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141. 题目: Adsorption of fulvic acid onto polyamide 6 microplastics: influencing factors, kinetics modeling, site energy distribution and interaction mechanisms
文章编号: N21011412
期刊: Chemosphere
作者: Shuai Tang, Lujian Lin, Xuesong Wang, Xuan Sun, Anqi Yu
更新时间: 2021-01-14
摘要: Information on the interactions of microplastics (MPs) with dissolved organic matter (DOM) is essential for understanding their environmental impacts. This study selected fulvic acid (FA) as a typical DOM to investigate the influence of contact time, temperature, dosage, solution pH, salinity, and coexisting metal ions on the adsorption of FA onto polyamide 6 (PA6) MPs. The adsorption kinetic and isotherm can be successfully described by mixed-order (MO) and Freundlich models. The adsorption site energy distribution based on the Freundlich equation was applied to analyze the interaction between FA and PA6-MPs and the adsorption site heterogeneity. Thermodynamic analysis demonstrated that the values of parameters (ΔGads°, ΔSads°, ΔHads°) were significantly affected by initial solution concentrations and the adsorption process was spontaneous, endothermic, and randomness-increased. Fourier transform-infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) revealed the importance of amide functional groups of PA6-MPs in controlling FA adsorption. Hydrogen bonds, hydrophobic, electrostatic, and n-π electron donor-acceptor (n-π EDA) interactions played different roles on adsorption of FA under different conditions of solution chemistry. These findings are beneficial to provide new insights involving the adsorption behavior and interaction mechanisms of FA onto PA6-MPs for the environmental risk assessment of MPs.

142. 题目: Assessment of organic carbon migration and biofilm formation potential on polymeric tubes in contact with water
文章编号: N21011411
期刊: Journal of Hazardous Materials
作者: Thi Huyen Duong, Ji Won Park, Sung Kyu Maeng
更新时间: 2021-01-14
摘要: Biofilm formation has been frequently identified as a pathway of nosocomial infection in polymeric tubes used for patients of all ages. Biofilm formation on tube surfaces can lead to hygienic failure and cause diarrhea, stomach pain, inflammation, and digestive system disease. This study investigated the influence of polymeric tube materials in contact with water on the biomass formation potential and migration potential of microbially available carbon from plasticizers using a BioMig test. The thermoplastic elastomer tube, which is reusable, leached a relatively low amount of assimilable organic carbon to water. In contrast, the assimilable organic carbon migration potential of polyurethane was the most significant, 6-fold greater than that of the thermoplastic elastomer. Moreover, the same materials (e.g., silicone) produced via different manufacturing processes showed significant differences in migration behaviors. The potential biomass formation observed in polyurethane was approximately 7 × 109 cells cm-2 for both Aeromonas hydrophila and Escherichia coli strains. This study highlights the importance of choosing the correct material characteristics of polymeric tubes in contact with water to protect them from bacterial contamination. Therefore, manufacturers can use the BioMig test to evaluate and produce more hygienic and biostable tubes.

143. 题目: Sequential presence of heavy metal resistant fungal communities influenced by biochar amendment in the poultry manure composting process
文章编号: N21011410
期刊: Journal of Cleaner Production
作者: Sanjeev Kumar Awasthi, Yumin Duan, Tao Liu, Yuwen Zhou, Shiyi Qin, Huimin Liu, Sunita Varjani, Mukesh Kumar Awasthi, Zengqiang Zhang, Ashok Pandey, Mohammad J. Taherzadeh
更新时间: 2021-01-14
摘要: In this study, we investigated the influence of coconut shell biochar (CSB) on heavy metal resistance fungi (HMRF) during poultry manure (PM) composting by 18S rDNA Internal Transcribed Spacer Amplicon Sequencing analysis. Five different concentrations of CSB (2.5%, 5%, 7.5%, and 10% dry weights basis) were applied with a mixture of PM and wheat straw (5:1 ratio dry weight basis) and without CSB (CK) was used as control. The results showed that sequence number rose along with increasing CSB concentration but total relative abundance (RA) of HMRF decreased 56.33%, 74.65% in T4 and T5, respectively. However, greater RA of HMRF was found in T1 or without biochar applied treatment. The phylum of Basidiomycota was the dominant fungal community accounting for 61.14%, 6.16%, 32.18%, 74.65%, and 73.73% from T1 to T5 of the total fungi abundance, with wide presence of the Wallemiomycetes and Eurotiomycetes classes. The Wallemia and Aspergillus were the richest genus and species. Wallemia_sebi, Altemaria_alternata and Aspergillus_amoenus were detected having greater abundance among all treatments. Besides this, the network correlation pattern confirmed that the relative greater percentage of correlation among dominant HMRF community with bio-available HM and other physicochemical factors increased with the addition of biochar. There was reasonable infer that the biochar amendment in composting could constitute favorable habitat for an active fungal population.

