Albert Sacco Jr.
Fabrizio Lombardi, Elizabeth J. Podlaha-Murphy
Date of Award
Master of Science
Department or Academic Unit
College of Engineering. Department of Chemical Engineering.
chemical engineering, nanotechnology, colloidal anatase, Engelhard Titanosilicate, ETS-10, Nano anatase, Titanium Dioxide, zeolite
Textile fabrics, Titanium dioxide crystals
Mechanics of Materials | Polymer and Organic Materials
Functionalized textiles present a vast and growing niche in the global textile market at US $400 billion [1, 2]. Engelhard Titanium Silicate 10 (ETS-10), a photocatalytic zeo-type material if coated on textiles, is expected to impart useful properties similar to TiO2, such as stain-resistant, odor repellant, bactericidal and enhanced UV protection [3, 4]. Typically, small ETS-10 crystals of size ~300-800 nm are synthesized using solid titania (e.g., anatase or P25) sources [5, 6, 7]. However, smaller ETS-10 crystals are required for a uniform surface coating with highly effective surface area. The dissolution of titania particles (i.e., their size) is hypothesized to be important in small ETS-10 crystal formation [5, 6, 7]. Nano anatase was synthesized by modification of two methods: direct precipitation  and sol-gel synthesis . Analysis by XRD confirmed that both methods produced nano anatase of crystallite size ~4-5 nm. However, FE-SEM analysis showed that product from direct precipitation, existed as intergrown spheroidal particles with size ~1.0 μm. These particles dispersed poorly in deionized water. Therefore, the best nano anatase samples were from sol-gel synthesis in two forms, dry powder and colloidal anatase.
ETS-10 synthesis was investigated using two methods adopted from literature [6, 7]. The method of Yoon and co-workers , with nano anatase in a molar composition of 5.5TEOS: TiO2: 8.4NaOH: 1.43KF: 350H2O:2.2H2SO2 produced unknown phase(s) with some ETS-10 and quartz. Using colloidal anatase with molar composition 5.5TEOS:1.0TiO2:8.4NaOH:1.43KF:400H2O:2.2H2SO2 also produced unknown phase(s). The method of Anderson and co-workers  with nano anatase powder in a molar composition of 5.5SiO2: TiO2: 5.2Na2O: 0.5K2O: 113H2O produced quartz with ETS-10 impurity. When colloidal anatase was used, with molar composition TiO2:5.5SiO2:5.2Na2O:0.5K2O:332H2O, unreacted anatase and quartz were formed. It was hypothesized that the very low reaction mixture pH of ~4.1 was responsible for the absence of ETS-10. Therefore, pH of this mixture was modified between ~6.55-12.75.At low pH of ~6.55 unreacted anatase was present, while, pH higher than ~11.24 formed ETS-4 crystals. At an &Idquo;optimum” pH of ~11.24 nearly phase-pure ETS-10 crystals were formed. However, these ETS-10 crystals were not small but ~10-20 μm. This is the first time, that colloidal anatase has been utilized for ETS-10 synthesis.
Shafeque, Shihara, "Synthesis of nano anatase for titanosilicate ETS-10 synthesis" (2009). Chemical Engineering Master's Theses. Paper 9. http://hdl.handle.net/2047/d20000820
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