Optimized Porous Clay Heterostructure For The Romoval Of Acetaldehyde And Toluene From Indoor Air

Adsorption is the most widely used technology for the removal of indoor volatile organic compounds (VOCs). However, adsorbent-based technologies currently available cannot achieve the regulatory required removal of VOCs from indoor air because of the issues related to their limited adsorption capacity and efficiency especially under high relative humidity (RH) conditions. To this end, a series of new porous clay heterostructure (PCH) adsorbents with various ratios of micropores to mesopores were synthesized, characterized and tested for the adsorption of acetaldehyde and toluene. Two PCH tested, PCH25 and PCH50, exhibited markedly improved adsorption capability, especially for hydrophilic acetaldehyde. Improved adsorption was found to correlate with their large micropore areas and high micropore-to-mesopore volume ratios, and the saturated adsorption capacities increased with increasing total pore volume. The saturated adsorption capacities onto PCH25 were 2.2 and 1.3 times higher than those onto AC for acetaldehyde and toluene, respectively. The removal rate of acetaldehyde by PCH25 at an RH of 20% achieved 89.0%, and a similar trend was obtained for PCH50. The removal rate of toluene onto PCH50 at RH of 20% achieved 90.0%. Even at a high RH of 80%, PCH25 removed ten times more acetaldehyde than AC, and 2.5 times more toluene than PCH0. This novel PCH optimized for their high adsorption and resistance to humidity has promising applications as a cost-effective adsorbent with promising applications for indoor air purification.