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261. 题目: The construction of magnetic hydroxyapatite-functionalized pig manure-derived biochar for the efficient uranium separation
文章编号: N23010710
期刊: Chemical Engineering Journal
作者: Jun Liao, Xiaoshan He, Yong Zhang, Lin Zhang, Zhibing He
更新时间: 2023-01-07
摘要:

In this work, three magnetic biochar-supported nano-hydroxyapatite materials were prepared by endowing different magnetic sources, which showed excellent reusability and adsorption ability. It was worth mentioning that the maximum adsorption capacity of the magnetic biochar-hydroxyapatite composite with nickel chloride as the magnetic source reached 1723.5 mg/g and the residual concentration of uranium in the solution could reach the limit standard of China for the discharge of uranium-containing wastewater at low uranium concentration. The removal efficiencies of the composite for uranium in different water systems were all higher than 90.2%, which reflected the applicability of the composite. Besides, the material was easy to be recycled and reused due to the magnetization. After eight times of reuse, the uranium removal efficiency was still higher than 96.3% and the magnetism was not significantly weakened. The multiple strong chemical reactions of active sites with uranium, including ion exchange, surface complexation and ionization-precipitation, were the major reason for the excellent adsorption ability. In conclusion, the magnetization of biochar-based materials might be a promising uranium adsorbent, which would open a new direction for the design of biochar-based adsorbents for uranium removal.

262. 题目: Modeling ecosystem-scale carbon dynamics in soil: The microbial dimension
文章编号: N23010709
期刊: Soil Biology and Biochemistry
作者: Joshua Schimel
更新时间: 2023-01-07
摘要:

In predicting how soil C fluxes and stocks will change with the environment, models are a critical tool for integrating datasets with theory. Models developed in the 1980's were based on 1st order kinetics of C-pools defined by turnover time. However, new models generally include microbes as decomposers although they vary in the number and nature of microbial pools. They don't, however, integrate modern omics-based datasets because models have coarse resolution and need to function even in the absence of community data—geographically or into the future. There are several issues new models must address to be valuable for large-scale synthesis. First, how to incorporate microbes and their activities—how many pools of organisms How should they be defined How should they drive C-cycling Should their synthesis of degradative enzymes be treated implicitly or explicitly Second, carbon use efficiency (CUE)—the partitioning of processed C between respiration and re-synthesis into biomass. This term is critical because the size of the biomass influences its rate of organic matter processing. A focus has been on CUE's temperature sensitivity—most studies suggest it declines as temperature rises, which would limit decomposition and organic matter loss. The final novel modeling element I discuss is “priming”—the effect of fresh inputs on decomposition of native organic matter (OM). Priming can either repress or accelerate the breakdown of native OM. But whether, and how, to capture priming effects in soil organic matter models remains an area of exploration.

263. 题目: Molecular transformation and bioavailability of dissolved organic nitrogen in sewage sludge under hydrothermal treatment
文章编号: N23010708
期刊: Chemical Engineering Journal
作者: Yu Zhang, Siying Cai, Hao Yuan, Boyuan Yang, Zexu Chen, Aibin Hu, Jing Ai, Dongsheng Wang, Weijun Zhang
更新时间: 2023-01-07
摘要:

Hydrothermal (HT) treatment has been considered effectively to recover nitrogen-containing organic nutrients from wastewater activated sludge (WAS), and understanding the fate and distribution of dissolved organic nitrogen (DON) during HT process is of great importance to process optimization. Thus, this study aims to investigate molecular transformation pathway of DON during HT process using non-targeted mass difference network analysis and evaluate the bioavailability of DON with chlorella. Results suggested that HT treatment was superior in N-containing organic matter solubilization (DON /TN > 60%), and DON in WAS underwent extensive transformation processes at various HT temperatures. From room temperature to 70 °C, nucleic acids were solubilized to HT liquor, accomplishing with deamidation (-CONH+H2/H2O). And a representative ribose nucleic acid with a ‘PA–pentose (ribose)–uracil (U)’ structure was identified. With temperature rising to 120 °C, large amounts of stable protein were solubilized and hydrolyzed into HT liquor. The non-targeted mass difference network analysis suggested that, from 160 °C to 200 °C, aspartyl, serine, histidine, and glutamyl units were representative precursors for a variety of reactions including Maillard reactions, deamidation, deamination and so on. Amino acids were deaminated (-NH) to produce organic acids and ammonia (ammonium) or decarboxylated (-COO) to produce amines and CO2. Dicarbonyl compounds (-C2H2O2) were identified as the most abundant fragments which could either form humic substances or Maillard reaction products. Chlorella growth bioassay indicated that org-N in HT liquor produced at 120 °C showed the highest bioavailability for Chlorella, while that generated in HT liquor above 160 °C inhibited the growth of Chlorella. This study provided molecular insights for DON transformation following HT process and promoted high-quality resource utilization of WAS.

