1. 题目: Green manuring and crop residue management: Effect on soil organic carbon stock, aggregation, and system productivity in the foothills of Eastern Himalaya (India)
期刊: Soil and Tillage Research
作者: Meraj A. Ansari, Burhan U. Choudhury, Jayanta Layek, Anup Das, Rattan Lal, Vinay K. Mishra
摘要: Improving soil quality, especially the organic carbon (C) accumulation and soil aggregation through economically and environmentally sustainable alternatives, is the need for hill agriculture. A five-year (2012–13 to 2016–17) field experiment was conducted with four green manure treatments [green gram (Vigna radiata); cowpea (Vigna unguiculata); sesbania (Sesbania aculeata) along with non-green manuring] and three cropping systems [groundnut (Arachis hypogaea) –pea (Pisum sativum); maize (Zea mays) –pea, and maize + groundnut – pea] involving two levels of residue management practices [residue removal and residue retention]. The experiment was laid out in a split–split plot design and replicated three times. After five years of experimentation, the results showed that among green manure treatments, Sesbania had a significant effect (p < 0.05) on total soil organic C, C pool, and surface (0–0.15 m) soil aggregation. The increase in C pool (p < 0.05) in Sesbania-treated soil was 43.2% in the very labile C, followed by 40.8% in the labile C relative to those without green-manure. In addition, the profile (0–0.45 m depth) weighted average organic C stocks in Sesbania-treated soils were higher in active (+29.3%), passive (+20.8%), and total (TOC: + 24.1%) forms than in non-green manure soils. Sesbania-treated soils also exhibited a higher C-Lability index, water stable macro-aggregates, and a higher aggregate ratio (AR) than non-green manure soils. Among the three cropping systems studied, inter-cropping of maize and groundnut followed by peas increased (p < 0.05) the stock of C pools, water-stable aggregates, and ARs in soil relative to the other two cropping systems. Residue retention also increased C pools, C-Lability Index, and microbial biomass C in soil compared to residue removal. Therefore, the incorporation of Sesbania into maize+groundnut-pea cropping systems with residue retention is a recommended option to improve soil quality and productivity of maize cropping systems in the Indian Himalayan region.
2. 题目: Bismuth impregnated biochar for efficient uranium removal from solution: Adsorption behavior and interfacial mechanism
期刊: Science of The Total Environment
作者: Jun Liao, Xiaoshan He, Yong Zhang, Wenkun Zhu, Lin Zhang, Zhibing He
摘要: In this work, Bi2O3 doped horse manure-derived biochar was obtained by carbonizing the H2O2-modified horse manure loaded with bismuth nitrate under nitrogen atmosphere at 500 °C. The results showed that there was a sharp response between the as-prepared bismuth impregnated biochar and uranium(VI) species in solution, which resulted in a short equilibrium time (<80 min), a fast adsorption rate (about 5.0 mg/(g·min)), a high removal efficiency (93.9%) and a large adsorption capacity (516.5 mg/g) (T = 298 K, pH = 4, Ci = 10 mg/L and m/V = 0.1 g/L). Besides, the removal behavior of the bismuth impregnated biochar for uranium(VI) did not depend on the interfering ions and ion strength, except Al3+, Ca2+, CO32− and PO43−. These results indicated that the modified biochar might possess the potential of remediating the actual uranium(VI)-containing wastewater. Moreover, the interaction mechanism between Bi2O3 doped biochar and uranium(VI) species was further explored. The results demonstrated that the enrichment of uranium(VI) on the surface of the as-prepared biochar was controlled by various factors, such as surface complexation, ion exchange, electrostatic attraction, precipitation and reduction, which facilitated the adsorption of uranium(VI) on the bismuth impregnated biochar.
