UV/Fe3+ and persulfate are two promising advanced oxidative degradation systems for in situ remediation of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), yet a lack of comprehensive understanding of the degradation mechanisms. For the first time, we used density functional theory (DFT) to calculate the entire reaction pathways of the degradation of PFOA/PFOS in water by UV/Fe3+ and persulfate. In addition, we have deeply explored the different attack pathways driven by •OH and SO4−•, and found that SO4−• determines PFOA/PFOS to obtain PFOA/PFOS free radicals through single electron transfer to initiate the degradation reaction, while •OH determines the speed of PFOA/PFOS degradation reaction. Both degradation reactions were thermodynamically advantageous and kinetically feasible under calculated conditions. Based on the thermodynamic data, persulfate was found to be more favorable for the advanced oxidative degradation of Perfluorinated compounds (PFCs). Moreover, for SO4−• and •OH co-existing in the persulfate system, pH will affect the presence and concentration of these two types of free radicals, and low pH is not necessary for the degradation of PFOA/PFOS in the persulfate system. These results can considerably advance our understanding of the PFOA/PFOS degradation process in advanced oxidation processes (AOPs), which is driven by •OH and SO4−•. This study provides a DFT calculation process for the mechanism calculation of advanced oxidation degradation of other types of PFCs pollutants, hoping to elucidate the future development of PFCs removal. Further research should focus on determining the advanced oxidation degradation pathways of other types of PFCs, to support the development of computational studies on the advanced oxidation degradation of PFCs.

To develop new radical synthesis strategies, a profound understanding of the electronic transfer mechanism is critical. An activation model called relayed proton-coupled electron transfer (relayed-PCET) was developed and investigated for chiral phosphoric acid-catalyzed diradical reactions by density functional theory (DFT). The driving force of electron transfer from the nucleophile to the electrophile is the proton transfer that occurs via the chiral phosphoric acid (CPA) catalyst to the electrophile. Moreover, the origins of the selectivity can be explained by distortion of the catalyst, favorable hydrogen bonding, and strong interactions of the substrates with substituents of the CPAs.

The application of clean energy is one effective way to alleviate the economy’s dependence on fossil energy while reducing greenhouse gas (GHG) emissions. However, the complementary and synergistic effects of environmental policy in clean energy promotion remain controversial. This paper aims to investigate the role of structural carbon taxes and clean energy subsidies in low carbon transition. Heterogeneous environmental dynamic stochastic general equilibrium (E-DSGE) approach with firm heterogeneity is applied to describe the impact path of structural environmental policy on China’s environmental-economic system. The results show that the structural carbon emission reduction policy has synergistic effects and can balance the relationship between energy demand and economic growth. Furthermore, distinguishing production technology and green innovation technology can promote energy-saving enterprises and improve the industrial structure. This paper might be the first attempt to discuss the synergistic effects of climate policy based on heterogeneous E-DSGE model.

In recent years, the environmental pollution of microplastics has attracted much attention. To date, there have been a lot of researches on microplastics and a series of studies published. In this study, by bibliometric analysis method to evaluated the development and evolution on microplastics research trends and hot spots. A total of 2872 literature information was collected from the Web of Science (2004-2020), which was used for bibliometric visual analysis by CiteSpace. It was possible to see the contributing countries, institutions, authors, keywords, and future study directions in the microplastics sectors by looking at the visual representation of the results. (1) Since 2004, scientific advancements in this sector have advanced significantly, with a significant increase in speed since 2012. (2) China and the United States are the world's leading researchers in microplastics. (3) The study of microplastics was multidisciplinary, comprising researchers from the fields of ecology, chemistry, molecular biology, environmental science, and oceanography. (4) In recent years, researchers have concentrated their attention on the distribution and toxicity of microplastics in the environment, as well as their coupled pollution with heavy metal contaminants. In conclusion microplastics study in environmental science has become increasingly popular in recent years. Topics include dispersion, toxicity, and coupled pollution with heavy metal pollutants. Researchers in a wide range of fields are involved in microplastics research. Furthermore, policies and regulations about microplastics in global were summarized, and membrane technology has potential to remove microplastics from water. The above findings help to clearly grasp the content and development trend of microplastics research, point out the future research direction for scholars, and promote microplastics research and pollution prevention and control.

