average value, reflecting a low level of contaminated atmospheric organic carbon in the studied area. Seasonally, low DOC concentrations were often accompanied by high deposition flux during the rainy season (heavy rainfall), suggesting that the amount of rainfall is the critical factor controlling the rainwater DOC. Moreover, long-distance migration and anthropogenic emissions were also the non-negligible impact factors. The source identification showed that both agriculture-related volatilization and fossil fuel burning (mainly coal-combustion) were the primary sources of rainwater DOC according to the correlation analysis with the major ions (typical indicators), while the contribution of other origins (e.g., plant-released, biomass burning, and windblown dust) were limited. This study clearly explores the karst-agricultural wet deposition process of DOC that would strongly benefit the study of the global carbon biogeochemical cycle.

143. 题目: Removal of 4-chlorophenol, bisphenol A and nonylphenol mixtures by aqueous chlorination and formation of coupling products
文章编号: N20071911
期刊: Chemical Engineering Journal
作者: Wenrui Xiang, Ruijuan Qu, Xinghao Wang, Zunyao Wang, May Bin-Jumah, Ahmed A. Allam, Feng Zhu, Zongli Huo
更新时间: 2020-07-19
摘要:

Phenolic endocrine disrupting chemicals (EDCs) such as bisphenol A (BPA), 4-chlorophenol (4-CP) and nonylphenol (NP) are the most commonly detected pollutants in natural environments. The transformation of mixtures of the three phenolic pollutants during chlorination process was studied for the first time in this work. Single phenol can be effectively removed by free chlorine via electrophilic substitution and electron transfer reactions, with the generation of chlorinated phenols and self-coupling products. In mixture solution, the apparent second-order rate constants (kapp) of 4-CP, BPA and NP at pH 8.0 was increased by 8.6%, 25% and 16%, respectively, as compared to the degradation of single-compound. According to the products identification and density functional theory calculations, the cross-coupling process can occur more easily than the self-coupling reaction, which might accelerate the removal of phenolic mixtures. In addition, humic acid (HA) exerts some inhibitory effect on the degradation of phenolic compounds, due to the competition for chlorine consumption and the reduction of phenoxy radicals to parent phenols. These findings shed light on the environmental fate of phenolic mixtures during aqueous chlorination process, which provide new information for the application of chlorination in water and wastewater treatment.

144. 题目: Trace organic contaminants abatement by permanganate/bisulfite pretreatment coupled with conventional water treatment processes: Lab- and pilot-scale tests
文章编号: N20071910
期刊: Journal of Hazardous Materials
作者: Jie Chen, Jinfeng Ling, Bo Sun, Jian Wang, Baoxue Zhou, Xiaohong Guan, Yuankui Sun
更新时间: 2020-07-19
摘要:

Bisulfite-activated permanganate (PM/BS) process has proven to be a promising method for trace organic contaminants (TrOCs) abatement. However, to our knowledge, most previous studies on PM/BS process were limited in synthetic water at lab-scale. Hence, the performance of TrOCs abatement by PM/BS process was investigated in real waters in this study, and for the first time, its feasibility as a pretreatment process was evaluated at pilot-scale. The lab-scale results indicated that almost all tested TrOCs could be completely removed from pure water, while their removal efficiencies varied widely from ∼20 % to ∼90 % in real waters. Correlation analysis suggested that TrOCs abatement decreased linearly with increasing concentration of dissolved organic matter (DOM) and halide ions in real waters. The TrOCs with electron-donating groups were more likely to be decomposed in PM/BS process. The PM/BS pretreatment produced MnO2 and decreased the aromatic signal of the DOM, which enhanced the removal of DOM during subsequent coagulation-sedimentation processes. Comparing with ozonation, chlorination, and permanganate processes, PM/BS process showed some advantages in terms of TrOCs abatement and operating costs. Furthermore, the pilot-scale experiment confirmed that PM/BS process combined with traditional water treatment processes could achieve excellent TrOCs abatement (greater than 84%).

