N_(235)对废水中艳红B络合萃取的实验研究

在室温下,以三烷基叔胺(N235)作为络合剂,分别以煤油、磺化煤油和正辛醇作为稀释剂对艳红B溶液进行萃取实验。结果表明,三种稀释剂对艳红B萃取效果为正辛醇磺化煤油煤油。在最佳萃取条件下:络合剂与稀释剂体积比为3∶1,萃取剂与艳红B溶液体积比为1∶5,溶液初始pH=2.0时,N_(235)+正辛醇的萃取体系单次萃取率可达98.7%。在此基础上用NaOH溶液对其萃取相进行反萃,单次反萃率达到94.5%。反萃后得到的萃取剂可循环使用,回收后的萃取剂对模拟染料废水艳红B溶液COD的去除效果与新鲜萃取剂相当。     

D2EHPA萃取回收Cr(Ⅲ)的研究

以回收废水中Cr(Ⅲ)为目的,选择2-乙基己基磷酸(D2EHPA)为萃取剂,煤油为稀释剂,进行了萃取回收Cr(Ⅲ)的实验研究.考察了皂化剂种类、溶液pH值、助溶剂种类、萃取剂浓度等因素对于萃取平衡影响以及三种无机酸、两种有机酸对于负载Cr(Ⅲ)的D2EHPA反萃效果的影响.结果表明,pH值是影响D2EHPA/煤油萃取Cr(Ⅲ)的重要因素, 在pH＜2时,D2EHPA几乎不萃取Cr(Ⅲ),通过萃取剂的皂化,提高水相pH值,可以实现D2EHPA萃取Cr(Ⅲ).随平衡水相pH值的升高,D2EHPA显示出良好的萃取效果.NaOH溶液作为皂化剂比氨水的分相效果好.加入助溶剂后萃取效率提高,其中10%～20%正辛醇是适宜的助溶剂选择.D2EHPA/正辛醇/煤油萃取Cr(Ⅲ)后立即用无机酸或有机酸反萃,其中硫酸、盐酸或草酸的反萃率能够达到90%以上.     

提高钛白废酸提钪萃取选择性的研究

研究旨在选择合适的助萃剂LH,提高二（2-乙基己基）磷酸（P204）-磷酸三丁酯（TBP）-磺化煤油体系对钛白废酸提钪的选择性,提高钪钛分离系数和钪铁分离系数。研究采用的工艺为二次萃取富集、二次反萃成钪、化学精制提纯钪。通过正交试验确定最佳萃取工艺条件：萃取剂最佳配比V（P204）∶V（TBP）∶V（磺化煤油）=1.3∶0.7∶10,一次萃取相比为V（O）∶V（A）=1∶21,不加助萃剂二次萃取相比为V（O）∶V（A）=1∶5,加助萃剂时其加量为水相体积的1.7%,此时钪钛分离系数达到124 812,钪铁分离系数达到8 202。     

醋酸清洁生产工艺的研究

采用络合萃取法处理稀醋酸废水 ,使用填料萃取塔和反萃技术分离有机酸 ,在醋酸生产工艺中实现清洁生产。针对萃取剂的选择、填料萃取塔的操作特性和初步的反萃实验做了研究。使用三正辛胺 (TOA)和异辛醇为助溶剂 ,煤油为稀释剂(质量比为 3∶5∶2 ) ,在 4∶1的水相 /有机相相比下 ,4级错流萃取实验和模拟 3级逆流萃取后水相中残余醋酸的质量分数均降至6× 1 0 - 5,达到回用要求     

络合萃取法处理高浓度H酸废水

采用络合萃取法处理高浓度H酸废水,考察了萃取体系、萃取时间、萃取级数、萃取剂体积分数、相比(A/O)、油碱比对COD的去除效果的影响。最佳体系为:三辛胺为络合剂,煤油为稀释剂,正辛醇为助溶剂。以三辛胺/煤油/正辛醇体系进行萃取实验,得到最优工艺参数为:V(三辛胺)/V(煤油)=1/4,相比(A/O)=5/1,pH=2.3,萃取时间为30 min;当H酸初始COD为35 000 mg/L时,经两级错流萃取后COD去除率可达到83.4%。采用12.5%的Na OH溶液对萃取相进行反萃取,可回收并循环利用萃取剂。实验结果表明:络合萃取工艺处理H酸生产废水效果显著,达到了预处理的目的,有利于实现工业化生产。     

