𝑝 , denotes the equilibrium NH3 partial pressure in the gas phase in Pa and 𝑝°= 1 Pa is the reference pressure. The sorption equilibrium constant 𝐾° (eq. ( )) can be calculated from the sorption enthalpy 𝛥𝐻° = -87.048 kJ mol and entropy 𝛥𝑆° = -230.88 J mol K as given by Neveu and Castaing 33 for the reverse reaction and the reference pressure of 𝑝°= 1 Pa.