环境中全氟有机物的毒性、检测分析及降解

自全氟有机物广泛使用50多年以来,已经在世界范围内发现一定浓度的全氟有机物,各国研究人员针对该类物质特别是全氟辛酸(PFOA)、全氟辛烷基磺酸(PFOS)进行了一定的研究.介绍了该类物质的污染现状,阐述了全氟有机物的毒性、检测分析技术及降解技术,在此基础上提出了今后的研究方向.     

高能等离子体分解CO_2气体研究

为治理温室气体ＣＯ_２，本工作在低温常压条件下，利用超高压脉冲电晕放电产生的高能量（２０～５０ｅＶ）非平衡等离子体作用于ＣＯ_２气体分子，使ＣＯ_２分子化学结合键断裂，在定向化学反应作用下，将ＣＯ_２气体分解成单原子气体分子Ｏ_２和单质固体微粒Ｃ。ＣＯ_２分解率在９０％以上。     

Application of human factors evaluation in engineering design and safe operation of dense phase ethylene treaters

Ethylene treaters are widely used in the petrochemical industry to remove impurities from ethylene feedstock imported from pipeline networks or storage caverns. The safety concerns of dense phase ethylene treaters due to the reactive and highly flammable nature of ethylene are well known and studied. Under certain conditions, ethylene may self-polymerize and decompose violently with heat release. Under other conditions, ethylene will auto-refrigerate, generating cold liquids that may cause potential brittle fracture hazards. Therefore, dense phase ethylene treaters present design challenges with the unique combination of high temperature decomposition and cold temperature brittle fracture hazards.Due to these safety concerns, it is important to select the appropriate engineering design options for dense phase ethylene treaters and the associated regeneration facilities. Totally automated treater regeneration systems add complexity and instrument maintenance requirements while manually operated systems rely heavily on operator training and procedures. Unfortunately, little or no information or design guidance is available from published research findings in the literature on the evaluation and risk assessment of current industrial design options and practices for dense phase ethylene treaters.This paper presents a systematic risk assessment method to evaluate the engineering design and safe operation options for dense phase ethylene treaters. The proposed risk assessment method integrates human factors task analysis into the traditional HAZOP, LOPA and fault tree analysis to allow evaluation of automated, manual and hybrid approaches with a goal of selecting and optimizing design options to ensure plant safety. This approach provides a realistic assessment of the operational risk and allows identification of fit-for-purpose risk reduction. Applying this systematic risk assessment approach, a simpler and more cost effective design solution can be justified, thereby avoiding the need for a high integrity protective system.     

Determinants of CO2 emissions in Brazil and Russia between 1992 and 2011: A decomposition analysis

This paper deals with the decomposition analysis of energy-related CO₂ emissions in Brazil and Russia from 1992 to 2011. The refined Laspeyres index (RLI) method applied and both aggregated and sectoral changes in CO₂ emissions decomposed. Brazil’s and Russia’s economies divided into three economic sectors including agriculture, industry and services. Impact of four main factors, such as economic activity, employment, energy intensity, and carbon intensity in CO₂ emissions changes were analyzed. The aggregated decomposition analysis revealed that Brazil is still far from a decoupling between economic growth and carbon dioxide emissions where Russia achieved a substantial decline in carbon emissions mainly due to the improved energy intensity. The empirical findings of sectoral decomposition analysis emphasized that the economic activity was the major CO₂ increasing factor in Brazil’s economic sectors. On the other hand the economic activity effect followed a reducing impact in Russia’s sectoral emissions until 2000. The structural changes between sectors and their impacts on CO₂ emissions were captured by employment effect. Energy intensity and carbon intensity effects underlined that environmental sustainability widely neglected in Brazil and Russia during the study period. The results yield important hints for energy planning and sustainable environment.     

Decomposition of Al13 promoted by salicylic acid under acidic condition: Mechanism study by differential mass spectrometry method and DFT calculation

Decomposition of the polycation Al₁₃O₄(OH)₂₄(H₂O)₁₂⁷⁺ (Al₁₃) promoted by ligand is a vital subject to advance our understanding of natural and artificial occurrence and evolution of aluminum ions, especially in the case of acidic condition that dissolved Al³⁺ species can be released from the Al-bearing substances. However, the microscopic pathway of synchronous proton-promoted and ligand-promoted decomposition process for Al₁₃ is still in the status of ambiguity. Herein, we applied differential mass spectrometry method and DFT calculation to study the initial detailed process of Al₁₃ decomposition under the presence of proton and salicylic acid (H₂Sal). Mass results showed that the mononuclear Al³⁺-H₂Sal complexes dominated the resulting Al species, whereas the monodentate complex Al₁₃HSal⁶⁺ was not observed in the spectra. The difference of decomposition levels between the ligand/Al ratio 0.2 and 0.5 cases revealed that proton and ligand performed synergistic effect in initial Al₁₃ decomposition process, and the proton transfer determined the ring closure efficiency. The ring closure reaction is the prerequisite for the collapse of Al₁₃ structure and detachment of the mononuclear complex. DFT calculations reveal that hydrogen bond plays an important role in inducing the formation of chelated complex accompanying proton transfer. Attachment of protons at the bridging OH⁻ can elongate and weaken the critical bond between targeted Al³⁺ and µ₄-O^2- resulting from delocalization of electron pairs in the oxygen atom. These results demonstrate the detailed mechanism of Al₁₃ composition promoted by ligand and proton, and provide significant understanding for further application and control of Al₁₃.     

