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361. 题目: Thermal stability of sedimentary organic carbon in a large river dominated marginal sea
文章编号: N24100207
期刊: Science of the Total Environment
作者: Siyu Chen, Peng Yao, Zheng Wang, Bin Zhao, Le Wang, Lulu Han, Nan Wang, Xiwen Ye, Chao Gao
更新时间: 2024-10-02
摘要: The thermal stability of organic carbon (OC) in marine sediments is one of the critical factors that influences its burial efficiency in marine environments. However, the distribution patterns and influencing factors of the thermal stability of OC in marginal seas remain poorly understood. In this study, we conducted the thermal gravimetric analysis (TGA) of OC in surface sediments of the Changjiang Estuary (CE) and its adjacent East China Sea (ECS) shelf. Both labile and refractory organic matter (OML and OMR) contents derived from the TGA were higher in the CE and Zhe-Min Coast (ZMC) mobile muds relative to those in the sandy areas. The average Carbon Reactivity Index (CRI) is 69.3 ± 4.2 %, ranging from 62.8 % to 85.1 %. Most of the stations in the CE and ZMC mobile muds were characterized by relatively low CRI values, while only some stations in the inner estuary and outer shelf had higher CRI values. As a result, the CRI values correlated reversely with the OC contents and positively with the median grain size, especially in sandy sediments. Despite being sandy sediments, there were significant differences in the thermal stability of OC among the three different sandy sediment areas, with the highest CRI value in the inner estuary, lower CRI values in the outer estuary and outer shelf sediments, possibly related to the sources and composition of OC in different regions as shown by the negative correlation between CRI and δ13C for sandy sediments. Compared with certain European marginal seas, the sedimentary OC (SOC) in the CE and ECS shelf exhibits greater thermal stability, which is probably linked to the reduced preservation efficiency of OC caused by the extensive sediment dynamics in this area. This study supports the notion that organo-mineral interactions and the sources are two major factors controlling the reactivity of OC.

362. 题目: Differential response of subterranean microbiome to exogenous organic matter input in a cave ecosystem
文章编号: N24100206
期刊: Science of the Total Environment
作者: Xiaoyu Cheng, Rui Zhao, Paul L E Bodelier, Yuyang Song, Kang Yang, Olli H Tuovinen, Hongmei Wang
更新时间: 2024-10-02
摘要: As a recurrent climatic phenomenon in the context of climate change, extreme rainstorms induce vertical translocation of organic matter and increase moisture content in terrestrial ecosystems. However, it remains unclear whether heavy rainstorms can impact microbial communities in the deep biosphere by modulating organic matter input. In this study, we present findings on the different responses of bacterial and fungal communities in a subsurface cave to rainstorms and moisture variations through field surveys and microcosm experiments. During periods of rainstorms, the influx of dissolved organic matter (DOM) from soil overlying the cave into cave sediments significantly enhanced the correlation between core bacteria and environmental factors, particularly fluorescence spectral indices. The resource utilization of core bacteria was diminished, while the functional diversity of core fungi remained relatively unaltered. We also performed simulated experiments with restricted external DOM inputs, in which DOM content was observed to decrease and microbial diversity increase in response to artificially increased moisture content (MC). The niche breadth of core bacteria decreased and became more closely associated with DOM as the MC increased, while the niche breadth of core fungi remained predominantly unchanged. Compared to fungi, cave bacteria exhibited higher sensitivity towards variations in DOM. The core microbiome can efficiently utilize the available organic matter and participate in nitrogen- and sulfur-related metabolic processes. The study systematically revealed distinct microbial responses to rainstorm events, thereby providing valuable insights for future investigations into energy utilization within deep biospheres.

363. 题目: Blue carbon dynamics across a salt marsh-seagrass ecotone in a cool-temperate estuary
文章编号: N24100205
期刊: Plant and Soil
作者: Tiaan Engelbrecht, Sophie von der Heyden, Andrew Ndhlovu
更新时间: 2024-10-02
摘要:

Background

Seagrass and salt marsh ecosystems are recognised for their role in climate change mitigation and adaptation given their carbon storage potential. However, factors driving variability in blue carbon ecosystems are understudied, yet are important to account for.

Aims

Examine the variability of sediment organic carbon (SOC) and its drivers (seagrass morphometrics and sediment nutrients) at different spatial scales; > 1 km, ~ 150 m and ~ 10 m across the salt marsh-seagrass ecotone.

Methods

We collected the top 5 cm of sediment in the Olifants River Estuary, a cool-temperate system in South Africa. Using a line transect approach, we sampled across the salt marsh-seagrass ecotone (~ 10 m) in triplicate transects (~ 50 m apart) at three sampling sites (1–3 km) and analysed for SOC and elemental nutrient (nitrogen and phosphorus) content. Seagrass morphometrics (shoot density, leaf length and number per shoot) were measured.

