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本次文獻簡報涉及DOM對材料吸附鄰苯二甲酸酯類物質吸附影響[1]，消毒副產物前驅體NOM的作用[2]，寒溫帶海草草甸沉積物有機質的季節變化[3]，有機質在土壤吸附Cr(VI)預測中的作用[4]，城市清潔湖泊與非清潔湖泊CDOM吸光特徵[5]，海洋有機質呼吸化學計量學穩定性[6]，凍土來源有機質的埋藏和來源[7]，富冰凍土有機質特徵[8]，土壤有機質對高級氧化去除石油汙染物影響[9]，氣候梯度對土壤不穩定有機質組分影響[10]，含氮生物炭去除水中重金屬[11]，生物炭對雞糞堆肥過程中溫室氣體排放影響[12]，生物炭影響納米銀的生物毒性[13]，生物炭固定好氧土壤中砷鎘共汙染[14]，腐殖酸改性蒙脫土對鎘、汞的綠色修復[15]，生物標誌物對西地中海深水變化指示[16]，電場輔助膜生物反應器中胞外聚合物的減少[17]。
1. 題目: Dibutyl phthalate adsorption characteristics using three common substrates in aqueous solutions文章編號: N20010417
期刊: Frontiers of Environmental Science & Engineering
作者: Tiancui Li, Yaocheng Fan, Deshou Cun, Yanran Dai, Wei Liang
更新時間: 2020-01-04
摘要: In recent years, the presence and adverse impacts of phthalic acid esters in aquatic environments have gained increasing attention. This work investigated the adsorption behavior of a typical phthalic acid ester, dibutyl phthalate (DBP), onto steel slag, gravel, and shell sand (substrates commonly used in constructed wetlands). The influence of dissolved organic matter (DOM) on DBP adsorption was investigated using humic acid as a proxy for DOM. The results demonstrated that the adsorption of DBP to three substrates reached equilibrium within 96 h, and the adsorption kinetics were well fitted by a pseudo-second-order model. The DBP adsorption isotherms were best fitted by the Langmuir adsorption model. The DBP adsorption capacity decreased in the order of steel slag>gravel>shell sand, with values of 656 mg/kg, 598 mg/kg, and 6.62 mg/kg at 25°C, respectively. DBP adsorbed to the surface of all substrates in a monolayer via an endothermic process. The DBP adsorption capacities of steel slag and gravel decreased as the DOM content increased. The DBP adsorption mechanisms to steel slag and gravel mainly involved the surface coordination of DBP with −OH or −COOH groups and electrostatic interactions. The results of this work suggest that steel slag and gravel may be ideal substrates for use in constructed wetlands to treat wastewater polluted with DBP.
文章二維碼:2. 題目: Identification of important precursors and theoretical toxicity evaluation of byproducts driving cytotoxicity and genotoxicity in chlorination文章編號: N20010416
期刊: Frontiers of Environmental Science & Engineering
作者: Qian-Yuan Wu, Yi-Jun Yan, Yao Lu, Ye Du, Zi-Fan Liang, Hong-Ying Hu
更新時間: 2020-01-04
摘要: Chlorination, the most widely used disinfection process for water treatment, is unfortunately always accompanied with the formation of hazardous disinfection byproducts (DBPs). Various organic matter species, like natural organic matter (NOM) and amino acids, can serve as precursors of DBPs during chlorination but it is not clear what types of organic matter have higher potential risks. Although regulation of DBPs such as trihalomethanes has received much attention, further investigation of the DBPs driving toxicity is required. This study aimed to identify the important precursors of chlorination by measuring DBP formation from NOM and amino acids, and to determine the main DBPs driving toxicity using a theoretical toxicity evaluation of contributions to the cytotoxicity index (CTI) and genotoxicity index (GTI). The results showed that NOM mainly formed carbonaceous DBPs (C-DBPs), such as trichloromethane, while amino acids mainly formed nitrogenous DBPs (N-DBPs), such as dichloroacetonitrile (DCAN). Among the DBPs, DCAN had the largest contribution to the toxicity index and might be the main driver of toxicity. Among the precursors, aspartic acid and asparagine gave the highest DCAN concentration (200 g/L) and the highest CTI and GTI. Therefore, aspartic acid and asparagine are important precursors for toxicity and their concentrations should be reduced as much as possible before chlorination to minimize the formation of DBPs. During chlorination of NOM, tryptophan, and asparagine solutions with different chlorine doses and reaction times, changes in the CTI and GTI were consistent with changes in the DCAN concentration.
