Open-cell ceramic foams covered with TiO2 for the photocatalytic treatment of agro-industrial wastewaters containing imazalil at semi-pilot scale

• Published in: Journal of the Taiwan Institute of Chemical Engineers Vol. 147; p. 104902
• Main Authors: Martín-González, M.A., Fernández-Rodríguez, C., González-Díaz, O.M., Susial, P., Doña-Rodríguez, J.M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2023
• Subjects: Imazalil removal; Open-cell ceramic foams; Solar photocatalysis; TiO2 coatings; Open-cell ceramic foams; Solar photocatalysis; Imazalil removal; TiO2 coatings
• ISSN: 1876-1070; 1876-1089
• DOI: 10.1016/j.jtice.2023.104902

•0pen-cell ceramic foams were characterized and compared as TiO2 supports.•C-free support led to a higher specific degradation/mineralization of Imazalil.•Imazalil degradation and mineralization was achieved at a semi-pilot scale.•Less than 10 KJ L−1 were necessary to eliminate the toxicity of the effluent.•The technique could be easily adapted to the characteristics of the wastewater.
Imazalil is a fungicide widely used in postharvest agroindustry, which causes a negative impact on the environment. To remove it from agro-industrial wastewaters, solar heterogeneous photocatalysis, with the photocatalyst fixed onto support, constitutes a promising technique. In this work, two open-cell ceramic foams (with and without carbon) were evaluated as TiO2 supports. Technical and economic feasibility of photocatalysis with TiO2 supported on ceramic foams were assessed.
Foams were covered with TiO2 by dip-coating and subsequent calcination. The obtained systems were characterized by different techniques. Lab-scale removal of imazalil in pure and real water matrices was studied for both materials. The highest performance system was also evaluated at semi-pilot scale.
The C-free support led to the highest photoactivity in both water matrices at lab-scale. No TiO2C synergistic effect was observed due to photon absorption phenomena detected for the support with graphite. The C-free foams coated with TiO2 can be used in solar reactors to decontaminate wastewater with imazalil, achieving 95% degradation and a nontoxic condition for Allivibrio fischeri bacteria at accumulated energy values less than 10 kJ·L−1. This technique can be adapted to each real situation through the adequate selection of the number of photocatalytic converters exposed to sunlight. After economic evaluation, the experimental technology could be considered cost-effective.
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