Application of magnesium peroxide (MgO2) nanoparticles for toluene remediation from groundwater: batch and column studies.

In the present study, magnesium peroxide (MgO2) nanoparticles were synthesized by electro-deposition process and characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The batch experiments were conducted to evaluate the MgO2 half-life (600 mg/L) in groundwater under various temperatures (4, 15, and 30 °C) and initial pH (3, 7, and 12). The effect of Fe2+ ions (enhanced oxidation) on the toluene remediation by MgO2 was also investigated. Nanoparticles were injected to sand-packed continuous-flow columns, and toluene removal (50 ppm) was studied within 50 days at 15 °C. The results indicated that the half-life of MgO2 at pH 3 and 12 were 5 and 15 days, respectively, in comparison to 10 days at the initial pH 7 and 15 °C. The nanoparticles showed 20 and 7.5 days half-life at 4 and 30 °C temperatures, respectively. Injection of Fe2+ ions indicated an impressive effect on toluene removal by MgO2, and the contaminant was completely removed after 5 and 10 days, in the batch and column experiments, respectively. Confocal laser scanning microscope (CLSM) analysis indicated that the attached biofilm had a significant role in the decontamination of groundwater. Comparison of bioremediation and enhanced oxidation resulted in a considerable insight into the application of magnesium peroxide in groundwater remediation. Graphical abstract ᅟ.