Results

There was significant (P < 0.05) spatial heterogeneity in SOC stocks between sites (1–3 km) and between salt marshes and seagrass, but low variability at ~150 m. We detected a significant decrease in SOC from salt marsh towards the seagrass edge, with seagrass SOC remaining uniform. Nitrogen content was positively correlated with SOC in seagrass and salt marshes (P < 0.05), but seagrass morphometrics were not significant drivers of SOC.

Conclusions

The dynamics of blue carbon differ between salt marshes and seagrass, with spatial heterogeneity of SOC at scales > 1 km, suggesting that future BC assessments need to account for spatial heterogeneity to improve the accuracy of carbon removal estimates.

364. 题目: Investigations on adsorptive removal of PVC microplastics from aqueous solutions using Pinus roxburghii–derived biochar
文章编号: N24100204
期刊: Environmental Science and Pollution Research
作者: Misbah Bashir, Manzoor Ahmad Ahanger, Khalid Muzamil Gani
更新时间: 2024-10-02
摘要:

This study investigates the adsorption mechanisms of pine bark biochar (BC) and modified pine bark biochar (MBC) in the removal of polyvinyl chloride (PVC) microplastics from aqueous solutions, with a significant focus on resource recovery from pine residues which is one of the key Himalayan Forest byproducts. The research findings highlighted the optimal adsorption capacity of biochar at 131.5 mg/g achieved after 6 h of contact time, with a pH of 10 and a PVC microplastic concentration of 200 mg/L. The primary mechanisms of PVC microplastic adsorption involved ion exchange and physical adsorption, driven by forces such as Vander-Waals, London forces, and electrostatic forces. Thermodynamic analysis showed the exothermic nature of the PVC and BC/MBC interaction, with spontaneous adsorption occurring within the temperature range of 10 to 40 °C. Isotherm and kinetic models fit well with Temkin model and PSO kinetics, as indicated by R2 values exceeding 0.9. Particularly, MBC exhibited superior removal efficiency and adsorption capacity compared to its precursor, reaching an optimum adsorption capacity of 156.08 mg/g with a removal efficiency of 78%, surpassing the performance of BC. This research contributes valuable insights into potential applications of BC for PVC removal and underscores the effectiveness of MBC in achieving enhanced adsorption outcomes.

365. 题目: Long-Term Effects of Arable and Tree Cropping Systems on Soil Organic Carbon and Nitrogen Dynamics in a Tropical Agroecological Transition Zone
文章编号: N24100203
期刊: Land Degradation & Development
作者: Peter Bilson Obour, Ohene Asa Bosompem, Kwadwo Owusu, Eric Oppong Danso, Finn Plauborg, Emmanuel Arthur
更新时间: 2024-10-02
摘要: Continuous cropping can affect soil carbon and nitrogen stocks and litter decomposition, but research on smallholder farms in Africa is limited. This study, conducted from 2020 to 2023 in Ghana's forest-savanna transition zone, examined four cropping systems: continuous maize monocrop (M), maize rotated with legumes (ML), young cashew intercropped with maize or legumes (YCM/L), and mature cashew (MC). The objective was to assess the long-term impact of the cropping systems on soil organic carbon (SOC), nitrogen (N) stocks, and soil organic matter (SOM) decomposition rates using the tea bag protocol. Results showed significant variability in SOC and N stocks across the systems. At a 0–15 cm depth, SOC in the MC and M systems was 160% and 149% higher than in the YCM/L system. At 15–30 cm, SOC in the M and MC systems was 86% and 132% higher than in YCM/L. Soil nitrogen stocks followed a similar trend, with MC and M systems showing 94%–199% higher values than YCM/L at both depths. SOM decomposition rates for green and rooibos tea in the MC and ML systems were statistically similar after 90 days of incubation (p > 0.05). This study, the first to use the tea bag protocol in Ghanaian soils, revealed that mature cashew and sustainable practices, such as adding maize stover, can enhance SOC and N stocks in highly weathered tropical soils. These findings underscore the potential for specific cropping systems to improve soil health on smallholder farms.

