基于零价纳米铁的新型高效多功能复合材料的设计和性能研究

With small particle size, large specific surface area and high reactivity, the nanoscale zero-valent iron(nZVI) has been utilized to remove a wide array of environmental contaminants in the remediation of soils and groundwater. The application of nZVI is limited seriously due to its tendency of aggregation and oxidation, thus suitable modification methods are needed. According to the structural characters of polyaniline(PANI) with functional group and attapulgite(APT) with high specific area and a rich number of pores, the research work will develop a novel method to use PANI and APT as composite support for modification nZVI. Among them, APT of support material as dispersant role can disperse nZVI to prevent the aggregation, PANI as a stabilizer can effectively prevent the oxidation of nZVI by oxygen in the air and accelerate electron transfer between the iron particles and contaminants. Therefore, the reactivity and stability of nZVI are greatly increased by using PANI and APT in the composite materials. Due to the synergistic effects of adsorption and degradation of PANI, APT and nZVI, PANI/APT supported nZVI composites can be used as a kind of efficient, multifunctional and low cost material for removal of both heavy metal ions and organic dyes from wastewater. In this work, the effect of PANI/APT composite support on the reactivity and stability of nZVI will be systematically studied. The removal properties of heavy metal ions and organic dyes and corresponding mechanism will be investigated, and the synthesis methods are optimized. The relation can be realized among the component, structure and removal properties of PANI/APT supported nZVI. Consequently, it will provide a new approach for design and practical application of nZVI composites.

纳米零价铁材料具有粒径小，比表面积大，表面活性高，还原能力强等性能，能有效去除多种污染物，但易于团聚和氧化使其在应用中受到极大限制。研究课题根据聚苯胺和凹凸棒的结构特征，提出一种基于纳米铁表面修饰改性的新方法，将含有功能基团的聚苯胺和具有孔道结构、高比表面积的凹凸棒作为复合载体引入纳米铁的改性，凹凸棒作分散剂能够有效降低纳米铁团聚，聚苯胺作稳定剂能有效防止纳米铁氧化，其具有的导电性可使铁在发生氧化、还原降解污染物时加速电子转移，提高纳米铁的稳定性和反应活性。同时聚苯胺与凹凸棒复合载体对污染物有很好的吸附性能，三者协同作用，可作为一类高效多功能、低成本水处理复合材料用于重金属离子和有机染料等污染物去除。项目研究力图揭示聚苯胺/凹凸棒复合载体对纳米铁的详细作用机制，研究复合材料对污染物的去除性能和机理，优化合成方法，建立材料组成、结构和性能的关系，为纳米铁复合材料的构建和实用化开拓新的途径。

纳米零价铁（nZVI）可有效去除多种污染物，但易于团聚和氧化使其在应用中受到极大限制。研究项目根据凹凸棒（APT）和导电聚合物(PANI、PPy)等载体的结构特征，将具有孔道结构、高比表面积的APT和含有功能基团的PANI、PPy等材料作为复合载体引入nZVI的改性，提高其稳定性和反应活性。项目研究揭示了凹凸棒、导电聚合物等复合载体对nZVI的作用机制，探究复合材料对水体污染物的去除性能和机理，优化合成方法，建立材料组成、结构和性能的关系，为nZVI复合材料的构建和实用化开拓新途径。主要研究内容和结果如下：.1.优化导电聚合物/APT复合载体的制备条件，提升其对污染物的吸附性能。研究结果表明：APT的表面修饰，导电聚合物的合成条件对复合材料吸附性能有较大影响，继而影响负载纳米铁对污染物的去除性能。.2.研究APT、导电聚合物等载体对nZVI的作用以及对水体污染物的去除性能和去除机理，在此基础上探讨nZVI复合体系与Fenton氧化相结合对污染物的去除。结果表明：天然黏土APT能有效分散nZVI，对提高其反应活性和复合材料的吸附性能具有非常重要的作用。含有功能基团的PANI、PPy不仅通过静电吸引、离子交换和氢键等作用对水体污染物进行吸附，还可加快电子传递速率，提高反应速率，且能有效防止nZVI的氧化，提高其反应活性和稳定性，三者协同作用，可作为一类高效多功能、低成本水处理复合材料用于污染物去除。将导电聚合物/APT负载nZVI与Fenton反应结合，可广泛用于重金属离子和有机污染物的环境修复治理。.3.根据载体结构多样性，开发APT、PANI系列复合载体负载nZVI，提升其反应活性。此外结合硫化、金属掺杂等nZVI表面改性技术，拓宽nZVI复合材料的实际应用领域。