144. 题目: Biochar affects silicification patterns and physical traits of rice leaves cultivated in a desilicated soil (Ferric Lixisol)
文章编号: N21011409
期刊: Plant and Soil
作者: Felix de Tombeur, Julia Cooke, Laurie Collard, Drissa Cisse, Fatimata Saba, David Lefebvre, Victor Burgeon, Hassan Bismarck Nacro, Jean-Thomas Cornelis
更新时间: 2021-01-14
摘要: Increasing the leaf silicification of cereal crops to ameliorate defenses against stresses and improve yields constitutes a major challenge in (sub-)tropical regions with highly desilicated soils. We tested the efficacy of different biochars – as readily available alternatives to commercial fertilizers – to increase leaf silicification and understand subsequent impacts of leaf traits that might benefit crops.

145. 题目: UV/H2O2-assisted forward osmosis system for extended filtration, alleviated fouling, and low-strength landfill leachate concentrate
文章编号: N21011408
期刊: Journal of Membrane Science
作者: Bilal Aftab, Jinwoo Cho, Jin Hur
更新时间: 2021-01-14
摘要: The forward osmosis (FO) membrane process is a good option for treating complex wastewater, such as landfill leachate, owing to its high rejection. However, organic membrane fouling and the generation of high-strength concentrate hamper efficient and environmentally friendly operation. To overcome these limitations, an integrated FO system combined with UV/H2O2 oxidation is proposed in this paper. Changes in the heterogeneous organic composition of the leachate were tracked along the treatment processes via size exclusion chromatography and excitation emission matrix combined with parallel factor analysis, which allowed us to pinpoint the organic fractions responsible for FO membrane fouling and evaluate their removal efficiency. Three fluorescent components, including tryptophan-like (C1), fulvic-like (C2), and humic-like (C3) components, were identified in the landfill leachate. A separate UV/H2O2 oxidation system led to selective removal of the organic leachate fractions, causing membrane fouling by ∼80% along with the overall removal of bulk leachate by ∼45%. Compared to traditional FO, the integrated system resulted in improved filtered volume (by 40%), decreased overall membrane resistance (by 30%), complete flux recovery after physical cleaning, and 50% reduction of organic carbon in the membrane concentrate. Moreover, the concentrate from the integrated FO system was characterized by a much lower abundance of large molecules, which is beneficial for the reclamation of concentrate due to its high biodegradability. This study demonstrated the effectiveness of UV/H2O2 oxidation as an integrated option for an FO system used for extended filtration, membrane fouling mitigation, and the production of low-strength landfill leachate concentrate.

146. 题目: Enrichment of soil organic carbon in the eroded sediments due to the simultaneous occurrence of rain and wind
文章编号: N21011407
期刊: Geoderma
作者: Majid Mahmoodabadi, Samira Zamani, Najme Yazdanpanah
更新时间: 2021-01-14
摘要: Study of the simultaneous effect of wind and rain is of great importance in the environmental studies of erosion for more accurate measurement and modeling of soil loss. There is little information on the combined effects of rain and wind on soil erosion as well as soil organic carbon (SOC) loss. The purpose of this study was to investigate interrill erosion in relation to SOC loss and enrichment ratio (ERoc) as influenced by rain intensity and wind velocity linking to flow hydraulic characteristics. Three rain intensities of 20, 40 and 60 mm h−1 and four wind velocities of 0, 6, 9 and 12 m s−1 were generated on three different soil samples (sandy, sandy loam and loam), each at three replicates (totally 108 runs). The SOC loss was determined through the concentration of organic carbon in sediment and the measured sediment load. The values of SOC loss and ERoc ranged from 0.04 to 4.04 mg m−1 s−1 and from 0.52 to 9.40, respectively. The measured interrill erosion rates and SOC losses increased at higher wind velocities and rain intensities, especially when wind velocity became more than a threshold value of 9 m s−1. For each soil, a direct linear relationship was distinguished between the losses of soil and SOC. Accordingly, SOC loss accounted for 0.36%, 0.17%, and 2.19% of the total soil loss in the sandy, sandy loam and loam soils, respectively. The ERoc was nearly constant for each soil and not changed with the increased soil erosion rate. Finally, flow velocity and unit stream power were found as the best predictors of soil and SOC losses in a wind-driven interrill erosion system.

