湖北白果坪磷矿镉地球化学特征及研究意义

通过对白果坪磷矿床中镉地球化学特征的研究,探讨了对磷块岩矿床中镉的表生地球化学作用过程研究的意义.白果坪磷矿风化磷矿中的镉含量较原生磷矿镉含量高近一倍,表明在地表氧化环境下,镉元素在酸性水溶液的作用下被氧化淋滤发生了明显迁移.镉在磷块岩中的赋存状态为类质同象和吸附态,在风化磷矿石中以吸附态为主.研究镉元素在表生风化作用下的活化-迁移-沉淀富集机理可以为防治磷矿山开采中可能产生的镉污染提供对策.     

铁基凝胶材料对镉砷复合污染土壤的稳定化效果研究

以镉砷复合污染土壤为研究对象，采用铁盐与海藻酸钠(SA)为原料，通过碱性-交联法制备了一类铁基凝胶稳定材料，考察了不同铁盐类型和铁盐掺入量制备的凝胶材料对污染土壤中Cd和As的同步稳定效果。结果表明：以FeCl₃作为铁盐原料，m(FeCl₃)∶m(SA)=0.88∶1.00条件下制备的铁基凝胶材料F1(1)对Cd和As的同步稳定效果最佳。当铁基凝胶材料F1(1)添加质量比为5%时，土壤中Cd和As的稳定效率分别为87.76%和93.42%,镉砷同步稳定权衡值T显著降低至1.45。稳定15 d后，土壤中Cd的稳定效率降为82.94%,As的稳定效率上升至97.38%,镉砷同步稳定权衡值T为1.55。     

原子吸收光谱法测定镀金溶液中的镉

1 前言我厂三元镀金溶液中含镉量很低,不宜于采用化学法测定,经大量试验,确定选用原子吸收光谱分析法,测定三元镀金溶液中镉的含量.现将实验工作报导如下2 实验部分2.1 试剂和仪器(1)镉标准溶液:称取纯镉(99.99%)0.1000g以少量盐酸(1+1)加热溶解,冷却后移入250mL量瓶中,以水稀释至刻度,摇匀.溶液     

石墨炉原子吸收法测定不锈钢食具镉镉元素迁移量的不确定度评估

石墨炉原子吸收法测定不锈钢食具镉元素迁移量的不确定度,依据测量不确定度的评定原理和方法,对GB/T 5009.81-2003中不锈钢食具乙酸浸泡液的镉迁移量进行不确定度来源分析,量化不确定度分量,最后得出扩展不确定度。当测量结果为0.000 30 mg/dm2,合成标准不确定度为0.000 013 mg/dm2,扩展不确定度为0.000 03 mg/dm2(包含因子k=2)。     

摩擦行为对日用陶瓷中铅镉溶出量影响的研究

考察摩擦行为对日用陶瓷中铅镉溶出量的影响,分别采用GB31604.34-2016 《食品安全国家标准食品接触材料及制品铅的测定和迁移量的测定》和GB 31604.24-2016《食品安全国家标准食品接触材料及制品镉迁移量的测定》规定的方法,检测市售新的日用陶瓷器皿和长期使用过的日用陶瓷器皿中铅镉溶出量的情况。溶出量试验条件分别为4%(体积分数)乙酸溶液于22±2℃温度下,浸泡24h±20min,研究动态摩擦行为对市售日用陶瓷器皿中铅镉溶出量的影响。结果表明,长期使用摩擦后日用陶瓷第一次浸泡,铅镉溶出量明显高于新购买的日用陶瓷第一次浸泡。并实验不同摩擦次数对铅镉溶出量的影响,结果表明,摩擦行为促进日用陶瓷中铅镉溶出量,当动态摩擦到达7次后,铅镉溶出量基本到达平衡。     

2—乙基己基膦酸单（2—乙基己基）酯萃取分离锌镉

1.前言锌镉在自然界中多以MS形式存在,镉主要存在于锌的各类矿石中。在火法冶炼中,两种金属同时被还原,不易分离。本文采用2—乙基己基膦酸单(2—乙基己基)酯(简称P507)萃取分离锌镉—湿法冶金,选择出适宜萃取及分离的各种有关条件,为     

硒镉红色铁封玻璃的研制

作者以R_2O-RO-B_2O_3-SiO_2系统为基础玻璃,用硫化镉(CdS)和硒粉(Se)为着色剂,制备出具有与铁封接所需要的热膨胀系数和其他各种性能的硒镉红色铁封玻璃.     

