Use of natural clays for adsorption of Methylene Blue and Rhodamine-B in seawater

Use of natural clays for adsorption of Methylene Blue and Rhodamine-B in seawater

• Autor
• Thiago Cardoso da Silva
• Co-autores
• Gabriela Tuono Martins Xavier , Wagner Alves Carvalho , Maria del Rosario Sun-Kou , Yvan Jesús Olortiga Asencios
• Resumo

• This study investigated the adsorption of Methylene Blue (MB) and Rhodamine-B (RhB) in seawater solution using natural clays (Bentonite, sample SC-02) and the corresponding purified clay (mainly montmorillonite). The adsorption tests were carried out in a batch system, with the adsorbent in powder form (mesh sieve <500 ?m). In the adsorption experiments kinetic tests, adsorbent dosage variation, and adsorption isotherms were carried out. The clays were characterized by EDX, XRD, and SEM. The results indicated that clays were very effective in removing synthetic dyes (MB and RhB) in seawater with high removal %. At an adsorbent dosage of 1gclay.L-1 (weight of clay/volume of synthetic dye solution), natural clay (SC-02) and purified clay achieved the equilibrium of adsorption after 90 minutes for both dyes, recording high removal % 90<. The variation of adsorbent dosage also indicated that low adsorbent dosages are highly effective in reaching high synthetic dye removal, thus the maximum removal (Qe= mg of dye removed per gram of clay; mg.g-1) of MB recorded was 217mg.g-1 (obtained by natural clay), whereas the maximum removal of RhB was 160 mg.g-1(obtained by purified clay); both with a dosage of 0.2 gclay.L-1. Furthermore, the adsorption isotherms were adjusted to the Langmuir model and Freundlich models. The results of this research showed that the two clays of this work (natural and purified) were highly effective in removing synthetic dyes in seawater. The salinity of the seawater did not affect/hinder the adsorption of RhB and MB.

• Palavras-chave
• adsorption, Clays, Methilene Blue, Rhodamine-B, Seawater
• Área Temática
• Adsorção aplicada ao meio ambiente