三辛胺萃取草酸的机理

选择草酸稀溶液为萃取对象 ,采用三辛胺 (TOA)为络合剂 ,正辛醇为稀释剂 ,开展了TOA萃取草酸的机理研究 .以红外谱图为分析手段 ,通过测定络合剂及被萃溶质的浓度对萃合物组成的影响 ,得到其萃合物以 1∶1和 1∶2 (酸 :碱 )两种形式存在于有机相中 ;并通过萃取平衡实验 ,获得了TOA萃取草酸的平衡特性 ,进一步验证了萃合物组成 .以此为基础建立了草酸与TOA两种萃合比情况下的数学模型 ,拟合求得了K₁₁及K₁₂ ,其中 1∶2萃合物的化学萃取平衡常数远远小于 1∶1的相应值     

络合萃取法处理6-硝基间甲酚废水

采用络合萃取法处理6-硝基间甲酚废水,一次萃取率达到99.9%,最佳的萃取条件为V(络合剂)∶V(稀释剂)=1∶2,萃取油水体积比为1∶2,溶液pH值低于3。萃取剂可经过反萃再生其效率不变。     

络合萃取法处理高浓度苯酚废水

以三辛胺为络合剂,正辛醇为稀释剂,通过络合萃取-反萃取的方式,回收高浓度苯酚废水中的苯酚。利用响应曲面法研究了络合剂浓度、油水比、废水的p H值对萃取效率的影响。结果表明:以体积浓度为33.8%的三辛胺为络合剂,正辛醇为稀释剂,油水比为0.28,p H值为4.69,苯酚络合萃取率可以达到99.82%,此时萃余水相中苯酚的浓度为36 mg/L,完全可以实现苯酚的回收再利用。     

络合萃取法从稀溶液中提取草酸

为深入认识二元酸的络合萃取平衡特性及萃取机理,以三辛胺（TOA）为络合剂,正辛醇为助溶剂,煤油为稀释剂,草酸为被萃溶质,进行了混合溶剂的萃取平衡实验研究,测定了络合剂的浓度、稀释剂的组成等因素对萃取平衡分配系数的影响,并对TOA萃取草酸的机理进行了探讨。实验结果表明,随TOA浓度的增大,萃取平衡分配系数呈增大趋势;随溶质初始浓度的增大,有机相的溶质浓度向饱和萃取量接近;饱和萃取量随络合剂浓度的增大而增大;稀释剂对萃取平衡的影响与TOA浓度有关,TOA浓度较小时,煤油的加入使萃取平衡分配系数减上,TOA浓度较大时,煤油的加入对萃取平衡影响较小。     

三辛胺萃取马来酸(Ⅰ) 平衡特性

以三辛胺 (TOA)为萃取剂 ,正辛醇、甲基异丁基酮 (MIBK)、正己烷和氯仿为稀释剂开展了萃取平衡特性及负载溶剂红外光谱结构分析的实验研究 .结果表明 ,稀释剂对萃取的影响与马来酸和萃取剂的浓度有关 .对于 4种稀释剂体系 ,当平衡水相酸浓度较低时 ,萃取马来酸的次序为质子化稀释剂大于一般极性的稀释剂 ;反之 ,萃取马来酸的次序为 :MIBK >正辛醇 >正己烷 >氯仿 .TOA在平衡水相酸浓度较低时能提供较大的萃取分配系数 ,萃取剂化学计量饱和后存在“过载”现象 ,大小次序为MIBK >正辛醇 >正己烷 >氯仿 .负载溶剂的红外光谱分析表明 ,马来酸作为二元有机酸 ,与TOA只存在一盐的萃合物形式 ,有机相中不存在马来酸的聚集体 ,可以认为只有 1∶1型酸胺萃合物     

Electrochemical regeneration of sodium thiocyanate

All-Russian Scientific-Research Institute of Polymer Fibres, Mytishchi. Translated from Khimicheskie Volokna, No. 2, pp. 47–49, March–April, 1995.     