3. 题目: “Fertile island” of Tamarix Chinensis accelerated the carbon decomposition in the coastal wetlands of the Yellow River Delta, China
作者: Baoxian Tao, Qinghai Chen, Jingdong Wang, Baohuan Zhang, Haiyan Yuan, Yongjin Chen
摘要: Fertile island of shrub in the grass-dominated ecosystems would change the spatial distribution of soil organic carbon (SOC) and its fractions, adjusting the SOC dynamics and its response to global warming. However, the effects of fertile island on SOC decomposition and its temperature responses were still less known. An incubation experiment was conducted to investigate how the fertile island of Tamarix Chinensis affects SOC decomposition and its temperature sensitivity (Q10) in the coastal wetlands of the Yellow River Delta, China. Soil samples were collected from two areas, Tamarix Chinensis growing on bare land (SB) and the mixed-growing area of Tamarix Chinensis and herbage (SH). In each area, soil samples were collected from three sites, under the canopy of Tamarix Chinensis (CM), at the edge of the canopy (CP), and outside the canopy (OL). Results showed that the cumulative CO2 production increased from OL to CM due to the following reasons. Fertile island enriched SOC, labile fractions (i.e., O-alkyl and di- O-alkyl C), ammonium under the canopy in both sample areas and increased the relative abundance of labile SOC fractions (i.e., O-alkyl C) in SB, supplying more substrates for microbial decomposition. Subsequently, fertile island stimulated β-glucosidase and invertase activities, accelerating SOC decomposition. Moreover, fertile island decreased the Q10 value in the SB area because of the increased relative abundance of O-alkyl C. This study highlights the importance of O-alkyl C on SOC decomposition and its temperature sensitivity in the coastal wetlands of the Yellow River Delta.
4. 题目: Co-application of biochar and organic fertilizer promotes the yield and quality of red pitaya (Hylocereus polyrhizus) by improving soil properties
作者: Limei Chen, Xiaoying Li, Yutao Peng, Ping Xiang, Yuzhou Zhou, Bin Yao, Yaoyu Zhou, Chaoran Sun
摘要: This study evaluated the combined impact of biochar and organic fertilizer on the soil properties, yield and quality of red pitaya (Hylocereus polyrhizus). A two-year (2019 and 2020) field experiment was conducted to study the effects of 3 rates of biochar (with carbon fertilizer ratios of 0%, 3%, and 6% w/w) combined with 3 levels of organic fertilizer (22.5, 45, and 90 t ha−1) on soil properties, along with red pitaya yield and quality. The results showed that soil pH, total organic carbon, available nutrients (N, P, and K), the yield and qualities (reduced sugar, soluble protein, and soluble solid) of red pitaya increased with the application of organic fertilizer compared with no application of biochar and organic fertilizer (CK treatment), but the combined application of biochar and organic fertilizer was more effective than their sole application. Furthermore, a medium dose of organic fertilizer combined with 3% biochar (C3F2 treatment) and a high dose of organic fertilizer combined with 3% biochar (C3F3 treatment) had the highest yields of red pitaya in 2019 and 2020. However, an application of 6% biochar with a low dose of organic fertilizer treatment (C6F1) had the highest profit in 2020, not the C3F3 treatment. The highest profits were observed in the C3F2 (71.0 × 103 RMB·t−1) and C6F1 (51.2 × 103 RMB·t−1) treatments. From the point of view of red pitaya yield and economic benefits, 3% biochar +45 t ha−1 organic fertilizer was the recommended combination that showed the best synergistic effect.
5. 题目: Vegetation restoration facilitates belowground microbial network complexity and recalcitrant soil organic carbon storage in southwest China karst region
期刊: Science of The Total Environment
作者: Linan Hu, Qiang Li, Jiahui Yan, Chun Liu, Juxin Zhong
摘要: Soil organic carbon (SOC) is an important component of soil ecosystems, and soils are a hotbed of microorganisms playing critical roles in soil functions and ecosystem services. Understanding the interaction between SOC and soil microbial community is of paramount significance in predicting the C fate in soils following vegetation restoration. In this study, high-throughput sequencing of 16S rRNA and ITS genes combined with 13C NMR spectroscopy analysis were applied to characterize SOC chemical compounds and elucidate associated soil microbial community. Our results indicated that the contents of SOC, total nitrogen, total phosphorus, microbial biomass carbon and biomass nitrogen, dissolved organic carbon, available potassium, exchangeable calcium and soil moisture increased significantly (P < 0.05) along with the vegetation restoration processes from corn land, grassland, shrub land, to secondary and primary forests. Moreover, the Alkyl C and O-alkyl C abundance increased with vegetation recovery, but no significant differences of Alkyl C were observed in different successional stages. In contrast, the relative abundance of Methoxyl C showed an opposite trend. The dominate phyla Proteobacteria, Acidobacteria, Actinobacteria, Ascomycota and Basidiomycota were strongly related to SOC. And, SOC was found to be the determining factor shaping soil bacterial and fungal communities in vegetation restoration processes. The complexity of soil bacteria and fungi interactions along the vegetation restoration chronosequence increased. Determinism was the major assembly mechanism of bacterial community while stochasticity dominated the assembly of fungal community. Bryobacter, Haliangium, and MND1 were identified as keystone genera in co-occurrence network. Besides, the dominant functional groups across all vegetation restoration processes were mainly involved in soil C and N cycles and linked to the enhanced recalcitrant SOC storage. Our results provide invaluable reference to advance the understanding of microbe response to vegetation restoration processes and highlight the impact of microbes on recalcitrant SOC storage.
