Adsorption equilibrium, kinetic, and thermodynamic studies on the removal of paracetamol from wastewater using natural and HDTMA-modified clay

Abstract

In this study, the adsorption efficiency of low-cost raw and modified clay was investigated. The modified clay was characterized through various technics including X-ray diffraction, XRF spectroscopy, FT-IR spectroscopy, and Electron microscopy SEM to analyze the evolution of raw clay structure and morphology. Paracetamol was chosen as an adsorbate to evaluate the removal performance from the aqueous medium. Factors influencing the uptake of paracetamol, such as pH, equilibrium time, adsorbent dosage, and initial concentration of paracetamol, were examined. The results obtained showed that the raw clay was successfully modified by HDTMA, which increased adsorption capacity thanks to new hydrophobic interaction. The adsorption of paracetamol on the modified clay reached equilibrium at a contact time of 120 min. Isothermal and kinetic models used in this study showed that the adsorption followed the Langmuir-isotherm and pseudo-second-order kinetic models. The maximum experimental adsorption capacity predicted by Langmuir model is about 112.63 mg/g, which is much higher than that obtained for the unmodified sample (62.11 mg/g). These results show that modified natural Moroccan clay can be used as low-cost and eco-friendly adsorbent nanomaterials to remove emerging pharmaceutical contaminants from water.