147. 题目: Short- and long-term effects of animal manures and mineral fertilizer on carbon stocks in subtropical soil under no-tillage
文章编号: N21011406
期刊: Geoderma
作者: Lucas Antonio Telles Rodrigues, Sandro José Giacomini, Celso Aita, Cledimar Rogério Lourenzi, Gustavo Brunetto, Alessandra Bacca, Carlos Alberto Ceretta
更新时间: 2021-01-14
摘要: Establishing the long-term effects of different types of animal manures on soil organic carbon (SOC) stocks has both agronomic and environmental implications. However, only a few studies have analyzed the effects of the types of animal manure on SOC storage in subsurface soil layers. Furthermore, the effect of animal manure on labile and stable soil organic matter (SOM) fractions has been scarcely reported for subtropical no-till soils. We evaluated the effect of animal manure application in the short and long term (4 and 12 years) on SOC storage at different depths throughout a 0–70 cm soil profile and on the physical fractions of SOM in the 0–20 cm layer of a sandy Alfisol cropped under no-tillage. The study involved five treatments: pig deep-litter (PDL), cattle slurry (CS), pig slurry (PS), mineral fertilizer (MF) and a control without fertilization (CL). The SOC stock in the soil profile (0–70 cm) was influenced by manure application in only the long term, which was due to high SOC accumulation in the surface (0–20 cm) in the short-and long-term. The PDL and CS applications resulted in 16% (8.6 Mg ha−1) and 10% (5.2 Mg ha−1) increases in the SOC stock, respectively, compared with those in the CL, but only PDL resulted in greater SOC stocks than MF. These results are related to the greater C addition and higher SOC retention coefficient with the PDL application (17%) than with the CS (15%) and PS (7%) applications. Most of the manure-induced changes were observed in the silt plus clay-sized heavy fraction (SCHF), with PDL and CS being more efficient at increasing SOC storage as organic-mineral complexes than PS or MF in the 0–20 cm soil layer. However, in the subsurface layer (20–70 cm), manure caused a decrease in SOC compared with that in the CL, resulting in negative SOC storage rates in this layer, which partially or completely neutralized the SOC storage rates observed in the surface layer (0–20 cm). In the long term, this condition resulted in SOC storage rates in the 0–70 cm soil profile of 0.48 Mg ha−1 year−1 for PDL, 0.21 Mg ha−1 year−1 for CS, −0.03 Mg ha−1 year−1 for PS and 0.01 Mg ha−1 year−1 for MF. These results indicate that PDL and CS are suitable alternatives to MF for increasing the SOC stock and that the SOC retention is greater with solid manure than with liquid manure (PDL vs CS and PS) and with CS than with PS. Moreover, the results reveal the importance of monitoring SOC changes in the long term and within deep soil layers to better quantify the effects of successive applications of animal manure on SOC storage potential in subtropical sandy soils under no-tillage.

148. 题目: Photo transformation of 5-methylbenzotriazole and 5-chlorobenzotriazole by UV irradiation: Influences of pH, salinity, metal species and humic acid
文章编号: N21011405
期刊: Environmental Research
作者: You-Sheng Liu, Yu-Xiao Cheng, Dan Wu, Quan-Le Chen, Guang-Guo Ying
更新时间: 2021-01-14
摘要: 5-methylbenzotriazole (5-TTri) and 5-chlorobenzotriazole (CBT) are two benzotriazole derivatives widely used in various industrial and domestic applications. This paper reports on the photochemical behaviour of 5-TTri and CBT in aqueous solutions under UV radiation at 254 nm and the influences of pH, salinity, metal species and humic acid (HA) on their photo-transformation processes. The photolysis of 5-TTri and CBT under the exposure to UV light were found to follow the first-order reaction kinetic in all cases with half-lives ranging from 7.1 h to 24.3 h for 5-TTri and 5.1 h–20.5 h for CBT in various aqueous solutions containing metal ions and HA. The photolysis rates for both 5-TTri and CBT were strongly dependent on the solution pH value, and decreased with increasing solution pH. Salinity, metal species Cu2+ and Fe3+, and especially HA had inhibitory effects on the photolysis of 5-TTri and CBT under UV light irradiation at 254 nm. We proposed the tentative photo transformation schemes for both 5-TTri and CBT, which involved two photoproducts (4-methylaniline and N, N-diethylaniline- p-toluidine) and three photoproducts (4-chloroaniline, Aniline and 2,6-diethylaniline), respectively, via N–N and N–NH bond scission and dechlorination process.

