Potable water extraction from the atmosphere: Potential of MOFs.

This communication addresses the Adsorptive Extraction of potable Water from the Atmosphere (AWEA) in arid areas using solar energy. The method includes a) adsorption of water vapor from the air at night-time, and b) desorption of the stored water and its subsequent collection in a condenser in the day-time. Metal-organic frameworks (MOFs), being crystalline porous solids with unique adsorption properties, might provide a promising avenue for AWEA. First, the thermodynamic requirements for adsorbent optimal for AWEA are formulated. The optimal adsorbent (OA) has energy different adsorption centers with the affinity distributed in a wide range of adsorption potential between Δ F ad and Δ F re , corresponding to the adsorption and regeneration stages, respectively. For three arid climatic zones (the Sahara Desert, Saudi Arabia and Central Australia), the quantitative requirements to the OA are formulated in terms of the Δ F ad and Δ F re values. The selection of MOFs, promising for the AWEA, is carried out. The most promising MOFs for Australia are MIL-101(Cr), Co 2 Cl 2 (BTDD), and MIL-101(Cr)–SO 3 H. MIL-160 and CAU-10(pydc) are appropriate for Saudi Arabia and Sahara. They exchange 0.34–1.6 (g water)/(g adsorbent) and allow getting the fractions δ ex = 0.78–0.93 of water extraction and δ col = 0.75–0.90 of water collection at the regeneration temperature 75–100 °C. • Adsorption method of fresh water extraction from air (AWEA) using MOFs is discussed. • Thermodynamic requirements for the adsorbent optimal for AWEA are formulated. • The most promising MOFs as adsorbents for AWEA are selected. • Fractions of water extraction and collection in AWEA using selected MOFs are evaluated. • Effects of the adsorbent, regeneration and condensation temperatures are considered. [ABSTRACT FROM AUTHOR]