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26061. 题目: Mechanistic evaluation of biochar potential for plant growth promotion and alleviation of chromium-induced phytotoxicity in Ficus elastica
文章编号: N19111205
期刊: Chemosphere
作者: Abhay Kumar, Stephen Joseph, Ludmila Tsechansky, Inga J. Schreiter, Christoph Schüth, Sara Taherysoosavi, DavidR.G. Mitchell, Ellen R. Graber
更新时间: 2019-11-12
摘要: The potential of biochar to enhance phytorestoration of hexavalent chromium [Cr(VI)]-contaminated soils was investigated. Rooted cuttings of Ficus elastica Roxb. Ex Hornem were transplanted to soil treated with 0 or 25 mg kg⁻¹ Cr(VI), ‒Cr and +Cr designations respectively, and amended with cattle manure-derived biochar at 0, 10 and 50 g kg⁻¹. Plants were grown for 180 d in a temperature-controlled greenhouse. In the ‒Cr treatment, biochar addition enhanced plant growth without affecting plant water status, leaf nutrient levels, photochemical efficiency, or hormone levels. In the absence of biochar, Ficus growth in the +Cr treatment was stunted, exhibiting decreased leaf and root relative water content and photochemical efficiency. Adding biochar to + Cr soil resulted in decreased Cr uptake into plant tissues and alleviated the toxic effects of soil Cr(VI) on plant growth and physiology, including decreased leaf lipid peroxidation. High-resolution electron microscopy and spectroscopy elucidated the biochar role in decreasing Cr mobility, bioavailability, and phytotoxicity. Spectroscopic evidence is suggestive that biochar mediated the reduction of Cr(VI) to Cr(III), which was subsequently incorporated into organomineral agglomerates formed at biochar surfaces. The dual function of biochar in improving F. elastica performance and detoxifying Cr(VI) demonstrates that biochar holds much potential for enhancing phytorestoration of Cr(VI)-contaminated soils.

26062. 题目: Understanding the interdependence of strain of electrotroph, cathode potential and initial Cu(II) concentration for simultaneous Cu(II) removal and acetate production in microbial electrosynthesis systems
文章编号: N19111204
期刊: Chemosphere
作者: Jiaxin Hou, Liping Huang, Peng Zhou, Yitong Qian, Ning Li
更新时间: 2019-11-12
摘要: Metallurgical microbial electrosynthesis systems (MES) are holding great promise for simultaneous heavy metal removal and acetate production from heavy metal-contaminated and organics-barren waters. How critical parameters of strain of electrotroph, cathode potential and initial heavy metal concentration affect MES performance, however, is not yet fully understood. Heavy metal of Cu(II) and four Cu(II)-tolerant electrotrophs (Stenotrophomonas maltophilia JY1, Citrobacter sp. JY3, Pseudomonas aeruginosa JY5 and Stenotrophomonas sp. JY6) were employed to evaluate MES performance at various cathode potentials (−900 or −600 mV vs. standard hydrogen electrode) and initial Cu(II) concentrations (60–120 mg L⁻¹). Each electrotrophs exhibited incremental Cu(II) removals with increased Cu(II) at −900 mV, higher than at −600 mV or in the abiotic controls. Acetate production by JY1 and JY6 decreased with the increase in initial Cu(II), compared to an initial increase and a decrease thereafter for JY3 and JY5. For each electrotrophs, the biofilms than the planktonic cells released more amounts of extracellular polymeric substances (EPS) with a compositional diversity and stronger Cu(II) complexation at −900 mV. These were higher than at −600 mV, or in the controls either under open circuit conditions or in the absence of Cu(II). This work demonstrates the interdependence of strain of electrotroph, cathode potential and initial Cu(II) on simultaneous Cu(II) removal and acetate production through the release of different amounts of EPS with diverse composites, contributing to enhancing the controlled MES for efficient recovery of value-added products from Cu(II)-contaminated and organics-barren waters.
