Copper(II) isonicotinate metal-organic framework for reusable adsorption of salmeterol from wastewater

Abstract

This study investigates the adsorption of salmeterol (SMT) from aqueous solutions using a novel nano-sized copper-based metal-organic framework (Cu-MOF). The Cu-MOF was synthesized under solvent-free conditions, enhancing its environmental sustainability. Key parameters such as adsorbent dosage, initial SMT concentration, temperature, and pH were systematically evaluated to optimize adsorption performance. The results demonstrate the exceptional adsorption capacity of the Cu-MOF, reaching a maximum of 400 mg/g within 50 minutes of contact time under optimal conditions of 4 mg Cu-MOF, 50 mg/L SMT, and pH 11. The kinetic and isotherm studies revealed that the pseudo-second-order and Langmuir models exhibited superior fitting to the experimental data, as evidenced by their exceptional R² values of 0.999 and 0.999, minimal RMSE values of 0.034 and 0.001, and significantly lower AIC values of −45.77 and −129.17 for the kinetic and isotherm models, respectively. Thermodynamic analysis confirmed the exothermic and spontaneous nature of the adsorption process. Moreover, the Cu-MOF exhibited excellent reusability, maintaining its adsorption efficiency over six consecutive cycles. Therefore, these findings highlight the potential of Cu-MOF as a promising and sustainable adsorbent for effectively removing salmeterol from wastewater.