文章二維碼:3. 題目: High seasonal variability in sediment carbon stocks of cold‐temperate seagrass meadows文章編號: N20010415
期刊: Journal of Geophysical Research: Biogeosciences
作者: Martin Dahl, Maria E. Asplund, Diana Deyanova, João N. Franco, Alan Koliji, Eduardo Infantes, Diana Perry, Mats Björk, Martin Gullström
更新時間: 2020-01-04
摘要: Seagrass meadows have a high ability to capture and store atmospheric CO2 in the plant biomass and underlying sediment, and thereby function as efficient carbon sinks. The seagrass Zostera marina is a common species in the temperate Northern Hemisphere, a region with strong seasonal variations in climate. How seasonality affects carbon storage capacity in seagrass meadows is largely unknown, and therefore, in this study, we aimed to assess variations in sedimentary total organic carbon (TOC) content over a one‐year cycle in seagrass meadows on the Swedish west coast. The TOC was measured in two Z. marina sites, one wave exposed and one sheltered, and at two depths (1.5 and 4 m) within each site, every second month from August 2015 to June 2016. We found a strong seasonal variation in carbon density, with a peak in early summer (June), and that the TOC was negatively correlated to the net community production (NCP) of the meadows, presumably related to organic matter degradation. There was seasonal variation in TOC content at all sediment sections, indicating that the carbon content down to 30 cm is unstable on a seasonal scale and therefore likely not a long‐term carbon sink. The yearly mean carbon stocks were substantially higher in the sheltered meadow (3965 and 3465 g m‐2) compared to the exposed one (2712 and 1054 g m‐2) with similar seasonal variation. Due to the large intra‐annual variability in TOC content, seasonal variation should be considered in carbon stock assessments and management for cold‐temperate seagrass meadows.
文章二維碼:4. 題目: Predicting Cr(VI) adsorption on soils: the role of the competition of soil organic matter文章編號: N20010414
期刊: Environmental Science: Processes Impacts
作者: ZhenqingShi, ShimengPeng, XiaofengLin, YuzhenLiang, Suen-ZoneLee, Herbert E.Allen
更新時間: 2020-01-04
圖文摘要:
摘要: Cr(VI) has posed a serious risk for the environment and human beings because of its pollution and toxicity. It is essential to understand the equilibrium behavior of Cr(VI) in soils. In this study, the adsorption of Cr(VI) on fourteen soils was studied with batch experiments and quantitative modeling. The batch experiments included the adsorption edge and adsorption isotherm experiments, investigating the adsorption of Cr(VI) with varying soil properties, solution pH, and initial Cr(VI) concentrations. The experimental data were then modeled using the surface complexation models in Visual MINTEQ of CD-MUSIC by considering the adsorption of Cr(VI) and ions onto Fe (hydr)oxides and Al (hydr)oxides, and the Stockholm Humic Model and the fixed charge site model by accounting for the adsorption of the cations to soil organic matter and clay, respectively. Particularly, the modeling method of this study introduced an important parameter RO− to account for the amount of soil organic matter irreversibly adsorbed on soil minerals. Overall, the model predicted reasonably well for the equilibrium partition of Cr(VI) under various conditions with a root-mean-square-error of 0.35 for the adsorption edge data and 0.19 for the adsorption isotherm data. According to the model calculations, ferrihydrite dominated the binding of Cr(VI) at pH of 3.0–7.0. The content of ferrihydrite and reactive soil organic matter was found to be the main factor influencing RO−. The modeling results help to understand and predict Cr(VI) adsorption on different soils and are beneficial to environmental risk assessment and pollution remediation.
