M-BTC (M = Ga, Zr, Al, Cu) MOFs For The Efficient Removal Of Toxic Heavy Metal Ions From Water: Synthesis, Characterization And Adsorption Studies

Abstract

Simple 1,3,5-benzene tricarboxylic acid (BTC) linkaged metal organic frameworks (MOFs) with four different metal nodes namely Ga, Zr, Al and Cu were prepared by solvo-hydrothermal technique. These BTC MOFs were well characterized by adsorption-spectroscopic techniques to establish their structural, morphological and chemical characteristics. The unique and advantageous properties of MOFs such as micro crystallinity, microporosity and high surface area were responsible for their high adsorptive capacities in the removal of toxic heavy metal ions from aqueous solutions. Among the four different MOFs studied Ga-BTC MOF was recognized as a high potential and selective material for removal of heavy metal ions over the rest of the MOFs. It displayed greater selectivity for the adsorption of Pb2+ions with  a maximum adsorption capacity of 976 mg g-1 even without any specific N or S containing functional groups or magnetic component. The adsorption studies were carried out by estimating the amounts of heavy metal ions adsorbed by ICPOES analysis and confirmed from SEM-EDX data. It further exhibited reusability for 5 cycles with its structure remaining intact as observed from the XRD patterns.