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13161. 题目: Remediation of heavy metal contaminated soils by biochar: Mechanisms, potential risks and applications in China
文章编号: N19061305
期刊: Environmental Pollution
作者: Lizhi He, Huan Zhong, Guangxia Liu, Zhongmin Dai, Philip C. Brookes, Jianming Xu
更新时间: 2019-06-13
摘要: There are global concerns about heavy metal (HM) contamination in soils, which in turn has produced an increased demand for soil remediation. Biochar has been widely documented to effectively immobilize metals in contaminated soils and has received increasing attention for use in soil remediation. Here, we review recent progresses in understanding metal-biochar interactions in soils, potential risks associated with biochar amendment, and application of biochar in soil remediation in China. These recent studies indicate that: (1) the remediation effect depends on the characteristics of both biochar and soil and their interactions; (2) biochar applications could decrease the mobility/bioavailability of HMs in soils and HM accumulation in plants; and (3) despite its advantages, biochar applications could pose ecological and health risks, e.g., by releasing toxic substances into soils or by inhalation of biochar dust. Research gaps still exist in the development of practical methods for preparing and applying different biochars that target specific HMs. In the future, the long term effects and security of biochar applications on soil remediation, soil organisms and plant growth need to be considered.
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13162. 题目: The global warming potential of straw-return can be reduced by application of straw-decomposing microbial inoculants and biochar in rice-wheat production systems
文章编号: N19061304
期刊: Environmental Pollution
作者: Yuchun Ma, De Li Liu, Graeme Schwenke, Bo Yang
更新时间: 2019-06-13
摘要: Straw-return methods that neither negatively impact yield nor bring environmental risk are ideal patterns. To attain this goal, it is necessary to conduct field observation to evaluate the environmental influence of different straw-return methods. Therefore, we conducted a 2-year field study in 2015–2017 to investigate the emissions of methane (CH4) and nitrous oxide (N2O) and the changes in topsoil (0–20 cm) organic carbon (SOC) density in a typical Chinese rice-wheat rotation in the Eastern China. These measurements allowed a complete greenhouse gas accounting (net GWP and GHGI) of five treatments including: FP (no straw, plus fertilizer), FS (wheat straw plus fertilizer), FB (straw-derived biochar plus fertilizer), FSDI (wheat straw with straw-decomposing microbial inoculants plus fertilizer) and CK (control: no straw, no fertilizer). Average annual SOC sequestration rates were estimated to be 0.20, 0.97, 1.97 and 1.87 t C ha−1 yr−1 (0–20 cm) for the FP, FS, FB and FSDI treatments respectively. Relative to the FP treatment, the FS and FSDI treatments increased CH4 emissions by 12.4 and 17.9% respectively, but decreased N2O emissions by 19.1 and 26.6%. Conversely, the FB treatment decreased CH4 emission by 7.2% and increased N2O emission by 10.9% compared to FP. FB increased grain yield, but FS and FSDI did not. Compared to the net GWP (11.6 t CO2-eq ha−1 yr−1) and GHGI (1.20 kg CO2-eq kg−1 grain) of FP, the FS, FB and FSDI treatments reduced net GWP by 12.6, 59.9 and 34.6% and GHGI by 10.5, 65.8 and 37.7% respectively. In rice-wheat systems of eastern China, the environmentally beneficial effects of returning wheat straw can be greatly enhanced by application of straw-decomposing microbial inoculants or by applying straw-derived biochar.
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13163. 题目: Metal sorption by biochars: A trade-off between phosphate and carbonate concentration as governed by pyrolysis conditions
文章编号: N19061303
期刊: Journal of Environmental Management
作者: R. Van Poucke, S. Allaert, Y.S. Ok, M. Pala, F. Ronsse, F.M.G. Tack, E. Meers
更新时间: 2019-06-13
摘要: Three feedstocks, pine wood, grass and cow manure, were pyrolyzed under various conditions and tested on their ability to sorb metals in aquatic systems. The feedstocks were pyrolyzed at 2 different temperatures (350 °C and 550 °C) and 2 different residence times (10 and 60 min) and resulting biochars were assessed on their capability to immobilize Pb, Cu, Cd and Zn.Manure-based chars, and to a lesser extent grass-based chars, featured high concentrations of phosphates and carbonates. These anions play an important role in metal sorption because they form insoluble complexes with the metals. Washing reduced the concentration of these anions, leading to a reduced sorption of metals by the biochar.The carbonate concentration on the biochars’ surface increased at higher reactor temperature and longer residence times. The opposite trend was observed for the phosphate concentration and the cation exchange capacity. Accordingly, the optimal temperature-residence time combination for sorption was a trade-off between these properties. Biochar produced from cow manure and pyrolyzed at 550 °C for 10 min showed the best sorption for all metals considered.