镀镉法

简史镀镉用的氰化溶液配方法,虽早于1849年发表,但镀镉在商业上的应用,却是1915年以后的事。大概在1919年,幽弟(Marvin J.Udy)在这方面的工作,给商业性的镀镉以最早的推动力。他所用的镀镉溶液是由氢氧化镉配成的,其成份包括镉氰化钠(Sodium (?)admicyanide)及氢氧化钠,但没有游离的氰化钠成份存在。幽弟并认定在高碳钢上所镀的镉层,必须经过烘焙手续,以除去镀层中由于氢素所引起的脆性。1922年亨夫里氏(C.H.Humphries)对于氰化镉溶液镀镉用的加亮剂(Brightening Agent)作了最早的介绍,那是一种含有羊毛蛋白质或其他蛋白质的苛性溶液。1926年,霍夫(C.M.Hoff)又发表了关于镀镉溶液与镉层性质关系的论文,这一来就奠定了镀镉事业的稳固基础。此后的发展大都沿着下述的四条路线:(1)对于氰化物镀液用的新加亮剂有所发现,此新加亮剂可使镉层得到比较宽广的光亮范围,而今日所用的浸亮法(Bright dip),对于多凹面的物件,更能增加镉层的均匀亮光。     

含有植物纤维或玉米淀粉的食品接触产品质量安全风险研究

研究市售的含有植物纤维或玉米淀粉的食品接触产品质量状况并对其安全性进行初步评价。参考标准要求并结合可能存在的质量安全隐患,从傅里叶变换红外(FTIR)材质分析、总迁移量、重金属(以Pb计)、脱色试验、五氯苯酚特定迁移量及砷、镉、铬、铅含量等维度对含有植物纤维或玉米淀粉的食品接触产品进行研究。35批次样品中有2批次塑料主体材质为密胺,2批次塑料主体材质为聚乳酸,31批次塑料主体材质均为聚丙烯;35批次样品的重金属(以Pb计)、脱色试验、五氯苯酚特定迁移量等项目均符合所参照标准的要求;35批次样品均检出至少含2种重金属,有4批次一次性淀粉餐具总迁移量超标。从检验结果可知,市面上销售的含有植物纤维或玉米淀粉的食品接触产品存在总迁移量超标及样品含重金属的情况,说明市场上该类产品确实存在一定的潜在风险。     

2-羟基-5-氟-3-磺酸基苯基重氮氨基偶氮苯的合成

合成了2-羟基-5-氯-3-磺酸基苯基重氮氨基偶氮笨,并研究了它与镉(Ⅱ)的显色反应.实验表明,在Triton X-100的存在下,pH11.2的Na2B4Or-NaOH缓冲介质中,镉(Ⅱ)与之形成1:3的红色配合物,在528 nm处有最大吸收.表观摩尔吸光系数为2.46×105L·mol-1·cm-1,镉(Ⅱ)在0～20μg/25 mL范围内遵守比耳定律.方法应用于废水中微量镉的测定,结果令人满意.     

