Molecular Dynamics Simulation To Explore The Organic Molecular Adsorption Mechanism Of Metal-organic Framework UiO-66

Metal-organic frameworks(MOFs)are a kind of organic-inorganic composite functional and porous materials.Compared with traditional mesoporous materials,MOFs have excellent properties such as stable chemical properties,high porosity,large specific surface area and rich functional variable sites.They are widely used in gas adsorption and storage,catalysts,sensors,drug carriers and other fields.In this paper,the molecular dynamics simulation(MD)is used to study the metal-organic frameworks Ui O-66 in drug adsorption and sewage treatment,which provides data reference and theoretical support for improving the drug loading and sewage treatment.The main research contents of this paper are:(1)Drug carriers can effectively delay the duration of drugs,specifically identify the action site,and reduce toxic and side effects.We have theoretically studied the adsorption effect and mechanism of Ui O-66 on three drug molecules(busulfan,5-fluorouracil,ibuprofen)by molecular dynamics simulation,the adsorption capacity of different drugs is different.The simulation results show that Ui O-66 has better adsorption effect on busulfan molecules,while 5-fluorouracil and ibuprofen molecules have poor adsorption effect by Ui O-66.By calculating the radial distribution functions,interaction energy,number of contact atoms and potential of mean forces between Ui O-66 and drugs,we further confirmed that the charged group in the drug molecule can promote the adsorption of Ui O-66.(2)Phenolic organic pollutants are highly toxic organic compounds,mainly coming from industrial wastewater such as chemical industry and coal gas,causing the water pollution.However,it is difficult to remove them from industrial wastewater.The adsorption method has the advantages of simple operation,low cost and high efficiency.In this paper,the adsorption mechanism of three phenolic organic pollutants(phenol,nitrophenol and bisphenol)by Ui O-66 was studied using molecular dynamics simulations.Analyzing and calculating the number of hydrogen bonds,π-π stacking,radial distribution function curve,interaction energy between Ui O-66 and phenolic organic pollutants,root mean square displacement of phenolic organic pollutants,etc.The results show that the adsorption effect of Ui O-66 on nitrophenol is the best,while the adsorption effect of bisphenol and phenol is not good.Organic molecules with negative charge groups in phenols are easily adsorbed in Ui O-66.Therefore,Ui O-66 is suitable as an adsorbent for nitrophenol wastewater.(3)In order to improve the adsorption efficiency of phenol molecules by Ui O-66,we combined the electrostatic field with adsorption treatment by molecular dynamic simulations.To explore the effect of electrostatic field with different intensities(1V/nm,3V/nm,5V/nm)and directions(vertical and parallel to the direction of Ui O-66)on the adsorption of phenol.The results show that the adsorption efficiency of phenol molecules can be significantly improved by applying electric field parallel to the Ui O-66,and the greater the electric field intensity is,the more phenol molecules will be adsorbed in Ui O-66.When a negative electric field is applied in the vertical direction,the adsorption effect of phenol molecule is poor.The stronger the electric field is,the less the amount of phenol molecule adsorption is.The calculation results of diffusion coefficient and dipole value confirmed that the electric field with different directions and intensities had great influence on the adsorption results of phenol by UiO-66.