Study About The Removal Of Drug Pollutants From Water By Adsorption Over Metal-organic Frameworks

Drug pollutants in waste water may cause serious damage to environment and human health,so it is very important for us to study the removal of them.In this paper,we try to remove the drug contaminants in waste water by adsorption using the material called metal-organic frameworks(MOFs),which is a new type of cellular material.MOFs have a lot of advantages over traditional porous materials,such as large surface area,high porosity,high thermal stability and so on.Also,the structure of metal-organic frameworks can be controlled by changing organic ligands used.In our study,we mainly study the typical beta-lactamide antibiotics cefradine,and two typical nitroimidazoles,secnidazole and tinidazole.They are all heterocyclic drugs.The detailed process is as follows:1.According to the π-complexation mechanism,we select PCN-222,which is synthesized by using porphyrins,to remove the cefradine in water.Firstly,PCN-222 materials were synthesized and characterized,and the structure of the material is proved to be right.Then,the material was used for the adsorption experiment and show the highest adsorption capacity.The effect of time,concentration and coexisting ions on adsorption was also researched.The adsorption mechanism of PCN-222 on cefradine is mainly attributed to the conjugate mechanism.One-dimensional pore and the electrostatic incorporation are also important reasons for high adsorption.2.Based on the mechanism,we use the Al-TCPP material,which is also made with porphyrins as organic ligands,to remove tinidazole molecule in water,and it shows the highest adsorption capacity of seknitazole.The whole research process includes the synthesis,characterization,adsorption experiment and the verification of the influence of time,concentration and coexisting ions.As a conclusion,The adsorption is mainly contributed by two-side pi-pi conjugate.At the same time,the experiments with different pH conditions excluded the electrostatic interaction in the whole process.3.We select a research sequence,which includes screening,performance study and mechanism study,to find the suitable material to remove the tinidazole in the water.From 10 kinds of MOFs,which we usually use in the liquid phase adsorption,we find that the CAU-1 has the highest adsorption capacity.The material is characterized in detail to prove that the structure of the synthesized material is reliable.And then,adsorption experiment is carried out,the effect of time,concentration,and the coexisting ions on the adsorption is also researched.Results indicate that the CAU-1 exhibites the highest adsorption capacity so far.The characteristic Al-O-Al structure unit in CAU-1 is the main reason that why CAU-1 exhibit high adsorption capacity.At the same time,the-NH2 in the organic ligands of the materials will have a hydrogen-bond interaction with the-NO2 group in the molecule of tinidazole,the effects of electrostatic and competitive adsorption also affect the adsorption effect.Also,after multiple cycles,the material retains more than 99%of its adsorption capacity,which means that CAU-1 is reusable.