41. 题目: Element mobility related to rock weathering and soil formation at the westward side of the southernmost Patagonian Andes
期刊: Science of The Total Environment
作者: Björn Klaes, Gerhard Wörner, Sören Thiele-Bruhn, Helge Wolfgang Arz, Julian Struck, Olaf Dellwig, Nora Groschopf, Marcel Lorenz, Jean-Frank Wagner, Oscar Baeza Urrea, Frank Lamy, Rolf Kilian
摘要: Rock weathering and pedogenesis are fundamental processes for element mobility in terrestrial bio-geochemical cycles and for the regulation of primary productivity in adjacent coastal marine ecosystems. Here, soils developed from volcanic ash under extreme climate conditions could play a particular role. We therefore investigated rock weathering, soil formation and the associated mobilization of trace elements and micronutrients in a pristine South Patagonian ecosystem. Weathered and unweathered basement lithologies, tephra of the 4.216 kyrs BP Mt. Burney eruption and four soil profiles are considered. The approach combines mineralogical (XRD, SEM) and inorganic geochemical (XRF, ICP-OES/MS) with organic geochemical analyses (TOC, TN, δ13C, δ15N, DOC extracts) of representative samples. Chemical weathering is quantified by mass balance calculations and 14C age constraints allow a correlation of pedogenic processes with the paleoenvironmental history of the area. Our data document that pedogenesis with initial peat formation occurred since ~2.5 kyrs BP. In these acidic peaty Andosols, intensive alteration of volcanic glass mobilized large quantities of elements, considerably surpassing leachates provided by basement rock weathering. Clay production is limited in favor of the formation of amorphous Al- and crystalline Fe-(hydr)oxides. However, tephra alteration, soil organic matter turnover rates, enhanced dissolved organic carbon export, and Fe-/Al-(hydr)oxide precipitation are closely linked and ultimately controlled by rainfall-induced water-level fluctuations, highlighting the dominant influence of the southern westerly wind belt. The transport of mobilized trace elements and micronutrients adsorbed onto suspended colloids (dissolved organic carbon, Al-humus complexes and Fe-(hydr)oxides) is redox-pH-dependent, highly variable and ultimately regulated by westerly intensity. Broader implications of this work include a new perspective on the climate-controlled micronutrient delivery for primary productivity in South Patagonian fjords, which is strongly affected by Andosol formation. Furthermore, a careful evaluation of ‘ordinary’ geochemical proxies in regional paleoenvironmental archives is needed to account for these unique pedogenic processes.
42. 题目: Detailing the organic matter in suspended sediments as a tool to assess the impact of land occupation in water bodies: a case of Barigui Watershed (Southern Brazil)
期刊: Environmental Geochemistry and Health
作者: Angela Ethelis Jimenez Martinez, Sandro Froehner, Daniel Macedo Neto, Carlos Eduardo Galoski
摘要: Suspended sediments were collected to examine the organic carbon content and n-alkanes in order to assess the impact on water bodies caused by soil and land occupation. For this, samples from distinct areas based on the level of land occupation of the Barigui Watershed and different areas under the influence of human activities were examined. The number of industries increasing along the river was also considered. Twenty-two sediment samples were collected using a time-integrated sediment sampler. Samples were extracted with dichloromethane:methanol (DCM:methanol) (2:1) in an ultrasound bath, treated and injected using gas chromatography coupled with mass spectrometry (GC-MS) for separation and quantification. Twenty-one n-alkanes were identified and were used to track both biogenic and anthropogenic inputs. The concentration of total n-alkanes varied from 38.72 to 222.76 µg g-1, due to the impact of urbanization. Diagnostic indexes indicated high numbers of plants, bacteria and petroleum as n-alkanes sources. The following results were obtained using: carbon preference index (CPI), 1.96-2.22 (rainy season) and 2.12-5.80 (summer season); average chain length (ACL), 30.37-31.17 (rainy season) and 30.05-30.50 (summer season) and terrigenous aquatic ratio (TAR), 0.39-5.47 (rainy season) and 2.98-5.06 (summer season); n-alkanes had two main sources: terrestrial plant and petroleum. It is clear that the source of n-alkanes is different in each season (rainy and dry) demonstrated by n-alkanes occurrence. During the rainy season, there was an increase in organic matter of oil origin which was mainly associated with the increased runoff and rain drainage. Finally, the input of organic matter associated with land occupation and erosion can be distinguished by higher concentration in the most urbanized site (PB).