文章二維碼:5. 題目: Absorption characteristics of CDOM in treated and non-treated urban lakes in Changchun, China文章編號: N20010413
期刊: Environmental Research
作者: Lili Lyu, Zhidan Wen, Pierre-Andre Jacinthe, Yingxin Shang, Ning Zhang, Ge Liu, Chong Fang, Junbin Hou, Kaishan Song
更新時間: 2020-01-04
摘要: In urban settings, one may find (i) lakes that are non-treated (NT) and impacted by recurrent discharges of pollutants and nutrients, and (ii) lakes that, through restoration measures and active management, are treated (T) from external inputs. The optical properties of chromophoric dissolved organic matter (CDOM) have been used to assess the anthropogenic impact on lakes ecology, but their application in comparative assessments of urban lakes has not been attempted. For 2 years, we measured nutrients and CDOM properties in water samples collected from NT and T lakes in the city of Changchun, China. Significant differences in CDOM properties were found between the two types of lakes, and these results were supported by redundancy analysis. The NT lakes were eutrophic while the T lakes were mesotrophic, with mean trophic status index (TSI) of 74.2 and 50.3, respectively. The CDOM absorption coefficient at 350 nm, a(350), was 2-fold higher in NT than in T lakes (6.59 vs 3.21 m-1). In the NT lakes, CDOM components predominantly comprised large molecular weight (MW > 1000-Da) humus-like substances of allochthonous origin, whereas in the T lakes CDOM was dominated by low MW (<1000-Da) substances from autochthonous production. Seasonal fluctuation has a great influence on the CDOM concentration, but a little influence on its molecular composition. The CDOM concentration were higher in summer than in other seasons. Weather conditions (rainfall, temperature) and biophysical processes (biodegradation, photo-bleaching) likely contributed to these variations. We found the water quality of the treated lakes was getting better from 2016 to 2018. In summary, the study results, not only revealed seasonal effects, but most importantly documented the impact of human activities on the characteristics of CDOM in urban lakes. Most specifically, the sharp difference between the lakes in regard to a(350) (2-fold lower in T than in NT lakes) demonstrated the suitability CDOM absorption coefficient as an early indicator of the impact of treatment measures on the hydrochemistry of DOM in urban lakes.
文章二維碼:6. 題目: Stability of Marine Organic Matter Respiration Stoichiometry文章編號: N20010412
期刊: Geophysical Research Letters
作者: T. Tanioka, K. Matsumoto
更新時間: 2020-01-04
摘要: The magnitude of biological consumption of oxygen during organic matter remineralization critically depends on how much organic carbon is remineralized per unit dissolved oxygen consumed (respiratory quotient, RQ) but the global distribution and the mechanisms that control RQ are not well understood. Here, we estimate RQ in the surface ocean by using two independent methods, one using satellite‐derived macromolecular composition of phytoplankton and another using objectively gridded nutrient data. Both methods yield mean RQ of ~0.7 with small spatial variability consistent with previous estimates. This pattern is likely to be a result of phytoplankton protein content universally exceeding those of carbohydrates and lipids. At face value, the relative stability of RQ suggests that the remineralization stoichiometry will not affect the ongoing deoxygenation of the world ocean. However, the possibility that RQ may increase in the future (e.g., organic matter becoming more carbohydrate‐dominated) and thus ameliorate deoxygenation cannot be ruled out.
