Effects of properties of minerals adsorbents for the adsorption and desorption of volatile organic compounds (VOC)

In this study, adsorption and desorption performance of three mineral adsorbents (diatomite, clinoptilolite, and palygorskite) was investigated for abatement of six VOC with distinct physical and chemical properties and functional groups. Among the three mineral adsorbents, palygorskite exhibited the highest adsorption capacity for all the tested VOC as indicated by the adsorption breakthrough curves. Characterization of the adsorbents showed that palygorskite had the highest specific surface area and pore volume. The distinct adsorption capacities of minerals for VOC can be attributed to the difference of VOC's boiling point and polarity. Increasing the adsorption temperature and relative humidity decreased adsorption capacity of the minerals for VOC. Non-polar VOC showed more sensitivity to changes in temperature and relative humidity compared to polar VOC. Desorption performance of the mineral adsorbents was studied in 5-cycle adsorption/desorption experiments. The results indicated that the desorption purge gas has no significant impact on desorption efficiency. However, increasing desorption temperature clearly decreased the cumulative heel on the adsorbent. Moreover, non-polar VOC desorbed better from the mineral surface than polar VOC.