基于协同高效去除Cr和挥发性有机硫化物调控沸石分子筛结构及其去除机理研究

The increasingly serious water pollution of chromium, air pollution of haze and the requirement of creating an added value from silica fume in China have attracted much attention. The project was focused on effectively removal chromium by the zeolites that prepared from raw material silica fume in a new route, and the spent adsorbent was employed to degradation volatile organic sulfur species. The new route of prepare zeolite was followed by pretreatment, mixing reactant in a new system with no additional solvent, modification, functionalization, and so on. In order to further explored the relationship between the structure of zeolite and the removal performance of chromium and volatile organic sulfur species, the zeolite before and after adsorption or catalysis were characterized by XRD, N2 adsorption-desorption isotherm, XPS, CO2-TPD, NH3-TPD, etc. And then, the excellent zeolites with high performance for removing chromium and volatile organic sulfur species were obtained by regulation the zeolite structure of physical and chemical. Additionally, based on the results of chromium adsorption behavior, the variation of adsorption active center, the catalytic degradation behavior of volatile organic sulfur species and the variation of catalyst structure, the mechanisms of adsorption chromium species and catalysis degradation volatile organic sulfur species were investigated. In light of these researches, a new synthesized approach of environment friendly, green and cheap were explored. Furthermore, excellent economic, social and environmental benefits will also be achieved. And the results, which obtained in this project, provide the foundation of theoretical knowledge and experiment data to prepare excellent adsorbent, catalyst and other environment functional materials from silica fume.

本项目针对我国日益严重的水体铬污染、雾霾以及微硅粉高值资源化需求，提出拟以微硅粉为原料，通过运用预处理、构建无外加溶剂的固相反应体系、改性和功能化，将微硅粉制备成沸石分子筛来去除水体中铬，并利用废弃铬吸附剂来协同去除雾霾源之一的挥发性有机硫化物，实现微硅粉的高值资源化。同时，借助XRD、N2吸脱附等温线、XPS、CO2-TPD和NH3-TPD等手段，揭示材料理化结构与其去除铬和挥发性有机硫化物性能间的关联，通过对理化结构的调控来研制出有高吸附性能和优良催化性能的沸石分子筛。此外，通过对铬吸附行为和吸附剂官能团变化的分析来揭示吸附机理，通过分析挥发性有机硫化物的降解行为和催化剂理化结构的变化来揭示催化反应机理。本研究既提供一种环境友好且廉价的高性能环境功能材料制备方法，又可获得良好的经济和环境效益。研究成果可为我国微硅粉高值资源化制备优良吸附剂、催化剂和其它环境功能材料奠定较好的理论基础。

工业废渣微硅粉作为冶炼硅铁或工业硅的必然副产物，我国每年约产生150万吨，但目前主要应用在附加值较低的水泥和混凝土行业，且利用率较低，大部分仍然是堆存放置，故对微硅粉进行高附加值应用研究显得尤为重要。项目选用云南工业硅生产厂产生的微硅粉为原料，通过添加硅盐、模板剂和助剂来构建固相反应体系得到高附加值的高硅沸石分子筛ZSM-5；并通过碱液提取微硅粉中硅源，在模板剂P123作用下，构建液相反应体系，得到高附加值的分子筛材料SBA-15。致癌物铬不能依靠生物进行降解去除，我国每年仅皮革行业就产生1.8亿吨含铬废水，吸附法是去除Cr(VI)的有效有段之一，但废弃吸附剂的处理极大的限制其广泛应用；硫酸盐气溶胶是雾霾的主要成分之一，目前关于有机硫化物的去除研究较少。因此，本项目研究者通过固、液相体系将微硅粉制备成高效铬吸附剂，并将废弃铬吸附剂作为催化剂来去除挥发性有机硫化物。. 项目实施中成功依托微硅粉合成出纳米零价铁修饰ZSM-5、硫化纳米零价铁修饰ZSM-5、氨基功能化ZSM-5和不同链长氨基功能化SBA-15这四个Cr(VI)吸附剂。通过材料表征和Cr(VI)吸附吸附实验结果发现：硫化手段可有效的影响零价铁的稳定并提高Cr(VI)去除能力，但硫源类型的不同会影响所得复合材料的结晶度和晶格结构等，Na2SO3修饰过的复合材料纳米零价铁-ZSM-5对Cr(VI)的吸附容量高达200.1 mg/g，主要是硫化所得FeS2更有利于电子传递和氧化还原反应的发生。在Cr-ZSM-5材料去除挥发性有机硫化物甲硫醇的研究中发现，2%Cr-ZSM-5在450 oC反应体系中的甲硫醇转化率为98%，且较为稳定，在反应20 h后甲硫醇转化率才出现降低的现象，在反应24 h后甲硫醇转化率仍然大于70%。. 现已发表16 篇学术论文，其中12篇SCI 收录、2 篇EI 收录，已申请发明专利2 项、其中1项已授权，培养硕士研究生3 名、博士研究生1名。