Cellulose-type binder enabling CuCl2 supported on nanoporous bayerite to have high CO adsorption ability via reduction of Cu2+ to Cu

Previously, we developed a powder-form nanoporous CO-selective adsorbent synthesized via thermal monolayer dispersion of CuCl on bayerite, showing high CO adsorption capacity (48.5 cm 3 g −1 ) and a high CO/CO 2 selectivity (12.4). For its industrial applications, it is necessary to pelletize it, avoiding pressure-drop problems. Here, we demonstrate a facile three-step method of pelletizing a CuCl/bayerite: 1) physical mixing of CuCl, methyl-cellulose, inorganic-binder, and bayerite, 2) pelletizing, and 3) thermal treatment at 573 K under vacuum. The pelletized adsorbent shows high CO adsorption capacity (42 cm 3 g −1 ), CO/CO 2 selectivity (12), and commercial-level mechanical strength (1.3 kg f ). Notably, the added methyl-cellulose binder has reducing role that maintains the initial CO adsorption capacity for 100 days’ exposure to humid air-condition, although CuCl-based adsorbent easily lost CO adsorption ability owing to oxidation of Cu + to Cu 2+ . CuCl 2 , showing no specific interaction with CO, was converted to Cu + by the methyl-cellulose. Thus, adsorbent prepared using CuCl 2 instead of CuCl with the methyl-cellulose also showed high CO adsorption capacity (31.6 cm 3 g −1 ) and maintained the initial capacity after seven days’ exposure. The reducing role of the methyl-cellulose binder allows inexpensive and feasible synthesis of the CO-adsorbent using CuCl 2 that can be easily dispersed on bayerite, without additional reduction treatment.