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1. 题目: Biochar amendment affects the microbial genetic profile of the soil, its community structure and phospholipid fatty acid contents
文章编号: N24101215
期刊: Science of the Total Environment
作者: Mbezele Junior Yannick Ngaba, Bin Hu, Heinz Rennenberg
更新时间: 2024-10-12
摘要: Biochar (BC) amendment has been proposed as a promising strategy for mitigating greenhouse gas (GHG) emissions, specifically carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). Conducting a meta-analysis to evaluate the impact of biochar on microbial genetic profile, community structure, and phospholipid fatty acid (PLFA) contents can aid in identifying key microbial groups involved in GHG production and consumption, and assessing the overall effectiveness of biochar in reducing GHG emissions. The present meta-analysis revealed that the addition of biochar resulted in a 22 % and 41 % reduction in pmoA and mcrA genes of methanogenic microorganisms, respectively. The mcrA/pmoA ratio significantly increased by 81 %. Gene abundances exhibited a positive response to biochar amendment, with increases observed in nifH, nirK, nirS, nosZ, and nosZ (nirS + nirK) genes by 13 %, 32 %, 37 %, 42 %, and 79 %, respectively. Moreover, biochar amendment influenced the microbial community structure accordingly. The concentration of PLFAs increased in response to BC treatment in the following order: A-bacteria (+49 %) < Fungi (+30 %) < Gram-pb (+21 %) < G-bacteria (+17 %) < Gram-nb (+11 %). These findings indicate that biochar amendment shapes the microbial community structure, further emphasizing its significance in enhancing soil fertility.

2. 题目: A quantitative review of the effects of biochar application on the reduction of Cu concentration in plant: a meta-analysis
文章编号: N24101214
期刊: Environmental Science and Pollution Research
作者: Ningyu Guo, Xue Li, Linzhi Xie, Shangyan Hao, Xinbin Zhou
更新时间: 2024-10-12
摘要:

Contamination and toxicity of copper (Cu) in soils are global issues, particularly in regions where Cu-based fungicides are utilized. Elevated Cu concentrations can lead to soil contamination and pose significant risks to the ecosystem, including plant life, wildlife, and human health. The application of biochar has been proposed as a viable strategy to mitigate Cu accumulation in plants. However, there is no quantitative and data-based consensus on the impact of biochar on plant Cu accumulation. In this meta-analysis, 624 data records from 65 published literature were collected and the effects of various factors, including biochar properties, experimental conditions, and soil properties on Cu accumulation in plants, were examined through meta-subgroup analysis and meta-regression models. The results obtained indicate a significant dose-dependent effect of biochar in decreasing Cu concentration in plants by an average of 23.45%. Soils with acidic pH values and medium textures were more conducive for biochar to mitigate Cu accumulation in plant tissues. In addition, manure biochar and green waste biochar were found to be more successful in decreasing Cu concentrations in plants compared to other biochar types. Biochar types with pyrolysis temperatures of > 600 °C and pH values of ≥ 10 resulted in greater decreases in plant Cu concentration. Regarding biochar application, biochar minimum range of 1% in potting experiments and 20 t/ha in field experiments have been recommended to effectively decrease Cu concentration in plants. Overall, these findings provide valuable insights into Cu transfer mitigation through food chain to human bodies and for policymakers to take preventive measures.

Graphical abstract

3. 题目: Biochar supported modified nZVI for effective remediation of hexavalent chromium: Enhanced performance and remediation mechanism
文章编号: N24101213
期刊: Journal of Environmental Chemical Engineering
作者: Chuanyu Li, Ye Hu, Chao Yan, Yuqing Zhang, Yuxian Fan, Debin Ji, Baohui Wang, Lingyue Zhu
更新时间: 2024-10-12
摘要: In this study, a novel composite material, oxalic acid-modified nano zero-valent iron onto biochar (OA-nZVI/BC), was synthesized through a systematic mechanical ball milling process. Experimental results demonstrated that OA-nZVI/BC exhibited 8 times greater efficiency than nZVI in removing Cr (VI) at pH=6. The FeC₂O₄ shell enhanced electron transfer and facilitated the corrosion of iron nuclei to generate more Fe (Ⅱ), thereby aiding in the reduction of Cr (VI), as confirmed by electrochemical tests and 1,10-phen shielding experiments, among others. Remarkably, antioxidant experiments revealed that the FeC₂O₄ shell effectively inhibited the oxidation of nZVI. Following 30 days of oxidation, OA-nZVI/BC maintained a high removal efficiency of Cr (VI), reaching 83.23%. Importantly, the removal of Cr (VI) by OA-nZVI/BC was observed to be devoid of Cr (III) generation based on ionic detection. Through a series of experiments and characterization techniques, it was observed that biochar not only prevented nZVI agglomeration effectively but also utilized its surface hydroxyl groups to chelate Cr (III), significantly enhancing the capture and immobilization of Cr (VI) and demonstrating superior removal efficiency of Cr (VI). OA-nZVI/BC efficiently removes Cr (VI) across a broad pH range and in the presence of various anions. The removal of Cr (VI) by OA-nZVI/BC consistently exceeded 70% after five cycles of reuse. This study presents a sustainable strategy for Cr (VI) remediation and introduces an innovative material to environmental remediation, offering substantial scientific significance and practical applicability.

