Foundry sands as low-cost adsorbent material for Cr (VI) removal.
Environ Technol
; 34(9-12): 1267-81, 2013.
Article
em En
| MEDLINE
| ID: mdl-24191460
ABSTRACT
The potential of foundry sands, industrial waste from the iron foundry industry, was evaluated for the removal of Cr (VI) using discontinuous assays. Chemical foundry sands are composed of fine silica sand, furanic resins as binder, chemical catalyst and residual iron particles. The influence ofpH, agitation rate and metal concentration on the removal process was investigated. Kinetic and equilibrium tests were conducted to determine Cr (VI) removal from aqueous solutions at a temperature range of 25-55 degrees C. Cr (VI) removal of 40-100% for a range of pH 6-1.6 was obtained. This removal was attributed to the presence of a large number of protonated silanol and aluminol groups. Cr (VI) adsorption in foundry sands follows a pseudo-second-order kinetic reaction (Ho model, r2 > 0.999) reaching kinetic constants of 0.341, 0.551, 0.775 and 0.920 g/mg h at 25, 35, 45 and 55 degrees C, respectively. The adsorption data were fitted to the Langmuir adsorption isotherm model (r > 0.99) obtaining adsorption capacities (q(max)) of 1.99, 2.40, 2.50, and 3.14 mg Cr (VI)/g sand at 25, 35, 45 and 55 degrees C, respectively. Calculated Gibbs free energy change (deltaG0), adsorption energy (E) and activation energy (E(a)) values indicate that a physisorption mechanism governs Cr (VI) adsorption process in foundry sands.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Poluentes Químicos da Água
/
Cromo
/
Dióxido de Silício
/
Purificação da Água
/
Resíduos Industriais
Tipo de estudo:
Health_economic_evaluation
Idioma:
En
Revista:
Environ Technol
Assunto da revista:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Espanha