在FAAS分光光度法中利用CTMAB-7-甲基喹啉对Fe的增敏作用测定精锌中的微量铁

本文研究了以CTMAB-7-甲基喹啉为体系与铁形成的三元络合物对铁的增敏效果,增敏百分数可达到52%,并且方法简单、快速、准确,有很好的应用价值。     

Zr-PV-CTMAB三元络合物分光光度法测定铝合金中锆

以三元络合物分光光度法测定锆的显色剂有二甲酚橙、偶氮胂Ⅲ、水杨基萤光酮和偶氮氯膦等。本文研究了Zr与PV(邻苯二酚紫)的显色条件以及pH在5.3～6.5时,Zr—PV络合物分别与GTMAB(溴化十六烷基三甲基铵)、CPB(溴化十六烷基吡啶)和CPC(氯化十六烷基吡啶)形成三元络合物的增敏反应。发现,三种表面活性剂的增感效能基本相同,故本文仅对Zr—PV—CTMAB体系做了进     

DBC－偶氮胂双波长增敏法测定球墨铸铁中稀土

ＤＢＣ－偶氮胂双波长增敏法测定球墨铸铁中稀土李维翰,谌文华（武汉钢铁学院,武汉,４３００８１）（武汉钢铁公司,４３００８０）测定微量稀土的显色剂很多,ＤＢＣ－偶氮胂是一种新显色剂,与铈组稀土元素形成稳定的蓝紫色络合物,络合物中稀土与ＤＢＣ－偶氮脾的组...     

萃取分光光度法测定铅钛合金中的钛

试验在１．８ｍｏｌ／Ｌ盐酸介质中，钛与二安替比林甲烷形成黄色络合物，引络合物与二氯化锡作用形成疏水性的三元络合物，以三氯甲烷萃取，于４００ｎｍ处测定钛，方法准确、可靠，适合于万分之一至百分之一钛的测定。     

丁基罗丹明B—磷钼钒杂多酸—乳化剂光度法测定钒

碱性染料—杂多酸多元络合物光度法正在深入研究和扩大应用范围。本试验是钒(V)与磷钼酸盐形成钒钼黄,此络合物与碱性染料—丁基罗丹明B进一步形成增水性离子缔合物。为提高选择性和稳定性,增加酸度并采用硫磷酸—盐酸羟胺介质分解过剩杂多酸,用羧甲基纤维素钠作分散剂,钒量1～12微克/100毫升符合比尔定律。本法灵敏度高ε=1.3×10~5,应用于矿石中钒的测定。     

微乳液增敏水杨基荧光酮分光光度法测定微量铟

研究了多种胶束及微乳液对水杨基荧光酮光度法测定铟的增敏作用,并选择增敏作用最强的OP微乳液作为铟测定的增敏试剂。水杨基荧光酮与铟的显色反应的研究结果表明,在OP微乳液存在下,铟与水杨基荧光酮在醋酸-醋酸钠介质中形成一种橙红色络合物,络合物的最大吸收峰位于522 nm波长处,表观摩尔吸光系数为ε=1.91×105L.mol-1.cm-1,铟含量在0~2.0μg/mL范围内符合比尔定律。所制定的方法用于纯铅中微量铟的分析,相对标准偏差为2.7%(n=6),加标回收率为102%。     

分光光度法测定工业硅中铁,铝

在盐酸介质中，铁与邻菲罗啉形成橙红色络合物，其最大吸收峰在５１０ｎｍ处；铝与铬天青Ｓ形成紫红色络合物，其最大吸收峰在５５０ｎｍ处。方法灵敏度高、稳定性好，达到标准要求。     

极谱络合吸附波的进展及在冶金分析中的应用和研究

络合吸附（包括催化）波作为灵敏的示波极谱测定方法,在我国各工业部门已被广泛应用。近来研究结果表明,在加入一定量表面活性剂或其它增效试剂,如：加第二元素（形成异多核络合物）或加第二和第三配位体（形成多元络合物）后,这类方法的灵敏度、选择性和稳定性可被进一步提高。本文对络合吸附波的这些进展进行了综述。表明研究增敏机理和规律,开发和建立新的高灵敏分析方法,仍是一个重要目标;可以看出络合吸附波正在推陈出新。     

