To achieve sustainable water resources, new treatment technologies are needed that can be applied to a broad range of undesirable constituents in water over a broad range of water chemistries. In this project, nanomaterials were developed as building blocks for advanced treatment technologies through the controlled material synthesis technique of electrospinning. Electrospun nanofibers are promising materials for nano-integrated systems due to their simple tuning and production, large surface-area-to-volume ratio, and potential substrate integration to prevent incidental release into the environment.
In this work, electrospun metal oxide nanofibers were synthesized and optimized for their application in various aspects of water treatment, which include Ag-enriched TiO2 nanofibers for UV-driven photocatalytic oxidation of organic microcontaminants, Al2O3-Fe2O3 composite nanofibers for adsorption of heavy metals, and BiVO4 nanofibers for visible light-activated photocatalytic oxidation.
TiO2 nanofibers were developed and tuned to alter morphological, dimensional and optical properties towards optimal photocatalytic performance of contaminant degradation. Electrospinning synthesis yielded nanofibers with controlled diameter, crystal phase, grain size, and band gap. Photoreactivity studies towards the model pollutant phenol showed that diameter and crystal phase composition were the two major factors in optimizing TiO2 nanofibers performance. Additionally, the introduction of Ag led to further enhancement of photoreactivity, where optimization of the composite nanofibers was tied predominantly to Ag content.
Fe2O3 nanofibers were developed and tuned to alter morphological and dimensional properties towards optimal adsorption of heavy metals. Electrospinning synthesis yielded nanofibers with controlled diameter, crystal phase, grain size, and specific surface area. Chromate adsorption isotherm studies reveal increased sorption capacity with decreased diameter of the Fe2O3 nanofibers, attributed with the increased surface area. With the addition of Al, Al2O3-Fe2O3 composite nanofibers were produced with even greater sorption capacity due to further enhanced surface area.
BiVO4 nanofibers were developed and tuned to control morphological, dimensional and optical properties towards optimal visible-light activated photocatalytic performance. Electrospinning synthesis yielded nanofibers with controlled diameter, crystal phase, grain size, and band gap. Photoreactivity studies towards phenol showed that reactivity increased with decreased nanofiber diameter. The addition of Ag and Au co-catalysts enhanced photoreactivity of the BiVO4 nanofibers, outperforming TiO2 nanomaterials under visible light irradiation.