Calculation of diffusion coefficient of doxycycline and naproxen adsorption on HKUST-1/ZnO/SA nanocomposite

Abstract

In recent years, water shortages and pollution of these finite resources have emerged as major worldwide problems. Pharmaceutical pollutants make up the largest percentage of all water pollutants. According to empirical evidence, the adsorption method was the most effective way to eliminate pharmaceutical pollutants from aquatic environments. The adsorption process was divided into three sections: Three diffusion and adsorption in adsorbent pores in the liquid bulk, and two mass transfer in the boundary layer. In the last step of adsorption, the mechanism of the adsorption process is formed by diffusion inside the adsorbent. Recently, there has been a lot of interest in modeling to solve mass transfer equations and estimate attributes, mostly because it is less expensive and riskier than experimental methods. In this study, the Langmuir kinetics model was used to match the D<inf>p</inf> of naproxen and doxycycline on the HKUST-1/ZnO/SA nanocomposite adsorbent, which was calculated using MATLAB. The desired data were also collected, and the case model was fitted using experimental data. Using the formulae and fitting the graphs, the modeling results show that the external film mass transfer coefficient (k<inf>f</inf>) and Langmuir second-order forward rate coefficient (k<inf>1</inf>) were comparable to 1.53 × 10−6 cm/s and 4.6 × 10−3 cm3/mg.s, respectively. Using the determined k<inf>1</inf> and k<inf>f</inf>, the D<inf>p</inf> of doxycycline was within the range of D<inf>p</inf> in solids and was 2.13 × 10−10 cm2/s. Given that the obtained k<inf>1</inf> and k<inf>f</inf> equaled 2.10 × 10−10 cm2/s, the D<inf>p</inf> of naproxen was within the range of D<inf>p</inf> in solids. Until it reached its maximum value on the adsorbent surface, the concentration rose in tandem with the radius. © 2025 Elsevier B.V., All rights reserved.