4. 题目: Microbial necromass and glycoproteins for determining soil carbon formation under arbuscular mycorrhiza symbiosis
文章编号: N24101212
期刊: Science of the Total Environment
作者: Jie Zhou, Nataliya Bilyera, Thomas Guillaume, Haishui Yang, Feng-Min Li, Lingling Shi
更新时间: 2024-10-12
摘要: Arbuscular mycorrhizal fungi (AMF) form symbioses with most terrestrial plants and critically modulate soil organic carbon (C) dynamics. Whether AMF promote soil C storage and stability is, however, largely unknown. Since microbial necromass C (MNC) and glomalin-related soil protein (GRSP) are stable microbial-derived C in soils, we therefore evaluated how AMF symbiosis alters both soil C pools and their contributions to soil organic C (SOC) under nitrogen fertilization, based on a 16-weeks mesocosm experiment using a mutant tomato with highly reduced AMF symbiosis. Results showed that SOC content was 4.5 % higher following AMF symbiosis. Additionally, the content of MNC and total GRSP were 47.5 % and 22.3 % higher under AMF symbiosis than at AMF absence, respectively. The accumulations of GRSP and microbial necromass in soil were closely associated with mineral-associated organic C and the abundance of AMF. The increased soil living microbial biomass under AMF symbiosis was mainly derived from AMF biomass, and fungal necromass C significantly contributed to SOC accumulation, as evidenced by the higher fungal:bacterial necromass C ratio under AMF symbiosis. On the contrary, bacterial necromass was degraded to compensate for the increased microbial nutrient demand because of the aggravated nutrient limitation under AMF symbiosis, leading to a decrease in bacterial necromass. Redundancy analysis showing that bacterial necromass is negatively correlated with soil C:N ratio supported this argument. Moreover, the relative change rate of total GRSP was consistently greater in nitrogen-limited soil than that of microbial necromass. Our findings suggested GRSP accumulates faster and contributes more to SOC pools under AMF symbiosis than microbial necromass. The positive correlation between the contributions of GRSP and MNC to SOC further provided valuable information in terms of enhancing our understanding of mechanisms underlying the maintenance of SOC stocks through microbial-derived C.

5. 题目: Fate of dissolved organic matter across the permafrost–nearshore water continuum: role of the intertidal sediments
文章编号: N24101211
期刊: Biogeosciences
作者: Aude Flamand, Jean-François Lapierre, Gwénaëlle Chaillou
更新时间: 2024-10-12
摘要: . Increasing rates of coastal erosion and permafrost thaw along the Arctic coastline represent a major lateral source of dissolved organic matter (DOM) to the coastal environment, where it can meet multiple fates depending on its origin and composition. Along the (ground)water flow path, Iron (Fe)-hydroxides play an important role in the retention of terrestrial organic matter, but its role on DOM released from coastal thawing permafrost specifically remains poorly understood. To address this gap, we sampled permafrost meltwater, beach groundwater, and seawater samples from several coastal bluffs transects up to 2 km from the shoreline. Across the salinity gradient – from permafrost meltwater to nearshore waters - we found that dissolved organic carbon (DOC) and chromophoric dissolved organic matter (CDOM) concentrations decreased drastically, indicating significant removal processes along this continuum. Optical indices (aCDOM350, SUVA254, HIX) reflected changes in DOM composition and aromaticity, suggesting microbial degradation and mineral-organic interactions occur to transform DOM. Furthermore, a PARAFAC analysis of fluorescent DOM indicated that permafrost-derived DOM had a high molecular weight (HMW), humic, and terrigenous origin, while coastal ocean-derived FDOM was protein-rich, low molecular weight (LMW), and from microbial (autochthonous) origin. The optical signature of permafrost meltwater faded along the permafrost-nearshore water continuum. Controlled experiments with excess Fe²⁺ along constant oxygen bubbling showed a rapid (within 6 hours) and major decrease in DOC and CDOM, suggesting interaction with reactive Fe-hydroxides, acting as a permanent or temporary trap of permafrost-derived DOM. Overall, our findings highlight the role of intertidal and nearshore zones where subsurface flows regulate the persistence and reactivity of terrestrial DOM as it transits from permafrost to marine environments in the Arctic.

