Current methods of determination of chlorine in inorganic substances (Overview)

This is an overview of current methods of determination of chlorine in inorganic substances published in the last decade. Challenges of development of ICP-AES for determination of chlorine in aqueous media are demonstrated. Attention is paid to methods of determination not only of total chlorine and chloride ion, but to other forms of chlorine occurrence as well. Particular importance of determination of perchlorate ion is highlighted. Widely applied methods of ion chromatography, potentiometry, and spectrophotometry are presented in combination with flow analysis.     

Key issues in the targeted synthesis of inorganic substances

Chemistry is a science concerned with conversion of substances. From the chemical point of view, a substance is an assemblage of interacting particles, which is characterized by four properties: composition, structure, type of chemical bonding, and particle size. A conversion of a substance is a change in one or several of its properties. Targeted synthesis is a way of controlling a conversion of a substance. This paper considers thermodynamic and kinetic issues in targeted synthesis that are associated with control over the composition, structure, characteristic features of chemical bonding, and particle size and, hence, with the identification of conditions for the preparation of a substance with tailored properties. The concept of pure substance is discussed, which is an important issue for materials research and inorganic chemistry. It is pointed out that the composition of compounds should be characterized not only by their stoichiometry and impurity concentration but also by the related concentrations of native defects and impurities. In connection with this, a defect classification is presented and defect formation processes and techniques for controlling the defect composition are analyzed. Statistical criteria for assessing the compositional homogeneity of a pure substance are considered.     

离子色谱法测定电缆材料中氟含量的研究

无卤低烟阻燃电缆材料燃烧产生的酸性气体含量低,使用GB/T17650中的方法无法准确测量出氟离子的含量.通过氧气瓶燃烧的方式制备试样液,采用离子色谱法测定ST8型电缆护套料中氟含量.在选定的色谱条件下样品回收率在91.0％～97.5％之间,准确性高、抗干扰性强.     

Volume dependence of the bulk modulus of inorganic substances

An equation describing the change in the bulk modulus with the variation of the volume under high pressure or temperature is derived. It is shown that the derivatives ∂B/∂V for 56 metals and 120 ionic crystals MX (X = H, F, Cl, Br, I) vary from 4.2 to 5.4. Original Russian Text ? S. S. Batsanov, 2009, published in Neorganicheskie Materialy, 2009, Vol. 45, No. 4, pp. 509–512.     

茶叶中有机酸的测试方法概述

针对茶叶中有机酸测定前处理分析测试条件等不统一,导致测试结果无可比性的问题,该文在参阅1907年以来国内外关于茶叶中有机酸分析的30余篇文献的基础上,对茶叶中有机酸的分析方法做了较系统的归纳阐述,并对目前常用的分析方法包括高效液相色谱法、离子色谱法以及毛细管电泳色谱法等进行了评述,提出了茶叶中有机酸测定应进行标准化,以确保测试结果的可比性。     

Separation factors for the crystallization of inorganic substances from aqueous solutions

A method is proposed for evaluating separation factors for the crystallization of inorganic substances from aqueous solutions. The method allows the interaction between components of mixed electrolyte solutions to be assessed using basic data for binary solutions of the impurity and major component.     

Integrated system of databases on the properties of inorganic substances and materials

An integrated system of databases on the properties of inorganic substances and materials has been developed, currently combining the database of the A.A. Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, and an AtomWork database on the properties of inorganic substances, developed at the National Institute for Materials Science (Japan). This system is developed as an information service for specialists and for computer-aided design of new inorganic compounds, which was supported by an elaborate information-analytical system. The results of application of this system for compound design that have not yet been synthesized are presented.     

离子色谱法测定生活水体中氟氯离子方法的研究

基于离子色谱方法原理测定水体中氟氯离子的含量.本文主要对离子色谱仪的方法条件进行优化,获得最佳的测量条件,并对方法的线性、检出限、重复性、及回收率进行分析实验.曲线相关系数大于0.999,回收率范围氟离子:96％-106％;氯离子:95％-104％;相对标准偏差(RSD)≤2.8％;方法定量下限氟离子:0.012mg/...     

水产品中氟化物的离子色谱法

本文提出用离子色谱检测水产品中的氟化物。样品经过600℃灰化,酸性下蒸馏后,用碱液吸收上机。采用阴离子柱分离,电导检测。流动相为Na2CO3/NaHCO3=6mM/1mM。50μL进样,检测限可达0.05mg/kg。线形范围为,0.05~5×103mg/kg。方法的回收率为86~93%。方法有选择性好,灵敏度高的优点。     

氟树脂对聚偏氟乙烯膜疏水性的影响

采用N,N-二甲基甲酰胺(DMF)为溶剂,以氟树脂为疏水助剂,制备聚偏氟乙烯(PVDF)膜.采用不同偶联剂对疏水助剂氟树脂进行改性,研究了改性氟树脂对PVDF膜疏水性的影响.研究结果表明:添加疏水助剂氟树脂可改善PVDF膜的疏水性.当经偶联刺G502改性的氟树脂添加量为10%时,PVDF膜与水的静态接触角达到120°.通过集灰实验表明添加改性氟树脂的PVDF膜具有较好的疏水性.     