149. 题目: Dynamic variations of dissolved organic matter from treated wastewater effluent in the receiving water: Photo- and bio-degradation kinetics and its environmental implications
文章编号: N21011404
期刊: Environmental Research
作者: Yulai Wang, Yue Gao, Tianran Ye, Yunyun Hu, Changming Yang
更新时间: 2021-01-14
摘要: Dissolved effluent organic matter (dEfOM) from wastewater treatment plants (WWTPs) is bound to encounter photo- and bio-degradation as discharged into the receiving water body. However, the comprehensive variations of dEfOM by photo- and bio-degradation are not well unveiled because of its compositional heterogeneity. In this work, dissolved organic carbon (DOC) concentrations, UV–Vis and fluorescent spectra combined with fluorescence regional integration (FRI) analysis were used to investigate the changes in bulk dEfOM and its fluorescent components during photo- and bio-degradation processes in the receiving water body. Results showed that 48.49%–69.62% of the discharged dEfOM was decomposed by ultra violet (UV)-irradiation and indigenous microbes, while the others (33%–45%) were recalcitrant and stable in the receiving water body. Specifically, the photo- and bio-degradation of chromophoric, fluorescent dEfOM and its components were found to follow the single or double exponential kinetic model, and the differences in photo- and bio-degradability of each components shifted its composition. Furthermore, results of bio-degradation after UV-irradiated dEfOM indicated that there was overlapping of photo- and bio-degradable fractions in dEfOM, and photoreactions could improve the self-production of natural organic matter in the receiving water body. These results could improve the understanding the fate of discharged dEfOM in the receiving water body, and we proposed some cost-effective strategies for discharging WWTPs effluent.

150. 题目: Effects of phosphorus modified nZVI-biochar composite on emission of greenhouse gases and changes of microbial community in soil
文章编号: N21011403
期刊: Environmental Pollution
作者: Zhihui Liu, Jingchun Tang, Xinwei Ren, Sean M. Schaeffer
更新时间: 2021-01-14
摘要: The effect of modified biochar on the greenhouse gas emission in soil is not clear until now. In this study, biochar (BC) was modified by phosphoric acid (P) and further combined with nano-zero-valent iron (nZVI) to form nZVI-P-BC composite. The P modified biochar could significantly increase the available phosphorus in soil. The release of CO2 and N2O in soil was inhibited during the initial stage of the experiment, with inhibition becoming more obvious over time. On the contrary, CH4 and N2O emission in soil was enhanced by nZVI-P-BC composite. The proportion of Sphingomonas and Gemmatimonas were the most abundant bacterial species, which were related to the metabolism and transformation of nitrogen. The community structure of the fungus was also affected by nZVI-P-BC composite with Fusarium as the main species. PCoA analysis result suggested that bacterial community was more affected by the incubation time while fungal community was more related to the addition of different biochar and modified biochars.

151. 题目: Contribution of phenanthrene in different binding sites to its biodegradation in biochar-amended soils
文章编号: N21011402
期刊: Environmental Pollution
作者: Zheng Ding, Jianjun Huang, Jie Chi
更新时间: 2021-01-14
摘要: Biochars can strongly sorb hydrophobic organic contaminants in soils. However, contribution of contaminants in different binding sites to their biodegradation in biochar-amended soils is not clear. In this work, wheat straw biochars were prepared at pyrolysis temperatures of 400 °C (BC400) and 700 °C (BC700). During a 42-day experiment, degradation rate constant of phenanthrene in soils was in the order of treatment without biochar (1.64 × 10-2 d-1) > treatment with BC700 (0.96 × 10-2 d-1) > treatment with BC400 (0.30 × 10-2 d-1). At the beginning, amendment of BC400 and BC700 reduced the rapidly desorbing fraction of phenanthrene in soils by 44.8% and 92.5%, respectively. At the end, both phenanthrene and microbial biomass highly concentrated on the biochar separated from soils. The results of a coupled model of desorption and biodegradation revealed that only phenanthrene in rapidly desorbing sites was degraded in BC400-amended soils, whereas degradation of phenanthrene in both rapidly and slowly desorbing sites occurred in BC700-amended soils, contributing 24.4% and 75.6% of the degradation, respectively. High fraction (>95%) of biodegradable phenanthrene in slowly desorbing sites was the key reason for higher biodegradation rate of phenanthrene in soils with BC700 than in soils with BC400.