43. 题目: Efficient adsorptive removal of fluoroquinolone antibiotics from water by alkali and bimetallic salts co-hydrothermally modified sludge biochar
期刊: Environmental Pollution
作者: Yongfei Ma, Tingmei Lu, Lie Yang, Li Wu, Ping Li, Jiayi Tang, Yulin Chen, Feng Gao, Song Cui, Xuebin Qi, Zulin Zhang
摘要: Fluoroquinolones are one of most commonly used antibiotics for preventing and treating bacterial infections and their unsatisfactory removal by conventional wastewater treatment technology have aroused widespread attention. A novel adsorbent of KMSBC was the first time synthesized and tested to adsorb three typical fluoroquinolone antibiotics of CIP, NOR and OFL from water. The characterization analysis showed that KMSBC possessed the superior porous structure, abundant functional groups and greater graphitic degree. Together with kinetics, isotherms, thermodynamics and critical factors (e.g., biochar dose, reaction time/temperature, fluoroquinolone antibiotics concentration, pH, co-existing ionic strength and HA concentration) analysis suggested that pore filling, π-π conjugation, H-bonding and electrostatic interaction were the key mechanisms for fluoroquinolone antibiotics adsorption by KMSBC. KMSBC exhibited the optimum adsorption performance at pH = 5 despite the adsorbates. The maximum adsorption capacity of KMSBC for CIP, NOR and OFL were 49.9, 55.7 and 47.4 mg/g at 25 °C, respectively. Also, KMSBC exhibited the good magnetic sensitivity and stability with the leaching concentrations of Fe were far below than environmental limit (GB5749-2006) at various pH (from 3 to 12), ionic strength and HA concentrations. Additionally, KMSBC performed a stable sustainable adsorption performance in recycles by NaOH regeneration. Thus, KMSBC had the potential to be a promising adsorbent for fluoroquinolone antibiotics removal with favorable adsorption capacity, environmental security and easy regeneration performance.
44. 题目: Effects of competitive adsorption with Ni(II) and Cu(II) on the adsorption of Cd(II) by modified biochar co-aged with acidic soil
作者: Zhuowen Meng, Ting Xu, Shuang Huang, Haimeng Ge, Wenting Mu, Zhongbing Lin
摘要: To investigate the effects of competitive adsorption with Ni(II) and Cu(II) on the adsorption of Cd(II) by modified biochar co-aged with acidic soil, four biochars were employed in this study, namely original biochar, KMnO4-modified biochar and two aged biochars which co-aged with an acidic soil using above biochars under freeze-thaw cycling and dry-wet cycling for 54 days simulating 6 years of natural aging. The results showed that biochar adsorption capacities of three heavy metal ions were in the order of Cd(II) > Cu(II) > Ni(II) in the single system while Cu(II) > Cd(II) > Ni(II) in binary and ternary systems. Modification improved biochar adsorption capacity of Cd(II), but competitive adsorption with Ni(II) and Cu(II) weakened the improvement of modification on adsorption performance of modified biochar in binary and ternary systems. The QMBC/QBC of Cd(II) (QMBC and QBC are the adsorption capacities of heavy metals by modified and original biochars) decreased from 231.57% (single system) to 216.67%∼219.41% (binary system) and further decreased to 207.74% (ternary system). Co-aging with soil weakened the adsorption capacities of biochars for Cd(II), even worse, competition aggravated this negative effect of co-aging. The QAMBC/QMBC of Cd(II) (QAMBC is the adsorption capacities of heavy metals by aged modified biochar) decreased from 65.41% (single system) to 14.43%∼19.46% (binary and ternary systems). Therefore, the impact of competition should be fully considered when evaluating Cd long-term remediation effects of modified biochar in Cd polluted soils accompanied with other heavy metals.
45. 题目: Use of biochar to manage soil salts and water: Effects and mechanisms
作者: Xinqing Lee, Fang Yang, Ying Xing, Yimin Huang, Liang Xu, Zhongtang Liu, Ran Holtzman, Iddo Kan, Yunlong Li, Like Zhang, Hui Zhou
摘要: Soil salinization is a widespread land degredation, especially in water-stressed regions, jeopardizing agriculture sustainability. Current desalinization methodology involves excessive water consumption. Biochar has the potential to mitigate soil salinization while increasing water holding capacity. As a saline and sodic material, however, how it works and whether it can be used to sustain the agriculture at reduced water resource remain to be studied. Here, by monitoring transport of water, salts and nutrients in the profile of irrigation-silt soil during watering and evaporation in both laboratory and field in Kashgar oasis, Xinjiang, China, we find biochar exacerbates salinization upon application. This is changed, however, after several cycles of irrigation-evaporation due to strengthened salt leaching in irrigation and salt removal out of the depth through intensified top accumulation by evaporation, both resulting from increased capillary effect and thereby the enhanced movement of salts despite the competing electrical adsorption to the cations. The resulted salt distribution facilitates desalinization by removing the top 2 cm soil. Biochar also promotes evaporation after irrigation due to inceased water content and capillary suction. This is reversed once the soil cracks, a common phemomenon in irrigated land. Biochar counteracts the cracking through alleviation of soil compaction, saving tillage while lowering water evaporation, e.g., by 43% at 10% biochar. Our findings indicate that application of biochar changes salt distribution, enabling desalinization with little water consumption. Together with the effect of anti-fracturing and enhanced salt leaching, it lowers water demand substantially, providing a novel solution for agricultural sustainability in salt-affected regions.
