Formic acid modulated (fam) aluminium fumarate MOF for improved isotherms and kinetics with water adsorption: Cooling/heat pump applications

Abstract This article presents the synthetization and characterisation of fam (formic acid modulated) Al Fum (aluminium fumarate) MOFs. The parent Al Fum MOFs are modulated with 5 ml, 10 ml and 15 ml of formic acid for comparison purposes. The characteristics of newly developed fam Al Fum are presented by TEM and PXRD analyses. N 2 volumetric adsorption is performed to evaluate the porous properties of fam Al Fum. It is found that Al Fum particles start to elongate with the addition of formic acid and the synthesis duration is greatly reduced. An increase in micro pores distribution is observed for 10 ml of formic acid added to the parent Al Fum MOFs. Water adsorption isotherms and kinetics are measured by a gravimetric analyser. It is found that fam Al Fum MOFs improve the water vapour uptake rates as compared with the parent Al Fum. The addition of 10 ml formic acid into Al Fum MOF shows the best performances in terms of uptake-offtake difference (Δq), which is 12.5% higher than that of the parent Al Fum MOF. The isosteric heat of adsorption is also calculated. The improved isotherms and kinetics results indicate fam Al Fum as potential adsorbent for heat transmission applications.