Energy-efficient capture of volatile organic compounds from humid air by granular metal organic gel.

Abstract The discovery of granular adsorbents for the capture of volatile organic compounds (VOCs) from humid air and rapid regeneration at low temperature is still a challenge. Here we reported formation of a granular Al-based metal organic gel, CAU-3-NH2(gel), by adjusting heating up time in the synthesis procedure. The water and thermal stable xerogel shows high surface area (1964 m2/g) and adsorption capacity for VOCs (uptakes of toluene and hexanal reach 4.5 and 3.85 mmol/g at P/P0 = 0.1, respectively). Dynamic adsorption experiments further conformed its outstanding adsorption performance for toluene under 50% RH, higher than that of commercial adsorbents and widely studied MOFs including BPL activated carbon, ZSM-5, zeolite 13X, XAD-16, MIL-101(Cr), CAU-1 and ZIF-8. Under the mass space velocity of 12,000 mL/g.h, CAU-3-NH2(gel) kept 99.95% removal ratio of low concentration toluene (100 ppm) over 12 h in 3 cycles at 298 K. Furthermore, desorption experiments show its excellent regenerability under mild temperature (328 K and 358 K). The interaction of toluene-framework and adsorption process are investigated by using Grand Canonical Monte Carlo (GCMC) simulations.