46. 题目: Adsorption mechanisms for cadmium from aqueous solutions by oxidant-modified biochar derived from Platanus orientalis Linn leaves
期刊: Journal of Hazardous Materials
作者: Kaiyue Yin, Juyuan Wang, Sheng Zhai, Xin Xu, Tingting Li, Shuchen Sun, Shuai Xu, Xuexue Zhang, Cuiping Wang, Yingshu Hao
摘要: To understand the adsorption mechanisms of Cd2+ by oxidant-modified biochar (OMB) derived from Platanus orientalis Linn (POL) leaves, batch adsorption experiments and characterization were carried out. The results showed that, KMnO4-modified biochar (MBC) could more effectively remove Cd2+ from aqueous solution than H2O-, H2O2-, and K2Cr2O7-modified biochar (WBC, HBC and PBC, respectively). The highest removal efficiency was 98.57%, which was achieved by the addition of 2gL-1 MBC at pH 6.0. According to the Langmuir fitting parameters, the maximum adsorption capacity for MBC was 52.5mgg-1 at 30 ℃, which was twice as high as that for original biochar. MBC had the largest specific surface area with many particles distributed on the surface before and after adsorption, which were confirmed to be MnOx by XPS analysis. The complexation with MnOx was the main mechanism. Besides, O-containing groups complexation, precipitation, cation-π intraction, and ion exchange also participated in the adsorption. However, WBC, HBC and PBC did not achieve ideal removal effects, and their stability was inferior. This could be attributed to the weakening of ion exchange and precipitation. This study not only demonstrates the potential of MBC, but also provides insight into strategies for the utilization of waste resources.
47. 题目: Hydrophobicity of soils affected by fires: An assessment using molecular markers from ultra-high resolution mass spectrometry
期刊: Science of The Total Environment
作者: Nicasio T. Jiménez-Morillo, Gonzalo Almendros, Ana Z. Miller, Patrick G. Hatcher, José A. González-Pérez
摘要: Soil water repellency (SWR) is a physical property due to a complex interaction of factors (e.g., fire, soil organic matter, soil texture) that reduces the soil water infiltration capacity. Traditionally, SWR is attributed to the accumulation and redistribution of hydrophobic compounds within soil profile. To obtain further insight into chemical compounds, which could be associated with SWR, a study was done on coarse (1–2 mm) and fine (< 0.05 mm) granulometric fractions of burned and unburned sandy soils under two Mediterranean vegetation biomes from Doñana National Park (Spain). The water drop penetration time (WDPT) test was used to assess the SWR. The molecular composition of extracted humic substances from the soil organic matter (SOM) was determined by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). Partial least squares (PLS) regressions showed that the SWR can be predicted (P = 0.006) solely based on the abundances of approximately 1200 common compounds determined by FT-ICR/MS. This model confirmed the significant correlation between a specific SOM molecular composition and the SWR. The comparative analysis revealed that the SWR in the burned samples was significantly (P < 0.05) related to the abundance of aromatic and condensed compounds, while in the unburned samples there was a significant influence of aromatic hydrocarbons and lignin compounds. In the fine fraction, lipid compounds were significantly associated with the SWR. Contrastingly, the coarse fraction did not show any correlation. Alternatively, soils with a high SWR were significantly related to the presence of lipids and lignin. This analysis showed that combining FT-ICR/MS molecular characterizations with statistical treatments is a powerful approach for exploratory analysis suggesting that the structural features associated with SWR in the studied soils are different depending on the types of vegetation or the soil physical fractions with different particle size.