分光光度法测定钢铁中钴

分光光度法测定钢铁中钴王怀生，崔慧，张国荣（山东省聊城师范学院化学系，聊城，２５２０５９）由于Ｃｏ２＋与ＳＣＮ－形成的络合物稳定性较差，所以在水相不显色，通常是将Ｃｏ２＋与ＳＣＮ－形成的络合物用有机溶剂萃取后测定［１］，或者将Ｃｏ２＋与ＳＣＮ－形成的...     

钒—9—（3,5—溴）水杨基荧光酮—溴化十六烷基三甲基铵显色反应的应用

研究了钒-9（3，5-二溴）水杨基荧光酮-CTMAB三元络合物的显色反应条件。在pH5.5的六次甲基四胺-HCl缓冲溶液中，钒与试剂形成1∶2的络合物，其最大吸收波长λ     

X射线光电子能谱分析电工钢板铬酸盐涂层中铬形态

使用X射线光电子能谱(XPS),对电工钢板铬酸盐涂层中的元素组成及铬元素的价态进行了研究,并对其形成机理进行了探讨。结果表明,涂层中主要含有Cr、O、Mg、Al、B以及C元素。在给定的处理工艺条件下,铬酸盐涂层钢板中铬元素主要是以Cr2O3,CrO3形态存在,在检测中没有发现零价铬。     

铬酸钡分光光度法测定高硫铝土矿中硫酸根

硫化物形态的硫含量是铝土矿选矿关注的指标,而其含量常采用总硫减去硫酸根含量的方式计算得出,因此测定高硫铝土矿中硫酸根的方法受到关注。采用盐酸(1+1)分解高硫铝土矿,氨水沉淀法分离铝和铁,碳酸铵沉淀法分离钙,过滤,在酸性溶液中,加入铬酸钡悬浊液与硫酸根生成硫酸钡沉淀和铬酸根离子,用氨水调节pH值至9~10,过滤除去多余的铬酸钡和生成的硫酸钡,滤液即为被硫酸根所置换出的铬酸根溶液,采用铬酸钡分光光度法进行测定,通过铬酸根的吸光度值间接计算出硫酸根的含量,实现了对高硫铝土矿中硫酸根的测定。对显色条件进行了优化,结果表明,硫酸根质量浓度在1~200μg/mL范围内与其对应的吸光度呈线性关系,线性相关系数为0.9999,检出限为0.36μg/mL。将实验方法用于高硫铝土矿实际试样中硫酸根的测定,结果的相对标准偏差(RSD,n=6)为1.6%~1.8%,回收率为95%~105%。分别采用实验方法和重量法对高硫铝土矿中硫酸根进行测定比对,二者结果基本一致。     

Organo-Illite as a Low Permeability Sorbent to Retard Migration of Anionic Contaminants

Landfill leachate, often having high concentrations of metal cations, anions, and organic compounds, presents a great threat to nearby groundwater. Due to negative charges on soil particles, regular clay liners cannot effectively retard the movement of anionic contaminants such as chromate. In this paper, a natural illite was modified by cationic surfactants with different chain lengths and tested for its chromate removal efficiency. When the surfactant tail group is relatively short and the solution critical micelle concentration is high, the sorbed surfactant molecules form a monolayer on illite, resulting no chromate sorption by the organo-illite. As the chain length of surfactant tail group increases, the critical micelle concentration reduces and the surfactant molecules sorb as admicelles on illite with the surfactant sorption exceeding the illite’s cation-exchange capacity. Such admicelle modification makes the organoclay capable of retaining chromate instantaneously and retarding the movement of chromate by 1–2 orders of magnitude. The illite’s hydraulic conductivity showed a slight increase after surfactant modification, from 1×10?7 to 8×10?7?cm/s, probably due to reduced packing density after modification. Chromate breakthrough data from column transport experiments were well described by a one-dimensional advection-dispersion model that incorporated Langmuir sorption.     

