Effects of sulfurous acid on anodic process of gold electrode in thiourea solution

Thioureaitselfisunstableunderanappropriateoxidizingconditionandcanbeoxidized .Theoxida tion productsofthioureadependontheoxidants ,suchashydrogenperoxide ,ferriciron .Itwasreport edthatwithferricironetc ,thioureadecomposedasfollows[7] .2SC(NH2 ) 2 (SC(NH)NH2 ) 2 + 2H++ 2e(2 )ThepotentiodynamicpolarizationcurvesshowninFig .1wereobtainedin 0 .0 5mol/Lthiourea(TU )solutionforafreshlygroundstationarygoldelectrodestartsfrom 0to 1.2 0VvsSCE .FromFig .1itcanbeseenthatthefirstanodicshoulderais…     

STUDY ON SELECTIVE DISSOLUTION OF GOLD IN ALKALINE THIOUREA MEDIA

Manyresearches[1-3)ondissolutionofgoldinacidicsolutionsofthioureahavebeenreportedsincePlaksin.Generally,itwasconsideredthatthereaction(1)resultsindissolutionofgoldinthioureasolution.An[CS(NH,)sj' e~An ZCS(NH,)2E'~0.38V(1)NH,(NH)CSSC(NH)NH, ZH Ze~ZCS(NH,),E0-0.42V(2)CharleyWRetalthoughtthatthereaction(2)occurredfastly,theproductformamidinedisulfidewasanactiveoxidantandwasveryimportantduringthedissolutionofgold@@['j.However,theconclusionswerelimitedonlyinacidicthioureadissolutio…     

Electrode process of diethyldithiocarbamate on surface of pyrrhotite

1INTRODUCTION Inthepastdecade,muchprogresshasbeen madeinunderstandingthereactionsofasulfidemineralsurfacewithxanthateagents.Manyelec trochemicaltechniqueshavebeenemployedto studythereactionmechanismofsulfideminerals(suchaspyrite,galenaandchalcopyrite)with xanthatereagents[14].Theseinvestigationsindi catethattheoxidationofboththemineralandthe collectorplaysanimportantroleintheflotationprocess.Itisgenerallybelievedthatthereactions producethehydrophobicparticlesurfacesrequired inflotation.It…     

巯基自组装修饰恒电位共价键合法固定基因电化学传感器的制备与表征

以金电极为基体电极,采用巯基乙醇自组装法制备了巯基乙醇自组装膜修饰电极,再以碳二亚胺为交联剂用控制电位共价键合法将DNA固定在巯基乙醇单分子层上形成了基因修饰电极。以亚甲蓝为电化学杂交指示剂,采用循环伏安法、微分脉冲伏安法等电化学方法对基因电化学传感器进行了表征。结果表明,该方法能够将DNA稳定地固定于电极表面,可用于制备自组装修饰基因电化学传感器。     

001A强酸性树脂吸附硫脲金的研究

研究了强酸性苯乙烯系阳离子交换树脂００１－Ａ在ｐＨ＝ ２．０的Ｈ２ＳＯ４－ ＣＳ（ＮＨ２）２－ Ｈ２Ｏ２ 体系中,吸附、富集硫脲金的性能。结果表明,该树脂对硫脲金离子Ａｕ（Ｔｕ）＋２ （Ｔｕ＝ 硫脲）具有吸附率高,吸附容量大等优异性能。Ａｕ 负载柱可用Ｎａ２Ｓ２Ｏ３ 溶液定量洗脱,用过的树脂可再生。     

Electrochemical kinetics of gold dissolving in alkaline thiourea solution

1 INTRODUCTIONEssentially , determination of electrode reac-tion mechanism is just the determination of thecourse of electrode reaction and the rate-determi-ning step[1 5]. Based on the previous results[6 11],gold dissolution mechanism undergoes the follow-ing courses in alkaline thiourea solution: adsorp-tion of thiourea on active points of electrode sur-face and formation of Au[SC(NH2)2]ads; chargetransfer fromactive gold atomto thiourea moleculeand formation of Au[SC(NH2)2]a+ds; Au-…     

