基于粉煤灰固相无溶剂及假晶转变法制备高效介孔砷吸附剂及机理研究

The project was focused on the increasingly serious water pollution of arsenic and the requirement of creating an added value from fly ash in China. Fly ash, a byproduct of coal fired power station, was used as the raw materials to prepare arsenic adsorbent in this project. We proposed a green and environment friendly route to synthesis arsenic adsorbent by removing impurities from fly ash, mixing surfactant and assistant ingredient with no additional solvent, pseudomorphic transformation, and then modified by organic or inorganic active component. In order to further explored the relationship between arsenic removal performance and the structure of adsorbents, adsorbents were characterized by ICP, XRD, N2 adsorption-desorption, TEM, FT-IR, XPS, etc. And then, the adsorbent with high performance for removing arsenic were obtained by the regulation of adsorbent structure. Additionly, the study of adsorption kinetic, thermodynamic, desorption, regeneration, and the variation of adsorption active center were also investigated to analyze the adsorption mechanisms. In light of these researches, a new synthesize method of environment friendly, green and cheap were explored, which also offer an approach to effective utilization of fly ash. And the results, which obtained in this project, provide the foundation of theoretical knowledge and experiment data to prepare other environment materials from fly ash.

本项目针对我国日益严峻的水体砷污染问题和大量堆存粉煤灰的高值资源化需求，提出拟以燃煤电厂粉煤灰为原料，通过运用简单除杂、固相无溶剂反应、假晶转变法以及活性组分的负载，将粉煤灰制备成介孔砷吸附剂，实现其高值资源化利用。同时，借助ICP、XRD、N2吸脱附等温线、TEM、FT-IR和XPS等表征手段，揭示材料理化结构与砷吸附性能间的关联性，通过对吸附剂理化结构的调控来制备高性能砷吸附剂。此外，利用吸附动力学、吸附热力学和脱附、再生研究，以及对吸附前后吸附活性中心变化的分析，探索并揭示相关砷吸附机理。本研究既提供了一种环境友好且廉价的高效砷吸附剂制备方法，又为粉煤灰高值资源化利用提供一种途径。项目研究成果可为以粉煤灰为原料制备其它环境功能材料提供理论基础和实验数据依据。

我国燃煤电厂的燃烧固废粉煤灰年产量在5亿吨，目前其利用主要是水泥和混凝土行业，且利用率仅占50%，剩余的50%都是堆存放置，所以对粉煤灰进行高附加值的应用研究就显得尤为重要。项目选用的云南宣威电厂粉煤灰中氧化硅（57.09%）和氧化铝（19.43%）含量都较低，不适宜直接提取氧化硅和氧化铝这两种高附加值材料。类金属砷由于不能生物降解，且是多种矿物的伴生矿，故从水体中有效去除砷的研究就非常重要。因此，本项目研究者通过各种途径将云南宣威电厂粉煤灰制备成高砷吸附性能的吸附剂。·. 项目实施中依托粉煤灰成功合成出X沸石、壳聚糖功能化X沸石、柠檬酸铁功能化粉煤灰、Al-MCM-41和硫酸铈修饰的假晶转变ZSM-5这五个砷吸附剂。通过结合材料表征数据和砷吸附实验结果发现：X沸石和壳聚糖功能化X沸石可有效降低水体中砷浓度，且吸附剂表面的羟基官能团是影响砷吸附的主要因素；柠檬酸铁功能化粉煤灰可使500ppb初始浓度以下的含砷水体达到WHO关于饮用水中砷含量的标准；假晶转变确能改变微孔沸石的孔道结构，使沸石从原来的微孔材料转变为介孔孔道；介孔孔道结构比微孔孔道材料更有利于砷物种的吸附和活性组分的负载。. 现已发表9篇学术论文（3篇待刊），其中4篇SCI收录、1篇EI收录，已申请发明专利2项，培养硕士研究生3名。