20年7月18日文獻情報
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本次文獻簡報涉及農業和森林集水區DOM的損失[1]，硝化+厭氧氨氧化去除廢水有機物[2]，矽包埋和鐵複合生物炭去除水中砷酸鹽[3]，載銀生物炭光催化降解亞甲基藍和抗菌[4]，水處理殘留體中有機質對吸附Pb的作用[5]，藻類有機質對含水層DOM衰減影響[6]，氣藏高原溼草甸土壤不穩定有機質組分對植物退化響應[7]，凋落物質量、土壤性質和微生物策略驅動土壤有機質礦化激發效應[8]，生物炭活化過硫酸鹽氧化改善廢水活性汙泥脫水性能[9]，極端降水條件下水葫蘆減少溶解有機氮含量[10]，磷通過與鈣離子的三元複合體與土壤有機質結合[11]，有機質組分對水泥固化鉛汙染土壤影響[12]，水熱碳輔助增強電化學降解2,4-二氯苯酚[13]，生物炭和植物修復礦井汙染物土壤[14]，NOM對微生物-水鐵礦還原Cd的影響[15]，沿海水域CDOM的光學特性[16]，生物炭改性黏土礦的飽和滲透性[17]，缺水盆地河流沉積物DOM的特徵與價值[18]，生物炭催化汙泥與稻殼供熱解[19]。
1. 題目: Losses of phosphorus, nitrogen, dissolved organic carbon and soil from a small agricultural and forested catchment in east-central Finland文章編號: N20071819
期刊: Agriculture, Ecosystems and Environment
作者: Mari Räty, Kirsi Järvenranta, Erkki Saarijärvi, Jari Koskiaho, Perttu Virkajärvi
更新時間: 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.
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2. 題目: Organic compounds evolution and sludge properties variation along partial nitritation and subsequent anammox processes treating reject water文章編號: N20071818
期刊: Water Research
作者: Weigang Wang, Hongchao Xie, Han Wang, Hao Xue, Junjie Wang, Mingda Zhou, Xiaohu Dai, Yayi Wang
更新時間: 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.
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3. 題目: Fabrication and evaluation of silica embedded and zerovalent iron composited biochars for arsenate removal from water文章編號: 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
更新時間: 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.
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4. 題目: Carbothermal synthesis of biochar-supported metallic silver for enhanced photocatalytic removal of methylene blue and antimicrobial efficacy文章編號: 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
更新時間: 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.
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5. 題目: Characteristics and mechanisms of Pb(II) sorption onto Fe-rich waste water treatment residue (WTR): A potential sustainable Pb immobilisation technology for soils文章編號: N20071815
期刊: Journal of Hazardous Materials
作者: Nina C. Finlay, Caroline L. Peacock, Karen A. Hudson-Edwards, Karen L. Johnson
更新時間: 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.
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6. 題目: Influence of algal organic matter on the attenuation of selected trace organic contaminants and dissolved organic matter in managed aquifer recharge: column studies文章編號: N20071814
期刊: Environmental Science: Water Research & Technology
作者: Jin Hyung Noh, Soo Hyun So, Jiwon Park, Sung Kyu Maeng
更新時間: 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.