文章二維碼:7. 題目: Burial and origin of permafrost derived carbon in the nearshore zone of the southern Canadian Beaufort Sea文章編號: N20010411
期刊: Geophysical Research Letters
作者: H. Grotheer, V. Meyer, T. Riedel, G. Pfalz, L. Mathieu, J. Hefter, T. Gentz, H. Lantuit, G. Mollenhauer, M. Fritz
更新時間: 2020-01-04
摘要: Detailed organic geochemical and carbon isotopic (δ13C and Δ14C) analyses are performed on permafrost deposits affected by coastal erosion (Herschel Island, Canadian Beaufort Sea), and adjacent marine sediments (Herschel Basin) to understand the fate of organic carbon in Arctic nearshore environments. We use an end‐member model based on the carbon isotopic composition of bulk organic matter to identify sources of organic carbon. Monte Carlo simulations are applied to quantify the contribution of coastal permafrost erosion to the sedimentary carbon budget. The models suggest that 36 % of all carbon released by local coastal permafrost erosion is efficiently trapped and sequestered in the nearshore zone. This highlights the importance of sedimentary traps in environments such as basins, lagoons, troughs and canyons for the carbon sequestration in previously poorly investigated, nearshore areas.
文章二維碼:8. 題目: Organic Carbon Characteristics in Ice-rich Permafrost in Alas and Yedoma Deposits, Central Yakutia, Siberia文章編號: N20010410
期刊: Biogeosciences
作者: Torben Windirsch, Guido Grosse, Mathias Ulrich, Lutz Schirrmeister, Alexander N. Fedorov, Pavel Ya. Konstantinov, Matthias Fuchs, Loeka L. Jongejans, Juliane Wolter, and Jens Strauss
更新時間: 2020-01-04
摘要: Permafrost ground is one of the largest repositories of stored terrestrial natural carbon and might become a carbon source with ongoing global warming. In particular, syngenetically frozen ice-rich Yedoma deposits originating from the late Pleistocene store a large amount of carbon. This carbon has not yet become part of the recent carbon cycle. With this study of Yedoma and associated Alas deposits in Central Yakutia we aim to understand the local sediment genesis and its effect on permafrost carbon storage. For this purpose, we investigated the Yukechi Alas area (61.76495° N, 130.46664° E), a thermokarst landscape degrading into Yedoma in Central Yakutia. Two sediment cores (Yedoma upland, 22.35 m depth, and Alas basin, 19.80 m depth) were drilled in 2015. We analyzed for ice content, total carbon and total nitrogen content, total organic carbon content, stable oxygen and hydrogen isotopes, stable carbon isotopes, mass specific magnetic susceptibility, grain size distribution, and radiocarbon ages. Samples taken from both cores were radiocarbon-dated up to 50,000 years before present. The laboratory analyses of both cores revealed very low carbon contents down to several meters depth. Those core parts holding very little to no detectable carbon consist of coarser sandy material estimated to an age between 39,000 and 18,000 years before present. For this period we assume sediment input of organic-poor material. Water isotope data derived from pore ice within the Yedoma core indicate a continuously cold state of the lower core parts, thereby ruling out a potential theory of Holocene influence. In consequence, we conclude that no strong organic matter decomposition took place in the sediments of the Yedoma core until today. In contrast, the Alas core from an adjacent thermokarst basin was strongly disturbed by lake development and permafrost thaw, and accordingly its sediment and carbon characteristics differed from those of the Yedoma core. The Alas core shows homogeneous ice content and the water isotope characteristics of a slightly more decomposed organic material; the findings of very carbon-poor core sections from the Yedoma core can be duplicated. The Yedoma deposition was likely influenced by fluvial regimes in nearby streams and the Lena River shifting with climate. The low carbon content and the clear stratigraphical layering of different sediment types suggest that the Yedoma deposits in the Yukechi area differ from other Yedoma sites regarding carbon stock and sedimentological composition. We conclude that sedimentary composition and deposition regimes of Yedoma may differ significantly within the Yedoma domain. The resulting heterogeneity should be taken into account for upscaling approaches on the Yedoma carbon stock. The Alas core gives clear insights into the future development of Cenral Yakutian Yedoma deposits.
