1. 题目: Temperature‐regulated turnover of chromophoric dissolved organic matter in global dark marginal basins
期刊: Geophysical Research Letters
作者: Chao Wang, Weidong Guo, Yan Li, Randy A Dahlgren, Xianghui Guo, Liyin Qu, Wei Zhuang
摘要: Oceanic absorption of heat generated by greenhouse gas emissions has resulted in warming of the dark ocean (>200 m) that contains a large refractory DOM (RDOM) pool. However, changes in microbially-mediated production and degradation dynamics for RDOM components in response to warming of dark marginal basins remain unclear. Herein, we integrated data from the dark South China, Mediterranean and Japan Seas (temperature range: 0.09 – 15.1 oC) to demonstrate that in situ production efficiency of two ubiquitous humic-like fluorophores increased at higher dark ocean temperature, whereas chromophores at a wavelength of 325 nm (aCDOM(325)) changed from production to degradation at higher temperature. Increased oxygen consumption and a reduction of labile substrates in future warmer dark ocean environments may initiate the final degradation of some semi-refractory components, thereby increasing the recalcitrance of RDOM, but decreasing the DOM inventory in dark basins and creating a positive feedback to rising atmospheric CO2.
2. 题目: Impact of the elemental composition of exported organic matter on the observed dissolved nutrient and trace element distributions in the upper layer of the ocean
期刊: Global Biogeochemical Cycles
作者: Paul Quay
摘要: Systematic regional variations in the ratio of nutrient depth gradients of dissolved inorganic carbon (ΔDIC): nitrate (ΔNO3): phosphate (ΔPO4) in the upper layer (300m) of the Pacific Ocean are observed. Regional variations in the ΔDIC/ΔNO3/ΔPO4 are primarily the result of three processes, that is, the C/N/P of organic matter (OM) being exported and subsequently degraded, nitrogen fixation and air-sea CO2 gas exchange. The link between the observed dissolved ΔDIC/ΔNO3/ΔPO4 and the C/N/P of exported OM is established using surface layer dissolved DIC, NO3 and PO4 budgets. These budgets, in turn, provide a means to indirectly estimate the C/N/P of OM being exported from the surface layer of the ocean. The indirectly estimated C/N/P of exported OM reach maxima in the subtropical gyres at 177/22/1 that is significantly greater than the Redfield ratio and a minimum in the equatorial ocean at 109/16/1 with both results agreeing with available observed particle C/N/P and ocean biogeochemical models. The budget approach was applied to a bioactive trace element (TE) using the measured dissolved Cadmium (Cd) to PO4 gradients to estimate the Cd/P of exported OM in the Pacific Ocean. Combining the budget method with the availability of high-quality dissolved nutrient and trace element data collected during the GOSHIP and GEOTRACES programs could potentially provide estimates of the C/N/P/TE of exported OM on global ocean scales which would significantly improve our understanding of the link between the ocean’s biological pump and dissolved nutrient distributions in the upper ocean.
3. 题目: Highly efficient bio-adsorption of Malachite green using Chinese Fan-Palm Biochar (Livistona chinensis)
作者: Balendu Shekher Giri, Ravi Kumar Sonwani, Sunita Varjani, Deepshi Chaurasia, Thivaharan Varadavenkatesan, Preeti Chaturvedi, Sudeep Yadav, Vimal Katiyar, Ram Sharan Singh, Ashok Pandey
摘要: The discharge of effluents from the textile industry is a multidimensional problem that affects the ecosystem in many ways. Though many new technologies are being developed, it remains to be seen which of those can be practiced in a real scenario. The current investigation attempts to absorb the Malachite Green, an effluent from textile dye using Chinese Fan Palm Seed Biochar. Accordingly, biochar was prepared using fruits of Chinese Fan Palm (Livistona chinensis) tree. The fruit also yielded a significant amount of biochar and bio-oil. 1.346 kg of fresh and cleaned fruit was fast pyrolyzed at 500 °C in a laboratory-scale Pyrolyzer resulting in 0.487 kg of biochar and 0.803 L of bio-oil. The remaining fruit matter was converted to gaseous products. The kinetics of dye removal were studied and the parameters were determined. The study advocates that the Langmuir isotherm model simulates the adsorption experiment, to a good extent. From the plot, the maximum (monolayer) adsorption capacity, Qm was determined to be 21.4 mg/g. The suitability of the Langmuir isotherm model onto biochar was established by the high correlation coefficient, R2 that was higher than 0.97.
