1,4-Dioxane is an emerging contaminant that is completely miscible in water. It has been found extensively in groundwater, surface water, and wastewater effluents from wastewater treatment plants. Conventional water treatment technologies like carbon adsorption and air stripping are inefficient in removing this extremely mobile and persistent contaminant from water. Photocatalysis for pollutant degradation has been widely studied and is advantageous for contaminant degradation under mild conditions. In this study, two different types of metallic nanoparticles - titanium dioxide (TiO2) nanoparticles and nanoscale zero-valent iron (nZVI) were used and compared for the first time for removal of 1,4-dioxane under visible light. It was found that under visible light, both TiO2 nanoparticles and nZVI can completely remove 1,4-dioxane in a short period of time. Moreover, light intensity plays an important role in 1,4-dioxane degradation, the increase in which resulted in faster 1,4-dioxane degradation. Reactive oxygen species (ROS) were involved in both degradation processes, in addition, photogenerated holes h+ were critical for 1,4-dioxane degradation in TiO2/visible light system. TiO2/visible light system is more advantageous than nZVI/visible light system due to its capacity to degrade 1,4-dioxane at pH 7 compared to pH 3 using nZVI, and higher concentration of 1,4-dioxane can be degraded in a shorter time using TiO2. This study developed cost-effective solutions for removing 1,4-dioxane under visible light using two types of frequently used engineered nanomaterials; the methods can be applied for 1,4-dioxane degradation in contaminated environmental media.

Efficient 1,4-dioxane degradation under visible light by both titanium dioxide and zero-valent iron nanoparticles

ACS Fall 2021

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