366. 题目: European croplands under climate change: Carbon input changes required to increase projected soil organic carbon stocks.
文章编号: N24100202
期刊: Science of the Total Environment
作者: Elisa Bruni, Emanuele Lugato, Claire Chenu, Bertrand Guenet
更新时间: 2024-10-02
摘要: Increasing soil organic carbon (SOC) stocks in agricultural systems is a pivotal strategy for promoting soil health and mitigating climate change. Global initiatives have set ambitious targets, aspiring to achieve an annual SOC stock increase of 4 ‰. In the European Union, the recently approved Nature Restoration Law aims to increase SOC stock trends in the top 30 cm of cropland mineral soils. However, current monitoring and reporting practices in some countries rely on simplistic SOC models with default parameters, which may not provide reliable predictions. In this paper, we study the feasibility of a 4 ‰ target in European croplands (i.e., an aspirational target proposed by The international 4 per 1000 Initiative), through estimations of required C input changes. To ensure robust predictions, we propose a novel calibration approach that links model parameters to pedo-climatic variables via statistical relationships from 16 long-term experiments. The effectiveness of the method is evaluated for three SOC models across 4281 sites from the European LUCAS soil survey. Our findings demonstrate that the statistical calibration of the multi-model ensemble improves the accuracy of 2015 and 2018 SOC stock predictions, compared to default parameterization. This improvement was however mainly due to the substantial enhancement of one of the models. According to the weighted multi-model mean, median C input changes to reach a 4 ‰ target for Northern, Central, and Southern Europe stand at 1.85, 1.20, and 0.13 Mg C ha-1 yr-1 under RCP 2.6, and 2.21, 1.26, and -0.10 Mg C ha-1 yr-1 under RCP 6.0, respectively. To achieve the aspirational 4 ‰ target, estimated C input change requirements exceed the predicted changes in net primary productivity under RCP 2.6 and RCP 6.0. This emphasizes the importance of strategic land-use and land-management interventions to enhance SOC stocks.

367. 题目: Polystyrene microplastics enhanced the photo-degradation and -ammonification of algae-derived dissolved organic matters
文章编号: N24100201
期刊: Journal of Hazardous Materials
作者: Jia Liang, Xiao Tan, Imran Ali, Zhipeng Duan, Jiang Huang, Rui Zhu
更新时间: 2024-10-02
摘要: Algae-derived organic matter (ADOM) is a key source of chromophoric dissolved organic matter (CDOM) in natural waters. When exposed to solar irradiation, ADOM undergoes gradual degradation and transformation. The escalating presence of microplastics (MPs) can act as a novel type of environmental photosensitizer, however its impacts on ADOM photodegradation remains largely unexplored. Thus, in this study, ADOM were extracted from four common algal species (Microcystis aeruginosa, Synechococcus sp., Chlorella pyrenoidosa and Scenedesmus obliquus) and exposed to UV irradiation with or without polystyrene (PS) MPs, namely ADOM+PS groups and ADOM groups, respectively. The results indicated that a more rapid degradation of amino acid-like substances (~38% vs. ~22%) and more ammonia products (1.86 vs. 1.21 mg L-1) were observed in the ADOM+PS groups compared to the ADOM groups after a five-day exposure. This enhanced photodegradation might be attributed to the production of environmentally persistent free radicals and reactive species during the photoaging of PS. Furthermore, PS-derived high electron transfer belt activity of ADOM led to the production of highly aromatic and humified products. These humic-like products could potentially accelerate the degradation of amino acid-like compounds by exciting the generation of excited triplet CDOM. This study underscores the role of MPs as environmental photosensitizers in promoting ADOM degradation and ammonia generation, providing insights on the transformation of ADOM mediated by emerging pollutants and its impact on aquatic carbon and nitrogen cycles.

368. 题目: Biochar additions shape soil microbial community and leaf bioactive-substance accumulation in Cyclocarya paliurus grown on an acidic soil
文章编号: N24100120
期刊: Applied Soil Ecology
作者: Ziyu Lan, Rui Deng, Xulan Shang, Scott X Chang, Shengzuo Fang
更新时间: 2024-10-01
摘要: Cyclocarya paliurus, a new resource for food ingredients, is mainly planted on nutrient-poor and acidic soil in China, whereas enhancing bioactive substances using environmentally friendly and cost-effective methods (such as biochar) is urgently needed. However, biochar effects on soil properties and crop productivity were dependent on biochars produced from feedstocks, especially little information is available on influence of various biochar amendments on the bioactive-substance accumulation of C. paliurus grown on acidic soils. Thus, a pot experiment was performed to investigate effects of three biochar types (wheel wingnut, rice husk and bamboo biochars) and three addition doses (5, 15 and 25 %, v/v) on soil pH, soil microbial populations, leaf nutrient and bioactive-substance concentrations, and plant growth. Biochar addition significantly increased soil pH and altered soil microbial diversity and composition, leaf nutrient and bioactive-substance concentrations, and growth of C. paliurus. Two hundred days after biochar addition, soil pH increased by 1.4–32.0 %, whereas the effect on soil microbial diversity and composition was biochar type and dose-dependent. Overall, biochar addition shaped the diversity and composition of soil bacterial and fungal communities via a combination of direct and indirect effects, but a direct effect of biochar addition was only significantly correlated with fungal community composition and fungal Shannon index (p < 0.05). Biochar addition also reduced carbon (C)/nitrogen (N) and carbon/phosphorus (P) ratios in the leaves by 5.5–33.4 and 7.4–56.0 %, respectively. Biochar effects on biomass production and leaf bioactive-substance contents were also biochar type and dose-dependent. However, the greatest accumulations of total polyphenol, total flavonoids and total triterpenoids were achieved by adding 5 % wheel wingnut biochar, with increases of 33.2, 52.1 and 52.3 %, respectively, compared to the control. The concentrations of total polyphenol, total flavonoids and total triterpenoids were negatively correlated with the leaf N, P and potassium concentrations but positively with leaf C/N and C/P. Results from the partial least squares path modeling suggested that soil microbial composition was a key moderator for accumulating bioactive substances in leaves. We conclude that 5 % biochar from wheel wingnut pruning residue is optimal for increasing bioactive substance accumulation in C. paliurus.