13164. 题目: Synthesis of a novel ternary HA/Fe-Mn oxide-loaded biochar composite and its application in cadmium(II) and arsenic(V) adsorption
文章编号: N19061302
期刊: Journal of Environmental Sciences
作者: Jianhua Guo, Changzhou Yan, Zhuanxi Luo, Hongda Fang, Shugang Hu, Yinglan Cao
更新时间: 2019-06-13
摘要: Cadmium (Cd) and arsenic (As) are two of the most toxic elements. However, the chemical behaviors of these two elements are different, making it challenging to utilize a single adsorbent with high adsorption capacity for both Cd(II) and As(V) removal. To solve this problem, we synthesized HA/Fe-Mn oxide-loaded biochar (HFMB), a novel ternary material, to perform this task, wherein scanning electron microscopy (SEM) combined with EDS (SEM-EDS) was used to characterize its morphological and physicochemical properties. The maximum adsorption capacity of HFMB was 67.11 mg/g for Cd(II) and 35.59 mg/g for As(V), which is much higher compared to pristine biochar (11.06 mg/g, 0 mg/g for Cd(II) and As(V), respectively). The adsorption characteristics were investigated by adsorption kinetics and the effects of the ionic strength and pH of solutions. X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FT-IR) revealed that chelation and deposition were the adsorption mechanisms that bound Cd(II) to HFMB, while ligand exchange was the adsorption mechanism that bound As(V).
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13165. 题目: EDTA functionalized magnetic biochar for Pb(II) removal: adsorption performance, mechanism and SVM model prediction
文章编号: N19061301
期刊: Separation and Purification Technology
作者: Mingrun Li, Dong Wei, Ting Liu, Yingrui Liu, Liangguo Yan, Qin Wei, Bin Du, Weiying Xu
更新时间: 2019-06-13
摘要: It is beneficial to establish a rapid prediction approach of sorption by considering various operating variables that can greatly reduce workload and minimize operational costs. In the present study, Pb(II) sorption onto synthetic biochar (BC), magnetic biochar (M-BC) and EDTA functionalized magnetic biochar (EDTA-M-BC) were comparative investigated in view of adsorption factors, adsorption kinetics and adsorption isotherm. Support vector machine (SVM) model was proposed to predict the adsorption performance by considering various operating variables. It was found that the BET surface areas of BC, M-BC and EDTA-M-BC was 499.2, 255.7 and 57.5 m2/g, respectively, and the majority of pores in the BC samples were mesoporous. The Pb(II) sorption processes by three kinds of BCs were well fitted to pseudo-second-order kinetic model and Langmuir model. According to zeta potential and X-ray photoelectron spectroscopy (XPS) analysis, the adsorption mechanism for Pb(II) adsorbed onto BCs were mainly attributed to electrostatic interaction and chemical complexation. The 10-fold cross-validation was performed to estimate SVM validity. The predication results showed approximately 99.4% accuracy for test datasets and 100% accuracy for experiment data. Thus, SVM could be a reliable accurate estimation method to predict adsorption performance.
