Adsorption of phenol red onto GO-Fe3O4 hybrids in aqueous media

Abstract

Phenol red is one of the most important cytotoxic dye that is prevalent in water systems in the vicinity of textiles and leather industries. Adsorption based processes with the use of functional ceramics and hybrids can be an efficient method for the removal of such dyes and subsequent treatment of water for human consumption. In this work, we have adopted sonication induced facile precipitation process to synthesize a hybrid of magnetite nanoparticles anchored on the surfaces of few layered graphene oxide. The morphology of the hybrid is such that restacking of the graphene oxide sheets and agglomeration of the nanoparticles are easily prevented. Additionally, the hybrid was such that it can be easily removed by magnetic separation process. Adsorption kinetics indicated 68 % removal efficiency for aqueous systems of 10 mg L−1 concentration, excellent adsorption capacity of ∼79 mg g−1, and initial adsorption rate of 5.7 mg g−1 min−1. Based on the various kinetic models, it was deduced that the process was boundary controlled at first, followed by surface diffusion controlled interparticle diffusion, and terminating of pore diffusion. Equilibrium isotherms indicated the adsorption to be spontaneous physisorption process, and chiefly monolayered with maximum adsorption capacity of 658 mg g−1, as per the Langmuir isotherm.