用4种溶液对金、银和铂进行溶解的研究

在25℃下，用4种溶液对金，银和铂进行溶解，在金的溶解中，用王水和碘／碘化钠（I^-3/I^-）溶液对金有较快的溶解速度，漂白粉－HCl-NaCl溶液和Fe2(SO4)3-H2SO4/硫脲溶液对金的溶解速度较慢，在银的溶解中，只有Fe2(SO4)3-H2SO4／硫脲溶液对银有明显的溶解作用，其余3种溶液只能缓慢溶解极少量银，4种溶液对铂均无明显的溶解作用。     

添加剂作用下铁粉还原酸性硫 脲浸金液中的金

酸性硫脲浸金液由于H+、Fe3+和Cu2+等杂质离子的存在，直接采用金属置换法回收金会存在还原剂耗量大的问题.为降低杂质离子对金还原的影响，文中引入了添加剂X，通过添加剂X的使用优化铁粉置换硫脲金的过程.进行了在添加剂作用下铁粉还原酸性硫脲浸金液中金的试验研究，具体考察了添加剂X用量、反应时间、反应温度、搅拌转速及铁粉用量对金还原率的影响.试验结果表明:在添加剂用量为0.02 g/L，反应时间为90 min，反应温度35 ℃，搅拌转速为300 r/min，铁粉用量为0.2 g/L的较优条件下，金的还原率接近100 %.并进行了有无添加剂X的对比试验，验证了添加剂X的使用对铁粉还原酸性硫脲浸金液中的金有明显的促进效果.      

镍基高温合金中Fe、Mo的联合测定

试样经酸溶解后,用同一母液对镍基高温合金中Fe、Mo进行联合测定。采用EDTA掩蔽干扰元素后直接进行铁量的测定,硫脲作还原剂测定钼量,两元素线性良好。该方法简便快速,已用于实际样品的测定,结果令人满意。     

Kinetics of the competitive degradation of deoxyribose and other biomolecules by hydroxyl radicals produced by the Fenton reaction

The objective of this work is to reexamine the competitive degradation of deoxyribose by hydroxyl radicals (.OH) produced by the reaction between H2O2 and Fe(2+)-EDTA. The .OH radicals produced attack deoxyribose (D, rate constant kD) and eventually an .OH scavenger (S, rate constant kS). First, we examined the effect of [D], [H2O2], [Fe(2+)-EDTA], [EDTA]/[Fe2+] ratio and reaction time on the rate of D degradation, measured as the absorbance of the chromogen formed between the product of the reaction D + .OH (malondialdehyde) and thiobarbituric acid. In particular, it was showed that under our experimental conditions ([D] = 3 mM, [H2O2] = 0.85 mM, [Fe2+] = 0.13 mM), the rate of overall process is first order in Fe2+, zero order in H2O2 and is maximal for a ratio [EDTA]/[Fe2+] = 1.1. Second, the kinetics of .OH radical reaction in competition experiments between D and S (mannitol) was investigated. The results show that the ratio of the rates of D degradation in the absence (VD) and in the presence (VDS) of S should be represented by VD/VDS = 1 + ks[S]/(kD[D] + kx) where kx accounts for the rate of .OH reactions with other reagents such as Fe(2+)-EDTA, H2O2 etc . . . After having determined kx for each set of experimental conditions, we obtained the values of kS/kD by determining the variations of VD/VDS as a function of [S] and [D]. By taking kD = 1.9 x 10(9) M-1s-1 a value of kS = 1.9 x 10(9) M-1s-1 was obtained, very close to that obtained by pulse radiolysis. Finally, the validity of the established relation was confirmed for other biomolecules (methionine, k = 5.6 x 10(9)M-1s-1 and alanine, k = 3.3 x 10(8) M-1s-1). By contrast, it was not applicable to cysteine, thiourea and mercaptoethanol which was attributed to an interaction of the latter scavengers with Fe2+ and/or H2O2.     

某尾渣硫脲浸出金试验研究

对某尾渣,在比较了硫脲、硫氰酸铵、硫代硫酸钠浸金效果的基础上,选择硫脲为浸出刺。试验通过优化浸出条件,确定硫脲质量浓度为15g／L、硫酸用量为55mL、液固比为3、搅拌浸出3h,金的硫脲浸出率可达到93．50％。试验还考察了硫脲溶液循环使用效果,可在一定程度上降低浸金过程中硫脲的消耗。     

基体匹配—铬天青S分光光度法测定铅锭中铝

试样采用稀硝酸-EDTA溶解;在HAc-NaAc缓冲溶液中,铝与铬天青S形成稳定的红色络合物,于波长550 nm处测其吸光度;采用抗坏血酸,硫脲掩蔽Fe3+、Cu2+等干扰,标准溶液中加入相应量的铅消除基体干扰。RSD(n=9)<7.00%,回收率103.5%~109.5%,可准确测定铅锭0.005%~0.1%铝。     

硫脲树脂对Cu~(2+)吸附性能研究

考察了不同吸附时间、pH值和吸附温度下,聚对苯甲酰基硫脲树脂和聚酯基硫脲树脂对Cu2+的吸附性能影响;并对吸附动力学和热力学进行了研究。     

液膜分离富集与测定工业废水中痕量铊

研究了ＴＢＰ,聚丁二烯,磺化煤油,ＴＵ和Ｎａ２ＳＯ３溶液乳状液膜体系中,Ｔｌ＾３＋的迁移行为,在选择条件下Ｔｌ＾３＋的迁移率达９９．４％以上。该条件下许多金属离子如Ｃｕ＾２＋,Ｐｂ＾２＋,Ｚｎ＾２＋,Ｃｏ＾２＋,Ｎｉ＾２＋,Ｃｄ＾２＋,Ｃａ＾２＋,Ｍｇ＾２＋,Ｆｅ＾３＋,Ａｌ＾３＋,Ｍｎ＾２＋Ａｕ＾３＋等都不被迁移,只有Ｔｌ＾３＋能与这些金属离子得到彻底的分离富集,用于富集测定工业废水中痕量铊,结