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Avaliação do Potencial de Lixiviação do Metal Pesado Cd2+ em Argamassas de Cimento Portland

DOI: http://dx.doi.org/10.12702/978-85-89478-40-3-a036

 

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Caroline Venâncio1, Janaíde C. Rocha2 & Malik Cheriaf3

 

Resumo: Este trabalho investiga a possibilidade de retenção do metal pesado cádmio, por meio de argamassas de cimento Portland. Para este propósito as argamassas foram contaminadas com nitrato de cádmio hidratado nas concentrações de 20, 40, 80 e 160 ppm (em relação a massa de cimento utilizada) padrão analítico. Depois de 28 dias de cura, as argamassas foram submetidas ao ensaio de lixiviação de tanque (Tanktest) descrito pela norma holandesa NEN 7375 (2004). Após o ensaio foi verificado o percentual de retenção do metal pesado pelas argamassas e o coeficiente de difusão efetivo para o cádmio nas diferentes concentrações analisadas. Este coeficiente de difusão está relacionado com a taxa de mobilidade do contaminante, ou seja, o potencial de lixiviação deste elemento químico. Os resultados mostraram que o cádmio apresentou alta mobilidade, ou seja, um alto potencial de lixiviação, mas, mesmo após a contaminação das argamassas com cádmio, este metal foi retido acima de 20%, chegando a ser 66% retido. E esta retenção bastante significativa, garante a eficácia das argamassas como uma ótima alternativa de estabilização e solidificação de resíduos sólidos contaminados com cádmio.

Palavras-chave: ensaio de lixiviação, metal pesado, cádmio, argamassas

 

Abstract: This work investigates the possibility of retention of the heavy metal cadmium, by means of Portland cement mortars. For this purpose, mortar were contaminated with hydrate nitrate of cadmium in the respective concentrations of 20, 40, 80 and 160 ppm (in relation to weight of cement used). After 28 days of curing, the mortars were subjected to a leaching test (Tank test) described by the DutchStandard, NEN 7375 (2004). The percentage of retention of heavy metal by the mortars and the effective diffusion coefficient were measured after the leaching test. This diffusion coefficient is related to the mobility rate of contaminants, namely the potential of leaching for each chemical element. Results demonstrated that the cadmium showed a high mobility, but, even after the contamination of the mortars with cadmium, this heavy metal had a retention rate over 20 %, up to 66 % of retention. Such significant retention ensures the efficiency of the mortars in the process of stabilization/solidification of cadmium contaminated wastes.

Key words: leaching test, heavy metals, cadmium, mortars

 

1 Doutoranda Msc. Eng. Civil do PPGEC / UFSC. E-mail: caroline_venancio@yahoo.com.br
2 professor Dr. Ing. Civil do PPGEC / UFSC. E-mail: janaide.rocha@ufsc.br
3 professor Dr. Ing. Civil do PPGEC/ UFSC. E-mail: malik.cheriaf@gmail.com

 

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