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26063. 题目: Mechanistic understanding of the adsorption of natural organic matter by heated aluminum oxide particles (HAOPs) via molecular dynamics simulation
文章编号: N19111203
期刊: Journal of Membrane Science
作者: Yunqiao Ma, Sadiye Velioğlu, Melike Begum Tanis-Kanbur, Rong Wang, Jia Wei Chew
更新时间: 2019-11-12
摘要: Membrane fouling caused by natural organic matter (NOM) in water is a pressing problem. To address this, heated aluminum oxide particles (HAOPs) have been used as dynamic membranes pre-deposited onto the primary membrane to effectively remove NOM and thereby significantly diminish the fouling potential. An in-depth understanding of the mechanisms underlying the superior performance of HAOPs remains amiss, which motivated this study. Molecular dynamics (MD) simulations were conducted to systematically compare the performance of HAOPs, which have been reported to be particularly effective for high molecular weight (HMW) NOM, with the conventional powdered activated carbon (PAC) adsorbent. Six NOM constituents, three of which have HMW and three have low molecular weight (LMW), were studied. Results indicate that the mechanisms underlying the effective removal of HMW NOM by HAOPs include: (1) higher foulant-HAOPs interaction energy; (2) greater hydration of the HMW NOM, which thereby increases the affinity to the more hydrophilic HAOPs; (3) diminished mobility of the foulant once adsorbed, which deters desorption; and (4) higher peak intensities in the radial distribution functions for multiple functional groups on the HMW NOM foulants. These results are expected to be valuable towards the better design of such materials for mitigating membrane fouling.

26064. 题目: Changes of soil organic matter stability along altitudinal gradients in Tibetan alpine grassland
文章编号: N19111202
期刊: Plant and Soil
作者: Yanhui Hou, Keyi He, Ying Chen, Jingxue Zhao, Huifeng Hu, Biao Zhu
更新时间: 2019-11-12
摘要: Background and aims: Changes of soil organic matter (SOM) stability in alpine ecosystems can alter carbon release from the soil and consequently feed back to climate change. We sought to explore the altitudinal patterns of SOM stability and their relationships with climatic, vegetational and edaphic factors. Methods: We combined a number of biological, thermal, chemical, molecular and isotopic indices to characterize SOM stability in two soil layers (0–10 and 10–30 cm) of alpine grassland along two altitudinal gradients of 3200–4200 m (Haibei) and 4400–5200 m (Damxung) on the Tibetan Plateau, respectively. Results: There were significant altitudinal variations in SOM stability between the two transects. Greater biological, chemical and isotopic indices of SOM stability were observed in the middle altitude in Haibei, while opposite results were observed in Damxung. Except for a decreasing trend of SOM stability along altitudinal gradient in subsurface soils (10–30 cm) in Damxung, there was no significant altitudinal trend of thermal and molecular indices of SOM stability. The multiple indices of SOM stability were mutually associated and all showed greater SOM stability in subsurface soils than in surface soils across regions and altitudes. Conclusions: Along the altitudinal gradient, SOM stability showed opposite unimodal patterns in Haibei and Damxung, and had higher values in subsurface soils than in surface soils of the alpine grassland. Climatic, vegetational and edaphic factors collectively control SOM stability rather than just temperature or precipitation.

26065. 题目: Progress, challenges, and opportunities in enhancing NOM flocculation using chemically modified chitosan: a review towards future development
文章编号: N19111201
期刊: Environmental Science: Water Research & Technology
作者: Paripurnanda Loganathan, Michael Gradzielski, Heri Bustamante, Saravanamuthu Vigneswaran
更新时间: 2019-11-12
摘要: Natural organic matter (NOM) occurs ubiquitously in water bodies and this can greatly affect feed or raw water quality (taste, colour, odour, bacterial growth). Furthermore, it reduces the performance of the coagulation-based water treatment process. Because the NOM content and its chemical complexity are increasing throughout the world, the removal of NOM from water has become a major challenge in supplying the required amounts of good quality water. The coagulation-flocculation process is widely used for purifying urban water supplies. However, it is not always sufficiently successful in removing the augmented NOM in the feed water, mostly because the polyelectrolytes currently used as coagulants/flocculants cannot effectively interact with all the NOM components consisting of different functional groups, molecular weights, charges, and hydrophobicity. Within the class of polyelectrolytes, chitosan (Cs), which is produced by the deacetylation of abundantly available chitin, has been tested in removing NOM. The effectiveness of Cs can be further improved by chemically modifying the abundant free amino and hydroxyl groups along the Cs chain backbone. This will provide new functional groups that can increase the positive charges, molecular weight, and allow for solubility ovr a wider pH range, as well as introduce tailored groups which interact in an optimised way with NOM, thereby reducing the solubility of the formed complexes. This paper critically reviews the chemistry of the formed polyelectrolyte/NOM complexes and provides information on how this can be taken advantage of, to identify modified chemical structures of Cs to improve NOM removal in water treatment strategies.

