土壤重金属溶出伏安检测中腐殖质干扰机理及抑制方法研究

溶出伏安法作为一种电化学分析技术可与修饰电极结合检测重金属离子，但由于土壤腐殖质会影响电极修饰层的理化性质，且易与重金属离子络合影响其电沉积过程，大大降低了土壤重金属溶出伏安检测精度。本项目以重金属Cd(II)和Pb(II)为检测对象，采用溶出伏安法，分析腐殖质在电极表面修饰层的吸附特征，研究腐殖质吸附对电极电化学属性和表面形貌的影响，探索腐殖质吸附对电极表面动力学特性的干扰机理；分析腐殖质与重金属离子的络合程度及络合物电活性，研究腐殖质-重金属络合物对重金属离子电沉积的干扰特性；研究紫外光解对腐殖质吸附能力的削弱机制，探索紫外光解对腐殖质-重金属络合物的解络机理；更进一步探索H₂O₂高级氧化对紫外光解过程的催化机制，优选光照强度、照射时间和光程长度，提出一种可通过H₂O₂/紫外光解来抑制腐殖质干扰的新方法，实现腐殖质这一普遍存在干扰因素下的土壤重金属溶出伏安高效精准检测。

As an electrochemical analysis technology, stripping voltammetry can be used for the rapid and accurate detection of heavy metal ions (HMIs) combining with modified electrodes. However, the humus in soil will affect the physicochemical properties of electrode modification layer, and the humus is easy to complex with HMIs and then affect the electrodeposition process of HMIs, which leading to the decrease of the stripping voltammetry detection accuracy. In this project, the adsorption characteristics of humus on the electrode surface modification layer will be analyzed, the influence of humus absorption on electrochemical properties and morphology of electrode surface will be investigated, the interference mechanism of humus adsorption on the kinetics characteristic of electrode surface will be explored, which taking Cd(II) and Pb(II) as detection target, based on stripping voltammetry; The complexation degree between humus and HMIs and the electroactivity of HMIs in complex compound will be analyzed, the interference characteristics of humus-HMIs complex compound on the electrodeposition process of HMIs will be studied; The weakening mechanism of ultraviolet (UV) photolysis to humus absorption will be investigated, the decomplexation mechanism of UV photolysis to humus-HMIs complex compound will be explored; The catalytic mechanism of advanced oxidation of H₂O₂ on the UV photolysis process will be further explored, the light intensity, irradiation time and optical path length will be optimized, a method for humus interference inhibition based on H₂O₂/UV photolysis will be proposed, which is used to achieve the accurate and efficient stripping voltammetry detection of HMIs in soil, in the presence of ubiquitous interference from humus.