Adsorption of Anionic Dye on the Acid-Functionalized Bentonite

Materials

RomualdoRodrigues Menezes¹  AlissonMendes Rodrigues¹  Gelmiresde Araújo Neves¹  JucielleVeras Fernandes¹ 

[1] Programa de Pós-Graduação em Ciência e Engenharia de Materiais (PPG-CEMat), Universidade Federal de Campina Grande, Av. Aprígio Veloso-882, Bodocongó, Campina Grande-PB 58429-900, Brazil;

关键词: bentonite;    methylene blue;    methyl orange;    acid functionalization;    adsorptive capacity;   

DOI  :  10.3390/ma13163600

来源: DOAJ

【 摘 要 】

The efficiency of acid treatment on natural calcium bentonite (natural bentonite) for anionic dye adsorption was investigated using methyl orange (MO) as a probe. Additionally, adsorption experiments were accomplished between the natural bentonite, acidified bentonite, and a cationic dye (methylene blue, MB). Acid functionalization in natural bentonite (RF) was carried out with HCl and H₂SO₄ acids (RF1 and RF2, respectively). The samples were characterized by chemical analysis, mineralogy, particle size, and thermal behavior with the associated mass losses. The adsorption efficiency of MO and MB dyes was investigated by the effects of the initial concentration of adsorbate ($C_i$) and the contact time ($t_c$). The acid treatment was efficient for increasing the adsorption capacity of the anionic dye, and the $Q_{max}^{exp}$ values measured were 2.2 mg/g, 67.4 mg/g e 47.8 mg/g to RF, RF1 e RF2, respectively. On the other hand, the acid functionalization of bentonite did not significantly modify the MB dye adsorption. The Sips equation was the best fit for the adsorption isotherms. Thus, we found that the acid-functionalized bentonite increases the anionic dye adsorption by up to 8000%. The increased adsorptive capacity of acidified bentonite was explained in terms of electrostatic attraction between the clay surface and the dye molecule.

【 授权许可】

Unknown