48. 题目: O, N-doped porous biochar by air oxidation for enhancing heavy metal removal: The role of O, N functional groups
作者: Viet Cuong Dinh, Chia-Hung Hou, Thuy Ninh Dao
摘要: Oxygen- and nitrogen-doped porous oxidized biochar (O,N-doped OBC) was fabricated in this study. Biochar (BC) can be enriched in surface functional groups (O and N) and the porosity can be improved by a simple, convenient and green procedure. BC was oxidized at 200 °C in an air atmosphere with quality control via oxidation time changes. As the oxidation time increased, the O and N contents and porosity of the materials improved. After 1.5 h of oxidation, the O and N contents of O,N-doped OBC-1.5 were 54.4% and 3.9%, higher than those of BC, which were 33.4% and 1.8%, respectively. The specific surface area and pore volume of O,N-doped OBC-1.5 were 88.5 m2 g−1 and 0.07 cm3 g−1, respectively, which were greater than those of BC. The improved surface functionality and porosity resulted in an increased heavy metal removal efficiency. As a result, the maximum adsorption capacity of Cu(II) by O,N-doped OBC was 23.32 mg L−1, which was twofold higher than that of pristine BC. Additionally, for a multiple ion solution, O,N-doped OBC-1.5 showed a greater adsorption behavior toward Cu(II) than Zn(II) and Ni(II). In a batch experiment, the concentration of Cu(II) decreased 92.3% after 90 min. In a filtration experiment, the O,N-doped OBC-based filter achieved a Cu(II) removal capacity of 12.90 mg g−1 and breakthrough time after 250 min. Importantly, the chemical mechanism was mainly governed by monolayer adsorption of Cu(II) onto a homogeneous surface of O,N-doped OBC-1.5. Surface complexation and electrostatic attraction were considered to be the chemical mechanisms governing the adsorption process.
49. 题目: An overview of sulfur-functional groups in biochar from pyrolysis of biomass
期刊: Journal of Environmental Chemical Engineering
作者: Lijian Leng, Renfeng Liu, Siyu Xu, Badr A. Mohamed, Zequn Yang, Yingchao Hu, Jiefeng Chen, Shilin Zhao, Zhibin Wu, Haoyi Peng, Hui Li, Hailong Li
摘要: Biochar is a solid material obtained from the pyrolytic carbonization of biomass in an oxygen-free/limited environment. Sulfur-containing biochar has a wide range of applications, such as adsorptive removal of pollutants (e.g., Hg, Cd, and Ni) and acting as a solid acid catalyst or as an electrode of Li-S battery. To date, many methods have been developed to strengthen the function of biochar by introducing sulfur-containing groups to promote the application and commercialization of biochar. This review aims to present the formation, analysis, engineering, and application of sulfur-functional groups in biochar. The sulfur-functional groups such as organic sulfur (e.g., C–S, –C–S–C–, C=S, thiophene, and sulfone) and inorganic sulfate (e.g., sulfate, sulfide, sulfite, and elemental S) can be determined through Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray absorption near edge structure (XANES). The sulfur-functional groups can be obtained through selecting biomass composition, pyrolysis process, S-doping, and post-treatment of biochar, but the engineering is challenging. The positive effect of sulfur-functional groups in the application is also analyzed in this paper, such as the complexation and electron transfer between sulfur-functional groups and heavy metal (e.g., Hg, Cd, and Ni) on improving biochar adsorption capacity. However, there are still challenges in directional synthesis, precise determination, and regulation of application performance. Based on the research gaps identified, future prospective investigation directions on analysis, engineering, and application of biochar S-functional groups were presented in this review.
50. 题目: Forest expansion on cropland on China’s Loess Plateau facilitates C sequestration by increasing microbial-derived but not plant-derived carbohydrates
作者: Qingyin Zhang, Xiaoxu Jia, Tongchuan Li, Mingan Shao, Xiaorong Wei, Nan Zhang
摘要: Conversion of cropland to forest affects the microbial transformation of plant-derived organic substances and the accumulation of microbially synthesized products in soil. Labile litter represents the major source for soil microbial products, which promote soil aggregation and long-term carbon (C) stabilization. The present study investigated the changes in carbohydrate monosaccharides and their origins (i.e., microbial-derived or plant-derived carbohydrates) following the afforestation of cropland in the Loess Plateau region by Robinia pseudoacacia. Carbohydrate monosaccharides were determined in the soil fractions and plant organs in cropland and four R. pseudoacacia forests aged 5, 12, 25, and 32 years. The distributions of the soil aggregates and their stability were also measured. Forest expansion on cropland significantly increased the total organic C in the 0–10 cm soil layer by 31.8%. Glucose was the dominant monosaccharide in the plants and all soil fractions from all R. pseudoacacia forests, followed by galactose, xylose, and mannose. Following 32 years of afforestation, the ratios of microbial-derived carbohydrates relative to plant-derived carbohydrates (such as R(Rhamnose + Fucose)/(Arabinose + Xylose)) significantly increased by 131%, 149%, and 86% in the particulate organic matter, stable aggregate, and silt and clay fractions, respectively. Significant and positive correlations were found between the aggregate stability indexes and microbial-derived monosaccharides, thereby indicating that microbial-derived monosaccharides may play key roles in the stabilization of soil aggregates. These results suggest that following forest expansion on cropland, the increasing amounts of microbially-derived compounds corresponding to the increased allocation of soil C to stable aggregates may promote soil aggregation.