4. 题目: Large circulation patterns strongly modulate long term variability of Arctic black carbon levels and areas of origin
期刊: Geophysical Research Letters
作者: V K Stathopoulos, N Evangeliou, A Stohl, S Vratolis, C Matsoukas, K Eleftheriadis
摘要: Black Carbon (BC) aerosol is a major climate forcer in the Arctic. Here we present 15 years (2001-2015) of surface observations of the aerosol absorption coefficient babs (corresponding to Equivalent BC), obtained at the Zeppelin Observatory, Ny Ålesund, Svalbard, coupled with backward transport modeling with FLEXPART in order to calculate the Potential Source Contribution Function (PSCF) for BC. The observed long term variability superimposed on a strong annual cycle is studied as a function of large-scale circulation patterns represented by monthly index values for the North Atlantic Oscillation (NAO) and the Scandinavian pattern (SCAN). We find a 35% increase of babs values at Zeppelin during the SCAN- phase in the winter half-year compared to the SCAN+ phase but no significant difference in babs values between the NAO index phases. Both NAO and SCAN induce significant regional variability on the areas of origin of babs, mainly Siberia, Europe & North America
5. 题目: Application of a combinatorial approach for soil organic carbon mapping in hills
期刊: Journal of Environmental Management
作者: Youlin Luo, Kai Wang, Huanxiu Li, Changquan Wang, Qiquan Li
摘要: Accurate mapping of soil organic carbon (SOC) is critical to improve C management and develop sustainable management policies. However, it is constrained by local variations of the model parameters under complex topography, especially in hills. This study applied a methodological framework to optimize the spatial prediction of SOC in the hilly areas during 1981–2012 by quantifying the relative importance of environmental factors, which include both qualitative factors and quantitative variables. Results showed that SOC increased twofold with a moderate spatial dependence during the past 32 years. During this period, land use patterns, soil groups, topographic factors, and vegetation coverage had significant impacts on the SOC changes (p < 0.01). Specifically, the impact of land use patterns has exceeded the impact of soil groups and became the dominant factor affecting SOC changes. Meanwhile, impacts from the topographic factors and vegetation coverage have substantially declined. Based on those results, a combinatorial approach (LS_RBF_HASM) was developed to map SOC using radial basis function neural network (RBF) and high accuracy surface modelling (HASM), and to generate more detailed spatial mapping relationships between SOC and the affecting factors. Compared with ordinary kriging (OK), land use-soil group units (LS) and HASM combined (LS_HASM), multiple linear regression (MLR) and HASM combined with LS (LS_MLR_HASM); LS_RBF_HASM showed a better performance with a decline of 6.3%–37.7% prediction errors and more accurate spatial patterns due to the quantitative combination of auxiliary environmental variables and more information on the SOC variations within local factors captured by RBF and HASM. Additionally, MLR may partially undermine the relationship of the internal spatial structure due to the highly nonlinear relation between SOC and environmental variables. This methodological framework highlights the optimization of more environmental factors and the calculation of spatial variability within local factors and provides a more accurate approach for SOC mapping in hills.