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7. 題目: Response of soil labile organic carbon fractions and carbon-cycle enzyme activities to vegetation degradation in a wet meadow on the Qinghai–Tibet Plateau文章編號: N20071813
期刊: Geoderma
作者: Weiwei Ma, Guang Li, Jianghua Wu, Guorong Xu, Jiangqi Wu
更新時間: 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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8. 題目: Temporal dynamics of litter quality, soil properties and microbial strategies as main drivers of the priming effect文章編號: N20071812
期刊: Geoderma
作者: Nicolas Fanin, Gonzague Alavoine, Isabelle Bertrand
更新時間: 2020-07-18
摘要: The priming effect describes the change in the rate of soil organic matter (SOM) mineralisation due to the addition of fresh organic matter (FOM), and is thus central to the evaluation of carbon fluxes in terrestrial ecosystems. However, little is known about how litter quality interact with soil properties and microbial communities to explain the priming effect. Here, we provide new empirical evidence showing how litter, soil and microbial parameters control FOM and SOM decomposition. We monitored the kinetics of carbon fluxes over 202 days and at 23 dates after additions of two 13C-labelled plant litters of contrasted quality (nutrient-rich and labile litter [i.e., high quality] vs nutrient-poor and recalcitrant litter [i.e., low quality]) using four soil types originating from different ecosystems (forest, grassland, cropland and plantation). We found that the priming effect varied over time with: (i) an 'immediate' priming effect after the addition of high quality litter, which rapidly decreases when nitrogen is available; and (ii) a 'delayed' priming effect after the addition of low quality litter, which increases continuously when nitrogen is depleted. The 'immediate' priming was mainly related to the decomposition of accessible carbon compounds, whereas the 'delayed priming' was mainly related to the decomposition of recalcitrant carbon compounds. These results were linked to changes in microbial resource acquisition strategies as indicated by shifts in enzyme activities from hydrolytic to oxidative and nitrogen-related enzymes, therefore suggesting that two series of mechanisms act in succession at different time scales in relation to litter quality and nitrogen availability. Furthermore, our data demonstrate that incorporating carbon in the soil via the increase in soil microbial biomass can counterbalance carbon losses via priming effect. This highlights the importance to assess the balance between the carbon outputs and inputs to determine whether terrestrial ecosystems act as a sink or a source of carbon. We conclude that shifts in litter quality, nutrient availability and microbial resource acquisition strategies need to be taken into consideration for accurate assessment of the variability of the priming effect from the short to the long term.
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9. 題目: Insight into the improvement of dewatering performance of waste activated sludge and the corresponding mechanism by biochar-activated persulfate oxidation文章編號: N20071811
期刊: Science of the Total Environment
作者: Junyuan Guo, Xiaojuan Jia, Qifan Gao
更新時間: 2020-07-18
摘要: A novel activator, corn biochar, was produced to activate persulfate to dewater waste activated sludge (WAS). Results demonstrated that the biochar-activated persulfate oxidation can effectively improve the dewatering performance of WAS. After treating WAS by biochar-activated persulfate oxidation (biochar dosage: 2.1 g/L, persulfate concentration: 7.5 mM) at the original WAS pH, standardized-capillary suction time (SCST) increased to 4.21 times and moisture content (MC) decreased to 43.4%, indicating an excellent performance of WAS dewatering. The decrease of residual persulfate with the increasing biochar dosage during WAS dewatering process illustrated that the role of persulfate in improving WAS dewatering was because of the biochar activation. The behaviors of extracellular polymers (EPS) proved that the protein in tightly bound EPS (TB-EPS) linked to WAS dewatering, and its content significantly reduced to 10.5 mg/g-volatile solids (VS) after WAS treatment. Three-dimensional fluorescence spectroscopy for EPS once again proved that the disintegration of tryptophan protein and humic acid (hydrophobic organic substances in EPS) was responsible for the improvement of WAS dewatering. To sum up, the biochar-activated persulfate oxidation was a feasible application in improving WAS dewatering.
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10. 題目: Responses of phytoremediation in urban wastewater with water hyacinths to extreme precipitation文章編號: N20071810
期刊: Journal of Environmental Management
作者: Hongjie Qin, Muhe Diao, Zhiyong Zhang, Petra M. Visser, Yingying Zhang, Yan Wang, Shaohua Yan
更新時間: 2020-07-18
摘要: Climate change not only intensifies eutrophication and enhances the rainfall, but also elevates the contents of greenhouse gases, which can further increase the intensity and frequency of extreme precipitation events. The effectivity of phytoremediation of urban wastewaters by water hyacinths under an extreme rainfall event (up to 380 mm d−1) was investigated using self-designed fabrications with six flow rates (2–15 m3 d−1) in situ on pilot scale for 30 days. The results suggest that water hyacinths had high N and P removal capacities even under adverse conditions such as low dissolved oxygen concentrations (DO, <1 mg L−1) and high ammonium concentrations (NH4+-N, >7 mg L−1). Specifically, the highest removal yields of N and P were 13.14 ± 0.47 g N·m−2·d−1 and 2.12 ± 0.04 g P·m−2·d−1, respectively. The results indicate that water hyacinths can be used for water treatment to reduce the amounts of NH4+-N, dissolved organic nitrogen (DON) and phosphate (PO43−) even during extreme precipitation events. Moreover, DO increased due to wet deposition, runoff and surface flows during the extreme rainfall event, resulting in shifts between nitrification and denitrification processes which significantly altered nitrogen forms in urban wastewater. Results of this study suggest that water hyacinths could be recommended as a cost-effective and eco-friendly technology for urban wastewater phytoremediation in areas suffering from frequent extreme precipitation events.
