Chemical speciation of chromium(III,VI) employing extractive spectrophotometry and tetraphenylarsonium chloride or tetraphenylphosphonium bromide as ion-pair reagent
Chemical speciation of chromium(III,VI) employing extractive spectrophotometry and tetraphenylarsonium chloride or tetraphenylphosphonium bromide as ion-pair reagent
复制标题
DOI：
10.1016/j.aca.2004.11.085
复制
发表时间：
2005-04
影响因子：
6.2
通讯作者：
M. El-Shahawi;S. Hassan;A. Othman;M. A. Zyada;M. A. El-Sonbati
中科院分区：
文献类型：
--
作者：
M. El-Shahawi;S. Hassan;A. Othman;M. A. Zyada;M. A. El-Sonbati
本文提出了一种简单、准确的萃取光度法测定水介质中铬（Ⅲ，Ⅵ）的化学形态。该方法是基于在pH≤0的氯仿中萃取氯铬酸根（CrO 3Cl −）阴离子与离子对试剂氯化四苯胂（TPAs+Cl−）或溴化四苯基鏻（TPP+Br−）之间形成的络合离子缔合物，然后在355 nm处直接进行分光光度测量。用Beer-Lambert定律、Ringbom曲线、摩尔吸光系数、Sandell灵敏度、萃取常数和稳定常数（KD、Kex和β）、化学计量比和萃取平衡等确定了最佳浓度范围，为该体系的分析应用提供了方便。铬（III）也被确定的建议程序后，预先氧化铬酸盐与H2 O2在碱性溶液。该方法已成功地应用于电镀厂工业废水中Cr（VI）和总Cr（III，VI）的分析。
A simple and accurate extractive spectrophotometric procedure for the chemical speciation of chromium(III,VI) species in aqueous media has been developed. The method is based upon the extraction of the complex ion-associate formed between the chloro chromate (CrO3Cl−) anion and the ion-pair reagent tetraphenylarsonium chloride (TPAs+Cl−) or tetraphenylphosphonium bromide (TPP+Br−) at pH≤0 in chloroform followed by direct spectrophotometric measurement at 355nm. The optimum concentration range evaluated by Beer–Lambert's law, Ringbom's plot, the molar absorptivity, the Sandell's sensitivity, the extraction and stability constants (KD, Kexand β), the stoichiometry and the extraction equilibria of the produced complex ion-associates have been determined and gave a convenient applications of the investigated system for analytical purposes. Chromium(III) was also determined by the proposed procedure after prior oxidation to chromate with H2O2in alkaline solution. The method has been applied successfully for the analysis of chromium(VI) and total chromium(III,VI) in industrial wastewater of electroplating plant.