乙二胺四乙酸二钠标准溶液滴定系数测量结果不确定度的评定

0　概述本文对Na2 EDTA标准溶液系数测量结果的不确定度进行了评定,采用容量分析方法标定了Na2 EDTA标准溶液。通过对影响测量结果的不确定度分量的分析和量化,求出被测量Na2 EDTA标准溶液滴定系数的标准不确定度和扩展不确定度,给出各分量对测量结果不确定度的相对贡献,对测量结果进行了表述。1　配制和标定过程按照GB/T815 1. 1- 2 0 0 0配制和标定Na2 EDTA标准溶液方法如下:1.1　称取18.6g乙二胺四乙酸二钠,加水微热溶解,冷却至室温,移入10 0 0mL容量瓶中,用水稀释至刻度,放置三天后标定。1.2　称取0 .10 0 0 g金属锌(≥99.99%…     

水中总硬度测量不确定度评定

一、测量步骤 1．锌标准溶液的配制 准确称取（0．6-0．8）g用酸除去表面氧化物污染的锌粒，完全溶于（1＋1）盐酸中，移入1000mL容量瓶，用纯水定容。[第一段]     

四羟丙基乙二胺和EDTA·2Na盐化学镀铜体系研究

为了降低成本、提高镀层质量和镀液的稳定性,以混合配位体(EDTA·2Na)代替THPED(四羟丙基乙二胺),系统研究了THPED和EDTA·2Na盐双配位体化学镀铜体系.对镀速、镀液稳定性及镀层附着力的研究结果表明,镀速随EDTA·2Na盐、硫酸铜和甲醛浓度的增加先升高后降低;随THPED浓度的增加先降低后升高;随溶液pH值和镀液温度增加而升高;添加剂亚铁氰化钾、α,α'-联吡啶和2-MBT虽均使镀速减慢,但能使镀层外观变好;聚乙二醇-1000(PEG-1000)对镀速影响较小,但能使镀层质量变好.其化学镀铜最佳条件为THPED 10.0 g/L,EDTA·2Na 8.7 g/L,CuSO4·5H2O 12.0 g/L,甲醛(37%～40%)16.0 mL/L,α,α'-联吡啶10.0 mg/L,亚铁氰化钾40.0 mg/L,PEG-1000 1.0 g/L,2-MBT(二巯基苯骈噻唑) 0.5 mg/L,pH值13.2及镀液温度50 ℃.在最佳条件下获得的镀层外观红亮、表面平整,镀液稳定,镀速达到4.05 μm/h.由SEM分析可知,镀层表面平整、光滑、晶粒细致.     

火焰原子吸收法直接测定电镀液中铜和铁离子

本研究采用火焰原子吸收法直接测定电镀槽液中铜、铁离子 ,操作简便 ,分析灵敏度高。用分析纯化学试剂 ,按各镀种主要成分的含量 ,配制空白溶液 ,加入一定量的铜、铁标准溶液 (0 0 1ｍｇ/ｍＬ)进行测量。1　电镀溶液中铜、铁杂质离子的测定镀镉、镀铬电镀液 :移取 5 0 0ｍＬ镀镉电镀液于 5 0ｍＬ容量瓶中 ,用水稀释至刻度 ,混匀后 ,测量吸光度值 ,从工作曲线上查出铜含量。取 2 0 0ｍＬ镀镉电镀液于 2 0 0ｍＬ容量瓶中 ,测定铁含量。碱性锌电镀液 :移取 5 0 0ｍＬ镀镉电镀液于5 0ｍＬ容量瓶中 ,测定铜的含量。移取 5 0 0ｍＬ镀镉电镀液…     

铅锌矿中铅锌的快速配位滴定

研究了用配位滴定法连续测定铅、锌含量的方法。对铅锌离子混合溶液,采用在pH值5~6的缓冲体系中,以邻二氮菲掩蔽锌离子,用EDTA标准溶液单独测定铅,获得了较好的准确度,减少了锰、钴、铜、镍等离子的干扰;然后在不加掩蔽剂条件下测定出铅锌总量从而计算出锌含量。该法实现了对铅锌混合离子的快速准确测定,可用于铅锌矿中铅锌的测定。     