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11. 題目: Phosphorus binding to soil organic matter via ternary complexes with calcium文章編號: N20071809
期刊: Chemosphere
作者: Yuki Audette, D. Scott Smith, Christopher T. Parsons, Weibin Chen, Fereidoun Rezanezhad, Philippe Van Cappellen
更新時間: 2020-07-18
摘要: Soil organic matter (SOM) is known to exert a major control on the mobility and bioavailability of cationic nutrients. However, the role of SOM in the fate of anionic nutrients, especially phosphorus (P), is less well characterized. The objectives of this study were to (1) compare the formation of binary complexes of calcium (Ca) with humic acids (HA) extracted from two contrasting soils, and (2) determine if binary HA-Ca complexes could incorporate P by forming ternary HA-Ca-P complexes. The Ca binding capacities of the HA extracted from an agricultural organic soil (AOS) and a pristine riparian soil (RS) were measured via potentiometric titrations; the formation of ternary complexes was analyzed by size fractionation using MWCO tubes. Proton and Ca binding capacities of RS-HA were higher than AOS-HA, and pH had a weaker effect on Ca binding to RS-HA. These differences are consistent with lower proportions of aromatic groups, and a higher proportion of alkyl groups derived from 13C NMR spectroscopy. Together, the NMR, titration and MWCO data indicate that Ca binds to RS-HA through monodentate complexes and electrostatic attraction that are capable of binding P producing ternary complexes. In contrast, at pH 8.5 Ca forms bidentate complexes with AOS-HA, which do not provide bridging positions to incorporate P. Overall, our results imply that the formation of HA-Ca and HA-Ca-P complexes depend on the structure of the HA, and that complexation to HA may play an important role in the fate of P in terrestrial and aquatic environments.
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12. 題目: Effects of organic matter components and incubation on the cement-based stabilization/solidification characteristics of lead-contaminated soil文章編號: N20071808
期刊: Chemosphere
作者: Shangqi Ge, Yize Pan, Lingwei Zheng, Xinyu Xie
更新時間: 2020-07-18
摘要: Stabilization/solidification (S/S) has been studied since 1950s and widely used for the treatment of potentially toxic elements (PTEs). The coexistence of organic matter (OM) and PTEs can cause a very complicated mechanism for cement-based S/S applications and bring challenges from both scientific and engineering perspectives. To fill in the knowledge gap, this paper investigates for the first time the effects on S/S characteristics of OM components and incubation, which are the two main factors that result in the inconsistency in the leaching characteristics from the available studies. OM samples with different components (humic acid (HA) and fulvic acid (FA)) and contents were mixed into lead-contaminated soil and incubated for different durations of up to 90 days. The experimental results show that the strength of stabilized soils increases with increasing incubation duration and the lead leaching concentration of stabilized soils is decreased by 60.7%–83.6% from zero to 90 days. The lead leaching concentration of the HA group, which is 144.0% higher with no incubation than the non-OM group, becomes 58.3% lower with 90 days of incubation. The leaching concentration of the FA group remains much higher than those of the other groups. Finally, a competing mechanism of HA—weakening cement hydration reactions and stabilizing lead with a critical incubation duration of 14 days—is proposed, together with a cooperating mechanism of FA—weakening cement hydration reactions and releasing lead.
