Affiliation:
1. Analytical Chemistry student, Department of Chemistry, Islamic Azad University, Ahvaz Branch, Ahvaz, Iran
2. Associate Professor, Department of Chemistry, Islamic Azad University, Ahvaz Branch, Ahvaz, Iran
Abstract
Superparamagnetic iron (II,III) oxide (Fe3O4)–MCM-41 was successfully synthesised using a direct hydrothermal route and was utilised as an excellent adsorbent for the removal of the herbicide 2,4-dichlorophenoxyacetic acid from aqueous solution. The superparamagnetic mesoporous adsorbent was fully characterised using X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, nitrogen (N2) sorption and vibrating-sample magnetometry (VSM). The synthesised adsorbent exhibited a high specific surface area of 444 m2/g, making it a suitable candidate for adsorption, where it provided a higher adsorption capacity. Based on the VSM study, the recorded saturated magnetisation was 15.9 emu/g, which confirmed the viability of easily separating the adsorbent from an aqueous medium using a magnet. The ability of iron (II,III) oxide–MCM-41 to adsorb the herbicide 2,4-dichlorophenoxyacetic acid from water was tested considering various parameters, such as pH, adsorbent dosage, contact time and pollutant concentration. The effectiveness of iron (II,III) oxide–MCM-41 in removing the herbicide reached its highest peak at pH = 5, 0.05 g adsorbent, 60 min contact time and 10 mg/l 2,4-dichlorophenoxyacetic acid. The maximum removal efficiency under optimum conditions was 94.8%. Based on the experimental data and kinetic studies, the adsorption process followed a pseudo-second-order kinetic and Langmuir isotherm model.