纳米三氧化二铁@金属-有机框架复合材料的制备、调控、及砷去除和机理研究

Arsenic is a kind of metalloid which commonly exists in the environment. The accumulation of its chemical compound would seriously harm the health of human. Therefore, the issue of arsenic pollution was highly concerned in recent years. Among these removal method of arsenic, Iron oxides become one of the best candidates, because of their low-cost and easily separated property. But, such method suffers some restrictions such as its glomeration and poor mechanical strength, often leading to low removal efficiency. Thus, loading Fe2O3 on material surface is developed to increase removal efficiency. However, low porosity and surface area in material lead to insufficient sorption capacity. To solve such bottleneck problem, we propose an in-situ synthesis of Fe2O3@MOFs to remove arsenic. Dependent on the structure and pore features, we expect to adjust some important factors of resulted Fe2O3 particle such as particle size, pore size, morphology, and specific surface area, consequently, clarifying the structure-activity relationship and the regulation mechanism, and establishing a new strategy for arsenic removal.

砷是一种高毒性类金属元素，其化合物积累会严重危害人类健康，因而近年来砷污染问题受到高度重视。吸附除砷法中，铁氧化物因价廉易得、容易分离等优势使其成为研究者首选除砷方法，但铁氧化物颗粒易团聚，孔结构和机械强度差等问题限制了其吸附容量和除砷效率。由此，近年来不少研究者致力于将铁氧化物负载于具有孔性和大比表面积的材料表面，从而增加其表面活性区域，提高砷吸附容量。然而其负载材料孔性和比表面性能一般导致材料吸附容量有限。本项目针对该瓶颈问题提出原位合成Fe2O3@MOFs复合材料，将Fe2O3负载在孔径大小、结构可调且具有‘苯酚’特征的系列MOFs材料表面，并用于砷去除。通过MOFs孔径大小、结构实现调控Fe2O3的粒子大小、形貌、孔径大小、比表面积等性能，建立MOFs--Fe2O3 --As三者之间的调控机制，阐明构效关系，建立Fe2O3与MOFs协同去砷新策略。

本项目按项目申报书设想和任务书要求，设计和制备了具有“苯酚”功能团的5种MOFs基体材料，采用“苯酚-Fe”表面反应策略，成功原位、快速制备出了MOF-74@Fe2O3、UTSA-74@Fe2O3、UiO-66(OH)@Fe2O3、UiO-66(OH)2@Fe2O3和Zn2(olz)@Fe2O3共5种MOFs@Fe2O3新复合材料。多种表征技术表明，这些新型复合材料克服了纳米Fe2O3易团聚、结构变化小、比表面积小的难题，且复合纳米Fe2O3的反应原位、简单、快速。系统研究了5种MOFs基体和5种对应的复合Fe2O3材料对不同价态砷的吸附条件、吸附热力学和动力学，探究了质子化、去质子化、大孔及“苯酚”基含量对吸附砷的影响。为水溶液中砷的去除提供了理论依据，也证实了材料具有高效除砷的应用前景，完成了该项任务书中各项要求。项目资助发表SCI期刊2篇、核心论文3篇、参加学生会议3次、培养硕士1名及本科生3人，均已取得相应的学位。项目投入经费38万元，支出32.2277万元，各项支出基本与预算相符。剩余经费5.7723万元，剩余经费计划用于本项目研究后续支出。