145. 题目: Organic matter degradation characteristics of coastal marine sediments collected from the Seto Inland Sea, Japan
文章编号: N20071909
期刊: Marine Chemistry
作者: Satoshi Asaoka, Waqar Azeem Jadoon, Akira Umehara, Kazuhiko Takeda, Sosuke Otani, Masaki Ohno, Nobuhide Fujitake, Hiroshi Sakugawa, Hideo Okamura
更新时间: 2020-07-19
摘要:

Organic matter in marine sediment is mainly categorized into three fractions depending on degradability: labile, semi labile and refractory. The degradability of coastal marine sediments depends on the properties of the organic matter contained in the sediments. The purpose of this study was to quantify labile and refractory organic matter in coastal marine sediments with different characteristics collected from the Seto Inland Sea, and to discover the factors controlling the degradability of organic matter. Refractory organic matter content in sediments ranged from 4.7–21.4 mg g−1, a percent composition equivalent to 72–97% of TOC. In contrast, labile and semi-labile content were 0.1–1.4 mg g−1 and 0.1–2.3 mg g−1, respectively, a percent composition equivalent to 0.5–12.9% and 1.8–17.1% of TOC, respectively. Approximately 93% of refractory organic matter was categorized into humin. Organic matter originated from marine phytoplankton settled on the surface of sediments and changed to humin or a refractory organic matter. This study contributes to a better understanding of the organic matter degradation characteristics of coastal marine sediments and provides important parameters for estimating carbon budget and carbon cycling in coastal sea systems.

146. 题目: Water extractable organic C and total N: The most sensitive indicator of soil labile C and N pools in response to the prescribed burning in a suburban natural forest of subtropical Australia
文章编号: N20071908
期刊: Geoderma
作者: Dianjie Wang, Kadum Mohammed Abdullah, Zhihong Xu, Weijin Wang
更新时间: 2020-07-19
摘要:

Soil labile carbon (C) and nitrogen (N) pools are important indicators of soil fertility that are sensitive to environmental disturbance. However, few studies have periodically examined the long-term dynamics of soil labile C and N pools following prescribed burning and their implications on nutrient cycling in forest ecosystems. In this study, 0–5, 5–10, and 10–20 cm soil depths were sampled multiple times, spaning six years across a series of prescribed burning sites in a eucalypt natural forest of subtropical Australia. Water extractable organic C (WEOC) and total N (WETN), hot water extractable organic C (HWEOC) and total N (HWETN), microbial biomass C (MBC) and N (MBN) were analysed and correlated with the post-fire recovery time and other major environmental factors. Prescribed burning had long-lasting impact on WEOC and WETN for nearly 12 years following the burning. The lengthy recovery time was associated with the slow recovery in the forest floor of organic layers, which significantly diminished upon the burning. This was longer than the proposed 8–10 year burning cycle in Toohey Forest, and necessitated extending the burning cycle or reducing burning intensity to preserve the soil fertility. The WEOC and WETN were the most sensitive indictors of burning disturbances on soil labile C and N pools in this forest ecosystem. The MBC & MBN, and HWEOC & HWETN, however, did not show consistent patterns of recovery. More studies are needed to differentiate between the burning impacts and the seasonal impacts in the context of intensifying climate change and urban developments.

147. 题目: Preparation of N-doped biochar from sewage sludge and melamine for peroxymonosulfate activation: N-functionality and catalytic mechanisms
文章编号: N20071907
期刊: Science of the Total Environment
作者: Md Manik Mian, Guijian Liu, Huihui Zhou
更新时间: 2020-07-19
摘要:

In this study, a group of nitrogen-doped sludge biochar were prepared by a single-step pyrolysis method and employed as catalysts for the activation of peroxymonosulfate (PMS). The N content of as-synthesized biochar composites was altered by adding a different ratio of melamine with the precursors. The sample characterization results indicated that the N content of sludge-melamine-blended biochar named SM-(0.5:1) significantly increased from 1.91 to 9.93% compared with that of raw sludge biochar. Consequently, the surface area and mesoporosity also enhanced. SM-(0.5:1) exhibited excellent degradation ability of reluctant organic pollutants in PMS/acidic media, which outperformed many previously reported carbocatalysts. Complete color removal of a mixture solution of seven cationic and anionic dyes (10 mg L−1 of each) was achieved within 50 min by using 200 mg L−1 of SM-(0.5:1) and 350 mg L−1 of PMS. A mechanism study indicated that the non-radical process performed by the pyridine N dominated the oxidative degradation of pollutants rather than that of SO4 and OH radical process governed by graphitic N, CO, and surface metal oxides. This study concurrently provides a facile route of enhancing N functionality of sludge-based carbocatalysts and an efficient way of sludge valorization.