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13166. 题目: Impact of organic matter amendments on soil and tree water status in a California orchard
文章编号: N19061211
期刊: Agricultural Water Management
作者: Hannah C. Lepsch, Patrick H. Brown, Caitlin A. Peterson, Amélie C.M. Gaudin, Sat Darshan S. Khalsa
更新时间: 2019-06-12
摘要: Permanent crops like almond (Prunus dulcis) require significant water inputs for economic yields and long-term productivity. This demand creates a challenge in drought-prone regions like California. Use of organic matter amendments (OMA) can improve water use efficiency by conserving soil moisture and reducing tree water stress. The majority of almond orchards in California are no-till with irrigation targeted on a narrow tree berm where OMA is applied as surface mulch. We examined the effects of composted dairy manure (CM) and the timing of its application on soil moisture, soil water retention and tree water status in a young orchard planted in 2014. Treatments including Fall-applied CM (October 2015 and 2016), Spring-applied CM (April 2016 and 2017) and an unamended control were monitored during the 2016 and 2017 growing seasons. Fall-applied CM was more readily incorporated in soil organic matter of the 0–60 cm rooting zone as evidenced by significantly greater soil organic carbon (SOC) for Fall versus Spring-applied CM in 2016 (p < 0.05). Fall-applied CM significantly increased soil volumetric water content (VWC) by 22% from 0 to 150 cm depth during the driest period of year one and tended to make midday stem water potential (SWP) less negative relative to the control. Fall-applied CM tended to increase VWC in 2017, but treatment differences were no longer significant. Differences in VWC and SWP between Fall-applied CM and the control were most apparent at low VWC (<10%). Two years of Fall-applied CM increased soil water retention between 0 to ˜100 kPa at 0–10 cm depth by 13% compared to the control. These results demonstrate Fall-applied CM was more effective at enhancing soil moisture retention and reducing tree water stress compared to Spring-applied CM. We also conclude OMA use may buffer against periods of limited water supply for young trees.

13167. 题目: The response of microbial composition and enzyme activities to hydrological gradients in a riparian wetland
文章编号: N19061210
期刊: Journal of Soils and Sediments
作者: Lixia Wang, Baixing Yan, Shiv O. Prasher, Yang Ou, Yu Bian, Hu Cui
更新时间: 2019-06-12
摘要: Purpose: Hydrological condition is one of the important factors impacting microbial structure in riparian wetlands. However, how these microbial communities respond to different hydrological gradients through environmental factors remains uncertain. The main objective of this research was to identify soil microbial community structure under various water levels in a wetland and provide instructive information for assessing wetland function. Materials and methods: Soil samples were collected from sampling plots under different hydrological conditions. Soil parameters, including total nitrogen (TN), available nitrogen (AN), total phosphorus (TP), available phosphorus (AP), soil organic carbon (SOC), and dissolved organic carbon (DOC), were utilized to identify the effect of different hydrological conditions on soil properties. The quantity and abundance of phospholipid fatty acid (PLFA) and enzyme activities (alkaline phosphatase, urease, and invertase) were utilized to evaluate variation of microbial community. Results and discussion: The PLFA of bacteria, fungi, and actinomycetes accounted for 80.64–85.09%, 9.09–12.23%, and 5.06–6.02% of the total PLFA in wetland soil, respectively. Soil water content showed significant correlation with microbial PLFA and enzyme activities. Long-term inundation led to substantial alteration in the microbial biomass and structure. The redundancy analysis (RDA) identified that AN and AP were the critical factors impacting the structure of microbial community, and AP and SOC were principal factors to soil enzyme activities. Conclusions: Soil water content was the principal controlling factor in the formation of special environment for microbial community. The perennial flooded condition stimulated the increase of bacteria, fungi, and actinomycetes through changing AN and AP levels. Thus, the relation between microbial community and hydrological gradients was significantly impacted by soil nutrition.

13168. 题目: Uptake and transport of Pb across the iron plaque of waterlogged dropwort ( Oenanthe javanica DC . ) based on micro-XRF and XANES
文章编号: N19061209
期刊: Plant and Soil
作者: Jian Liu, Liqiang Luo
更新时间: 2019-06-12
摘要: Background and aim: Iron plaque at the soil-root interface is a key position for uptake of heavy metals by plants. Exploring iron plaque’s role in Pb uptake by edible vegetable roots aids understanding Pb uptake mechanisms and developing methods to reduce Pb accumulation. Methods: Soil and plant Pb contents were determined. Micro X-ray fluorescence (micro-XRF) determined Fe and Pb distributions in waterlogged and terrestrial Oenanthe javanica DC. roots, and X-ray absorption near-edge spectroscopy (XANES) identified Pb speciation in bulk soil, rhizosphere soil and plant tissues. Results: Waterlogged O. javanica accumulated more Pb and exhibited a higher Pb transfer factor than terrestrial O. javanica. In waterlogged O. javanica, the iron plaque and epidermis contained the most Fe, while the root vasculature contained the most Pb. In terrestrial O. javanica roots, Fe and Pb had similar distributions. Bulk and rhizosphere soils contained different Pb species, and rhizosphere soil had Pb-humate. For iron plaque, a new Pb complex, Pb-ferrihydrite, was identified. Biologically important groups bound (-S, -COO) and precipitated (-PO4) Pb were identified in plants. Conclusions: Waterlogged O. javanica root iron plaque and humic acid increase Pb uptake and accumulation. Thus, avoiding O. javanica root iron plaque formation (dry land growth) and growing in low-humic soil reduce Pb uptake and entry into the food chain.