6. 题目: An 1800-year record of lake level and climate change from alkaline lakes in southern Inner Mongolia, China
期刊: Journal of Paleolimnology
作者: Fei Tian, Yong Wang, Jin Dong, Lupeng Yuan, Wenkun Tang
摘要: Paleoclimatic records from the East Asian summer monsoon (EASM) margin are regarded as a direct reflection of the intensity and northern extent of the EASM. Here, we focus on reconstructing climatic evolution over the past 1800 years from two alkaline lakes, Chagan Nuur and Sangin Dalai Nuur, in southern Inner Mongolia. With age control provided by 13 Accelerator Mass Spectrometry radiocarbon ages and 210Pb/137Cs dating, analyses of grain size, X-ray diffraction, magnetic susceptibility, carbonate content, total nitrogen, total organic carbon and the stable isotopic composition of carbon (δ13C) and nitrogen (δ15N) in sedimentary organic matter and calculation of organic carbon to nitrogen atomic ratios have been performed to investigate hydrodynamic processes, ecological conditions and corresponding lake-level fluctuations, in response to climate change. Our results show that the lake level of Changan Nuur frequently fluctuated since 546 CE, with four centennial-scale intervals of lake expansion at around 755, 1178, 1350 CE, and after 1950 CE, and one interval of lake recession from 1593 to 1782 CE. Sangin Dalai Nuur experienced mainly low-amplitude lake-level fluctuations since 212 CE, except for severe lake shrinkage from 1417 to 1872 CE. A regional comparison shows that three warm and humid intervals (640–800 CE, 1088–1288 CE, and after 1950 CE) and one cold and dry interval (1417–1872 CE) recognized from our records could correspond to the Sui-Tang Warm Period, the Medieval Climate Anomaly, the Current Warm Period and the Little Ice Age, respectively. Moreover, our results are roughly synchronous with moisture conditions revealed by proxy records from monsoonal northern China, demonstrating that the highly variable lake levels and climatic conditions in southern Inner Mongolia were controlled by centennial-scale variations in EASM over the past 1800 years.
7. 题目: Accumulation of phthalates under high versus low nitrogen addition in a soil-plant system with sludge organic fertilizers instead of chemical fertilizers
期刊: Environmental Pollution
作者: Kunlong Hui, Jun Tang, Yini Cui, Beidou Xi, Wenbing Tan
摘要: Nitrogen is the main nutrient in soil. The long-term addition of N leads to changes in the soil dissolved organic matter (DOM) and other quality indicators, which affects the adsorption and accumulation of organic pollutants. The use of organic fertilizer is important for the development of green agriculture. However, organic fertilizers (especially sludge organic fertilizers (SOFs) contain phthalates (PAEs) that may accumulate in the soil and result in environmental contamination. How this accumulation response varies with the magnitude of long-term N addition, especially in different soil layer profiles, remains unclear. Here, changes in the content of PAEs in the soil–plant system without and after SOFs application were studied through field experiments in soils with different N addition backgrounds (CK, N1, N3 (0, 100, 300 kg N ha−1 yr−1 respectively)). Our results showed that the application of SOFs increase the accumulation of PAEs in soil profiles and plant systems, increasing human health risks. The content of Σ5PAEs in the topsoil increased from 0.96 ± 0.10 to 1.86 ± 0.09 mg kg−1. Moreover, under a high N addition background and SOFs application, the characteristics of soil DOM change, and the accumulation of PAEs in soil was nearly 30% higher compared with the low N group. Some suggestions such as removing PAEs from SOFs during preparation, conducting soil surveys before applying PAEs, and using soil amendments, which are provided for optimizing the trialability and environmental safety of SOFs application.
8. 题目: Vermiculite and humic acid improve the quality of green waste compost as a growth medium for Centaurea cyanus L.
期刊: Environmental Technology & Innovation
作者: Xueqing Feng, Lu Zhang
摘要: Green waste compost (GWC) is a value-added product generated by the composting of urban green waste. Although GWC could potentially be used as a growth medium for soilless culture of plants, GWC alone has high salinity, high pH, and other undesirable physicochemical properties. In the current study, we therefore assessed how addition of vermiculite (VMT: 0, 3.5, and 7%) and humic acid (HA: 0, 0.5, and 1 g/100 g) affected the physicochemical properties of GWC and its use as a growth medium for cornflower (Centaurea cyanus L.). GWC modified by the combination of 3.5% VMT and 0.5 g/100 g HA had the best physicochemical properties (bulk density, porosity, water holding capacity, electrical conductivity, pH, and nutrient content) and resulted in the best growth of cornflower in terms of plant height, maximum root length, flower number, and biomass. The results therefore indicate that GWC modified by 3.5% VMT and 0.5 g/100 g HA powder is an excellent soilless growth medium.