文章二維碼:9. 題目: AOPs-based remediation of petroleum hydrocarbons-contaminated soils: Efficiency, influencing factors and environmental impacts文章編號: N20010409
期刊: Chemosphere
作者: Tong Zhang, Yuanyuan Liu, Shan Zhong, Lishan Zhang
更新時間: 2020-01-04
摘要: Petroleum hydrocarbons are a class of anthropogenic compounds including alkanes, aromatic hydrocarbons, resins, asphaltenes and other organic matters, and soil pollution caused by petroleum hydrocarbons has drawn increasing interest in recent years. Multiple advanced oxidation processes (AOPs) are emerging to remediate petroleum hydrocarbons-contaminated soils, while very few studies have focused on the features of AOPs applied in soils. This review aims to provide an updated overview of the state of the science about the efficiency, influencing factors and environmental implications of AOPs. The key findings from this review include: 1) cyclodextrin and its derivatives can be used to synthesize targeting reagents; 2) soil organic matter (SOM), glucose and cement can activate persulfate; 3) SOM affects redox circumstance in soil and could be further developed for enhancing the catalysis effect of transition metals; 4) non-thermal plasma and wet oxidation are promising methods of AOPs to remove petroleum hydrocarbons from soil; 5) the occurrence, fate, and transformation of intermediates during the degradation of petroleum hydrocarbons in soil should be considered more. Overall, this review reveals an urgent need to develop the cost-effective remedial strategies for petroleum hydrocarbons contaminated soils, and to advance our knowledge on the generation, transport and propagation of radicals in soils.
文章二維碼:10. 題目: Spectral responses to labile organic carbon fractions as useful soil quality indicators across a climatic gradient文章編號: N20010408
期刊: Ecological Indicators
作者: Paulina B. Ramírez, Francisco J. Calderón, Steven J. Fonte, Fernando Santibáñez, Carlos A. Bonilla
更新時間: 2020-01-04
摘要: Light fraction (LF) and permanganate-oxidizable C (POXC) demonstrate high reliability as indicators for monitoring soil functioning in response to changes in soil organic carbon (SOC). However, mechanisms affecting the amount and composition of labile fractions and their relationship with SOC content at regional scales have not been thoroughly studied. The aim of this study was to examine the spectral features associated with these labile organic matter fractions in samples collected from 75 sites under different soil types, land use and climatic conditions in Chile. Topsoil was analyzed for total C and N content, aggregate stability, and texture. Additionally, the spectral properties of LF material and whole soils were analyzed using diffuse reflectance mid-infrared spectroscopy (MidIR). Our results show that LF shared a similar spectral composition but with different band intensities across climatic regimes. LF spectra were associated with O-alkyl C in cool and rainy areas, whereas a relative accumulation of aromatic structures was found in warmer areas. Whole soils spectra showed that SOC, POXC and aggregability were related to the prevalence of aliphatic and polysaccharides compounds in colder areas. While in warm arid areas, the stabilization of aliphatic compounds was found to be related to clay minerals. Furthermore, we found that POXC and SOC content were closely related and changes in POXC were affected by variations in climate conditions. The understanding of spectral features linked to labile SOC fractions on at larger geographical scale will contribute to the development of sustainable land management options for the prevention of land degradation in the context of adaptation to climate change.
文章二維碼:11. 題目: Micro-nano-engineered nitrogenous bone biochar developed with a ball-milling technique for high-efficiency removal of aquatic Cd(II), Cu(II) and Pb(II)文章編號: N20010407
期刊: Journal of Hazardous Materials
作者: Jiang Xiao, Rui Hu, Guangcai Chen
更新時間: 2020-01-04
圖文摘要:
摘要: A cost-effective and eco-friendly engineering method to improve biochar’s physicochemical and sorption performance is critical in various environmental applications. In this study, micro-nano-engineered nitrogenous biochars derived from cow bone meal pyrolyzed at different temperatures and were engineered with the assistance of a ball-milling technique. The ball-milled bone biochars were natural composites combined with plant biochars and hydroxyapatite components on the micro-nanoscale. Both the micropore area and the external specific surface area of the bone biochars were significantly improved after ball-milling. The sorption capacities for heavy metal ions were heavy metal ions were MBC-600 > MBC-450 > BC-600 > MBC-300 > BC-450 > BC-300, consistent with the variation tendency in the specific surface areas of the bone biochars. The adsorption capacities of MBC-600 for Cd(II), Cu(II) and Pb(II) were 165.77, 287.58 and 558.88 mg/g, respectively (T 298K, pH 5.0), representing increases of 93.91.%, 75.56% and 64.61% compared with the un-milled preparation. Surface complexation, cation exchange, chemical precipitation, electrostatic interaction and cation-π bonding were responsible for the removal of heavy metal ions by bone biochar materials. Taken together, the results show that micro-nano-engineered nitrogenous bone biochar prepared using ball-milling technology is a promising material for the remediation of heavy metals-bearing aquatic environments.
