Computer Simulation Of The Properties Of Aqueous Solutions And Adsorption Processes In Activated Carbon Pores

With the development of computer science and technology, computer simulation has been becoming a powerful tool in studying both structures and properties of real fluids. It has also been drawn great attention in chemical engineering field. Compared with the traditional method, computer simulation has its special advantages. By performing computer simulation on model fluids, microscopic and macroscopic properties can be revealed, and many physical phenomena can also be discovered and interpreted. Moreover, the macroscopic properties of real fluids can be predicted from the interaction between molecules. In this work, we use the molecular simulation method to calculate the properties of infinite dilute aqueous solutions, to study the hydrophilicity of organic substances in supercritical aqueous solutions and to investigate adsorption processes of fluids in slit pores.At first, five water potential energy models have been investigated by the NPT ensemble Monte Carlo(MC) method, and the transferable intermolecular potential function for four points(TIP4P) model is considered as the best model for simulating the properties of water and aqueous solutions at normal temperatures and pressures. The Henry constants and activity coefficients for methane and benzene in infinite dilute aqueous solutions have been simulated by the NPT ensemble thermodynamic integration with the coupling parameter method. The preferential sampling method has been used for improving the efficiency of the simulation. The TIP4P and the optimized parameters by liquid simulation(OPLS) are proposed for the description of the molecular interactions for water and organic substances, respectively. The Ewald method has been incorporated into the long range correction for the interaction between water molecules. The simulated errors are in fair agreement with the literature data, which indicates that the method used in this work can be applied to the predication of the properties for organic substances in infinite dilute aqueous solutions.The hydrophilicity of benzene in supercritical aqueous solutions has been investigated by the canonical(NVT) ensemble method. The simple point charge(SPC) model and the Lennard-Jones(LJ) model with OPLS parameters have been adopted for the description of interactions between water and benzene molecules, respectively. The effects of the variables, including temperature, concentration and density in 10 cases on the hydrophilicity of benzene have been investigated. The microstructures and the radial distribution functions(RDFs) of the aqueous solutions describe the behavior of benzene molecules changing from hydrophobic to hydrophilic, taking place in the supercritical conditions. As a result, an appropriate condition for benzene molecules dissolving homogeneously in the supercritical water is recommended for the design of reaction...