9. 题目: Seasonal Contribution of Isoprene-Derived Organosulfates to Total Water-Soluble Fine Particulate Organic Sulfur in the United States
期刊: ACS Earth and Space Chemistry
作者: Yuzhi Chen, Tracy Dombek, Jenny Hand, Zhenfa Zhang, Avram Gold, Andrew P. Ault, Keith E. Levine, Jason D. Surratt
摘要: Organosulfates (OSs) are the most abundant class of organosulfur (OrgS) compounds in atmospheric fine particulate matter (PM2.5). Globally, isoprene-derived OSs (iOSs) are the most abundantly reported OSs; however, total sulfur mass closure in PM2.5 has not been conducted at the molecular level in order to understand how iOS contributions vary by season and by location in the United States (U.S.). In this work, iOSs were quantitively characterized in PM2.5 collected from 20 ground sites within the Interagency Monitoring of Protected Visual Environments (IMPROVE) network during the 2016 summer and winter seasons. Total water-soluble sulfur (TWS-S) and sulfur from inorganic sulfate (Sinorg) were also chemically determined, with the imbalance between TWS-S and Sinorg used as an upper-bound estimate of water-soluble OrgS concentrations. Significantly higher fine particulate OrgS concentrations (∼20% of TWS-S) were observed at most sites only in summer, coincident with elevated iOS concentrations in the eastern U.S. On average, iOSs (130 ng m–3) explained 29 and 4% by mass of OrgS and of organic matter (OM), respectively, in the eastern U.S. In the western U.S., iOSs (11 ng m–3, on average) accounted for 6 and 0.5% by mass of OrgS and OM, respectively. In winter, iOSs were hardly detected, consistent with reduced isoprene emissions. Our study shows that ∼70 and 80% of OrgS mass in the eastern U.S. and western U.S., respectively, remain unexplained at the molecular level. This study provides critical insights into the abundance, prevalence, and spatial variability of fine particulate iOSs across the U.S.
10. 题目: pH-dependent contribution of chlorine monoxide radicals and byproducts formation during UV/chlorine treatment on clothianidin
期刊: Chemical Engineering Journal
作者: Youn-Jun Lee, Chang-Gu Lee, Seong-Jik Park, Joon-Kwan Moon, Pedro J.J. Alvarez
摘要: Combining UV and free chlorine (UV/chlorine) is an efficient advanced oxidation process for the abatement of recalcitrant organic compounds in drinking water and wastewater. This study investigated the degradation of a neonicotinoid insecticide, clothianidin (CTD), by UV/chlorine treatment. The free chlorine concentration was optimized at 160 μM, and 90.1 ± 0.4% of 40 μM CTD was degraded after 300 s of treatment. Radical quenching tests using tert-butyl alcohol, Cl-, HCO3-, and N3- indicated that chlorine monoxide (ClO•) was the main radical species for CTD degradation. The second-order rate constants of CTD reacting with ClO• kclo•,CTD = 7.3 ± 0.1 × 109 M-1s-1) was 4.3 times higher than that for •OH kclo•,CTD = 1.7 ± 0.2 × 109 M-1s-1). The presence of humic acid inhibited CTD degradation by filtering UV and scavenging ClO•. The pH was optimized at 7, and the overall reaction rate constant (k′) was 2.35 ± 0.02 × 10-2 s-1 (half-life = 0.49 min). Degradation products identified during the UV/chlorine treatment were 1-methyl-3-nitroguanidine ([M+H]+ = 118.9), nitroguanidine ([M+H]+ = 105.1), methylguanidine ([M+H]+ = 74.3), and clothianidin urea ([M+H]+ = 206). The detailed time-dependent concentrations of the generated products under different pH conditions were also provided. The results suggest that the UV/chlorine treatment can be an efficient strategy for CTD degradation.