Facilitated Transport of Cd(II) Through a Supported Liquid Membrane with Aliquat 336 as a Carrier

Selective removal of cadmium from wastewaters is very important, because cadmium is toxic for the environment and for human health. This work is a comprehensive study on the selective removal of Cd(II) from aqueous solutions by using a co-current flow flat sheet supported liquid membrane system. 4.4 × 10^?4 M Cd(II) concentration was used as a feed solution in the experiments. Toluene containing Aliquat 336 was used as the membrane liquid in the membrane system. Parameters such as the properties of feed and stripping solutions, carrier concentration, and flow rate, which have roles in transport of Cd(II) ions, were optimized. The efficiency of the system is expressed in terms of permeability and flux values, and transport efficiency. The optimum process conditions for the Cd(II) transport are experimentally found as follows: The feed solution as 2 M HCl, the carrier concentration as 0.1 M Aliquat 336, the stripping solution as 0.06 M EDTA, and the flow rates for the feed and stripping solutions as 50 mL/min and 80 mL/min, respectively. Under these conditions, the Cd(II) transport efficiency is found to be 82%.     

POSSIBILITY OF CONCENTRATION POLARIZATION OCCURRING INSIDE THE MEMBRANE DURING STEADY STATE PERVAPORATION

Mathematical equations are derived for describing the pervaporation transport of pure penetrant through polymeric membranes by assuming the chemical potential gradient as the driving force for the flow of penetrant. An imaginary phase (liquid or vapor) is assumed to be present and is in thermodynamic equilibrium with the membrane phase for deriving these equations. The mathematical equations obtained are similar to those derived by Okada and Matsuura (1991) using the pore-flow model. The possibility of concentration polarization occurring inside the membrane is predicted based on the analysis of binary mixture pervaporation. Experimental profiles of binary penetrant concentration in the membrane are established and these profiles substantiate the prediction of concentration polarization occurring inside the membrane. Pervaporation and sorption data from liquid and vapor phase at 25° C are reported for the acetic acid-water-polyamide system.     

组合液膜分离镉锌的动力学分析

采用膜相和反萃相分别为三正辛胺的煤油溶液和醋酸胺的水溶液的组合液膜体系,研究了氯化物料液中镉、锌离子的分离.结果发现,传质过程主要由料液相侧水扩散层和膜相的扩散过程控制;迁移20 h后,镉离子迁移率可达98.3%,锌离子迁移率只有2%,分离系数为49.2.组合液膜能很好地分离镉、锌.流失到料液相和反萃相的载体浓度测试表明,组合液膜中,双固体膜能阻止膜相中载体的流失,提高膜的稳定性,延长膜寿命.改变三正辛胺浓度,对镉离子传输的动力学过程进行了分析,建立了镉离子传输的动力学方程.     

THE STUDY ON THE MASS TRANSFER MECHANISM OF EUROPIUM ION THROUGH LIQUID SURFACTANT MEMBRANES

The transfer of trivalent europium ion in a liquid surfactant membrane system is investigated in order toclarify the characteristics of liquid membrane separation process and the availability of this technique forrecovering trivalent lanthanides and actinides.A layered structure model for the emulsion globule is sug-gested.The equations describing the relationship among the effective membrane thickness,the time andother factors are derived and verified experimentally.Results show that under certain conditions the decreas-ing concentration of europium ion in the external phase is proportional to the square root of the time,the acidity of the internal phase and the carrier concentration in the membrane phase.The membrane phase consists of kerosene(solvent),Span-80(surfactant)and di-(2-ethylhexyl) phosphoricacid(HDEHP,carrier).The internal phase is dilute nitric acid and the external phase is aqueous solu-tion containing Eu(NO_3)_3.The mass transfer rate of europium in this system is high and the recovery ofeuropium may be more than 99%.     

Analytical study of type-1 facilitated transport through liquid surfactant membrane

In the present study, a mass transfer model for Type-1 facilitated transport in liquid surfactant membrane is developed by taking into consideration a size distribution of emulsion drops, and analytical solution of the model equations has been presented. The model takes into account the continuous phase and outer liquid membrane phase resistances along with diffusion through composite emulsion drop. Effort has been made to highlight the effect of the various system parameters on the extraction rate including computation of reaction front position. The results of this work are found to be in good agreement with the published experimental results on batch extraction of phenol using NaOH as internal reagent. The model would thus provide an insight of the separation mechanism involved in the mass transfer processes in this type of system.     

