n-Octyltrichlorosilane Modified SAPO-34/PDMS Mixed Matrix Membranes for Propane/Nitrogen Mixture Separation

Novel Polymeric Membranes Preparation and Membrane Process

Polymer-based membranes have advanced or novel functions in the various membrane separation processes for liquid and gaseous mixtures, such as gas separation, pervaporation (PV), reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF), microfiltration (MF), and in other critical applications of membranes such as water purification, solvent concentration, and recovery [...]

Recent Progress of SAPO-34 Zeolite Membranes for CO2 Separation: A Review

In the zeolite family, the silicoaluminophosphate (SAPO)-34 zeolite has a unique chemical structure, distinctive pore size, adsorption characteristics, as well as chemical and thermal stability, and recently, has attracted much research attention. Increasing global carbon dioxide (CO₂) emissions pose a serious environmental threat to humans, animals, plants, and the entire environment. This mini-review summarizes the role of SAPO-34 zeolite membranes, including mixed matrix membranes (MMMs) and pure SAPO-34 membranes in CO₂ separation. Specifically, this paper summarizes significant developments in SAPO-34 membranes for CO₂ removal from air and natural gas. Consideration is given to a variety of successes in SAPO-34 membranes, and future ideas are described in detail to foresee how SAPO-34 could be employed to mitigate greenhouse gas emissions. We hope that this study will serve as a detailed guide to the use of SAPO-34 membranes in industrial CO₂ separation.

Study of the Dissolution and Diffusion of Propane, Propylene and Nitrogen in Polydimethylsiloxane Membranes with Molecular Dynamics Simulation and Monte Carlo Simulation

Volatile organic compounds (VOCs) are important sources of atmospheric pollutants on account of their high recycling value. The membrane of dense silicone rubber polydimethylsiloxane (PDMS) has wide-ranging prospects for the separation and recovery of VOCs. In this study, PDMS membrane body models were established in BIOVIA Materials Studio (MS) to simulate VOCs with C3/N2 gases, and to study the structure of PDMS membranes and the dissolution and diffusion process of gas in the membranes. The free volume fraction (FFV), cohesive energy density (CED), radial distribution function (RDF), diffusion coefficient and solubility coefficient of C3H8, C3H6 and N2 in PDMS membranes were calculated, and the permeability coefficients were calculated according to these values. At the same time, the effects of temperature and mixed gas on the dissolution and diffusion of C3/N2 in PDMS membranes were investigated. The results show that the mass transfer process of C3 in PDMS membranes is mainly controlled by the dissolution process, while that of N2 is mainly controlled by the diffusion process. In a C3/N2 mixed gas system, there is a synergistic relationship between gases in the diffusion process, while there is competitive adsorption in the dissolution process. With an increase in temperature, the diffusion coefficients of the three gases in PDMS gradually increase, the solubility coefficients gradually decrease, and the overall permeability selectivity coefficients of the gases gradually decrease. Therefore, low-temperature conditions are more conducive to the separation of C3/N2 in PDMS membranes. The simulation results of the permeability selectivity coefficients of pure C3 and N2 in PDMS are similar to the experimental results, and the relationship between the micro- and macro-transport properties of PDMS membranes can be better understood through molecular simulation.