51. 题目: Identifying carbon processing based on molecular differences between groundwater and water-extractable aquifer sediment dissolved organic matter in a Quaternary alluvial-lacustrine aquifer
期刊: Applied Geochemistry
作者: Qi Zhao, Yiqun Gan, Yamin Deng, Haoran Zhou, Huamiao Zhao
摘要: Dissolved organic matter in groundwater (GDOM) plays an important role in many biogeochemical processes. The molecular composition of GDOM varies with the source and processing pathways, and also affects its reactivity. Sedimentary organic matter (SOM) is a key carbon source in groundwater, but its association with GDOM remains unclear. In this study, Fourier transform-ion cyclotron resonance-mass spectrometry (FT-ICR-MS) and comprehensive data analysis were used to identify the molecular characteristics of SOM and the fate of DOM in groundwater by comparing the differences between the GDOM with depth-matched water-extractable aquifer SOM (WEOM; the most bioavailable and dynamic pool of organic carbon in SOM) in a Quaternary alluvial-lacustrine aquifer with abundant SOM in Jianghan Plain, central China. The results show that WEOM is a key carbon source in groundwater as reflected by the strong correlation (rs = 0.76, P = 0.028) of the DOC content between GDOM and WEOM, and the large proportion (70.64 ± 14.09%) of common compounds present both in GDOM and WEOM. However, the molecular compositions of GDOM and WEOM are significantly different even for common compounds when considering the relative abundance. WEOM contains relatively high abundance of low molecular weight and thermodynamically more favorable components for microbial oxidation (aminosugars and carbohydrates), making WEOM an energetic carbon source for groundwater that can fuel reduction half-reactions such as iron oxide reduction. Although the hydrochemical compositions and the DOC content of groundwater are quite different, the molecular composition of GDOM is relatively similar and enriched in oxygen-poor highly unsaturated and phenolic compounds compared with WEOM. This indicates that organic matter is gradually processed into stable components with relatively medium aromaticity, low average nominal carbon oxidation state, low O/C and medium H/C; these transformations occur through adsorption to minerals and biodegradation after being mobilized from aquifer sediment into groundwater. We identified the processing pathways of GDOM based on comprehensive comparisons of molecular compositions between aquifer WEOM and GDOM, and highlight the combined influence of aquifer SOM and processing pathways on the GDOM molecular compositions in the alluvial-lacustrine aquifer with abundant aquifer SOM.
52. 题目: Treatment of organic matter and ammonia nitrogen in wastewater by electrocatalytic oxidation: a review of anode material preparation
期刊: Environmental Science: Water Research & Technology
作者: Hailong Jing, Haitao Yang, Xiaohua Yu, Chaoquan Hu, Rongxing Li, Hongtao Li
摘要: The research progress of electrochemical treatment of organic matter and ammonia nitrogen in wastewater is reviewed in this work. Ti/Pt, Ti/RuxIryOz, Ti/IrO2–Ta2O5, Ti/PbO2, TinO2n−1, Ti/SnO2–Sb, boron-doped diamond, graphite, and particle electrodes were introduced. The different types of electrodes were produced primarily by thermal decomposition, electrochemical deposition, sol–gel, and chemical vapor deposition, including the pretreatment of matrix materials and coating. The degradation efficiency of organic matter (this paper primarily discusses rhodamine B [RHB] and phenol) and ammonia nitrogen in wastewater under the optimal reaction conditions was summarized. The reaction mechanism of electrochemical degradation of organic matter and ammonia nitrogen was analyzed, which is the direct electron transfer on the anode surface or the action of the strong oxidizing ˙OH radical generated by the indirect oxidation reaction. In addition, some new electrodes, such as nanostructured electrodes and porous electrodes, were used to degrade pollutants in wastewater treatment.
