Impermeable polymer coating on selected honeycomb channel surfaces

A method for forming an absorbent structure for CO2 capture, the method comprising:

• providing a honeycomb substrate formed from a sorbent material, the honeycomb substrate having partition walls that extend through the honeycomb substrate in an axial direction from an inlet surface of the honeycomb substrate to an outlet surface of the honeycomb substrate opposite the inlet surface, the partition walls having channel surfaces that define a plurality of individual channels, the plurality of individual channels comprising a plurality of reaction channels and a plurality of heat-exchange channels, whereby the channel surfaces of the reaction channels are reaction-channel surfaces and the channel surfaces of the heat-exchange channels are exchange-channel surfaces;
• masking inlet ends and outlet ends of each of the reaction channels to form masked reaction channels;
• delivering a first aqueous polymer emulsion onto the inlet surface of the honeycomb substrate to cause the first aqueous polymer emulsion to flow through each of the heat-exchange channels and not to flow through the masked reaction channels, thereby forming a first emulsion coating of the first aqueous polymer emulsion over the exchange-channel surfaces only;
• and
• drying the first emulsion coating to form a water-impermeable layer on the exchange-channel surfaces,
• wherein:
• the water-impermeable layer comprises a polymer material selected from the group consisting of poly(vinyl butyral) resins, polyacrylates, polynitriles, polychloroprenes, poly(vinyl chloride), poly(vinylidene fluoride), polyolefins, poly(tetrafluoroethylene), silicones, polyurethanes mixtures thereof, and composites thereof;
• and
• the polymer material of the water-impermeable layer does not substantially penetrate into the partition walls that form the exchange-channel surfaces.

A method for forming an absorbent structure for CO2 capture, the method comprising:

• providing a honeycomb substrate formed from a ceramic material and loaded with a sorbent material, the honeycomb substrate having partition walls that extend through the honeycomb substrate in an axial direction from an inlet surface of the honeycomb substrate to an outlet surface of the honeycomb substrate opposite the inlet surface, the partition walls having channel surfaces that define a plurality of individual channels, the plurality of individual channels comprising a plurality of reaction channels and a plurality of heat-exchange channels, whereby the channel surfaces of the reaction channels are reaction-channel surfaces and the channel surfaces of the heat-exchange channels are exchange-channel surfaces;
• masking inlet ends and outlet ends of each of the reaction channels to form masked reaction channels;
• delivering a first aqueous polymer emulsion onto the inlet surface of the honeycomb substrate to cause the first aqueous polymer emulsion to flow through each of the heat-exchange channels and not to flow through the masked reaction channels, thereby forming a first emulsion coating of the first aqueous polymer emulsion over the exchange-channel surfaces only;
• and
• drying the emulsion coating to form a water-impermeable layer over the exchange-channel surfaces,
• wherein:
• the water-impermeable layer comprises a polymer material selected from the group consisting of poly(vinyl butyral) resins, polyacrylates, polynitriles, polychloroprenes, poly(vinyl chloride), poly(vinylidene fluoride), polyolefins, poly(tetrafluoroethylene), silicones, polyurethanes mixtures thereof, and composites thereof;
• and
• the polymer material of the water-impermeable layer does not substantially penetrate into the partition walls that form the exchange-channel surfaces.