离子交换树脂法提纯维生素C磷酰化反应液

采用D301大孔弱碱阴离子交换树脂分离提纯维生素C磷酰化反应液.测定了室温下D301树脂吸附维生素C磷酸酯钠的动力学曲线和吸附等温线,考察了溶液pH值、温度、盐酸洗脱液浓度等因素对吸附的影响.最后用D301树脂对磷酰化反应液进行梯度洗脱,并用HPLC进行分析.结果表明D301树脂吸附维生素C磷酸酯钠约60 min达到平衡,Freundlich方程可以较好地描述树脂对维生素C磷酸酯钠的吸附.在室温下将磷酰化反应液调节pH至1～2后上柱吸附,依次用0.05 mol/L、0.2 mol/L、2.0 mol/L的盐酸溶液洗脱,收集0.2 mol/L盐酸洗脱液,用HPLC分析,结果其维生素C磷酸酯含量大于97%.     

树脂相分光光度法测定微量钴

在pH5．0条件下，丁二酮肟—碘化钾溶液与Co(2+)形成红棕色混配络阴离子。本文将该络阴离子吸附、富集、显色于强磁性阴离子交换树脂上，进行树脂相光度法测定。最大吸收波长为450um，摩尔吸光系数为1．4×105L·mol(-1)·cm(-1)（ε水为1．16×104L·mol(-1)·cm(-1)），Co(2+)浓度在0～0.8mg·L(-1)范围内服从比尔定律。方法用于维生素B(12)和呼和浩特地区自来水中微量钴含量的测定，结果满意。     

二甲酚橙浸渍树脂对铅和镉的吸附性能研究

用2g·L~(-1)二甲酚橙水溶液处理201×7阴离子交换树脂,制取得到二甲酚橙浸渍树脂。经过最佳条件选择,在同一水样中可以同时进行吸附、洗脱铅和镉。结果表明：二甲酚橙浸渍树脂在pH值为3～7时,对Pb~(2 )、Cd~(2 )具有较好的吸附性能。温度低有利于铅的吸附,而温度高则有利于镉的吸附。二甲酚橙树脂对Pb~(2 )和Cd~(2 )的平衡时吸附容量分别达到95和85mg·g~(-1)树脂,达到最大吸附容量平衡时仅需要50min。50mL 0．1mol·L~(-1)HCl就可以同时将铅、镉同时洗脱完全。二甲酚橙浸渍树脂吸附Pb~(2 )、Cd~(2 ),具有交换速度快、易于洗脱、富集倍数大、选择性好等优点。     

树脂吸附结合还原络合法去除盐酸中的铁离子

研究D201强碱性阴离子交换树脂（Cl型）吸附结合还原络合法进行盐酸除铁离子精制的过程,最佳试验条件为：采用D201强碱性阴离子交换树脂（Cl型）,还原剂硫代硫酸钠加入量1%（相对树脂质量,下同）,螯合剂EDTA加入量0.5%;在该条件下进行盐酸除铁离子精制,铁离子质量浓度降至0.1 mg/L以下。     

F-2型树脂吸附铼的研究

研究了F-2型阴离子交换树脂在弱酸体系中吸附、解吸铼的性能和机理.结果表明,H+浓度在0～0.4mol/L时对铼的吸附有利.树脂对铼的静态和动态的饱和吸附容量分别为每克干树脂169.31mg和175.43mg.淋洗剂选用2mol/L硫氰酸铵,流速2ml/min,回收率大于92%.     

离子交换法从硫酸锰溶液中吸附氯的实验研究

选用大孔阴离子树脂对硫酸锰溶液中的氯离子进行了静态和动态的吸附实验研究,结果表明,在pH=6.5～7.0,氯离子含量为1.53 g/L的条件下,树脂对Cl-有良好的吸附性能,氯的交换容量为20.3 mg/g湿树脂,吸附的氯离子可用0.5 mol/L的稀硫酸解吸,解吸率可达97.4%。     

一种新型吸附剂处理废水中镉离子的研究

以聚合氯化铝改性盐酸酸化的凹凸棒土,制备得到一种新型吸附剂APAC,用红外光谱进行了结构确认。通过实验考察了APAC对模拟废水中镉离子的吸附性能,结果表明,在废水中镉离子量一定条件下,以浓度为1mol/L盐酸酸化凹土,m(酸化凹土)∶m(聚合氯化铝)=1∶1,APAC加入量为0.5g及吸附时间为2h时,镉离子的去除率高达95.8%。     

化学修饰碳糊电极对环境水样中微量铅、镉离子的连续电化学测定

报道了用8-羟基喹啉作碳糊电极的修饰剂,测定环境体系中微量铅、镉离子的电化学方法.该电极在KNO3(pH=4.0)中,用吸附溶出伏安法测定Pb2+、Cd2+,在-0.56V(vs,SCE)和-0.84V处有灵敏溶出峰,峰电流与铅的浓度在(3.0×10-8～4.5×10-6)mol/L的范围内呈良好的线性关系,与镉的浓度在(4.0×10-8～3.5×10-6)mol/L的范围内呈良好的线性关系,该方法用于水样中铅、镉的测定,检出限为3.0×10-9mol/L(Pb2+)和5.0×10-9mol/L(Cd2+).     

