141. 题目: Fluorescence excitation-emission matrix as a novel indicator of assimilable organic carbon in wastewater: Implication from a coal chemical wastewater study
期刊: Science of The Total Environment
作者: Shu Wang, Yufang Li, Kang Xiao, Xia Huang
摘要: Assimilable organic carbon (AOC) is recognized as an important parameter to evaluate the biostability of water. Studies have been carried out to investigate the easier and faster AOC detection methods in recent years. In our study, the relationship between AOC and excitation-emission matrix (EEM) was investigated through analysis of wastewater from a coal chemical industrial corporation, including biochemical effluent, ultrafiltration effluent, and reverse osmosis concentrate. Considering the influence of water sample properties on AOC distribution, these water samples were fractionated according to their hydrophilicity and acid/base properties. Neutrals and hydrophobic acids were major components of total organic carbon and AOC concentration of these fractions were measured. EEM spectra of water samples were divided into five regions according to fluorescence peaks. Distribution of fluorescence region integration (FRI) of water samples were also calculated, as well as other fluorescence parameters. Statistical analysis showed that the concentration of AOC presented high positive correlation with the FRI in region H2, with R2 = 0.696. Monte Carlo simulation also proved that the proportion of significant R2 (p < 0.05) was high at 89.1%, suggesting that the model was reliable at least at the qualitative level. In that case, FRI in Region H2 could be an indication for AOC concentration in water samples. Our findings focus on fundamental insights into establishing relationship between spectroscopy method and AOC in wastewater and provide an easier way of accessing AOC in coal chemical industrial wastewater. Further investigation could be oriented to the dynamic analysis of AOC transformation and tracing.
142. 题目: Nitrate shifted microenvironment: driven aromatic-ring cleavage microbes and aromatic compounds precursor biodegradation during sludge composting
期刊: Bioresource Technology
作者: Mingzi Shi, Chengguo Liu, Yumeng Wang, Yue Zhao, Zimin Wei, Maoyuan Zhao, Caihong Song, Yan Liu
摘要: The aim of this study was to clarify the aromatic cleavage pathways and microbes involved in the adverse effect of nitrate on aromatic compounds humic substances during sludge composting. Results showed that the functional microbes involved in aromatic compounds humic substances precursors (catechol, tyrosine, tryptophan and phenylalanine) cleavage pathways significantly enriched after nitrate addition. Linear regression analysis showed that aromatic-ring cleavage functional microbes exhibited significant negative correlation with aromatic humic substances (p<0.05). Furthermore, network analysis indicated that most of microbial communities prefer cooperative with aromatic-ring cleavage functional microbes. Structural equation model further revealed that composting microenvironment drove aromatic-ring cleavage functional microbes activities, resulting in the biodegradation of complex aromatic compounds. This study parsed the effect of a negative factor on aromatic compounds humic substances from an opposing perspective. Properly controlling nitrate concentration and aromatic-ring cleavage functional microbes involved in precursors cleavage was suggested to the practice of composting.
143. 题目: Origin of the Chemical Composition of São Francisco Ultra-Fresh Thermal Water (Itabira Region, Minas Gerais, Brazil)
期刊: Applied Geochemistry
作者: Dariusz Dobrzyński, Marek Duliński, Łukasz Birski, Jordi Barrett
摘要: Geochemical studies documented the composition of ultra-fresh thermal water in the Fazenda Giráu, near Itabira (Minas Gerais state, Brazil) for the first time. The studied water is characterized by temperature of 35 °C, very low electric conductivity (approx. 20 μS/cm), uncommon Mg-Ca-HCO3-NO3 hydrochemical type, and an elevated radon concentration (about 500 Bq/L). The presence of tritium suggests the modern age of studied water, contained in highly resistant quartzite-dominated aquifer rocks. Application of a geothermometric approach gave an estimation of the equilibrium temperature in the geothermal system at about 42 °C. Inverse geochemical modelling quantified water-rock reactions responsible for the observed groundwater chemistry. Decomposition of soil organic matter and decay of primary (feldspars, biotites, muscovite) and secondary (montmorillonites, illite) aluminosilicate minerals accompanied by kaolinite and gibbsite formation are the dominant processes forming chemical composition of water. The investigated water has balneotherapeutic potential due its elevated temperature and high concentrations of radon and silicic acid.