6. 题目: Sustainable Enhancement of Biogas Production from a Cold-Region Municipal Wastewater Anaerobic Digestion Process Using Optimized Sludge-derived and Commercial Biochar Additives
文章编号: N24101210
期刊: Journal of Cleaner Production
作者: Rahman Zeynali, Mohsen Asadi, Phillip Ankley, Milena Esser, Markus Brinkmann, Jafar Soltan, Kerry McPhedran
更新时间: 2024-10-12
摘要: Anaerobic digestion (AD) of municipal wastewater sludges produces valuable solid digestate and biogas. Biogas is a source of clean energy and enhancement of its production has been of recent interest for increased electricity generation, among other products. The objective of this study was the development of a novel municipal sludge-derived biochar and its application in a municipal wastewater AD system to increase the biogas production rate. Thickened waste-activated sludge (TWAS) samples were collected from the cold-region municipal wastewater treatment plant and used to synthesize biochar applied in the simulation of AD processes using laboratory-scale reactors. The TWAS-derived biochar was synthesized using the commonly used furnace pyrolysis (sludge-based biochar, SBC), and more novel microwave pyrolysis including phosphoric acid as a microwave activator (activated sludge-based biochar, ASBC). The microwave pyrolysis conditions were optimized using a computational fluid dynamics (CFD) technique. In addition, various commercially available carbon-based additives were assessed for their impacts on the AD process including activated carbon, wood-derived biochar, and forest residue-derived biochar. Results showed that the ASBC increased the cumulative methane production by 50% (333 mL/g VS) versus the control sample (221 mL/g VS) after 30 d. The ASBC showed higher surface area, electrical conductivity, and metal contents versus the other biochars which boosted the AD microbial community growth leading to higher organic matter conversion into biogas. In the ASBC-amended digesters, the bacterial phylum Bacteroidota, which contains a major genus of the dgA-11-gut-group, exhibited a synergy between organic substrate fermentation and volatile fatty acid production, resulting in enhanced biogas production. The TWAS biochar demonstrated promising performance in enhancing the AD process fostering energy and resource self-sufficiency at municipal wastewater treatment plants. This smart sludge management aligns well with sustainable waste management practices and clean energy production strategies, especially considering that the biochar was sourced from a readily available continuous waste-product stream.

7. 题目: Exploring the Impact of Biochar‐Dolomite Application at Different Pyrolysis Temperatures on Acid Sulfate Soil Properties
文章编号: N24101209
期刊: Land Degradation & Development
作者: Syazwan Sulaiman, Namasivayam Navaranjan, Guillermo Hernandez‐Ramirez, Zohrah Sulaiman, Kathereen Liew
更新时间: 2024-10-12
摘要: The use of biochar as a soil amendment for acid soil, particularly acid sulfate soil, has garnered significant interest due to its capacity to improve soil properties, which is further accentuated when combined with dolomite. However, the extent to which the magnitude and direction of this effect vary with biochar produced at different pyrolysis temperatures remains uncertain. We conducted an incubation by mixing soil with dolomite and biochar types derived from Melastoma malabathricum (MMBC) and Dicranopteris linearis (DLBC) at three temperatures (300, 500, and 700°C). The incorporation of dolomite with both biochar types led to significant improvements in soil pH, available P, available Fe, exchangeable K, and exchangeable Ca compared to soil amended with dolomite only. These enhancements were likely attributed to the release of alkalinity, which further raised soil pH, as well as the direct dissolution of P, K, and Ca from the biochar. Moreover, the reduced Fe availability was likely due to the complexation of Fe onto surface functional groups of biochar. Furthermore, these improvements surpassed the effect of the initial feedstock and became increasingly pronounced with higher pyrolysis temperatures. However, an antagonistic effect of dolomite and biochar co‐incorporation was observed, particularly in the relative reduction of soil exchangeable Mg with both biochar types, and a decrease in the soil available N with MMBC produced at 300 and 500°C compared to dolomite addition alone, which could be due to the adsorption of Mg and N onto biochar surface. The results indicate that concurrent application of dolomite and biochar can change the acid sulfate soil properties to varying magnitudes and in different directions, largely regulated by the characteristics of biochar as well as the probable interplay with dolomite. Consequently, selecting the appropriate biochar that aligns with the desired soil properties is crucial in managing dolomite‐treated acid sulfate soil.

