Efficient removal of Ibuprofen via novel core – shell magnetic bio-surfactant rhamnolipid – layered double hydroxide nanocomposite

Abstract

A novel core-shell magnetic rhamnolipid (MRL) – Co/Al layered double hydroxide (LDH) nanocomposite was prepared through delaminating magnetic LDH and RL/NaOH assembling water solution for the elimination of ibuprofen (IBP) from wastewater. The characterization of MRL– Co/Al LDH nanocomposite was performed by FT-IR, XRD, TEM, VSM, and SEM. The results confirmed that MRL – Co/Al LDH particles were formed by Fe3O4 core and RL–LDH structures as shell, and RL− anions were successfully intercalated into interlayers of magnetic Co/Al LDH. The adsorption of IBP by MRL– Co/Al LDH from wastewater was examined by applying an external magnetic field for the separation. It was found that the process was excellent at initial pH solution 5, contact time 120 min, IBP concentration 80 mg/L, and adsorbent dosage 0.01 g. The obtained results indicated that the adsorption capability of MRL – Co/Al LDH for IBP was 200.09mg/g based on Langmuir isotherm (R2 0.9893). The examination of kinetic data exhibited that the adsorption of IBP onto LDH was according to the pseudo-second-order (R2 0.9996) assumptions, and the process was naturally exothermic (ΔHº −24.96 kJ mol−1). By increasing the temperature from 25 to 55 ºC, the adsorption capacity reduced from 110 to 78 mg/g, respectively. Also it was indicated that even after 4 successive usage of the adsorbent, its adsorption capacity was greater than 180 mg/g. Physical adsorption, electrostatic attraction, hydrogen bonding and anion exchange are the involved mechanisms in IBP removal. The present research demonstrated that core-shell magnetic rhamnolipid – Co/Al layered double hydroxide nanocomposite is a promising adsorbent for IBP elimination from solutions.