144. 题目: A novel intelligence approach based active and ensemble learning for agricultural soil organic carbon prediction using multispectral and SAR data fusion
期刊: Science of The Total Environment
作者: Thu Thuy Nguyen, Tien Dat Pham, Chi Trung Nguyen, Jacob Delfos, Robert Archibald, Kinh Bac Dang, Ngoc Bich Hoang, Wenshan Guo, Huu Hao Ngo
摘要: Monitoring agricultural soil organic carbon (SOC) has played an essential role in sustainable agricultural management. Precise and robust prediction of SOC greatly contributes to carbon neutrality in the agricultural industry. To create more knowledge regarding the ability of remote sensing to monitor carbon soil, this research devises a state-of-the-art low cost machine learning model for quantifying agricultural soil carbon using active and ensemble-based decision tree learning combined with multi-sensor data fusion at a national and world scale. This work explores the use of Sentinel-1 (S1) C-band dual polarimetric synthetic aperture radar (SAR), Sentinel-2 (S2) multispectral data, and an innovative machine learning (ML) approach using an integration of active learning for land-use mapping and advanced Extreme Gradient Boosting (XGBoost) for robustness of the SOC estimates. The collected soil samples from a field survey in Western Australia were used for the model validation. The indicators including the coefficient of determination (R2) and root - mean – square - error (RMSE) were applied to evaluate the model's performance. A numerous features computed from optical and SAR data fusion were employed to build and test the proposed model performance. The effectiveness of the proposed machine learning model was assessed by comparing with the two well-known algorithms such as Random Forests (RF) and Support Vector Machine (SVM) to predict agricultural SOC. Results suggest that a combination of S1 and S2 sensors could effectively estimate SOC in farming areas by using ML techniques. Satisfactory accuracy of the proposed XGBoost with optimal features was achieved the highest performance (R2 = 0.870; RMSE = 1.818 tonC/ha) which outperformed RF and SVM. Thus, multi-sensor data fusion combined with the XGBoost lead to the best prediction results for agricultural SOC at 10 m spatial resolution. In short, this new approach could significantly contribute to various agricultural SOC retrieval studies globally.
145. 题目: Humification process and mechanisms investigated by Fenton-like reaction and laccase functional expression during composting
期刊: Bioresource Technology
作者: Qiuqi Niu, Qingran Meng, Hongxiang Yang, Yiwu Wang, Xiaolan Li, Gen Li, Qunliang Li
摘要: This study aims to explore the impacts of the Fenton-like reaction on hydrogen peroxide, hydroxyl radicals, humic substance (HS) formation, laccase activity and microbial communities during composting to optimize composting performances. The results indicated that the activity of laccase in the presence of the Fenton-like reaction (HC) (35.92 U/g) was significantly higher than that in the control (CP) (29.56 U/g). The content of HS in HC (151.91 g/kg) was higher than that in CP (131.73 g/kg), and amides, quinones, aliphatic compounds and aromatic compounds were promoted to form HS in HC by 2D-FTIR-COS analysis. Proteobacteria contributed most greatly to AA1 at phylum level, Pseudomonas and Sphingomonas abundances increased in HC. Redundancy analysis indicated that there was a strong positive correlation among the Fenton-like reaction, laccase and HS. Conclusively, the Fenton-like reaction improved the activity of laccase, promoted the formation of HS and enhanced the quality of compost.
