Molecular Simulation Study of the Adsorption and Diffusion Properties of Terephthalic Acid in Various Metal Organic Frameworks

Adsorption and diffusion of terephthalic acid (TPA) molecules in metal organic frameworks of MIL-101(Cr), MIL-100(Cr), Cu-BTC, DUT-23(Cu), UIO-66 and UMCM-2 from water are investigated by using molecular simulation at ambient temperature and pressure. The simulation results indicated that UMCM-2 and UIO-66 have the greatest (1894.19 mg/g) and the lowest (199.67 mg/g) TPA adsorption, respectively, and diffusion coefficients of TPA in MIL-101(Cr) (12.10 x 10(-10) m(2)/s) and UMCM-2 (9.70 x 10(-10) m(2)/s) are higher than the others. Also, MIL-101(Cr) is modified with other metal ions such as Al, Fe, Mn and V, due to having the highest diffusion coefficient and acceptable adsorption amount of TPA, and then their adsorption and diffusion properties for TPA molecules are investigated. According to simulation results, the adsorption and diffusion of TPA is changed by changing metal cations in MIL-101(M) structure and MIL-101(A1) structure is the best absorbent with the TPA adsorption and diffusion coefficient 1869.78 mg/g and 15.51 x 10(-10) m(2)/s, respectively.