类钙钛矿型La2-xSrxNiO4+δ对氧还原的催化作用及其动力学

合成了La2-xSrxNiO4+δ(0≤x≤1)系列类钙钛矿复合氧化物,并将其作为催化层电极材料制备了空气电极.对电极的极化曲线和循环伏安曲线的测定结果表明,La2-xSrxNiO4+δ型类钙钛矿复合氧化物电极材料对氧还原具有较好的催化活性;并且随Sr的掺杂量的不同,材料的催化活性也有所不同.循环伏安和交流阻抗技术对电极反应动力学特征的研究结果表明,电极反应除受电化学步骤控制外,扩散过程也是整个电极过程的控制因素.     

Preparation, optical properties and cell staining of water soluble amine-terminated PAMAM G2.0-Au nanocomposites

The solution chemical and optical characteristics of formation of amine-terminated polyamidoamine dendrimer G2.0（NH2-PAMAM G2.0）-Au nanocomposites in the aqueous solution of NH2-PAMAM G2.0 at various mole ratios of Au（Ⅲ） to NH2-PAMAM G2.0 were studied by both UV-visible spectrometry and fluorospectrometry. The NH2-PAMAM G2.0-Au nanocomposites, with a type of structure in which one Au nanoparticle is surrounded by several NH2-PAMAM G2.0 dendrimers, emit strong bluish violet fluorescence, and are uniform, water soluble and biocompatible as well as very stable in frozen conditions. The size of gold nanoparticles in the nanocomposites is about 2.5 nm and decreases with the increase of NH2-PAMAM G2.0 concentration. The NH2-PAMAM G2. 0 plays an important role in acting as host or micro-reactor for Au（Ⅲ） before Au（Ⅲ） reduction and acting as dispersant and stabilizer for gold nanoparticles after Au（Ⅲ） reduction. Preliminary experiments of cells staining to human embryonic lung fibroblast cell lines show that the NH2-PAMAM G2.0-Au nanocomposites can be used as optical imaging markers for bioanalyses and medical diagnoses.     

Chemial Bond and Stability of Adsorption of [Au(AsS_3)]~(2-)on the Surface of Kaolinite

1　IntroductionKaoliniteisoneofthemostwide spreadphyllosili catesintheearthcrust.Thegoldiscloselyrelatedtoclayinmanysubmicrometergoldminerals .Itisimportanttostudytheinterrelationbetweengoldandclayforunder standingthecloseassociationofgoldandclaymineralsa…     

Electrochemical behaviors of gold and its associated elements in various complex agent solutions

1　INTRODUCTIONGoldisquitestableanddifficulttodissolveinacommonmineralacid .However ,becausethereisadelectroniclayerunfilledingoldatomicstructure ,goldcanbecombinedwithmanychemicalagentstoformstablecomplexions,causingthepotentialofgoldinasolutiontodecreaseandgoldtodissolveinthesolutioneasily .Basedonthisprinciple ,cyanideisanefficientlixiviatingagentofgold ,andhasbeenwidelyusedtoextractgoldfrom primaryandsecondaryresources .However ,itisthemosttoxicandnotbeneficialtoen vironmentprotection…     

用金的阳极溶解方法研究氯化钠在硫代硫酸盐浸金过程中的作用

用极谱法研究了金在不同浓度的S_2O_3~(2-)溶液及其中加氨、加Cl~-以及同时加氨和Cl~-的阳极溶解行为。结果表明,在前两种溶液中的行为与文献基本一致,在加Cl~-的溶液中的行为与加氨的类似,电流峰值较加氨时的高,同时加氨和Cl~-的溶液则可得到更高的电流峰值,但氨和Cl~-的浓度应相互配合。说明Cl~-与NH_3在金的阳极溶解中的作用类似,但作用更强,尤其是NH_3与Cl~-有适当的浓度比时。     