8. 题目: Online monitoring of greywater reuse system using excitation-emission matrix (EEM) and K-PARAFACs
文章编号: N24101208
期刊: Water Research
作者: Yongmin Hu, Eberhard Morgenroth, Céline Jacquin
更新时间: 2024-10-12
摘要: A currently increasing interest in water reuse is met with the concern about water quality. Excitation-emission matrix (EEM) measurements, which are widely implemented in laboratory analysis, emerge as a promising tool for characterizing both microbial and chemical water qualities in the online monitoring of water reuse systems. However, the robustness of EEM measurements has been rarely validated in actual online monitoring campaigns where predictions are made for new samples independent of those used to establish EEM analysis models, including the popular parallel factor analysis (PARAFAC). In this study, two strategies of conducting PARAFAC were examined for the online monitoring of a greywater reuse system using two EEM datasets from two monitoring periods for model establishment and model testing respectively. With the first strategy that is commonly used in laboratory analyses, an entire EEM datasets from one period was used to establish one PARAFAC model, and the maximum fluorescence intensity (F_max) of a PARAFAC component was used to predict total cell count (TCC) in another period. However, under the disturbance of dissolved organic matter (DOM) fluorescence in the background, F_max gave unreliable predictions in model testing. To address this problem, a second and novel strategy was proposed using an EEM clustering and PARAFAC component shift mining technique. This unsupervised algorithm, named K-PARAFACs, automatically groups EEMs into K clusters and on each cluster establishes a cluster-specific PARAFAC model with distinct component shapes. With this method, multiple PARAFAC models were established on one EEM dataset, with each model representing samples with certain TCC ranges and DOM compositions. In model testing, these cluster-specific PARAFAC models served as EEM classifiers. A new sample was not characterized by F_max but by the cluster-specific model that best fitted the EEM signal of the sample with the least numerical error. The proposed strategy demonstrates its robustness by successfully predicting the TCC trend in test datasets. Our findings suggest that K-PARAFACs is a promising tool that enables robust qualitative monitoring of water reuse systems with background DOM variability.

9. 题目: Long-Term Photochemical and Microbial Alterations Lead to the Compositional Convergence of Algal and Terrestrial Dissolved Organic Matter
文章编号: N24101207
期刊: Environmental Science & Technology
作者: ShiLin An, YingXun Du, XiuLin Huang, YueHan Lu, ZhenDu Mao, LiMei Shi, James B Cotner, Peng Xing, YunLin Zhang
更新时间: 2024-10-12
摘要: Lakes are expected to become more active in processing dissolved organic matter (DOM), but the fate of DOM with different origins remains poorly constrained. We conducted long-term incubation experiments (∼1 year) with sole light, sole microbial, and combined light and microbial treatments using DOM from algal and terrestrial sources (DOMa and DOMt, respectively). Fourier transform ion cyclotron resonance mass spectrometry and 16s rRNA were used to analyze the DOM molecular composition and bacterial community, respectively. We observed that DOMa and DOMt converged toward a similar composition under the combined light and microbial treatment, driven by the removal of source-specific compositions along with the production of refractory, carboxylic-rich alicyclic molecules (CRAM). For CRAM enrichment, microbial processes played a greater role for DOMa, while phototransformation was more important for DOMt. The co-occurrence patterns between DOM molecules and bacteria showed that DOM molecular composition influenced the bacterial community. More complex DOM-bacteria interactions were observed for DOMt compared to DOMa, suggesting that greater bacterial cooperation was necessary for transforming DOMt. Collectively, these findings offer new insights into the mechanisms underlying the uniformity of DOM from various sources through prolonged environmental transformations in lakes.

10. 题目: Foraging tunnel disturbances created by small subterranean herbivores enhance soil organic carbon stability but reduce carbon sequestration in different alpine grassland types
文章编号: N24101206
期刊: Science of the Total Environment
作者: Huan Yang, Duan Yuan Yuan, Zheng Gang Guo, Xiao Pan Pang
更新时间: 2024-10-12
摘要: Foraging tunnel disturbances by small subterranean herbivores can alter soil properties and nutrient dynamics in grasslands, potentially altering soil organic carbon (SOC). Examining the impact of foraging tunnel disturbances on mineral-associated organic carbon (MAOC) and particulate organic carbon (POC) is crucial for understanding SOC changes and its stability. However, the effects of these disturbances on POC and MAOC are not well documented. This study uses the plateau zokor (Eospalax baileyi) as a focal subterranean herbivore to investigate the effects of foraging tunnel disturbances on POC and MAOC in alpine steppes, alpine meadows, and alpine meadow steppes. Ninety paired quadrats were used for soil and plant sampling across three alpine grassland types. Results show that foraging tunnel disturbances consistently reduced POC concentrations across all grassland types, with reductions of 44.01 % in alpine steppes, 20.86 % in alpine meadows, and 29.58 % in alpine meadow steppes. MAOC concentrations decreased by 16.49 % in alpine steppes, while no significant changes in MAOC were observed in alpine meadows and alpine meadow steppes. The reduction in the POC to MAOC ratio indicates increased SOC stability. However, despite this increased stability, the change may lead to a decrease in overall carbon sequestration potential, as the total SOC in the soil declines. The main factors influencing POC and MAOC were soil moisture, belowground biomass, and microbial biomass carbon, with their influences varying by grassland type. The findings demonstrate that foraging tunnel disturbances by plateau zokors can lead to substantial modifications in SOC composition, influencing both its stability and sequestration potential. The disturbances necessitate tailored management strategies to mitigate their impacts, considering the unique characteristics of each grassland type to preserve carbon sequestration potential. This study contributes to a deeper understanding of the ecological role of small subterranean herbivores in the carbon cycle of alpine grassland ecosystems.