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13. 題目: Enhanced electrochemical degradation of 2,4-dichlorophenol with the assist of hydrochar文章編號: N20071807
期刊: Chemosphere
作者: Weiming Cao, Chaju Zeng, Xiaofei Guo, Qiang Liu, Xiaolei Zhang, Naresh Mameda
更新時間: 2020-07-18
摘要: Effective treatment of 2,4-dichlorophenol (2,4-DCP) in wastewater is essential, as it could pose great threat to the environment. A hydrothermal biochar (hydrochar) was used to assist the electrochemical oxidation treatment of 2,4-DCP. The removal of 2,4-DCP using hydrochar in anode and cathode area with and without proton exchange membrane (PEM) under 3–9 V of electrolysis was investigated. Enhanced 2,4-DCP degradation in the anode area was achieved compared with the adsorption or electrolysis alone. The highest 2,4-DCP removal (∼76%) was obtained using the hydrochar in the anode area with PEM under 9 V. The mechanism for the 2,4-DCP removal during the electrolysis included adsorption by hydrochar and electrochemical degradation by the reactive oxygen species (ROS) generated by the electrode as well as the persistent free radicals (PFR) on hydrochar. The OH produced from anode was the predominant ROS contributing to the 2,4-DCP degradation under 9 V of electrolysis.
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14. 題目: Use of Brassica juncea and Dactylis glomerata for the phytostabilization of mine soils amended with compost or biochar文章編號: N20071806
期刊: Chemosphere
作者: Donato Visconti, Ma José Álvarez-Robles, Nunzio Fiorentino, Massimo Fagnano, Rafael Clemente
更新時間: 2020-07-18
摘要: Phytostabilization of mine soils contaminated by potentially toxic elements (PTEs) requires plants tolerant to PTE toxicity and to the poor soil physico-chemical characteristics of these areas. A pot experiment was carried out to assess the phytostabilization potential of Brassica juncea and Dactylis glomerata in mine soils amended with compost and biochar. Furthermore, the Environmental Risk of the soils and the effects of the phytostabilization process on the microbiological population size and activity in the soils were also determined. According to the Ecological Risk Index (ERI) the soils studied presented very high risk and As, Cd and Pb were the target elements for phytostabilization. Both amendments improved soil conditions (e.g., increasing total-N and total organic-C concentrations) and contributed to PTE (Cd, Pb and Zn) immobilization in the soil. Compost showed a more marked effect on soil microbial biomass and nutrients release in soil, which led to higher B. juncea and D. glomerata biomass in compost treated soils. Biochar treatment showed a positive effect only on D. glomerata growth, despite it provoked strong PTE immobilization in both soils. The addition of both amendments resulted in an overall reduction of PTE concentration in the plants compared to the control treatment. In addition, both plant species showed higher accumulation of PTE in the roots than in the shoots (transfer factor<1) independently of the treatment received. Therefore, they can be considered as good candidates for the phytostabilization of PTE contaminated mine soils in combination with organic amendments like biochar and compost.
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15. 題目: Effect of Natural Organic Matter on the Fate of Cadmium During Microbial Ferrihydrite Reduction文章編號: N20071805
期刊: Environmental Science & Technology
作者: Zhe Zhou, E. Marie Muehe, Elizabeth J. Tomaszewski, Juan Lezama-Pacheco, Andreas Kappler, James M. Byrne
更新時間: 2020-07-18
摘要: Natural organic matter (NOM) is known to affect the microbial reduction and transformation of ferrihydrite, but its implication toward cadmium (Cd) associated with ferrihydrite is not well-known. Here, we investigated how Cd is redistributed when ferrihydrite undergoes microbial reduction in the presence of NOM. Incubation with Geobacter sulfurreducens showed that both the rate and the extent of reduction of Cd-loaded ferrihydrite were enhanced by increasing concentrations of NOM (i.e., C/Fe ratio). Without NOM, only 3–4% of Fe(III) was reduced, but around 61% of preadsorbed Cd was released into solution due to ferrihydrite transformation to lepidocrocite. At high C/Fe ratio (1.6), more than 35% of Fe(III) was reduced, as NOM can facilitate bioreduction by working as an electron shuttle and decreased aggregate size, but only a negligible amount of Cd was released into solution, thus decreasing Cd toxicity and prolonging microbial Fe(III) reduction. No ferrihydrite transformation was observed at high C/Fe ratios using Mössbauer spectroscopy and X-ray diffraction, and X-ray absorption spectroscopy indicated the proportion of Cd-OM bond increased after microbial reduction. This study shows that the presence of NOM leads to less mobilization of Cd under reducing condition possibly by inhibiting ferrihydrite transformation and recapturing Cd through Cd-OM bond.