369. 题目: Characteristics of light absorption and environmental effects of Brown carbon aerosol in Chongqing during summer and winter based on online measurement: Implications of secondary formation
文章编号: N24100119
期刊: Atmospheric Environment
作者: Hong Wu, Chao Peng, Tianyu Zhai, Jingcheng Deng, Peili Lu, Zhenliang Li, Yang Chen, Mi Tian, Zhier Bao, Xin Long, Fumo Yang, Chongzhi Zhai
更新时间: 2024-10-01
摘要: Light-absorbing organic carbon (i.e., brown carbon, BrC) significantly contributes to light absorption and radiative forcing in the atmospheric particles. However, the secondary formation of BrC and optical properties of secondary BrC are poorly understood. In this study, we analyzed and evaluated the light absorption and environmental effects of BrC and secondary BrC from July 1st to 31st, 2022 (summer) and January 20th to February 20th, 2023 (winter) in Chongqing. BrC and secondary BrC light absorption were estimated via a seven-wavelength aethalometer and the statistical approach. The average values of secondary BrC light absorption (AbsBrC,sec,λ) accounted for 46.2–56.5% of AbsBrC. AbsBrC,370 and AbsBrC,sec,370 were significantly higher during winter (26.2 ± 13.2 and 9.1 ± 5.2 Mm−1 respectively) than that during summer (7.2 ± 4.1 and 5.2 ± 3.5 Mm−1 respectively) (p < 0.001), suggesting secondary formation played an essential role in BrC. A diurnal cycle of AbsBrC,sec,370 was explained by the photobleaching of light-absorbing chromophores under the oxidizing conditions in the daytime, and the formation of chromophores via aqueous reactions with NH4+ and NOx after sunset during winter. PSCF analysis showed that transport of anthropogenic emissions from the northeastern and southeastern areas of Chongqing was the important source of the secondary BrC in PP during winter. During winter, the average values of SFEBrC and SFEBrC,sec were 31.9 and 27.4 W g−1 lower than that during summer (64.7 and 44.5 W g−1), respectively. In contrast, J[NO2] values of SFEBrC and SFEBrC,sec decreased by 23.3% and 8.7% during winter higher than that during summer (19.9% and 5.6%), indicating that BrC and secondary BrC cause substantial radiative effects and atmospheric photochemistry. Overall, this study is helpful in understanding the characterization and secondary formation of BrC and accurately evaluating the environmental effects of BrC in Chongqing.