11. 题目: Microplastics impair extracellular enzymatic activities and organic matter cycling in oligotrophic sandy marine sediments
文章编号: N24101205
期刊: Science of the Total Environment
作者: Alessandro Cau, Davide Moccia, Claudia Dessì, Laura Carugati, Ester Carreras-Colom, Fabrizio Atzori, Nicoletta Cadoni, Antonio Pusceddu
更新时间: 2024-10-12
摘要: Microplastics (MPs) are ubiquitous and constantly accumulating in the marine environment, especially sediments. Yet, it is not well clarified if and how their carbon backbone could interact with surrounding sediments, eventually impairing key benthic processes. We assessed the effects of a ‘pulse’ contamination event of MPs on sedimentary organic matter (OM) quantity, quality and extracellular enzymatic activities (EEAs), which are well established descriptors of benthic ecosystem functioning. Marine sediments were exposed for 30 days to environmentally relevant concentrations (~0.2 % in weight) of naturally weathered particles (size range 70–210 μm) of polyurethane, polyethylene, and a mixture of the most common polymers that are documented to accumulate in marine sediments. Despite the low concentration, contaminated sediments showed significantly different composition of OM, showing a decrease in lipid content and increase in protein. Moreover, we document a significant decrease (over 25 %) in quantity of biopolymeric C already after 15 days of exposure, compared to controls. Contaminated sediments showed lower C degradation rates (up to −40 %) and altered EEAs, with alkaline phosphatase being ~50 % enhanced and aminopeptidase being reduced over 35 % compared to control treatments. Overall, the effects generated by the mixture of polymers were smaller than those exerted by the same amount of a single polymer. Our results provide insights on how that MPs can significantly alter marine sedimentary biogeochemistry through altered benthic processes, that could cumulatively impair whole benthic trophic webs by enhancing the accumulation and possible longer-term storage of recalcitrant organic C in the seabed.

12. 题目: Increased rainfall frequency enhances dry seasonal soil mineral-associated organic carbon in a subtropical forest
文章编号: N24101204
期刊: Science of the Total Environment
作者: Jingwen Chen, Xiaomei Chen, Qiong Chen, Yiren Zhu, Qi Deng
更新时间: 2024-10-12
摘要: Climate models predict longer and more severe droughts, and alterations in the frequency and intensity of rainfall events. However, how changing precipitation patterns affect soil organic carbon (SOC), particulate organic carbon (POC), and mineral-associated organic carbon (MAOC) remains unclear. Here, we conducted a three-year rainfall manipulation experiment with ambient rainfall as the control, removal of half the total rainfall amount with unaltered frequency (DRA), and increased rainfall frequency with the total amounts unchanged (IRF) in a subtropical forest. The results showed that the rainfall treatments did not change SOC content or fractions during the wet season. In the dry season, DRA significantly increased topsoil POC but did not change SOC or MAOC. IRF significantly increased POC and MAOC levels. The increased MAOC was associated with the newly formed binary complexes of Fe³⁺, Al³⁺, and Ca²⁺, and the adsorption/precipitation of reduced short-range-ordered Fe oxides, likely derived from the enhanced reductive dissolution in the IRF treatment. Our results suggest that changes in rainfall frequency affect organo-mineral interactions more profoundly relative to the rainfall amount and that these effects are season-dependent. Therefore, moisture-sensitive geochemical processes play an essential role in SOC stabilization in subtropical forests.

13. 题目: Application of straw-derived biochar: a sustainable approach to improve soil quality and crop yield and reduce N2O emissions in paddy soil
文章编号: N24101203
期刊: Environmental Science and Pollution Research
作者: Raushan Kumar, Bipradeep Mondal, Nirmali Bordoloi
更新时间: 2024-10-12
摘要:

