Facile synthesis of a recyclable multifunctional magnetic adsorbent prepared from H2O2-modified carbon clay/rice flour polymer/Fe3O4 nanoparticles interface for effective removal of ibuprofen

Background: The combination between magnetite nanoparticles with natural carbohydrate polymers and aluminosilicates is recommended to be a positive strategy in the design of a new type of low-cost, high-efficiency, and eco-friendly magnetic adsorbents for decontamination of toxic pharmaceutical compounds from water. In particular, ibuprofen (IBP) is found to be one of the common drugs detected in water bodies, which is a suggestively alarming state.Methods: A fresh sample of gossan (iron-bearing weathered product) was used in the fabrication of magnetite nanoparticles (MNPs) to be used in the decoration of a bio-composite prepared from H2O2-activated black clay (BC) and biodegradable rice flour (RF) interface. The as-synthesized magnetic biosorbent (BC/RF/MNPs) was characterized by FTIR, FESEM, TEM, XRD, DSC, and TGA techniques and employed in the remediation of ibuprofen at pH 7.0 and temperatures of 25, 40, and 50 degrees C. The adsorption results were fitted to kinetics, traditional isotherms, and statistical physical models to better understand the interaction between IBP and BC/ RF/MNPs adsorbent.Significant finding: The pseudo-second-order (PSO) and Freundlich equations described the IBP adsorption system. Monolayer and double-layer advanced statistical physics models were employed to analyze the geometry and interactions mechanism at the molecular scale. The double-layer model showed the best-fitting results, and thus, its steric and energetic parameters and thermodynamic functions were explained. The number of the removed IBP molecules per site (steric n parameter) ranged from 0.55 to 0.84 suggesting the involvement of parallel and non-parallel orientations in the removal process. The adsorption capacity at saturation (Qsat) increased from 45.73 to 67.90mg/g at 25 - 50 oC signifying endothermic interactions. The adsorption energy ranged from 0.42 to 3.42kJ/mol reflecting the physical interactions between IBP and BC/RF/MNPs. Thermodynamic functions suggested the endothermic and spontaneous nature of the IBP adsorption process. Adsorption/desorption results suggested the high stability and economic benefit of BC/RF/MNPs sorbent.