聚苯乙烯热降解动力学参数与降解反应机理关系

基于Arrhenius理论及相关公式,推导出表观活化能与幂指数相对变化关系。这种相对变化关系与聚苯乙烯热降解、热氧化降解、及其在各种添加剂情形下热降解动力学参数变化特征完全吻合。     

制药行业废炭的再生与利用

采用强制放电技术，通过对东北制药总厂部分车间的废炭进行吸附能力恢复试验，找出一种废炭再生方法．此工艺简单、易于操作，所需人员少，吸附能力恢复率４００％以上，每千克炭能耗２．５ｋＷ／ｈ，再生温度８５０℃．     

面向固体热解单一活化能计算的等转化率动力学分析方法研究

基于改进的Vyazovkin方法,提出了一种新的求解固态反应活化能的等转化率方法。这种方法不仅避开了对反应机理的选择,而且突破了当前等转化率方法不能像拟合法一样求解出明确的活化能的局限。通过对模拟数据及挤塑聚苯乙烯热解实验数据的验证,证实了这种方法对实验噪音具有良好的容许度,并且能够对热重数据的一阶导数据有明显的多峰多歩反应求解出比拟合法更可信的活化能的值。     

Weak magnetic field accelerates chromate removal by zero-valent iron

Weak magnetic field(WMF) was employed to improve the removal of Cr(VI) by zero-valent iron(ZVI) for the first time. The removal rate of Cr(VI) was elevated by a factor of 1.12–5.89 due to the application of a WMF, and the WMF-induced improvement was more remarkable at higher Cr(VI) concentration and higher p H. Fe2+was not detected until Cr(VI) was exhausted, and there was a positive correlation between the WMF-induced promotion factor of Cr(VI) removal rate and that of Fe2+release rate in the absence of Cr(VI) at pH 4.0–5.5. These phenomena imply that ZVI corrosion with Fe2+release was the limiting step in the process of Cr(VI) removal. The superimposed WMF had negligible influence on the apparent activation energy of Cr(VI) removal by ZVI, indicating that WMF accelerated Cr(VI)removal by ZVI but did not change the mechanism. The passive layer formed with WMF was much more porous than without WMF, thereby facilitating mass transport. Therefore,WMF could accelerate ZVI corrosion and alleviate the detrimental effects of the passive layer, resulting in more rapid removal of Cr(VI) by ZVI. Exploiting the magnetic memory of ZVI, a two-stage process consisting of a small reactor with WMF for ZVI magnetization and a large reactor for removing contaminants by magnetized ZVI can be employed as a new method of ZVI-mediated remediation.     

Concentration of radionuclides in hydrosphere affected by Temelín Nuclear Power Plant in Czech Republic

The paper presents results of a long-term field study of the possible impact of Temelín NPP on the Vltava and Elbe Rivers. The study was divided into 2 stages: before and after the operation of the NPP. The main goal of the investigation before the operation (1989–2000) was to determine the background levels of radionuclides resulting from the tests of nuclear weapons and the Chernobyl accident for different components of the environment. The paper discusses also the risk of a river radioactive contamination due to the tritium discharges in wastewater from Temelín NPP. During the operation period of 2001–2006, the results of the monitoring did not detect any impact of Temelín NPP on the concentrations of activation and fission products in the hydrosphere, apart from tritium. The annual average tritium concentrations in the Vltava River correspond with the previously calculated predictions for the conditions of the average and minimum guaranteed flows. The maximum concentration of tritium of 26.6 Bq/l in Vltava River at Prague was observed after dry period in 2003.     

ZR-BV阻燃电缆绝缘材料热老化寿命研究

利用热分析技术,在实验的基础上对阻燃绝缘材料热老化寿命进行了研究．推算出了电缆热老化寿命快速评定法的计算公式,对不同载流情况下电缆绝缘材料热老化寿命进行了比较,并对电缆热老化程度进行了分析。     

