MoS2 Nanosheets Functionalized Composite Mixed Matrix Membrane for Enhanced CO2 Capture via Surface Drop-Coating Method

Molybdenum disulfide (MoS2) is a graphene-like two-dimensional inorganic material, which has been used for the first time as an inorganic nanofiller to prepare a composite mixed matrix membrane to separate CO2 and N2. Polysulfone (PSf) was used as a support substrate and poly­(dimethylsiloxane) (PDMS) was used as the gutter layer. The selective layer was prepared by mixing a CO2-philic copolymer Pebax 1657 with MoS2 nanosheets to enhance CO2 permeance. In addition, a simple drop-coating and evaporation method was developed to prepare the selective layer. Both permeability and selectivity of the MoS2–Pebax membrane have exceeded the pristine Pebax membrane. The permeability and selectivity reached to the maximum values of 64 Barrer and 93, respectively, at 0.15 wt % MoS2 nanosheets loadings. This result has been on the Robeson’s upper bound line. The membrane also showed higher stability. The separation mechanism of the membrane is based on the well-known solution-diffusion mechanism. In addition, the stronger adsorption energy of MoS2 nanosheets to CO2 than N2 also provides the enhancement of gas selectivity.