11. 题目: Contrasting estuarine processing of dissolved organic matter derived from natural and human‐impacted landscapes
期刊: Global Biogeochemical Cycles
作者: E. Elena García‐Martín, Richard Sanders, Chris D. Evans, Vassilis Kitidis, Dan J. Lapworth, Andrew P. Rees, Bryan Spears, Andy Tye, Jennifer L. Williamson, Chris Balfour, Mike Best, Michael Bowes, Sarah Breimann, Ian J. Brown, Annette Burden, Nathan Callaghan, Stacey L. Felgate, James Fishwick, Mike Fraser, Stuart Gibb, Pete J. Gilbert, Nina Godsell, Africa P. Gomez‐Castillo, Geoff Hargreaves, Oban Jones, Paul Kennedy, Anna Lichtschlag, Adrian Martin, Rebecca May, Edward Mawji, Ian Mounteney, Philip D. Nightingale, Justyna P. Olszewska, Stuart C. Painter, Christopher R. Pearce, M. Glória Pereira, Kate Peel, Amy Pickard, John A. Stephens, Mark Stinchcombe, Peter Williams, E. Malcolm S. Woodward, Deborah Yarrow, Daniel J. Mayor
摘要: The flux of terrigenous organic carbon through estuaries is an important and changing, yet poorly understood, component of the global carbon cycle. Using dissolved organic carbon (DOC) and fluorescence data from thirteen British estuaries draining catchments with highly variable land uses, we show that land use strongly influences the fate of DOC across the land-ocean transition via its influence on the composition and lability of the constituent dissolved organic matter (DOM). In estuaries draining peatland-dominated catchments, DOC was highly correlated with biologically refractory “humic-like” terrigenous material which tended to be conservatively transported along the salinity gradient. In contrast, there was a weaker correlation between DOC and DOM components within estuaries draining catchments with a high degree of human impact, i.e. relatively larger percentage of arable and (sub-)urban land uses. These arable and (sub-)urban estuaries contain a high fraction of bioavailable “protein-like” material that behaved non-conservatively, with both DOC removals and additions occurring. In general, estuaries draining catchments with a high percentage of peatland (≥18 %) have higher area-specific estuarine exports of DOC (>13 g C m-2 yr-1) compared to those estuaries draining catchments with a high percentage (≥46 %) of arable and (sub-)urban land uses (<2.1 g C m-2 yr-1). Our data indicate that these arable and (sub-)urban estuaries tend to export, on average, ∼50 % more DOC to coastal areas than they receive from rivers, due to net anthropogenic derived organic matter inputs within the estuary.
12. 题目: Iron-Modified Biochar from Sugarcane Straw to Remove Arsenic and Lead from Contaminated Water
期刊: Water, Air, & Soil Pollution
作者: Matheus Bortolanza Soares, Felipe Hipólito dos Santos, Luís Reynaldo Ferracciú Alleoni
摘要: The presence of arsenic (As) and lead (Pb) in water above tolerable levels is a global concern, as both elements are extremely toxic and can compromise the health of millions of people. In this study, we evaluated biochars pyrolyzed at 350 (BC350) and 750 °C (BC750) and then modified with ferric chloride (FeCl3) to remove As and Pb from water samples contaminated by mining activity. The use of FeCl3-modified biochar was an efficient strategy to remove As and Pb from water. Sorption on biochars followed the pseudo-second-order kinetics, represented by two sorption speeds, being higher at the beginning of the reaction and falling over time. The modification with FeCl3 increased the specific surface area, removed the dissolved organic carbon, and increased the capacity of BC350 to sorb Pb. These physical and chemical alterations of the biochar played a significant role in the sorption capacity and speed of As and Pb.
13. 题目: The environmental effect on the seabed of an offshore marine fish farm in the tropical Pacific
期刊: Journal of Environmental Management
作者: Carlos Sanz-Lazaro, Nuria Casado-Coy, Edwin Moncayo Calderero, Ulises Avendaño Villamar
摘要: Marine aquaculture is expanding offshore, where the environmental interactions are not yet fully understood. We performed a benthic environmental assessment of an offshore fish farm on unconsolidated sediment. The physicochemical variables showed marked changes just under the fish farm, although the structure of the community and its bioturbation potential were not influenced. Under no or minimum influence from the fish farm, the physicochemical variables, including acid-volatile sulphides and redox, were notably different to those found in unaffected coastal areas. For this reason, classifications of the environmental status based on physicochemical variables should be adapted to offshore areas. Despite the low degree of impact detected, the organic matter carrying capacity should be carefully determined to avoid environmental drawbacks in terms of fine-grained offshore sediments. Offshore aquaculture could have a lower environmental impact than other types of aquaculture located closer to the coast, but further research is needed to obtain conclusive results.