26066. 题目: Changes in Particulate and Mineral Associated Organic Carbon with Land Use in Contrasting Soils
文章编号: N19111105
期刊: Biogeosciences
作者: Sabina Yeasmin, Balwant Singh, Cliff T. Johnston, Donald L. Sparks, and Quan Hua
更新时间: 2019-11-11
摘要: Soil organic carbon (OC) is the largest terrestrial C stock and soils' capacity to preserve OC varies with many factors including land use, soil type and depth. We investigated the effect of land use change on particulate organic matter (POM) and mineral-associated organic matter (MOM) in soils. Surface (0–10 cm) and sub-surface (60–70 cm) soil samples were collected from paired-sites (native and cropped lands) of four contrasting soils. Bulk soils were isolated into POM and MOM fractions, which were analysed for mineralogy, OC and nitrogen, isotopic signatures and ¹⁴C content. POMs of surface soils were relatively unaffected by land use change, possibly because of continuous input of crop residues, while corresponding POM in sub-surface lost more OC. In surface soils, oxides-dominated MOM lost more OC than phyllosilicates- and quartz -dominated MOM, which is attributed to diverse OM input and the extent of OC saturation limit of soils. In contrast, oxides-associated fractions were less affected in the sub-surface soils than the other two MOM fractions, possibly due to OC protection via organo–mineral associations. Changed isotopic signature (linked with vegetation) across the fractions suggested that fresh crop residues constituted the bulk of OM in surface soils (supported by greater ¹⁴C). Increased isotopic signatures and lower ¹⁴C in sub-surface MOM fractions suggested the association of more microbially processed, aged OC in oxides-rich fractions than other MOMs. Results reveal that quantity and quality of OC after land use change was influenced by the nature of C input in surface soils and by mineral-organic association in sub-surface soils.

26067. 题目: Molecular composition and decomposition stages of organic matter in a mangrove mineral soil with time
文章编号: N19111104
期刊: Estuarine, Coastal and Shelf Science
作者: Morimaru Kida, Miyuki Kondo, Mitsutoshi Tomotsune, Kazutoshi Kinjo, Toshiyuki Ohtsuka, Nobuhide Fujitake
更新时间: 2019-11-11
摘要: The molecular composition of soil organic matter (SOM) is important in understanding the elemental cycling of mangrove forests. The aim of the study was to investigate the SOM compositional changes with time in a mangrove mineral soil, which is rarely reported in the literature. A 1-m soil core was collected in the subtropical Fukido River mangrove forest (Okinawa, Japan) and separated into 25-cm sections. Humic acids (HA) and fulvic acids (FA) were extracted from the soil, and their relative abundance and chemical characteristics were analyzed by elemental analysis, stable carbon analysis, spectrophotometric measurement, liquid-state ¹³C nuclear magnetic resonance spectroscopy, and radiocarbon dating. HA exhibited a clear depth trend in the chemical characteristics, with lower H/C and N/C ratios, higher aromaticity, and higher phenolic C¹³C NMR peaks in the deeper sections. FA did not show such a clear depth trend, and was enriched in O-containing functional groups. A combination of radiocarbon dating and structural analysis of HA indicated that the rapid structural changes in HA (H/C and N/C) occurred during the first years–decades, followed by a gradual change over a time scale of several hundred (∼500) years, and these structural changes were best explained by an increase in the relative phenolic C contents. These results show that mangrove SOM is a complex mixture of organic fractions with different biogeochemical reactivities.
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26068. 题目: Compensatory effects stabilize the functioning of Baltic brackish and salt marsh plant communities
文章编号: N19111103
期刊: Estuarine, Coastal and Shelf Science
作者: Werner Ulrich, Piotr Hulisz, Jasmin Mantilla-Contreras, Tiina Elvisto, Agnieszka Piernik
更新时间: 2019-11-11
摘要: The variation in plant species abundances and in community composition appears to be a basic ecological trigger that determines changes in community functionality and resilience. Particularly, fluctuations in abundance of dominant species might indicate major changes in resource use and ecosystem functioning. Here we use quantitative surveys of Baltic brackish and salt marsh plant communities to infer how variability in species abundances and environmental conditions influence plant assimilation rates and whether compensatory effects in abundance mask variability in functionality. The variability in species richness and assimilation rates was negatively correlated with average soil organic matter content and moisture and positively correlated with soil pH. It was independent of the variability in soil conditions. The abundances of rare species and species of intermediate abundances increased with increasing community wide assimilation rates. Our findings indicate that the strength of compensatory mechanisms that stabilise assimilation rates in salt marsh environments heavily depend on soil conditions. In the present study sites benign soil conditions stabilized assimilation rates while more stressful conditions caused synchronous fluctuations in total abundance and assimilation.