水资源是生态系统中最重要的因子,加强水资源环境保护是加快建设生态文明和美丽中国的要求.研究经济社会发展进程中的水资源环境状态,对地区生态文明建设与可持续发展具有重要的理论与实践意义.基于DPSIR模型建立水资源承载力评价指标体系,针对现有综合评价研究在赋权方面的单一性,采用DS证据理论思想,融合独立度、非均衡度、贡献度及灵敏度属性信息进行指标赋权;采用熵值法与灰色关联法进行时间集成赋权.在此基础上,通过构建距离贴近度与方向贴合度的改进TOPSIS模型,测算2009—2018年长江经济带11个省份的水资源承载力.结果显示:长江经济带11个省份间水资源承载力地区发展不均衡,空间差异显著,整体呈现下游地区大于上游地区,上游地区大于中游地区的特点,下游长三角地区及上游川渝地区表现最优,进一步表明实证模型的科学性与适用性.为促进长江经济带水资源承载力协调发展,各地区应因地制宜,依据地区实际经济社会与地理环境,对水资源进行科学保护与管理.

In recent decades, most countries have implemented environmental protection by formulating relevant environmental regulations to reduce environmental pollution and improve environmental quality. China enacted new Environmental Protection Tax Law in 2018 and abolished the old system of pollution discharge fees. This paper analyzes and predicts the effectiveness of these new environmental tax policies within the framework of a macroeconometric dynamic stochastic general equilibrium (DSGE) model. Bayesian estimation is applied to estimate dynamic parameters based on China’s macroeconomic data from 1978 to 2018. We find that the implementation of China’s new environmental tax will lead to a significant increase in environmental quality through a reduction in the amount of pollution. However, the study reveals that new environmental taxes may have certain negative influences on economic growth. Consumption, output, wages, and capital could fall by 1.26%, 0.34%, 1.16%, and 1.12%, respectively, which may slow the pace of China’s development.

A disposable electrochemical sensor (ES) was developed by embellishing graphene on carbon paste electrode (CPE), and the electrocatalytic activity of fluoranthene (Frt) was investigated. An anodic peak of Frt-acetonitrile-NaClO4 appeared at 1.6 V based on the cyclic voltammetry. The peak current of Frt at graphene-modified CPE was increased compared with that of unmodified electrode. The differential pulse voltammetry revealed a linear relationship between peak current and Frt concentration within 2–140 ng mL-1, and the LOD was calculated to be 0.95 ng mL-1. Also, the ES method was effective for rapid determination of Frt in black rubbers on modified CPE.

Designing and fabricating high-powered Z-scheme photocatalysts are highly desired to improve the visible-light activity for efficiently degrading organic pollutants. In this work, a novel all-solid-state Ag bridged BiVO4/ZnIn2S4 (BiVO4/Ag/ZnIn2S4) core-shell structure Z-scheme nanocomposite is constructed by multi-step solvothermal method with in-situ growth, in which the degradation rate of 2,4-DCP is 4 times than that of BiVO4 within 3 h. On the basis of Valence Band-X-ray photoelectron spectroscopy (VB-XPS) spectra, Kelvin probe force microscopy, single-wavelength photoactivities and DMPO spin-trapping electron para-magnetic resonance (EPR) spectra, the exceptional photoactivities of BiVO4/ZnIn2S4 core-shell structure is mainly attributed to the Z-scheme mechanism of BiVO4/ZnIn2S4 exhibits significant effect on the promotion of photogenerated charge separation within the system. Excitingly, it has been proved that the photo-generated charge of Z-scheme mechanism can be further effectively separated by introducing Ag bridges between BiVO4 and ZnIn2S4, as supported by photophysical, photochemical and photoelectrochemical tests. In practice, this work provides valuable experience for develop new core-shell structure BiVO(4)(-)based narrow band gap photocatalysts for organic degradation. In theory, it further reveals the photogenerated transfer mechanism and improvement paths in the Z-scheme system. (C) 2021 Elsevier B.V. All rights reserved.

