Effect of sulfur source on photocatalytic degradation performance of CdS/MoS2 prepared with one-step hydrothermal synthesis

Cd S/Mo S_2,an extremely efficient photocatalyst,has been extensively used in hydrogen photoproduction and pollutant degradation.Cd S/Mo S_2can be synthesized by a facile one-step hydrothermal process.However,the effect of the sulfur source on the synthesis of Cd S/Mo S_2via one-step hydrothermal methods has seldom been investigated.We report herein a series of one-step hydrothermal preparations of Cd S/Mo S_2using three different sulfur sources:thioacetamide,L-cysteine,and thiourea.The results revealed that the sulfur source strongly affected the crystallization,morphology,elemental composition and ultraviolet(UV)–visible-light-absorption ability of the Cd S/Mo S_2.Among the investigated sulfur sources,thioacetamide provided the highest visible-light absorption ability for Cd S/Mo S_2,with the smallest average particle size and largest surface area,resulting in the highest efficiency in Methylene Blue(MB)degradation.The photocatalytic activity of Cd S/Mo S_2synthesized from the three sulfur sources can be arranged in the following order:thioacetamideL-cysteinethiourea.The reaction rate constants(k)for thioacetamide,L-cysteine,and thiourea were estimated to be 0.0197,0.0140,and 0.0084 min~(-1),respectively.However,thioacetamide may be limited in practical application in terms of its price and toxicity,while L-cysteine is relatively economical,less toxic and exhibited good photocatalytic degradation performance toward MB.     

Managed grassland alters soil N dynamics and N2O emissions in temperate steppe

Reclamation of degraded grasslands as managed grasslands has been increasingly accelerated in recent years in China. Land use change affects soil nitrogen(N) dynamics and nitrous oxide(N_2O) emissions. However, it remains unclear how large-scale grassland reclamation will impact the grassland ecosystem as a whole. Here, we investigated the effects of the conversion from native to managed grasslands on soil N dynamics and N_2O emissions by field experiments in Hulunber in northern China. Soil(0–10 cm), nitrate(NO_3~-),ammonium(NH_4~+), and microbial N were measured in plots in a temperate steppe(Leymus chinensis grassland) and two managed grasslands(Medicago sativa and Bromus inermis grasslands) in 2011 and 2012. The results showed conversion of L. chinensis grassland to M.sativa or B. inermis grasslands decreased concentrations of NO_3~–-N, but did not change NH_4~–N . Soil microbial N was slightly decreased by the conversion of L. chinensis grassland to M.sativa, but increased by the conversion to B. inermis. The conversion of L. chinensis grassland to M. sativa(i.e., a legume grass) increased N_2O emissions by 26.2%, while the conversion to the B. inermis(i.e., a non-legume grass) reduced N_2O emissions by 33.1%. The conversion from native to managed grasslands caused large created variations in soil NO?3~-+–N and NH_4~–N concentrations. Net N mineralization rates did not change significantly in growing season or vegetation type, but to net nitrification rate. These results provide evidence on how reclamation may impact the grassland ecosystem in terms of N dynamics and N_2O emissions.     

节能环保产业公司融资效率研究——基于四阶段DEA-Malmquist模型

在经典的DEA模型的基础上进行了修正,采用四阶段DEA模型,旨在剔除环境控制变量对效率测度结果的影响.同时,在DEA模型的基础上引入Malmquist指数分析法,以弥补DEA模型无法测度面板数据的缺陷.选取了2012年-2014年A股节能环保上市公司的面板数据,测度了样本的融资效率及三年的融资效率变化情况,结果表明:资源循环利用行业的融资效率最高,其次是环保行业,融资效率最低的是节能行业.样本企业总体的融资效率每年都在增长,但增长速度开始放缓.     

高速铁路建设的环境影响分析及环保策略建议——以沪宁城际铁路为例

近年来高速铁路发展迅猛,与此同时高铁对沿线环境的影响及生态破坏已成为社会关注的热点问题,并引起国家及地方政府的高度重视.以沪宁城际高速铁路为研究案例,首先分析了高速铁路建设对沿线自然及生态环境影响的调查内容、方法和过程,然后论述了铁路噪声、振动电磁辐射、污水及固体废弃物对沿线环境的影响,并论述各类污染的生态防护措施.在此基础上,对沪宁城际铁路环保经验进行了总结归纳,最后提炼形成中国高速铁路建设发展的环保策略建议.     

中国化工园区雨排系统环境风险防控研究

雨排系统是化工园区重要的基础设施,如果没有建立有效的环境风险防控体系,污染物有可能通过园区雨排系统排入外环境,造成重大环境影响.目前,中国已出台的有关化工园区雨排系统环境风险防控的政策法规缺少强制性和统一性,监管标准缺失导致环保部门缺乏行之有效的监管手段,园区规划阶段协同机制的不健全也增加了后期监管的难度.鉴于目前中国化工园区雨排系统环境风险防控方面存在的问题,建议国家和地方加快监管标准出台,强化相关政策的落实,优化园区雨排系统,实施分类、分级管控,同时加强企业的监管.     

Toward a framework of environmental risk management for CO<Subscript>2</Subscript> geological storage in china: gaps and suggestions for future regulations

China encourages the demonstration of carbon capture and storage (CCS) projects. In an effort to identify gaps and provide suggestions for environmental risk management of carbon dioxide (CO₂) geological storage in China, this article presents a concise overview of potential health, safety and environmental (HSE) risks and environmental management regulations for CO₂ geological storage in Australia, Japan, the United States (USA), the European Union (EU), and the United Kingdom (UK). The environmental impact assessment (EIA) experience of Shenhua Ordos Coal-to-Liquid (CTL) Project and PetroChina Jilin Oil Field enhanced oil recovery (EOR) is subsequently analyzed in light of our field investigation, and gaps in current EIA guidelines that are applicable to CO₂ geological storage projects are identified. It is found that there are no specific environmental risk regulations suitable for CO₂ storage in China, and environmental risk management lags behind the development of CCS technology, which presents a challenge to demonstration enterprises in terms of assessing environmental risk. One major challenge is the overestimation or underestimation of this risk on the part of the enterprise, and another is a lack of applicable regulations for government sectors to supervise the risk throughout CCS projects. Therefore, there is a pressing need for China to formulate environmental management regulations that include environmental risk assessment, mandatory monitoring schemes, environmental emergency plans, and related issues.     

农药生产建设项目环境影响评价的探讨

分析了农药生产建设项目环境影响评价中存在的诸多问题。结合实际工作经验,就农药生产建设项目中的产业政策评价、环境影响的识别、环境风险评价、清洁生产评价和环保治理措施的确定进行了探讨。     

Removal of Cd2+ from water by Friedel's salt (FS:3CaO·Al2O3·CaCl2·10H2O): Sorption characteristics and mechanisms

The development of low-cost and efficient new mineral adsorbents has been a hot topic in recent years.In this study,Friedel's salt (FS:3CaO·Al2O3·CaCl2·10H2O),a hexagonal layered inorganic absorbent,wa...