Simultaneous Removal of Cationic and Anionic Dyes from Environmental Water Using Montmorillonite-Pillared Graphene Oxide

We investigate the removal of methyl orange (MO) and methylene blue (MB) from aqueous solution by montmorillonite-pillared graphene oxide (MGO). Experimental conditions were used that evaluate the potential of MGO in removing anionic and cationic dyes in single and binary systems, and we investigated the uptake capacity of MGO toward organic dye as a function of different pH, adsorbent dosage, temperature, and adsorption time. In the single system, the Langmuir and Freundlich adsorption models were used to describe the equilibrium isotherm and calculate the isotherm constants. Moreover, the pseudo-first-order and pseudo-second-order kinetic models were applied to study the mechanism of MGO adsorbing dyes. Thermodynamic studies demonstrated that the adsorption of MO and MB onto MGO was feasible and spontaneous. In the binary system, the adsorption capacities of MO and MB by MGO were dramatically higher than those in a single system. Therefore, through the recorded adsorption results under different conditions, we could illustrate that the MGO was absolutely used as an adsorbent to be capable of simultaneous removals of MO and MB.