152. 题目: Coupling Experiments with Calculations to Understand the Thermodynamics Evolution for the Sorption of Zwitterionic Ciprofloxacin on Oxidizing-Aged Pyrogenetic Chars in the aquatic system
文章编号: N21011401
期刊: Journal of Hazardous Materials
作者: Shishu Zhu, Pan Wang, Xiao-bao Yang, Chao Jin, Rongliang Qiu
更新时间: 2021-01-14
摘要: Oxidized aging due to the long-term exposure can significantly alter the sorption of pyrogenetic chars (i.e., biochar, BC) towards antibiotics, which determined their fates in natural environments. In this study, the sorption of ciprofloxacin (CIP) on the oxidizing-aged BCs was studied linking the experimental thermodynamics and theoretical calculations. Results revealed that Q0 of CIP negatively correlated with their average site energies (Em), while pore-normalized Q0 on aged BCs were 2-6 folds higher than fresh BCs. From competitive sorption, it is proposed that the transformation of CIP± to CIP+ occurred and the π+-π electron donor-acceptor interaction and Coulombic attraction onto the aged BCs played a critical role. These two specific interactions with CIP were thermodynamically improved when aging degree increased and favored the free energies (ΔaG) of sorption by 2-5 kJ mol-1. Based on the identified relationship between experimental ΔOA-ΔG0 with Ea through DFT calculations, the contributions of the specific interactions to antibiotic sorption on aged BCs were quantified. This study provided an in-depth understanding of how the aging process affects the sorption of zwitterionic antibiotics on BCs and also possibilities to predict the fate of antibiotics in the presence of BCs over a long-term period.

153. 题目: Differences in phenolics produced by invasive Quercus rubra and native plant communities induced changes in soil microbial properties and enzymatic activity
文章编号: N21011310
期刊: Forest Ecology and Management
作者: Małgorzata Stanek, Szymon Zubek, Anna M. Stefanowicz
更新时间: 2021-01-13
摘要: Invasive trees can alter soil properties and ecosystem functioning by producing phenolic compounds. Phenolics can influence carbon and nitrogen availability as well as enzymatic activity or act as signaling molecules. In plant-microorganism interactions, species-specific phenolics can be the source of food or toxicity. They may have antimicrobial, stimulatory or both (ambiguous) properties and thus affect soil microbial properties, enzymatic activity, and plant-soil feedbacks differently. We hypothesized that phenolic compounds with antimicrobial properties produced by invasive Quercus rubra would reduce soil microbial biomass and enzymatic activity, and alter microbial community structure. We expected these changes to be most pronounced in the soil organic horizon as they are driven by litter chemistry. We tested changes, potentially associated with the concentrations of 12 phenolic compounds in Q. rubra litter and soil, in microbial properties (respiration rate, bacterial and fungal biomass), enzymatic activity, and microbial community structure in organic and mineral soil horizons as well as in arbuscular mycorrhizal fungi (AMF) spore number and species richness in mineral soil horizon. We found that Q. rubra reduced several soil parameters, namely respiration rate, phosphatase activity, total microbial biomass, bacterial (both G + and G–) biomass, and 16:1ω5 NLFA AMF storage lipid marker as well as changed microbial community structure, which supports our hypothesis that the phenolics produced by Q. rubra have mostly toxic effect on native soil communities. However, Q. rubra did not affect arylsulfatase and urease activity, saprotrophic fungi population, and the number of AMF spores and species. The changes in soil microbial properties and enzymatic activity may be related to high amounts of ellagic acid, ferulic acid, phloridzin, and syringic acid provided with newly shed Q. rubra litter to the soil surface. Some phenolics found in soil, i.e., phloridzin and (–)-epicatechin, correlated negatively, while others, i.e., quercetin and chlorogenic acid, correlated positively with soil microbial parameters and/or enzymatic activity, which suggest either antimicrobial or stimulatory properties of these compounds. Our study demonstrated that invasive Q. rubra has multiple potential effects on soil microbial communities, which can mediate plant-soil feedbacks. Future research should address the long-term consequences of these changes for forest ecosystems and the fitness of native flora.