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16. 題目: Optical characteristics of colored dissolved organic matter during blooms of Trichodesmium in the coastal waters off Goa文章編號: N20071804
期刊: Environmental Monitoring and Assessment
作者: Siby Kurian
更新時間: 2020-07-18
摘要: Trichodesmium, a marine cyanobacterium, plays a significant role in the global nitrogen cycle due to its nitrogen fixing ability. Large patches of Trichodesmium blooms were observed in the coastal waters, off Goa during spring intermonsoon (SIM) of 2014–2018. Zeaxanthin was the dominant pigment in the bloom region. Here, we present the spectral absorption and fluorescence characteristics of colored dissolved organic matter (CDOM) during these blooms. CDOM concentration was much higher in the bloom patches as compared with nonbloom regions. During the bloom spectral CDOM absorption had distinct peaks in the UV region due to the presence of UV-absorbing/screening compounds, mycosporine-like amino acids (MAAs) and in the visible region due to phycobiliproteins (PBPs). The spectral fluorescence signatures by the traditional peak picking method exhibited three peaks, one was protein-like, and the other two were humic-like. Apart from these, Trichodesmium exhibited strong protein-like fluorescence with 370/460 nm (Ex/Em), which is a signature of cyanobacteria. A parallel factor analysis (PARAFAC) on the fluorescence excitation-emission matrix (EEM) of Trichodesmium dataset fitted a 3-component model of which one was protein-like, and two were humic-like. The fluorescence index (FI) values during Trichodesmium bloom was very high (~ 3) compared with the typical range of 1.2–1.8 observed for the natural waters. Bloom degradation experiments proved that increase in tryptophan fluorescence enhances the CDOM absorption. Our study indicates that Trichodesmium blooms provide a rich source of organic matter in the coastal waters and long-term monitoring of these blooms is essential for understanding the health of ecosystem.
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17. 題目: Saturated permeability behavior of biochar-amended clay文章編號: N20071803
期刊: Journal of Soils and Sediments
作者: Wen-Jing Sun, Ming-Yu Li, Wen-Jie Zhang, Yun-Zhi Tan
更新時間: 2020-07-18
摘要: Purpose Biochar has the characteristics of loose porosity, high specific surface area, and strong adsorption properties. Recently, the compacted biochar amended clay has been proposed as a sustainable alternative material for the final cover of landfills. However, the effect of biochar on saturated hydraulic conductivity (ksat) is not yet conclusive. The objective of this study was to determine the influence of biochar content on the permeability of biochar-clay mixed soils. Materials and methods The clay used in the study belongs to the low liquid limit clay. The biochar is produced by heating the rice straw under an oxygen-deficient condition at a temperature of 500 °C. To study the effect of biochar content on the permeability of biochar-clay mixed soils, the biochar-clay mixed soils with the mass percentage of biochar being 0%, 5%, 10%, 15%, and 20% were used. The saturated hydraulic conductivity of the biochar-clay mixed soils was measured by the head pressure control permeameter. Meanwhile, the micro-pore structure of the saturated biochar-clay mixed soils was obtained by the nuclear magnetic resonance (NMR) technique. Results and discussion It can be observed that the saturated hydraulic conductivity ksat of biochar-clay mixed soils increases linearly as the biochar content increases. The NMR results show that the T2 distribution curve of pure clay is a unimodal pattern, while the T2 distribution curve of biochar-clay mixed soils presents the bimodal pattern, where T2 is the transverse relaxation time, reflecting the pore size of the soil specimens. With the increase of biochar content, the T2 spectrum of the mixed soils moves slightly to the right, and T2 at main peak increases gradually, correspondingly the most probable pore size of biochar-clay mixed soils increases. Conclusions The pore size distribution of the soil was changed by the addition of biochar and subsequently affects the permeability of biochar-clay mixed soils. This study provides some useful suggestions for optimizing the pore structure of the biochar amended clay anti-seepage layer in the final cover of landfills. Introduction
