The need for water filtration is an ever growing problem underdeveloped countries and will be a major stressor on modern economies in the future. The need for clean water has led to a push for new methods of decontamination methods. We explore two methods being developed at Clemson University. First is nanotitanium infused cellulose acetate fiber membranes and the second is nanocellulose fiber/crystal composite membranes.

Nanotitania photocatalysis using ultraviolet radiation (TiO2/UV process) is an alternative method to conventional water treatment processes that can completely degrade organic contaminants into harmless substances, such as carbon dioxide and water, under moderate conditions. This contribution describes the development of a photocatalytic nanofiber-TiO2 composite membrane for the removal of organic contaminants in water. The objectives of this study were to determine the maximum amount of TiO2 nanoparticle loading that could be achieved and measure photocatalytic removal of organic contaminants. Cellulose acetate (CA)-TiO2 composite membranes were prepared via electrospinning by dispersing TiO2 nanoparticles in the CA casting solution. TiO2 nanoparticles were added into the casting solution at concentrations that varied from 0 to 4.8 wt.%. Optical microscopy was used for fiber characterization. Scanning electron microscopy (SEM) was performed to measure particle distribution. Measurements of pure water permeability and removal of humic acid by photocatalysis using TiO2 nanoparticle loaded membranes and control membranes containing no particles were used to test membrane performance. The maximum amount of titania nanoparticle loading that could be achieved was 4.8 wt.%. Pure water permeability did not change within the measurement uncertainty with the addition of a thin nanofiber-TiO2 mat to a 0.45 µm regenerated cellulose membrane.

Nanocellulose fiber/crystal composites use cellulose as a basis for adding functional groups to remove specific contaminants. This novel method of membrane creation delivers high flux without significant sacrifice in selectivity. Furthermore the membrane is made from readily available chemicals and natural components, making it more economically viable. An electrospinning apparatus was used to spin cellulose acetate nanofibers onto a commercial regenerated cellulose microfilitration membrane support. This combination is then augmented by loading cellulose nanocrystals into it, further increasing the surface area for selective functional groups. A comparative experiment was done to determine the drop in flux with each additional layer. Initial results indirectly indicate loading of the nanocrystals into the nanofiber support composite. The flux measurements drop slightly as expected, with further testing needed to verify the proper level of filtration.