Investigating the Adsorption Behavior of Cobalt based Metal-organic Framework Nanoplates in Desulfurization of Oil Model

The adsorption properties of uniform nano-plate cobalt based metal-organic framework of [Co6(oba)6(CH3O)4(O)2]n·3DMF (TMU-11NP) for removal of dibenzothiophene (DBT) has been investigated. TMU-11NP can be obtained quickly and easily via sonochemical method. The effect of particle size reduction and enhancement of surface area from 630 to 838 m2/g and changing the morphology from the agglomeration of particles to regular nanoplates has increased the absorption capacity of DBT from 825 to 1666.6 mg/g. The selectivity test of DBT over naphthalene (NA) clearly shows that π-π interactions between organic linkers of TMU-11 and the aromatic ring of DBT are not responsible for the adsorption desulfurization (ADS) process. The synergistic effects of reducing the particle size and subsequently, increasing the surface area and increasing the accessibility of inactive unsaturated coordination sites around one of the cobalt centers, as well as the uniform morphology of the plates, have led to the observation of such results. Also, nano particles of Co3O4, obtained from calcination of TMU-11NP, show higher DBT removal performance (300 mg/g) compared to its commercial counterpart (83 mg/g). The adsorption mechanism of DBT in the presence of TMU-11NP adsorbent was investigated and it was found to follow the Langmuir model. Our findings may offer a new approach to producing adsorbents with preferable performance in practical applications.