6. 题目: Removal of external influences from on-line vis-NIR spectra for predicting soil organic carbon using machine learning
作者: Muhammad Abdul Munnaf, Abdul Mounem Mouazen
摘要: External factors including moisture content negatively affect the prediction accuracy of soil organic carbon (SOC) using on-line visible and near-infrared (vis-NIR) spectroscopy. This study compared the performances of four algorithms to remove the moisture content effect [direct standardization (DS), piecewise direct standardization (PDS), external parameter orthogonalization (EPO), and orthogonal signal correction (OSC)] against non-corrected (NC) spectral models developed with partial least squares regression (PLSR), support vector machine (SVM), random forest (RF), and M5Rules regression. An on-line soil sensing platform coupled with a vis-NIR spectrophotometer (305–1700 nm) was used to scan twelve agricultural fields in Belgium and France. A total of 372 soil samples collected during the on-line measurement were divided into a calibration (260) and a prediction (112) dataset, using the Kennard-Stone algorithm. The latter set together with identical laboratory-measured 112 dry soil spectra formed a transfer dataset to develop EPO, DS and PDS correction matrices. Results showed that models after EPO, PDS and OSC corrections resulted in improved accuracy [coefficient of determination (R2) = 0.60–0.82, root mean square error (RMSE) = 16.1–5.7 g kg−1)], compared to the NC models (R2 = 0.58–0.73, RMSE = 16.5–6.8 g kg−1), whereas the DS (R2 = −0.10 to 0.26, RMSE = 26.8–21.9 g kg−1) provided deteriorated prediction accuracy. The EPO and OSC models provided better prediction accuracy than that of the PDS corrected models. The OSC-M5Rules (R2 = 0.82, RMSE = 5.7 g kg−1) obtained the highest accuracy followed by EPO-M5Rules (R2 = 0.74, RMSE = 6.7 g kg−1) and NC-M5Rules (R2 = 0.73, RMSE = 6.8 g kg−1), which outperformed all PLSR, RF and SVM models. Therefore, on-line vis-NIR spectra should be corrected with the OSC algorithm before calibrating a machine learning model for accurate prediction of SOC.
7. 题目: Formation and availability of methylmercury in mercury-contaminated sediment: effects of activated carbon and biochar amendments
期刊: Journal of Soils and Sediments
作者: Erlend Sørmo, Ludovica Silvani, Hans Fredrik Veiteberg Braaten, Tina Bryntesen, Espen Eek, Gerard Cornelissen
摘要: Purpose As the formation of toxic and bioaccumulative methylmercury (MeHg) in Hg-contaminated sediments is of great concern worldwide, suitable remediation options are needed. Activated carbon (AC) amendment is a contested alternative due to uncertainties surrounding sorption efficiency and its potential role in aiding MeHg formation. The purpose of this study was therefore to demonstrate AC performance under favourable conditions for Hg-methylation and to further understand the role AC plays in the methylation process. Materials and methods Mercury-contaminated sediment (57.1 mg kg−1) was sampled from the Gunneklev fjord, a site known as the most heavily contaminated fjord in Norway. In a laboratory experiment, lignite AC (A-AC, 5%) or activated biochar (A-BC, 5%) along with dried algae biomass, serving as an excess source of easily degradable organic matter (OM) and sulphate, were added to sediment samples that were kept anoxic and dark over a period of 12 months. Results and discussion The amount of MeHg in sediment and porewater of the amended samples were measured at 0, 1, 3, 6, and 12 months and compared to an unamended control. A net increase of MeHg in the sediment was observed in both control and amended samples, but contrary to expectations, sediment MeHg was 5 and 3 times higher in the A-AC and A-BC treatments, respectively, relative to the control after 12 months. As the stimulation of Hg-methylation could not be attributed to the sorbents supplying more available OM or sulphate for dissimilatory sulphate reduction, it is speculated that the sorbents rather aid this process through shuttling of electrons between the substrates involved. Meanwhile, the A-AC and A-BC amendments strongly reduced the available MeHg-concentration in porewater (by 87% for A-AC and by 93% for A-BC after 12 months), confirming that AC sorbents can be used to effectively limit the transport of MeHg from sediments. Conclusion When considering remediation of OM-rich Hg-contaminated sediments with AC, caution is thus warranted, as the overall effect of reducing MeHg-transport out of the sediment could partly be offset by an increased fraction of MeHg in the sediment. Thin-layer capping with AC might therefore be preferable to complete mixing of AC and sediment.
