Ho Bum Park

Increasing demands for energy-efficient separations in applications ranging from water purification to petroleum refining, chemicals production, and carbon capture have stimulated a vigorous search for novel, high-performance separation membranes. Synthetic membranes suffer a ubiquitous, pernicious trade-off: highly permeable membranes lack selectivity and vice versa. However, materials with both high permeability and high selectivity are beginning to emerge. For example, design features from bi

Graphene is a distinct two-dimensional material that offers a wide range of opportunities for membrane applications because of ultimate thinness, flexibility, chemical stability, and mechanical strength. We demonstrate that few- and several-layered graphene and graphene oxide (GO) sheets can be engineered to exhibit the desired gas separation characteristics. Selective gas diffusion can be achieved by controlling gas flow channels and pores via different stacking methods. For layered (3- to 10-n

Within a polymer film, free-volume elements such as pores and channels typically have a wide range of sizes and topologies. This broad range of free-volume element sizes compromises a polymer's ability to perform molecular separations. We demonstrated free-volume structures in dense vitreous polymers that enable outstanding molecular and ionic transport and separation performance that surpasses the limits of conventional polymers. The unusual microstructure in these materials can be systematical

Get the salt out: Conventional polyamide desalination membranes suffer from low chlorine tolerance, leading to short membrane life. Using newly synthesized sulfonated copolymers prepared by direct copolymerization of disulfonated monomer, chlorine-tolerant desalination membranes (see picture) showing high flux and high salt rejection were developed.

Material surface engineering has attracted great interest in important applications, including electronics, biomedicine, and membranes. More recently, dopamine has been widely exploited in solution-based chemistry to direct facile surface modification. However, unsolved questions remain about the chemical identity of the final products, their deposition kinetics and their binding mechanism. In particular, the dopamine oxidation reaction kinetics is a key to improving surface modification efficie

This paper reports a new polyimide design with high internal free volume elements for fast mass transport simultaneously with high selectivity. Here, we show that the polymer design using a three-dimensional rigid molecular structure having internal void space can lead to the formation of high fractional free volume with proper cavity size to separate small gas molecules with high selectivities as high permeabilities. These findings could strongly impact emerging gas separation applications usin

Abstract Highly permselective and durable membrane materials have been sought for energy‐efficient C 3 H 6 /C 3 H 8 separation. Mixed‐matrix membranes (MMMs) comprising a polymer matrix and metal–organic frameworks (MOFs) are promising candidates for this application; however, rational matching of filler‐matrix is challenging and their separation performances need to be further improved. Here, we propose a novel strategy of “defect engineering” in MOFs as an additional degree of freedom to desig

As water molecules permeate ultrafast through carbon nanotubes (CNTs), many studies have prepared CNTs-based membranes for water purification as well as desalination, particularly focusing on high flux membranes. Among them, vertically aligned CNTs membranes with ultrahigh water flux have been successfully demonstrated for fundamental studies, but they lack scalability for bulk production and sufficiently high salt rejection. CNTs embedded in polymeric desalination membranes, i.e., polyamide thi