Influence of Solution pH and Ionic Strength on Chromate Uptake by Surfactant-Modified Zeolite

In this study, the influence of solution pH and ionic strength on sorption of chromate by surfactant-modified zeolite was tested. The sorption of chromate followed a Langmuir isotherm under different pH and ionic strength conditions. However, as the solution pH and ionic strength increased, the Langmuir sorption coefficient of chromate decreased systematically, reflecting an increased competition of background electrolyte anions against chromate for sorption sites. The chromate sorption maximum also decreased slightly as the solution pH and ionic strength increased. The stoichiometric relationship between chromate sorption and counterion desorption further indicated that chromate sorption on surfactant-modified zeolite surfaces was mainly due to surface anion exchange. In addition, increases in background electrolyte reduced counterion desorption and resulted in a better surfactant bilayer formation.     

Investigation of the Effects of some Parameters in the Production of Chromate from Chromite Ores in Iskenderun Region

The conversion of chromite ore from iskenderun region into chromate was investigated. Firstly, the chromite ore was analysed using conventional chemical methods. Then, the effect of some parameters such as roasting time, temperature and the amount of additives on the conversion efficiency to the chromate was examined. The optimum roasting conditions were determined as 300°C, 2 hours, 10 times the stoichiometrically required amounts of NaClO₃ and 6 times the stoichiometrically required amounts of KOH. Under these conditions, the maximum recovery of chromate was found to be 100%. The product obtained from the roasting process was leached with water to produce a clean chromate solution. The effect of temperature and solid/liquid (S/L) ratio was investigated in the water leaching experiments. The optimum experimental results obtained were 100% at a 1:5 solid to water ratio at 25°C and 20 min leaching period. The chromate solution was purified using conventional purification processes.     

Cationic polymers for selectivity control in the capillary electrophoretic separation of inorganic anions

The capillary electrophoretic (CE) separation of the inorganic anions bromide, chloride, nitrate, nitrite, fluoride, sulfate and phosphate is described in 0.005 mol/L sodium chromate electrolyte in the presence of soluble polydisperse ionic polymers (polyelectrolytes). The cationic polyelectrolytes used were as follows: poly(1,1-dimethyl-3,5-dimethylenepiperidinium) chromate, hexadimethrine chromate, poly(1,1-dimethyl-3,5-dimethylenepyrrolidinium) chromate and ((diethylamino)ethyl)-dextran chromate in the concentration range 0.004-0.6% (w/v). These polyelectrolytes were shown to be capable of reversing the direction of the electroosmotic flow as well as inducing changes in analyte electrophoretic mobility, separation selectivity, and resolution. Changes in electrophoretic mobility by as much as 25% were observed for the sulfate anion, and the resolution of fluoride and phosphate was enhanced by a factor of 7.8. In the presence of 0.05-0.17% w/v poly(1,1-dimethyl-3,5-dimethylenepyrrolidinium) chromate at pH 8, separation currents were found to increase only slightly as compared to an electrolyte containing equivalent amounts of sodium chromate. Electroosmotic flow was also found to be fairly constant (+/- 16%) in the pH range 6.55-10.02 for 0.01% (w/v) poly(1,1-dimethyl-3,5-dimethylenepiperidinium) chromate at an ionic strength of 0.04, compared to a 400% change in the absence of the polyelectrolyte. The reproducibility of the electroosmotic mobility was between 0.36 and 6% RSD, and analyte electrophoretic mobility was between 0.01 and 1.6% RSD. Peak height reproducibility was 0.2-8.0% RSD. Separation efficiencies were between 258,000 and 780,000 theoretical plates, and detection limits were between 4.4 x 10(-7) and 9.1 x 10(-6) mol/L.     