14. 题目: Climate-Associated Changes in Mercury Sources in the Arctic Fjord Sediments
期刊: ACS Earth and Space Chemistry
作者: Ju Hyeon Lee, Sae Yun Kwon, Hoin Lee, Seung-Il Nam, Jung-Hyun Kim, Young Ji Joo, Kwangchul Jang, Haryun Kim, Runsheng Yin
摘要: Despite the large climatic fluctuations in the Arctic over the Holocene, the dominant mercury (Hg) sources and the potential changes in Hg sources associated with the climate remain unclear. Here, we use Hg isotopes to reconstruct changes in Hg sources and processes in two Svalbard fjord sediment cores spanning the Holocene. The Hg isotope ratios of the fjord sediment cores are similar to bedrock and Hg bound to terrestrial total organic carbon (TOC) but different from other sediment cores influenced by atmospheric Hg drawdowns via the sinking of marine particulate organic matter. The absence of significant Hg and TOC relationships indicates that bedrock erosion caused by glacier dynamics is the major Hg source to the fjord sediment rather than those bound to marine and terrestrial TOC. Measurable shifts in Hg sources are observed at regional cooling (4.3 ka) and during the Medieval Warm Period in the late Holocene. The negative shift in δ202Hg (by −0.5‰) at 4.3 ka from baseline (∼10 ka) is consistent with the rapid increase in glacier-mediated physical and chemical erosions of bedrock. The significant positive shifts in δ202Hg (by 0.5‰) in the late Holocene are explained by enhanced input of atmospheric Hg and its drawdown via the sinking of marine particulate organic matter and some anthropogenic influence, which suppressed the positive Δ199Hg and Δ200Hg shifts. This study suggests that Hg isotope ratios measured in sedimentary archives can be used to decipher climate and other local to global changes modifying Hg sources in the Arctic.
15. 题目: A review of pesticides sorption in biochar from maize, rice, and wheat residues: Current status and challenges for soil application
期刊: Journal of Environmental Management
作者: Allan Pretti Ogura, Jacqueline Zanin Lima, Jéssica Pelinsom Marques, Lucas Massaro Sousa, Valéria Guimarães Silvestre Rodrigues, Evaldo Luiz Gaeta Espíndola
摘要: The use of pesticides has been increasing in recent years for maintaining traditional agricultural practices. However, these chemicals are associated with several environmental impacts, demanding urgent remediation techniques. Biochar is a carbonaceous material produced by pyrolysis that has the potential for pesticide sorption and remediation. In this context, this interdisciplinary review systematically assessed the state of the knowledge of crop residues to produce biochar for pesticide sorption. We focused on maize, rice, and wheat residues since these are the three most-produced grains worldwide. Besides, we evaluated different biochar handling, storage, and soil dispersion techniques to ease its implementation in agriculture. In general, pyrolysis temperature influences biochar characteristics and its potential for pesticide sorption. Furthermore, biochar amended soils had greater pesticide sorption capacity, limiting potential leaching and runoff. Most studies showed that the feedstock and specific surface area influence the biochar sorption properties, among other factors. Also, biochar reduces pesticides’ bioavailability, decreasing their toxicity to soil organisms and improving soil fertility and crop yields. Nonetheless, the retrieved papers assessed only 21 pesticides, mainly consisting of lab-scale batch experiments. Therefore, there is still a gap in studies evaluating biochar aging, its potential desorption, pesticide co-contaminations, the associated microbiological processes, and field applications. Determining flow properties for biochars of different sizes and pellets is vital for reliable handling equipment design, and performing techno-economic assessment under different farm contexts is encouraged. Ultimately, coupling biochar production with residue management could address this challenge on sustainable agricultural systems.