采用自相关分析和累计信息贡献率法,对经济发展和环境质量评价指标进行二次筛选,构建综合评价指标体系;基于熵值法、TOPSIS法和灰色关联度法,计算经济和环境系统历年单一评价值;采用支持度模型进行综合评价,得到经济与环境系统的动态综合评价值;引入耦合协调度模型,对30个省域2008-2017年的经济发展与环境质量的耦合协调发展进行评级,为各省域协调发展提供决策支持.

It is crucial to tune the morphology of aggregates to obtain functional photoelectric properties in perylene bisimide (PBI). The associated properties can be controlled by appropriate molecular design and by tuning the self-assembly conditions. However, many studies only focused on the modification with easily-protonated groups at the bay positions of perylene bisimide, which greatly limited their potential applications. In this work, four PBI derivates bearing tertiary amine groups at the imide positions were synthesized and their self-assembly with different concentrations of hydrochloric acid were performed. The final morphology and the properties of the aggregates were tuned by modifying the charge interaction in addition to π-π stacking and hydrophobic interactions. The evolution of the specific morphology with the acidity of the self-assembly conditions was discussed and the molecular structure was optimized. The photophysical properties of the aggregates were characterized by UV–visible and fluorescence spectroscopy. The shapes of the spectra varied with the molecular structures and the acid concentration. Moreover, the emission spectra of the aggregates experienced a large Stokes shift. The color of the aggregates formed from the three derivates (MDI-PBI, EDI-PBI, and AEP-PBI) changed from red to blue upon protonation. These derivatives may have potential applications in organic photoelectric functional devices where a strict morphology or size is needed. The protonation-dependent morphology, the color change, and the large Stokes shift makes the aggregates potential candidate for fluorescent probes or pH sensors.

In this work, perylene bisimide derivatives (PBI-1 and PBI-2) with tertiary amine groups were designed and synthesized. To control the final morphologies and properties of their aggregates, seven kinds of organic acids were used to alter the self-assembly environment. The influence of organic acids on the morphology of the aggregates was investigated. Photophysical properties of the aggregates were markedly affected by the kind and concentration of the organic acid. The thermal and gas sensitivities of the PBI-1 aggregates were studied with the use of UV–visible spectroscopy and digital imaging. The shift of the UV–visible spectra varied with time, temperature, acid type and acid concentration. Furthermore, PBI-1 aggregates showed a red-to-blue color change after addition of seven organic acids, whereas the color of the PBI-2 aggregates remained red. These changes of morphologies, photophysical properties and their thermal and gas sensitivities make these aggregates potentially useful in the fields of optoelectronics or sensors.

The degradation of the artificial sweetener acesulfame (ACE) was investigated using an ultraviolet (UV)365-activated peroxydisulfate (PDS) process. The results demonstrated that the ACE reaction rate with the UV/PDS process followed pseudo first-order kinetics (R2 > 0.9) under various conditions. A high dosage of PDS, alkaline condition, and the existence of NO3- and Cl- enhanced ACE degradation; however, a high dosage of ACE, the existence of HCO3-, humic acid, and fulvic acid, and a real water matrix did not facilitate the degradation of ACE. Four types of transformation products were detected in the degradation of ACE by UV/PDS, and the primary degradation pathways were oxidation, hydroxyl substitution, hydrolysis, and hydration. The hydroxyl radicals played a predominant role (71.31%) in the degradation of ACE by the UV/PDS process, followed by sulfate radicals (14.57%) and UV photolysis (8.83%). Both the degradation and mineralization rates of ACE using the UV/PDS process had significant advantages over that of the UV/H2O2 process regarding ACE degradation, indicating that the UV/PDS process is more promising for treating water containing ACE.