无锡市碳排放的因素分解模型及实证分析

在计算无锡市2000~2011年二氧化碳排放量的基础上,采用对数平均权重Divisia分解法,建立无锡市人均碳排放的因素分解模型,定量分析能源结构、能源效率、经济发展情况等因素对无锡市人均碳排放的影响。结果显示经济发展对拉动无锡人均碳排放的贡献率呈指数增长趋势,相比之下,能源效率及能源结构对碳排放的抑制作用并不明显。据此提出开发可再生能源,转变能源消费结构,发展清洁煤技术,提高能源利用率等对策。     

光合细菌两段流化床处理鸡粪粪水的研究

光合细菌对高浓度有机废水具有较好的适应性和处理能力,特别是作为一个预处理工艺对后续污水处理可以产生重要的影响。鉴于光合细菌生长时间相对较长,为提高光合细菌对高浓度有机污水的处理效率,本研究利用光合细菌两段流化床反应器对鸡粪粪水进行降解。试验结果表明:经过60 d的启动运行后,反应器进入稳定状态,在进水pH值6.0,COD小于10000mg/L范围内,流化床水力停留时间(HRT)为48 h时,对废水COD去除率为88.10%,TN去除率为68.29%,NH3-N去除率为94.42%,NO3-N去除率为65.43%。     

Fine root decomposition and nutrient release in Toona sinensis plantation under the reconstruction mode of low-efficiency cypress forest gaps北大核心CSCD

Fine root decomposition is an important way in which nutrients are returned to plantation soil; thus, further study of this process will be helpful for understanding material cycling in forest ecosystems. We investigated a Toona sinensis plantation in the central Sichuan hilly region using litter bags containing T. sinensis fine roots to evaluate the dynamics of fine root decomposition and nutrient release for one year in forest gaps of 50 m2 (L1), 100 m2 (L2), and 150 m2 (L3). The results showed that T. sinensis fine root decomposition was fastest in the first 90 days. As time passed, the decomposition rate slowed. One year later, the residue rate was 75.44%, 73.92%, and 72.07%, respectively. The fine root decomposition rate of L3 was greater than that of L2, which was greater than that of L1. During fine root decomposition, the dynamics of the fine root nutrient concentrations changed. C, P, and K concentrations of the fine roots declined in forest gaps, while N, Ca, and Mg concentrations increased overall in the fine roots. In conclusion, forest gaps had effects on the fine root decomposition and nutrient release of T. sinensis, and different sized forest gaps produced different results. © 2018 Science Press. All rights reserved.     

Decomposition and oxidation of sodium 3,5,6-trichloropyridin-2-ol in sub- and supercritical water

Sodium 3,5,6-trichloropyridin-2-ol (STCP) is a necessary precursor compound for the production of chlorpyrifos and triclopyr, which are extensively used as pesticide and herbicide, respectively. In the process of STCP production, however, large amount of wastewater containing STCP is discharged, which causes increasingly environmental concerns. Therefore, it is of great significance to develop a rapid and effective method for the disposal of containing STCP contaminants. In this work, the thermal decomposition of STCP in sub- and supercritical water was investigated using a continuous tubular reactor. While STCP was stable below 280 °C, it could be effectively decomposed at elevated temperature. FT-IR spectra of the decomposition products indicated that the pyridine ring structure in the STCP molecule was stable even at temperatures up to 400 °C. The decomposition reaction was mainly caused by the substitution of Cl groups in the STCP molecule with OH groups, resulting in polyhydroxylated pyridines as the major decomposition product. Moreover, high pressure favored the substitution reaction. To completely decompose STCP into non-toxic or low toxic compounds, supercritical water oxidation (SCWO) was employed to evaluate the oxidation of STCP using H₂O₂ as an oxidant. It was found that STCP could be completely oxidized to H₂O, CO₂ and corresponding inorganic ammonium salts with an oxidation rate of 99%.     

水中臭氧分解动力学研究

在磷酸盐缓冲液中研究了臭氧的自分解,根据臭氧分解机理推导出其动力学方程。由不同温度和pH值下的实验结果确定出kT,0,n以及活化能E。