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

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 x 10(-9) to 9.52 x 10(-9) cm(2)/s for acetaminophen, from 1.87 x 10(-9) to 8.21 x 10(-9) cm2/s for ibuprofen, and from 1.15 x 10(-9) to 1.65 x 10(-9) cm(2)/s for ketoprofen.

Automated summary

The 3D-PVSDM model was used to predict adsorption of acetaminophen, ketoprofen, and ibuprofen in a ZnAl/biochar composite, showing that surface diffusion flux was the primary transport mechanism. Therefore, pore volume diffusion could be neglected, and a simplified 3D-SDM model could accurately simulate the mass transport.