26069. 题目: Dynamic nano-Ag colloids cytotoxicity to and accumulation by Escherichia coli: Effects of Fe³⁺, ionic strength and humic acid
文章编号: N19111102
期刊: Journal of Environmental Sciences
作者: Weicheng Zhang, Bingyu Ning, Caiyun Sun, Ke Song, Xin Xu, Tao Fang, Lunguang Yao
更新时间: 2019-11-11
摘要: Released Ag ions or/and Ag particles are believed to contribute to the cytotoxicity of Ag nanomaterials, and thus, the cytotoxicity and mechanism of Ag nanomaterials should be dynamic in water due to unfixed Ag particle:Ag⁺ ratios. Our recent research found that the cytotoxicity of PVP-Ag nanoparticles is attributable to Ag particles alone in 3 hr bioassays, and shifts to both Ag particles and released Ag⁺ in 48 hr bioassays. Herein, as a continued study, the cytotoxicity and accumulation of 50 and 100 nm Ag colloids in Escherichia coli were determined dynamically. The cytotoxicity and mechanisms of nano-Ag colloids are dynamic throughout exposure and are derived from both Ag ions and particles. Ag accumulation by E. coli is derived mainly from extracellular Ag particles during the initial 12 hr of exposure, and thereafter mainly from intracellular Ag ions. Fe³⁺ accelerates the oxidative dissolution of nano-Ag colloids, which results in decreasing amounts of Ag particles and particle-related toxicity. Na⁺ stabilizes nano-Ag colloids, thereby decreasing the bioavailability of Ag particles and thus particle-related toxicity. Humic acid (HA) binds Ag⁺ to form Ag⁺-HA, decreasing ion-related toxicity and binding to the E. coli surface, decreasing particle-related toxicity. HA in complex conditions showed a stronger relative contribution to toxicity and accumulation than Na⁺ or Fe³⁺. The results highlighted the cytotoxicity and mechanism of nano-Ag colloids are dynamic and affected by environmental factors, and therefore exposure duration and water chemistry should be seriously considered in environmental and health risk assessments.
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26070. 题目: Application of dead-end ultrafiltration and hollow fibre transverse vibration systems as pre-treatment for the valorisation of bioethanol dunder
文章编号: N19111101
期刊: Journal of Membrane Science
作者: Jeraz Cooper, Yun Ye, Amir Razmjou, Vicki Chen
更新时间: 2019-11-11
摘要: Valorisation of high-strength molasses spentwash (biodunder) was investigated using two-stage membrane processing for the recovery of moderate-to-high value organic acids. Conventional techniques relying on precipitation are often problematic, consuming large volumes of chemicals and have poor selectivity within complex sample matrices. Both stirred-cell and hollow fibre transverse vibration systems were compared and assessed in terms of transmembrane pressure stability, dissolved organic matter (DOM) fractionation, organic acid separation and fouling reversibility during long-term operation. For the same membrane material and effluent dilution (10 fold), stirred cell filtration with a UF 30 kDa membrane revealed a critical flux (J_critical) value of about 6.2 L/m²h, markedly lower than that obtained with a larger MWCO (UF 100 kDa) counterpart wherein J_critical was situated around 12.7 L/m²h. On the contrary, transverse vibration of submerged hollow fibres demonstrated a greater tenacity to withstand more aggressive feed solutions (i.e. 5 and 2 fold dilution) even at fluxes above J_critical, coupled with almost 60% restoration of membrane resistance by simple deionised water rinsing following 6.5 h of constant flux filtration. Size exclusion chromatography (LC-OCD) findings highlight considerable rejection of biopolymers (proteins and polysaccharides) in addition to humic, building block and LMW neutrals content of the effluent DOM. Importantly, HPLC analyses indicated the transmission of selected moderate-to-high value organic acids was greatest during submerged hollow fibre vibration with minimal (5 fold) effluent dilution. Further concentration via nanofiltration suggested almost 80% transmission of succinic acid during the polishing of UF permeate. Recovery of such constituents may contribute to substantially improve the economic viability of bioethanol production.