13169. 题目: Response of soil C:N:P stoichiometry, organic carbon stock, and release to wetland grasslandification in Mu Us Desert
文章编号: N19061208
期刊: Journal of Soils and Sediments
作者: Huan He, Guotong Xia, Wenjin Yang, Yunpeng Zhu, Guodong Wang, Weibo Shen
更新时间: 2019-06-12
摘要: Purpose: Wetlands in Mu Us Desert have severely been threatened by grasslandification over the past decades. Therefore, we studied the impacts of grasslandification on soil carbon (C):nitrogen (N):phosphorus (P) stoichiometry, soil organic carbon (SOC) stock, and release in wetland-grassland transitional zone in Mu Us Desert. Materials and methods: From wetland to grassland, the transition zone was divided into five different successional stages according to plant communities and soil water conditions. At every stage, soil physical and chemical properties were determined and C:N:P ratios were calculated. SOC stock and soil respirations were also determined to assess soil carbon storage and release. Results and discussion: After grasslandification, SOC contents of top soils (0–10 cm) decreased from 100.2 to 31.79 g kg−1 in June and from 103.7 to 32.5 g kg−1 in October; total nitrogen (TN) contents of top soils (0–10 cm) decreased from 3.65 to 1.85 g kg−1 in June and from 6.43 to 3.36 g kg−1 in October; and total phosphorus (TP) contents of top soils (0–10 cm) decreased from 179.4 to 117.4 mg kg−1 in June and from 368.6 to 227.8 mg kg−1 in October. From stages Typha angustifolia wetland (TAW) to Phalaris arundinacea L. (PAL), in the top soil (0–10 cm), C:N ratios decreased from 32.2 to 16.9 in June and from 19.0 to 11.8 in October; C:P ratios decreased from 1519.2 to 580.5 in June and from 19.0 to 11.8 in October; and N:P ratios decreased from 46.9 to 34.8 in June and changed from 34.9 to 34.0 in October. SOC stock decreased and soil respiration increased with grasslandification. The decrease of SOC, TN, and TP contents was attributed to the reduction of aboveground biomass and mineralization of SOM, and the decrease of soil C:N, C:P, and N:P ratios was mainly attributed to the faster decreasing speeds of SOC than TN and TP. The reduction of aboveground biomass and increased SOC release led by enhanced soil respiration were the main reasons of SOC stock decrease. Conclusions: Grasslandification led to lowers levels of SOC, TN, TP, and soil C:N, C:P, and N:P ratios. Grasslandification also led to higher SOC loss, and increased soil respiration was the main reason. Since it is difficult to restore grassland to original wetland, efficient practices should be conducted to reduce water drainage from wetland to prevent grasslandification.

