Development of an accurate,sensitive, and robust isotope dilution laser ablation ICP-MS method for simultaneous multi-element analysis (chlorine,sulfur, and heavy metals) in coal samples

A method for the direct multi-element determination of Cl, S, Hg, Pb, Cd, U, Br, Cr, Cu, Fe, and Zn in powdered coal samples has been developed by applying inductively coupled plasma isotope dilution mass spectrometry (ICP-IDMS) with laser-assisted introduction into the plasma. A sector-field ICP-MS with a mass resolution of 4,000 and a high-ablation rate laser ablation system provided significantly better sensitivity, detection limits, and accuracy compared to a conventional laser ablation system coupled with a quadrupole ICP-MS. The sensitivity ranges from about 590 cps for ³⁵Cl⁺ to more than 6 × 10⁵ cps for ²³⁸U⁺ for 1 μg of trace element per gram of coal sample. Detection limits vary from 450 ng g⁻¹ for chlorine and 18 ng g⁻¹ for sulfur to 9.5 pg g⁻¹ for mercury and 0.3 pg g⁻¹ for uranium. Analyses of minor and trace elements in four certified reference materials (BCR-180 Gas Coal, BCR-331 Steam Coal, SRM 1632c Trace Elements in Coal, SRM 1635 Trace Elements in Coal) yielded good agreement of usually not more than 5% deviation from the certified values and precisions of less than 10% relative standard deviation for most elements. Higher relative standard deviations were found for particular elements such as Hg and Cd caused by inhomogeneities due to associations of these elements within micro-inclusions in coal which was demonstrated for Hg in SRM 1635, SRM 1632c, and another standard reference material (SRM 2682b, Sulfur and Mercury in Coal). The developed LA-ICP-IDMS method with its simple sample pretreatment opens the possibility for accurate, fast, and highly sensitive determinations of environmentally critical contaminants in coal as well as of trace impurities in similar sample materials like graphite powder and activated charcoal on a routine basis. Figure LA-ICP-IDMS allows direct multi-element determination in powdered coal samples     

Progressive Vocal Cord Dysfunction Subsequent to a Chlorine Gas Exposure

Chlorine gas inhalation, similar to other toxic gas exposures, can impart a variety of effects to the entire airway ranging from mucous membrane irritation to acute respiratory distress syndrome. The extent and location of damage is determined by numerous situational factors such as the duration of exposure, quantity of gas released, environmental factors, and instituted chemical defense measures. Reactive airways dysfunction and nonspecific bronchial hyperresponsiveness are commonly reported as sequelae to chlorine exposure. This article constitutes the first case of a single antecedent chlorine exposure inducing progressive vocal cord dysfunction.     

淋洗液自动发生-离子色谱法测定重整催化剂中氯的含量

建立了重整催化剂中氯含量的淋洗液自动发生-离子色谱测定方法.以4 mL 7.5 mol/L NaOH溶液提取重整催化剂中Cl-,以淋洗液自动发生装置产生的KOH溶液为流动相,进行离子色谱法测定.结果表明,溶液中Cl-线性关系良好,相关系数为0.9999,测定结果的RSD小于0.76%,加标回收率为98.7%～102.8...     

常见氯盐溶液水的拉曼包络线高斯-洛仑兹去卷积分峰定量研究

为了探索地质流体中常见阳离子的拉曼光谱定量方法, 在室温下对NaCl-H₂O, CaCl₂-H₂O, MgCl₂-H₂O, CuCl₂-H₂O, ZnCl₂-H₂O和FeCl₃-H₂O体系3 000～3 800 cm-1范围水的O—H伸缩振动区域进行了高斯-洛仑兹去卷积分峰,并对所得积分参数进行了分析。结果显示：(1)不同体系拟合后参数比(峰强比、半高宽比和积分面积比)与浓度的线性相关程度不尽相同,但对于所有体系来说拟合峰强度比(低频/高频)与浓度的线性关系均很好,完全符合定量要求,为室温下定量分析这些体系盐溶液,提供了一种便捷、可靠的定量方法。(2)拟合峰的强度比(低频/高频)随浓度的变化,在NaCl-H₂O,CaCl₂-H₂O和MgCl₂-H₂O体系中,随浓度增加,强度比呈下降趋势,说明分子间氢键逐渐减少;然而在CuCl₂-H₂O,ZnCl₂-H₂O和FeCl₃-H₂O体系却是呈上升趋势,说明分子间氢键逐渐增多,可能与这三个体系均是过渡金属离子氯盐在水中形成络合物作用有关,尚需进一步研究。(3)通过各个体系强度比与浓度关系一次拟合曲线斜率可以看出对水分子氢键的影响能力CaCl₂和MgCl₂＞NaCl;FeCl₃＞ZnCl₂和CuCl₂。     

水样中低含量氯的分离与同位素质谱法测定

采用阳离子交换树脂,动态和静态交换相结合,对低氯浓度样品特别是雨水中的氯进行分离、提纯的简易方法。氯的回收率大于97％,能满足氯同位素质谱测定需要。氯同位素采用基于Cs2Cl^ 离子的正热电离质谱法测定,结果表明分离过程无明显的同位素分馏,本方法为雨水的氯同位素地球化学研究提供了可能。     

微孔晶体材料C12A7-Cl-的表面氯负离子发射性能和机理

利用飞行时间质谱(TOF-MS)观测到氯负离子从合成的微孔晶体材料C12A7-Cl-(11CaO·7Al2O3·CaCl2)表面发射出来, 详细研究了C12A7-Cl-的发射特性, 包括发射强度分支比、温度效应、电场效应和表观活化能. 在我们的检测范围内从C12A7-Cl-表面发射的离子中绝大部分是氯负离子(最大强度分支比为98%), 此外还有弱的氧负离子和电子发射. 各种离子的绝对发射电流强度都随着表面温度升高或引出电场强度的增加而显著增强, 随着引出电场强度从200增加到1200 V·cm-1, 氯负离子发射的表观活化能从180.9 kJ·mol-1减小到110.0 kJ·mol-1. 氯负离子和C12A7-Cl-表面之间的结合能大约是228 kJ·mol-1. 研究了氯负离子的发射稳定性, 并且应用一种电化学注入法, 以获得持续的氯负离子发射. 基于上述实验还讨论了氯负离子的形成和发射机理. 目前的方法可望被用于发展氯负离子储存/发生器.     