26071. 题目: A diurnal carbon engine explains 13 C-enriched carbonates without increasing the global production of oxygen
文章编号: N19111011
期刊: Proceedings of the National Academy of Sciences
作者: Emily C. Geyman, Adam C. Maloof
更新时间: 2019-11-10
摘要: In the past 3 billion years, significant volumes of carbonate with high carbon-isotopic ( δ 13 C) values accumulated on shallow continental shelves. These deposits frequently are interpreted as records of elevated global organic carbon burial. However, through the stoichiometry of primary production, organic carbon burial releases a proportional amount of O 2 , predicting unrealistic rises in atmospheric p O 2 during the 1 to 100 million year-long positive δ 13 C excursions that punctuate the geological record. This carbon–oxygen paradox assumes that the δ 13 C of shallow water carbonates reflects the δ 13 C of global seawater-dissolved inorganic carbon (DIC). However, the δ 13 C of modern shallow-water carbonate sediment is higher than expected for calcite or aragonite precipitating from seawater. We explain elevated δ 13 C in shallow carbonates with a diurnal carbon cycle engine, where daily transfer of carbon between organic and inorganic reservoirs forces coupled changes in carbonate saturation ( Ω A ) and δ 13 C of DIC. This engine maintains a carbon-cycle hysteresis that is most amplified in shallow, sluggishly mixed waters with high rates of photosynthesis, and provides a simple mechanism for the observed δ 13 C-decoupling between global seawater DIC and shallow carbonate, without burying organic matter or generating O 2 .

26072. 题目: Photocatalytic degradation of dye by Ag/TiO 2 nanoparticles prepared with different sol–gel crystallization in the presence of effluent organic matter
文章编号: N19111010
期刊: Environmental Science and Pollution Research
作者: Hongyu Deng, Huan He, Shijie Sun, Xintong Zhu, Dongxu Zhou, Fengxia Han, Bin Huang, Xuejun Pan
更新时间: 2019-11-10
摘要: TiO₂ nanoparticle-doped Ag (Ag/TNPs) have good photocatalytic properties based on localized surface plasmon resonance (LSPR) effect. The effluent organic matter (EfOM) can be easily activated by photo-excitation to promote pollutant photodegradation, but excessive EfOM has an inactive effect. Herein, the purpose of this paper is to investigate the changes of photocatalytic performance by Ag/TNPs in the presence of EfOM. Three Ag/TNPs made by condensation crystallization or rotary evaporation crystallization using the sol–gel method were conducted in photocatalytic degradation of methyl orange (MO). The Ag/TNPs crystallized by condensation had greater separation rate of photogenerated electron–hole pairs and photocatalytic degradation of MO with high load rates of binding Ag and TiO₂ than those formed by rotary evaporation crystallization. Indeed, EfOM could be excited to produce the active substances under illumination resulting in the promotion of MO degradation. However, contrary to previous speculation, no additive effect of MO photodegradation was observed with the addition both of EfOM and Ag/TNPs at different pH values (5~9) and ion strength (0~0.4 mol L⁻¹). It can be explained that the EfOM changed the morphology and active sites in Ag/TNPs’ surface. Meanwhile, EfOM could be consumed and degraded by Ag/TNP photocatalysis leading to the concentration of free radicals to decrease. This study revealed a nonsynergistic effect between nanomaterial and EfOM for photocatalysis. EfOM would have a negative effect on photocatalytic degradation of organic compounds by Ag/TNPs in the aquatic environment.

26073. 题目: Effects of cyanobacteria decomposition on the remobilization and ecological risk of heavy metals in Taihu Lake
文章编号: N19111009
期刊: Environmental Science and Pollution Research
作者: Lixiao Ni, Guoxiu Gu, Shiyi Rong, Lingling Hu, Peifang Wang, Shiyin Li, Dandan Li, Xuanyu Liu, Yifei Wang, Kumud Acharya
更新时间: 2019-11-10
摘要: To investigate the relationship between cyanobacteria decomposition and the remobilization of heavy metals in Taihu Lake, the indoor simulation experiments were conducted. The areas of Taihu Lake that undergo harmful algal blooms mostly caused by excessive cyanobacteria have serious problems of heavy metal pollution. The results showed that cyanobacteria decomposition can release heavy metals into the water and change the total contents and chemical speciation of Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb in sediment due to the change of physical and chemical properties in overlying water and sediment. The decomposition rate of cyanobacteria with sediment was clearly faster than that without sediment, and decomposition changed the pH and dissolved oxygen (DO) concentrations in overlying water. The cyanobacteria decomposition reduced the oxidation-reduction potential (ORP), and increased organic matter (OM) and total organic carbon (TOC) in the surface sediment. According to ecological risk assessment, the cyanobacteria decomposition increased the degree of heavy metal pollution and the potential ecological risk in sediment.