13170. 题目: Vegetation restoration stimulates soil carbon sequestration and stabilization in a subtropical area of southern China
文章编号: N19061207
期刊: CATENA
作者: Xiang Gu, Xi Fang, Wenhua Xiang, Yelin Zeng, Shiji Zhang, Pifeng Lei, Changhui Peng, Yakov Kuzyakov
更新时间: 2019-06-12
摘要: Vegetation restoration affects the stability of soil organic carbon (SOC) by changing the composition of soil carbon pools, including active carbon (Ca), the labile pool of SOC; slow carbon (Cs), the physically stabilized pool of SOC; and resistant carbon (Cr), the chemically stabilized pool of SOC. The aims of this study were to determine how SOC pools changed during restoration of a subtropical forest and to what extent vegetation characteristics and soil properties affected the changes in SOC pools. Soil samples were collected to 40 cm in four plant communities along a restoration chronosequence: scrub-grassland (4–5 years), shrubs (10–12 years), coniferous and broadleaved mixed forest (45–46 years), and evergreen broadleaved forest (90–91 years). Laboratory incubations were used to measure CO2 production during SOC mineralization, and acid hydrolysis was used to measure Cr. The CO2 production and Cr data were fitted to a three-component first-order kinetic model to determine the Ca and Cs. Pearson's correlations, stepwise multiple line regressions, and variation partitioning analysis were used to determine the key factors that affected SOC pools. The results showed that vegetation restoration increased the contents of SOC from 1.67 to 47.6 g kg−1, Ca from 0.03 to 0.35 g kg−1, Cs from 1.32 to 24.5 g kg−1, and Cr from 0.33 to 22.8 g kg−1. During vegetation restoration, the increase in SOC was primarily due to carbon (C) stored in stable pools (i.e., Cs or Cr), and the portion of Cr in total SOC increased markedly from 18.5 to 56.3%. Fine root biomass was the primary driver that controlled SOC pools during vegetation restoration. The C/N ratio of litter had a greater effect on Ca and Cs than that of other factors, whereas the soil clay content contributed secondarily to Cr. The results suggest that vegetation restoration increases not only the amounts of SOC, Ca, Cs, and Cr but also the stability of the SOC pool in subtropical soil. The relatively rapid increases in Cs and Cr following vegetation restoration played a crucial role in C sequestration. Therefore, strong measures to preserve natural forests and facilitate vegetation restoration should be the primary approach to increase long-term soil C sequestration in this region.

13171. 题目: New method for algae comprehensive utilization: algae-derived biochar enhances algae anaerobic fermentation for short-chain fatty acids production
文章编号: N19061206
期刊: Bioresource Technology
作者: Xu Duan, Yunzhi Chen, Yuanyuan Yan, Leiyu Feng, Yinguang Chen, Qi Zhou
更新时间: 2019-06-12
摘要: Interest in the resource utilization of algae has gradually increased due to the frequent occurrence of harmful algal blooms. Here, biochar derived from algae was applied to algae anaerobic fermentation for short-chian fatty acids (SCFAs) production. In the presence of algae-derived biochar, the concentration of SCFAs within 4 d (4334 mg COD/L) was approximately doubled compared to the control (2016 mg COD/L), and the fermentation time for maximal SCFAs yield was shortened. Biochar improved the disruption of algae to release more intracellular macromolecular organics. Altering algae hydrolysis, the activity of hydrolase and the contents of functional gene were advantageous to SCFAs accumulation by providing more micromolecular organics in the presence of biochar. Additionally, the relative abundance and survival of acid-forming bacteria were enhanced significantly. Furthermore, biochar accelerated the electron transport and energy synthesis in the biological system, driving the biological reactions that allow microorganisms to function and life to flourish.
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13172. 题目: Insight into the fenton-induced degradation process of extracellular polymeric substances (EPS) extracted from activated sludge
文章编号: N19061205
期刊: Chemosphere
作者: Bin-Bin Wang, Xiang Shi, Xue-Ting Liu, Jin-Te Zou, Hui-Juan Li, Dang-Cong Peng, Feng He
更新时间: 2019-06-12
摘要: Although EPS in microbial aggregates are importance in successful implementation of biological wastewater treatment systems, they also exhibit detrimental role on certain circumstance, such as excess sludge dewatering. Extensive efforts have been put into the disruption of EPS for improving the dewaterability of excess sludge and Fenton's reagent treatment has been demonstrated to be a very promising sludge conditioning method for EPS destruction. However, the information regarding detailed degradation process of EPS during Fenton's reagent treatment is limited. In this study, EPS were extracted from activated sludge and treated with different concentrations of Fenton's reagent. The physicochemical characteristic changes of EPS under different treatment were investigated in terms of components, EEM, molecular weight (MW), UV-Vis and FTIR. The results showed that EPS were prone to be disintegrated, but hard to be fully mineralized. Humic substances in EPS were more resistant to Fenton's reagent than other components. Low MW components of EPS were preferentially degraded prior to the disruption of high MW components. Besides, the disintegration of EPS into lower MW ones was accompanied by the formation of higher MW compounds caused by the bridge interaction of Fe ions. The cleavage of protein's backbone in EPS was mainly through destruction of amide II (N–H and C–N) in –CO–NH–. Fenton's reagent treatment also led to a significant increase of oxygen-containing functional groups in EPS molecules. This paper may pave a path to deeply understand the mechanisms of dewatering improvements of excess sludge by Fenton's conditioning.