The disadvantages of high cost, easy poisoning and insufficient durability hinder platinum (Pt) application in direct methanol fuel cells. In this study, a hybrid of reduced graphene oxide/carbon nanotubes-supported hollow copper spheres (Cu/rGO@CNTs) is prepared by a one-step electrodeposition method. Then, the internal and external surfaces of hollow Cu spheres are coated with Pt skims to obtain a hollow bimetallic electrocatalyst (Pt/Cu/rGO@CNTs) through a simple galvanic replacement reaction by immersing Cu/rGO@CNTs in a chloroplatinic acid (H2PtCl6) solution. The three dimensional rGO@CNTs network structure benefit mass transport and electron transfer. Pt skims expose abundant active sites for electrocatalytic methanol oxidation reactions (MORs). Cu cores synergize Pt skims to enhance anti-poison ability. As a result, Pt/Cu/rGO@CNTs shows an excellent electrocatalytic activity for MORs with a robust tolerance of catalyst poisoning. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

The effects of low-molecular-weight organic acids (LMWOAs) on the transport of graphene oxide nanoparticles in saturated kaolinite- and goethite-coated sand columns were studied. Acetic acid, glycolic acid, malonic acid, and tartaric acid were chosen in the experiments. LMWOAs enhanced the mobility of GO by electrostatic/steric repulsion. In addition, they competed with GO for limited deposition sites on grain surfaces. The effects of organic acids on the transport of GO strongly depended on organic acid species. In general, the transport enhancement effects followed the order of tartaric acid > malonic acid > glycolic acid > acetic acid; this difference may be related to the number and type of functional groups of organic acids. Different LMWOAs enhanced the transport of GO in goethite-coated sand to a larger extent than did in kaolinite-coated sand under the test conditions; this was likely related to the differences of physicochemical characteristics between goethite and kaolinite. Organic acids significantly inhibited the deposition of GO at 0.5 mM Ca 2+ ; this was possible that Ca 2+ enhanced adsorption of organic acids by complexing with the surface O-functionalities of both LMWOAs and sand grain. Consequently, more organic acid molecules competed with GO for deposition sites on grain surfaces. Additionally, a two-site transport model was used to fit the transport data. Our findings have important implications for the understanding of the deposition and fate of GO in soil especially in rhizosphere environments where various low-molecular-weight organic acids are active.

The evaluation target was 30 provinces from 2010 to 2015. The eco-environmental quality index system was established by the "driving-force-pressure-state-impact-response" framework. The index weight was defined by vertical and horizontal layer by layer scatter degree method, and the time weight was calculated by concept of "time-degree" and "entropy value" method. The dynamic evaluation model of eco-environmental quality was constructed by TOWA-GA hybrid operator. The results indicated that: The total average of the ecological quality of the 30provinces was 0.837 and the overall trend was positive in the past six years, but there were significant differences between provinces. Analysis by Theil index showed that: The overall difference between provinces had dropped by 15.9％, and the population density and natural population growth rate were the main factors of differences between provinces.

In view of the complexity of the urban environmental quality evaluation and the limitation of the static evaluation approaches, this paper is inclined to introduce a dynamic evaluation method for assessing the urban environmental qualities. The improved TOPSIS model we have proposed has been founded on the basis of the double-weighted indexes,the index weight and the time weight in answering to the multi-dimensional indexical systems. To formulate and improve the model mentioned above,we have to first of all do a comprehensive analysis of the influential factors of the quality and quantity of the urban environment so as to establish an environment assessment indexical system including the one first-grade index,the four second-level indexes of the atmospheric environment,i. e. the environment noise,the solid environment wastes,the quality of water and the ecological environment with eleven 3-rd-level indexes. And,then,it is necessary to assess objectively the evaluation indexes of the Environmental quality by the improved CRITIC method,which can help to obtain the weighted environmental indicators. At the same time,particular stress has to be given to the weight of time dimension by using the evaluation standard of " emphasizing the present rather than the past " when problem is concerned with the different time points. In addition,it is also necessary to add the index weight and time weight when taking into account the influence of time dimension on the evaluation results,so as to normalize the TOPSIS model,and do the weighted processing via the decision matrix and the increment matrix. And,finally,it is also necessary to apply the absolute and relative indicators to the dynamic evaluation of the regional environmental quality so as to and obtain the ranks of the different urban environmental qualities and the development status-in-situ of the environmental qualities at different stages. Thus,all the empirical results of the 30 provincial capitals in the period from 2011 to 2015 show that the improved TOPSIS model can reasonably reflect the dynamic situation of the urban Environmental quality,and can in turn verify the feasibility of the evaluation method. What is more,the evaluation results can also serve as the reliable foundation for the environmental management policy making.