8. 题目: Exploring the potential application of hybrid permonosulfate/reactive electrochemical ceramic membrane on treating humic acid-dominant wastewater
期刊: Separation and Purification Technology
作者: Quang Viet Ly, Keyou He, Tahir Maqbool, Mingming Sun, Zhenghua Zhang
摘要: Discharge of untreated or improperly managed landfill leachate could pose a significant threat on environment due to the high strength of complex inorganic composition and abundant refractory humic acid (HA). This is the first work introducing a promising energy efficient technology using Ti4O7 anode reactive electrochemical membrane (REM) coupled with permonosulfate (PMS) to address HA-enriched wastewater. The removal performance, possible generation of reactive species along with reaction mechanisms in PMS/REM system were proposed and compared with the traditional REM system. Regardless of electrical potential, chlorine concentration, water flux and PMS dosage (with similar ionic strength by adding SO42- for REM alone), the hybrid PMS/REM system prevails the REM system alone in terms of HA degradation and energy efficiency. However, the extent of removal performance is also largely dependent upon specific condition. An increase in PMS dosage and anode electrical potential was beneficial for HA degradation, but addition of chloride imposed adverse effects on HA removal efficiency. Of those parameters, the influence of water flux on HA degradation was trivial. Compared to REM alone, in which HA was mostly removed via electrosorption, PMS/REM system, otherwise, significantly enhanced mineralization of HA. The electron paramagnetic resonance experiments demonstrated the absence of sulfate radical (SO4•-) in the PMS/REM system and implied that the more efficient performance of the hybrid system over the REM system was likely ascribed to the higher yield of hydroxyl radical (•OH). Besides, nonradical oxidation also played an important role in the PMS/REM system with the formation of a transition state of PMS molecule (PMS*), which could facilitate •OH production by inhibiting oxygen evolution site reactions.
9. 题目: Environmental photochemical fate of pesticides ametryn and imidacloprid in surface water (Paranapanema River, São Paulo, Brazil)
期刊: Environmental Science and Pollution Research
作者: Carolina Mendes Rocha, Arlen Mabel Lastre-Acosta, Marcela Prado Silva Parizi, Antonio Carlos Silva Costa Teixeira
摘要: In addition to direct photolysis studies, in this work the second-order reaction rate constants of pesticides imidacloprid (IMD) and ametryn (AMT) with hydroxyl radicals (HO●), singlet oxygen (1O2), and triplet excited states of chromophoric dissolved organic matter (3CDOM*) were determined by kinetic competition under sunlight. IMD and AMT exhibited low photolysis quantum yields: (1.23 ± 0.07) × 10-2 and (7.99 ± 1.61) × 10-3 mol Einstein-1, respectively. In contrast, reactions with HO● radicals and 3CDOM* dominate their degradation, with 1O2 exhibiting rates three to five orders of magnitude lower. The values of kIMD,HO● and kAMT,HO● were (3.51 ± 0.06) × 109 and (4.97 ± 0.37) × 109 L mol-1 s-1, respectively, while different rate constants were obtained using anthraquinone-2-sulfonate (AQ2S) or 4-carboxybenzophenone (CBBP) as CDOM proxies. For IMD this difference was significant, with kIMD,3AQ2S* = (1.02 ± 0.08) × 109 L mol-1 s-1 and kIMD,3CBBP* = (3.17 ± 0.14) × 108 L mol-1 s-1; on the contrary, the values found for AMT are close, kAMT,3AQ2S* = (8.13 ± 0.35) × 108 L mol-1 s-1 and kAMT,3CBBP* = (7.75 ± 0.80) × 108 L mol-1 s-1. Based on these results, mathematical simulations performed with the APEX model for typical levels of water constituents (NO3-, NO2-, CO32-, TOC, pH) indicate that the half-lives of these pesticides should vary between 24.1 and 18.8 days in the waters of the Paranapanema River (São Paulo, Brazil), which can therefore be impacted by intensive agricultural activity in the region.
