CETMIC   05378
CENTRO DE TECNOLOGIA DE RECURSOS MINERALES Y CERAMICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Modified bentonites as adsorbents for retaining anionic dyes used in tanning industry
Autor/es:
JULIEN BAILLY, CRISTINA VOLZONE; CARLOS CANTERA, ALBERTO GRECO; JULIEN BAILLY
Lugar:
Valencia (Spain) - September 27th-30th 2011
Reunión:
Congreso; XXXI IULTCS Congress; 2011
Institución organizadora:
IULTCS
Resumen:
Clays are natural minerals abundant in nature. Bentonite clays are studied with special attention due to low cost and wide availability throughout of the world. There is extensive literature indicating that the above solids can be used as adsorbents for substances in aqueous medium. Appropriate treatment of the clays can be performed for retaining anionic substances, as are some dyes used in the tanning industry. There is a significant amount of dyes used in tanning industries, which originate effluents that require proper treatment, with the requirements of health authorities, before disposal. An alternative treatment for removing low concentration dyes is using adsorbent substances. The purpose of this study was to evaluate the retention of commercial anionic dyes (Reactive Yellow 15, Direct Black 38, Allura Red, Acid Black 1 and Acid Black 210) by using organo-, acid-modified bentonite clays as adsorbents. The retentions of the dyes by modified bentonite clays were evaluated by using UV-visible complete range spectrum, analyzing the concentrations of dye solutions before and after contact with the adsorbent. The organo-bentonite clay showed an important adsorption capacity for anionic dyes and it could be a suitable adsorbent to retain dyes present in low concentration of waste from tanning industry. However, the natural and acid-bentonite were not effective as adsorbent for anionic dyes. This study also demonstrated that if the evaluation of dye retention by clay is obtained by UV-visible spectra, then, it is recommendable to analyze the equilibrium solution in the complete wavelength range, due to possible modifications of the bands originated by formation of aggregates of dye molecules, the influence of the clay, colour changes, etc. Consequently, incorrect results of the adsorptive capacity of the solid can be obtained.