针对以往大气环境评价指标赋权的主观性、仅注重个体或整体而忽略彼此联系,文章提出用变异系数改进的CRITIC法和超标倍数法集成的指标权重;针对大气环境系统的模糊性和不确定性,采用模糊优选法对南京市2003-2013年大气环境进行评价,克服了以往模糊评价中隶属函数选择主观性,实现了不同年份和标准等级的大气质量同时排序.

Two new compounds isobenzofuranone A (1) and indandione B (2), together with eleven known compounds (3–13) were isolated from liquid cultures of an endophytic fungus Alternaria sp., which was obtained from the medicinal plant Morinda officinalis. Among them, the indandione (2) showed a rarely occurring indanone skeleton in natural products. Their structures were elucidated mainly on the basis of extensive spectroscopic data analysis. All of the compounds were evaluated with cytotoxic and α-glucosidase inhibitory activity assays. Compounds 11 and 12 showed significant inhibitory activities against four tumor cell lines; MCF-7, HepG-2, NCI-H460 and SF-268, with IC50 values in the range of 1.91–9.67 μM, and compounds 4, 5, 9, 10, 12 and 13 showed excellent inhibitory activities against α-glucosidase with IC50 values in the range of 12.05–166.13 μM.

In this study, a paper spray ionization mass spectrometric (PS-MS) method was developed for the rapid in situ screening and simultaneous quantitative analysis of bisphenol A and its analogues, i.e., bisphenol S, bisphenol F, and bisphenol AF, in food packaging products. At the optimal PS-MS conditions, the calibration curves of bisphenols in the range of 1-100 μg/mL were linear. The correlation coefficients were higher than 0.998, and the LODs of the target compounds were 0.1-0.3 μg/mL. After a simple treatment by dichloromethane on the surface, the samples were analyzed by PS-MS in situ for rapid screening without a traditional sample pretreatment procedure, such as powdering, extraction, and enrichment steps. The analytical time of the PS-MS method was less than 1 min. In comparison with conventional HPLC-MS/MS, it was demonstrated that PS-MS was a more effective high-throughput screening and quantitative analysis method.

A three-dimensional (3D) reduced graphene oxide Mn3O4 nanosheet (Mn3O4@rGO) hybrid was achieved by simple electrodeposition technique. Small palladium nanoparticle were homogeneously anchored onto Mn3O4@rGO substrate through the reduction of palladium salt. The interpenetrating network architecture of Mn3O4@rGO greatly inhibited the aggregation of 2D sheets of Mn3O4 and rGO, and the open 3D orientation of the Mn3O4 rGO hybrid nanosheets on the electrode facilitated both mass transport and electron transfer as well as maximally exposed active sites. The introduction of Mn3O4 enhanced the structural and electrochemical stability of rGO. The as-synthesized Pd/Mn3O4 rGO hybrid was employed as an electrocatalyst for electrocatalytic hydrogen evolution reaction (HER). The electrocatalyst showed a low overpotential of 20 mV at 10 mA cm(-2), a small Tafel slope of 48.2 mV dec(-1), and a large exchange current density of 0.59 mA cm(-2). Importantly, the catalyst possessed superior durability with 85.87% of catalytic activity after a long-time test (10 h). This work presents a simple and efficient stratagy to construct high-performance electrocatalysts for energy and environmental applications. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.