Online electro-Fenton-mass spectrometry reveals 2,4′,5-trichlorobiphenyl oxidation products and binding to organic matter

Electrochemistry–mass spectrometry is used to simulate redox reactions in many research disciplines because this technique is fast and provides information on compound metabolites. However, the analysis of the degradation of refractory organic pollutants by reactive oxygen species is difficult to achieve by the electrochemistry step. Therefore, here we use online electro-Fenton-mass spectrometry to study for the first time the oxidation of 2,4′,5-trichlorobiphenyl [polychlorinated biphenyl (PCB) 31] by reactive oxygen species and the binding reactions of PCB degradation products with model substances of natural organic matter. The degradation products were identified by coupled Q Trap mass spectrometry. We observed a binding of a degradation product with γ-l-glutamyl-l-cysteinyl-glycine. We propose a transformation pathway. We conclude that online electro-Fenton-mass spectrometry is a promising technique to study the oxidation of refractory organic pollutants and further binding of degradation products with natural organic matter.     

聚乳酸解聚方法研究进展

综述了近年来国内外关于聚乳酸的热解聚法和酸性水解法、碱性水解法、中性水解法、高温高压水解法、酶催化法、甲醇醇解法、正丁醇醇解法等化学解聚法的研究进展,并对聚乳酸在离子液体环境中进行化学解聚的可行性进行了探讨和展望。     

石灰石煅烧煤矸石水泥处理镍污染土的固化特性北大核心CSCD

随着碳排放量的增加,使用可持续且有效的低碳低成本胶结材料在污染土壤的稳定/固化方面受到了广泛关注。本研究通过无侧限抗压强度、毒性浸出、X射线衍射、扫描电镜等试验来确定新型低碳低成本石灰石煅烧煤矸石水泥对重金属镍污染土的固化特性。结果表明:强度随着养护龄期的增长而增加,随着镍离子浓度的增加而降低;镍离子浸出浓度随着养护龄期的增长而降低,随着镍离子浓度的增加而增大;pH较大(碱性环境),有利于促进水泥对重金属污染土壤的固化效率;X射线衍射和扫描电镜试验表明,生成水化硅酸盐、钙矾石等水化产物及不溶性金属氢氧化物是稳定镍的主要方式。石灰石煅烧煤矸石水泥可以为重金属镍污染土提供环保且可持续的固化修复,处理后的固化土可作为建筑材料循环使用。     

废水中糠醛的比色测定

本文采用醋酸苯胺与糠醛作用缩合成红色化合物的特性,运用正交设计合理选择实验条件.取经水蒸汽蒸馏后的炼油废水样品,加入醮酸苯胺和稳定剂,在20℃的水浴中显示40分钟,于波长518nm处比色测定糠醛含量.测定上限3.0mg/L,最低检出浓度为0.3mg/L,加标回收率90—110％,变异系数<5％。     

环境风险规制的经济成本及次生影响——决策中需要重视的向度

环境风险是社会经济发展的副产物,是市场外部性的表现,需要公共部门的参与解决.然而环境风险的应对并非没有代价,这种代价既包括规制的经济成本,也包括其带来的次生影响.我国经济发展到目前的阶段,政府和公众都非常关注环境风险,并出台了大量的规制性政策对其进行治理.如何在实现环境治理目标的同时,合理控制经济成本、尽量减少次生影响是提升环境治理效能的重要命题,本文针对这一问题进行了探讨.主要对规制的经济成本和次生影响等关键概念做了辨析,对规制的经济成本和次生影响在我国被忽略的可能原因进行了分析,对他国应对这一问题所采取的措施开展了讨论.最后提出在我国针对重大环境规制性政策开展规制影响评估的建议.     

基于Crowbar保护电路的双馈风电系统高电压穿越

针对电网电压发生骤升故障时造成的电网不稳定运行,在双馈机组转子侧加入Crowbar保护电路,增加双馈风电系统高电压穿越的能力。通过建立电网电压骤升时双馈风电机组投入Crowbar保护电路后的数学模型,并从磁链角度推导出转子侧暂态电流及其最大估算值,根据短路电流和直流侧母线耐受电压的大小,确定Crowbar电路串联的电阻值、切入和退出时间,加速系统暂态电流的衰减,实现双馈系统的高电压穿越。Matlab/Simulink仿真结果表明:控制方案增强了双馈发电系统稳定运行的可靠性,并提高了双馈风力发电系统的高电压穿越能力。     

Prediction of primary energy demand in China based on AGAEDE optimal model

In this article,we present an application of Adaptive Genetic Algorithm Energy Demand Estimation(AGAEDE) optimal model to improve the efficiency of energy demand prediction.The coefficients of the two forms of the model(both linear and quadratic) are optimized by AGA using factors,such as GDP,population,urbanization rate,and RD inputs together with energy consumption structure,that affect demand.Since the spurious regression phenomenon occurs for a wide range of time series analysis in econometrics,we also discuss this problem for the current artificial intelligence model.The simulation results show that the proposed model is more accurate and reliable compared with other existing methods and the China's energy demand will be 5.23 billion TCE in 2020 according to the average results of the AGAEDE optimal model.Further discussion illustrates that there will be great pressure for China to fulfill the planned goal of controlling energy demand set in the National Energy Demand Project(2014—2020).     

Effects of investment on energy intensity: evidence from China

This article explores the effects of investment upon energy intensity by applying a unique panel data of China’s 27 provinces between 2004 and 2013. In addition, it also particularly studies other factors, such as energy price, economic structure, and urbanization. The results, based on four econometric regression model results, suggest that in general, the indigenous investment on research and development is a more powerful tool to decrease China’s energy intensity regardless of region disparity. The foreign direct investment (FDI) has a prominent but not persistent effect on energy intensity. However, the outward direct investment has not shown its significant impact on energy intensity. At the level of an aggregate economy and China’s eastern region, the results demonstrate that FDI improves energy efficiency significantly. For the central and western provinces, FDI does not support the similar conclusion. Based on these analyses, we present the corresponding regional policies for policymakers.     

复合生物滤池处理城市高污染水体

采用中试规模复合生物滤池处理城市高污染水体,考察了滤池的最佳运行参数以及对氮和有机物的去除效果。结果表明:滤池容积负荷宜控制为0.3～0.5 kg COD/(m3.d),水力负荷4.5～5 m3/(m2.d),适宜的通风比为9%,当C/N为5～8时,滤池COD、NH4+-N和TN平均去除率分别为80%、83%和63%,达到高效同步硝化反硝化状态。     

氮素形态与光强对苗期黄瓜吸收累积菲的影响研究

采用营养液培养的方法研究了不同形态氮素(NH4 -N、NO3 -N)和光强对菲胁迫条件下黄瓜幼苗生长及光合特性的影响.结果表明:①与供NO3- -N营养相比,供NH4 -N营养可同时增强黄瓜幼苗的抗菲胁迫及耐弱光的能力;②以NH4 -N为营养的黄瓜吸收的菲不仅运输至叶片的比例相对较低,而且运输至新生叶片的比例也相对较少,相对降低了新生叶中的菲累积,因而使得以NH4 -N为营养的黄瓜新生叶片维持了相对较大的光合面积和较高的光合速率.由此可见,与NO3- -N营养相比,NH4 -N营养能改善黄瓜在菲胁迫环境中的生长状况,尤其在弱光条件下,这种现象更加明显.