264. 题目: Soil aggregate microstructure and microbial community structure mediate soil organic carbon accumulation: Evidence from one-year field experiment
文章编号: N23010707
期刊: Geoderma
作者: Weijun Zhang, Lars J Munkholm, Xu Liu, Tingting An, Yingde Xu, Zhuang Ge, Ninghui Xie, Aimeng Li, Yuqi Dong, Chang Peng, Shuangyi Li, Jingkuan Wang
更新时间: 2023-01-07
摘要:

Soil organic carbon (SOC) accumulation is easily susceptible to tillage managements, which strongly affect soil structure and microbial community structure. Subsoiling is developed for mitigating soil compaction and thus improving soil structure. Coupled with straw residue incorporation, it is expected not only to enhance this improvement but also to promote organic carbon (C) storage in soil. However, how subsoiling tillage managements change soil aggregate microstructure, microbial community structure and SOC fractions, and how soil aggregate microstructure and microbial community structure affect SOC in the topsoil and subsoil layers are equally unknown. An in-situ incubation field experiment was conducted in a Mollisol in northeastern China and included conventional tillage (CT), subsoiling tillage (ST) and subsoiling tillage with straw residue incorporation (ST + S). The methods of synchrotron-based X-ray micro-computed tomography scanning, phospholipid fatty acid and SOC density fractionation were used to analyze aggregate pore characteristics, microbial community structure and SOC fractions, respectively. The results showed that both ST and especially ST + S not only improved soil aggregate microstructure but also enhanced microbial biomass and then favored SOC accrual in the topsoil (0–20 cm). In the subsoil (20–35 cm), ST + S exerted similar positive effects as those in the topsoil. However, ST only improved soil aggregate microstructure but decreased microbial community biomass and SOC in the subsoil. Moreover, soil aggregate structure characteristics explained (solely explained 6 % in the topsoil and 12 % in the subsoil, respectively) a smaller part of the variation in SOC within aggregates than soil microbial characteristics did (solely explained 15 % in the topsoil and 25 % in the subsoil, respectively). Specifically, bacteria explained 26 % and 66 % of the variation in SOC within aggregates in the topsoil and subsoil, respectively. The porosity of macropores (>100 μm) also explained 25 % of the variation in SOC within aggregates in the topsoil, whereas the porosity of micropores (<30 μm) explained more variation (12 %) than that of macropores (3 %) in the subsoil. Notably, the substantially different interaction mechanism-processed of pore characteristics, microbial structure and SOC between topsoil and subsoil was probably traceable for the variation in the influx of organic C, pore size distribution and microbial adaptability in soil layers. These results would provide new insights on tillage managements strategies for improving soil conditions in terms of optimizing soil aggregate microstructure–microbes–SOC interactions in the topsoil and subsoil layers.

265. 题目: Microbial Transformation of Dissolved Organic Sulfur during the Oxic Process in 47 Full-Scale Municipal Wastewater Treatment Plants
文章编号: N23010706
期刊: Environmental Science & Technology
作者: Caifeng Liu, Kewei Liao, Jinfeng Wang, Bing Wu, Haidong Hu, Hongqiang Ren
更新时间: 2023-01-07
摘要: Dissolved organic sulfur (DOS) is a significant part of effluent organic matter of wastewater treatment plants (WWTPs) and poses a potential ecological risk for receiving waters. However, the oxic process is a critical unit of biological wastewater treatment for microorganisms performing organic matter removal, wherein DOS transformation and its mechanism are poorly understood. This study investigated the transformation of DOS during the oxic process in 47 full-scale municipal WWTPs across China from molecular and microbial aspects. Surprisingly, evident differences in DOS variations (ΔDOS) separated sampled WWTPs into two groups: 28 WWTPs with decreased DOS concentrations in effluents (ΔDOS < 0) and 19 WWTPs with increased DOS (ΔDOS > 0). These two groups also presented differences in DOS molecular characteristics: higher nitrogen/carbon (N/C) ratios (0.030) and more peptide-like DOS (8.2%) occurred in WWTPs with ΔDOS > 0, implying that peptide-like DOS generated from microbes contributed to increased DOS in effluents. Specific microbe–DOS correlations (Spearman correlation, p < 0.05) indicated that increased effluent DOS might be explained by peptide-like DOS preferentially being produced during copiotrophic bacterial growth and accumulating due to less active cofactor metabolisms. Considering the potential environmental issues accompanying DOS discharge from WWTPs with ΔDOS > 0, our study highlights the importance of focusing on the transformation and control of DOS in the oxic process.