The burning of agricultural straw is a pressing environmental issue, and identifying effective strategies for the rational utilization of straw resources is decisive for achieving sustainable development. Owing to its high carbon content and exceptional stability, straw biochar produced via pyrolysis has emerged as a key focus in multidisciplinary research. However, the efficacy of biochar in mitigating nitrous oxide (N₂O) emissions from paddy soils is not consistent. A 2-year field experiment was conducted and investigated the impact of biochar derived from two feedstocks (rice straw and wheat straw, pyrolyzed at 450 °C) on N₂O emissions, global warming potential (GWP), greenhouse gas intensity (GHGI), nitrogen use efficiency (NUE), crop yield, and soil quality. The static chamber technique was used for collecting N₂O gas samples, and concentrations were analyzed through gas chromatography methods. The treatment combinations included BR0 (control), BR1 (NPK at the recommended dose, 120:60:40 kg ha⁻¹), BR2 (wheat straw biochar, 5 t ha⁻¹), and BR3 (rice straw biochar, 5 t ha⁻¹). The results exhibited that cumulative N₂O emissions from BR2 and BR3 treatments decreased by 10.55% and 13.75% respectively, compared to BR1. Lower GWP and GHGI were observed under both biochar treatments compared with BR1. The highest rice grain yield (3.48 Mg ha⁻¹) and NUE (76.72%) were recorded from BR3, which also exhibited the lowest yield-scaled N₂O emission. We observed positive correlations between soil nitrate, ammonia and water-filled pore spaces, while NUE showed negative correlations with N₂O emissions. Significant (p < 0.05) improvements in soil quality were also detected in both the biochar treated plots, indicated by increased soil pH, water holding capacity, porosity, and nutrient contents. Overall, the results suggest that applying biochar at a rate of 5 t ha⁻¹ in paddy soil is a viable nutrient management strategy with the potential to reduce reliance on inorganic fertilizers, mitigate N₂O emissions, and contribute to sustainable food production.

14. 题目: Organic carbon compounds removal and phosphate immobilization for internal pollution control: Sediment microbial fuel cells, a prospect technology
文章编号: N24101202
期刊: Environmental Pollution
作者: Zhenzhen Hu, Qinqin He, Hongjun Zhao, Lingjun Wang, Yuxin Cheng, Xiaonan Ji, Yali Guo, Wei Hu, Min Li
更新时间: 2024-10-12
摘要: As a current technology that can effectively remove organic carbon compounds and immobilize phosphorus in sediment, sediment microbial fuel cells (SMFCs) can combine sediment remediation with power generation. This review discusses the removal efficiency of SMFCs on organic carbon compounds, including sediment organic matter, antibiotics, oil-contaminated sediments, methane, persistent organic pollutants, and other organic pollutants in sediment, with more comprehensive and targeted summaries, and it also emphasizes the mitigation of phosphorus pollution in water from the perspective of controlling endogenous phosphorus. In this review, the microbial community is used as a starting point to explore more about its roles on phosphorus and organic carbon compounds under SMFCs. Electrode modification, addition of exogenous substances and combinations with other technologies to improve the performance of SMFCs are also reviewed. It is further demonstrated that SMFCs have the prospect of long-term sustainability, but more attention needs to be paid to the study of the mechanism of SMFCs and the continuous improvement of devices for further application in practice.

15. 题目: Biochar captures ammonium and nitrate in easily extractable and strongly retained form without stimulating greenhouse gas emissions during composting
文章编号: N24101201
期刊: Journal of Environmental Quality
作者: Franziska Busch, Otávio dos Anjos Leal, Nina Siebers, Nicolas Brüggemann
更新时间: 2024-10-12
摘要: During composting of organic waste, nitrogen is lost through gaseous forms and ion leaching. Biochar has been shown to capture mineral nitrogen (Nmin: NH4+ and NO3−) from compost, which we hypothesize reduces N2O formation. However, associating Nmin captured by biochar with the dynamics of N2O and other greenhouse gas (GHG) emissions during composting remains unstudied and was the aim of this work. We composted (outdoor for 148 days) together kitchen scraps (43.3% dw, where dw is dry weight), horse manure (40.9% dw), and wheat (Triticum aestivum L) straw (15.8% dw) without (Control) or with biochar (Bc, 15% compost dw). The biochar consisted of hardwood and softwood pieces pyrolyzed at 680°C and exhibited 60% of particles with 4–8 mm. We monitored compost GHG (CO2, CH4, N2O) emissions, Nmin content in compost and biochar particles (sequential extractions), and biochar surface transformations (SEM‐EDX and 13C‐NMR spectroscopy) along composting. Biochar did not significantly reduce or increase GHG emissions and Nmin content (mg kg−1) in compost. However, the final NO3− amount (g compost pile−1) in the Bc treatment was significantly higher (54%) compared to the Control, indicating lower NO3− losses. Despite the high aromaticity and minimal contribution of carboxyl C to the biochar structure, biochar retained NH4+, mainly in easily extractable form (55%), in the first 2 weeks of composting and mainly in strongly retained form (75%) in the final compost. The NO3− content in biochar increased continuously during composting. In the final compost, the NO3− content extracted from biochar was 164 (37%, easily extractable), 80 (19%, moderately extractable), and 194 mg NO3−–N kg−1 (44%, strongly retained). Although Nmin retention in biochar was not accompanied by lower N2O emissions, contradicting our hypothesis, we demonstrated the efficacy of biochar to recover Nmin from organic waste without stimulating GHG emissions.

