造纸废水中几种可溶性硫形态的方波伏安法分析

Simultaneous Determination of Several Dissolvable Sulfur Species in Papermaking Wastewater by Square Wave Voltammetry

造纸废水中含有多种形态的硫,对其测定较为困难。运用方波伏安法对造纸废水中的硫化合物存在形态进行了同时分析。0.02mol·L-1NaOH介质中,含S2-溶液在汞膜电极上具有灵敏方波伏安还原峰,峰电位为-0.72V(vs.SCE),峰型对称而尖锐,峰电流ip1的高低与S2-的浓度具有良好的线性关系。测定后的底液中加入适量的冰醋酸,使溶液pH4.5(NaAc-HAc缓冲溶液),-0.56V(vs.SCE)和-0.10V(vs.SCE)分别出现两个方波伏安还原峰,峰电流ip2和ip3分别可以用于SO32-和S2O32-的含量测定。方法简单、快速,适合造纸废水中无机可溶性硫化合物的同时形态分析。

Papermaking wastewater contains a variety of species of dissolvable sulfur,and its determination is difficult. Modern square wave voltammetry was used for the simultaneous determination of several dissolvable sulfur species in the wastewater. In the media of 0.02mol·L^-1 NaOH,a well defined square wave reduction peak was found in the S2-ion containing solution when mercury film electrode was used as the working electrode,the peak potential was -0.72V（vs.SCE） and the height of the peak ip^1 was linear with the concentration of S^2- ion. Appropriate glacial acetic acid was added to make the pH of the above solution be 4.5 （just as a NaAc- HAe buffer solution）. Two square wave reductions peaks -0.56V（vs.SCE） and -0.10V（vs.SCE） corresponding to SO3^2- and S2O3^2- were also appeared, and the heights of ip^2 and i9 can be used for the determination of SO3^2- and S2O3^2- concentrations in the wastewater. The proposed method was simple and fast, and with satisfied results when used for the real sample analysis.