Experimental investigation of competitive co-adsorption of naproxen and diclofenac from water by an aluminum-based metal-organic framework

Abstract

Commercially available Aluminum-benzenedicarboxylate (Basolite A100, MIL-53 (Al)), Metal-Organic Framework was successfully used for the adsorption and co-adsorption of Naproxen (NAP) and Diclofenac (DCF) from aqueous solutions. The adsorption experiments were carried out using single-component NAP/DCF and their binary aqueous solutions. The experimental results demonstrated the remarkable removal efficiency of the MOF (>96% for NAP and >99% for DCF). Besides, the competitive adsorption of the drugs from binary solutions showed higher selectivity toward DCF. The hydrogen bonding and π-π stacking were investigated to gain insight into the adsorption mechanism. The pH effect experiments in the range of 2 to 8 showed that as pH increased, the adsorption capacity of both drugs decreased. The fitting of the adsorption isotherm and kinetic models confirms that both contaminants conform to the Langmuir model and pseudo-second-order (PSO) models with high regression coefficient ( R 2 > 0.99). The PSO rate constant values for NAP were 0.0056 (single-component) and 0.0024 g·mg −1 ·min −1 (binary), while for DCF these values were 0.0037 (single-component) and 0.0014 g·mg −1 ·min −1 (binary). According to the isotherm model, the calculated maximum removal capacities ( q m ) values were found equal to 297 and 422 mg/g for NAP and DCF, respectively. The suitability of MIL-53(Al) for adsorption of naproxen and diclofenac in mineral water was also investigated. Finally, MIL-53(Al) was confirmed to be a promising adsorbent candidate thanks to its highly efficient removal of NAP and DCF in both single and binary solutions and then can be deployed in water treatment. • MIL-53(Al) showed great potential for water purification from pharmaceuticals. • MIL-53(Al) had better selectivity for DCF compared to NAP. • Adsorption mechanism was determined to be due to hydrogen bonding and π-π stacking. • The experimental data fitted best the Langmuir isotherm and PSO kinetic models. • The maximum adsorption capacities' values were found equal to 297 and 422 mg/g for NAP and DCF, respectively.