266. 题目: Meeting the heavy-metal safety requirements for food crops by using biochar: An investigation using sunflower as a representative plant under different atmospheric CO2 concentrations
文章编号: N23010705
期刊: Science of the Total Environment
作者: Yiying Wang, Guiying Lin, Xian Li, Ming Hang Tai, Shuang Song, Hugh Tiang Wah Tan, Ken Leong, Elvis Yip Yew Boon, Grace Lee Yoke Chin, Yanjun Dai, Chi-Hwa Wang
更新时间: 2023-01-07
摘要:

Global warming impacts on plant growth and food safety are emerging topics of concern, while biochar as a soil additive benefits plants. This study investigates (1) sunflower plant growth at various biochar concentrations in the soil-compost growing substrate under both ambient (420 ppm) and elevated (740 ppm) atmospheric CO2 concentrations, and (2) concentrations of heavy metals in the growing substrates and organs of the plants. The elevated CO2 concentration benefits the vegetative parts but harms the reproductive parts of the plants. Additionally, the elevated CO2 concentration inhibits the beneficial effects that biochar confers on the plants at the ambient concentration. The optimum biochar concentration at both CO2 levels was found to be 15 %. At the time of harvest, most of the heavy-metal concentrations in the growing substrate increased. It was demonstrated that biochar can reduce the amount of heavy metals that accumulate in the roots and seeds whose heavy-metal concentrations complied with Singapore food safety regulations, while those for the biochar met the proposed Singapore biochar standard's thresholds. Our results show that the proposed Singapore biochar standard is practical and sound.

267. 题目: Impacts of properties of dissolved organic matters on indirect photodegradation of genistein
文章编号: N23010704
期刊: Science of the Total Environment
作者: Chen Yang, Siyu Zhang, Xuehua Li, Xuejiao Zhang, Qing Zhao, Yinghua Li, Haibo Li
更新时间: 2023-01-07
摘要:

Excited triplet states of dissolved organic matters (3DOM*) are one of the most important photochemically-produced reactive intermediates leading to transformation of organic contaminants. However, relationships of photodegradation kinetics of different dissociation states of phenolic organic contaminants with chemical components or properties of 3DOM* are largely unknown. In this study, roles of 3DOM* in photodegradation of polyhydroxy phenolic genistein (Gs) at pH 5, 8 and 12 were investigated taking five kinds of DOM from different sources as examples. Relationships between photodegradation kinetics constants and DOM properties were built. Results showed that the contributions of direct 3DOM*-induced reactions to the total indirect photodegradation of Gs and second-order reaction rate constants (kDOM,Gs) of Gs with 3DOM* increased with pH increases. This was mainly attributed to decreases in vertical ionization energy of Gs at higher pH, endowing Gs with stronger electron donating capacities. kDOM,Gs was found to positively correlate with the specific ultraviolet absorbance at 254 nm, reflecting aromaticity of DOM, and negatively correlate with the absorbance ratio at 254 and 365 nm and contents of dissociated acidic functional groups of DOM, representing molecular weights of DOM, antioxidants and the repulsive forces between 3DOM* and Gs. This study provided a new insight into relationship between DOM properties and indirect photodegradation kinetics of phenolic contaminants in aquatic environments.

268. 题目: Multi-objective operation optimization of spent coffee ground torrefaction for carbon–neutral biochar production
文章编号: N23010703
期刊: Bioresource Technology
作者: Wei-Hsin Chen, Kuan-Ting Lee, Kuan-Yu Ho, Alvin B Culaba, Veeramuthu Ashokkumar, Ching Joon Juan
更新时间: 2023-01-07
摘要:

Many energy-intensive processes are employed to enhance biomass fuel properties to overcome the difficulties in utilizing biomass as fuel. Therefore, energy conservation during these processes is crucial for realizing a circular bioeconomy. This study develops a newly devised method to evaluate SCG biochars’ higher heating value (HHV) and predict moisture content from power consumption. It is found that the increasing rates of HHV immediately follow decreases in power consumption, which could be used to determine the pretreatment time for energy conservation. The non-dominated sorting genetic algorithm II (NSGA-II) maximizes SCG biochar’s HHV while minimizing energy consumption. The results show that producing SCG biochar with 23.98 MJ∙kg−1 HHV requires 20.042 MJ∙kg−1, using a torrefaction temperature of 244 °C and torrefaction time of 27 min and 43 sec. Every kilogram of biochar with an energy yield of 85.93 % is estimated to cost NT$ 12.21.