53. 题目: Protein cycling in the eastern tropical North Pacific oxygen‐deficient zone: A de novo‐discovery peptidomic approach
期刊: Limnology and Oceanography
作者: Megan E. Duffy, Jacquelyn A. Neibauer, Jamee Adams, Rachel A. Lundeen, Gabrielle Rocap, Anitra E. Ingalls, Clara A. Fuchsman, Richard G. Keil
摘要: Peptides are identified using a de novo-discovery approach in suspended and sinking particles from the eastern tropical North Pacific oxygen-deficient zone (ODZ) and in a culture of a dominant autotroph from the region, the cyanobacterium Prochlorococcus. The benchmarking experiment with Prochlorococcus shows de novo peptides to be taxonomically specific, and thus of value in augmenting database-driven approaches. Analysis of the suspended and sinking particles using the de novo-discovery approach reveals the presence of fungal proteins in deep sinking particles that were not in our original search database, contributing to growing recognition that fungi may play important roles in marine organic matter cycling. Cyanobacterial peptides that have been post-translationally modified were tracked to depth, where they contribute ~ 1% of the phylum-level identifiable peptide pool in the sediment trap sample. The majority of peptides found at depth in the detrital pool are associated with membranes, indicating that cellular location is associated with early preservation within the detrital pool. Modified amino acids in sinking and suspended particles include high levels of deamidation, suggesting that partial extracellular degradation of protein could fuel observed anammox and contribute to pools of refractory organic nitrogen.
54. 题目: Soil carbon stocks and dynamics of different land uses in Italy using the LUCAS soil database
期刊: Journal of Environmental Management
作者: Md. Zulfikar Khan, Tommaso Chiti
摘要: In terrestrial biosphere, soil represents the largest organic carbon pool, and a small change of soil organic carbon (SOC) can significantly affect the global carbon cycle and climate. Land use change (LUC) and soil management practices coupled with climate variables can significantly influence the soil organic carbon stocks (SOC–S) and its dynamics; however, our understanding about the responses of SOC in different LUC's (e.g., cropland, grassland and forest land) to mitigate climate change is quite limited at country level like Italy. Thus, the aims of this study were which factors are affecting SOC dynamics in three LUC's over time across Italy; and their relevance in terms of SOC–S in the superficial layer of soil that significantly contributes to the climate change mitigation, using LUCAS soil database. To calculate the SOC–S, it is necessary to have soil bulk density (BD) which is not present in the LUCAS database. Thus, we estimate the soil BD using the pedotransfer function (PTFs); and results shows that the soil BD obtained from fitting of the PTFs were reasonable to estimate the SOC–S for different land use types (R2 ≥ 0.75). Overall, results showed that LUC's and soil management practices can significantly (p < 0.001) influences SOC dynamics and SOC storage from the soil and varied among LUC's but not for over time except grassland. Spatially, the mean SOC–S storage of the different LUC's was in the following order: forest land > grassland > cropland for both years 2009 and 2015. On the other hand, the SOC–S storage increased by 8.33% for cropland, 13.56% for forest land, and 29.79% for grassland during the year of 2009–2015, while SOC–S storage increased significantly (p < 0.001) in grassland over time but not for cropland and forest land which also follow the increasing trend but insignificantly. Our results also reveal that the SOC dynamics negatively correlated with MAT, and positively correlated with MAP for all land uses except forest land. Thus, this research indicates that LUC's and soil management practices coupled with climate variables can significantly influence SOC storage and its dynamics in the superficial layer of soil which have the potential capacity to mitigate climate change.
55. 题目: Spatial distribution and nitrogen metabolism behaviors of anammox biofilms in bioelectrochemical system regulated by continuous/intermittent weak electrical stimulation
期刊: Journal of Cleaner Production
作者: Cai Teng, Lu Xueqin, Zhongyi Zhang, Wanjiang Li, Na Wang, Yizhi Zhang, Ruiliang Zhang, Guangyin Zhen
摘要: A bioelectrochemical anammox system (BEAnS) was constructed and operated at low temperature to investigate the effect of weak electrical stimulation (continuous or intermittent) on metabolism behaviors, electrochemical activity, nitrogen removal, and spatial distribution of anammox biofilms. Results showed that the continuously stimulated biocathode exhibited the highest electron transfer system activity (34.2 ± 6.9 μg mg−1 h−1), the fastest electron transfer coefficient (0.0412 s−1), the largest current density (0.25 A cm−2), and the smallest polarization resistance (∼4 Ω). This led to an enhanced nitrogen removal of 60.6 ± 5.6% and energy recovery of 289.1 mW m−3, compared with those of the control. Confocal laser scanning microscopy and fluorescence in situ hybridization analysis confirmed that continuous weak electrical stimulation could accelerate the secretion of extracellular polymer substances, which facilitated the aggregation/adhesion of single cell and subsequent development of compact and stratified co-existing biofilms on cathode. Microbial analysis further demonstrated the proliferation of electrotrophic denitrifying microorganisms (i.e., Thauera, Hydrogenophaga, and Ignavibacterium), nitrifier (Candidatus_Nitrotoga), and denitrifier (Denitratisoma), except for anammox bacteria (i.e., Candidatus_Brocadia, and Candidatus_Jettenia), implying the critical role of weak electrical stimulation in diversifying N-degrading microbial community and creating a more robust nitrogen metabolic pathway. These findings can provide a novel insight into autotrophic electroactive anammox biofilm enrichment and their activity enhancement by weak electrical stimulation.