正交实验优化离子交换树脂静态吸附盐酸育亨宾的工艺研究

分别用732型阳离子交换树脂与717阴离子交换树脂对盐酸育亨宾进行静态吸附与解吸,研究乙醇浓度、吸附温度、pH值对盐酸育亨宾吸附、解吸的影响。结果表明,732型阳离子交换树脂对盐酸育亨宾具有较好的吸附、解吸能力,最佳吸附条件为:乙醇浓度40%,温度40℃,pH=7,吸附量1 132.785 4μg/g;最佳解吸条件为:解吸温度30℃,乙醇浓度70%,pH=1,解吸量718.239 8μg/g,解吸率为89.49%。     

硫酸中镉的吸附催化波研究和应用

研究了在HCI—V.C—KI—PVA混合底液体系中镉的络合吸附波的性质。对该体系进行了最佳条件选择,确定了镉的吸附催化波电位为-0.65V(vs.SCE),镉离子浓度在8.897×10~(-8)～1.335×10~(-5)mol/L范围内与波峰电流呈线性关系,测定下限4.448×10~(-8)mol/L,并对极谱机理进行了讨论。     

The electrocrystallisation of cadmium sulphide films of cadmium

The growth of anodic CdS films on polycrystalline Cd takes place in two stages. Initially a barrier film grows to a thickness of about 5nm by high-field ion migration. This film contains as many as 10²⁵ donors in m^?3. When an electrode potential exceeds a critical value, the second stage of film growth begins, and a porous or polycrystalline. CdS layer forms over the original barrier layer. This type of film can thicken to 500 nm or more by a diffusion-controlled process. The kinetics and mechanism of both kinds of film growth are discussed.     

碳酸镉转化制备氢氧化镉及产物光催化降解性

用碳酸钠溶液直接混合硫酸镉溶液制备了沉淀碳酸镉,再以沉淀碳酸镉为基体,氢氧化钠溶液为转化剂,通过阴离子交换制备出氢氧化镉纳米材料。采用X射线衍射仪（XRD）和场发射扫描电子显微镜（FESEM）对沉淀碳酸镉和转化产物的结构和形貌进行了表征。结果表明,沉淀碳酸镉的结构遭到破坏,转化完全所得到的氢氧化镉的形貌完全不同于沉淀碳酸镉,为片状组装的不规则球体。紫外光照射下光催化降解罗丹明B染料测试表明,转化产物比沉淀碳酸镉具有更好的光催化降解性能,转化时间不同的产物表现出不同的降解效率。当20 mg的转化产物分散到50 mL 8 mg/L的罗丹明B染料中,在黑暗环境中磁力搅拌吸附120 min达吸附平衡,开启300 W紫外汞灯后,效率最高的转化产物可在180 min内将染料完全降解。     

Electrolytic production of metallic cadmium and cadmium–sodium alloys in alkali melts

Reprocessing of cadmium-containing wastes and used storage batteries produces cadmium oxide. Electrowinning of the metal from an alkali melt is proposed for processing of CdO and production of metallic cadmium or cadmium–sodium alloys. The design of a laboratory electrolyzer is discussed. Technological parameters of the electrolysis process are determined. Applied and engineering aspects of the electrowinning of cadmium and cadmium–sodium alloys are considered. Conditions of the electrolytic production of cadmium are optimized. Specific features of the electrochemical production of cadmium–sodium alloys are analyzed. Electrowinning of cadmium from an acid or chloride solution is considered. The comparison of the electrolysis of aqueous solutions and alkali melts is in favor of the latter.     

Mechanical and nuclear shielding properties of sodium cadmium borate glasses: Impact of cadmium oxide additive

In this study, highly effective radiation shielding glass materials with different amount of CdO additive were investigated in terms of nuclear shielding performance. Moreover, mechanical properties have been determined. The μ_m values were computed using XCOM and XMuDat program. The gamma and neutron shielding parameters such as μ_m, HVL, Z_eff, EBF, EABF, SAFE, b_co, b_ico, σ_co and σ_abs are calculated to understand the radiation shielding performances of investigated glasses. The results show that μ_m, Z_eff and σ_abs values increase as the CdO content increases. The S7 sample has the lowest HVL, MFP, EBF, EABF, SAFE, b_co, b_ico and σ_co values. Therefore, S7 glass sample (70 mol% of CdO) which has also the highest number of bonds per unit volume can be considered as a superior material for radiation shielding applications. The outcomes of this study can be very useful for future applications of investigated glass materials in medical and industrial radiation fields.     