26074. 题目: Disinfection byproducts and halogen-specific total organic halogen speciation in chlorinated source waters – The impact of iopamidol and bromide
文章编号: N19111008
期刊: Journal of Environmental Sciences
作者: Nana Osei B. Ackerson, Hannah K. Liberatore, Michael J. Plewa, Susan D. Richardson, Thomas A. Ternes, Stephen E. Duirk
更新时间: 2019-11-10
摘要: This study investigated the speciation of halogen-specific total organic halogen and disinfection byproducts (DBPs) upon chlorination of natural organic matter (NOM) in the presence of iopamidol and bromide (Br⁻). Experiments were conducted with low bromide source waters with different NOM characteristics from Northeast Ohio, USA and varied spiked levels of bromide (2–30 μmol/L) and iopamidol (1–5 μmol/L). Iopamidol was found to be a direct precursor to trihalomethane (THM) and haloacetic acid formation, and in the presence of Br⁻ favored brominated analogs. The concentration and speciation of DBPs formed were impacted by iopamidol and bromide concentrations, as well as the presence of NOM. As iopamidol increased the concentration of iodinated DBPs (iodo-DBPs) and THMs increased. However, as Br⁻ concentrations increased, the concentrations of non-brominated iodo- and chloro-DBPs decreased while brominated-DBPs increased. Regardless of the concentration of either iopamidol or bromide, bromochloroiodomethane (CHBrClI) was the most predominant iodo-DBP formed except at the lowest bromide concentration studied. At relevant concentrations of iopamidol (1 μmol/L) and bromide (2 μmol/L), significant quantities of highly toxic iodinated and brominated DBPs were formed. However, the rapid oxidation and incorporation of bromide appear to inhibit iodo-DBP formation under conditions relevant to drinking water treatment.
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26075. 题目: Physicochemical features, metal availability and enzyme activity in heavy metal-polluted soil remediated by biochar and compost
文章编号: N19111007
期刊: Science of The Total Environment
作者: Jiayi Tang, Lihua Zhang, Jiachao Zhang, Liheng Ren, Yaoyu Zhou, Yuanyuan Zheng, Lin Luo, Yuan Yang, Hongli Huang, Anwei Chen
更新时间: 2019-11-10
摘要: Biochar and compost have been widely used for pollution remediation of heavy metals in soil. However, little research was conducted to explore the efficiency of biochar, compost and their combination to reduce heavy metals availability, and the effects of their additive on soil biological properties are often neglected. Therefore, this study investigated the effects of biochar, compost and their combination on availability of heavy metals, physicochemical features and enzyme activities in soil. Results showed that adding amendments to polluted soil significantly altered soil properties. Compared to the separate addition of biochar or compost, their combined application was more effective to improve soil pH, organic matter (OM), organic carbon (TOC) and available potassium (AK). All amendments significantly decreased the availability of Cd and Zn, but slightly activated As and Cu. In addition, soil enzyme activities were activated by compost and inhibited by biochar, but exhibited highly variable responses to their combinations. Pearson correlation analysis indicated that electrical conductivity (EC) and AK were the most important environmental factors affecting metal availability and soil enzyme activities including dehydrogenase, catalase, β-glucosidase, urease, acid and alkaline phosphatase, arylsulfatase except for protease and invertase. Availability of As, Cu, Cd and Zn affected dehydrogenase, catalase and urease activities. These results indicated that biochar, compost and their combination have significant effects on physicochemical features, metals availability and enzyme activities in heavy metal-polluted soil.