文章二維碼:12. 題目: Effects of microbial culture and chicken manure biochar on compost maturity and greenhouse gas emissions during chicken manure composting文章編號: N20010406
期刊: Journal of Hazardous Materials
作者: Hongyu Chen, Sanjeev Kumar Awasthi, Tao Liu, Yumin Duan, Xiuna Ren, Zengqiang Zhang, Ashok Pandey, Mukesh Kumar Awasthi
更新時間: 2020-01-04
圖文摘要:
摘要: The effects of chicken manure biochar (CMB) and chicken manure integrated microbial consortium (CMMC) as co-amendments were assessed on compost maturity and reduction of greenhouse gases and ammonia (NH3) emissions during chicken manure composting. Composting was conducted using six combinations of CMB and CMCC (0 % CMB + 0 % CMMC, 0 % CMB + 10 % CMMC, 2 % CMB + 10 % CMMC, 4 % CMB + 10 % CMMC, 6 % CMB + 10 % CMMC, 10 % CMB + 10 % CMMC added on a dry weight basis) in six polyvinyl chloride composting reactors for 42 days under an aerobic environment. Co-amendment of CMB and CMMC extended the thermophilic stage and promoted compost maturity. The release of greenhouse gases [nitrous oxide (N2O) and methane (CH4)] and NH3 from treatments co-amended by CMB and CMMC were reduced by 19.0–27.4 %, 9.3–55.9 % and 24.2–56.9 %, respectively, compared with the control. In addition, a redundancy analysis showed that the C/N ratio and temperature had a significant relationship with greenhouse gases and NH3 emissions among all physiochemical characteristics.
文章二維碼:13. 題目: Biochar-induced immobilization and transformation of silver-nanoparticles affect growth, intracellular-radicles generation and nutrients assimilation by reducing oxidative stress in maize文章編號: N20010405
期刊: Journal of Hazardous Materials
作者: Qumber Abbas, Balal Yousaf, Habib Ullah, Muhammad Ubaid Ali, Muhammad Zia-ur-Rehman, Muhammad Rizwan, Jörg Rinklebe
更新時間: 2020-01-04
圖文摘要:
摘要: Silver nanoparticles (AgNPs) are used in a wide range of consumer products inevitably releases in massive quantities in the natural environment, posing a potential thread to ecosystem-safety and plant health. Here, the impact of AgNPs (100−1000 mg L−1) without and with biochar (@2 % w/v) amendment on maize plants was assessed in hydroponics exposure medium. AgNPs exposure to plants induced dose-dependent phytotoxicity by suppressing plant growth, disturbing photosynthesis and gas exchange traits and alteration in macro- and micronutrients assimilation. At the same time, AgNPs with addition of biochar alleviated the phyto-toxic effects of AgNPs through approximately 4–8 times reduction in uptake and tissue accumulation of Ag. Moreover, activities of antioxidant enzymes in AgNPs + biochar treated plants indicated the lower oxidative stress. Electron paramagnetic resonance (EPR) spectroscopy confirmed that superoxide (O2−) radical was the dominant reactive oxygen species. Fourier-transform infrared spectroscopic (FTIR) and X-ray photoelectron spectroscopic (XPS) results revealed that biochar surface carboxyl and sulfur functional groups were involved in complexation process with NPs, which inhibited the oxidative dissolution and release of Ag+ ions besides of biochar space shield effect. Thus, the interaction of biochar with AgNPs immobilizes these NPs and can effectively reduce their bioavailability in the environmental matrix.
