Application of nanoclay for the adsorptive removal of Orange G dye from aqueous solution

Montmorillonite nanoclay surface modified with octadecylamine (ODA nanoclay) was used to study the adsorptive removal of Orange G dye (OG dye) from model and real water samples. ODA nanoclay was characterized using different techniques and the results showed that ODA nanoclay has plate-like layered transparent structure, and the calculated BET specific surface area was found to be 16.38 m2 g− 1. Adsorption study showed that ODA nanoclay could remove most of the OG dye within few minutes, with adsorption capacity of 39.4 mg/g at ambient conditions. The results showed also that the interaction of the OG dye with the ODA nanoclay was electrostatic in nature and greatly depends on the pH of the solution. The adsorptive removal of OG dye on ODA nanoclay was explored kinetically and thermodynamically, and the results revealed the suitability of the pseudo-second-order kinetic model for describing the adsorption process compared with other kinetic model. Also, the adsorption process was spontaneous, endothermic in nature, and positive entropy change indicated the increase in the degree of freedom at the solid-liquid interface. The applicability of the ODA nanoclay for the adsorption of OG dye was explored using six different environmental water samples collected from different origin, and the results revealed the high efficiency of the proposed nanoclay.