无氰镀锌溶液中氨三乙酸的分析

方法一1.方法要点: 在pH为10的溶液中,用氰化钾掩蔽锌,以邻苯二酚紫为指示剂,用硝酸铅络合滴定测定氨三乙酸(NTA)。2.试剂: (1) 10%KCN; (2) 0.1%邻苯二酚紫水溶液; (3) NH_4OH—NH_4Cl缓冲液(pH10); (4) 0.05M Pb(NO_3)_2标准溶液。标定:取10毫升0.05M EDTA标准溶液于250毫升三角瓶中,加pH10缓冲液10毫升、     

黄铜镀液中铜的光度测定

黄铜镀液中铜的测定常用ＥＤＴＡ滴定法 ,但此法只能测定铜锌合量 ,且许多常见的金属离子如钙、镁等均有干扰。本文用Ｃｕ ＥＤＴＡ光度法测定 ,方法具有良好的选择性 ,且简便快速。1　试剂和仪器铜标准溶液 :准确称取 1.9647ｇ优级纯ＣｕＳＯ4·5Ｈ2 Ｏ溶于水中 ,移入 2 50ｍｌ容量瓶 ,定容并混匀。此液含铜 2ｍｇ/ｍｌ。显色液 :称取 4ｇＥＤＴＡ二钠盐和 7ｇ氯化铵溶于 57ｍｌ氨水中 ,用水稀释至 10 0ｍｌ,混匀备用。分光光度计 :72 1型 (上海第三分析仪器厂出品 ) ,2ｃｍ光程比色皿。2　分析方法( 1)待测液的制备　准确吸取镀液 2 .0 0…     

影响碳纤维表面镀铜速率的因素

在碳纤维表面先化学镀铜再电镀铜可获得具有一定厚度且均匀的铜镀层.研究了甲醛、配位剂、稳定剂等用量、pH值、温度、电流密度、电解时间等对碳纤维增重率的影响,确定了镀铜的最佳配方,并用扫描电镜验证了镀铜效果.结果表明,最佳化学镀铜配方为16 g/L CuSO-4·5H-2O,25 g/L EDTA·2Na,15 g/L酒石酸钾钠,15 g/L NaOH, 5 mg/L 2,2′-联吡啶,15 mg/L K-4Fe(CN)-6,6 mL甲醛(分析纯).本法既较好地解决了碳纤维束的黑心问题,又可获得较厚的镀层,且镀层与碳纤维的结合更牢.     

三乙醇胺和EDTA·2Na盐双络合体系快速化学镀铜T艺研究

系统研究了以三乙醇胺(TEA)为主络合剂、EDTA·2Na盐为辅络合剂的二次镀铜体系.实验结果表明镀速随EDTA·2Na盐浓度增加而减慢,随TEA浓度、硫酸铜浓度、甲醛浓度、溶液pH值和镀液温?快;添加剂亚铁氰化钾、α.α′-联吡啶和2-MBT均能使镀速减慢且浓度较低时均能使镀层外观变好;PEG-1000对镀速影响较小,但能使镀层质量变好.其二次化学镀铜最佳条件是:CuSO4·5H2O为16g/L,EDTA·2Na盐为6g/L,TEA为21.5g/L,pH值为12.75,甲醛(37%～40%)为16ml/L,亚铁氰化钾为100mg/L,α,α′-联吡啶为20mg/L,PEG-1000为1g/L,2-MBT为0.5mg/L及镀液温度为50℃.在最佳条件下镀速达到10.57μm/h,SEM分析镀层表面光滑、结晶均匀.     

用双波长分光光度法测定锡铜锌合金镀液中铜、锌的含量

锡铜锌合金镀层已广泛应用于电子和机械产品的防护,为此,以5-Br-2-吡啶偶氮-5-二乙氨基酚(5-Br-PADAP)为显色剂,采用双波长分光光度法对新型环保锡铜锌合金镀液中的铜、锌含量进行同时测定.Cu2 的测量波长是555 nm,参比波长是561 nm;Zn2 的测量波长是538nm,参比波长是568 nm.试验考察了酸度、甘油用量、显色剂用量、OP乳化剂用量以及干扰离子对测定的影响.结果表明:铜、锌含量在0～20μg/25 mL范围内均服从郎伯-比尔定律,样品加标回收率为98%以上.该方法简便、快速,准确度高,不经分离可直接对锡铜锌合金镀液中的铜、锌进行快速测定,结果令人满意.     