370. 题目: Phosphorus-loaded coconut biochar: A novel strategy for cadmium remediation and soil fertility enhancement
文章编号: N24100118
期刊: Ecotoxicology and Environmental Safety
作者: Xiao Chu, Yingzhi Rao, Jizhen Qu, Jingmin Zhang, Ri Zeng, Yipeng Kong, Zimin Xi, Zhiqiang Zhu, Dong Li, Jianhong Li, Qingjie Zhao
更新时间: 2024-10-01
摘要: The management of cadmium (Cd) contamination in soils poses a significant environmental challenge. This study investigates the effectiveness of phosphorus (P)-loaded coconut biochar, synthesized at various pyrolysis temperatures (450°C, 500°C, 550°C, and 600°C), in immobilizing Cd and enhancing P availability in soil environments. The biochar underwent a series of treatments including activation and P enrichment, followed by incubation trials to evaluate its performance in Cd immobilization and P bioavailability enhancement across varying soil concentrations (0.5 %, 1.0 %, and 2.0 %) over time periods of 15, 30, and 45 days. Remediation progress was monitored using phytotoxicity assessments with radish (Raphanus sativus) root length as a bioindicator, supplemented by urease activity analyses. Notably, the activation process increased the P loading capacity of biochar produced at 450°C, 500°C, and 550°C by 54.6 %, 72.4 %, and 51.8 %, respectively, while reducing the P retention capacity of biochar prepared at 600°C by 31.0 %. The biochar activated at 550°C presented the highest efficiency in remediating Cd-contaminated soils. Key findings indicate that the enhanced specific surface area and oxygenated functional group content of the activated biochar facilitated Cd adsorption and P uptake. The P-loaded biochar exhibited a substantial adsorption capacity for Cd, particularly effective at lower concentrations, rendering it highly suitable for soil remediation purposes. Additionally, the study revealed that the application of biochar led to an increase in soil pH, resulting in precipitation of Cd as hydroxide species and formation of insoluble complexes with phosphate ions, thereby reducing its bioavailability. In summary, incorporating P-loaded biochar into soil significantly improved soil quality and enhanced Cd passivation in contaminated soils. The utilization of biochar produced at 550°C, which exhibited optimal performance, suggests a practical and sustainable approach for soil remediation. Future research endeavors should prioritize the refinement of the biochar production process to enhance cost-effectiveness while maintaining high P loading efficiency.

371. 题目: Adsorption of Se(IV) on kaolinite and montmorillonite in the presence of fulvic acid
文章编号: N24100117
期刊: Applied Geochemistry
作者: Hyeonjin Eun, Seungmo Yeon, Seonggyu Choi, Seokjoo Yoon, Jong-Il Yun
更新时间: 2024-10-01
摘要: This study investigates the influence of fulvic acid, a representative of aquatic natural organic matter (NOM), on the pH-dependent adsorption of Se(IV) on kaolinite and montmorillonite. Given their negative charges in aqueous solutions, Se(IV) and fulvic acid compete for the limited and identical adsorptive sites of clay minerals, particularly in neutral to alkaline environments. This competition was most pronounced under acidic conditions, where both Se(IV) and fulvic acid adsorption are favored. At pH 3, the presence of 20–80 mg·L−1 fulvic acid reduced the Se(IV) adsorption by up to half on both clay adsorbents. However, in near-neutral to alkaline pH regions (pH 6 to 10), the competitive interaction between Se(IV) and fulvic acid was less pronounced, since the adsorption of both fulvic acid and Se(IV) decreased. In particular for kaolinite, a rise in Se(IV) adsorption was evident at lower fulvic acid concentrations (20 mg·L−1). This phenomenon arises from the absence of aqueous complexes between Se(IV) and fulvic acid under acidic conditions, contrasting with their strong interaction under alkaline conditions as observed in the ATR-FTIR spectra. This study sheds light on the influence of NOM on the mobility of Se(IV) in natural waters, an aspect yet to be thoroughly explored.

372. 题目: Photo-transformation of biochar-derived dissolved organic matter and its binding with phenanthrene/9-phenanthrol: The role of functional group and pyrolysis temperature
文章编号: N24100116
期刊: Bioresource Technology
作者: Yifan Niu, Siyao Wang, Peng Gao, Xin Ren, Fangfang Li, Zhanpeng Liu, Lin Wang, Hongbo Peng, Shaohua Ju
更新时间: 2024-10-01
摘要: This study explores the physicochemical attributes of dissolved organic matter from rice straw biochar (BDOM) at varying pyrolysis temperatures and photo-irradiation conditions, focusing on the binding mechanisms of phenanthrene (PHE) and 9-phenanthrol (PTR) using multiple spectroscopic techniques and fluorescence quenching. Following 20 h of photo-irradiation, only 11.3 % of BDOM underwent mineralization, forming new CH3/CH2/CH aliphatics structures. BDOM from biochar produced by pyrolysis at 400°C exhibited a stronger binding affinity with PHE and PTR, achieving 44 % and 52 % maximum binding, respectively. Static and dynamic quenching governed PHE and PTR binding, which was influenced by temperature. Photo-irradiated BDOM showed enhanced binding with PHE, attributed to increased aliphatic content. Hydrogen bond and π-π electron-donor–acceptor (EDA) interactions dominated PTR binding, while π-π interactions and hydrophobic interactions controlled PHE. This study provides valuable insights into BDOM photochemical behaviors and their impact on the environmental fate of polycyclic aromatic hydrocarbons (PAHs) after BDOM photo-irradiation.

