No presente trabalho foi realizada a síntese dos pós de TiO2 dopados com ferro e co-dopados com chumbo e vice-versa. O método de síntese utilizado foi o sonoquímico, que se mostrou eficiente para a síntese desse tipo de material.
As análises de DRX mostraram que os pós de titânia se encontram na fase anatase e que a dopagem e co-dopagem ocorreram com sucesso, não mostrando fases secundárias.
A microscopia eletrônica de transmissão mostrou uma morfologia aglomerada e esférica para a amostra de TiO2 pura, dopada com 0,5 %, 1% de chumbo e dopada com 0,25% de ferro e co-dopada com 0,25% de chumbo mostrou uma morfologia irregular e aglomerada. As demais amostras apresentaram morfologia irregular, porém desaglomerada. O tamanho médio das partículas pode ser calculado e as partículas se mostraram muito pequenas, como visto nas fotomicrografias. O resultado de EDS confirmou a presença dos dopantes e co- dopantes na estrutura e o cálculo da distância interplanar confirmou que o TiO2 se encontra na fase anatase.
A energia de banda das amostras diminuiu com a adição dos dopantes e co- dopantes, principalmente aquelas amostras que continham uma maior quantidade de ferro na sua estrutura. A redução do Egap mostrou que os pós podem possuir um bom comportamento sob a luz visível para a degradação do azul de metileno.
A análise de área superficial através do método BET mostrou que a adição de íons dopantes na estrutura do dióxido de titânio reduziu a área superficial em relação a amostra pura, corroborando com os resultados de gap.
A adição dos dopantes e co-dopantes no TiO2 reduziram a atividade fotocatalítica do material sob irradiação UV, visto que a quantidade de dopante e co- dopante ultrapassaram os valores considerados como “ótimos”. Já para as amostras que estavam dentro do valor “ótimo”, a atividade fotocatalítica teve um bom desempenho em relação as que ultrapassavam esse valor ótimo. Para as amostras degradadas sob radiação solar, todas tiveram um aumento na atividade fotocatalítica quando comparada com as amostras irradiadas sob luz UV, principalmente as amostras que cumpriram a regra do valor ótimo, mostrando melhores resultados quando comparado a titânia pura e comercial, corroborando com o resultado de gap que com a dopagem trouxe o titânio para a faixa do visível. A análise do mecanismo
de catálise mostrou que os buracos estão fortemente ligados a atividade fotocatalítica do TiO2 co-dopado, enquanto que os radicais OH• não participam fortemente dessa reação.
Na análise antimicrobiana, as amostras TiO2:1%Fe:3%Pb, TiO2:1%Pb1%Fe e TiO2:1%Pb:3%Fe apresentaram sinergismo frente as duas bactérias, diferente do restante das amostras que foram co-dopadas. Além disso, as amostras TiO2:1%Fe:3%Pb e TiO2:1%Pb:1%Fe apresentaram um diâmetro maior que o diâmetro mínimo exigido para a eficiência da ação antimicrobiana, se comportando como bons agentes antimicrobianos.
Apesar da propriedade de fotocatálise ser reduzida com o aumento dos íons dopantes e co-dopantes, o aumento da concentração no dióxido de titânio fez com que a propriedade antimicrobiana fosse melhorada, concluindo que o material se trata de um pó multifuncional que pode ser utilizado tanto como agente antimicrobiano e como catalisador para degradação de poluentes orgânicos dos efluentes.
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