改性沸石对电镀废水中Pb2+、Zn2+、Ni2+的吸附

将天然沸石进行处理制备出多孔质改性沸石颗粒。在静态条件下，研究了改性沸石颗粒对重金属离子Pb^2 ,Zn^2 ,Ni^2 的吸附效果及条件，含Pb^2 ,Zn^2 ,Ni^2 的电镀废水经改性沸石颗粒吸附后，废水中Pb^2 ,Zn^2 ,Ni^2 的含量低于国家排放标准。     

NpO 2 + -UO 2 2+ cation-cation interaction in NaCl-KCl-CsCl and LiCl-KCl-CsCl eutectic melts

Absorption spectra of the NpO ₂ ⁺ ion in UO ₂ ²⁺ -containing NaCl-KCl-CsCl (0.300:0.245:0.455) and LiCl-KCl-CsCl (0.575:0.165:0.260) eutectic melts in the region of the 5f-5f transitions, 700–2000 nm, were studied at 650 and 500°C, respectively. Processing of the spectra allowed the previously discovered phenomenon, cation-cation interaction of actinides in melts, to be interpreted for the first time in terms of the mass action law. It was shown that, at the concentrations of the interacting components studied (C _Np = 0.2 M and C _U = 0.1–2 M), a 1: 1 NpO ₂ ⁺ ·UO ₂ ²⁺ cation-cation complex is formed. Its concentration stability constant was estimated at 0.06(6) and 0.11 1 mol^?1 for the NaCl-KCl-CsCl and LiCl-KCl-CsCl systems, respectively.     

胶团强化超滤中SDS胶团对Cd^2＋，Zn^2＋和Pb^2＋的竞争吸附

胶团强化超滤法是一种将表面活性剂技术和超滤技术结合的新型、高效的重金属废水治理方法.以十二烷基硫酸钠(SDS)为表面活性剂,对含单一镉、锌、铅溶质以及混合溶质体系进行了胶团强化超滤研究,考察了胶团对Cd2 ,Zn2 ,Pb2 的竞争吸附性能.研究发现,当溶液中多种二价重金属离子存在时,各离子之间存在与SDS胶团的竞争吸附,竞争能力为Pb2 ＞Zn2 ＞Cd2 ;Cd-Zn有明显的协同吸附效应,而Cd-Pb,Zn-Pb则表现为拮抗吸附.     

On the Eu2+-Mn2+ energy transfer in BaMgF4

Energy transfer from Eu²⁺ to Mn²⁺ ions is shown to occur in BaMgF₄ : Eu, Mn crystals. The efficiency of this transfer is moderate. This is attributed to the fact that Eu²⁺ and Mn²⁺ ions are distributed randomly in the host lattice. Quantitative evaluation leads to the suggestion that the transfer is restricted to only seven neighbors at 4.0 Å and is thus exchange mediated.     

Observable effects of Ca2+ buffers on local Ca2+ signals

Calcium signals participate in a large variety of physiological processes. In many instances, they involve calcium entry through inositol 1,4,5-trisphosphate (IP(3)) receptors (IP(3)Rs), which are usually organized in clusters. Recent high-resolution optical experiments by Smith & Parker have provided new information on Ca(2+) release from clustered IP(3)Rs. In the present paper, we use the model recently introduced by Solovey & Ponce Dawson to determine how the distribution of the number of IP(3)Rs that become open during a localized release event may change by the presence of Ca(2+) buffers, substances that react with Ca(2+), altering its concentration and transport properties. We then discuss how buffer properties could be extracted from the observation of local signals.     