Removal of arsenic and humic substances (HSs) by electro-ultrafiltration (EUF)

A laboratory scale electro-ultrafiltration (EUF) system was developed and used to explore the removal of arsenic and humic substances (HSs) from water. As a negatively charged species, arsenate(V) was readily removed after applying voltage to the EUF cell. Arsenite(III) was removed via EUF after the pH of the water had been adjusted. Meanwhile, the rejection of HSs increased due to the presence of an electric field. This study also showed that the removal of arsenite(III) from water relies primarily on electrostatic and non-electrostatic mechanisms. In the presence of HSs, arsenate(V) complexed with the HSs and was then able to be removed by EUF. This study demonstrates that EUF is a highly promising means of removing arsenic from water.     

Bond performance of reinforcing bars in inorganic polymer concrete (IPC)

The basic mechanical and chemical properties of fly-ash-based inorganic polymer concretes (IPC) have been studied widely, but, key engineering and structural properties of the material for instance modulus of elasticity, compressive, tensile, flexural strengths and bonding strength of the material to reinforcement have received little attention. Structural applications of reinforced IPC depend on the bond performance of the material to the reinforcement. Due to their difference with ordinary Portland cement (OPC) based concrete in terms of chemical reaction and matrix formation it is not known whether IPC exhibit different bonding performance with the reinforcement. Simply relying on compressive strength of the material and extrapolating models and equations meant for OPC based concrete may lead to unsafe design of structural members. To that end, 27 beam-end specimens, 58 cubic direct pullout type specimens and number of laboratory test specimens were tested to evaluate bonding performance of IPC with reinforcement. The results of beam-end specimens and direct pullout type specimens correlate favourably, although the results of direct pullout tests are in general more conservative than those of beam-end specimens. Overall, it can be concluded that bond performance of IPC mixes are comparable to OPC based concrete and therefore IPC and steel can be used as a composite material to resist tension in addition to compression.     

Influence of inorganic soil components and humic substances on the mechanochemical removal of pentachlorophenol

The influence of the presence of humic acids of different origin on the catalytic transformation of pentachlorophenol (PCP) by two metal oxides, ferrihydrite and birnessite, using mechanochemical contact was studied. The mechanochemical dry contact with light grinding of PCP and birnessite was more effective than that observed in the presence of ferrihydrite (approximately 70 and 40% of PCP removal after 20 days, respectively). The removal of PCP by birnessite and ferrihydrite was significantly enhanced in the presence of humic acid (HA). The different origin of humic acids (agricultural, forest and commercial) showed a slight influence on the overall reaction. The commercial HA, when mixed with birnessite, was more effective in reducing PCP concentration compared to the others two HAs investigated. The transformation process in the presence of birnessite with and without HA was accompanied by the release of four chlorides per molecule of PCP transformed.     

1999～2001年日本气体设备市场综述

综述了1999－2001年日本气体设备市场状况。     

Effect of humic substances on Cu(II) solubility in kaolin-sand soil

The type and amount of organic matter present in industrially contaminated soils will influence the risk they pose. Previous studies have shown the importance of humic and fulvic acids (FAs) (important components of soil organic matter) in increasing the solubility of toxic metals but were not carried out using toxic metal levels and the pH range typical of industrially contaminated soils. This study investigated the influence of three humic substances (HSs: humates, fulvates and humins) on the solubility of copper(II) ions in kaolinitic soil spiked with Cu at levels representative of industrially contaminated soil. Humates, fulvates and humin were extracted from Irish moss peat, and controlled pH batch leaching tests were conducted on an artificial kaolin-sand soil that was spiked with each. Further leaching tests were conducted on soil spiked with each HS and copper nitrate. Dissolved organic contents were determined by titration and total and free aqueous copper concentrations in the leachate were measured using AAS and ion selective electrode (ISE) potentiometry respectively (dissolved complexed copper levels were determined by difference). It was found that humates and fulvates are partially sorbed by the soil, probably by chemisorption on positively charged gibbsite (Al-hydroxide) sites in the kaolinite. The addition of 340 mg/kg Cu(II) ions did not significantly affect the amount of humate or fulvate sorbed. Dissolved humates and fulvates form soluble complexes with copper over the pH range 3-11. However, in the presence of kaolinite, soluble copper humates and fulvates are unable to compete with the kaolinite for Cu ions at pH 6-7. Above pH 8, humate and fulvate complexes are the only forms of dissolved Cu. Humin is largely insoluble and has little effect on Cu mobility between pH 2 and 12. The implication of this study is that measurement of total soil organic content and water leaching tests should be a standard part of contaminated site investigation.