Reactions of 1,1′‐Diphosphaferrocene with CuCl and CuBr Resulting in Cu4P4X4Fe2 (X = Cl,Br) Complexes with Adamantane‐like Topologies

Cu₄P₄X₄Fe₂ (X = Cl, Br) cages are formed upon reactions of octaethyl‐1,1′‐diphosphaferrocene (odpf) with the respective Cu^I halide in CH₂Cl₂/CH₃CN solvent mixtures. These cages have adamantoid Cu₄X₄P₂ cores with two planar anelated CuP₂Fe rings as the flaps. Both complexes 1 and 2 feature tri‐ and tetracoordinate Cu^I ions and an additional acetonitrile solvent molecule in the crystal. In 1 , the solvent molecule is coordinated to one copper ion whereas it remains uncoordinated in 2 . The tricoordinate Cu^I ions show a slight pyramidalization at the metal atom and somewhat short contacts to the other tricoordinate Cu^I ion in 2 or the Cu₃‐triangle in 1 . NMR spectroscopy revealed easy decoordination of the acetonitrile ligand from 1 and a dynamic “windshield‐wiper”‐type process that interconverts the differently coordinated phospholide rings of each odpf ligand and the tri‐ and tetracoordinate Cu^I ions.     

A novel method of surface modification on thin-film-composite reverse osmosis membrane by grafting hydantoin derivative

Membrane degradations by biofouling and free chlorine oxidation are the major obstacles for aromatic polyamide thin-film-composite (TFC) reverse osmosis (RO) membranes to realize high performance over a long period of operation. In this work, a hydantoin derivative, 3-monomethylol-5,5-dimethylhydantoin (MDMH), was grafted onto the nascent aromatic polyamide membrane surfaces by the reactions with active groups (e.g., acyl chloride groups) in the surfaces. The grafted MDMH moieties with high reaction activity and free chlorine could play as sacrificial pendant groups when membranes suffer from chlorine attacks, and the chlorination products N-halamines with strong antimicrobial function could sterilize microorganisms on membrane surfaces and then regenerate to MDMH. This was designed as a novel means to improve both chlorine resistances and anti-biofouling properties of the aromatic polyamide TFC RO membranes.Attenuated total reflectance mode Fourier transform infrared spectroscopy (ATR-FTIR) revealed that the MDMH-modified membranes had two characteristic bands at 1772 and 1709 cm⁻¹ corresponding to two carbonyl groups in hydantoin ring. This suggested the successful grafting of MDMH onto the membrane surfaces, which was further confirmed and quantified by X-ray photoelectron spectroscopy (XPS) analysis. After modification with MDMH, the membrane surface hydrophilicity increased obviously as contact angles decreased from 57.7° to 50.4–31.5°. But, there was no obvious change in membrane surface roughness after modification. The MDMH-modified membranes were shown to possess high chlorine resistances with small changes in water fluxes and salt rejections after chlorination with 100–2000 ppm h chlorine at pH 4. The chlorinated MDMH-modified membranes demonstrated obvious sterilization effects on Escherchia coli and substantial preventions against microbial fouling. Therefore, the MDMH-modified membranes offer a potential use as a new type of chlorine resistance and anti-biofouling TFC RO membranes.     

硫酸铵母液除氯及其对结晶影响

硫酸铵母液中Cl^-不断循环富集导致设备腐蚀严重,同时影响硫酸铵结晶及品质。本文运用硫酸钙铝法和脱硫灰铝法分别对硫酸铵母液进行除氯研究,采用筛分法对晶体粒径进行分析、扫描电子显微镜（Scanning Electron Microscope, SEM）对晶体尺寸、形貌进行表征,X射线衍射仪（X-ray Diffractometer,XRD）分析晶体物相。研究表明：除氯剂最佳投加量为3.0 g硫酸钙和0.8 g偏铝酸钠,3.0 g脱硫灰和0.8 g偏铝酸钠,对应除氯率分别为31.70%和36.38%。在转速200 r/min,反应温度为75 ℃,两种除氯剂加入会使ρ（Cl^-）快速下降,此为Cl^-与Ca²⁺和AlO₂^-反应形成了不溶钙铝氯化合物;除氯剂加入过量会使NaAlO₂发生双水解,解离出OH^-,抑制Cl^-与Ca²⁺、AlO₂^-反应,导致Cl^-去除率下降。硫酸钙铝法所产生的钙铝氯化合物会附着在晶粒活性表面进而增大硫酸铵结晶介稳区宽度,抑制晶体正常生长,导致结晶量减少;脱硫灰铝法中杂质金属可将OH^-消耗和减小硫酸铵结晶介稳区宽度,所含大量SO₄^2-会使硫酸铵结晶量增加,但晶体纯度降低。相关研究结果可为减少氨法脱硫设备腐蚀及优化硫酸铵结晶提供参考。