Diffusion mechanism of chloride ions in sodium montmorillonite

For safety assessment of geological disposal of HLW, it is necessary to understand the diffusion mechanism of radionuclides in compacted bentonite. In this study, the diffusion behavior of chloride ions in compacted montmorillonite was studied from the viewpoints of the activation energy for apparent diffusion and the basal spacing of the compacted montmorillonite. A unique change in the activation energy as a function of the dry density of the montmorillonite was found. The activation energy decreased from 17.4 to 13.5 kJ mol-1 as the dry density increased from 0.7 to 1.0 Mg m-3 and increased to 25.1 kJ mol-1 at dry densities above 1.0 Mg m-3. The basal spacing of 1.88 nm, corresponding to the three-water layer hydrate state, was not observed by X-ray diffraction (XRD) until the dry density increased to 1.0 Mg m-3, where the minimum activation energy was obtained. On the other hand, a basal spacing of 1.56 nm, corresponding to the two-water layer hydrate state, was observed at the dry densities of 1.4 Mg m-3 and above, where the activation energies were more than 22 kJ mol-1. These experimental results suggest that there are at least two additional diffusion processes that can raise or reduce the activation energy and are affected by water in the region adjacent to the montmorillonite surfaces. If the "Grahame model" can be introduced to describe the electrical double layer, surface diffusion will be considered the possible predominant diffusion process, even for anions like chloride ions.     

Relationship between electric spark sensitivity and activation energy of the thermal decomposition of nitramines for safety measures in industrial processes

This study presents a new simple correlation between electric spark sensitivity of nitramines and their activation energies of thermolysis, which are important for safety measures in industrial processes. The new correlation can help to elucidate the mechanism of initiation of energetic materials by electric spark. It can be used to predict the magnitude of electric spark sensitivity of new nitramines, which is difficult to measure. The methodology assumes that electric spark sensitivity of a nitramine with general formula C_aH_bN_cO_d can be expressed as a function of its activation energy of thermal decomposition as well as optimized elemental composition and the contribution of specific molecular structural parameters. The new correlation has the root mean square and the average deviations of 1.37 and 1.09 J, respectively, for 21 nitramines with different molecular structures. The proposed new method is also tested for 16 nitramines so that there is no experimental data of electrostatic sensitivity for them.     

福建茶园土壤Zn含量及其影响因素

通过对62份福建茶园土壤样品的测定,应用通径分析等统计方法研究了土壤Zn含量及其有效性等的影响因素。结果表明：福建茶园土壤全Zn质量分数平均值为28.85 mg.kg-1,中值58.80 mg.kg-1,变异系数45.16%;有效Zn质量分数为0.11~15.04 mg.kg-1,平均值为2.95 mg.kg-1,中值1.47 mg.kg-1,变异系数123.14%;Zn活化率0.26%~24.53%,平均值为5.02%,中值2.72%,变异系数114.87%。相关分析表明全Zn与pH呈极显著正相关,有效Zn与有机质、全氮呈极显著正相关;Zn活化率与pH呈极显著负相关,与有机质、全N呈极显著正相关。通径分析表明pH对全Zn的直接效应最明显;全N对有效Zn和Zn活化率的直接效应最明显,pH和全P对有效Zn和Zn活化率也有较大的负效应。     

Application of percarbonate and peroxymonocarbonate in decontamination technologies

Sodium percarbonate (SPC) and peroxymonocarbonate (PMC) have been widely used in modified Fenton reactions because of their multiple superior features, such as a wide pH range and environmental friendliness. This broad review is intended to provide the fundamental information, status and progress of SPC and PMC based decontamination technologies according to the peer-reviewed papers in the last two decades. Both SPC and PMC can directly decompose various pollutants. The degradation efficiency will be enhanced and the target contaminants will be expanded after the activation of SPC and PMC. The most commonly used catalysts for SPC activation are iron compounds while cobalt compositions are applied to activate PMC in homogenous and heterogeneous catalytical systems. The generation and participation of hydroxyl, superoxide and/or carbonate radicals are involved in the activated SPC and PMC system. The reductive radicals, such as carbon dioxide and hydroxyethyl radicals, can be generated when formic acid or methanol is added in the Fe(II)/SPC system, which can reduce target contaminants. SPC can also be activated by energy, tetraacetylethylenediamine, ozone and buffered alkaline to generate different reactive radicals for pollutant decomposition. The SPC and activated SPC have been assessed for application in-situ chemical oxidation and sludge dewatering treatment. The challenges and prospects of SPC and PMC based decontamination technologies are also addressed in the last section.