10. 题目: Characteristics of dissolved organic matter in surface water and sediment and its ecological indication in a typical mining-affected river—Le’an River, China
期刊: Environmental Science and Pollution Research
作者: Wenhui Liu, Teng Ma, Yao Du, Xiancang Wu, Liuzhu Chen, Junqi Li
摘要: Dissolved organic matter (DOM) plays an important role in the cycling and toxicity of heavy metals in aquatic systems. However, most studies have focused only on DOM in either water or sediments. This study aimed to analyze the source, composition, and structural characteristics of DOM in both surface water and bottom sediments of the Le'an River and its major tributaries. In addition, the potential ecological risks of three typical heavy metals (Cu, Pb, and Zn) were quantitatively evaluated based on the characteristics of DOM and in situ data. The results showed that sediment DOM is more aromatic and hydrophobic than surface water DOM. Although humic-like components dominated the DOM pool in both surface water and sediments, their sources were different. Surface water DOM is mainly autochthonous, while sediment DOM is controlled by both autochthonous and allochthonous sources. Risk prediction results based on DOM characteristics show that surface water has a higher potential risk of heavy metal release than sediments. Comprehensively considering the ecological risk of water and sediments, high-risk areas were found to be mainly distributed in the upper and middle reaches of the Le'an River. This distribution is attributable to the developed mining and smelting industries in these areas and consistent with the risk assessment results of measured concentrations of heavy metals. This study established a new technique for predicting the ecological risk of aquatic systems based on the characteristics of DOM in surface water and sediments.
11. 题目: Functionalized porous nanoscale Fe3O4 particles supported biochar from peanut shell for Pb(II) ions removal from landscape wastewater
期刊: Environmental Science and Pollution Research
作者: Xiaojun Jin, Renrong Liu, Huifang Wang, Li Han, Muqing Qiu, Baowei Hu
摘要: The large amounts ofheavy metal from landscape wastewater have become serious problems of environmental pollution and risks for human health. The development of efficient novel adsorbent is a very important for treatment of heavy metal. The functionalized porous nanoscale Fe3O4 particles supported biochar from peanut shell (PS-Fe3O4) for removal of Pb(II) ions from aqueous solution was investigated. The characterization of PS-Fe3O4 composites showed that biochar was successfully coated with porous nanoscale Fe3O4 particles. The pseudo second-order kinetic model and Langmuir model were more fitted for describing the adsorption process of Pb(II) ions in solution. The adsorption process of Pb(II) ions removal by PS-Fe3O4 composites was a spontaneous and endothermic process. The adsorption mechanisms of Pb(II) ions by PS-Fe3O4 composites were mainly controlled by the chemical adsorption process. The maximum adsorption capacity of Pb(II) ions removal in solution by PS-Fe3O4 composites reached 188.68 mg/g. The removal mechanism included Fe-O coordination reaction, co-precipitation, complexation reaction, and ion exchange. PS-Fe3O4 composites were thought as a low-cost, good regeneration performance, and high efficiency adsorption material for removal of Pb(II) ions in solution.
12. 题目: Accumulation and release of organic phosphorus (P) from legacy P-affected soils to adjacent drainage water
期刊: Environmental Science and Pollution Research
作者: Suwei Xu, Nicolas F. Martin, Jeffrey W. Matthews, Yuji Arai
摘要: Legacy effects of P in agricultural soils have been highlighted in recent literature. However, co-accumulation and release of organic P (Po) have often been ignored in current agro-environmental assessments. The mineralizable Po fraction has a potential to increase the activity of phosphate in pore water, increasing fertility or degrading water quality. In this study, the effects of agricultural management practices (fertilizer applied corn-soybean rotation cropland and dairy manure applied pasture) on the Po/phosphate ratio were investigated in P-rich (290-1232 mg kg-1) agricultural soils and adjacent ditchwater using experimental soil-water chemistry. The effect of agricultural management was significant on both Po and the Po/phosphate ratio in soil and adjacent ditchwater. The Po content, dominated by orthophosphate monoesters, in the manure-amended pasture (average ~ 245 mg kg-1) was significantly greater than that in the fertilizer-applied cropland (average 103 mg kg-1). The Po/phosphate ratio was also significantly greater in the manure-amended pasture (0.54) than in the fertilizer-applied cropland (0.42). Similarly, water quality data also showed that ditchwater near the pasture had a significantly greater flux of dissolved non-reactive P and a greater Po/phosphate ratio compared to the water near the fertilizer-applied sites. Furthermore, a greater Po/phosphate ratio in ditchwater was often observed during wet periods, and the ratio was positively correlated to the discharge (r = 0.42, p = 0.003). The study showed the agricultural management-specific Po accumulation and release and - Po/phosphate ratio that might affect the fate of P in agroecosystems.