146. 题目: Trace metals and metalloids and Ga/Al ratios in grey shale weathering profiles along a climate gradient and in batch reactors
作者: Justin B. Richardson, Ivan C. Mischenko, Trevor J. Mackowiak, Nicolas Perdrial
摘要: Shale is an important lithology globally due to its wide spatial abundance and potentially high trace metal and metalloid (TMM) geochemistry, which can be potentially inherited by its overlying soils. Unlike other soils, shale-derived soils inherit organic matter and oxides (Fe and Mn) which promote accumulation and retention of both geogenic and exogeneous TMMs. Here, we explore TMMs in seven grey shales weathering profiles along a north–south transect spanning the western flank of the Appalachian Mountains from New York to Tennessee. Overall, total TMM concentrations in the grey shales and their soils were below concentrations known to be toxic and below concentrations observed in black shales. Tau values show that shale-derived soils are net accumulators of many TMMs (As, Cd, Co, Cu, Ni, Pb, Sb, Sn and Zn) but others (Cr, W, and V) showed a net depletion. Many of the TMMs had high proportions (5–50%) that were sequestered in reducible phases (amorphous and crystalline Fe oxides) but few TMMs were associated with oxidizable phases (organic matter, reduced minerals). Sulfides and oxides (Mn nor Fe) were not detected by X-ray diffraction (<2% g/g). TMM accumulation and release during weathering was not extensively related to climate or soil development/age as we hypothesized, potentially due to localized effects of vegetation, geomorphology, pollution, and physicochemical parameters of the shale. Our laboratory batch reactor experiments indicated that some TMMs had highest release rates under oxic, acidic conditions with organic acids present (Cr, Ga, Sn, Sb, and W) implying aluminosilicate dissolution control or under slightly acidic, reduced conditions (As, Cd, Co, Cu, Ni, Pb, V, and Zn), suggesting association with geogenic oxides. Total Ga/Al ratios in rock to soil profiles were not varying significantly across the climate-soil development gradient, despite batch reactor acidic conditions generating low Ga/Al ratios. This implies weathering of shales is dominated by processes that do not fractionate Ga/Al ratio (organic or inorganic colloid production) as our laboratory results suggests oxic, acidic aluminosilicate weathering should generate a high Ga/Al solid phase.
147. 题目: Enhancing phosphorus recovery from sewage sludge using anaerobic-based processes: Current status and perspectives
期刊: Bioresource Technology
作者: Bohan Yu, Xiangmin Xiao, Jianwei Wang, Meng Hong, Chao Deng, Yu-You Li, Jianyong Liu
摘要: Anaerobic-based processes are green and sustainable technologies for phosphorus (P) recovery from sewage sludges economically and are promising in practical application. However, the P release efficiency is always not satisfied. In this paper, the P release mechanisms (regarding to different P species) from sewage sludge using anaerobic-based processes are systematically summarized. The obstacles of P release and the updated achievements of enhancing P release from sewage sludges are analyzed and discussed. It can be concluded that different P species can release from sewage sludge via different anaerobic-based processes. Extracellular polymeric substances and excessive metal ions are the two main limiting factors to P release. Acid fermentation and anaerobic fermentation with sulfate reduction could be two promising ways, with P release efficiencies of up to 64% and 63%. Based on the summarization and discussion, perspectives on practical application of P recovery from sewage sludge using anaerobic-based processes are proposed.
148. 题目: Tetracycline adsorption mechanisms by NaOH-modified biochar derived from waste Auricularia auricula dregs
期刊: Environmental Science and Pollution Research
作者: Jiawei Zhao, Yingjie Dai
摘要: Tetracycline (TC) is not easy to degrade in human or animal and can even be converted to more toxic substances. The overuse and wanton discharge of TC also caused serious problem of water pollution. This study investigated the removal of TC by biochar (BC) prepared from waste Auricularia auricula dregs and modified with NaOH by characterizing the pH and adsorption kinetics, and using isotherm models. Three BC samples were prepared and that produced using the highest concentration of NaOH (8 M) was more suitable for removing TC, where the adsorption amount was 26.65 mg/g. Pseudo-second order and Freundlich models both fitted well to the adsorption kinetics, and diffusion of the liquid film was considered the rate-controlling step. The multivariate mechanism involved electron interplay, H-bonding, and π–π electron donor–acceptor interactions. The results of this work can not only make the waste Auricularia auricula dregs resourceful, but also provide a new method for the removal of TC in wastewater, which is of great practical significance.
