Synergetic, steric, and energetic properties of exfoliated kaolinite and its methanol hybridized structure during the adsorption of bisphenol-A residuals from the aqueous environment

Abstract

The adsorption potentiality of exfoliated kaolinite (EK) and its methanol hybridized product (MX.EK) for bisphenol-A (BSP-A) were assessed in synergetic studies to investigate the impact of the modification processes. The adsorption properties were illustrated based on the steric and energetic parameters of the applied advanced equilibrium modeling (monolayer model of one energy). The methanol hybridization process induced the adsorption properties of BSP-A significantly to 228.8 mg/g as compared to EK (160 mg/g) and raw kaolinite (K) (111.7 mg/g) during the saturation state. The steric investigation suggested a notable increase in the quantities of the active sites after the exfoliation process (Nm = 30.6 mg/g) and methanol functionalization (Nm = 49.2 mg/g) which illustrate enhancement in the BSP-A uptake capacity of MX.EK. Moreover, each active site of MX.EK can absorb about 8 molecules of BSP-A which occur in a vertical orientation. The energetic studies including Gaussian energy (˂ 8 KJ/mol) and adsorption energy (˂ 40 KJ/mol) demonstrate the physical uptake of BSP-A which might involve co-operated dipole bonding forces (2–29 kJ/mol) and hydrogen bonding (˂ 30 kJ/mol). The behaviors and values of entropy, intern energy, and free enthalpy as the assessed thermodynamic functions validate the exothermic and spontaneous properties of the BSP-A adsorption by EK and MX.EK composite.