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26076. 题目: Assessing the potential effect of extreme weather on water quality and disinfection by-product formation using laboratory simulation
文章编号: N19111006
期刊: Water Research
作者: Chia-Jung Chang, Chin-Pao Huang, Chia-Yang Chen, Gen-Shuh Wang
更新时间: 2019-11-10
摘要: Increased frequency and severity of extreme weather events (i.e., floods and droughts) combined with higher temperatures can threaten surface water quality and downstream drinking water production. This study characterized the effects of extreme weather events on dissolved organic matter (DOM) washout from watershed soils and the corresponding contribution to disinfection by-product (DBP) precursors under simulated weather conditions. A laboratory simulation was performed to assess the effects of temperature, drought, rainfall intensity, sea level rise, and acid deposition on the amount of DOM released from soil samples. DBP formation potentials (DBPFPs) were obtained to assess the effect of extreme weather events on DBP formation and drinking water quality. The results demonstrated that the dissolved organic carbon (DOC) and carbonaceous DBP levels increased with increasing temperature in a dry (drought) scenario. Regardless of the watershed from which a soil sample was obtained and the incubation temperature during rewetting or chlorination processes, the DOC and carbonaceous DBP levels also increased with increasing temperature. Brominated DBP formation was increased when bromide was present during the rewetting of soil, indicating the effect of sea level rise. When bromide was present during the chlorination of water for DBPFP tests, only the level of brominated DBPs increased. Acid deposition had various effects under different weather conditions. The results of heavy rainfall simulations suggested that water quality deteriorates at the beginning of an extreme rainfall event. Abundant DOM was washed out of soil, leading to a peak in the DBPFP level. The level of DOM in seepage water was less than that of the surface runoff water during rainfall. The situation was more severe when the rainfall came after a long drought and the drought–rewetting cycle effect occurred.
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26077. 题目: Potential of combined advanced oxidation - biological process for cost-effective organic matters removal in reverse osmosis concentrate produced from industrial wastewater reclamation: Screening of AOP pre-treatment technologies
文章编号: N19111005
期刊: Chemical Engineering Journal
作者: Q.Q. Cai, M.Y. Wu, R. Li, S.H. Deng, B.C.Y. Lee, S.L. Ong, J.Y. Hu
更新时间: 2019-11-10
摘要: While reverse osmosis (RO) technology is playing an important role in industrial wastewater reclamation, safe and cost-effective RO concentrate (ROC) disposal becomes challenging due to high levels of organic pollutants. The present study assessed the feasibility of combined advanced oxidation – biological process for organics removal in real ROC. Four advanced oxidation processes (AOPs) were evaluated for ROC pre-treatment, including UV/H₂O₂, UV/Persulfate (PS), Fenton and Fluidized bed reactor (FBR)-Fenton processes. Based on the results of process optimization and cost evaluation, FBR-Fenton was identified as the most cost-effective pre-treatment technology with a chemical cost of S$0.519/m³. Under the optimum operating conditions with 10mM H₂O₂, 1.25mM Fe²⁺, pH 3 and HRT of 1 hour, continuous FBR-Fenton process increased the BOD₅/COD ratios in ROC by 4.2-10.0 times, while the COD removal efficiency was in the range of 30.9-59.8%. A biological activated carbon (BAC) column with EBCT of 120min was combined with FBR-Fenton for continuous treatment of ROC. Over the 120-day operation, the combined system performed consistent organics removal in ROC with an average COD removal efficiency of 69%. The average effluent COD level in ROC was observed to be 26mg/L. Both LC-OCD data and fluorescence EEM spectra suggested humic substances to be the dominant organic species in ROC, FBR-Fenton could achieve significant humic substances removal and biodegradability enhancement in ROC. High-throughput sequencing demonstrated Planctomycetes to be top dominant phylum in BAC media with high salinity influent, and FBR-Fenton process promoted its proliferation for higher COD removal efficiency in ROC.