269. 题目: Pre- and Postapplication Thermal Treatment Strategies for Sorption Enhancement and Reactivation of Biochars for Removal of Per- and Polyfluoroalkyl Substances from Water
文章编号: N23010702
期刊: ACS ES&T Engineering
作者: Zhengyang Wang, Ali Alinezhad, Runze Sun, Feng Xiao, Joseph J Pignatello
更新时间: 2023-01-07
摘要: Exposure to per- and polyfluoroalkyl substances (PFAS) in drinking water poses a major public health threat. Commercial granular activated carbon (GAC) has been used for the sorptive removal of PFAS in practical applications. Biochar is a possible cheaper alternative to GAC for small-scale water treatment systems. Here, we report a strategy for employing biochar for PFAS removal that combines post-pyrolysis modification, which greatly improves performance, with a reactivation step that enables its reuse. Modification entails brief postpyrolysis air oxidation at 400 °C, which considerably enlarges pore size and specific surface area and thereby increases the solid-to-water distribution ratio, KD, of individual PFAS by as much as 3 orders of magnitude. In some cases (e.g., perfluorooctanoic acid) the KD was comparable to that of commercial GAC. The sorbed PFAS could be decomposed by brief thermal reactivation of the spent biochar at 500 °C in N2 or air. After thermal reactivation in air, the biochars exhibited even greater PFAS KD values in a second cycle. While thermal reactivation of a GAC in air could be achieved, as well, sorption affinity for the shorter-chain PFAS was noticeably reduced. Overall, this study points to a new strategy of using biochars for PFAS removal.

270. 题目: Enrichment and analysis methods for trace dissolved organic carbon in reverse osmosis effluent: A review
文章编号: N23010701
期刊: Science of the Total Environment
作者: Xiaowen Chen, Nan Huang, Wenlong Wang, Qi Wang, Hong-Ying Hu
更新时间: 2023-01-07
摘要:

Reverse osmosis (RO) is an essential unit for producing high-quality ultrapure water. The increasingly severe water shortage and water quality deterioration result in reclaimed water as an alternative source for ultrapure water production. However, when using reclaimed water as water sources, the dissolved organic carbon (DOC) in RO permeate exhibits higher concentration and more sophisticated components than when using clean water sources, thus affecting the effluent quality of ultrapure water and the effectiveness of subsequent treatment processes. To optimize the treatment processes, it is crucial to analyze the components of DOC. This review summarizes the enrichment and analysis methods of trace organic matter, and provides recommendations for the analysis and characterization of DOC in RO permeate. The study summarizes the operating conditions and enrichment properties of different enrichment methods, including solid-phase extraction, liquid-liquid extraction, purge-and-trap, lyophilization and rotary evaporation for low-concentration organic compounds, compares the applicability and limitations of different enrichment methods, and proposes the principles for the selection of enrichment methods. In this review, we discuss the application of mass spectrometry (including Fourier transform ion cyclotron resonance mass spectrometry) in the analysis of DOC components, and focus on data processing as the key procedure in analysis of DOC in RO permeate. Despite the advantages of mass spectrometry, an applicable workflow and open-source database are required to improve the reliability of the analysis. The treatability properties of DOC are suggested to be determined by analyzing the component characteristics or in combination with common removal techniques. This study provides theoretical support for a comprehensive analysis of DOC in RO permeates to improve the removal effect.

271. 题目: Algal biochar mediated detoxification of plant biomass hydrolysate: Mechanism study and valorization into polyhydroxyalkanoates
文章编号: N23010619
期刊: Bioresource Technology
作者: Shashi Kant Bhatia, Ranjit Gurav, Do-Hyun Cho, Byungchan Kim, Hee Ju Jung, Su Hyun Kim, Tae-Rim Choi, Hyun-Joong Kim, Yung-Hun Yang
更新时间: 2023-01-06
摘要:

In this study, fourteen types of biochar produced using seven biomasses at temperatures 300 °C and 600 °C were screened for phenolics (furfural and hydroxymethylfurfural (HMF)) removal. Eucheuma spinosum biochar (EB-BC 600) showed higher adsorption capacity to furfural (258.94 ± 3.2 mg/g) and HMF (222.81 ± 2.3 mg/g). Adsorption kinetics and isotherm experiments interpreted that EB-BC 600 biochar followed the pseudo-first-order kinetic and Langmuir isotherm model for both furfural and HMF adsorption. Different hydrolysates were detoxified using EB-BC 600 biochar and used as feedstock for engineered Escherichia coli. An increased polyhydroxyalkanoates (PHA) production with detoxified barley biomass hydrolysate (DBBH: 1.71 ± 0.07 g PHA/L), detoxified miscanthus biomass hydrolysate (DMBH: 0.87 ± 0.03 g PHA/L) and detoxified pine biomass hydrolysate (DPBH: 1.28 ± 0.03 g PHA/L) was recorded, which was 2.8, 6.4 and 3.4 folds high as compared to undetoxified hydrolysates. This study reports the mechanism involved in furfural and HMF removal using biochar and valorization of hydrolysate into PHA.

272. 题目: Elucidation of aniline adsorption-desorption mechanism on various organo-mineral complexes.
文章编号: N23010618
期刊: Environmental Science and Pollution Research
作者: Yan Ma, Xinyi Wu, Tong Wang, Shengkun Zhou, Biying Cui, Haoqun Sha, Bowen Lv
更新时间: 2023-01-06
摘要: Complexes formed by organic matter and clay minerals, which are active components of soil systems, play an important role in the migration and transformation of pollutants in nature. In this study, humic-acid-montmorillonite (HA-MT) and humic-acid-kaolin (HA-KL) complexes were prepared, and their structures before and after the adsorption of aniline were analyzed. The aniline adsorption-desorption characteristics of complexes with different clay minerals and varying HA contents were explored using the static adsorption-desorption equilibrium method. Compared with the pristine clay minerals, the flaky and porous structure of the complexes and the aromaticity were enhanced. The adsorption of aniline on the different clay mineral complexes was nonlinear, and the adsorption capacity increased with increasing HA content. Additionally, the adsorption capacity of HA-MT was higher than that of HA-KL. After adsorption, the specific surface area of the complexes decreased, the surfaces became more complicated, and the aromaticity decreased because aniline is primarily adsorption onto the complexes via aromatic rings. Aniline was adsorbed onto the complexes via spontaneous exothermic physical adsorption. The amount of aniline desorbed from the complexes increased with increasing HA content, and a lag in desorption was observed, with a greater lag for HA-KL than for HA-MT.

273. 题目: Pyrolysis characteristics, kinetics, and biochar of fermented pine sawdust-based waste.
文章编号: N23010617
期刊: Environmental Science and Pollution Research
作者: Yiteng Zhang, Jun Hu, Xingxing Cheng, Mudassir Hussain Tahir
更新时间: 2023-01-06
摘要: The objective of current study is to explore the energy recovery potential of fermentation residues. In this perspective, pyrolysis characteristics, kinetics, and modified biochar derived from pine sawdust after fermentation (FPD) were determined, and comparison was established with pine sawdust (PD). The variation range of comprehensive pyrolysis index (CPI) values of FPD was found 6.51 × 10-7-16.38 × 10-7%2·min-2·°C-3, significantly higher than that of untreated samples determined under the same experimental conditions. The average activation energy of FPD was 367.95 kJ/mol, 389.45 kJ/mol, and 346.55 kJ/mol calculated by Flynn-Wall-Ozawa (FWO) method, Kissinger-Akahira-Sonuse (KAS), and Starink method respectively, and importantly, these values are much higher than those of PD. Additionally, fermentation could enhance the adsorption capacity for methylene blue of biochar from 0.76 mg/g to 1.6 mg/g due to the abundant surface functional groups and three-dimensional internal pore structure. The adsorption pattern of fermented pine wood shifted from chemisorption dominated to the synergetic adsorption of surface functional groups adsorption and intragranular filling. These results show that FPD has favorable pyrolytic properties, and the derived biochar has adsorption properties, which is the basis for designing pyrolysis process and reusing fermentation residues. HIGHLIGHTS: The FPD has higher values of CPI and activation energy than the PD. FPD-derived biochar has higher adsorption capacity than PD-derived biochar. The fermentation improves the pyrolysis performance. The fermentation enhances adsorption capacity due to unique structure of biochar.