148. 题目: Application of zinc and biochar help to mitigate cadmium stress in bread wheat raised from seeds with high intrinsic zinc
文章编号: N20071906
期刊: Chemosphere
作者: Muhammad Farooq, Aman Ullah, Muhammad Usman, Kadambot H.M. Siddique
更新时间: 2020-07-19
摘要:

Cadmium (Cd) contamination in soil negatively impacts crop productivity, grain quality, and human health. Wheat seeds, with different concentrations of intrinsic zinc (Zn): low Zn (35 mg kg−1), medium (42 mg kg−1), and high Zn (49 mg kg−1), were planted in artificially contaminated soil (10 mg Cd kg−1 soil). Zinc (5 g kg−1) and biochar (20 g kg−1 soil) were applied alone or in combination at sowing. Cadmium contamination reduced wheat growth, productivity, and grain Zn concentration, relative to the respective no-Cd treatments, with greater reductions in plants with low intrinsic Zn. Among the soil amendments, Zn and/or biochar improved wheat productivity and grain Zn and reduced grain Cd concentration in plants grown from seed with varying intrinsic Zn levels. Plants from high intrinsic Zn seeds performed better under Cd stress with the application of soil amendments than seeds with low or medium intrinsic Zn levels. The combined application of Zn and biochar had the highest increases in grain yield (9.51%) and grain Zn concentration (12.2%), relative to the control (no Cd, no Zn, and no biochar). This treatment also decreased the Cd concentrations in straw (7.1%) and grain (95.6%). The sole application of Zn or biochar improved wheat productivity and grain Zn concentration and deceased grain Cd concentration under Cd stress, but more improvements resulted from the combined application of Zn and biochar. Plants grown from seed with high Zn were better able to tolerate Cd stress than the plants raised from seeds with medium and low Zn levels.

149. 题目: MnO2-decorated biochar composites of coconut shell and rice husk: An efficient lithium ions adsorption-desorption performance in aqueous media
文章编号: N20071905
期刊: Chemosphere
作者: Urooj Kamran, Soo-Jin Park
更新时间: 2020-07-19
摘要:

Lithium (Li+) is used in various applications involving pharmaceuticals, textile dyes, and batteries. Therefore, the demand for environmentally friendly and effective materials for Li+ uptake and recovery continues to increase. Herein, rice husk (RH) and coconut shell (CS) biomasses were used to fabricate honeycomb-networked biochar (BC) precursors via slow pyrolysis. RHBC- and CSBC-based MnO2 composites were synthesized by depositing MnO2 in various ratios onto RHBC and CSBC by varying the KMnO4 concentration (2%, 3%, and 4%), followed by simple ultrasonication and heat-treatment methodologies. The structural and physicochemical properties of all of the fabricated composites were analyzed using several different instrumental methods. The batch adsorption experiments were performed for comparative Li+-adsorption studies of RHBC-Mnx and CSBC-Mnx composites by optimizing several parameters (pH, adsorbent dose, Li+ initial concentration, and contact time). The comparative adsorption analysis revealed that the RHBC-Mnx composites exhibited stronger Li+-adsorption ability than the CSBC-Mnx composites and that increasing the MnO2 deposition to 3% in both cases led to maximum Li+ adsorption capacities (62.85 mg g−1 and 57.8 mg g−1), respectively. The kinetic studies show that Li+ adsorption proceeds through the pseudo-second-order mechanism. Li+ recovery was successfully carried out using HCl (eluting agent), thereby demonstrating the benefits of synthesized composites at the industrial scale. The current work indicates that the fabricated RHBC-Mnx and CSBC-Mnx composites may have potential for use as economical composites in eco-friendly applications such as Li+ adsorption and recovery from aqueous media.

