Use este identificador para citar ou linkar para este item: https://locus.ufv.br//handle/123456789/19893
Tipo: Artigo
Título: Adsorption of the herbicides diquat and difenzoquat on polyurethane foam: kinetic, equilibrium and computational studies
Autor(es): Vinhal, Jonas O.
Nege, Kassem K.
Lage, Mateus R.
Carneiro, José Walkimar de M.
Lima, Claudio F.
Cassella, Ricardo J.
Abstract: This work reports a study about the adsorption of the herbicides diquat and difenzoquat from aqueous medium employing polyurethane foam (PUF) as the adsorbent and sodium dodecylsulfate (SDS) as the counter ion. The adsorption efficiency was shown to be dependent on the concentration of SDS in solution, since the formation of an ion-associate between cationic herbicides (diquat and difenzoquat) and anionic dodecylsulfate is a fundamental step of the process. A computational study was carried out to identify the possible structure of the ion-associates that are formed in solution. They are probably formed by three units of dodecylsulfate bound to one unit of diquat, and two units of dodecylsulfate bound to one unit of difenzoquat. The results obtained also showed that 95% of both herbicides present in 45 mL of a solution containing 5.5 mg L^−1 could be retained by 300 mg of PUF. The experimental data were well adjusted to the Freundlich isotherm (r^2 ≥ 0.95) and to the pseudo-second-order kinetic equation. Also, the application of Morris-Weber and Reichenberg equations indicated that an intraparticle diffusion process is active in the control of adsorption kinetics.
Palavras-chave: Adsorption
Kinetic modeling
Diquat
Difenzoquat
Polyurethane foam
Editor: Ecotoxicology and Environmental Safety
Tipo de Acesso: Elsevier Inc.
URI: http://dx.doi.org/10.1016/j.ecoenv.2017.08.005
http://www.locus.ufv.br/handle/123456789/19893
Data do documento: 9-Ago-2017
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