149. 题目: Removal of emerging contaminants (bisphenol A and antibiotics) from kitchen wastewater by alkali-modified biochar
期刊: Science of The Total Environment
作者: Ye Tang, Ye Li, Lu Zhan, Dong Wu, Suhua Zhang, Ruirui Pang, Bing Xie
摘要: Using current wastewater treatment technologies, it can be challenging to remove the emerging contaminants (ECs) present in kitchen wastewater (KW) of complex compositions and high organic content. In this study, biochar, derived from straw, was modified as an adsorbent to remove ECs such as bisphenol A (BPA), tetracycline (TC) and ofloxacin (OFL) from a complex KW system. An alkali-modified biochar, having larger specific surface areas and stronger hydrophobicity, was found to exhibit a higher adsorption capacity, with more than 95% of the target ECs being removed. Indeed, in a static operation mode, the alkali-modified biochar had maximum adsorption capacities of 71.43, 101.01 and 54.05 mg/g for BPA, TC, and OFL, respectively. The adsorption kinetics and isotherms models indicated that the adsorption process was controlled by chemisorption, as well as the monolayer adsorption of contaminants onto the external and internal surfaces of the alkali-modified biochar. The adsorption of TC and OFL was significantly affected by the initial pH values of KW. However, the presence of different environmental factors (COD, NH4+ and PO43−) had little effects on the adsorption of the contaminants. The alkali-modified biochar was further tested in a fixed-bed column where the maximum dynamic adsorption capacities for BPA and OFL were 55 and 45 mg/g, representing about 75% and 83% of the static saturated adsorption capacities. These findings can be of major significance for the application of alkali-modified biochar in the removal of ECs from complex KW systems.
150. 题目: Factors controlling spatial variation in soil aggregate stability in a semi-humid watershed
期刊: Soil and Tillage Research
作者: Pingping Zhang, Yunqiang Wang, Lan Xu, Ruijie Li, Hui Sun, Jingxiong Zhou
摘要: Soil aggregate stability (SAS) is a key soil property that affects soil erosion and soil ability to support ecosystem functions. The effects of different environmental factors on SAS are extensively documented. However, the relative importance of the factors that drive variation in SAS at watershed scale is not entirely clear. To investigate the effects of the interactions of environmental variables on spatial variation in SAS, 88 sampling sites were selected across an entire watershed (1.1 km2) on the Chinese Loess Plateau (CLP), from where undisturbed soil samples were collected at the 0–10 and 10–20 cm soil depths. Three indices were used to evaluate the SAS — water-stable aggregates greater than 0.25 mm (WSA>0.25, %), mean weight diameter (MWD, mm) and mean geometric diameter (MGD, mm). The results showed that variation of SAS across the watershed was moderate, with coefficient of variation (CV) of 23.5–38.9 %. From combined Spearman’s correlation analysis (r), redundancy analysis (RDA) and structural equation modelling (SEM), it was found that soil intrinsic properties, mainly soil texture and organic carbon content (SOC), were the primary control on SAS variation. Topographic attributes, primarily wetness index (TWI) and altitude, were also important controls on SAS. These controls were either the direct or indirect effect through SOC dynamics, spatial distribution of land use (LUT) or vegetation cover (NDVI). The effect of LUT on SAS was mainly driven by SOC and TWI at the 0–10 cm depth but by NDVI and TWI at the 10–20 cm depth. SAS was positively correlated with sand content and SOC, but negatively correlated with silt content, altitude, TWI and NDVI. For LUT, SAS in the apple orchard was significantly lower than in shrubland and grassland, however, it was comparable with that in forest. Considering the effects of improving soil structure and the related economic cost, natural restoration of grassland was a good choice for preventing soil erosion in the study area. The results of this study could deepen our understanding of the controls on SAS variation and therefore become useful in soil management and vegetation restoration decisions on CLP and other regions with similar conditions.
151. 题目: Impact of EfOM in the Elimination of PPCPs by UV/chlorine: Radical chemistry and toxicity bioassays
期刊: Water Research
作者: Yuru Wang, Mauricius Marques dos Santos, Xinxin Ding, Jérôme Labanowski, Bertrand Gombert, Shane Allen Snyder, Jean-Philippe Croué
摘要: The UV/chlorine process as a potential tertiary municipal wastewater treatment alternative for removing refractory PPCPs has been widely investigated. However, the role of effluent organic matter (EfOM) on the radical chemistry and toxicity alteration is unclear. The elimination of two model PPCPs, primidone (PRM) and caffeine (CAF), by the co-exposure of UV and free chlorine was investigated to elucidate the impact of EfOM. Experimental results indicated that both •OH and reactive chlorine species (RCS) were importantly involved in the decay of PRM at acidic condition, while ClO• played dominant role at alkaline pH. The decay of CAF was dominated by ClO• under all conditions. Chlorine dose, initial contaminant concentration, solution pH, and water matrix affect the process efficiency at varying degree resulting from their specific effect on the radical speciation in the system. Presence of EfOM isolate remarkably inhibited the decay of PRM and CAF by preferentially scavenging RCS and particularly ClO•. Good correlations (linear for PRM and exponential for CAF) between UV absorbance at 254 nm and the observed pseudo first-order rate constants (k'obs) for all EfOM solutions were obtained, demonstrating the importance of aromatic moieties in inhibiting the degradation of targeted contaminants by UV/chlorine process. Degradation of PRM/CAF in reconstituted effluent spiked with the major effluent constituents (i.e., EfOM isolates, Cl-, HCO3-, and NO3-) was comparable to the results obtained with the real WWTP effluent and fit well to the correlation between k'obs and UV absorbance at 254 nm, suggesting that EfOM isolates can be used to determine the efficiency of UV/chlorine process in real effluent. EfOM serves as the main precursors of adsorbable organic chlorine in the UV/chlorine treatment. Bioassays indicated that chlorine-containing compounds could induce oxidative stress, mitochondrial dysfunction, and increase the cell DNA damage. Among evaluated treatment conditions, the nature of EfOM, hydrophobic versus transphilic fraction, is likely the predominant factor affecting the cytotoxicity. Meanwhile the UV/chlorine treatment can significantly reduce the cytotoxicity of the EfOM isolates. However, adding high level of selected contaminants (e.g., PRM and CAF) can inhibit this phenomenon due to competition with reactive radicals.
