Stable Aluminum Metal Organic Frameworks (Al-MOFs) for Balanced CO2 and Water Selectivity

Three new Al-MOFs in the formation of [Al-4(OH)(2)(OCH3)(4)(OH-BDC)(3)]center dot xH(2)O (BIT-72), [Al-4(OH)(2)(OCH3)(4)(CH3-BDC)(3)]center dot xH(2)O (BIT-73) and {Al-4(OH)(2)(OCH3)(4)[(CH3)(2)-BDC](3)}center dot xH(2)O (BIT-74) have been synthesized by assembling Al3+ ion with terephthalic acid ions decorated with monohydroxyl, monomethyl or dimethyl groups, respectively. All of these three MOFs exhibit high stability in boiling water and acidic conditions. Among them, BIT-72 shows the highest surface area of 1618 m(2).g(-1) and LAST CO2/N-2 selectivity of 48, while BIT-73 and BIT-74 present moderate LAST CO2/N-2 selectivity and much lower H2O capacity below P/P-0 = 0.3. The high CO2/N-2 selectivity together with alleviative H2O sorption at low water relative pressure may provide promising potential in postcombustion CO2 capture.