You can look at RASPA by Snurr et al. (Dubbledam, Calero, Vlugt). It is made for gas adsorption and other simulations. They used to have a Fortran version called Music, but this is a revamped edition written in C.
GOMC is a GPU optimized Monte Carlo code for many things, adsorption is one of them. Likely a good starting place.
Cassandra by Maginn et al. is also used for gas adsorption in crystalline materials. It is Monte Carlo. This also has interface to the MoSDeF consortium.
You can also look at Towhee. You can do gas adsorption via grand canonical simulations, and probably others. This used to be Monte Carlo, and I think still is. It may also do Molecular Dynamics.
You can also use DL Monte, another Monte Carlo software, for gas adsorption.
Cory Simon's group also has software written in Julia for gas adsorption Simon Ensemble Git Repo
If you are after a program that can interface, I would lean towards Cassandra or RASPA since Cassandra has an interface to MoSDeF. There is a Monte Carlo code called BRiCK written by several authors involved in RASPA, and as such, there is a high probability of interfacing the two. Unfortunately for RASPA, while I have not used it myself, I know people who have, and they almost went insane :S
Unfortunately adsorption is largely done via Monte Carlo folks, and Monte Carlo software has not garnered the attention that Molecular Dynamics software has, so you won't find really high end software comparable to Gromacs/OpenMM/LAMMPS/AMBER/NAMD etc.