Here, p is the pressure expressed in Pa, N is the amount
absorbed in mol g-1, T is the temperature in K,ai and bj are Virial
coefficients, and m , n represent the number of
coefficients required to adequately describe the isotherms. The values
of the Virial coefficients a0 througham were then used to calculate enthalpies
(Q st) of absorption using (eq. 4)25.