13. 题目: Novel insight into dissolved organic nitrogen (DON) transformation along wastewater treatment processes with special emphasis on endogenous-source DON
期刊: Environmental Research
作者: Kewei Liao, Haidong Hu, Jinfeng Wang, Bing Wu, Hongqiang Ren
摘要: Knowledge of endogenous-source dissolved organic nitrogen (esDON) produced in wastewater treatment processes is critical for evaluating its potential impacts on receiving waters because esDON is a recognized concern, as it causes eutrophication. However, differentiating esDON from influent residual DON in real wastewater is always a challenge. Here, we deciphered esDON information in DON transformation processes along a full-scale wastewater treatment train by combining multiple chemometric tools with ion-mobility separation quadrupole time-of-flight mass spectrometry (IMS-QTOF MS) analyses. In total, DON became more refractory and compact with shorter carbon chains and fewer nitrogen atoms, and esDON composed a nonnegligible fraction that dominated DON transformation and characteristics. New esDON produced in treatment processes constituted a crucial part (>35.5%) of wastewater DON, and its contributions to wastewater DON are augmented along the train. Evidence of molecular conformations further confirmed dominant roles of esDON in DON characteristics. Moreover, esDON participated in 46.7% of core biochemical reaction networks, explaining the importance of esDON in DON transformation. Our study offers a tool to gain esDON characteristics and transformation mechanisms, and highlights the importance to control esDON for alleviating adverse influences from DON in receiving waters.
14. 题目: Wet wastes to bioenergy and biochar: A critical review with future perspectives
期刊: Science of The Total Environment
作者: Jie Li, Lanyu Li, Manu Suvarna, Lanjia Pan, Meisam Tabatabaei, Yong Sik Ok, Xiaonan Wang
摘要: The ever-increasing rise in the global population coupled with rapid urbanization demands considerable consumption of fossil fuel, food, and water. This in turn leads to energy depletion, greenhouse gas emissions and wet wastes generation (including food waste, animal manure, and sewage sludge). Conversion of the wet wastes to bioenergy and biochar is a promising approach to mitigate wastes, emissions and energy depletion, and simultaneously promotes sustainability and circular economy. In this study, various conversion technologies for transformation of wet wastes to bioenergy and biochar, including anaerobic digestion, gasification, incineration, hydrothermal carbonization, hydrothermal liquefaction, slow and fast pyrolysis, are comprehensively reviewed. The technological challenges impeding the widespread adoption of these wet waste conversion technologies are critically examined. Eventually, the study presents insightful recommendations for the technological advancements and wider acceptance of these processes by establishing a hierarchy of factors dictating their performance. These include: i) life-cycle assessment of these conversion technologies with the consideration of reactor design and catalyst utilization from lab to plant level; ii) process intensification by integrating one or more of the wet waste conversion technologies for improved performance and sustainability; and iii) emerging machine learning modeling is a promising strategy to aid the product characterization and optimization of system design for the specific to the bioenergy or biochar application.
15. 题目: Simultaneous bio-reduction of nitrate and Cr(VI) by mechanical milling activated corn straw
期刊: Journal of Hazardous Materials
作者: Yutian Hu, Tong Liu, Nan Chen, Chuanping Feng, Wang Lu, Huaming Guo
摘要: Abundant lignocellulose waste is an ideal energy source for environmental bioremediation, but its recalcitrance to bioavailability makes this a challenging prospect. We hypothesized that the disruption of straw’s recalcitrant structure by mechanochemical ball milling would enhance its availability for the simultaneous bioreduction of nitrate and Cr(VI). The results showed that the ball-milling process increased the quantity of water-soluble organic matter released from corn straw and changed the composition of organic matter by strongly disrupting its lignocellulose structure. The increase in ball-milling time increased the specific surface area of the straw and favored the adhesion of microorganisms on the straw surface, which enhanced the bioavailability of the energy in the straw. Substantially increased removal of NO3--N (206.47±0.67mg/g) and Cr(VI) (37.62±0.09mg/g) was achieved by using straw that was ball milled for 240min, which validated that ball milling can improve the utilization efficiency of straw by microorganisms. Cellular and molecular biological analyses showed that ball-milled straw increased microbial energy metabolism and cellular activity related to the electron transport chain. This work offers a potential way to achieve the win-win goal of utilizing agricultural wastes and remediating environmental pollution.