274. 题目: Geochemistry of Late Permian coals from the Moxinpo mine, Chongqing, Southwestern China: Emphasis on petrology, minerals, and organic matter
文章编号: N23010616
期刊: Applied Geochemistry
作者: Qingfeng Lu, Shenjun Qin, Wenfeng Wang, Kang Gao, Jingkai Xing
更新时间: 2023-01-06
摘要:

The indicative significance of organic matter in fossil fuels, particularly polycyclic aromatic compounds (PACs), is a current research hotspot. Petrology, minerals, and organic matter in Late Permian coals from the Moxinpo (MXP) mine located in Chongqing, southwestern China, were analyzed to evaluate the coal rank, coal-forming material source and thermal maturity of organic matter, and sedimentary environment of the peat swamp. Vitrinite and inertinite were dominated by collotelinite, collodetrinite, inertodetrinite, fusinite, and semifusinite. Owing to the high maturity of the coals, liptinite was not observed under the microscope. Clay (kaolinite) and pyrite were the primary minerals in the MXP coals, followed by calcite, quartz, trace amounts of anatase, gypsum, xenotime, and bastnaesite. The minerals in the MXP coals were authigenic primarily in the epigenetic stage. The extract yield of organic matter in coals was low (0.30%), and the saturated and aromatic fractions accounted for approximately 60% of the extractable organic matter. Low ratios of saturated to aromatic compounds reflected the terrestrial higher plants input and high maturity level of the coals. The extracted yield in the host rock samples was much lower than in the coals, while the proportion of saturated hydrocarbons was relatively high. The marine-continental transitional sedimentary environment, distribution of n-alkanes, ∑ C21/∑ C22+, and pristane (Pr)/n-C17 vs. phytane (Ph)/n-C18 indicated that the organic matter originated from the input of terrestrial higher plants and was accompanied by the contribution of marine lower phytoplankton and aquatic organisms. The coal-forming environment of the coal seam was reductive according to the Pr/Ph and sulfur-containing compounds of dibenzothiophenes and benzonaphthothiophenes. The thermodynamic stability controls the presence of polycyclic aromatic hydrocarbons in extractable organic matter. Isomeric compounds with high stability had higher concentrations, such as 2-methylnaphthalene, 2,6 + 2,7-DMN, 4- methylbiphenyl, and 2- methylphenanthrene.

275. 题目: Response of dissolved organic matter chemistry to flood control of a large river reservoir during an extreme storm event
文章编号: N23010615
期刊: Water Research
作者: Kai Wang, Yu Pang, Yuanbi Yi, Shouye Yang, Yuntao Wang, Chen He, Quan Shi, Ding He
更新时间: 2023-01-06
摘要:

With the frequent occurrence of extreme floods under global climate change-induced storm events, reservoir operation has been highlighted for river flood control, complicating the transport and transformation of riverine dissolved organic matter (DOM), one of the largest reactive carbon pools on earth. In particular, the response of riverine DOM chemistry to reservoir flood control during extreme storm events is still unclear. To fill this knowledge gap, the mechanism of DOM variation in Yangtze River with the world's largest Three Gorges Reservoir (TGR) operation during an extreme storm event was explored. Optical and molecular properties of DOM varied significantly from upstream to downstream in non-TGR area, while no significant variation in DOM chemistry was observed in TGR area. The results uncovered a short time transformation of DOM from non-TGR area to TGR area, demonstrating that although storm event induced chemodiversity bloom of riverine DOM, flood control of TGR “re-constrained” DOM to more similar chemistry mainly under the influence of turbidity involved DOM transformation (e.g., adsorption/desorption and flocculation). Furthermore, combined with the hydrological information, we found that although TGR temporarily blocked dissolved organic carbon (DOC) flow during the flood event, the abundance of biologically recalcitrant DOC increased in TGR, which would contribute to its further transportation to downstream watershed. This study emphasizes the impact of TGR on extreme storm event-induced DOM dynamics, which also hints a better understanding of the crucial role of anthropogenic activity in affecting carbon cycling under extreme climate change.

