耦合离子交换功能的絮凝剂去除垃圾渗滤液膜浓缩液中有机物的特征和机理研究

The landfill leachate treatment has always been a hot issue in water treatment. The application of nanofiltration and reverse osmosis realized the standard discharge of landfill leachate. However, the resultant membrane concentrate brings an emerging pollution. The removal of organic matters from the membrane concentrate is the most difficult. Coagulation is a preferred technology for the present combined process of membrane concentrate treatment, and its performance directly influences the engineering feasibility of the combined process. Recently, the applicant prepared a new kind of flocculants with an ion-exchange function by introducing organic functional groups to the skeleton of inorganic flocculants through covalent bond. The flocculants substantially broaden the types and increase the removal efficiency of organic matters. This project intends to propose a new method to remove organic matters from landfill leachate concentrate by using the novel flocculant; to intensively investigate the characteristics of the flocculation process under the unique conditions of high salt and antiscalant; to focus on the rules that how flocculation performance influenced by the composition and structure of the organic pollutants, the type and structure of the antiscalant, high salinity, and the morphology and structure of the flocculant; to define the relationship between the flocculant structure and the efficiency of the organic matter removal activity; and to clarify the flocculation mechanism; to propose the method and theory of "tailor-made" for membrane concentrate treatment. The project will provide theoretical and technical basis for the optimization of the coagulation or the coagulation-based processes for the treatment of different types of landfill leachate concentrate.

垃圾渗滤液处理一直是水处理领域关注的热点问题。纳滤和反渗透的应用保证了垃圾渗滤液处理达标排放，但随之产生的膜浓缩液成为新兴污染，而其中有机物的去除是浓缩液处理的难点。混凝是目前浓缩液组合处理工艺首选的技术之一，其效果直接影响到组合工艺的工程可行性。申请者通过在无机絮凝剂骨架上以共价键嫁接有机官能团制备了耦合离子交换功能的新型絮凝剂，该絮凝剂拓宽了絮凝去除有机物的种类范围并大幅提高了絮凝效果。本项目提出采用该絮凝剂去除垃圾渗滤液膜浓缩液中有机物的新方法，深入研究浓缩液特有的高盐和阻垢剂条件下该絮凝剂对有机物的絮凝特征，重点研究有机污染物的组分和结构、阻垢剂的类型和结构、高盐条件、絮凝剂的形态结构对絮凝效果的影响规律，确定此特殊处理条件下絮凝剂的构效关系并阐明其絮凝机理，提出针对膜浓缩液处理的絮凝剂"量身定制"方法和理论。本项目可为不同类型浓缩液的混凝处理及其组合工艺优化提供理论和技术依据。

垃圾渗滤液膜浓缩液处理是水处理领域的难点问题，而其中有机物去除是关键。本项目采用电喷雾傅里叶变换离子回旋共振质谱（ESI FT-ICR MS）手段从分子水平详细表征渗滤液膜浓缩液溶解性有机物（DOM）的组成及性质，研发了耦合离子交换功能的共价键型絮凝剂（CIEX），探究了膜浓缩液水质条件、絮凝剂类型及絮凝方式对絮凝效果的影响规律，利用CIEX实现了垃圾渗滤液膜浓缩液高效处理。本研究结论归纳如下：.不同膜浓缩液DOM性质较为相似，主要含有CHO、CHON、CHOS以及CHONS四类有机物质，其相较于天然有机物有较大差别；膜浓缩液DOM芳香性及腐殖化程度较低；有机物质种类丰富，特别是含N、S元素有机物种类多，亲水性小分子含量高；分子饱和度高，氧化程度低。絮凝和生物处理膜浓缩液具有互补性，絮凝可有效去除膜浓缩液中生物过程不能去除的或生物过程自身产生的有机物。.采用缓慢滴碱法，利用无机原料聚合硫酸铁、聚合氯化铝及有机原料3-三乙氧基硅基丙基三甲基氯化铵等分别研制了铁系和铝系CIEX。通过制备条件优化，大幅提高了絮凝剂中能够去除水中小分子有机物的功能基团含量。分子模拟发现絮凝去除小分子污染物主要依靠静电吸附与疏水吸附，为CIEX的量身定制提供了依据。.利用CIEX实现了垃圾渗滤液膜浓缩液的高效处理。探究了CIEX投加方式对絮凝效果的影响，发现两步絮凝法处理膜浓缩液效果最好。第一步絮凝主要去除悬浮颗粒物、胶体等大分子物质（包括大分子胡敏酸及富里酸类物质），第二步絮凝主要去除溶解性腐殖质及溶解性微生物产物等，两步絮凝可使COD去除率达90%以上。该技术已在工程规模上示范和推广应用，取得了良好的经济效益、环境效益和社会效益。本研究为新型絮凝剂研制和应用提供了新思路，为渗滤液膜浓缩液等特种废水的经济高效处理提供了解决途径和理论依据。