373. 题目: Endogenous silicon-activated rice husk biochar prepared for the remediation of cadmium-contaminated soils: Performance and mechanism
文章编号: N24100115
期刊: Environmental Pollution
作者: Tao Lu, Wenzhan Ge, Anyu Li, Shengjun Deng, Tao Min, Guohong Qiu
更新时间: 2024-10-01
摘要: Biochar is widely used for the remediation of heavy metal-contaminated soils. However, pristine biochar generally has limited active functional groups and adsorption sites, thereby exhibiting low immobilization performance for heavy metals. In addition to carbon (C), silicon (Si) is another common macro-element present in rice husk biochar, but it often exists in the form of amorphous oxide and therefore contributes little to the adsorption performance for heavy metals. The transformation of amorphous Si oxide to dissolved silicate through a precipitation effect can significantly improve its heavy metal immobilization capability. Herein, the amorphous Si oxide in rice husk biochar was activated by sodium hydroxide and then the dissolved silicate was immobilized by calcium salt. The as-synthetized Si-activated biochar was used to remediate cadmium (Cd)-contaminated soils. The results indicated that Si-activated rice husk biochar could reduce Cd migration and environmental risks by the transformation from exchangeable Cd into carbonate-bound and residual Cd. With increasing Ca: Si molar ratio, the content of CaCl2 and H2O-extractable Cd exhibited a decreasing trend. Moreover, a higher addition amount of Si-activated biochar improved the Cd immobilization efficiency. The application of 1.0% Ca/Si molar ratio of 2: 2 Si-activated rice husk biochar decreased the CaCl2-Cd and H2O-Cd concentration by a maximum of 83.7% and 90.5% compared with pristine rice husk biochar, respectively. The present work proposes an approach for highly efficient remediation of Cd-polluted soils by biochar.

374. 题目: Better waste utilization: Mg-modified biochar from wetland plant waste for phosphorus removal and carbon sequestration
文章编号: N24100114
期刊: Journal of Environmental Chemical Engineering
作者: Tingting Wang, Xinxi Fu, Yonghua Chen, Jingdong Wu, Yuanyuan Wang, Honghai Wan, Xiangyu Li, Lizhen Zhao
更新时间: 2024-10-01
摘要: Withered wetland plants have become a treat to water ecological security. To address the issue of waste biomass disposal, a typical wetland plant, Hydrocotyle vulgaris, was utilized to produce Mg-modified biochar (MBC) for efficient phosphorus (P) removal and stable carbon sequestration. The adsorption behavior fit Langmuir isotherm and the pseudo second-order kinetic models, which revealed the nature of monolayer chemical adsorption of MBC. The removal of P was achieved through physical diffusion, Mg2+ precipitates, surface complexation and electrostatic attraction. Based on the analysis of thermodynamics models, it can be concluded that the adsorption behavior of P by MBC was spontaneous and endothermic. The MBC exhibited a maximum phosphorus adsorption capacity of 314.048 mg/g. Concurrently, the specific surface area was enhanced from 529.974 m2/g to 931.019 m2/g. The research has also recorded valuable data about the carbon sequestration potential of MBC with the carbon content reaching 0.51 g per g of biochar. It was found from the outcomes that Mg-modified biochar had outstanding carbon sequestration potential and significantly improved P removal efficiency.

375. 题目: Elemental stoichiometry of particulate organic matter across the Atlantic Ocean
文章编号: N24100113
期刊: Biogeosciences
作者: Adam J Fagan, Tatsuro Tanioka, Alyse A Larkin, Jenna A Lee, Nathan S Garcia, Adam C Martiny
更新时间: 2024-10-01
摘要: . Recent studies show that stoichiometric elemental ratios of marine ecosystems are not static at Redfield proportions but vary systematically between biomes. However, the wider Atlantic Ocean is undersampled for particulate organic matter (POM) elemental composition, especially when it comes to phosphorus (i.e., POP). Thus, it is uncertain how environmental variation in this region translates into shifts in the C:N:P ratio. To address this, we analyzed hydrography, genomics, and POM concentrations from 877 stations on the meridional transects AMT28 and C13.5, spanning the Atlantic Ocean. We observed nutrient-replete, high-latitude ecosystem C:N:P to be significantly lower than that in the oligotrophic gyres. Latitudinal and zonal differences in elemental stoichiometry were linked to overall nutrient supply as well as N vs. P stress. C:P and N:P were generally higher in the P-stressed northern region compared to Southern Hemisphere regions. We also detected a zonal difference linked to a westward deepening nutricline and a shift from N to P stress. We also evaluated possible seasonal changes in C:N:P across the basin and predicted these to be limited. Overall, this study confirms latitudinal shifts in surface ocean POM ratios but reveals previously unrecognized hemisphere and zonal gradients. This work demonstrates the importance of understanding how regional shifts in hydrography and type of nutrient stress shape the coupling between Atlantic Ocean nutrient and carbon cycles.