150. 题目: Nearshore zone dynamics determine pathway of organic carbon from eroding permafrost coasts
文章编号: N20071904
期刊: Geophysical Research Letters
作者: Dirk Jong, Lisa Bröder, George Tanski, Michael Fritz, Hugues Lantuit, Tommaso Tesi, Negar Haghipour, Timothy I. Eglinton, Jorien E. Vonk
更新时间: 2020-07-19
摘要:

Collapse of permafrost coasts delivers large quantities of particulate organic carbon (POC) to arctic coastal areas. With rapidly‐changing environmental conditions, sediment and organic carbon (OC) mobilization and transport pathways are also changing. Here, we assess the sources and sinks of POC in the highly‐dynamic nearshore zone of Herschel Island ‐ Qikiqtaruk (Yukon, Canada). Our results show that POC concentrations sharply decrease, from 15.9 to 0.3 mg L‐1, within the first 100 – 300 meters offshore. Simultaneously, radiocarbon ages of POC drop from 16,400 to 3,600 14C years, indicating rapid settling of old permafrost POC to underlying sediments. This suggests that permafrost OC is, apart from a very narrow resuspension zone (<5 m water depth), predominantly deposited in nearshore sediments. While long‐term storage of permafrost OC in marine sediments potentially limits biodegradation and its subsequent release as greenhouse gas, resuspension of fine‐grained, OC‐rich sediments in the nearshore zone potentially enhances OC turnover.

151. 题目: A decision support framework assessing management impacts on crop yield, soil carbon changes and nitrogen losses to the environment
文章编号: N20071903
期刊: European Journal of Soil Science
作者: M.D. Young, G.H. Ros, W. De Vries
更新时间: 2020-07-19
摘要: Agricultural management practices have multiple impacts on farming systems, including crop yield, soil fertility parameters such as soil organic carbon (SOC), and environmental quality. Agricultural decision support tools (DSTs) are key in sustainable farm strategies to optimize yield and minimize environmental losses since both the current agroecosystem properties as well as the effectiveness of management practices are highly variable in time and space. Here, we introduce a highly data‐driven framework focusing on the evaluation of agronomic measures to reach agronomic and environmental targets. We demonstrate the potential of this approach by a proof of principle for 81 selected farm types across Europe, focusing on measures with respect to crop rotation, fertilization and soil tillage. Synthesizing data from long‐term experiments and meta‐analytical models, we estimated the impact of these measures on crop yield, SOC and N surpluses, while accounting for site specific properties for the current and desired situation. The impacts of these measures on all farm types have been quantified, and optimum sets of agronomic measures have been selected in order to maximize crop yield and SOC levels and minimize N surpluses to reach the critical values for NO3‐ concentrations in ground water. Our results, quantifying trade‐offs among sustainability indicators that have traditionally been analyzed separately, illustrate that the suitability of measures varies by soil, climate and crop types within Europe. Our approach is promising for mapping region‐specific management recommendations and evaluating the effectiveness of agronomic measures over multiple environmental goals and targets.

152. 题目: Molecular Fingerprints of Soil Organic Carbon in Wetlands Covered by Native and Non-native Plants in the Yellow River Delta
文章编号: N20071902
期刊: Wetlands
作者: Zhe Li, Zhongsheng Zhang, Min Li, Haitao Wu, Ming Jiang
更新时间: 2020-07-19
摘要: This study compared soil organic carbon (SOC) in wetlands dominated by native and one invasive plant specie to better understand how short-term Spartina alterniflora colonization affected carbon circulation in the Yellow River Delta (YRD). Freshwater marsh dominated by Phragmites australis (FM) had the highest SOC, total nitrogen (TN), and water-extractable organic carbon (WEOC) contents, whereas SOC contents varied only slightly among salt marshes covered by Suaeda salsa (SM2), S. alterniflora (SM3) and bare flat (MD). Invasion by S. alterniflora substantially changed the molecular characteristics of SOC. The spectral characteristics of Fourier-transform infrared spectroscopy (FTIR) of humic acids (HAs) were similar from 4000 to 1800 cm−1 but differed greatly from 1800 to 1000 cm−1 among four wetlands. Pyrolysis-gas chromatography/mass spectrometry technology (Py-GC/MS) was used to characterize molecular fingerprints of HAs. Aliphatics (27.38%), lignin (16.64%), nitrogen-containing compounds (Nc) (16.16%), polysaccharides (16.93%), and phenol (13.42%) were dominant in FM, and aliphatics, alkyl, and Nc were primary in HAs from MD, SM2, and SM3. Lignin moieties were only found in HAs from FM and SM3, which accounted for about 16.64% and 1.6% of the total ion current, respectively. The absorption bands of the FTIR spectrum around 3340 and 1650 cm−1 in FM samples were much larger than those in the other three wetlands. However, the ratio of the peak areas at 1620 and 2930 cm−1 (R1620/2930) in SM3, was lower than that in MD and SM2, and it meant carbon in SM3 was less stable. Proportions of lignin and phenol moieties to total ion counts (TIC) in MD and SM2 were 3.3% and 3.4%, while these proportions in FM and SM were 30% and 7.5%, respectively. It showed S. alterniflora invasion into salt marsh would increase SOC contents and its stability, while it will inverse if freshwater marsh was supplanted by S. alterniflora in the YRD.