276. 题目: Sources and chemical stability of soil organic carbon in natural and created coastal marshes of Louisiana
文章编号: N23010614
期刊: Science of the Total Environment
作者: Megan Kelsall, Tracy Quirk, Carol Wilson, Gregg A Snedden
更新时间: 2023-01-06
摘要:

Coastal marshes are globally important for sequestering carbon, yet sea-level rise and anthropogenic stressors can reduce their capacity as carbon sinks. Marsh restoration can offset a portion of carbon loss through the degradation of natural marshes, but potential differences in the sources and stability of soil organic carbon (SOC) between created and natural marshes may affect their function as a long-term carbon sink. Here, we examine the sources and chemical stability of SOC in natural and created marshes across the Gulf coast of Louisiana, USA. Marshes were examined along an estuarine salinity gradient in a former interdistributary basin of the Mississippi River Delta and in six created marshes across a 32-year chronosequence and a natural reference marsh (n = 6) in the Chenier Plain. Carbon source was assessed using δ13C analysis and chemical stability was determined through an acid hydrolysis digestion that removed labile carbon (LC). Soil δ13C values suggested that the local vegetation dominated SOC in all natural marshes although brackish marshes had a mix of sources and degradation of SOC. Recalcitrant carbon (RC) was 72.2 ± 0.5 % of SOC across fresh, brackish and saline marshes. The depth-averaged RC accumulation rate was almost three times greater than LC accumulation rate, yet both contributed significantly to accretion and long-term SOC accumulation (124–132 g m−2 y−1 in natural marshes). RC and SOC accumulation rate increased with mineral sediment accumulation rate. For the created marshes, SOC became increasingly recalcitrant due to an increase in in-situ plant inputs, but accumulation rates were lower than the natural marshes. Overall, this study illustrates that natural marshes have a large stock of RC from the vegetation while dredge sediment created marshes have no plant-derived carbon initially, which accumulates slowly thereafter. Restoration practices may be improved by preserving and augmenting these deteriorating but carbon-rich natural marshes.

277. 题目: Depth-dependent response of particulate and mineral-associated organic carbon to long-term throughfall reduction in a subtropical natural forest
文章编号: N23010613
期刊: Catena
作者: Siyi Sun, Xiaofei Liu, Shengxu Lu, Pingli Cao, Dafeng Hui, Ji Chen, Jianfen Guo, Yusheng Yang
更新时间: 2023-01-06
摘要:

Climate change has altered the precipitation patterns and prolonged the drought season in subtropical areas, which affects forest productivity and soil carbon (C) cycling. However, the response of different soil organic C (SOC) fractions to the reduction in precipitation and the potential mechanisms remain poorly understood in subtropical forests. In this study, we examined the effects of long-term (9 years) throughfall reduction on SOC fractions, including particulate organic C (POC) and mineral-associated organic C (MAOC), dissolved organic C (DOC), microbial biomass C (MBC), mycorrhizal fungal biomass, and fine-root biomass of two soil layers (0–10 cm and 40–60 cm) in a subtropical Castanopsis carlesii forest. The results showed that throughfall reduction had a significant effect on soil C cycling in the topsoil but not in the subsoil. Throughfall reduction significantly decreased soil POC but increased soil MAOC in the topsoil. Meanwhile, soil MBC, DOC, fine-root biomass, and mycorrhizal fungal biomass were reduced with throughfall reduction. Regression and partial least squares path modeling analyses revealed that soil POC was positively correlated with fine-root biomass, necromass, and mycorrhizal fungal biomass, whereas negative relationships were observed for topsoil MAOC. The results from this study implied that fine roots play an important role in the contrasting responses of POC and MAOC to throughfall reduction in the topsoil. Such information is essential for understanding the roles of plant roots and mycorrhizal fungi in the soil C cycle in subtropical forests under drought conditions.

278. 题目: Nitrogen-doped Biochar (N-doped BC) and Iron/Nitrogen Co-doped Biochar (Fe/N co-doped BC) for Removal of Refractory Organic Pollutants
文章编号: N23010612
期刊: Journal of Hazardous Materials
作者: Shakeel Ahmad, Linan Liu, Shicheng Zhang, Jingchun Tang
更新时间: 2023-01-06
摘要:

The presence of refractory organic pollutants (ROPs) in the ecosystem is a serious concern because of their impact on environmental constituents as well as their known or suspected ecotoxicity and adverse health effects. According to previous studies, carbonaceous materials, such as biochar (BC), have been widely used to remove pollutants from ecosystems owing to their desirable features, such as relative stability, tunable porosity, and abundant functionalities. Nitrogen (N)-doping and iron/nitrogen (Fe/N) co-doping can tailor BC properties and provide supplementary functional groups as well as extensive active sites on the N-doped and Fe/N co-doped BC surface, which is advantageous for interaction with and removal of ROPs. This review investigates the impact of N-doped BC and Fe/N co-doped BC on the removal of ROPs through adsorption, activation oxidation, and catalytic reduction due to the synergistic Fe, N, and BC features that modify the physicochemical properties, surface functional groups, and persistent free radicals of BC to aid in the degradation of ROPs. Owing to the attractive properties of N-doped and Fe/N co-doped BCs for the removal of ROPs, this review focuses and evaluates previous experimental investigations on the manufacturing (including precursors and influencing parameters during manufacturing) and characterizations of N-doped and Fe/N co-doped BCs. Additionally, the effective applications and mechanisms of N-doped and Fe/N co-doped BCs in adsorption, activation oxidation, and reductive remediation of ROPs are investigated herein. Moreover, the application of N-doped and Fe/N co-doped BC for progressive environmental remediation based on their effectiveness against co-pollutants, regeneration, stability, affordability, and future research prospects are discussed.

