Immobilization of Cu3(btc)2 on graphene oxide-chitosan hybrid composite for the adsorption and photocatalytic degradation of methylene blue.

The graphene oxide (GO)-based materials are appealing channels for water treatment, their separation from water for recycle remains a task. The Cu3(btc)2 (btc = benzene-1,3,5-tricarboxylic acid) metal organic framework (MOF) was covalently immobilized onto chitosan (CS)/graphene oxide (GO) to form a catalyst material, which was subjected to characterization by XRD, FTIR, SEM, TEM, BET, and UV-vis diffusive reflectance spectra. MOFs are permeable crystalline compounds consisting of metal ions and polyfunctional organic ligands. The structural characterization revealed that the Cu3(btc)2 and chitosan were incorporated into the graphene oxide structure. The adsorption of MB by GO-CS@Cu3(btc)2 catalyst was clearly defined by Langmuir isotherm and pseudosecond order kinetic model. GO-CS@Cu3(btc)2 was found to possess an adsorption capacity of ~357.15 mg/g. The findings displayed the probability of reusing the catalyst material for several photocatalytic processes. The GO-CS@Cu3(btc)2 catalyst material exhibited 98% degradation of MB within 60 min under UV irradiation. The obtained MB degradation results were fitted onto a Langmuir-Hinshelwood (L-H) plot. The GO-CS@Cu3(btc)2 catalyst material exhibited high degradation efficiencies at neutral pH conditions. The results have shown that the GO-CS@Cu3(btc)2 catalyst material can be used as a catalyst for adsorption and as a photocatalyst for the efficient degradation of methylene blue from aqueous solutions.