Date of Award
Master of Science
1,4-dioxane is an emerging contaminant and fully miscible organic compound which has been found extensively in wastewater effluent. Conventional water treatment technologies like carbon adsorption, and air stripping are inefficient in removing this extremely mobile and persistent contaminant from water. In this study, different types of metallic nanoparticles, e.g., nanoscale zero-valent iron (nZVI), γFe2O3, and Fe(III)-doped TiO2 were used to investigate the removal of 1,4-dioxane under visible light. These nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM) and dynamic light scattering (DLS). The experiments were first carried out using deionized water (DIW) at pH 7 and pH 3. nZVI was found more efficient than other nanoparticles under visible light irradiation at pH 3. No 1,4-dioxane removal was obtained for all cases at pH 7 under visible light, or at pH 3 in dark. Moreover, light intensity also plays a significant role in 1,4-dioxane removal. Removal of 22.3%, 40.0% and >99.9% of 1.4-dioxane was reached under 2.4 mW/cm2, 2.6 mw/cm2 and 3.25 mW/cm2 light intensities, respectively, after 6 h of irradiation. The most efficient nanoparticle nZVI was applied to wastewater effluent from Carbondale Southeast Wastewater Treatment Plant. From the results, it was found that 1,4-dioxane degradation took longer time in wastewater effluent than in DIW, because of the presence of other constituents in the wastewater sample. nZVI is also capable of removing 1,4-dioxane in presence of trichloroethylene (TCE) and tetrachloroethylene (PCE) at pH 3 under visible light. In comparison, TiO2 nanoparticle is capable of degrading 1,4-dioxane under visible light or under sunlight at pH 7. Moreover, TiO2 removed 1,4-dioxane in presence of both TCE and PCE at pH 7 under visible light or sunlight. This study found a cost-effective and efficient solution for removing 1,4-dioxane from wastewater effluent that can be reused, by using metallic nanoparticles under visible light.
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