Remoção de Pb(II) e Cr(VI) de efluentes industriais utilizando resíduos de Ipê (Tabebuia spp.), Maçaranduba (Manilkara spp.) e Pequiá (Caryocar spp.)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

(Brazilian) Sawdust samples of Caryocar spp.; Manilkara spp. and Tabebuia spp. have been used for Cr(VI) and Pb(II) adsorption from water at 25oC. The series of adsorption isotherms were adjusted to a modified Langmuir equation from data obtained by suspending the sawdust with K2Cr2O7 or Pb(NO3)2 solutions, which gave the maximum number of moles adsorbed as 35.39 2.61; 63.67 8.35 and 168.57 13.57 mg g-1 for Caryocar spp.; Manilkara spp. and Tabebuia spp., respectively for Cr(VI) and 89.10 8.28; 145.04 12.43 and 95.31 8.28 mg g-1 for Caryocar spp.; Manilkara spp. and Tabebuia spp., respectively for Pb(II). Thermodynamic data of interactions were studied by the calorimetric titration of Cr(VI) and Pb(II) in aqueous solution. Gibbs free energies were negative for all systems and the adsorption interactions presented the following exothermic enthalpic values: -3.62 0.22, -4.17 0.23 and -3.85 0.25 kJ mol-1 for Caryocar spp.; Manilkara spp. and Tabebuia spp., respectively for Cr(VI) and -1.99 0.11; -3.20 0.21 and -2.27 0.11 kJ mol-1 for Caryocar spp.; Manilkara spp. and Tabebuia spp., respectively, for Pb(II). All liquid/solid interface adsorptions were entalpically and entropically driven. These sawdust samples were also used to remove chromium from tannery wastewater. The application of Caryocar spp.; Manilkara spp. and Tabebuia spp. reduced the amount of chromium from 2.11 0.18 mg L-1 to 1.15 0.10; 0.29 0.02 and 0.26 0.02 mg L-1, respectively. These sawdust samples were also applied to remove Pb(II) from wastewater of a battery industry, which presented Pb(II) concentration of 2.66 mg L-1. Pb(II) concentration in this wastewater was reduced to 2.49; 0.45 and 0.47 mg L-1 by application of Caryocar spp.; Manilkara spp. and Tabebuia spp., respectively.

ASSUNTO(S)

chumbo e cromo serragem efluentes indústrias quimica inorganica metais pesados

ACESSO AO ARTIGO

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