56. 题目: Transport of silver nanoparticles coated with polyvinylpyrrolidone of various molecular sizes in porous media: Interplay of polymeric coatings and chemically heterogeneous surfaces
期刊: Journal of Hazardous Materials
作者: Kunkun Wang, Yi Ma, Binbin Sun, Yi Yang, Yinqing Zhang, Lingyan Zhu
摘要: Silver nanoparticles (AgNPs) are usually capped with stabilizing agents to protect their activities and improve stability. Polyvinylpyrrolidone (PVP) is one of the most used capping agents of AgNPs, and may affect the transport of AgNPs in porous media. The transport and retention of AgNPs capped with PVPs of different molecular weights (PVP10-AgNP, PVP40-AgNP and PVP360-AgNP) in uncoated, and humic acid (HA)-, kaolinite (KL)- and ferrihydrite (FH)-coated sand porous media were investigated. Among the three AgNPs, PVP360-AgNP exhibited the highest mobility and eluted from all types of porous media. This is because PVPs of higher molecular weight provided stronger steric effect and electrostatic repulsive forces among PVP-AgNPs, inducing stronger blocking and shadow effects. The transport of the PVP-AgNPs increased in the HA-Sand columns, while decreased in the KL- and FH-Sand columns, especially for PVP10-AgNP and PVP40-AgNP. The simulation results using one-site kinetic model indicated that HA-Sand reduced the maximum retention capacity (Smax), while KL- and FH-Sand increased the Smax as well as the first-order attachment rate coefficients (katt), particularly at high ionic strength. The results shed light on the interplay of the capping agents of AgNPs and the surface heterogeneity on the transport of AgNPs in porous media.
57. 题目: Benthic Biofilm Potential for Organic Carbon Accumulation in Salt Marsh Sediments
作者: Kendall Valentine, Abbey Hotard, Tracy Elsey-Quirk, Giulio Mariotti
摘要: Coastal salt marshes are productive environments with high potential for carbon accumulation and storage. Even though organic carbon in salt marsh sediment is typically attributed to plant biomass, it can also be produced by benthic photosynthetic biofilms. These biofilms, generally composed of diatoms and their secretions, are known for their high primary productivity and contribution to the basal food web. The growth of biofilms and the preservation of carbon produced by biofilms depends on the amount of sedimentation; low sedimentation rates will favor decomposition, while high sedimentation rates could decrease biofilm productivity. In this study, we conducted laboratory experiments to test (1) if biofilms can potentially accumulate carbon in marsh soil and (2) how different sedimentation rates affect the amount of carbon accumulation. Containers filled with a settled mud bed were inoculated with natural biofilms collected from a marsh surface and allowed to grow with favorable light exposure, nutrient supply, and absence of grazing. Mud was added weekly in different amounts, resulting in an equivalent sedimentation rate from 12 to 189 mm/yr. After 11 weeks, the sediment columns were sampled and analyzed for chl a, organic matter via loss on ignition (LOI), and total organic carbon (TOC). Chl a accumulation rates ranged from 123 to 534 mg/cm2/yr, organic matter accumulation ranged from 86 to 456 g/m2/yr, and TOC accumulation rates ranged from 31 to 211 g/m2/yr. These values are on the same order of magnitude of marsh carbon accumulation rates measured in the field. All three metrics (chl a, organic matter, and TOC) increased with increased sedimentation rate. These results show that biofilms can potentially contribute to carbon accumulation in salt marsh soils. Furthermore, areas with high sedimentation rates have the potential for higher amounts of organic matter from biofilms in the sediment.
58. 题目: Improved removal performance of Gram-negative and Gram-positive bacteria in sand filtration system with arginine modified biochar amendment
期刊: Water Research
作者: Mengya Zhang, Lei He, Xiangwei Zhang, Shuai Wang, Boaiqi Zhang, Lichun Hsieh, Kun Yang, Meiping Tong
摘要: Bacterial removal by sand filtration system is commonly inefficient due to the low bacterial adsorption capacity of sand. To improve the bacterial removal performance, biochar fabricated at different temperatures (400 °C, 550 °C and 700 °C) and arginine modified biochar were added into sand filtration columns as filter layers (0.5 and 1 wt%). Addition of biochar into sand columns could improve the removal efficiency for both Escherichia coli and Bacillus subtilis under both slow (4 m/day) and fast (240 m/day) filtration conditions. Bacterial removal efficiency in sand columns with the addition of biochar fabricated at 700 °C were higher than those fabricated at 400 °C and 550 °C due to its best bacterial adsorption capacity. Modification of biochar with arginine could further improve the bacterial removal performance. Specifically, complete bacterial removal (1.35 × 107 ± 10% cells/mL) could be achieved under both slow and fast filtration conditions in sand columns with 1 wt% arginine functionalized biochar amendment. The enhanced bacterial adsorption capacity mainly contributed to the increased bacterial capture performance in columns with addition of arginine-modified biochar. Bacteria more tightly bounded with arginine-modified biochar than bulk biochar. Moreover, complete bacterial removal with the copresence of 5 mg/L humic acid in suspensions was acquired in columns with addition of 1 wt% arginine-modified biochar. Efficient bacterial removal in actual river water, multiple filtration cycles as well as longtime injection duration (100 pore volumes injection) was also obtained. The results of this study demonstrated that arginine-modified biochar had great potential to treat water contaminated by pathogenic bacteria.