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13173. 题目: Mercury as a proxy for volcanic emissions in the geologic record
文章编号: N19061204
期刊: Earth-Science Reviews
作者: Stephen E. Grasby, Theodore R. Them, Zhuoheng Chen, Runsheng Yin, Omid H. Ardakani
更新时间: 2019-06-12
摘要: Large igneous province (LIP) eruptions are increasingly considered to have driven mass extinction events throughout the Phanerozoic; however, uncertainties in radiometric age dating of LIP materials, along with difficulty in accurate age dating of sedimentary rocks that record the environmental and biological history of our planet, create inherent uncertainties in any linkage. As such, there is interest in using geochemical proxies to fingerprint periods of major volcanism in the sedimentary record (termed here LIP marks). The use of sedimentary mercury (Hg) contents has been suggested to be the best tool to accomplish this goal, and recent work is reviewed here. Studies to-date show that most extinction events, ocean anoxic events, and other environmental crises through the Phanerozoic have an associated sedimentary Hg anomaly. It remains unclear though if each Hg anomaly is truly a signature of massive volcanism, or if it is controlled by local or regional processes. As Hg has a strong affinity to organic matter (OM), normalisation with total organic carbon (TOC) has been used to assess anomalies. The measurement of TOC has been fraught with error throughout many studies, leaving some claimed Hg/TOC anomalies questionable. Normalisation by other elements that can affect Hg sequestration, such as Al and S, are less common but warrant further investigation. Stable isotope systematics of Hg have helped to further clarify the origin of Hg spikes, and clearly show that not all Hg anomalies are directly related to volcanism. Although a promising tool, the Hg proxy requires more refinement to accurately understand the nuances of an Hg anomaly in the rock record.

13174. 题目: Distribution, availability and translocation of heavy metals in soil-oilseed rape (Brassica napus L.) system related to soil properties
文章编号: N19061203
期刊: Environmental Pollution
作者: Xuerui Cao, Xiaozi Wang, Wenbin Tong, Hanumanth Kumar Gurajala, Min Lu, Yasir Hamid, Ying Feng, Zhenli He, Xiaoe Yang
更新时间: 2019-06-12
摘要: Heavy metals contamination in agricultural soil has become a worldwide problem, and soil characteristics modulate metal availability in soils. Four field experiments were conducted simultaneously to evaluate concentration and distribution of cadmium (Cd) and lead (Pb) in 39 oilseed rape cultivars at four agricultural locations with different contamination levels of Cd and Pb, as well as the influence of soil characteristics together with soil total and bioavailable Cd and Pb concentration on metal transfer from soil to oilseed rape. Shoot concentrations of Cd and Pb in oilseed rape cultivars ranged from 0.09 to 3.18 and from 0.01 to 10.5 mg kg−1 across four sites. For most cultivars, Cd concentration in root or shoot were higher than pod and lowest in seed, while the highest Pb concentration was observed in root followed by shoot and seed. Stepwise multiple linear regression analysis allows for a better estimation of Cd and Pb concentration in oilseed rape while taking soil properties into consideration. The results demonstrated that Cd and Pb concentration in oilseed rape were correlated with soil organic matter (OM), cation exchange capacity (CEC), available phosphorus (AP), available potassium (AK), sand, soil total and available Cd and Pb concentration, and R2 varied from 0.993 to 0.999 (P < 0.05). The Cd and Pb levels found in oilseed rape indicated its phytoextraction potential for Cd and Pb co-contaminated agricultural soils in winter without stopping agricultural activities.
