In this work we screened the interactions of 53 pharmaceuticals and agents of personal care products with 14 all-silica zeolites on the force field level of theory. Beforehand, three small molecules forcefields and three sets of parameters for silica were validated against rev-vdW-DF2/TZVP interaction energies. We found that the Sage OpenFF 2.0 forcefield in combination with parameters for SiZeo and OZeo developed by Emami et al. were able to reproduce the DFT-D IEs quite well. To account for the conformational space of the PPCPs, a conformational search was carried out before insertion and a geometric prescreening was performed to reduce the computational cost. The evaluation of the interaction energies indicates that, in general, for flexible molecules the IE increases as the pore diameter decreases until a critical pore size is reached. Below this pore size, deformation is required to fit into the narrow pores, resulting in a decrease of IE. For rigid molecules, the topology of the pores becomes more important. A "good fit" between the pores and the molecule has the strongest influence on the IE. A descriptor, taking the rotatable bonds and the (annulated) rings of the molecule into account was developed and applied to classify the molecules as either flexible or rigid. Free Energy Perturbation simulations were applied to investigate a test set of ten PPCPs in two zeolites and in aqueous solution to obtain Free Energies of Transfer from the aqueous phase to the adsorbed state. The simulation results were found to be in good agreement with the experimental values, paving the way towards more quantitative predictions of adsorption from aqueous solution.