文章二維碼:14. 題目: A novel calcium-based magnetic biochar is effective in stabilization of arsenic and cadmium co-contamination in aerobic soils文章編號: N20010404
期刊: Journal of Hazardous Materials
作者: Jizi Wu, Zhangtao Li, Dan Huang, Xingmei Liu, Caixian Tang, Sanjai J. Parikh, Jianming Xu
更新時間: 2020-01-04
圖文摘要:
摘要: This study developed a novel calcium-based magnetic biochar by pyrolysing rice straw mixed with calcium carbonate and iron oxide for stabilization of contamination of multiple metals. A 160-day incubation study was conducted to investigate its performance in stabilization of cadmium and arsenic co-contamination in soil. Both biochar and Ca-MBC treatments increased soil pH, decreased the bioavailability of cadmium. Ca-MBC decreased but biochar enhanced the bioavailability of arsenic. The BCR (European Community Bureau of Reference) sequential extraction confirmed Ca-MBC facilitated the transformation of the unstable fraction of arsenic to stable fractions. The stabilization mechanisms were explored through synchrotron-based micro X-ray fluorescence and X-ray absorption near edge structure. The results show that Ca-MBC remediated the dual contamination of arsenic and cadmium through (1) elevated pH and cation exchange capacity (for Cd); (2) the formation of bi-dentate chelate and ternary surface complexes on the surface of iron oxide; (3) enhanced adsorption ability of porous biochar. In addition, Ca-MBC increased the abundance and diversity of bacterial community, and modified the relative abundances of bacterial taxa, leading to a shift of the composition. These new insights provide valuable information for stabilization of co-contamination of arsenic and cadmium in soil using the potential material Ca-MBC.
文章二維碼:15. 題目: Green remediation of Cd and Hg contaminated soil using humic acid modified montmorillonite: immobilization performance under accelerated ageing conditions文章編號: N20010403
期刊: Journal of Hazardous Materials
作者: Liuwei Wang, Xuanru Li, Daniel C.W. Tsang, Fei Jin, Deyi Hou
更新時間: 2020-01-04
圖文摘要:
摘要: Solidification/Stabilization (S/S) is an effective way to immobilize toxic metals in contaminated soil. However, utilization of ordinary Portland cement (PC) in this process has raised environmental concerns owing to the high carbon footprint from PC manufacturing and the risk of toxic element leaching in the long term. Hence there is an urgent need to seek for 「green」 immobilization approaches with long-term stability. In this study, a clay-based material, humic acid modified montmorillonite (HA-Mont) was applied to a Cd and Hg contaminated soil. Field emission scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (FESEM/EDS), N2 adsorption-desorption, Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analyses were performed to investigate the characteristics of this material. Compared to the soil without any treatment, dosage of 5% HA-Mont could effectively reduce Cd and Hg concentrations by 94.1% and 93.0%, respectively and to below the regulatory limits in the TCLP (Toxicity Characteristic Leaching Procedure) leachates. Compared to the soil treated with virgin montmorillonite, HA modification resulted in the reduction of leachate concentrations of Cd and Hg by 69.5% and 65.9%, respectively. Long-term immobilization performance of the HA-Mont treatment was examined using a quantitative accelerated ageing method. In order to examine the ageing features, a novel method based on conditional probability was developed, and the reliability of HA-Mont immobilization was found to fit the Weibull model well, as the ageing rate of immobilization effect increased with time. After 120 years of ageing, reliability of both metals could still remain above 0.95. Cd concentration in TCLP leachates at 120th year could still remain below the regulatory limit (294 μg/L vs 1000 μg/L), while Hg concentration reached the regulatory limit of 200 μg/L in 96th year. This is the first attempt developing a green S/S method of Cd and Hg contaminated soil using HA-Mont and examining the long-term ageing characteristics of the stabilized soil using a probability-based approach.
