Three-dimensional mass transport modeling of pharmaceuticals adsorption inside ZnAl/biochar composite

Abstract

Three-dimensional Pore Volume and Surface Diffusion Model (3D-PVSDM) was implemented to predict the adsorption of acetaminophen, ketoprofen, and ibuprofen inside ZnAl/biochar composite. The experimental results revealed that ZnAl/biochar composite presented a remarkable potential as adsorbent in the studied adsorption systems since the maximum adsorption capacity was 1,108.43 mg/g for acetaminophen, 1,081.35 mg/g for ketoprofen, and 1,032.81 mg/g for ibuprofen. The equilibrium adsorption of acetaminophen was well fitted by Freundlich isotherm, while Henry isotherm properly adjusted the equilibrium adsorption of ketoprofen and ibuprofen. The 3D-PVSDM simulations indicated that the surface diffusion flux was the priority transport mechanism during the adsorption of acetaminophen, ketoprofen, and ibuprofen onto ZnAl/biochar composite. Therefore, it was possible to neglect the pore volume diffusion and apply the simplified three-dimensional Surface Diffusion Model (3D-SDM) to accurately simulate the mass transport of pharmaceutical compounds on ZnAl/biochar composite. The surface diffusion coefficients ranged from 2.58 × 10−9 to 9.52 × 10−9 cm²/s for acetaminophen, from 1.87 × 10−9 to 8.21 × 10-9 cm²/s for ibuprofen, and from 1.15 × 10-9 to 1.65 × 10−9 cm²/s for ketoprofen.