膨润土-钢渣复合颗粒处理重金属酸性矿山废水吸附-聚沉协同作用机理研究

For the situation of acid mine drainage containing heavy metal ions polluted environment seriously and there are many difficulties to deal with it ,the research was carried out by using bentonite-steel slag composite particles to remove heavy metal ions from the acid mine drainage ,which were characterized by high removing heavy metal ions and reducing acidity.The synergetic mechanism of adsorption-precipitation was investigated as well:The best preparation conditions of bentonite-steel slag composite particles were determined;The alkalinity release mechanism of composite particles and the adsorption mechanism、regularity and influencing factors on removal of heavy metal ion Fe2+, Mn2+, Cu2+ and Zn2+ have also been discussed in the proposal;The proposal studied the precipitation mechanism of heavy metal ions on the adsorbent surface,the occurrence state、re-adsorption of the adsorbent and the coagulation regularity of heavy metal.Meanwhile,the regularity of desorption of precipitate regenerates adsorbent was studied;It revealed the synergetic mechanism of adsorption-precipitation;This proposal set up reaction dynamics model ,used self-made mechanical agitation fluidized-bed to explore the mechanism of adsorption and to perfect the model.The result of research has certain significance to enrich the adsorption theory,and provides theoretical basis for composite particles used as an new effective and multifunctional materials.At the same time,it lays the foundation for the new method and material dealing acid mine wastewater.It has important theoretical significance and applied prospects for preventing and curing acid mine drainage pollution.

针对含重金属离子酸性矿山废水严重污染环境且处理难现状，结合焙烧改性制得的膨润土-钢渣复合颗粒吸附剂具有高效同步去除重金属离子和降低酸度的特性，开展膨润土-钢渣复合颗粒处理重金属酸性矿山废水吸附-聚沉协同作用机理研究：优选确定复合颗粒最佳制备条件；研究复合颗粒碱度释放机制和对重金属离子Fe2+、Mn2+、Cu2+及Zn2+等的吸附机理、规律和影响因素；研究重金属离子在吸附剂表面沉淀机理、沉淀的赋存形态、再吸附、絮凝重金属离子的聚沉规律和重金属沉淀脱附使表面吸附位获得再生规律；揭示复合颗粒吸附-聚沉协同作用机理；建立吸附-聚沉反应动力学模型，利用自制机械搅动流化床进一步验证机理、完善模型，研究成果对丰富吸附理论有一定意义，为复合颗粒作为新型高效多功能颗粒吸附材料提供理论依据，为开创处理酸性矿山废水新方法、新材料奠定基础，对防治矿山废水污染具有重要理论意义和应用前景。

针对含重金属离子酸性矿山废水严重污染环境且处理难现状，结合焙烧改性制得的膨润土-钢渣复合颗粒吸附剂具有高效同步去除重金属离子和降低酸度的特性，采用静、动态试验、宏、微观测试与理论分析相结合的方法对膨润土-钢渣复合颗粒的制备工艺、内在机理以及处理重金属酸性矿山废水的吸附-聚沉协同作用净化机理进行了全面、系统、科学和深入研究。确定了膨润土-钢渣复合颗粒制备的主要影响因素及影响规律，优选确定了膨润土-钢渣复合颗粒最佳制备工艺条件，揭示了复合颗粒制备过程的内在机理；研究确定了复合颗粒吸附剂释放碱度对pH值的调节机制，揭示了膨润土-钢渣复合材料与酸性矿山废水的作用机理；研究确定了复合颗粒对重金属离子Fe2+、Mn2+、Cu2+及Zn2+具有优良的吸附去除性能，揭示了重金属离子Fe2+、Mn2+、Cu2+及Zn2+共存时的竞争吸附规律和吸附机理，建立了复合颗粒吸附-聚沉重金属离子的多分子层吸附的BET等温模型和准二级反应动力学方程；揭示了复合颗粒对重金属离子Fe2+、Mn2+、Cu2+及Zn2+的吸附、化学沉淀作用发生于整个反应过程，揭示了内在反应作用主要是吸附、离子交换（晶格置换）、表面络合（配合）、化学沉淀作用以及颗粒表面形成沉淀后还会继续吸附重金属离子M并发生聚沉的吸附-聚沉协同作用的净化机理，确定了吸附-聚沉的重金属离子在吸附剂表面赋存形态主要以M-Si-O相结合矿物相以及MO(M(OH)2)、Ca-M-O、Ca-M-Si-O等稳定的残渣态形式存在；利用动态试验研究确定了降流非淹没式吸附柱为最佳运行工艺，并确定了最佳设计、运行参数，建立了Thomas动态吸附动力学模型，进一步验证了系统吸附-聚沉协同作用净化机理，完善了系统吸附-聚沉反应动力学模型。本研究成果吸附-聚沉理论对丰富吸附理论有一定科学意义，为复合材料制备及其具有中和、吸附-聚沉等多功能协同作用可作为新型高效颗粒吸附材料提供科学理论依据，为开创处理重金属酸性矿山废水新方法、新材料、新工艺奠定基础，对防治矿山废水污染具有重要理论意义和应用前景。