16. 题目: Evaluation of oil palm fiber biochar and activated biochar for sulphur dioxide adsorption
期刊: Science of The Total Environment
作者: Nursashabila Iberahim, Sumathi Sethupathi, Mohammed J.K. Bashir, Ramesh Kanthasamy, Tanveer Ahmad
摘要: The emission of sulphur dioxide (SO2) gas from power plants and factories to the atmosphere has been an environmental challenge globally. Thus, there is a great interest to control the SO2 gas emission economically and effectively. This study aims to use and convert abundantly available oil palm fiber (OPF) biomass into an adsorbent to adsorb SO2 gas. The preparation of OPF biochar and activated biochar was optimised using the Response Surface Methodology (RSM) based on selected parameters (i.e., pyrolysis temperature, heating rate, holding time, activation temperature, activation time and CO2 flowrate). The best adsorbent was found to be the OPF activated biochar (OPFAB) compared to OPF biochar. OPFAB prepared at 753 °C for 73 min of activation time with 497 ml/min of CO2 flow yields the best adsorption capacity (33.09 mg/g) of SO2. Meanwhile, OPF pyrolysed at 450 °C of heating temperature, 12 °C/min of heating rate and 98 min of holding time yield adsorption capacity at 18.62 mg/g. Various characterisations were performed to investigate the properties and mechanism of the SO2 adsorption process. Thermal regeneration shows the possibilities for the spent adsorbent to be recycled. The findings imply OPFAB as a promising adsorbent for SO2 adsorption.
17. 题目: Responses of Arbuscular Mycorrhizal Fungi Occurrence to Organic Fertilizer: A meta-analysis of field studies
期刊: Plant and Soil
作者: Shangtao Jiang, Xiangrui An, Yadong Shao, Yalong Kang, Tingsu Chen, Xinlan Mei, Caixia Dong, Yangchun Xu, Qirong Shen
摘要: Background and aims It has been confirmed that the declines in arbuscular mycorrhizal fungi (AMF) populations and agroecosystem diversity are largely due to nutrient enrichment caused by fertilization. Replacing chemical-only fertilization with organic fertilization is widely considered a possible approach for maintaining soil biodiversity and a healthy functioning ecosystem. Here we aim to examine the effects of organic fertilizer on AMF occurrence. Methods We conducted a meta-analysis of 162 field experiments from 54 published studies conducted over the last 20 years. Our dataset included two groups: organic fertilization (OF) vs chemical-only fertilization (CF) and OF vs no fertilization (NF). Results We found that organic fertilizer increased AM fungal biomass and was less detrimental to AMF richness than mineral-only fertilization. AMF responses to organic fertilizer were generally positive when AMF and host plants had a strong mutualistic symbiosis such as in phosphorus-deficient soil, drought and semi-drought areas, at low latitudes, and at testing sites that contained two or more plant species or included legume. In conditions other than these, the responses were generally negative. Organic carbon input, increased soil phosphorus and the ratio of fertilizer N and P jointly explain the effects of organic fertilizer on AMF occurrence. Conclusions Our analysis indicates that, although some limiting factors exist, application of organic fertilizer can be an effective practice to protect AM symbiosis from the negative effects of nutrient enrichment in current cropping systems.
18. 题目: Maize genotype-specific exudation strategies: an adaptive mechanism to increase microbial activity in the rhizosphere
期刊: Soil Biology and Biochemistry
作者: Nataliya Bilyera, Xuechen Zhang, Patrick Duddek, Lichao Fan, Callum C. Banfield, Steffen Schlüter, Andrea Carminati, Anders Kaestner, Mutez A. Ahmed, Yakov Kuzyakov, Michaela A. Dippold, Sandra Spielvogel, Bahar S. Razavi
摘要: Plants stimulate microbial enzyme production in the rhizosphere, regulating soil organic matter decomposition and nutrient cycling. The availability of labile organic compounds (i.e. exudates) and water is the main prerequisite for such microbial activity and enzyme production, thus shaping the rhizosphere. Root morphology (i.e., root hairs) and exudate composition define the spatial distribution of properties and functions in the rhizosphere. However, the role of root architecture and exudate composition in this spatial self-organization of the rhizosphere remains unknown. We coupled three in situ imaging approaches: 14C imaging to localize exudates, soil zymography to analyze enzyme activity distribution, and neutron radiography for water fluxes to trace the spatial structure of the rhizosphere of three maize genotypes (wild-type, mutant with defective root-hair prolongation rth3, and mutant with reduced benzoxazinoid content in root exudates bx1). The co-localization of these three soil images revealed the pivotal role of both optimal water content (neutron radiography) and root exudation (14C imaging) for β-glucosidase production by the rhizosphere microbiome and its hydrolytic activity (zymography). Root hairs increased the exudate release and enlarged the spatial extent of increased β-glucosidase activity around the root axis by 35 %, leading to a two-fold faster decomposition of 14C exudates compared to the mutant with defective root hairs. In contrast, benzoxazinoids suppressed β-glucosidase activity by 30 %, reflecting decreased microbial activity, whereas their absence broadened the rhizosphere. Overall, root hairs in wild type maize increased microbial activity (i.e. β-glucosidase production), whereas the benzoxazinoids in root exudates suppressed microorganisms.
