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Doctoral Dissertation Announcement
Candidate: Seonghyuk Ko
Doctor of Philosophy
Department: Paper Engineering, Chemical Engineering, and Imaging
Title: Zeolite-Based Nanosized TiO2 Photocatalytic Paper for Antimicrobial Barrier and Toxin Passivation in Packaging: Design, Synthesis and Characterization
Dr. Paul D. Fleming, Chair
Dr. Margaret K. Joyce
Dr. Pnina Ari-Gur
Date: Tuesday, July 1, 2008 10:00 a.m. – 12:00 p.m.
Room A-213, Parkview Campus
This dissertation describes comprehensive studies, including design, preparation, characterization, and evaluation, to develop an innovative zeolite-based nanosized TiO2 photocatalytic paper for disinfection and disintegration of organic toxins.
A novel paper with high photocatalytic performance was successfully prepared using natural zeolite (clinoptilolite)-based nanosized TiO2 photocatalyst in a microparticle retention papermaking system. Photocatalytic material, from its sol-gel derived TiO2 colloids to its anchoring onto zeolite, has been designed, prepared, and characterized. Prior to photocatalytic papermaking, the characteristics of sol-gel synthesized TiO2 nanoparticles from colloidal to nanopowder were investigated with various initial sizes of colloidal nanoparticles synthesized in the range of 2.5±0.1 nm and 14.3±0.9 nm. The resulting pre-matured anatase TiO2 on zeolite particles were also readily used in photocatalytic paper, which revealed zeolite-TiO2 particles well-dispersed on a dense network of fibers. The fractions between two crystalline phases of TiO2 nanoparticles were subsequently specified so as to ensure high optical properties and photoactivity as well, and consequently, the optimum value of phase ratio was in the proportion of 0.48 rutile to 0.52 anatase and 0.71 rutile to 0.29 anatase.
In preparation of photocatalytic paper, natural zeolite is evidently confirmed as the most significant and interactive factor for increasing the TiO2 retention rate by applying a factorial experimental design. It was revealed that natural zeolite plays an important role in both increasing the retention rate of TiO2 nanoparticles and enhancing photocatalytic efficiency of the paper. The zeolite-based TiO2 photocatalytic paper presented here decomposed gaseous toluene very effectively under UV irradiation and the removal efficiency was better than that of a comparison group including Degussa P25 TiO2 paper and commercially available photocatalytic paper. It is indeed clear that these outstanding findings provide a strong likelihood of additional applications, such as innovative photocatalytic paper being used for environmental purification and antimicrobial passivation.