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13175. 题目: Adsorption of 17β-estradiol from aqueous solution by raw and direct/pre/post-KOH treated lotus seedpod biochar
文章编号: N19061202
期刊: Journal of Environmental Sciences
作者: Ni Liu, Yun-guo Liu, Guang-ming Zeng, Ji-lai Gong, Xiao-fei Tan, Jun-Wen, Shao-bo Liu, Lu-hua Jiang, Mei-fang Li, Zhi-hong Yin
更新时间: 2019-06-12
摘要: Five biochars derived from lotus seedpod (LSP) were applied to examine and compare the adsorption capacity of 17β-estradiol (E2) from aqueous solution. The effect of KOH activation and the order of activation steps on material properties were discussed. The effect of contact time, initial concentration, pH, ionic strength and humic acid on E2 adsorption were investigated in a batch adsorption process. Experimental results demonstrated that the pseudo-second-order model fitted the experimental data best and that adsorption equilibrium was reached within 20 hr. The efficiency of E2 removal increased with increasing E2 concentration and decreased with the increase of ionic strength. E2 adsorption on LSP-derived biochar (BCs) was influenced little by humic acid, and slightly affected by the solution pH when its value ranged from 4.0 to 9.0, but considerably affected at pH 10.0. Low environmental temperature is favorable for E2 adsorption. Chemisorption, π–π interactions, monolayer adsorption and electrostatic interaction are the possible adsorption mechanisms. Comparative studies indicated that KOH activation and the order of activation steps had significant impacts on the material. Post-treated biochar exhibited better adsorption capacity for E2 than direct treated, pre-treated, and raw LSP biochar. Pyrolyzed biochar at higher temperature improved E2 removal. The excellent performance of BCs in removing E2 suggested that BCs have potential in E2 treatment and that the biochar directly treated by KOH would be a good choice for the treatment of E2 in aqueous solution, with its advantages of good efficiency and simple technology.
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13176. 题目: Toxic effects and metabolic fate of carbamazepine in diatom Navicula sp. as influenced by humic acid and nitrogen species
文章编号: N19061201
期刊: Journal of Hazardous Materials
作者: Tengda Ding, Kunde Lin, Bo Yang, Menting Yang, Juying Li
更新时间: 2019-06-12
摘要: Carbamazepine (CAB) is a commonly detected pharmaceutical in the surface waters. In the present study, we evaluated the effect of humic acid (HA) and nitrogen species on the toxicity of CAB in a typical diatom Navicula sp., and its metabolic fate. The Navicula sp. showed a high sensitivity to CAB (72 h EC50 = 0.179 mg L-1). The addition of HA (< 30 mg L-1) and ammonium could promote the growth of Navicula sp. during 6 d of exposure to CAB. CAB underwent rapid dissipation in the algal culture. The degradation of CAB in Navicula sp. cultures was significantly increased by the addition of HA and higher HA contents caused more degradation of CAB. Degradation and accumulation of CAB in Navicula sp. were significantly inhibited by ammonium. Five metabolites were found and possible degradation pathways of CAB in the algal cell were proposed. Methoxylation, demethylation, glucuronidation and hydroxylation contributed to CAB transformation in the algal cell.
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13177. 题目: Abiotic Formation of Humic-Like Substances through Freezing-Accelerated Reaction of Phenolic Compounds and Nitrite
文章编号: N19061110
期刊: Environmental Science & Technology
作者: Dae Wi Min, Kitae Kim, Ka Hei Lui, Bomi Kim, Sunghwan Kim, Jaeweon Cho, Wonyong Choi
更新时间: 2019-06-11
摘要: A previously unknown abiotic humification pathway which is highly accelerated in frozen solution containing phenolic compounds and nitrite was investigated and proposed. The production of humic-like acids (HLA) and fulvic-like acids (FLA) was observed in the frozen solution (−20 °C) whereas it was negligible in aqueous solution (20 °C). Inorganic nitrogen was transformed into organic nitrogen during the humification process. Mass spectrometry (MS) and elemental analyses, including pyrolysis-GC/MS and FT-ion cyclotron resonance/MS, showed that humification products (HLA and FLA) have chemical structures and compositions similar to nature humic substances. The enhanced humification reaction could be attributed to the freeze-concentration effect, whereby nitrite ions in the unfrozen grain boundary region are transformed into nitrosonium ions which oxidize phenols to phenolic radicals. Confocal Raman microscopy confirmed that catechol and nitrite ions are preferentially concentrated at the ice grain boundary and electron paramagnetic resonance spectroscopic analysis of catechol/nitrite solution detected the phenolic radicals only in frozen solution, not in aqueous solution. The freezing-induced generation of phenolic radicals should lead to the formation of humic-like substances through polymerization. This study identifies and proposes a new humic formation pathway that might work as a model abiotic bottom-up mechanism in frozen environmental conditions.

