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

Abstract

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°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.