152. 题目: Catalytic Conversion of CO 2 to Formate Promoted by a Biochar-Supported Nickel Catalyst Sourced from Nickel Phytoextraction Using Cyanogen-Rich Cassava
期刊: ACS Earth and Space Chemistry
作者: Babatunde J. Akinbile, Leah C. Matsinha, Abayneh A. Ambushe, Banothile C. E. Makhubela
摘要: In this work, we have demonstrated for the first time that a cyanogen-glucoside-rich cassava plant (Manihot esculenta) is highly efficient in phytoextraction (up to 88%) of nickel to obtain a type of bio-ore comprising Ni nanoparticles (NPs) supported on the recovered plant material. Up to 1251 ppm was extracted from low Ni concentration soil by the cassava plant, as was measured by flame atomic absorption spectrometry. The bio-ore was used as a resource for preparing a heterogeneous catalyst (Ni@CassCat), in which Ni NPs are supported on mesoporous biochar following a calcination step. Ni@CassCat was characterized using high-resolution transmission electron microscopy with energy-dispersive X-ray, scanning electron microscopy with energy-dispersive X-ray, powder X-ray diffraction, N2-sorption techniques, and ultraviolet–visible spectrometry. Subsequently, Ni@CassCat was used as a heterogeneous catalyst to hydrogenate carbon dioxide (CO2) to formate with a turnover number of 485. Furthermore, the recyclability of Ni@CassCat was demonstrated. This work demonstrates a two-pronged approach to sustainability, transforming two waste streams (mine tailings and CO2) to value.
153. 题目: Response of soil characteristics to biochar and Fe-Mn oxide-modified biochar application in phthalate-contaminated fluvo-aquic soils
期刊: Ecotoxicology and Environmental Safety
作者: Xipeng Chang, Zhengguo Song, Yalei Xu, Minling Gao
摘要: Biochar (BC) derived from agricultural biomass is effective at immobilizing phthalate in the agricultural soil environment. In this study, we assessed the effects of 0.5%, 1%, and 2% BC and Fe-Mn oxide-modified biochar (FMBC) addition on dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) residues and biochemical characteristics in the rhizosphere soil of mature wheat polluted with DBP and DEHP using a pot experiment. Scanning electron microscopy showed that the surfaces and pores of BC and FMBC adhered soil mineral particles after remediation. Therefore, DBP and DEHP residues were increased in BC- and FMBC-treated soils. Illumina HiSeq sequencing showed that, compared with the control, BC and FMBC addition significantly enhanced the relative abundance of Firmicutes and reduced Proteobacteria. The abundance of Sphenodons and Pseudomonas, which degrade phthalates, tended to be higher in FMBC-amended soils than in BC-amended and control soils. This result may be related to an increase in available nutrients and organic matter following BC and FMBC application. Subsequently, the changes in soil bacterial abundance and community structure induced an increase in polyphenol oxidase, β-glucosidase, neutral phosphatase, and protease activity in BC and FMBC remediation. In comparison with the BC treatment, FMBC addition had a significantly positive effect on enzyme activity, and the microbial structure and was therefore more effective at immobilizing DBP and DEHP in the soil. Thus, our findings strongly suggest that FMBC is a reliable remediation material for phthalate-contaminated soil.