13178. 题目: Pyrolysis of different biomass pre-impregnated with steel pickling waste liquor to prepare magnetic biochars and their use for the degradation of metronidazole
文章编号: N19061109
期刊: Bioresource Technology
作者: Yunqiang Yi, Guoquan Tu, Dongye Zhao, Pokeung Eric Tsang, Zhanqiang Fang
更新时间: 2019-06-11
摘要: In this study, Fenton-like catalysts (magnetic biochar) were synthesised by pyrolysis the different biomass pre-impregnated with steel pickling waste liquor. The results of degradation of metronidazole illustrated that the catalytic performance of magnetic biochar was significantly affected by biomass feedstocks. Electron spin resonance (ESR) and radical quenching experiments showed that the hydroxide radicals (•OH) were the key reactive oxygen species responsible for the metronidazole removal. Levels of •OH varied among different systems consistent with the removal of metronidazole. The activation of H2O2 by carbon-containing components and Fe species (Fe2O3 and Fe3O4) in magnetic biochar were confirmed to be less crucial to the degradation of metronidazole. Moreover, the Fe(II) (FeO) in magnetic biochar played the dominating role in degradation of metronidazole, and the Fe(II) content difference caused by biomass feedstocks was responsible for differences in the catalytic performance of different types of magnetic biochar.
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13179. 题目: Overcoming the instability of aerobic granular sludge under nitrogen deficiency through shortening settling time
文章编号: N19061108
期刊: Bioresource Technology
作者: Yunjun Yin, Fengyuan Liu, Lu Wang, Jian Sun
更新时间: 2019-06-11
摘要: This study investigated the short settling time strategy to overcome the instability of aerobic granular sludge (AGS) under nitrogen deficiency. AGS variations in its physical and chemical characteristics and microbial community were investigated. Results showed that nitrogen deficiency led to the instability of AGS, while short settling time strategy could overcome the instability of AGS under nitrogen deficiency. Extracellular polymeric substances (EPS), especially, the increased secretion of polysaccharide and proteins with amide III groups at the short settling time enhanced the granules stability under nitrogen deficiency. Unclassified_f_Microbacteriaceae shifted to be the major bacteria group at short settling time, along with the decrease of Meganema and Rhodobacter and the increase of Lysobacter, which may play an important role in enhancing AGS stability. Therefore, shortening settling time supports an effective strategy for applications of AGS under nitrogen deficiency.

13180. 题目: Novel lanthanum doped biochars derived from lignocellulosic wastes for efficient phosphate removal and regeneration
文章编号: N19061107
期刊: Bioresource Technology
作者: Qinyuan Xu, Zhongbing Chen, Zhengsong Wu, Fei Xu, Dongxu Yang, Qiang He, Guo Li, Yi Chen
更新时间: 2019-06-11
摘要: Phosphorus reduction from wastewater is vital to mitigate eutrophication of receiving waters. In this study, discarded lignocellulose biochar loaded with lanthanum (defined as La-biochar) was applied for phosphate adsorption. Based on the design of response surface methodology, La-biochar displayed a high phosphate adsorption capacity of 36.06 mg P/g, strong pH-compatibility from 3 to 12, favorable selectivity for phosphate among foreign ions (Cl-, SO42-, CO32-, HCO3- and NO3-), excellent reusability with 92.3% desorption efficiency and retained 85% adsorption capacity after five recycles. The adsorption law of La-biochar perfectly matched with the pseudo-second-order model and the Langmuir model. Moreover, real wastewater adsorption experiments indicated the removal of total phosphorus within 20 min. Ligand exchange, electrostatic attraction, and complexation mechanisms contributed to phosphate adsorption on La-biochar. Overall, the La-biochar material could be applied as a potential sustainable building block for the preconcentration of phosphorus for practical pollutant purification.
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