Remediation of ibuprofen and naproxen in water by a green composite material of magnetic carbon nanotube–metal–organic framework

Abstract

This work adopted a simple and green method for synthesizing a composite of magnetic carboxylic multi–walled carbon nanotube–metal–organic frame (MCNTs–UiO–66–NH2) at room temperature, which was applied to the remediation of ibuprofen (Ibu) and naproxen (Nap) in wastewater. The influencing factors of adsorption were investigated, including adsorbent dosage, pH value, coexisting ions, temperature, and contact time, etc. Various methods were employed for analyzing the structural features and surface characteristics exhibited by MCNTs–UiO–66–NH2. The values of max adsorption quantity about MCNTs–UiO–66–NH2 toward Ibu and Nap reached 143 mg·g–1 and 139 mg·g–1 at 313 K, respectively. The Langmuir model and Pseudo–second–order model can describe the adsorption process of Ibu and Nap. According to the values of the thermodynamic parameters, both adsorption processes were endothermic, spontaneous and could lead to an increase in entropy. In addition, the composite can be used to capture Ibu and Nap in the pH range of 1–10 and the salinity range of 0–0.2 mol·L–1 with an ideal regeneration performance taking 5 mmol·L–1 NaHCO3 as eluent. The mechanism of adsorption is including complexation, π–π conjugation, electrostatic action and H–bonding. These properties confirm MCNTs–UiO–66–NH2 as one potential adsorbent for remediation of Ibu and Nap in wastewater.