Preparation Of Iron-based MOF Composites And Their Adsorption Properties

The problem of water pollution has seriously affected the sustainable development of human society,and water pollution treatment technologies have caused widespread concern.Currently,many methods have been developed for treating polluted wastewater,such as adsorption,biological treatment,coagulation/flocculation,membrane filtration,degradation and dialysis.Among them,the adsorption method has the advantages of simple,effective and low cost.MOFs material have many advantages,such as rich pores,large specific surface area,and easily modified pore structure.They have great prospects in adsorption-related applications.However,in practical applications,single MOF has disadvantages such as water resistance,light resistance and poor mechanical properties.Therefore,the combination of MOFs and functional materials to form composites has attracted widespread attention.Compounding can not only avoid the shortcomings of MOFs,but also increase their performance.How to improve the adsorption performance and reduce the material cost is still an area of concern for MOFs composite materials.In this paper,cheap montmorillonite(Mt)was used as an carrier,which was combined with iron-based MOF to prepare eco-friendly and cheap MIL-53(Fe)@Mt,MIL-100(Fe)@Mt composite adsorbents.The MIL-100(Fe)flower cluster adsorbent(MIL-100(Fe)/SA)was prepared by using sodium alginate(SA)as structure inducer Meanwhile,the adsorption properties of MIL-53(Fe)@Mt,MIL-100(Fe)@Mt and MIL-100(Fe)/SA composite adsorbents were studied.The content of the thesis is as follows:1.Firstly,the development history and main types of MOFs materials were introduced.Secondly,the different MOFs composite materials and their properties were summarized.Finally,we outlined the main types and of iron-based MOFs,the applications of iron-based MOFs and composite materials.In addition,the application of iron-based MOFs and composite materials in wastewater treatment was introduced as a key.2.Using montmorillonite as a carrier,MIL-53(Fe)was combined through in-situ growth technique,which afforded MIL-53(Fe)@Mt,a novel cheap and eco-friendly adsorbent.The structure of MIL-53(Fe)@Mt was characterized by SEM,FT-IR,XRD,BET and TG.The results showed that MIL-53(Fe)particles grew on the surface of the layered montmorillonite,and MIL-53(Fe)particles become smaller.Finally,the adsorption properties of MIL-53(Fe)@Mt were investigated,and the results showed that MIL-53(Fe)@Mt had excellent adsorption performance for methylene blue,and the removal rate reached 99.6%in 50 minutes.Compared with pure MIL-53(Fe)and Mt,the adsorption capacity of MIL-53(Fe)@Mt for MB was 3.02 and 3.54 times that of pure Mt and MIL-53(Fe),respectively.3.The MIL-100(Fe)@Mt,a novel cheap and eco-friendly adsorbent,was afforded by combining montmorillonite and MIL-100(Fe)under fluorine-free conditions through in-situ growth technique.The structure of MIL-100(Fe)@Mt was characterized by SEM,FT-IR,XRD,BET and TG.The results showed that the MIL-100(Fe)grew uniformly on the surface of the layered Mt,and the Mt layer became looser.The adsorption performance of MIL-100(Fe)@Mt was investigated The results showed that MIL-100(Fe)@Mt had the enhanced adsorption performance for RhB,and the removal rate reached 99.0%in 30 minutes.4.Using the natural polymer sodium alginate as a structure inducer,it was crosslinked with Fe3+ions to form gel beads,and then MIL-100(Fe)flower clusters(MIL-100(Fe)/SA)were prepared in a hydrothermal reaction.The structure of MIL-100(Fe)/S A was characterized by SEM,FT-IR,XRD,XPS and BET.The results showed that SA was successfully decomposed in the hydrothermal process.Under the induction of SA,as-prepared MIL-100(Fe)was a cauliflower-like flower cluster structure formed by small particles of 50～70 nm.The particles are 2 to 3 times smaller than pure MIL-100(Fe).Furthermore,the adsorption performance of MIL-100(Fe)/SA was investigated.The results showed that MIL-100(Fe)/SA had outstanding adsorption performance for TC,and the removal rate reached 99.1%in 40 minutes.In this paper,three kinds of novel iron-based MOF composite materials were prepared through in-situ growth technique.The composite materials display excellent adsorption performance on pollutants in water,as well as have the advantage of low cost,non-toxic and eco-friendly,which is expected to be applied in the field of water treatment research.