Ibuprofen removal by modified natural zeolite: characterization, modeling, and adsorption mechanisms

Abstract

BACKGROUND

Developing robust technologies to remove emerging pollutants from water is urgent since conventional treatments are not technically prepared to remove them. This paper investigated the ibuprofen (IBU) adsorption capacity onto natural zeolite (NZ) and hydrothermally modified zeolite in an acidic medium followed by impregnation with the cationic surfactant cetyltrimethylammonium bromide (CTAB) (MZ_HT-CTAB). The materials characterization included scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic absorption spectroscopy (AAS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTG), N₂ adsorption/desorption isotherm (BET), Zeta Potential (ZP), and Point of Zero Charge (pH_PZC). The adsorptive capacity studies were carried out by varying the pH solution, a kinetic study at three concentrations (25, 50, and 100 mg L⁻¹), and the contaminant concentration influence (5–100 mg L⁻¹).

RESULTS

The results showed that the MZ_HT-CTAB obtained both the highest removal efficiency (~ 37%) and the highest adsorption capacity (~ 14 mg g⁻¹) at pH 5.0. The Pseudo Second-Order (PSO) model, which showed the best fit to the experimental data, is significant as it indicates the reliability of our results. The maximum adsorption capacity for the concentration of 100 mg L⁻¹ was 11.93 mg g⁻¹. According to Giles's classification, the isotherm was classified as S-3 type, indicating the competition between the adsorbate and water molecules for the active sites on the adsorbent surface.

CONCLUSION

The adsorption studies demonstrate that the novel adsorbent (MZ_HT-CTAB) is highly effective in removing IBU, presenting a significant removal capacity and feasibility. This promising result contributes to the ongoing search for alternative materials for water treatment. © 2024 Society of Chemical Industry (SCI).