153. 题目: Adsorption Characteristics of Tetracycline onto Biochars as Affected by Solution Chemistry Conditions and Ball Milling Treatment
文章编号: N20071901
期刊: Water, Air, and Soil Pollution
作者: Xiaohan Ma, Yanjun Xin, Qinghua Yan, Xiangrui Pan, Shuaishuai Xin, Xiaomin Huang, Qinghua Chen, Guocheng Liu
更新时间: 2020-07-19
摘要: Biochars from Chinese medicine material residues and furfural residues at 300–600 °C (MBC300–MBC600 and FBC300–FBC600) were used as adsorbents for removing tetracycline (TC) from water. The influence of pH and co-existing of cations or low molecular weight organic acids (LMWOAs) was investigated on TC adsorption. Further, the bulk biochars were treated by ball milling into sub-micron particles, and their properties and adsorption performance toward TC were also characterized. For pristine biochars, TC adsorption was nonlinear and heterogeneous. Heterogeneity of biochars resulted in multiple sorption mechanisms, including H-bonding, π-π interaction, and pore filling. FBC300 and FBC600 had maximum sorption at pH 5–7. Electrostatic repulsion of positively charged biochar surfaces with TCH3+ at pH < 3 or negatively charged biochar surfaces with TCH and/or TC2− at pH > 7 was not favorable for TC removal. TC sorption decreased with increasing Na+ concentrations from 0 to 0.1 mol/L, and bivalent cations (Ca2+ and Mg2+) showed greater inhibiting effect relative to monovalent ones (Na+ and K+). The LMWOAs could combine with co-existing cations, thus reducing the inhibitory effect of cations and improving TC sorption. The ball milling caused remarkable size reduction of biochar particles, thus exposing more active surfaces to capture more TC molecules from water. This study provided low-cost and high-efficiency biochar absorbents to remove antibiotics from water and will benefit for understanding the relationship between TC sorption characteristics/mechanisms and biochar properties.

154. 题目: Losses of phosphorus, nitrogen, dissolved organic carbon and soil from a small agricultural and forested catchment in east-central Finland
文章编号: N20071819
期刊: Agriculture, Ecosystems and Environment
作者: Mari Räty, Kirsi Järvenranta, Erkki Saarijärvi, Jari Koskiaho, Perttu Virkajärvi
更新时间: 2020-07-18
摘要:

Livestock-derived phosphorus (P) loading values are largely based on studies performed in small experimental fields, leading to uncertainties when applying the results at larger scale. This five-year study estimated annual loads of P, nitrogen (N), dissolved organic carbon (DOC) and total suspended solids (TSS) in a small 3.2 km2 agricultural and forested catchment by monitoring water quality and discharge in four ditches reflecting different land uses. The monitored catchment has intensive livestock production, with proportions of grassland, cereal and forest area typical for east-central Finland. Typically, spring runoff started in early April under snow cover and peaked during snowmelt. There was great variation in the amount and pattern of discharge between years. Mean annual total P (TP) load (± SD) from an agricultural sub-catchment was 1.0 ± 0.37 kg ha−1. Mean TP load from a forested (PS) sub-catchment was 0.4 ± 0.17 kg ha−1 when a point source of pollution (PS) was included and 0.06 kg ha-1 when it was excluded. The point source of pollution contributed 12 % of the TP load from the whole 3.2 km2 catchment. The proportion of dissolved reactive P (DRP) to TP load varied between 34 % and 67 % in the study period (largest for the forested (PS) sub-catchment and smallest for the whole catchment). Observed erosion rates were very low when measured as TSS, with the highest (115 ± 103 kg ha−1) and lowest (3.4 ± 2.3 kg ha−1) mean annual erosion rate in the agricultural and forested (PS) sub-catchments, respectively. In the agricultural sub-catchment, the relationship between TP and DOC tended to be stronger than that between TP and TSS. Mean annual total N load from the agricultural sub-catchment was 19.0 ± 7.2 kg ha−1 and from the whole catchment 10 ± 2.7 kg ha−1, while mean annual DOC load was 45 ± 13 kg ha-1 and 92 ± 28 kg ha−1, respectively. These results are important in developing, implementing and targeting mitigation measures to control agricultural nutrient losses to surface waters.