59. 题目: The coupling interaction of soil organic carbon stock and water storage after vegetation restoration on the Loess Plateau, China
期刊: Journal of Environmental Management
作者: Yuxuan Chen, Tianxing Wei, Kang Ren, Guoliang Sha, Xin Guo, Yanchao Fu, Huan Yu
摘要: Vegetation restoration may increase the soil organic carbon stock (SOCS) but decrease the soil water storage (SWS) of terrestrial ecosystems in arid and semiarid regions. To guarantee the sustainability of restoration, it is critical to evaluate the coupling interaction of SOCS and SWS. Here, we examined the spatial distributions of SOCS and SWS across a 0–200 cm soil profile in a grassland, forestland and shrubland on the Loess Plateau and determined the driving factors that affected their variations. Our results showed that SOCS and SWS varied across the 0–200 cm soil profile and considerably accumulated in the deep soil layers (100–200 cm). In comparison to SOCS, SWS generally had higher relative benefits in most studied plant communities, which ensured sustainable restoration. In addition, land use played a less important role than local environmental conditions in determining the variations in SOCS and SWS. Specifically, the interaction between SOCS and SWS was mainly strong in the surface soil layers (0–20 cm). Topography was a predominant factor that affected SOCS and SWS in the deep soil layers (100–200 cm), while soil texture was a stable driving factor influencing their variations across the whole soil profile (0–200 cm). Given the low moisture consumption of grasslands and the lowest root mean square deviation (RMSD) of Hippophae rhamnoides, we proposed an advanced scenario for ecological restoration on the Loess Plateau: establishing reasonably large Hippophae rhamnoides patches with fewer edges in a contiguous grassland matrix. Furthermore, this scenario should be tailored to local environmental conditions, such as soil water, texture and topography, followed by natural vegetation succession.
60. 题目: Modeling the formation of trihalomethanes in rural and semi-urban drinking water distribution networks of Costa Rica
期刊: Environmental Science and Pollution Research
作者: Daniel Enrique Kelly-Coto, Alejandra Gamboa-Jiménez, Diana Mora-Campos, Pablo Salas-Jiménez, Basilio Silva-Narváez, Joaquín Jiménez-Antillón, Macario Pino-Gómez, Luis Guillermo Romero-Esquivel
摘要: Chlorination is one of the most important stages in the treatment of drinking water due to its effectiveness in the inactivation of pathogenic organisms. However, the reaction between chlorine and natural organic matter (NOM) generates harmful disinfection by-products (DBPs), such as trihalomethanes (THMs). In this research, drinking water quality data was collected from the distribution networks of 19 rural and semi-urban systems that use water sources as springs, surfaces, and a mixture of both, in three provinces of Costa Rica from April 2018 to September 2019. Twelve models were developed from four data sets: all water sources, spring, surface, and a mixture of spring and surface waters. Linear, logarithmic, and exponential multivariate regression models were developed for each data set to predict the concentration of total trihalomethanes (TTHMs) in the distribution networks. Concentrations of TTHMs were found between < 0.20 and 91.31 µg/L, with chloroform being the dominant species accounting for 62% of TTHMs on average. Turbidity, free residual chlorine, total organic carbon (TOC), dissolved organic carbon (DOC), and ultraviolet absorbance at 254 nm (UV254) showed a significant correlation with TTHMs. In all the data sets the linear models presented the best goodness-of-fit and were moderately robust. Four models, the best of each data set, were validated with data from the same systems, and, according to the criteria of R2, standard error (SE), mean square error (MSE), and mean absolute error (MAE), spring water and mixed spring/surface water models showed a satisfactory level of explanation of the variability of the data. Moreover, the models seem to better predict TTHM concentrations below 30 µg/L. These models were satisfactory and could be useful for decision-making in drinking water supply systems.