154. 题目: Effects of understory removal and thinning on soil aggregation, and organic carbon distribution in Pinus massoniana plantations in the three Gorges Reservoir area
文章编号: N21011309
期刊: Ecological Indicators
作者: Yafei Shen, Ruimei Cheng, Wenfa Xiao, Shao Yang
更新时间: 2021-01-13
摘要: Forest ecosystems are characterized by the largest terrestrial carbon (C) stocks, play a vital role in global C cycle. Numerous previous studies have documented soil C accumulation and its related contributory factors, and have highlighted the soil physical structure, particularly soil aggregates, as a potential key factor determining the accumulation of C in grasslands or farmlands. At present, however, comparatively little is known regarding the soil aggregation and organic C distribution in plantations following forest management. In this study, we sought to identify the effects of forest management on soil aggregation and organic C distribution in Pinus massoniana plantations in the Three Gorges Reservoir area of China. To this end, we compared soil water-stable aggregates (WSAs), organic C distribution, and organic C chemical composition in the 0–10 cm soil layer of forest plots subjected to the following four treatments: unmanaged intact forest (control: CK), low-intensity thinning (15% thinning: LIT), high-intensity thinning (70% thinning: HIT), and understory removal (all understory shrubs removed: SR). The results indicated that the plantation soil was clearly characterized by macroaggregate and microaggregate structures. Among the WSAs, aggregates ranging in size from 250 to 2000 µm had the highest weight proportion (46.78%–53.87%), whereas silt plus clay-sized particles (<53 μm) had the smallest proportion (2.99% to 5.91%). For all treatment plots, soil organic carbon (SOC) was mainly distributed in macroaggregates (approximately 80%). The macroaggregates were significantly lower under SR and HIT treatments than those in CK treatments (p < 0.05). In the SR and thinning treatments (LIT and HIT), the content of aggregate-associated C was significantly reduced compared with that in the CK treatment (p < 0.05), whereas the total SOC content significantly decreased only in HIT treatment. We also found that the HIT treatment had the effect of altering soil structure, reducing the relative stability of surface SOC, and enhancing microbial respiration, thereby influencing the soil C storage capacity of P. massoniana plantation soils. These findings will provide a useful reference for reducing soil CO2 emissions under global warming and developing sustainable plantation management strategies in the Three Gorges Reservoir area.

155. 题目: Molecular weight-dependent abundance, absorption, and fluorescence characteristics of water-soluble organic matter in atmospheric aerosols
文章编号: N21011308
期刊: Atmospheric Environment
作者: Xingjun Fan, Feng Cai, Cuncun Xu, Xufang Yu, Yan Wang, Xin Xiao, Wenchao Ji, Tao Cao, Jianzhong Song, Ping'an Peng
更新时间: 2021-01-13
摘要: Water-soluble organic matter (WSOM) plays a significant role in solar radiative forcing and atmospheric chemistry. Its chemical composition and properties are highly molecular weight (MW)-dependent, but are still poorly understood. In this study, 10 PM2.5 samples were collected at a rural site in China, and the WSOM therein was fractionated into three MW fractions, >5 kDa (F1), 1–5 kDa (F2), and <1 kDa (F3), using an ultrafiltration (UF) system. The abundance, optical properties, and fluorescence properties of the three MW fractions were comprehensively determined using a total organic carbon (TOC) analyzer, ultraviolet–visible (UV–vis) spectroscopy, and excitation-emission matrix (EEM) fluorescence spectroscopy combined with parallel factor (PARAFAC) modeling. The proportional TOC and Abs365 distributions of the MW fractions were F1:F2:F3 ≈ 24:22:54 and 40:24:36, respectively. This suggested that the major OC species in bulk WSOM were partitioned into the low MW (<1 kDa) fraction, while the major light-absorbing chromophores were partitioned into the large MW (F1 + F2, >1 kDa) fraction, and were especially prevalent in the >5 kDa fraction. The optical parameters, i.e., SUVA254 and MAE365, generally increased with the apparent increase in MW, suggesting that the higher MW fractions might have a stronger aromaticity and light absorption capacity. The EEM-PARAFAC analysis identified three humic-like substances (HULIS) (C1–C3) and one protein-like (C4) substance for all MW fractions, of which the proportional distributions were observed as C1:C2:C3:C4 ≈ 20:24:41:15, 21:23:44:12, and 41:22:13:24 for F1, F2, and F3, respectively. This indicated that the >1 kDa fraction was enriched in highly-oxygenated HULIS (C3), whereas the <1 kDa fraction had more less-oxygenated HULIS (C1) and protein-like (C4) substances than the >1 kDa fraction. The study provided a detailed insight of the MW-dependent characteristics of WSOM by reducing their heterogeneity and complexity, which is of great significance for further understanding the chemical properties and structures of WSOM.