154. 题目: An efficient biochar synthesized by iron-zinc modified corn straw for simultaneously immobilization Cd in acidic and alkaline soils
期刊: Environmental Pollution
作者: Tingting Yang, Yingming Xu, Qingqing Huang, Yuebing Sun, Xuefeng Liang, Lin Wang, Xu Qin, Lijie Zhao
摘要: Synthetic functional biochar using agricultural waste as raw materials not only serves as an effective means for recycling waste but can also be employed for the remediation of heavy metal contaminated soil. However, the associated effect and mechanism underlying the immobilization of functional biochar in acidic and alkaline soils remain unclear. In this study, a novel iron-zinc oxide composite modified corn straw (Fe/Zn-YBC) was prepared and applied for the remediation of cadmium-contaminated acidic and alkaline farmland soils. The results showed that the addition of Fe/Zn-YBC increased the pH, cation exchange capacity (CEC), and dissolved organic carbon (DOC) in acidic soil, while increased the pH and DOC in alkaline soil. After immobilization for 42 d, the DTPA-Cd content in acidic and alkaline soils treated with Fe/Zn-YBC decreased by 12.77 %–57.45 % and 23.73 %–52.50 %, respectively. Fe/Zn-YBC treatment promoted the transformation of the exchangeable fraction into the Fe/Mn oxyhydroxide fraction of Cd, and increased the abundance and diversity of bacterial communities in the two soils. Furthermore, the SEM-EDS, XRD and FTIR results for Fe/Zn-YBC separated from the test soils showed that the distribution of Cd adsorbed on Fe/Zn-YBC was positively correlated with Fe, Zn, and O. Additionally, the Cd complexes (CdCO3, CdZnFe2O4 and CdO) detected on Fe/Zn-YBC indicated that the primary immobilization mechanism of Fe/Zn-YBC involved the complexation of Cd and Fe, Zn oxides, and the precipitation of Cd and CO32− in acidic and alkaline soils. The efficient remediation capacity and associated mechanism for this novel functional biochar provide insights for improved remediation of heavy metal contaminated farmland soil.
155. 题目: Humic Acid Promotes Volatile Fatty Acids Production from Excess Sludge in Anaerobic Fermentation
期刊: ACS Sustainable Chemistry & Engineering
作者: Jiali Zou, Gongxia Li, Dayang Zheng, Yayi Wang, Cang Feng, Yue Sun, Maoling Juan, Xinxing Bai, Min Wu
摘要: Excess sludge was used to produce volatile fatty acids (VFAs) by fermentation, which has recently attracted much attention because the sludge-derived VFAs were able to function as a kind of ideal carbon source for wastewater biological treatment. This study specifically targeted the mechanism behind the effects of humic acid (HA) on promoting production of VFAs from excess sludge during acidogenic fermentation. The HA was characterized using Fourier-transform infrared (FTIR) spectrum, 13C nuclear magnetic resonance (13C NMR), and 3D excitation–emission matrix (3D-EEM). When HA was present at 1.20 g/g of total chemical oxygen demand, the content of VFAs produced was maximal (1752 mg COD/L) and was about 2.15 times that of the control without HA (815 mg/L). Mechanism exploration revealed that the dominant population of microbial community in the sample with added HA had shifted to Firmicutes, which was related to the acid production. More importantly, the electron transfer between nicotinamide adenine dinucleotide hydrogen (NADH) and nicotinamide adenine dinucleotide (NAD+) was enhanced by HA, contributing to improve the VFAs’ accumulation. In contrast, the activities of the key enzymes, including acetic kinase (AK) and phosphotransferase (PTA), in the acidogenic stage had little change with HA addition, which meant that HA could not stimulate acidification by the way of changing enzymatic activities.
