Deciphering the potent application of nanobentonite and α-Fe2O3/bentonite nanocomposite in dye removal: revisiting the insights of adsorption mechanism

Clays are widely accepted for dye removal from wastewater. Here, in this work, nanobentonite was synthesized by a simple, rapid, and cost-effective chemithermal method. Additionally, nanobentonite was coupled with hematite nanoparticles via thermal coupling to prepare a nanocomposite with enhanced surface absorption. Surface morphology, compositional and structural analysis of synthesized samples were done using various characterization techniques. Results suggested that nanobentonite and nanocomposite having an average diameter of 35.36 and 21.85 nm respectively were synthesized. Nanocomposite exhibited increased surface area. Additionally, the ability of all samples as an adsorbent for removal of methylene blue (MB) and Congo red (CR), from an aqueous solution was investigated under various optimization conditions. Adsorption kinetics revealed that Pseudo II order equation fits well for the adsorption process following intraparticular diffusion mechanism for both the dyes. The adsorption equilibrium data of MB and CR was fitted well by the Langmuir and Freundlich adsorption isotherm model, respectively. The thermodynamic parameters suggested adsorption process is endothermic and spontaneous in nature with increased entropy value.

Automated summary

Nanobentonite and its nanocomposite with hematite nanoparticles were synthesized by a chemothermal method, showing enhanced dye removal efficiency in wastewater treatment. Kinetic and equilibrium studies revealed that the adsorption process follows intraparticular diffusion mechanism and is well described by Pseudo II order equation, Langmuir and Freundlich adsorption isotherm models, indicating endothermic and spontaneous nature of the adsorption process.