16. 题目: Interactions of anthropogenic and terrestrial sources drive the varying trends in molecular chemodiversity profiles of DOM in urban storm runoff, compared to land use patterns
期刊: Science of The Total Environment
作者: Yi Zhu, Hao Chen, Qilong Jia, Hui Liu, Jianfeng Ye
摘要: Variations in land use drive the heterogeneous nature of dissolved organic matter (DOM) in storm runoff. However, in the context of the currently complicated multifactor interactions of urban land use, contamination occurrence, and environmental management, it is unclear how the molecular chemodiversity of storm runoff DOM responds to land use patterns or potential anthropogenic sources. Using Fourier-transform ion cyclotron resonance mass spectrometry, this study evaluated the molecular chemodiversity profiles of DOM in urban storm runoff from different land use and underlying surface pavement combinations. The chemodiversity of suburban forest runoff-associated DOM was characterized by high lignin and tannin abundance, predominance of CHO molecules, less heteroatoms, high molecular mass, and highly unsaturated and aromatic compounds. Urban storm runoff-associated DOM was predominantly characterized by abundant lipids, proteins, and carbohydrates, low-mass molecules, abundant S- and P-bearing heteroatoms, and high saturation. The low conformity of unique molecular features co-occurring across urban land-uses suggests a relatively incohesive pool in the urban storm runoff-associated DOM, i.e., high chemodiversity. The reconstructed source-derived patterns significantly drive the directional trends in DOM of urban storm runoff, oppositely shifting toward high saturation vs. high unsaturation and aromatization features. This demonstrates that unveiling the interactions of anthropogenic and terrestrial sources in order to understand the underlying mechanism is critical for our ability to track and predict the current and future turnover in DOM chemodiversity in storm runoff in the context of the global trend of upgrading urban environment management, following recognition of their probable links with urban land-uses. Underlying surface pavement can hardly superimpose a directional effect to alter the discrepancies in the dominant molecules of each urban land use further. These findings reveal the importance of understanding DOM characteristics at a molecular level and potentially enable targeted control of ecological risks in receiving ecosystems induced by urban storm runoff.
17. 题目: The broad application and mechanism of humic acids for treating environmental pollutants: Insights from bibliometric analysis
期刊: Journal of Cleaner Production
作者: Pengfei Xu, Xiaoling Zhu, Huashang Tian, Guangxu Zhao, Yuxia Chi, Baolei Jia, Jie Zhang
摘要: Humic acids (HAs) are macromolecular substances that play important roles in different areas of soil, atmosphere, water, and ecological environment restoration. Here, we applied bibliometric analysis to systematically evaluate HAs applications in the environmental field. In-depth analysis of the publication characteristics of 9145 articles published from 1980 to 2020 revealed that the number of articles published on HAs increased rapidly, with China having the largest number of publications (3109), followed by the United States (1949) and Germany (679). Specifically, the Chinese Academy of Sciences had the largest number of publications (647) and was the center of the most productive institutional cooperation network. HAs applications and mechanisms for treating organic pollutants and heavy metals are important research topics in the environmental field. HAs could reduce the toxicity of a variety of organic pollutants or eliminate pollutants through photodegradation and adsorption. These pollutants include antibiotics, herbicides pesticides, fungicides, and other phenolic compounds. Additionally, HAs might be also used to treat heavy metal pollutants, such as mercury, copper, cadmium, uranium, and aluminum. HAs could adsorb heavy metals, thereby reducing their mobility in the environment and toxicity. HAs also have the potential to degrade microplastics and contribute to climate change adaptation. However, bibliometric analysis showed that the molecular structure of HAs remains unclear, thereby limiting clarification of mechanisms and further applications for decontamination. These findings highlight the interaction between HAs and the environment and offer critical insight to support further development of HAs for environmental applications.
18. 题目: The characterization of organic nitrogen and sulfur functional groups in coals after biomethane production
期刊: Environmental Science and Pollution Research
作者: Xile Liu, Fenghua Zhao, Hongyu Guo, Daping Xia, Zhiwei Dong, Zhiheng Li
摘要: To study the change characteristics of nitrogen and sulfur functional types in the raw coal and coal residues after anaerobic fermentation, three different rank coals from Baiyinhua mine (BY coal), Qianqiu mine (QQ coal), and Malan mine (ML coal) in China were collected and treated with methanogenic microorganisms, then X-ray photoelectron spectroscopy (XPS) was used to test the nitrogen and sulfur functional types in raw coals and coal residues. The results show that the pyrrolic nitrogen (N-5) and aromatic sulfur are the main nitrogen type and sulfur type in three coals. The N-5 increases by 17.42% in BY coal residue and decreases by 2.37% and 8.51% in QQ and ML coal residues, respectively. The pyridinic nitrogen (N-6) in BY, QQ, and ML coal residues decreases by 2.18%, 5.44%, and 2.75%, respectively. The aromatic sulfur increases by 2.13%, 3.14%, and 4.02% in BY, QQ, and ML coal residues, respectively. The aliphatic sulfur has obvious changes in BY and QQ coal residues with the increment of 9.17% and decrement of 11.64%, respectively. The results reveal that the nitrogen and sulfur types have changed in the coal residues after the biomethane production, and the instable types such as N-5 and aliphatic sulfur have obvious changes in the low-rank BY and QQ coals. The research provides a sight to the changes about nitrogen and sulfur types after biomethane yield and more deep thoughts about the clean and effective utilization of coals.