155. 题目: Organic compounds evolution and sludge properties variation along partial nitritation and subsequent anammox processes treating reject water
文章编号: N20071818
期刊: Water Research
作者: Weigang Wang, Hongchao Xie, Han Wang, Hao Xue, Junjie Wang, Mingda Zhou, Xiaohu Dai, Yayi Wang
更新时间: 2020-07-18
摘要:

Reject water contains complex components of organic compounds, which have significant influences on the nitrogen removal performance when treated using biological autotrophic nitrogen removal technology. In this study, a two-stage partial nitritation (PN)-anammox (floc-granule) system was established to treat reject water (COD/NH4+-N = 0.97 ± 0.15), and the evolution of organic compounds along PN and annamox bioreactors was investigated using gas chromatography–mass spectrometry and excitation-emission matrix. Also, the variation of PN and anammox sludge properties relating to COD reduction was examined. The PN-anammox system removed approximately 80% of total inorganic nitrogen and COD with hydraulic reaction time of 16 hours. The influent organics (330–600 mg COD/L) in reject water were primarily composed of volatile, protein-like and humic acid-like organic compounds. PN process contributed 53 ± 18% of the overall COD removal, primarily including oxygen-containing organics (e.g. phenol), proteins and humic acids. Anammox process contributed 22 ± 15% of the overall COD removal, but large molecule acids (e.g. lactic acid) and small molecule alcohols (e.g. glycerol) were reoccurred, contributing to the effluent COD with recalcitrant hydrocarbons (e.g. n-Octadecane). Reject water increased the extracellular proteins/polysaccharides ratio of PN and anammox sludge, promoting the adsorption and degradation of organic compounds. High-throughput sequencing results showed that denitrifying bacteria of Ottowia increased from 0.03% to 14.4% in PN reactor, and of Denitratisoma increased from 9.6% to 15.4% in anammox reactor. The occurrence of these denitrifiers might mitigate the negative impact of organics to functional organisms. This study highlights the organics fate during PN-anammox treatment system, which is important to maintain the robust nitrogen removal when treating organics-containing and high ammonium concentration wastewater.

156. 题目: Fabrication and evaluation of silica embedded and zerovalent iron composited biochars for arsenate removal from water
文章编号: N20071817
期刊: Environmental Pollution
作者: Munir Ahmad, Adel R.A. Usman, Qaiser Hussain, Abdullah S.F. Al-Farraj, Yiu Fai Tsang, Jochen Bundschuh, Mohammad I. Al-Wabel
更新时间: 2020-07-18
摘要:

Waste date palm-derived biochar (DPBC) was modified with nano-zerovalent iron (BC-ZVI) and silica (BC-SiO2) through mechanochemical treatments and evaluated for arsenate (As(V)) removal from water. The feedstock and synthesized adsorbents were characterized through proximate, ultimate, and chemical analyses for structural, surface, and mineralogical compositions. BC-ZVI demonstrated the highest surface area and contents of C, N, and H. A pH range of 2–6 was optimum for BC-ZVI (100% removal), 3–6 for DPBC (89% removal), and 4–6 for BC-SiO2 (18% removal). Co-occurring PO43− and SO42− ions showed up to 100% reduction, while NO3 and Cl ions resulted in up to 26% reduction in As(V) removal. Fitness of the Langmuir, Freundlich and Redlich-Peterson isotherms to As(V) adsorption data suggested that both mono- and multi-layer adsorption processes occurred. BC-ZVI showed superior performance by demonstrating the highest Langmuir maximum adsorption capacity (26.52 mg g−1), followed by DPBC, BC-SiO2, and commercial activated carbon (AC) (7.33, 5.22, and 3.28 mg g−1, respectively). Blockage of pores with silica particles in BC-SiO2 resulted in lower As(V) removal than that of DPBC. Pseudo-second-order kinetic model fitted well with the As(V) adsorption data (R2 = 0.99), while the Elovich, intraparticle diffusion and power function models showed a moderate fitness (R2 = 0.53–0.93). The dynamics of As(V) adsorption onto the tested adsorbents exhibited the highest adsorption rates for BC-ZVI. As(V) adsorption onto the tested adsorbents was confirmed through post-adsorption FTIR, SEM-EDS, and XRD analyses. Adsorption of As(V) onto DPBC, BC-SiO2, and AC followed electrostatic interactions, surface complexation, and intraparticle diffusion, whereas, these mechanisms were further abetted by the higher surface area, nano-sized structure, and redox reactions of BC-ZVI.