Studies on Carbonate Ion Transport through Supported Liquid Membrane Using Primene JMT and Tributyl Phosphate

Abstract

A supported liquid membrane system consisting of source, receiving and membrane phases, in which mixed extractants were used in the membrane phase, was explored for the carbonate ion transport from source to receiving through membrane phase. Primary amine Primene JMT and TBP were used as extractants (carriers) in liquid membrane phase. Different experimental variables such as concentration of carbonate ion, carriers, alkali and hydrogen peroxide, stirring speed, etc have been investigated. Primary amine Primene JMT and TBP mixed carriers show the synergistic effect for the transport of carbonate ions through supported liquid membrane system. The stability of the supported liquid membrane system has been explored for 50 h. The pre-concentration of carbonate ions from dilute solutions were also demonstrated. The effect of different alkalis on the permeability coefficient of transport of carbonate ions through supported liquid membrane system has been investigated. The primary amine in combination with TBP shows more effective for the transport of carbonate ions through supported liquid membrane system in comparison with that of secondary and tertiary amines.     

Analysis of Extraction of Cu(II) by Strip Dispersion Hybrid Liquid Membrane (SDHLM) using PMBP as Carrier

A liquid membrane system, denoted a strip dispersion hybrid liquid membrane (SDHLM) containing 1‐phenyl‐3‐methyl‐4‐benzoyl‐pyrazolone –5 as carrier in xylene, was reported for the transport and separation of Cu(II) from Zn (II) ions. The effects of various factors on the transport of copper(II) ions through SDHLM were systematically investigated by orthogonal tests. The optimum transport conditions of copper ions were summarized. In the overall mass transfer process the mass transfer resistance due to the aqueous boundary layer diffusion and diffusion in the microporous membrane is dominant. The accumulation of the Cu(II)‐carrier coordination compound in the membrane shows that the transfer in SDHLM possesses the characteristic of nonequlibrium mass transfer in this study. The rheologic experiments verified that the organic phase in the SDHLM system was the non‐Newtonian fluid and the organic phase after transport of 6 hr was a system of thixotropy in our experimental conditions. The lag ring experiments proved that the thixotropy of the organic phase in the SDHLM system was relevant to the composition of the membrane. In the experimental comparison of two types of liquid membrane, SDHLM has superiority over SLM in respect of transport flux, permeability coefficient, recovery percentage or concentration of solute in the stripping solution, efficiency of uphill transport, loss of membrane solution, and the separation efficiency of the membrane.     

Facilitated Transport through a Liquid Surfactant Membrane with Continuous Phase Resistance: Role of Drop-Size Distribution

Abstract

An advancing reaction front model with drop-size distribution has been proposed for the case of facilitated transport through a liquid surfactant membrane. The model takes into account the continuous phase and outer liquid membrane phase resistances along with diffusion through a composite emulsion drop. The computed results are found to be in excellent agreement with the experimental data of Ho et al. The outer liquid membrane phase resistance seems to be an important parameter in controlling the overall extraction rate. Analytical solutions to model equations for uniform drop size are also presented in this study. The model is also capable of predicting the effect of various parameters on the overall extraction rate for the limiting cases of inverse Biot modulus tending to zero and infinity.     

用含两亲高分子的乳液膜体系迁移痕量Cd2+

将两亲高分子聚 (丙烯酸—甲基丙烯酸十二酯 )作为膜稳定剂加到由Span 80、煤油、液体石蜡和水等组成的W /O型乳液膜中 ,研究了此液膜对痕量Cd2 + 的迁移作用。结果表明 ,由于两亲高分子的空间稳定作用而导致乳液膜对Cd2 + 具有较高的迁移效率     

用乳状液型液膜提取铕的传质机理研究

本文研究了用乳状液型液膜提取稀土元素铕的工艺条件,考查了不同因素对铕的传质速率的影响.实验结果表明,以二(2-乙基己基)磷酸为载体,硝酸为解络剂的乳状液型液膜对铕的迁移效果很好.本文重点探讨了该液膜体系的传质机理,推导出本体系的传质通量式,并用实验数据进行了验证,取得了较好的一致性.