A VOC (volatile organic compounds) adsorbent material is treated with a masking agent to reduce its affinity for VOC's to a level that the material can be regenerated at a predetermined low temperature which will not desorb the masking agent. Preferably, the adsorbent material is a water adsorbent desiccant which is treated with water vapor. The treated adsorbent material is used to adsorb VOC's from gas and is periodically regenerated with heated air. The desorbed VOC's may be destroyed by oxidizing, for example, with a catalyst.

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