157. 题目: Carbothermal synthesis of biochar-supported metallic silver for enhanced photocatalytic removal of methylene blue and antimicrobial efficacy
文章编号: N20071816
期刊: Journal of Hazardous Materials
作者: Jun Shi, Jun Wang, Lebin Liang, Xu Zhen, Yu Chen, Shi Chen, Xu Mengmeng, Xiaozhi Wang, Shengsen Wang
更新时间: 2020-07-18
摘要:

Pinewood biochar (PBC)-supported metallic silver (Ago) was prepared via a one-step carbothermal reduction route (AgH) or a wet-chemistry reduction method (AgW). XRD and SEM confirmed Ago was soldered on PBC matrix. Low methylene blue (MB) sorption was observed for unsupported Ago nanoparticles (AgNP), AgH and AgW. Under ultraviolet (UV) light irradiation, net MB degradation by AgH (15.88 g kg−1) was higher than that of AgW (12.50 g kg−1) and AgNP (10.27 g kg−1). TOC removal percentages after degradation corresponded largely to reduction of MB concentrations in solution, indicating MB was dominantly mineralized. Electron paramagnetic resonance (EPR) revealed that MB was degraded by reactive oxygen species (ROS) such as hydroxyl radical (OH), superoxide radical (O2-) and singlet oxygen (1O2). The scavenging experiments further suggested that OH scavengers suppressed MB degradation to a greater extent than other quenchers. Compared to AgW, AgH possessed greater abundance of persistent free radicals, which enhance ROS generation. PBC could also improve separation of electron-hole (e--h+) pairs and enhance electron transfer ascribing to favorable carbon structure. Besides, PBC-Ago maintained good antimicrobial efficacy over E.coli DH5α. This work presented a facile carbothermal route to prepare Ago-based photocatalysts for dye removal and microbial inhibition in industrial wastewater.

158. 题目: Characteristics and mechanisms of Pb(II) sorption onto Fe-rich waste water treatment residue (WTR): A potential sustainable Pb immobilisation technology for soils
文章编号: N20071815
期刊: Journal of Hazardous Materials
作者: Nina C. Finlay, Caroline L. Peacock, Karen A. Hudson-Edwards, Karen L. Johnson
更新时间: 2020-07-18
摘要:

Pb contamination of soils is a global problem. This paper discusses the ability of an Fe-rich waste, water treatment residual (WTR), to adsorb Pb(II). This was investigated using batch sorption experiments, X-ray diffraction, electron microprobe microanalysis, PHREEQC modeling and Extended X-ray Absorption Fine Structure (EXAFS) analysis. The WTR is composed of approximately 23 wt. % natural organic matter (NOM), 70 wt. % ferrihydrite and <10 wt. % silicate material. Pb(II) sorption to WTR was dependent on initial Pb(II) load, particle size, time and pH, but not on ionic strength. EXAFS analysis at the Pb LIII-edge confirmed that Pb(II) sorbed to WTR by co-existing bidentate edge-sharing and monodentate or corner-sharing complexes, with 2 O at ∼2.31–2.34 Å, 1 Fe at ∼3.32–3.34 Å, 2 Fe at ∼3.97–3.99 Å and 1 Pb at ∼3.82–3.85 Å. Linear combination showed that the Pb(II)-sorbed spectra were best fit with a ∼0.9 ± 0.1 and 0.1 ± 0.1 contribution from Pb(II)-sorbed ferrihydrite and Pb(II)-sorbed humic acid end members, respectively. Overall, we show that Pb(II) sorbs via strong inner-sphere complexation of Pb(II) to the ferrihydrite component of the WTR, which itself is stable over a wide pH range. Therefore, we suggest that Fe-rich WTR wastes could be used as effective adsorbents in Pb(II)-contaminated soils to help ensure sustainable terrestrial ecosystems.