156. 题目: Sorption of brilliant green dye using soybean straw-derived biochar: characterization, kinetics, thermodynamics and toxicity studies
文章编号: N21011307
期刊: Environmental Geochemistry and Health
作者: Govind Vyavahare, Ranjit Gurav, Ravishankar Patil, Shubham Sutar, Pooja Jadhav, Devashree Patil, Yung-Hun Yang, Jingchun Tang, Chetan Chavan, Sangeeta Kale, Jyoti Jadhav
更新时间: 2021-01-13
摘要: The present study was aimed to investigate brilliant green (BG) dye sorption onto soybean straw biochar (SSB) prepared at 800 °C and further understanding the sorption mechanism. Sorption kinetic models such as pseudo-first and pseudo-second order were executed for demonstrating sorption mechanism between the dye and biochar. Results of kinetics study were fitted well to pseudo-second-order kinetic model (R2 0.997) indicating that the reaction followed chemisorption mechanism. Furthermore, the effect of various parameters like sorbent dose, dye concentration, incubation time, pH and temperature on dye sorption was also studied. The maximum dye removal percentage and sorption capacity for SSB (800 °C) within 60 min were found to be 99.73% and 73.50 mg g− 1, respectively, at pH 8 and 60 °C temperature, whereas adsorption isotherm studies showed a higher correlation coefficient values for Freundlich model (R2 0.990–0.996) followed by Langmuir model suggesting that sorption process was multilayer. The characterization of biomass and biochar was performed with the aid of analytical techniques like scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) theory, X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA). FTIR analysis showed active groups on biochar surface. BET study revealed higher surface area of biochar (194.7 m2/g) than the biomass (12.84 m2/g). Besides, phyto- and cytogenotoxic studies revealed significant decrease in the toxicity of dye containing water after treating with SSB. Therefore, this study has proved the sorption potential of soybean straw biochar for BG dye and could be further considered as sustainable cost-effective strategy for treating the textile dye-contaminated wastewater.

157. 题目: The C/N ratio and phenolic groups of exogenous dissolved organic matter together as an indicator for evaluating the stability of mineral-organic associations in red soil
文章编号: N21011306
期刊: Journal of Soils and Sediments
作者: Xiaojia Zhang, Yanan Wang, Jiong Wen, Yang Zhang, Shiming Su, Yunjie Wen, Mengmeng Yan, Lingyu Bai, Cuixia Wu, Xibai Zeng
更新时间: 2021-01-13
摘要: Purpose Mineral-organic associations (MOAs) are the basic structural units of soil aggregates and are important reservoirs of nutrients for plants and soil microorganisms, determining the soil structure and fertility. However, the influence of exogenous dissolved organic matter (DOM) chemistry on the stability of MOAs is rarely reported. Materials and methods We first characterized different exogenous DOM through elemental analysis and spectroscopy analysis technologies. Then, a chamber incubation experiment was conducted with DOM addition concentration at 3 g C kg−1 red soil. Principal component analysis, redundancy analysis, and the partial least squares path model were used to better understand the effect of exogenous DOM chemistry on the stability of MOAs. Results and discussion The addition of DOM into the red soil significantly increased not only the organic carbon both in the bulk soil and the soil heavy fraction, but also the soil combined humus and the soil mineral-organic compound quantity. Moreover, the rice straw-derived DOM had the best effect on improving the soil mineral-organic compound quantity/degree (additional), followed by the animal-derived DOM, while the fulvic acid increased it the least. The ratios of elements (C/N ratio, O/C ratio, and H/C ratio), aromaticity (SUVA254), and phenolic C content of exogenous DOM had positively significant contributions to the stability of MOAs. Conclusions The rice straw-derived DOM had the greatest enhancement on the stability of the MOAs for its higher C/N ratio and phenolic groups content, so the exogenous DOM characteristics could be as an indicator in predicting the stability of the MOAs and evaluating the soil fertility.