16. 题目: Synchronous sequestration of inorganic and organic phosphorus from eutrophic surface water and sediments via recoverable La-CaO2@HNTs/SA hydrogel beads
文章编号: N24101121
期刊: Chemical Engineering Journal
作者: Chongming Wang, Sujie Shan, Zhengyu Yang, Xinpeng Xu, Xingning Huang, Xi Li, Songqi Liu, Boling Li, Yao Xu, Dapeng Li
更新时间: 2024-10-11
摘要: Mounting evidence indicates that eliminating phosphate (P_i) alone is not enough to lower outbreak risks of undesirable algae, and synchronously sequestrating organic phosphorus species (OPs) dissolved in overlying water and residing in sediments cannot be ignored. However, more efforts were focused on the immobilization of P_i than OPs because of insufficient understanding and analytical challenges. Herein, CaO₂-loaded halloysite nanotubes/lanthanum-crosslinked sodium alginate (La-CaO₂@HNTs/SA) hydrogel beads were newly developed and employed as a capping material for efficiently sequestrating P_i and OPs from eutrophic water and sediment. Batch sorption results showed that the La-CaO₂@HNTs/SA has a high uptake capacity towards P_i (i.e., 44.05 mg-P/g) and Myo-inositol hexakisphosphate (IHP, a representative pollutant of OPs, 36.28 mg-P/g), and good selectivity for P in the presence of NO₃^–, Cl⁻, and HCO₃^–, profited by synergy of electrostatic attraction, inner-sphere complexation, surface precipitation, and partial degradation. After applying La-CaO₂@HNTs/SA, P levels in overlying water could rapidly reduce from 0.95 to 0.01 mg-P/L within 120 min. Further thin-layer capping experiments (60 days) indicated that La-CaO₂@HNTs/SA performed very well in immobilizing P_i and OPs in overlying and pore waters and enhancing reductant-soluble P transformation (BD-P; ∼19 % to 11 %) to more stable HCl-extracted P (HCl-P; ∼33 % to 43 %) in sediments under continuous P input with minor effect on benthic microorganisms. These findings advance the use of eco-friendly La-CaO₂@HNTs/SA in eutrophication alleviation via simultaneous sequestration of P_i and OPs.

17. 题目: Online in-situ modification of biochar for the efficient immobilization of elemental mercury and co-benefit of SO2/NO removal
文章编号: N24101120
期刊: Chemical Engineering Journal
作者: Qiqi Yao, Ziyao Yang, Cong Nie, Mantang Chen, Xuehui Sun, Jiaxin Zhu, Yang Xu
更新时间: 2024-10-11
摘要: In this study, non-thermal plasma discharge was proposed for online in-situ modification of biochar injected into coal-biomass co-combustion flue gas, aiming to achieve the combined removal of elemental mercury (Hg⁰), NO, and SO₂ from flue gas. After plasma discharge, the pore structure of biochar was slightly improved whereas the surface morphology of biochar was almost unchanged. After plasma discharge under O₂, SO₂, and HCl atmospheres, the oxygen, sulfur, and chlorine contents of biochar were obviously increased. More exactly, additional functional groups were formed on the modified biochar surface, such as CO, C(O)OC, CS, and CCl. Compared with raw biochar, the biochar modified under HCl, SO₂, O₂, H₂O and CO₂ atmospheres exhibited higher Hg⁰ removal efficiency, and longer modification time resulted in better Hg⁰ removal performance. The optimal modification atmosphere and reaction temperature were the simulated flue gas (SO₂ + HCl + CO₂ + O₂ + H₂O + NO + N₂) and 20 ℃-100 ℃, respectively. The modified biochar exhibited excellent resistance to SO₂ and H₂O. The addition of HCl, CO₂, NO, and O₂ contributed to Hg⁰ removal. The removal efficiency of NO and SO₂ attained a maximum of 100 %. The Hg⁰ removal mechanism was further revealed, where CO, C(O)OC, CS, and CCl served as active components.

