基于聚合物复合电极的MCDI技术处理重金属废水的过程机制

For the characteristics of existing heavy metal wastewater and the treatment methods have high running cost，unstable effect, serious secondary pollution and so on, applicant put forward that introduce ion exchange membrane to the energy saving and environmental protection technology of capacitive deionization(CDI), a new membrane capacitance method for the treatment of heavy metal wastewater combined ion exchange membrane with CDI was built. Aim at the key problems of the traditional conductive polymer electrode，including the poor electrochemical stability and cyclic adsorption performance, made conductive polymer and chitosan recombined, through the research contents include as following: the preparation of composite electrode materials with core - shell structure of the polymer/crosslinked chitosan, the moulding conditions of conductive composite electrode material are optimized, the mechanism of electrode adsorption/desorption of metal ions. The composite mechanism of conductive polymer and crosslinked chitosan, the strengthen approach of metal ion mass transfer rate based on membrane capacitance method and its removal rule of heavy metal ions in waste water are revealed; illuminating the correlation between electrode characteristic and its surface properties，electrochemical performance，diffusion mass transfer and adsorption / desorption process of ions in the electrode，and the relevant theoretical model will be founded in order to achieve valid approach of improving the electric adsorption performance, charge efficiency, electrode regeneration performance and strengthening the metal ion mass transfer rate. Research results provide the basis of relevant data for practical application of MCDI technology, as well as provide ideas and methods for the treatment and resource efficient recycling of waster water in Non-ferrous metal smelting.

针对重金属废水特点及现有处理方法存在的运行成本高、效果不稳定、二次污染严重等现状，申请人提出将离子交换膜引入到节能环保的电容法去离子（CDI）技术中，建立离子交换膜与CDI相耦合的膜电容法处理重金属废水的新方法（MCDI）。针对传统导电聚合物电极电化学稳定性和循环吸附性能较差等关键问题，将导电聚合物与壳聚糖复合，通过对核-壳结构的聚合物/壳聚糖复合电极材料的制备、成型条件的优化及电极吸附/解吸金属离子机理等研究，揭示导电聚合物与交联壳聚糖的复合机制、膜电容法强化金属离子传质速率的途径及脱除废水中重金属离子的规律；阐明电极特征与其表面性能、电化学性能、离子在电极中的扩散传质及吸附/解吸过程的相关性，建立相应模型，以期获得提高电吸附性能、电荷效率、电极再生性能及强化金属离子传质速率的有效途径。研究成果为MCDI技术的实用化提供相关基础数据，同时也为相关冶金废水处理及资源高效回收提供思路与方法。

本项目针对重金属废水的特点及现有处理方法存在的运行成本高、处理不彻底、二次污染严重等现状，开展了下述研究并取得了相关研究结果。.（1）将导电聚合物与壳聚糖复合，以三氯化铁为氧化剂，十二烷基苯磺酸钠为掺杂剂制备了核-壳结构的复合材料，考察了壳聚糖、聚吡咯、FeCl3、SDBS等因素对复合材料性能的影响规律。采用热压成型法以聚吡咯/壳聚糖复合材料为电极活性基体、加入导电剂、不添加黏结剂的方法制备了聚吡咯/壳聚糖复合电极。通过对电极成型条件优化等研究，获得了高吸附性能、良好电化学稳定性及机械性能，可用于重金属废水处理的电极材料及电极成型工艺参数。.（2）通过原位聚合法制备了PPy/CS/CNT复合纳米材料，在不添加黏结剂的条件下将其压制成电极。将GO通过原位聚合法添加到PPy/CS/CNT复合纳米材料中，制备出了PPy/GO/CS/CNT复合纳米材料。研究过程中对PPy/CS/CNT及PPy/GO/CS/CNT复合纳米电极的表面形貌、官能团种类、抗压强度、电化学性能、稳定性进行了测试分析。将PPy/CS/CNT复合纳米电极应用于CDI/MCDI技术，考察了该电极对重金属离子的吸附性能。探究了不同种类复合纳米电极、离子初始浓度、电极电压及离子种类等对吸附过程的影响规律。.（3）采用制备的复合纳米电极，设计完成了 CDI 和 MCDI脱除重金属离子的组件，重点考察了电极对离子的吸附特性。通过研究组件的电吸附性能、电荷效率、吸附动力学及热力学等特性及电极的再生性能，建立了离子交换膜与CDI相结合的膜电容法处理重金属废水的新方法，进行了导电聚合物电极吸附金属离子的机理研究，探究其形貌特征对其表面性能、电化学性能、以及离子在电极中的扩散传质和吸附过程的影响规律。研究结果为该环境友好工艺的实用化提供了相关基础数据。