DLS – Nanopartículas de óxido de cobalto

O Quadro 3 expõem em qual diâmetro em escala nanométrica a porcentagem média das partículas de óxido de cobalto. O processo de agregação e decantação se mostra ainda mais presente nestas análises de óxido de cobalto utilizando água como dispersante, apresentando uma porcentagem média de 50,4%

das partículas no intervalo de 78,82 – 122,4 .nm. Mas ainda é possível relatar a presença de nanopartículas uma vez que uma boa porcentagem se encontra entre 1 e 100 nm de diâmetro, como pode ser observado na Figura 19.

Quadro 3: Porcentagem média do tamanho das partículas de óxido de cobalto.

Tamanho nm Porcentagem de contribuição (%) Tamanho nm Porcentagem de contribuição (%) 28,21 0,0 220,2 5,0 32,67 0,0 255 4,7 38,84 0,0 295,3 4,4 43,82 0,0 342 4,1 50,75 0,0 396,1 3,7 58,77 0,0 458,7 2,9 68,06 0,0 531,2 2,1 78,82 4,2 615,1 1,3 91,28 13,6 712,4 0,7 105,7 18,2 825 0,3 122,4 14,4 955,4 0,1 141,8 9,0 1106 0,0 164,2 6,0 1281 0,0 190,1 5,2 1484 0,0 .

Figura 19: Histograma do número de médio de partículas pelo diâmetro médio em nanômetros

realizados para amostra de óxido de cobalto disperso em água - DLS Zetasizer. 6 CONCLUSÃO

Para as análises de infravermelho pode-se concluir que ambos os materiais foram recobertos com sílica, sendo passíveis para funcionalização e

aplicação das mesmas como adsorventes. As amostras de magnetita coincidem os valores das bandas com as encontradas na literatura, Já para as amostras de óxido de cobalto os resultados demonstram que nenhuma das amostras foi possível detectar bandas referentes aos estiramentos de Co-O, ainda não se sabe o motivo para que os espectros apresentem-se de tal forma.

Pode-se confirmar que as partículas geradas na síntese dos óxidos de ferro e cobalto se encontram em escala nanométrica, porém ainda necessita de um maior estudo sobre os meios de dispersão dos mesmos para que as amostras permaneçam em suspenção.

Esta nova metodologia mecanoquímica obteve sucesso para a síntese de nanopartículas magnéticas de óxidos de ferro e cobalto, uma vez que o resultante deste procedimento apresentam partículas sensíveis à presença um campo magnético externo.

7 PERSPECTIVAS FUTURAS

Mais estudos devem ser feitos para caracterizar os materiais originados desta nova tecnologia, pois as análises aqui presentes não confirmam a formação da estrutura cristalina de Co3O4 e Fe3O4. Afinal, não é possível concluir ainda qual a

constituição precisa do material produzido.

Em seguida será realizada a funcionalização de sua superfície para aplicação na remoção de íons de metais tóxicos em efluentes. Para que assim algumas isotermas possam ser elaboradas e desta maneira a capacidade de adsorção dos materiais seja avaliada.

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