159. 题目: Influence of algal organic matter on the attenuation of selected trace organic contaminants and dissolved organic matter in managed aquifer recharge: column studies
文章编号: N20071814
期刊: Environmental Science: Water Research & Technology
作者: Jin Hyung Noh, Soo Hyun So, Jiwon Park, Sung Kyu Maeng
更新时间: 2020-07-18
摘要: In this study, the effects of algal organic matter (AOM) from Microcystis aeruginosa on the attenuation of selected trace organic contaminants (TrOCs) were observed in a managed aquifer recharge using laboratory scale soil columns. Changes in dissolved organic matter and bacteriological characteristics were also investigated to elucidate the performance of managed aquifer recharge during algal bloom. AOM exhibited a high ratio of biopolymers and low molecular weight neutrals in DOM. DOM was effectively removed even after the addition of AOM (4 mg/L) in the feed water during soil passage; however, the removal rate was significantly reduced under abiotic conditions, confirming that the main removal mechanisms of dissolved organic matter involve biodegradation. AOM exhibited a much higher ratio of assimilable organic carbon / dissolved organic carbon than river water. Attenuation of four hydrophilic acid TrOCs (diclofenac, bezafibrate, ibuprofen, and ketoprofen) was significantly reduced in the presence of AOM during soil passage, but neutral TrOCs were not affected by AOM. It was difficult to remove carbamazepine using a managed aquifer recharge. AOM influenced the attenuation of selected TrOCs even after ozonation, followed by soil passage, reducing attenuation by 10%. Thus, it is important to monitor the removal of some TrOCs in managed aquifer recharge during algal blooms.

160. 题目: Response of soil labile organic carbon fractions and carbon-cycle enzyme activities to vegetation degradation in a wet meadow on the Qinghai–Tibet Plateau
文章编号: N20071813
期刊: Geoderma
作者: Weiwei Ma, Guang Li, Jianghua Wu, Guorong Xu, Jiangqi Wu
更新时间: 2020-07-18
摘要:

Vegetation degradation resulting from climate change and human activities in wet meadows is an important issue worldwide. This phenomenon is known to influence soil labile organic carbon (LOC) and enzyme activities due to changes in environmental conditions. However, little is known about the response of LOC and enzyme activities to vegetation degradation in high-altitude wet meadows. In this study, we examined the response of LOC and carbon-cycle enzyme activities to different intensities of vegetation degradation (i.e., non-degraded (ND), slightly degraded (SD) moderately degraded (MD), and heavily degraded (HD)) in a Tibetan wet meadow. The contents of soil organic carbon (SOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC) and light fraction organic carbon (LFOC) and the carbon-cycle enzyme activities (i.e., cellulase, amylase and β-glucosidase) were investigated in two growing seasons (2016 and 2017). We found that the content of soil SOC and LOC fractions declined with increasing soil depth in each degraded level except for HD. Vegetation degradation significantly decreased the amount of SOC at depths of 0–10 cm and 10–20 cm, and this decrease was attributed to the relative reduction of carbon source input and higher carbon decomposition. Vegetation degradation also significantly reduced the contents of SWC, DOC, MBC, LFOC, amylase and β-glucosidase in the topsoil layers (0–10 and 10–20 cm). However, the corresponding contents in deeper soil layers had no significant differences. In addition, the SWC, DOC, LFOC and the carbon-cycle enzyme activities were higher in 2016 than in 2017. Significant correlations were obtained between SWC, SOC, LOC fractions and enzyme activities. Soil moisture was found to be the main abiotic driver for variation of soil carbon and enzyme activities. Our results indicate that vegetation degradation in the Tibetan wet meadows decreased the quantity of topsoil labile carbon fractions and enzyme activities and heavily degraded vegetation may lead to a change of profile distribution in soil carbon pool.

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