Magnetically enhanced mesoporous silicate as an efficient adsorbent for the removal of phenoxy acid herbicide from aqueous solutions

Abstract

Superparamagnetic Fe3O4-MCM-41 was successfully synthesized using direct hydrothermal route and was utilized as an excellent adsorbent for the removal of 2,4-dichlorophenoxyacetic acid herbicide from aqueous solution. The superparamagnetic mesoporous adsorbent was fully characterized using XRD, FE-SEM, EDS, N2 sorption, and VSM. Synthesized adsorbent exhibited a high specific surface area of 444 m2.g−1, making it a suitable candidate for adsorption purposes where it provides higher adsorption capacity. Based on the VSM study, the recorded saturated magnetization was 15.9 emu.g−1 which confirms the viability of the adsorbent to be easily separable from an aqueous media by a magnet. The ability of Fe3O4-MCM-41 as an adsorbent of 2,4-dichlorophenoxyacetic acid herbicide from water was tested considering various parameters such as pH, adsorbent dosage, contact time, and pollutant concentration. The effectiveness of Fe3O4-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 at the optimum condition was 94.8%. Based on the experimental data and kinetic studies, adsorption process followed the pseudo-second ordered kinetic and Langmuir isotherm.