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18. 題目: Characteristics and significance of dissolved organic matter in river sediments of extremely water-deficient basins: a Beiyun River case study文章編號: N20071802
期刊: Journal of Cleaner Production
作者: Li Zhang, Han Liu, Yongzhen Peng, Yanan Zhang, Qingxuan Sun
更新時間: 2020-07-18
摘要: The characteristics of dissolved organic matter in river sediments, affected by microorganisms, are of great significance to water management strategies. Based on three-dimensional excitation and emission matrix fluorescence, ultraviolet-visible spectroscopy, and high-throughput sequencing technology, this study jointly analyzed the composition and transformation mechanisms of dissolved organic matter as well as the microbial community structure in sediments of the Beiyun River, the main river within a basin with extreme water shortages. Moreover, we evaluated N and P contents in sediments to identify parameters to reflect potential eutrophication risks. Our results demonstrated that the content of dissolved organic matter in sediments was between 30.2 and 49.9 g/kg in the Tongzhou area of the Beiyun River. Humic substances were the largest components of dissolved organic matter in the sediments, followed by protein-like substances and soluble microbial byproducts. Furthermore, the proportion of humic matter decreased from upstream to downstream. The proportion of carbonyl, carboxyl, hydroxyl, and ester substituents on the aromatic structures of dissolved organic matter was significantly higher in the upstream, whereas the proportion of substances with aliphatic chain substituents on their aromatic structures was relatively low. The variation in downstream sediment microbial communities was much greater than that in the upstream (analyzed at the phylum level). Proteobacteria was the most abundant phylum (47.97%), which was closely related to the aromaticity of the dissolved organic matter in sediments. The N and P contents in the sediments of the Beiyun River were high and exhibited active transformation. The maximum fluorescence intensity of fulvic-acid-like components in the sediments [Fmax(C4)] can indirectly reflect the potential risk of eutrophication in the Beiyun River. Therefore, our results provide a theoretical basis for the assessment of water quality and pollution control in the Beiyun River and other water-deficient regions worldwide.
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19. 題目: Catalytic co-pyrolysis of sewage sludge and rice husk over biochar catalyst: Bio-oil upgrading and catalytic mechanism文章編號: N20071801
期刊: Waste Management
作者: Zhenzi Qiu, Yunbo Zhai, Shanhong Li, Xiangmin Liu, Xiaoping Liu, Bei Wang, Yali Liu, Caiting Li, Yanjun Hu
更新時間: 2020-07-18
摘要: In this study, the effects of different biochar catalysts on the quality of bio-oil derived from the co-pyrolysis of sewage sludge (SS) and rice husk (RH) are explored. Catalysts include SS biochar (SWC), RH biochar (RHC), mixed SS and RH biochar (SRC), and RH ash (RHA). The quality of bio-oil was evaluated based on the results of gas chromatography-mass spectrometry (GC–MS; including the contents of hydrocarbons and N-species), oxygen content, higher heating value, and pH. The GC–MS analysis results illustrated that N-species content in the bio-oil reduced with the addition of the biochar catalyst, while the hydrocarbons content increased from 15.51% for co-pyrolysis to 38.74–61.84% for different biochar catalysts at a catalytic temperature of 650 °C. RHC exhibited the best catalytic effect in terms of decreasing the content of N-species by 58.79% and increasing the content of hydrocarbons by nearly four times compared to co-pyrolysis. The higher heating value of bio-oil raised from 25.75 to 34.67 MJ/kg, while oxygen content decreased from 31.1 to 8.81 wt%, and the pH increased from 4.06 to 5.48. Moreover, the catalytic mechanism of catalytic co-pyrolysis over RHC, including the hydrocarbon generation pathway and nitrogen removal, is also discussed here. High specific surface area of RHC provides sufficient active sites (e.g. O-containing and N-containing functional groups) for the catalytic reaction of pyrolytic intermediates.
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