A solar-thermal vapor-permeation membrane is provided. The solar-thermal vapor-permeation membrane includes a thermally conductive, microporous support layer having a feed surface, and an active separation layer adjacent the feed surface of the support layer. The support layer is capable of absorbing solar-thermal radiation. Utilization of solar energy for a membrane separation process replaces fossil-fuel derived energy with renewable energy as the driving force and does not involve the generation of undesirable greenhouse gas emissions. Therefore, the solar-thermal vapor-permeation process using the provided membrane is cost effective, energy efficient, and environmentally friendly.