19. 题目: Changes in soil moisture and organic carbon under deep-rooted trees of different stand ages on the Chinese Loess Plateau
期刊: Agriculture, Ecosystems & Environment
作者: Fan Yang, Mingbin Huang, Chenhui Li, Xiaofei Wu, Tianqi Guo, Miyuan Zhu
摘要: Deep-rooted plants have increasingly been introduced after cropland abandonment with the implementation of the ‘Grain-for-Green’ program on the Chinese Loess Plateau (CLP). However, the temporal patterns of soil moisture content (SMC) and soil organic carbon (SOC) with stand ages and the potential role of deep roots driving these patterns within deep profiles are still poorly understood. Here, we investigated variations in fine root distribution, SMC, and SOC content and density in 0–500 cm soil profiles under two deep-rooted plant systems with different stand ages (black locust plantation, Robinia pseudoacacia L.; and apple orchard, Malus pumila Mill.), evaluated their soil moisture deficit (SMD) and SOC sequestration effect relative to cropland, and attempted to characterize the role of deep roots in driving these variations. The results confirmed severe SMD in all soil layers within the 0–500 cm profile under black locust plantations, relative to cropland, but noting some SMC recovery under the 38-year-old black locust plantation. In contrast, depth-averaged (0–500 cm) SMC increased notably during the initial 5 years and then declined continuously over time under apple orchards. These results suggest the temporal pattern of SMC varies with deep-rooted systems. The SOC density of the 100–500 cm layer accounted for more than half of the entire profile, and SOC accumulation mostly occurred at depths below 300 cm under the two deep-rooted systems, which indicates the great importance of deep soils for carbon sequestration. The temporal patterns of deep SOC were different from those in surface soils. Obvious carbon losses were detected within the 20–500 cm soil profile under the 38-year-old black locust plantation. The linkages between SMC and SOC content were typically stronger under black locust plantations than under apple orchards. The influence of roots on SMC was stronger under apple orchards than under black locust plantations. Suitable land management practices are recommended to restore the fragile ecosystem of the CLP. Overall, our findings provide new insights for sustainable vegetation restoration in restored ecosystems.
20. 题目: Low molecular weight organic acids strengthen the electron transfer of natural FeS2/biochar composite for Cr(VI) reduction: Experimental observations and governing mechanisms
期刊: Journal of Environmental Chemical Engineering
作者: Beibei Zhao, Jingchun Tang, Honghong Lyu, Feng Liu, Lan Wang
摘要: Low molecular weight organic acids with low cost and environmentally friendly characteristics can enhance the electron transfer between materials and contaminants. In this study, oxalic acid (OA), citric acid (CA), and ethylenediaminetetraacetic acid (EDTA) were selected to strengthen ball milled natural FeS2/biochar composite (FeS2/biochar) for aqueous Cr(VI) removal. 100% of Cr(VI) was removed when 5mM of OA and 0.25g·L-1 FeS2/biochar were used together. In contrast, the removal rate of Cr(VI) by the individual FeS2/biochar and OA was 57.9% and 6.3%, respectively. The experimental and characterization results suggested that OA was adsorbed on the surface of FeS2/biochar through the conjugated structure of pine biochar, thereby enhancing the dissolution rate of Fe(II) and S(-II) in the FeS2/biochar composite, and facilitating the conversion of Fe(II), S(-II), and Cr(VI) to Fe(III), SO42-, and Cr(III), respectively. In addition, the complexation of OA with Fe(III) and Cr(III) reduced the formation of Fe(OH)3 and Cr(OH)3, exposing more surface active site of FeS2/biochar for the reduction of Cr(VI). As an electron donor, the addition of OA enhanced the electron transfer process of FeS2/biochar to Cr(VI) on the one hand, and on the other hand promoted the redox cycle of Fe(II) through the electron transfer between OA and Fe ions. FeS2/biochar showed better stability even after 5 cycles (in 5mM OA system). The present study demonstrated the promise of low molecular weight organic acids in strengthening materials for environmental remediation.