Argamassa autolimpante por meio da aspersão superficial de dióxido de titânio
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Data
2022-11-21
Autores
Otuka, Pedro Henrique
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Universidade Estadual Paulista (Unesp)
Resumo
A deposição de partículas na superfície das fachadas das edificações ao longo de sua vida útil acarreta a perda do desempenho de seus materiais constituintes além do prejuízo estético causado por manchas, acarretando a desvalorização do imóvel e custos com manutenção e limpeza. Técnicas, mecanismos e materiais que busquem amenizar tais efeitos se tornaram assunto amplamente estudado na área de ciência de materiais. Dentre as técnicas, os processos oxidativos avançados se destacam, pois possibilitam a degradação de poluentes por meio de fotocatálise ao empregar materiais semicondutores consagrados como, por exemplo, o dióxido de titânio (TiO2). A aplicação desse semicondutor possui lugar de destaque devido às suas características químicas e físicas. No presente trabalho, foi utilizado o TiO2 P25 como material fotocatalisador, para conferir propriedades autolimpantes à argamassa de cimento branco. Também foi comprovada a capacidade de degradação do corante rodamina-B em solução aquosa sob radiação ultravioleta artificial e radiação solar. O ensaio de difratometria de raios-X indicou que o TiO2 P25 utilizado é composto de 13,77% de fase rutilo e de 86,23% de anatase. As aspersões superficiais de TiO2 P25, na superfície da argamassa, se mostraram eficientes na degradação de rodamina-B em solução aquosa. Sob radiação UV, a degradação da rodamina-B para o corpo de prova sem TiO2 e com 0,100 g de TiO2 foi de 22,8% e 93,5%, respectivamente. A degradação da rodamina-B sob radiação solar foi de 9,3% sem TiO2, e de 99,5% com 8,2 g de TiO2 aspergidos superficialmente. O efeito autolimpante foi observado em todas as aspersões de TiO2 propostas, inclusive para as argamassas de menor concentração de TiO2 em sua superfície.
The deposition of particles on the surface of the facades of buildings throughout their useful life leads to the loss of performance of their constituent materials in addition to the aesthetic damage caused by stains, leading to the devaluation of the property and costs with maintenance and cleaning. Techniques, mechanisms and materials that seek to mitigate such effects have become a subject widely studied in the area of materials science. Among the techniques, advanced oxidative processes stand out, as they allow the degradation of pollutants through photocatalysis when using established semiconductor materials such as titanium dioxide (TiO2). The application of this semiconductor has a prominent place due to its chemical and physical characteristics. In this work, TiO2 P25 was used as a photocatalyst material to impart self-cleaning properties to the white cement mortar. It was also proven the ability of rhodamine-B to degrade in aqueous solution under artificial ultraviolet radiation and solar radiation. The X-ray diffractometry test indicated that the TiO2 P25 used is composed of 13.77% of rutile phase and 86.23% of anatase. The superficial sprays of TiO2 P25, on the surface of the mortar, proved to be efficient in the degradation of rhodamine-B in aqueous solution. Under UV radiation, the degradation of rhodamine-B for the specimen without TiO2 and with 0.100 g of TiO2 was 22.8% and 93.5%, respectively. The degradation of rhodamine-B under solar radiation was 9.3% without TiO2, and 99.5% with 8.2 g of TiO2 sprayed on the surface. The self-cleaning effect was observed in all proposed TiO2 sprays, including mortars with a lower concentration of TiO2 on their surface.
The deposition of particles on the surface of the facades of buildings throughout their useful life leads to the loss of performance of their constituent materials in addition to the aesthetic damage caused by stains, leading to the devaluation of the property and costs with maintenance and cleaning. Techniques, mechanisms and materials that seek to mitigate such effects have become a subject widely studied in the area of materials science. Among the techniques, advanced oxidative processes stand out, as they allow the degradation of pollutants through photocatalysis when using established semiconductor materials such as titanium dioxide (TiO2). The application of this semiconductor has a prominent place due to its chemical and physical characteristics. In this work, TiO2 P25 was used as a photocatalyst material to impart self-cleaning properties to the white cement mortar. It was also proven the ability of rhodamine-B to degrade in aqueous solution under artificial ultraviolet radiation and solar radiation. The X-ray diffractometry test indicated that the TiO2 P25 used is composed of 13.77% of rutile phase and 86.23% of anatase. The superficial sprays of TiO2 P25, on the surface of the mortar, proved to be efficient in the degradation of rhodamine-B in aqueous solution. Under UV radiation, the degradation of rhodamine-B for the specimen without TiO2 and with 0.100 g of TiO2 was 22.8% and 93.5%, respectively. The degradation of rhodamine-B under solar radiation was 9.3% without TiO2, and 99.5% with 8.2 g of TiO2 sprayed on the surface. The self-cleaning effect was observed in all proposed TiO2 sprays, including mortars with a lower concentration of TiO2 on their surface.
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Palavras-chave
Argamassa autolimpante, Fotocatálise, Dióxido de titânio, Self-cleaning mortar, Photocataysis, Titanium dioxide