文章二維碼:16. 題目: Surface and deep water variability in the Western Mediterranean (ODP Site 975) during insolation cycle 74: High-resolution calcareous plankton and molecular biomarker signals文章編號: N20010402
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Ornella Quivelli, Maria Marino, Teresa Rodrigues, Angela Girone, Patrizia Maiorano, Fatima Abrantes, Emília Salgueiro, Frank Bassinot
更新時間: 2020-01-04
摘要: We reconstructed changes in productivity and surface/subsurface and deep-water dynamics in the Western Mediterranean through a multi-proxy study of Ocean Drilling Program Site 975 between late Marine Isotope Stage (MIS) 20 and early interglacial MIS 19. Our high-resolution study (down to ~200-year resolution) combines calcareous plankton assemblages (coccolithophores and foraminifera), biomarkers (C37-alkenones, n-alkanes, n-alcohols) and elemental proxies (total organic carbon, total nitrogen, calcium carbonate). Surface water conditions are derived (i) from high-resolution δ18O and δ13C records obtained from the planktonic foraminifer Globigerina bulloides, and (ii) from summer and winter, foraminifera-based sea surface temperature reconstructions (SSTJAS-foram, SSTJFM-foram) achieved through transfer function. The integration of the whole dataset makes it possible to identify in the Balearic Sea, and to accurately characterize for the first time, an Organic Rich Layer (ORL) during latest MIS 20-early MIS 19, close to i-cycle 74. Its presence is marked firstly by higher values of total nitrogen (TN) and an increase of total C37-alkenone and total organic carbon (TOC) preserved in the sediments. The multi-proxy approach reveals that the deglacial phase played a prominent role for ORL formation that was characterized by centennial scale phases. The alcohol preservation index (API) suggests that the shoaling of the circulation, which boosted marine productivity, started in the deglaciation and, in combination with freshening by Atlantic water inflow/riverine input and surface water buoyancy during sea level rising, culminated during the ORL event. At this time calcareous plankton proliferated on subsurface-surface waters, benefiting from ameliorating conditions, which promoted maximum marine productivity and higher organic matter preservation on the seafloor.
文章二維碼:17. 題目: The growth process of the cake layer and membrane fouling alleviation mechanism in a MBR assisted with the self-generated electric field文章編號: N20010401
期刊: Water Research
作者: Xiafei Yin, Xiufen Li, Zhaozhe Hua, Yueping Ren
更新時間: 2020-01-04
圖文摘要:
摘要: The electric field assisted membrane bioreactor (MBR) is an effective technique to alleviate membrane fouling. In this study, the spontaneous electric field was introduced into the MBR to observe the growth process of cake layer on the membrane surface. The external resistance for spontaneous electric field MBR (S-50) and S-500 were 50 Ω and 500 Ω respectively. During the experiments, S-50 maintained the highest electric field intensity of 11.83 mV/cm. The reduction of extracellular polymeric substances (EPS) content in activated sludge, transmembrane pressure (TMP) growth rate reached 52.8% and 51.7% respectively. After 28 days operation, S-50 obtained the minimum contaminant specific biovolume (23.316 μm3/μm2), which was 68.2% lower than that of it in Control-MBR. The metal oxide or metal hydroxide were distributed in the cake layer. EPS played a significant role in the formation and growth of the cake layer. Based on the results obtained in this study, the growth of the biofouling layer on the membrane surface could be divided into three stages. EPS first deposited on the membrane surface, and then microorganisms embedded in the cake layer to form clusters. After that, EPS and total cells further increased and led to a faster biovolume growth rate. Subsequently, the biovolume growth rate decreased in the cake layer. The spontaneous electric field delayed the deposition of EPS on the membrane surface. The produced H2O2 and •OH were beneficial to the degradation of organics, causing the smaller contaminant biovolume on the membrane surface. This work aims to provide a theoretical basis for the practical application of the electric field to control membrane fouling.
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