Solvent-Free Production of Superhydrophobic TiO2 Nanoparticles and Their Photocatalysts Application


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Şakir M., Çelik N., Karagöz S., Yılmaz E., Önses M. S.

19TH Asian Chemical Congress, İstanbul, Turkey, 9 - 14 July 2023, pp.206-207

  • Publication Type: Conference Paper / Summary Text
  • City: İstanbul
  • Country: Turkey
  • Page Numbers: pp.206-207
  • Erciyes University Affiliated: Yes

Abstract

As industries grow, they produce more wastewater which harms the environment. Most of the wastewater is composed of water-soluble organic compounds, which are frequently used in industrial types such as food, textiles, medicine, and cosmetics. Photocatalytic degradation of organic compounds presents a solution to this issue. In conventional systems consisting of a liquid-solid interface, the absorption of light by the liquid phase causes photocatalytic materials to work less efficiently. Also, because O2 has a low solubility in water in two-phase systems, continuous O2 flow cannot be achieved. These results cause a serious decrease in photocatalytic efficiency. As a solution, floating superhydrophobic photocatalytic systems with air-liquid-solid interfaces are proposed. These systems allow for continuous O2 flow and direct exposure to UV light, improving photocatalytic efficiency. One way to create a superhydrophobic photocatalyst is by modifying the photocatalytic material with low surface energy binders. But these binders are expensive and hazardous, and they become hydrophilic when exposed to UV light. Polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE) are known to be relatively stable in photocatalytic activity. In PDMS or PTFE composite systems, photocatalytic activity decreases, although sufficient water repellency is provided, probably because a smaller fraction of the surface consists of photocatalytic material. In this case, the grafting of the PDMS directly onto the photocatalyst surface is a more attractive option. With a newly developed method, silicon was grafted onto the surface of the photocatalytic material using UV light. In this study, we present mechanochemical grafting of methyl-terminated PDMS (Me-PDMS) onto TiO2 nanoparticles in a solvent-free process. The effects of TiO2 nanoparticle sizes, Me-PDMS chain length, mixing time, mixing speed, and doping ratios on the system efficiency were investigated. In order to compare the floating threephase system and the two-phase system, pellets containing the same amount of superhydrophobic TiO2 nanoparticles were formed and their photocatalytic efficiency was compared. The fabricated superhydrophobic TiO2 nanoparticles were used for the photocatalytic degradation of methylene blue, an organic pollutant. Following the modification of 21 nm TiO2 nanoparticles with 100 cst of Me-PDMS, 10 ppm MB was 99% photo-catalytically destroyed after 120 minutes.

Keywords: TiO2, photocatalyst, Superhydrophobic