Study on mechanism of gold leaching by thiourea in the presence of sodium sulphite

Ｃｙａｎｉｄａｔｉｏｎｈａｓｂｅｅｎｕｓｅｄｆｏｒｍｏｒｅｔｈａｎｏｎｅｈｕｎ ｄｒｅｄｙｅａｒｓｉｎｇｏｌｄｉｎｄｕｓｔｒｙｓｉｎｃｅｔｈｅｆｉｒｓｔｐａｔｅｎｔｂｙＭａｃＡｒｔｈｕｒａｎｄｔｈｅＦｏｒｒｅｓｔｓｉｎ 1889[1] ,ａｎｄｓｔｉｌｌｒｅｍａｉｎｓｔｈｅｍｏｓｔｐｏｐｕｌａｒｏｐｔｉｏｎｆｏｒｐｒｏｃｅｓｓｉｎｇｇｏｌｄｏｒｅｓｂｅｃａｕｓｅｏｆｉｔｓｐｒｏｃｅｓｓｓｉｍｐｌｉｃｉｔｙａｎｄｏｐｅｒａｔｉｏｎｅｃｏｎｏｍｙ .Ｎｅｖｅｒｔｈｅ ｌｅｓｓ,ａｐｐｌｉｃａｔｉｏｎｏｆｔｈｅｔｅ…     

交流电场作用下微电极表面电渗流流速的计算

为解决微流体在交流电场作用下电极表面电渗流的流速计算方法,在电极极化产生双电层的基础上,建立了交流电渗等效电路模型,通过对双电层容抗和溶液电阻的计算,得出了微电极表面交流电渗流流速的计算公式,并对各点交流电渗流速与频率的关系进行了分析.结果表明,电极参数为宽80μm,长2 mm,电极间距20μm的对称电极交流电渗,在电极表面上的各点电渗流流速与输入信号频率对数呈正态分布状态.研究结果为交流电渗驱动微流体提供了理论参考依据.     

3 巯基丙酸自组装金电极的制备及其对尿酸的电化学

采取自组装的方法制备3 巯基丙酸（3 mercaptoacetic propionic acid,MPA）自组装膜修饰金电极,进而采用循环伏安、交流阻抗等电化学方法对该电极进行表征,计算电极有效表面积为1.97×10-2 cm2.研究了尿酸（uric acid,UA）在该修饰电极上的电化学行为,结果表明,MPA/SAM/Au电极具有良好的稳定性和电化学活性,在pH=6.0的磷酸氢二钠 柠檬酸（Na2HPO4 C6H8O7）缓冲溶液中,相比裸金电极,MPA/SAM/Au电极对UA响应的峰电流较大.其氧化峰电流与尿酸的浓度在1.6×10-4～1×10-6 mol/L浓度范围内呈良好的线性关系,线性回归方程为ip/(μA)=0.738 9+0.040 46 c0/(μmol/L),相关系数R=0.998 6,检测限为5×10-7 mol/L.     

Optimization of efficient stable reagent of alkaline thiourea solution for gold leaching

1　INTRODUCTIONThiourea ,asanontoxic goldleachingreagentsubstitutingcyanide ,hasattractedtheinterestofmanyresearchersallovertheworldsincethedissolu tionofgoldinthioureasolutionwasfirstreportedin194 1,andaseriesofstudiesonthetheoryandtech nologyforleachinggoldbythioureahavebeencon ducted[1 3] .Mostreportson golddissolutioninthioureasolutionwereconcernedwithacidicmedia .Itwasdifficultforgoldtodissolveinalkalinesolutionbecauseofthepassivationofelementsulfurproducedbytheirreversibledecompositi…     