Cathodic reduction of phenacyl thiocyanate

The cathodic reduction of phenacyl thiocyanate in aprotic medium leads to an enolate, which acts as nucleophile in addition or substitution reactions as well as electrogenerated base. The products of these reactions were isolated and identified as 2,4-diphenylthiophene, 1,4-diphenyl-1,4-butanedione, 1,5-diphenyl-3-benzoyl-1,5-pentanedione, trans-1,2,3-tribenzoyl cyclopropane and acetophenone.     

A preparation of lead thiocyanate

Summary A new and improved method for the preparation of a pure and stable lead thiocyanate in practically theoretical yield has been described. A comprehensive investigation of other published methods has been reported and preparations of lead thiocyanate made by these methods have been compared with the improved compound and various commercial products. All of the products were assayed for purity on the basis of their chemical analyses and tests were made of their capacity for saturating double bonds in cottonseed, peanut, and soybean oils. The lead thiocyanate prepared according to the recommended procedure was found superior to all the other products in stability, purity, and ability to produce dependable and reproducible thiocyanogen values. It has been demonstrated that the ratio of lead ions to thiocyanogen ions and the order of addition of these ions to each other are of major importance in the preparation of pure lead thiocyanate. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U.S. Department of Agriculture.     

Electrochemical oxidation of thiocyanate in a two-phase electrolyte

A two phase electrolysis method has been developed for preparation of thiocyanating reagent. The electrolyses were carried out using graphite electrodes using a two phase electrolytic medium made up of an aqueous solution of ammonium thiocyanate in 0.25m H₂SO₄ and a nonaqueous solvent. The effect of experimental parameters, such as temperature and duration of electrolysis, nature of the nonaqueous solvent and volume fraction of the nonaqueous phase, on the process current efficiency were studied. The voltammetric studies in the nonaqueous phase established that trithiocyanate, (SCN)₃ ^–1, was produced in the aqueous phase and was subsequently extracted into the non-aqueous phase.     

分光光度法测定腈纶中微量硫氰酸根

在pH为1～1.5的硝酸酸性条件下,硫氰酸根和铁(Ⅲ)反应形成红色络合物,在体系中加入2-4mL稳定剂(Triton-100),提高了络合物的稳定性。利用分光光度法可有效测定腈纶中硫氰酸钠含量。应用表明,该方法稳定实用,其回收率在98%-104%。     

硫氰酸红霉素生产废水处理工程实例

某污水处理工程针对硫氰酸红霉素生产废水成分复杂、含量高、生物降解性差的特点,采用"催化微电解、水解酸化、厌氧膨胀颗粒污泥床(EGSB)、循环活性污泥处理系统(CASS)、Fenton氧化、曝气生物滤池(BAF)"的工艺路线对其进行处理。调试运行结果表明,经该组合工艺处理后,出水各项指标均低于《山东省南水北调沿线水污染物综合排放标准》(DB 37/599—2006)的要求。该工艺可满足大规模硫氰酸红霉素生产废水处理需要。     

Gold dissolution in acidic thiourea and thiocyanate solutions

Gold dissolution in acidic solutions containing thiourea (Tu) and thiocyanate was studied using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and surface enhanced Raman spectroscopy (SERS). A synergistic response found in that mixed ligand system promoted a higher dissolution rate than either lixiviant alone. The passivation of gold occurs in a Tu only solution, but when thiocyanate is mixed with Tu, passivation is significantly alleviated. The dissolution rate of gold in the mixed lixiviant system increases with increasing Tu and thiocyanate concentration. Results from LSV and EIS indicate that gold dissolution is controlled by a combination of charge transfer and diffusion in the mixed lixiviant system. The optimum concentration for Tu and thiocyanate is about 5 mM and 0.05 M, respectively for the rate of gold dissolution. SERS results suggest a possible formation of a mixed ligand complex involving the interaction of Au(Tu)₂⁺ and SCN⁻. Further study is necessary to identify the mixed ligand complex.