Investigating the sequestration potential of a novel biopolymer-modified ceria/montmorillonite nanocomposite for chromium and coomassie brilliant blue from the aqueous phase: equilibrium and kinetic studies

Abstract

This study involves the fabrication of a novel, sustainable, and economically viable adsorbent ceria/rice flour/montmorillonite nanocomposite (Ce-R-MMT) for the decontamination of Cr(VI) and coomassie brilliant blue (CBB) from the aquatic phase. The structural characteristics and sorption interaction was elucidated via X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and transmission electron microscopy (TEM). The sorption behavior was strategized systematically via batch experiments, which include adsorbent dosage, contact time, initial CBB concentration and initial solution pH, equilibrium, and kinetic curves. The Freundlich model best illustrated the equilibrium data implying the multilayer adsorption of CBB and Cr(VI) onto the heterogeneous surface of the prepared nanocomposite. Pseudo-second order appropriated the kinetics of the process. Diffusion modelling suggested that intraparticle and liquid film diffusion models cooperatively governed the diffusion of probed pollutants. Thermodynamic parameters implied the adsorption process to be feasible and exothermic. The binary study showed an antagonistic effect as R value was <1. Electrostatic interaction was responsible for the uptake of both pollutants by the nanocomposite. The sequestration potentiality assured by sorption capacity for CBB (713.513 mg g⁻¹) and Cr(VI) (182.037 mg g⁻¹) and regeneration ability up to 3 consecutive adsorption–desorption cycles conferred Ce-R-MMT to be a promising sorbent for the sequestration of CBB and Cr(VI).