156. 题目: Interactions between organic matter and Fe (hydr)oxides and their influences on immobilization and remobilization of metal(loid)s: A review
期刊: Critical Reviews in Environmental Science and Technology
作者: Yanping Bao, Nanthi S. Bolan, Jinhao Lai, Yishun Wang, Xiaohu Jin, M. B. Kirkham, Xiaolian Wu, Zheng Fang, Yan Zhang, Hailong Wang
摘要: Fe (hydr)oxides and organic matter (OM) are two of the main active substances ubiquitously occurring in natural environments. Fe (hydr)oxides rarely exist as a discrete component in natural environments, but they can interact readily with OM and are usually associated with OM to form Fe-OM associations. The interaction of Fe (hydr)oxides with OM will significantly change the binding characteristics of Fe (hydr)oxides toward metal(loid)s. In this review paper, firstly, interaction mechanisms, including the adsorption of OM onto Fe (hydr)oxides and the co-precipitation of OM and Fe (hydr)oxides, and factors affecting these interactions are summarized. Secondly, the characteristics of Fe-OM associations via adsorption and co-precipitation processes are compared. Then, the immobilization and remobilization of metal(loid)s influenced by interaction with OM and Fe (hydr)oxides are discussed. Finally, suggestions for future studies concerning the interactions between Fe (hydr)oxides and OM and their influences on immobilization and remobilization of metal(loid)s are offered. Therefore, this review provides helpful guidance for better evaluation of the bioavailability and mobility of metal(loid)s as impacted by Fe-OM associations in the natural environment.
157. 题目: Efficacy of in situ active capping Cd highly contaminated sediments with nano-Fe2O3 modified biochar
期刊: Environmental Pollution
作者: Qunqun Liu, Yanqing Sheng, Xiaozhu Liu
摘要: Effective remediation of Cd polluted sediment is imperative for its potential damages to aquatic ecosystem. Biochar (BC) and nano-Fe2O3 modified BC (nFe2O3@BC) were conducted to remedy Cd highly contaminated sediments, and their performances, applicable conditions, and mechanisms were investigated. After 60 d capping, both BC and nFe2O3@BC capping inhibited Cd release from sediment to overlying water and porewater (reduction rates >99%). The released Cd concentrations in overlying water with nFe2O3@BC capping decreased by 1.6–11.0 times compared to those of BC capping, indicating nFe2O3@BC presented a higher capping efficiency. Notably, the increases of acidity and disturbance intensity of overlying water weakened the capping efficiencies of nFe2O3@BC and BC. BC capping was inappropriate in acidic and neutral waters (pH 3, 5, and 7) because Cd maintained a continuous release after 15 d, while nFe2O3@BC capping was valid in all pH treatments. Under 150 rpm stirring treatment, Cd release rates with BC and nFe2O3@BC capping decreased after 15 d and 30 d, respectively. At 0 and 100 rpm treatments, Cd releases treated by nFe2O3@BC capping finally kept a balance, indicating nFe2O3@BC was valid at low disturbance intensity. BC and nFe2O3@BC capping inhibited Cd release via weakening the influences of pH and disturbance on sediment. However, capping layers should be further processed because most adsorbed Cd in capping layers (>98%) would be re-released into overlying water. Meanwhile, excessive application of nFe2O3@BC could increase the risk of Fe release. The results provide novel insights into the potential applications of nFe2O3@BC and BC in situ capping of Cd polluted sediments in field remediation.
158. 题目: CQDs/biochar from reed straw modified Z-scheme MgIn2S4/BiOCl with enhanced visible-light photocatalytic performance for carbamazepine degradation in water
作者: Kemin Qi, Mengxi Song, Xiaoyun Xie, Yuan Wen, Zirun Wang, Bin Wei, Zhaowei Wang
摘要: The application of environmental-friendly and sustainable green materials in constructing photocatalysts to degrade pharmaceuticals and personal care products (PPCPs) attracts more attention. Herein, biochar (BC) or biomass carbon quantum dots (CQDs) were used to modify MgIn2S4/BiOCl (MB) heterojunction photocatalyst with Z-scheme structure, and improved the photocatalytic degradation performance for carbamazepine (CBZ) in the aqueous solution. Both BC and CQDs could form electron transfer interface with MB heterojunction, resulting in the photodegradation rate of MgIn2S4/BiOCl/CQDs (MBC, 96.43%) and MgIn2S4/BiOCl/BC (MBB, 88.09%) to CBZ within 120 min visible-light irradiation, which were significantly higher than that of MB (65.84%). Moreover, photoelectrochemical and photoluminescence tests verified that CQDs could act as a bridge for storing and transferring electrons in the entire Z-scheme system. Thence, compared with MBB, MBC could produce more •OH and •O2− under the visible light, which was indicated by the results of radical quenching experiments and electron paramagnetic resonance. Interestingly, under the natural sunlight, the photocatalytic performance of MBC to CBZ was even better than under laboratory conditions. In addition, the TOC removal efficiencies of MBB and MBC could reach 85.09% and 93.79% respectively, and ECOSAR program was utilized to further evaluate the eco-toxicity of CBZ and the intermediates towards fish, daphnid, and green algae, indicating that the photocatalytic process involving MBB and MBC showed outstanding toxicity reduction performance. Finally, compared with other composites, MBB and MBC showed higher photocatalytic performance and lower energy consumption, which would provide a green strategy for biochar materials in the photocatalytic treatment of PPCPs in water.
