Methane dense storage in ZIF-8@cu under low pressure via adsorption-absorption synergy

In order to enhance CH 4 adsorption and absorption performance, ZIF-8@Cu was prepared by precipitation method at room temperature, while a hydrate accelerator of SO 3 − @PSNS was synthesized by the polymerization method, and CH 4 adsorption-absorption synergistic storage in ZIF-8@Cu that pre-adsorbed SO 3 − @PSNS solution was evaluated for the first time. It was found that Cu 2+ can effectively improve the adsorption kinetics of CH 4 , causing ZIF-8@Cu to reach a higher adsorption capacity, and CH 4 adsorption capacity of ZIF-8@Cu /0.14% is 12.45 % higher than that in ZIF-8. Furthermore, Cu 2+ provides additional nucleation sites for CH 4 hydrate, thereby enhancing the overall CH 4 storage density. For the water content of R w  = 0.5, the doping of 0.14 % Cu 2+ causes CH 4 storage capacity via adsorption-absorption synergy increases by 33.93 %. It is worth to note that SO 3 − @PSNS significantly reduces hydration pressure while retains CH 4 adsorption ability in ZIF-8@Cu. For R w  = 0.5, hydration pressure in SO 3 − @PSNS system reduces by up to 45 % compared with that in water system, while CH 4 storage capacity increases by up to 94 %. This finding makes it possible for CH 4 dense storage under low pressure via adsorption-hydration hybrid approach.