376. 题目: A novel strategy employing lignin biochar to simultaneously promote remediation and safe crop production in Cd-contaminated soil
文章编号: N24100112
期刊: Chemical Engineering Journal
作者: Yanying He, Baobin Mi, Cheng Luo, Honglin Tao, Xin Zhang, Jinwen Yu, Xueying Mo, Jian Hu, Long Chen, Naimei Tu, Fangfang Wu
更新时间: 2024-10-01
摘要: The scarcity of arable land and the problem of food security urgently called for a strategy of Remediation-by-Production (RBP). Biochar is a promising method for addressing Cd-contaminated soils, but the time required for remediation and the variability of long-term performance have a direct impact on the realization of the RBP strategy. We have developed a novel approach for remediating cadmium-contaminated flooded soil by utilizing lignin biochar (LBC) in combination with safe rice cultivation. The addition of 1 % LBC achieves efficient Cd passivation (CP: 90.89 %) before rice Cd uptake peaks. Meanwhile, LBC can increase soil organic matter and alter microbial community structure, decreasing the relative abundance of soil pathogenic bacteria from 5.12 % to 4.03 % while raising nutritional bacteria from 15.18 % to 28.82 %. Furthermore, LBC successfully reduced the accumulation of Cd in rice grains by 31.3 % ∼ 54.6 %, making rice dwarf, sturdy, and greener, and lowering the health risk coefficients of Cd across various age groups by Monte Carlo simulations. This study elucidated the critical role of humic substances of LBC in remediation time and performance and laid a solid theoretical foundation for promoting the application of biochar in soil contamination remediation and simultaneously realizing the safe production of crops.

377. 题目: The fate of cadmium during ferrihydrite phase transformation affected by dissolved organic matter: Insights from organic-mineral interaction
文章编号: N24100111
期刊: Chemical Geology
作者: Xiaofan Pan, Xin Huang, Ning Deng
更新时间: 2024-10-01
摘要: Ferrihydrite (Fh) is an important scavenger for sequestering cadmium (Cd). However, Fh is poorly crystallized and tends to undergo phase transformation under the impact of dissolved organic matter (DOM). The roles of DOM in Fh transformation pathway and the consequent Cd2+ remobilization behavior remain debate due to its structural heterogeneity and diversity. Herein, formic acid (FA), oxalic acid (Ox), and citric acid (CA) were selected as model DOM, which have one, two, and three carboxyl ligands, respectively. Fe K-edge extended X-ray absorption fine structure (EXAFS) spectra revealed an organic-specific correlation between Fh transformation and Cd2+ transport. FA with monodentate carboxyl ligand, lacking binding with Fh particles, had negligible influence on transformation dynamics and Cd2+ transport. The complexation of bidentate Ox with Fh particles impaired the stability of Fe(O,OH)6 octahedra, accelerating Fh phase transformation, thereby increasing Cd2+ release. During the subsequent recrystallization, Ox guided crystal growth via oriented attachment, which possibly occluded the remaining Cd2+ within structural defects of the secondary minerals. Conversely, tridentate CA exhibited a strong affinity with Fh, resulting in the formation of ferric citrate surface complexes that stabilized Fh against transformation and thus enhanced the long-term immobilization of Cd2+. These findings highlight the significant role of organic-ion/mineral interactions in Fh transformation, which are fundamentally linked to predicting Cd2+ transport behavior in environmental systems.

378. 题目: Explore synergistic catalytic ozonation by dual active sites of oxygen vacancies and defects in MgO/biochar for atrazine degradation
文章编号: N24100110
期刊: Journal of Environmental Chemical Engineering
作者: Shiwen Dong, Luzhen Liu, Wen Xu, Haijun Cheng, Zhiqiao He, Feilong Dong, Da Wang, Lizhang Wang, Shuang Song, Jun Ma
更新时间: 2024-10-01
摘要: The design of highly efficient and sustainable catalytic materials is highly desirable for the development of advanced oxidation process (AOPs) used in water treatment. This study used waste litchi shells as precursors to prepare biochar (BC). The composite material (BC@MgO) was synthesized upon loading magnesium oxide (MgO) on BC and used for the heterogeneous catalytic ozonation (HCO) of atrazine (ATZ). BC@MgO exhibited an ATZ degradation rate of 92.8 % over 30 min under the optimal degradation conditions and maintained its good catalytic performance over four cycles, exhibiting excellent catalytic activity and stability. Characterization and experimental results revealed the synergistic effect of oxygen vacancies (OVs) and BC defects on the adsorption and decomposition of ozone molecules. The exposure of the surface magnesium ions was promoted in the presence of OVs on MgO, allowing water molecules to dissociate on the surface magnesium sites to form surface hydrated hydroxyl groups. Biochar defects accelerated the adsorption of ozone molecules by virtue of its higher surface energy. These active sites led to the substantial generation of reactive oxygen species (ROS), which possessed strong oxidizing ability and thereby participated in the degradation of ATZ. In addition, the possible degradation pathways and toxicity of ATZ were evaluated. Overall, this design provided a novel approach to the comprehensive utilization of waste lychee shells, as well as an efficient, stable, and green catalyst for the development of AOPs used in water treatment.

