Residue-based TiO2/PET photocatalytic films for the degradation of textile dyes: A step in the development of green monolith reactors

• Published in: Chemical engineering and processing 2020-01, Vol.147, p.107792, Article 107792
• Main Authors: Ribeiro, Lívia N., Fonseca, Aline C.S., da Silva, Emerson F.M., Oliveira, Evelle D.C., Ribeiro, André T.S., Maranhão, Laisse C.A., Pacheco, Jose G.A., Machado, Giovanna, Almeida, Luciano C.
• Format: Article
• Language: English
• Subjects: Immobilization of TiO2; PET bottle; PET monolith; RB5
• ISSN: 0255-2701; 1873-3204
• DOI: 10.1016/j.cep.2019.107792

[Display omitted] •Monolithic systems are a promising technology for textile dye degradation.•The PVA increased the visible light absorption, leading to greater dye degradation.•The films showed homogeneous overlay and good stability after 5 cycles of use.•Total organic carbon (TOC) conversion increases with increasing irradiated area. A batch-process with a dispersed solid photocatalyst requires a large reactor and unit process for catalyst recovery, increasing the treatment cost. Structured-supported photocatalysts enable the use of continuous compact reactors that are photoactivated by solar energy and promote process intensification. In the present work, TiO2-films supported on polyethylene terephthalate (TiO2/PET) in sheets and monolithic shapes were prepared from reused PET-bottles. The preparation method was based on a washcoating of a TiO2 suspension with different formulations (additives and loaded photocatalyst) aiming at proper adherence. The use of polyvinyl alcohol (PVA) as an additive in the TiO2 dispersion was assessed to obtain a homogeneous coating. The effects of sheets and monolith dimensions, as well as the mass of deposited TiO2 over the PET-substrate, on the dye degradation performance were studied. The TiO2/PET sheets and monoliths showed homogeneous overlay and good stability after 5 cycles of use. The TiO2/PET monolith showed a degradation of approximately 30 % and 75 % for the initial dye concentrations of 25 and 15 mg L−1, respectively. The monolith-type immobilized systems proved to be a promising technology due to their low cost and low use of reactants and catalysts. Furthermore, this type of system is more promising for continuous processes.