19. 题目: Sequential ClO2-UV/chlorine process for micropollutant removal and disinfection byproduct control
期刊: Science of The Total Environment
作者: Mengge Fan, Xin Yang, Qingqing Kong, Yu Lei, Xinran Zhang, Ehsan Aghdam, Ran Yin, Chii Shang
摘要: This study systematically revealed the feasibility of the sequential ClO2-UV/chlorine process for micropollutant removal and disinfection byproduct (DBP) control. The results demonstrated that the sequential ClO2-UV/chlorine process was effective for the removal of 12 micropollutants. ClO2 pre-treatment reduced the formation of disinfect byproducts (DBPs) in the UV/chlorine process. Compared to the UV/chlorine process, ClO2 pre-treatment (1.0 mg L−1) decreased the formation of the 6 DBPs by 25.1–72.2%; and decreased the formation potential of the 6 DBPs by 13.9–51.8%. Moreover, ClO2 pre-treatment reduced the concentration of total organic chlorine by 19.8%. ClO2 pre-treatment affected the UV/chlorine process in different ways. Firstly, ClO2 pre-treatment generated chlorite, which dominantly served as a scavenger of chlorine radical (Cl￼) and hydroxyl radical (HO￼). Secondly, ClO2 pre-treatment decreased the reactivity of natural organic matter (NOM) towards radicals. Finally, ClO2 pre-treatment altered the properties of NOM, in terms of reducing the electron-donating capacity and aromaticity of NOM (SUVA254), and slightly reducing the average molecular weight of NOM. Overall, ClO2 pre-treatment effectively controlled the formation of DBPs in the UV/chlorine process. This study confirmed the sequential ClO2-UV/chlorine process was an alternative strategy to balancing the micropollutant removal and DBP control.
20. 题目: Obtaining high-value nitrogen-containing carbon nanosheets with ultrahigh surface area from waste sludge for energy storage and wastewater treatment
期刊: Science of The Total Environment
作者: Zhengliang Du, Qiandi Wang, Youjing Du, Qiongying Xu, Dongsheng Wang, Weijun Zhang
摘要: Recovering high value-added resources from waste activated sludge (WAS) is a potential way for the sustainable wastewater treatment. In this study, hydrothermal treatment at 180 °C was used to simultaneously improve sludge dewaterability and recover sludge organic matters (SOMs). The recovered SOMs were subsequently employed as precursors to prepare nitrogen-doped porous carbon nanosheets via a facile stepwise synthesis method. The as-prepared optimal carbon (AP-SOM800) was characterized with an ultrahigh specific surface area (3473 m2/g), appropriate porosity (1.77 cm3/g), and abundant heteroatoms (1.47% N and 7.44% O). AP-SOM800 exhibited a high specific capacitance (409 F/g at 0.25 A/g), low resistance (0.52 Ω), and superior cyclic stability (only 9.09% loss after 10,000 cycles) in 6 M KOH aqueous electrolyte. Furthermore, AP-SOM800 demonstrated an extraordinary adsorption capacity (1528 mg/g for methyl orange (MO) and 1265 mg/g for tetracycline (TC)) that can be maintained (˃1200 mg/g) over a wide range of pH conditions. Specifically, 80.97% of MO and 66.67% of TC were rapidly absorbed through AP-SOM800 within 10 min, and 90.27% of MO and 81.24% of TC were eventually removed from wastewater after 60 min. The adsorption processes fit closely with the pseudo-second-order kinetic (R2 > 0.999) and Langmuir models (R2 > 0.914), revealing that the adsorption processes were dominated by a monolayer chemical adsorption reaction. This study suggests that high value-added materials can be obtained from the WAS through improving and extending the traditional sludge treatment processes, which will enrich the technical options available for future sustainable sludge treatment and disposal.