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26078. 题目: Application of co-composted biochar significantly improved plant-growth relevant physical/chemical properties of a metal contaminated soil
文章编号: N19111004
期刊: Chemosphere
作者: Manuel Teodoro, Lukáš Trakal, Brett N. Gallagher, Pavel Šimek, Petr Soudek, Micheal Pohořelý, Luke Beesley, Lukáš Jačka, Martin Kovář, Samar Seyedsadr, Dinesh Mohan
更新时间: 2019-11-10
摘要: A woody-biochar was added to waste biomass during a composting process. The resulting compost-char was amended to a metal contaminated soil and two plant species, L. perenne and E. sativa, were grown in a pot experiment to determine 1) plant survival and stress factors, 2) uptake of metals to plants and, 3) chemical characteristics of sampled soils and pore waters. Compost supplemented with biochar after the composting process were also tested, as well as a commercially available compost, for comparison.Co-composting with biochar hastened the composting process, resulting in a composite material of reduced odour, increased maturity, circum-neutral pH and increased moisture retention than compost (increase by 3% of easily removable water content).When amended to the soil, CaCl₂ extractable and pore water metals s were reduced by all compost treatments with little influence of biochar addition at any tested dose. Plant growth success was promoted furthest by the addition of co-composted biochar to the test soil, especially in the case of E. sativa. For both tested plant species significant reductions in plant metal concentrations (e.g. 8-times for Zn) were achieved, against the control soil, by compost, regardless of biochar addition.The results of this study demonstrate that the addition of biochar into the composting process can hasten the stability of the resulting compost-char, with more favourable characteristics as a soil amendment/improver than compost alone. This appears achievable whilst also maintaining the provision of available nutrients to soils and the reduction of metal mobility, and improved conditions for plant establishment.
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26079. 题目: Effects of Walnut Leaves Biochars on Lead and Zinc Fractionation and Phytotoxicity in a Naturally Calcareous Highly Contaminated Soil
文章编号: N19111003
期刊: Water, Air, & Soil Pollution
作者: Parvin Kabiri, Hamidreza Motaghian, Alireza Hosseinpur
更新时间: 2019-11-10
摘要: The aim of this study was to investigate the impact of incorporating Walnut leaves (WL) and their biochars produced at three temperatures (200, 400, and 600 °C) on fractionation, availability and maize indices in a naturally calcareous highly contaminated soil of Central Iran. A pot experiment was conducted considering soils treated with 0, 0.5, 1, and 2% (w/w) of WL and their derived biochars. After maize (Zea mays L.) planting, shoot and root dry matter and Pb and Zn concentration in shoots and roots and DTPA-extractable and fractions of Zn and Pb in soils were determined. Results showed showed that biochar amendments substantially modified the partitioning of Zn and Pb from easily available forms to less available forms. The results showed that DTPA-extractable of Zn and Pb and their bioaccumulation were reduced upon the addition of biochars produced at different temperatures and application rates in a calcareous soil. Treating soil with 2% biochar produced at 600 °C increased significantly shoot and root dry matter by 131.4% and 116.7%, respectively and reduced the bioavailability of Zn and Pb (DTPA-TEA extraction) by 49.1%, and 34.9%, respectively (P < 0.05) in comparison to the control. Therefore, biochars were able to reduce metals contamination in treatments and increase maize dry matter. Biochar decreased Zn and Pb concentration in plant tissues and promoted gradual maize growth responses through changing metals fractions. Therefore, biochar as a sorbent for contaminants can assist in maize to mitigate and phytostabilize Zn and Pb in highly contaminated soils.

26080. 题目: Biochar suppresses N 2 O emissions and alters microbial communities in an acidic tea soil
文章编号: N19111002
期刊: Environmental Science and Pollution Research
作者: Ningguo Zheng, Yongxiang Yu, Wei Shi, Huaiying Yao
更新时间: 2019-11-10
摘要: Biochar has been considered as a promising soil amendment for improving fertility and mitigating N₂O emission from the arable land. However, biochar’s effectiveness in acidic tea soil and underlying mechanisms are largely unknown. We conducted a short-term microcosm experiment using two biochars (1% w/w, LB, generated from legume and NLB, non-legume biomass, respectively) to investigate the effects of biochar amendments on soil chemical properties, N₂O emission, and microbial community in an acidic soil. Soil and headspace gas samples were taken on 1, 10, and 30 day’s incubation. Biochar amendment increased soil pH and DOC, however, significantly reduced soil inorganic N. Both biochars at ~ 1% addition had little effect on microbial CO₂ respiration but suppressed soil N₂O emission by ~ 40% during the incubation. The divergence in N₂O efflux rates between soils with and without biochar addition aligned to some degree with changes in soil pH, inorganic N, and dissolved organic C (DOC). We also found that biochar addition significantly modified the fungal community structure, in particular the relative abundance of members of Ascomycota, but not the bacterial community. Furthermore, the copy number of nosZ, the gene encoding N₂O reductase, was significantly greater in biochar-amended soils than the soil alone. Our findings contribute to better understanding of the impact of biochar on the soil chemical properties, soil N₂O emission, and microbial community and the consequences of soil biochar amendment for improving the health of acidic tea soil.