便携式X射线荧光光谱仪分析镀锌板铬盐钝化膜涂镀量

镀锌板铬盐钝化膜涂镀量是生产工艺控制和膜厚度质量控制的一个重要指标,为提高现场质量控制效率、降低质量控制成本,急需一种无需复杂样品前处理、实现涂镀量实时在线分析的方法。实验采用圆片取样机制样法制取标样,建立了用便携式X射线荧光光谱(PXRF)对镀锌板铬盐钝化膜涂镀量进行实时、在线定量分析的方法。铬盐钝化膜涂镀量与Cr元素含量存在对应关系,实验通过分析Cr元素来表征钝化膜涂镀量。为获得镀锌板铬盐钝化膜体系中Cr元素的最佳激发效果,比较了5种不同分析条件,并确定采用电压15kV、电流10μA作为实验的分析条件;研究了元素谱线之间的干扰重叠校正以及基材元素对待测元素的干扰,采用α经验系数法进行基体校正,避免基体元素Zn和Fe两种元素对Cr元素分析准确度的影响;讨论了检出限的计算方法,采用涂镀量低的样品作为测试样,根据多次测试结果的标准偏差来计算检出限,铬盐钝化膜涂镀量的检出限值为0.92mg/m²;对方法的精密度进行考察,相对标准偏差(RSD)控制在1.5%之内;经与电感耦合等离子体原子发射光谱法(ICP-AES)进行比对,相对误差控制在2.5%之内,方法的准确度能够满足现场质量控制要求,实现了样品的实时、在线分析,提高了测试效率。     

On conversion coating treatments to replace chromating for Al alloys: Recent developments and possible future directions

Anticorrosive protection of Al alloys still depends heavily on the use of chromates, which are widely and universally employed as chromate conversion coating and chromic acid anodising pretreatments. The replacement of chromate based treatments with more environmentally compliant processes and materials has been identified as a high priority. The aim of this paper is to review the most recent developments in the application of common inorganic protection layers based on conversion coatings for Al alloys. The review lists and discusses the majority of conversion coatings, including those formed through anodisation, on Al alloys as potential replacements to the most widely used treatments based on chromate chemistry.     

铬酸钡分光光度法测定铁矿石中硫

铁矿石中硫含量影响到成品钢质量,因此硫含量的快捷准确测定极其重要。在780 ℃下碳酸钠和氧化锌混合熔剂半熔铁矿石样品,将其中的硫转换为硫酸盐后,用沸水溶解硫酸盐并过滤,同时用20 g/L热碳酸钠溶液多次洗涤沉淀,用铬酸钡分光光度法测量滤液中硫酸盐含量,从而建立了分光光度法测定铁矿石中硫含量的方法。条件优化试验表明:需用热的碳酸钠溶液洗涤沉淀与烧杯才能保证铁矿石中的SO₄^2-全部留存在液体中;添加铬酸钡溶液后煮沸时间应大于2 min才能保证铬酸钡全部转化为硫酸钡;添加铬酸钡煮沸后的溶液需用氨水(1+1)调至pH值大于10,Cr(VI)才能完全以CrO₄^2-的形式存在,从而不影响测定结果。铁矿石中硫质量分数为0.014 %~0.30 %时与吸光度呈线性关系,线性相关系数为0.999 3。方法检出限为0.003 7 %,定量限为0.026 0 %,表观摩尔吸光系数为5.75×10² L·mol^-1·cm^-1。为了验证硫元素不同存在形态的测定偏差,按照实验方法对单质硫、亚硫酸钠、硫酸钠、硫化亚铁以及铁矿石的标准物质分别进行测定,测定结果的相对误差为-3.63%~3.77%。选择3个实验组,按照实验方法对铁矿石中硫含量进行测定,每个实验组分别按照实验方法平行测定7次,结果的相对标准偏差(RSD,n=3)为3.7%,测定结果与国标法GB/T 6730.16—2016中硫酸钡重量法相吻合。     

镁合金无铬转化处理技术的研究进展

针对传统铬酸盐化学转化处理溶液中通常含有毒性且致癌的六价铬,为保护环境及实现人类的可持续发展,近来国内外科技人员研究很多新型镁合金无铬的转化膜技术。希望取代镁合金的铬酸盐处理。据此,综述了国内外镁合金几种无铬转化处理技术的进展及现状,指出了目前镁合金无铬化学转化处理技术中存在的一些问题,展望了该技术的发展前景。