Nemez Dion B, Lewis Casey, Trokajlo Peter, Liang Yuming, Goldman Dov, Motnenko Irena, Herbert David E
Department of Chemistry, University of Manitoba, 144 Dysart Road, Winnipeg, Manitoba R3T 2N2, Canada.
Osorno Enterprises Inc., 976 Elgin Ave, Winnipeg, Manitoba R3E 1B4, Canada.
ACS Omega. 2023 Oct 13;8(42):39616-39624. doi: 10.1021/acsomega.3c05490. eCollection 2023 Oct 24.
Accurate and cost-effective methods for the analysis of oxychlorine compounds in water are critical to modern chlorine-based water treatment. With alternatives to elemental chlorine and hypochlorite bleaches growing in popularity, simple quantification methods for the disinfectant chlorine dioxide (ClO) in water, as well as chlorite (ClO) and chlorate (ClO), which are commonly used precursors in ClO generation, are required. However, currently, regulated standard methods require specialized equipment and do not effectively discriminate between molecular and ionic species. In this contribution, we present a simple titration-based method for chlorite determination in water using commercially available and easy-to-handle reagents. Specifically, chlorite is reduced with a slight excess of thioureadioxide (TUD). The remaining reductant is then back-titrated against a known amount of potassium permanganate, affording calculatable chlorite concentrations through measured consumption of a reductant and a clear visual endpoint upon accumulation of excess KMnO. Straightforward methods for chlorite standardization with reasonable error and accuracy for field and/or lab application have the potential to greatly enhance quality assurance and therefore assist in resource deployment in water treatment.
准确且经济高效的水中氯氧化合物分析方法对现代氯基水处理至关重要。随着元素氯和次氯酸盐漂白剂的替代物越来越受欢迎，需要用于水中消毒剂二氧化氯（ClO₂）以及亚氯酸盐（ClO₂⁻）和氯酸盐（ClO₃⁻）（它们是ClO₂生成中常用的前体）的简单定量方法。然而，目前，规定的标准方法需要专门的设备，并且不能有效地区分分子和离子物种。在本论文中，我们提出了一种基于滴定的简单方法，使用市售且易于操作的试剂来测定水中的亚氯酸盐。具体而言，用略微过量的二氧化硫脲（TUD）还原亚氯酸盐。然后用已知量的高锰酸钾对剩余的还原剂进行返滴定，通过测量还原剂的消耗量以及过量KMnO₄积累时清晰的视觉终点来得出可计算的亚氯酸盐浓度。具有合理误差和准确性的亚氯酸盐标准化的直接方法，适用于现场和/或实验室应用，有可能极大地提高质量保证，从而有助于水处理中的资源配置。