159. 题目: Impact of source variability and hydrodynamic forces on the distribution, transport, and burial of sedimentary organic matter in a tropical coastal margin: the Gulf of Thailand
期刊: Journal of Geophysical Research: Biogeosciences
作者: Yazhi Bai, Limin Hu, Bin Wu, Shuqing Qiao, Dejiang Fan, Shengfa Liu, Gang Yang, Jihua Liu, Narumol Kornkanitnan, Somkiat Khokiattiwong, Xuefa Shi
摘要: Carbon cycling in tropical margin is more extensive compared with other regions of the world. The goal of this study was to better understand the origins, transport, and burial of sedimentary organic matter (SOM) in the Gulf of Thailand (GOT) from coastal margin of Southeast (SE) Asia, which serve as a major depository of ﬁne-grained sediments and the associated organic carbon (OC). The results revealed a variety of organic matter (OM) inputs and the selective transport of fine sediment, resulting in preferential dispersal of terrigenous SOM in the GOT. Bulk OC indices with low carbon/nitrogen ratios and enriched stable carbon isotope ratios (−24.2‰ to −20.4‰, mean −21.4 ± 0.56‰) are likely related to the presence of marine-derived OM and anthropogenic interference. A binary mixing model further clarified the significant contributions of terrestrial derived-OM within the upper and central GOT. The n-alkane compositions and principal component analysis indicated that a majority of the terrigenous SOM settles within the estuary in the upper GOT, while a selective dispersal of land-based SOM via long-distance transport towards the modern depocenter in the lower GOT. The characteristics of lower molecular weight n-alkanes also suggest anthropogenic OM input from petroleum-related contributions. Altogether, the depositional patterns and spatial heterogeneity of the SOM indicated by both the bulk and molecular signature reveal the important roles of source variability and the selective dispersal of land-based OM on the supply and accumulation of OC in the tropical coastal margin.
160. 题目: Modelling and mapping soil organic carbon stocks under future climate change in south-eastern Australia
作者: Bin Wang, Jonathan M. Gray, Cathy M. Waters, Muhuddin Rajin Anwar, Susan E. Orgill, Annette L. Cowie, Puyu Feng, De Li Liu
摘要: Soil organic carbon (SOC) plays a key role in the sequestration of carbon that could otherwise be warming the atmosphere. Climate change including increased temperature and changed rainfall will greatly impact the global SOC cycle. There are still significant gaps in our knowledge of the size of the global SOC pool and how future climate will affect SOC stocks and flows in many parts of the world, including Australia. In this study, we used SOC data in a Digital Soil Mapping framework to predict current and future SOC stocks across the state of New South Wales (NSW) in south-eastern Australia. In the first phase of the study we estimated the current SOC stock using multiple linear regression (MLR) and random forest (RF) modelling, and in the second phase we projected the change of SOC stocks in the near future (2050s) and far future (2090s) under two Shared Socio-economic Pathways (SSPs) scenarios based on 25 global climate models (GCMs) from the Coupled Model Inter-comparison Project Phase 6 (CMIP6). Our spatial modelling showed that estimated current SOC stocks in NSW decreased from east to west. Multi-GCM ensemble means suggested SOC stocks would decrease by 7.6–12.9% under SSP2-4.5 and 9.1–20.9% under SSP5-8.5 across NSW under future climate. The extent of change in SOC stocks varied spatially with the largest mean decrease of SOC stocks occurring in the North Coast and South East (alpine) regions of NSW. Our findings can support decision-making in land management and climate change mitigation strategies in NSW at the regional level. Furthermore, the modelling methods can be applied to other areas where edaphic and landscape properties, land use, and climate data are available.