18. 题目: Biochar affects organic carbon composition and stability in highly acidic tea plantation soil.
文章编号: N24101119
期刊: Journal of Environmental Management
作者: Qiang Li, Junchuan Zhang, Jing Ye, Yue Liu, Yi Lin, Zhigang Yi, Yixiang Wang
更新时间: 2024-10-11
摘要: Biochar amendments are effective in stabilizing soil aggregates and improving soil organic carbon (SOC) content. However, the effects of biochar on highly acidic soil and their relation with soil SOC stability remain understudied. The study aimed to investigate the impact of biochar on changes of aggregate distribution and SOC stability in a highly acidic tea plantation soils over an eight-year period. Soil samples were collected from plots with varying biochar application amounts (0, 2.5 t ha-1, 5 t ha-1, 10 t ha-1, 20 t ha-1 and 40 t ha-1). The content of SOC, iron bound organic carbon (OC-Fe), particulate organic carbon (POC), mineral-associated organic carbon (MAOC) and the functional group composition of SOC was analyzed. The results indicated that in the biochar application treatments, the value of soil pH, SOC, POC and MAOC contents were increased from 3.92 to 4.28, 6.68%-187.02%, 8.31%-66.78% and 13.07%-236.47% respectively, compared with CK, while the content of macro-aggregate (particle size>0.25 mm) and soil aggregates mean weight diameter (MWD) significantly increased with higher biochar application amounts. But dissolved organic carbon (DOC) and OC-Fe content exhibited downward trend, decreased from 2.43% to 6.97% and 4.18%-19.91%. Furthermore, aromatic-C levels increased, with increased biochar application amounts. The integration of biochar not only bolstered soil aggregate stability but also amplified the presence of aromatic-C, thereby enhancing the resilience of organic carbon in highly acidic tea garden soil (BC40 > BC20 > BC5>BC2.5 > BC10 > CK), with increases ranging from 6% to 47%. The principal component analysis and structural equation modeling identified soil pH, TN, SOC, POC, MAOC, R > 0.25 and MWD as key factors of soil organic carbon stability. These findings provide crucial insights into the mechanism underlying biochar's efficiency in fortifying organic carbon stability, particularly in the context of highly acidic soil.

19. 题目: Unlocking the solution-phase molecular transformation of biochar during intensive rainfall events: Implications for the long-term carbon cycle under climate change
文章编号: N24101118
期刊: Science of the Total Environment
作者: Yuqing Sun, Zibo Xu, Mingjing He, Daniel S Alessi, Daniel C W Tsang
更新时间: 2024-10-11
摘要: The unclear turnover of soluble and solid phases of biochar during increasingly severe climate change (e.g., intensive rainfall) raised questions about the carbon stability of biochar in soil. Here, we present an in-depth analysis of the molecular-level transformations occurring in both the soluble and solid phases of biochar subjected to prolonged wet-dry cycles with simulated rainwater. Biochar properties, including surface functionality and carbon texture, greatly affected the transformation route and led to a distinct stability variation. The rich alkyl −CH₃ on the low-temperature biochar (450 °C) was oxidized to hydroxymethyl −CH₂OH or formyl −CHO, and the ester −COOC− or peptide −CONHC− bonds were fragmented in the meantime, causing the release of protein- or lipid-like organic carbon and the declined carbon stability (Æ, tested by H₂O₂ oxidation, from 60.1 % to 53.2 %). After a high-temperature (750 °C) pyrolysis process, only oxidation of the surface −OH with limited bond breaking occurred after rainwater elution, presenting a marginal composition difference with constant stability. However, the fragile carbon nature of biochar, caused by CO₂ activation, led to enhanced fragmentation, oxidation, and hydration, resulting in the release of tannin-like organic carbon, which compromises the carbon storage (Æ decreased from 81.2 % to 73.0 %). Our findings evaluated the critical transformation of biochar during intensive rainfall, offering crucial insights for designing sustainable biochar and achieving carbon neutrality.

20. 题目: Comparing photoactivities of dissolved organic matter released from rice straw return under varying alkali concentration: Insights from molecular structure and photoactive species
文章编号: N24101117
期刊: Chemical Engineering Journal
作者: Tong Cai, Yuanbo Ming, Xiaotong Zhang, Xilong Zheng, Lichun Shen, Xuan Lyu, Qiuzhuo Zhang
更新时间: 2024-10-11
摘要: Alkali treatment can prevent soil acidification caused by rice straw returning to the field. However, the photochemical behavior of dissolved organic matter (DOM) released from rice straw after alkali addition and its underlying mechanism remain unclear. This study investigated the molecular composition and photochemically produced reactive intermediates (PPRIs) of DOM from rice straw extracted using water (CRDOM) and extracted from rice straw with varying alkali concentration (ARDOM). The experimental results indicate that alkali additive facilitates DOM release, ranging from 384.2 to 2054.4 mg C/L. Fourier transform ion cyclotron resonance mass spectrometry revealed the dominance of unsaturated and phenolic compounds in both CRDOM (63.6 %) and ARDOM (ranging from 55.8 % to 57.7 %). Under simulated solar irradiation, ARDOM-Low exhibited the highest apparent quantum yields (AQYs) for ³DOM* (54.13), ¹O₂ (1.52 × 10^-2) and ^•OH (4.46 × 10^-5). This phenomenon maybe attributed to the lower molecular weight and higher unsaturated compounds of ARDOM-Low. Additionally, as a representative pollutant in modern ecological agriculture park, sulfadimidine (SM2) was chosen to be investigated for its photodegradation by DOM. The results suggested that ARDOM-Low effectively facilitated the photodegradation of SM2, with ³DOM* as the main photoreactive species, providing evidence for higher AQYs of PPRIs facilitated by ARDOM-Low. This study provides new insights into understanding the molecular composition and photochemical processes of DOM released during rice straw return, thereby offering theoretical guidance for rice straw return practices in agriculture.