Recent advances on the membrane processes for CO_2 separation

Membrane separation technology has popularized rapidly and attracts much interest in gas industry as a promising sort of newly chemical separation unit operation. In this paper, recent advances on membrane processes for CO_2 separation are reviewed. The researches indicate that the optimization of operating process designs could improve the separation performance, reduce the energy consumption and decrease the cost of membrane separation systems. With the improvement of membrane materials recently,membrane processes are beginning to be competitive enough for CO_2 separation, especially for postcombustion CO_2 capture, biogas upgrading and natural gas carbon dioxide removal, compared with the traditional separation methods. We summarize the needs and most promising research directions for membrane processes for CO_2 separation in current and future membrane applications. As the time goes by, novel membrane materials developed according to the requirement proposed by process optimization with increased selectivity and/or permeance will accelerate the industrialization of membrane process in the near future. Based on the data collected in a pilot scale test, more effort could be made on the optimization of membrane separation processes. This work would open up a new horizon for CO_2 separation/Capture on Carbon Capture Utilization and Storage(CCUS).

Metal confined in metal-organic framework-based mixed matrix membranes for efficient butadiene recognition separation

The efficient separation of butadiene(1,3-C_(4)H_(6))from C_(4)hydrocarbons is a critical step in petrochemical processes.However,the traditional cryogenic distillation suffers from energy-intensity and serious environmental stress,necessitating the development of alternative technologies for efficient 1,3-C_(4)H_(6)separation.Herein,a 1,3-C_(4)H_(6)recognition mixed matrix membrane is reported via incorporating metal copper encapsulated a metal-organic framework(CuBTC@Cu)into elastic poly(dimethylsiloxane)(PDMS).The resulting CuBTC@Cu/PDMS membrane can efficient separate 1,3-C_(4)H_(6)from various C_(4)hydrocarbons including 1,3-C_(4)H_(6)/n-C_(4)H_(8),1,3-C_(4)H_(6)/iso-C_(4)H_(8),1,3-C_(4)H_(6)/n-C_(4)H_(10)and 1,3-C_(4)H_(6)/iso-C_(4)H_(10),yielding superior selectivity of 5.11,6.35,4.78,and 10.30,respectively,with 1,3-C_(4)H_(6)permeability of 53240 Barrer.Notably,the appropriateπ-complexation interaction between butadiene molecules and CuBTC@Cu as well as suitable transmission channel size enable the membrane only permeable to 1,3-C_(4)H_(6)and block the permeation of other C_(4)hydrocarbons,showing a unique 1,3-C_(4)H_(6)recognition behavior in membrane separation.The concept of affinity-relying separation combining molecular sieving would open a new direction for designing gas membranes for efficient light hydrocarbon separations.

Polymer-supported ultra-thin two-dimensional ZIF-L membranes through in-situ interface exfoliation for gas separation

Natural gas and biogas are important resources.The enrichment of CH4 is necessary for increasing the caloric value of feed gas[1-3].Membrane-based gas separation technology is more energyefficient with continuous operation and more environmentally friendly than conventional gas separation technologies,and it has strong application prospects in the field of industrial separation[1,4].Metal-organic frameworks(MOFs)have high porosity,adjustable aperture,highly diversified structures and satisfactory chemical stability,which inspire many researchers to explore their applications in membrane fabrication for gas separation[2,3,5].Pure MOF membranes that are fabricated on porous substrates can realize high gas permeance and satisfactory selectivity simultaneously and have been attracted substantial attention[6,7].