158. 题目: An improved genetic algorithm for determining modified water-retention model for biochar-amended soil
文章编号: N21011305
期刊: CATENA
作者: Xuguang Xing, Ye Liu, Ankit Garg, Xiaoyi Ma, Ting Yang, Long Zhao
更新时间: 2021-01-13
摘要: Biochar has been globally recognized as a soil amendment to ameliorate the degraded soil structures. We investigated the different biochar percentages contributed to the changes in soil water retention, soil infiltration, and water-holding capacity of one dimensional scale. Besides, infiltration models were compared, and an improved genetic algorithm (GA) combined with multi-objective optimization and elitist strategy was proposed to upgrade the modified van-Genuchten (VG) model. Results indicated that observed cumulative infiltration displayed reductions by 14.06%, 46.62%, and 71.78% for the soil mixed with 5%, 10%, and 15% biochar, respectively, relative to the pure soil. The Kostiakov model was more effective than the Philip model in predicting cumulative infiltration. Furthermore, the constructed modified VG model based on the inversed hydraulic parameters was capable of predicting soil moisture at suction less than 2070 kPa (i.e., 1.38 times wilting point) but caused an underestimation beyond it. This research has the potential to replace the soil water retention curve (SWRC) measurement by one-dimensional infiltration experiment with parameters inversed from the improved GA combined with a modified VG model. It is time-saving and efficient during the SWRC study.

159. 题目: A critical review on silver nanoparticles: From synthesis and applications to its mitigation through low-cost adsorption by biochar
文章编号: N21011304
期刊: Journal of Environmental Management
作者: Md Anwarul Islam, Mohan V. Jacob, Elsa Antunes
更新时间: 2021-01-13
摘要: Silver nanoparticles are one of the most beneficial forms of heavy metals in nanotechnology applications. Due to its exceptional antimicrobial properties, low electrical and thermal resistance, and surface plasmon resonance, silver nanoparticles are used in a wide variety of products, including consumer goods, healthcare, catalysts, electronics, and analytical equipment. As the production and applications of silver nanoparticles containing products increase daily, the environmental pollution due to silver nanoparticles release is increasing and affecting especially the aqueous ecosystem. Silver nanoparticles can kill useful bacteria in soil and water, and bioaccumulate in living organisms even at low concentrations from 10−2 to 10 μg/mL silver can show antibacterial effect. On the other hand, the maximum silver discharge limit into freshwater is 0.1 μg/L and 3.2 μg/L for Australia and the USA, respectively. To reduce its toxic consequences and meet the regulatory guidelines, it is crucial to remove silver nanoparticles from wastewater before it is discharged into other water streams. Several technologies are available to remove silver nanoparticles, but the adsorption process using low-cost adsorbents is a promising alternative to mitigate silver nanoparticle pollution in the bulk stage. As one of the low-cost adsorbents, biochar produced from the biomass waste could be a suitable adsorbent. This review focuses on collating the latest evidence on silver nanoparticle production, applications, environmental consequences, and cost-effective technological approaches for silver removal from wastewater.

160. 题目: Restriction of dissolved organic matter on the stabilization of Cu(II) by phosphate
文章编号: N21011303
期刊: Environmental Science and Pollution Research
作者: Xiang Ding, Zhongwu Li, Weihua Xu, Mei Huang, Jiajun Wen, Changsheng Jin, Mi Zhou
更新时间: 2021-01-13
摘要: The precipitation of Cu(II) by phosphate and the influence of dissolved organic matter (DOM) on the precipitation are essential for the fate of Cu(II) in aquatic environments. In this study, the influence of DOM on the reaction of phosphate with Cu(II) was investigated. Here, 51.61%, 29.75%, and 24.32% of the added Cu(II) (50 μM) precipitated without DOM and with the addition of fulvic acid (FA) and humic acid (HA), respectively, owing to the reaction with phosphate (50 μM). Excitation-emission matrix spectroscopy-parallel factor (PARAFAC) and two-dimensional ultraviolet-visible correlation spectroscopy analyses were conducted to characterize the influence of DOM on the precipitation of Cu(II) with phosphate. One humic-like and two protein-like fluorescent components were identified by the PARAFAC model for FA, whereas two humic-like fluorescent components and one protein-like fluorescent component were validated for HA. The humic-like components had primary roles, whereas the protein-like components had secondary roles in limiting the precipitation of Cu(II) with phosphate. Cu(II) binding to DOM chromophores initially occurred at shorter wavelengths, and then at longer wavelengths. Phenolic and carboxylic constituents had important roles, and HA exhibited more binding sites than FA. Therefore, humic-like fluorescent components and chromophores containing phenolic and carboxylic groups and functional groups with peaks at short wavelengths (200–220 nm) were primarily responsible for restricting the precipitation of Cu(II) with phosphate.

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