ESR of Cu2+and Tl2+ in thallium borate glasses

The electron spin resonance (ESR) and optical absorption spectra of Cu²⁺ were measured in thallium borate glasses in order to investigate the effects of glass transition temperature,T _g, upon the responses of cupric ion in alkali borate glasses. The ESR of Tl²⁺ induced by-ray irradiation was also obtained. An abrupt increase in the covalency of in-plane Cu²⁺-O-bonding was observed in the Tl₂O system as well as in the Na₂O system in a similar B₂O₃ composition range althoughT _g for the Tl₂O glasses has little dependency on the composition compared with the Na₂O glasses. The trend in the variation of the S-character of the Tl²⁺ unpaired electron with composition agreed with that of the covalency of in-plane Cu²⁺-O-bonding. The structure of the anion group present in Tl₂O glasses was also examined by laser reman spectroscopy.     

酸改性膨润土吸附去除镍镉离子的研究

在静态条件下,研究了改性膨润土对重金属离子的吸附性能和吸附机理,着重探讨了改性膨润土去除模拟水样中重金属离子Ni2 ,Cd2 的适宜条件及改性膨润土的再生方法.结果表明,改性膨润土对Ni2 ,Cd2 具有较好的吸附性能;pH值是影响改性膨润土对重金属离子吸附的重要因素,不同的金属离子都有其适宜的pH值范围.吸附的最佳条件是pH值5.0～7.0,废水中Ni2 ,Cd2 含量不大于45 mg/L,搅拌时间约60 min.利用改性膨润土吸附处理Ni2 ,Cd2 含量小于45 mg/L的模拟水样,效果很好,Ni2 ,Cd2 的去除率均可分别达到98.5%以上,出水可达到国家排放标准.     

锰矿尾渣对Cu2+和Ni2+的吸附性能研究

研究了锰矿尾渣对重金属离子Cu2 和Ni2 的吸附性能,分析了锰矿尾渣的吸附动力学,就吸附时间、Cu2 和Ni2 浓度及pH值等因素对锰矿尾渣吸附性能的影响作了系统考察,并对锰矿尾渣的吸附机理进行了初步探讨.结果表明,在温度为25°℃、pH值为7.5的条件下,锰矿尾渣对Cu2 和Ni2 的吸附容量可达到1.6 mg/g以上,去除率均可达到97.5%以上,适宜于处理含低浓度Cu2 或Ni2 的废水.锰矿尾渣的吸附机理为离子交换吸附和表面配位吸附.     

Characterization of various Eu2+ sites in Ca2SiO4:Eu2+ and Ba2SiO4:Eu2+ by high-pressure spectroscopy

Photoluminescence of Ba₂SiO₄ and Ca₂SiO₄ activated with Eu²⁺ was investigated at various temperatures (from 10 K to 300 K) and pressures (from ambient to 200 kbar). At ambient pressure and room temperature, under UV excitation both phosphors yielded a green emission band with maxima at 505 nm and 510 nm for Ba₂SiO₄ and Ca₂SiO₄, respectively. The energies of these bands depended on pressure; the pressure shifts were ?12:55 cm^?1/kbar for Ba₂SiO₄:Eu²⁺; and ?5:59 cm^?1/kbar for Ca₂SiO₄:Eu²⁺. In the case of Ca₂SiO₄:Eu²⁺, we observed additional broadband emission at lower energies with a maximum at 610 nm (orange band). The orange and green emission in Ca₂SiO₄:Eu²⁺ had different excitation spectra: the green band could be excited at wavelengths shorter than 470 nm, whereas the orange band — at wavelengths shorter than 520 nm. The pressure caused a red shift of orange emission of 7.83 cm^?1/kbar. The emission peaked at 510 nm was attributed to the 4f⁶5d→4f⁷(⁸S₇₌₂) transition of Eu²⁺ in the β — Ca₂SiO₄:Eu²⁺ phase, whereas the emission peaked at 610 nm — to the γ — Ca₂SiO₄:Eu²⁺ phase. The emission of Ba₂SiO₄:Eu²⁺ peaked at 505 nm was attributed to the 4f⁶5d→ 4f⁷(⁸S_7/2) transition of Eu²⁺ in the β — Ba₂SiO₄ phase.