379. 题目: Tracking suspended particulate organic matter biochemistry from glacial meltwater runoff to coastal waters of an Antarctic fjord
文章编号: N24100109
期刊: Marine Chemistry
作者: Claudia Parodi, Luis Cerpa, Zhuoyi Zhu, Jing Zhang, Pablo Muniz, Natalia Venturini
更新时间: 2024-10-01
摘要: Increased glacier melting runoff in Antarctica involves intensification of freshwater, nutrients, sediments and organic matter inputs from land to the sea, which is impacting coastal ecosystems. Basic environmental characteristics of water and biochemical composition of suspended particulate organic matter (POM) both in the proglacial melting runoff system (PROGLARS) of Collins Glacier and marine surface waters of Collins Bay was studied based on organic biopolymers and molecular level analysis of amino acids (AAs), to discern among sources and degradation state in the two environments. Hierarchical Clustering Analysis revealed that PROGLARS stations and marine stations form two distinct groups in terms of water physicochemical characteristics and suspended POM biochemical composition. These differences are the consequence of low restricted contribution of freshwater from Collins Glacier runoff into the coastal-marine environment. Our results evidenced low concentrations of terrestrial suspended POM in marine waters of Collins Bay mainly attributed to low meltwater inputs between the 1st and 7th of February 2018. In terms of macromolecular composition, the predominance of proteins, denote the labile nature of suspended POM in the two environments. Suspended POM in Collins Bay is labile, poorly degraded, representing a protein supplemented food resource, with high energetic value and easily assimilated by heterotrophic marine organism. AAs composition supported less degraded suspended POM derived from marine phytoplankton in surface waters of Collins Bay, whereas, great degradation of suspended POM in the proglacial runoff system of Collins Glacier. Changes in the biochemistry of suspended POM caused by glacial melting and retreat, may affect food features and availability, the productivity of ecosystems, and ultimately, the capacity of Antarctic fjords to act as carbon sinks and climate regulators. Considering low influence of Collins Glacier meltwater in coastal marine waters of Collins Bay, due to the relatively slow retreat of Collins Glacier and low development of its meltwater runoff system, the results of our work are relevant as baseline information for comparison with other Antarctic fjords. Further knowledge about meltwater runoff and suspended POM input dynamics in Antarctic coastal ecosystems, is critical, particularly in areas prone to undergo increased glacier melting in the following decades.

380. 题目: Mn and P co-doped biochar catalyst for persulfate efficient degradation of tetracycline hydrochloride:Process and mechanism
文章编号: N24100108
期刊: Journal of Environmental Chemical Engineering
作者: Xiangyu Fu, Yafeng Li, Keqing Cui, Yihan Liu, Le Lv
更新时间: 2024-10-01
摘要: A novel manganese/phosphorus-doped biochar (Mn/P-C) catalyst was prepared for the degradation of tetracycline hydrochloride (TCH) by activating peroxymonosulfate (PMS). Characterization of the catalyst revealed that Mn/P-C possessed stacked, complex pleated sheets and surface oxygen-containing functional groups, providing abundant active sites. Mn/P-C exhibited superior adsorption and catalytic properties. Nearly complete removal of TCH was achieved under optimal conditions: a PMS concentration of 2 mM, pH 6.51, and catalyst dosage of 0.5 g/L within 120 minutes of reaction time. The reaction rate constant of the system was 0.060 min−1, which was 13.79 times higher than that of pure biochar. XPS characterization before and after the reaction, quenching experiment, and electron paramagnetic resonance (EPR) experiment comprehensively verified the reaction pathway mechanisms. The primary radicals involved were SO4•- and O2•-, while the 1O2 non-radical transfer pathway was also generated on the catalyst surface, enhancing electron transfer and accelerating catalytic degradation. UPLC-MS/MS was used to investigate the main degradation intermediates and the possible transformation pathways were proposed. The toxicity of TCH and its intermediates was evaluated by the quantitative structure-activity relationship (QSAR) method. Theoretical calculations provided deeper insights into TCH degradation pathways through DFT computational analysis. This study confirms that doping biochar with transition metals and nonmetals can synergistically enhance the degradation efficacy of PMS-activated biochar catalysts, providing a novel approach for the application of carbon-based material catalysts in persulfate activation.

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