279. 题目: Carbon farming: Are soil carbon certificates a suitable tool for climate change mitigation?
文章编号: N23010611
期刊: Journal of Environmental Management
作者: Carsten Paul, Bartosz Bartkowski, Cenk Dönmez, Axel Don, Stefanie Mayer, Markus Steffens, Sebastian Weigl, Martin Wiesmeier, André Wolf, Katharina Helming
更新时间: 2023-01-06
摘要:

Increasing soil organic carbon (SOC) stocks in agricultural soils removes carbon dioxide from the atmosphere and contributes towards achieving carbon neutrality. For farmers, higher SOC levels have multiple benefits, including increased soil fertility and resilience against drought-related yield losses. However, increasing SOC levels requires agricultural management changes that are associated with costs. Private soil carbon certificates could compensate for these costs. In these schemes, farmers register their fields with commercial certificate providers who certify SOC increases. Certificates are then sold as voluntary emission offsets on the carbon market.

In this paper, we assess the suitability of these certificates as an instrument for climate change mitigation. From a soils' perspective, we address processes of SOC enrichment, their potentials and limits, and options for cost-effective measurement and monitoring. From a farmers’ perspective, we assess management options likely to increase SOC, and discuss their synergies and trade-offs with economic, environmental and social targets. From a governance perspective, we address requirements to guarantee additionality and permanence while preventing leakage effects. Furthermore, we address questions of legitimacy and accountability.

While increasing SOC is a cornerstone for more sustainable cropping systems, private carbon certificates fall short of expectations for climate change mitigation as permanence of SOC sequestration cannot be guaranteed. Governance challenges include lack of long-term monitoring, problems to ensure additionality, problems to safeguard against leakage effects, and lack of long-term accountability if stored SOC is re-emitted. We conclude that soil-based private carbon certificates are unlikely to deliver the emission offset attributed to them and that their benefit for climate change mitigation is uncertain. Additional research is needed to develop standards for SOC change metrics and monitoring, and to better understand the impact of short term, non-permanent carbon removals on peaks in atmospheric greenhouse gas concentrations and on the probability of exceeding climatic tipping points.

280. 题目: Extracting compositional blocks of alginate-like extracellular polymers (ALE) from conventional activated sludge (CAS)
文章编号: N23010610
期刊: Science of the Total Environment
作者: Chen Shi, Run-Gen Zeng, Li-Ting Hao, Xiao-Di Hao, Ji Li
更新时间: 2023-01-06
摘要:

As a highly added value material, alginate-like extracellular polymers (ALE) can be extracted from extracellular polymeric substances (EPS) from aerobic granular sludge (AGS). In fact, conventional activated sludge (CAS) also contains a certain amount of ALE. As CAS is widely used everywhere, waste activated sludge (WAS) from CAS is huge in its absolute amount. Although the ALE property of CAS was identified not so good as that from AGS, the mechanisms remains unclear. For this reason, it is necessary to unravel the chemically compositional blocks of ALE. Referring to natural alginate, ALE can be separated into three compositional blocks: GGL, GML and MML (like units containing guluronate or mannuronate), associated with other compositions including protein (PN), polysaccharide (PS), phosphorus (P), humic acid (HA). With real WAS from CAS, ALE was extracted and three blocks were separated: GGL = 54 %, GML = 42 % and MML = 4 % in weight, which is similar to the previous study. Moreover, the GGL blocks in CAS were obviously lower than AGS, up to by 3/1-2/1. And the GGL and MML blocks in CAS were much higher than AGS, by more than 1/2. Different compositional blocks of ALE in AGS and CAS should be the reason forming different properties in applications. For this reason, a further study will be initiated to dispense/reorganize three blocks of ALE from CAS for expanding its potential applications, based on the compositional blocks of ALE from AGS.

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