SELECTIVE DISSOLUTION OF GOLD IN AN ALKALINETHIOUREA SOLUTION BY ELECTROLYSIS

Thioureawaswellknownasanlixiviantforgoldearlyin1932[fi.Thedissolutionofgoldinacidicthioureasolutionwasreportedin1941byPlaksin[Zj.Thioureahasbeenwidelypaidattentiontoasahighselectivenontoxicnovellixiviantofgoldsince197013j.Electrochemicalexperimentsongoldelectrodeshavebeenconductedbymanyresearches,showingthatgolddissolutionbythioureaismoreefficientinacidicsolutionthaninneutralandalkalinesolutions[4j.Theprocessforextract'inggoldfromtheoreorscrapbyacidicthioureasolution,however,demandedexcessive…     

静电纺丝法制备聚苯胺/醋酸纤维素膜修饰电极

利用聚苯胺和醋酸纤维素为原料,按一定的配比配制成溶液,通过静电纺丝法修饰于铂电极表面,制备成聚苯胺/醋酸纤维素(PANI/CA)纳米纤维薄膜修饰电极(PANI/CA/Pt).采用各种电化学方法和扫描电镜(SEM)对PANI/CA纳米纤维薄膜进行了表征,并且用交流阻抗法分析了其在电极表面的动力学过程.结果表明PANI/CA纳米纤维薄膜电化学性质稳定,该修饰电极在H2SO4溶液中呈现出聚苯胺的特征峰,其SEM图显示PANI/CA纳米纤维在电极表面呈网状不规则立体分布,为构建生物传感器提供了一个良好的界面.以此为基础制备的葡萄糖氧化酶/聚苯胺/醋酸纤维素(GOx/PANI/CA/Pt)传感器对葡萄糖有良好的响应,有望制成物美价廉的生物传感器.利用静电纺丝法制备纳米纤维薄膜修饰电极并用来固定酶等蛋白质类高分子物质是一种新的可行性的方法.     

形貌对ZnS微纳结构电化学电极特性影响及机制分析

在低能耗条件下以水热法实现了对ZnS材料的形貌调控,通过扫描电子显微镜及透射电子显微镜表征证明了所获得的ZnS材料为纳米颗粒、微米块和毛线球三种形貌。X射线衍射结果表明ZnS纳米颗粒及ZnS微米块为闪锌矿结构,ZnS毛线球为纤锌矿结构。以三种形貌的ZnS材料分别构建了电化学电极,以循环伏安法和交流阻抗谱对ZnS基电极的电化学特性进行了表征。结果表明,毛线球形貌的ZnS材料较大的比表面积使得以其构建的电极中电子传导速率最快,电化学特性最为优异。     

两种指示剂对碳纳米管与金纳米粒子标记DNA探针的电化学传感器的不同影响

利用层层自组装,将多壁碳纳米管(MWNTs)和金纳米粒子(GNPs)标记的DNA固定在金电极表面,结合两种不同类型的杂交指示剂构成电化学DNA传感器,用循环伏安法和差分脉冲伏安法研究了传感器的电化学行为.结果表明:这两种指示剂都能通过差分脉冲伏安法实现单碱基错配DNA的特异性检测,阳离子型杂交指示剂亚甲基蓝(MB)的最佳吸附时间为50 min,检测限为2.69×10-9 mol/L;阴离子型杂交指示剂单磺酸基蒽醌(AQMS)的最佳吸附时间为8 h,检测限为3.81×10-11 mol/L.     

氧化镍/活性炭电极的超电容性能

在制作双电层电容器基础上,采用电化学沉积法,在活性炭电极表面负载氧化镍.XRD测定表明,镍氧化物以NiO形态负载于活性炭电极上.电化学性能研究表明,氧化镍/活性炭复合电极循环伏安曲线呈矩形特征,具有良好的电容特性;其交流阻抗谱由圆弧和直线组成,电化学过程受扩散和氧化镍的赝电容行为控制;其恒电流充电曲线呈直线,电容特性显著,大电流性能良好,比容量达104.7 F/g,是活性炭电极比容量的1.35倍.