Synthesis of cadmium(II) hydroxide, cadmium(II) carbonate and cadmium(II) oxide nanoparticles; investigation of intermediate products

Sonochemical and hydrothermal routes have been used in different conditions for preparation of CdCO₃ and Cd(OH)₂ nanoparticles at air and inert atmospheres, respectively. The CdO nanoparticles were obtained by heating of CdCO₃ and Cd(OH)₂ nanoparticles at 400 °C. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) microscopy have been used to characterize the nanoparticles. The XRD results of intermediate products showed that the origin of CdCO₃ is CO₂ from air atmosphere.     

Selective precipitation of cadmium from nickel cadmium sulphate solutions using sodium decanoate

Each year in France, about 1300 tons of spent Ni–Cd batteries are collected. Their treatment consists of crushing, physical separation, acidic leaching of electrode materials, separation and recovery of metals leached with different processes. In this work, the selective precipitation of cadmium in synthetic Ni–Cd mixtures was investigated using sodium decanoate as precipitant. A factorial design of experiments was used to improve the separation using variables such as cadmium concentration, pH, molar ratio between decanoate and cadmium, time of addition of precipitant and rest time of the solution. In the best conditions defined by a 2⁵⁻² fractional factorial design, starting with concentrations of 0.1 mol L⁻¹ of nickel (5.9 g L⁻¹) and 0.05–0.15 mol L⁻¹ of cadmium (5.6–16.8 g L⁻¹) it is possible to recover in only one stage about 99% of cadmium without precipitating more than 5% of nickel. The results of the separation are on one side a pure solution of nickel at 2.39 × 10⁻² mol L⁻¹ (1.4 g L⁻¹) containing 3.44 × 10⁻⁴ mol L⁻¹ of cadmium (about 40 mg L⁻¹) and on the other side a precipitate of cadmium decanoate with a cadmium content equal to 23.6 wt% and nickel content lower than 0.8 wt%. These results demonstrated the viability of this separation.     

改性淀粉在低浓度含镉废水处理中的应用实验

对淀粉（St）接枝共聚丙烯酰胺（AM）并与巯基乙酸（MCAA）反应进行了研究,将得到的产物用于低浓度含镉废水处理取得了较好的效果。研究了淀粉与丙烯酰胺配比不同对St-AM接枝率和接枝效率的影响并对巯基化后得到的产物St-AM-MCAA的巯基含量进行了测定。对低浓度（0.4mg/L）含镉废水的处理研究发现：含镉废水在pH=8,添加量为50mg时镉去除率可达89.7%;St-AM-MCAA较St-AM产物能提高Cd2+去除率10%以上。     

Contribution of dissolved cadmium to the viscosity of its solutions in molten cadmium chloride, bromide and iodide

Viscosity coefficient of molten Cd---CdX₂ (X---Cl, Br and I) systems as a function of the mole fraction of dissolved cadmium have been measured at temperatures between 903 K and 1.2 T^s_f, where T^s_f is the melting point of the particular salt solvent. The influence of dissolved metal on the viscosities of these salts has been correlated with the free volumes of the salt solvent. The calculated radii of the supposed flow units were found to be closer to the radius of Cd⁰ than that of Cd²⁺₂.According to the Cohen and Turnbull theory the temperature dependences of electrical conductivity and of viscosity of the molten cadmium halides lead to the radii of the electrical and viscosity transport units in these salts close to those of the corresponding anions.     

Electrospinning preparation and characterization of cadmium oxide nanofibers

Using a facile synthesis route, cadmium oxide (CdO) nanofibers in the diameter range of 50–60 nm have been prepared employing the electrospinning technique followed by a single-step calcination from the aqueous solution of polyvinyl alcohol (PVA) and cadmium acetate dihydrate. Electron microscopy (EM) and the Brunauer–Emmett–Teller (BET) technique were employed to characterize the as-spun nanofibers as well as the calcined product. The specific surface area of the product was calculated to be 42.6711 m² g⁻¹. Infrared (IR) absorbance spectroscopy and X-ray powder diffractometery were conducted on the samples to study their chemical composition as well as their crystallographic structure. The study on the optical properties based on the photoluminescence (PL) spectrum demonstrated that the emission peaks of CdO nanofibers are centered at 493 and 528 nm. The direct bandgap of the CdO nanofibers was determined to be 2.51 eV.