Kapok fibers modified with cationic surfactants: Structural insights and efficient removal of Cr(VI) and bisphenol A

Autor(es)

Nunes, Mario A. B. S. ; Boas, Anna C. D. Vilas ; Fernandes, Rodrigo ; Itri, Rosangela ; Marques, Leandro R. ; Ando, Romulo A. ; Petri, Denise F. S.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Colloid and Interface Science; v. 683, p. 16-pg., 2024-12-25.

Resumo

In this study, kapok fiber (KF) a hollow and hydrophobic fiber, was modified with cetyltrimethylammonium bromide (CTAB) or cetylpyridinium chloride (CPC), rendering adsorbed amount of similar to 0.75 x 10(-3) mol/g. Small- angle X-ray scattering (SAXS) measurements of dry KF/CTAB and KF/CPC evidenced a periodic distance of similar to 2.6 nm and 2.8 nm, respectively, suggesting the presence of hemimicelles on the surface. KF/CTAB and KF/CPC were used as adsorbents in batch and column adsorption experiments to remove Cr(VI) ions, Bisphenol A (BPA), and their binary mixtures from synthetic solution and fresh water. The adsorbed amounts of Cr(VI) ions on KF/CTAB and KF/CPC, as determined from batch experiments, were 48.62 mg/g and 34.17 mg/g, respectively. X-ray photoelectron spectroscopy (XPS) analysis showed that Cr(VI) adsorption on KF/CTAB involved bromide displacement, while chloride remained on KF/CPC. Moreover, Cr(VI) ions were reduced to Cr(III) ions due to a possible oxidation of gamma-sitosterol, one component of the KF wax. Density Functional Theory (DFT) calculations indicated that the interaction energy of CTAB-Cr(VI) pair (-167.8 kcal/mol) is more favorable than that of the CPC-Cr(VI) pair (-147.8 kcal/mol). The adsorbed amounts of BPA on KF/CTAB and KF/CPC were 41.66 mg/g and 22.62 mg/g, respectively. XPS analysis indicated the appearance of an O-H peak at 533 eV after the adsorption of BPA, aligning with DFT calculations that predicted interactions between the counter-ions (Br- or Cl-) and BPA hydroxy groups. In column adsorption experiments, Cr(VI) ions were more effectively adsorbed onto KF/CTAB in the presence of BPA, demonstrating the potential of KF/CTAB for the simultaneous remediation of mixed contaminants in water treatment. (AU)

• Processo FAPESP: 21/07305-8 - Remoção de resíduos orgânicos e metálicos por meio da adsorção assistida por campo magnético externo utilizando bioadsorventes de bagaço de cana e polidopamina contendo óxido de grafeno magnético
• Beneficiário: Mário André Brito Seixas Nunes
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 18/13492-2 - Arcabouços sintéticos e naturais aplicados à medicina regenerativa
• Beneficiário: Luiz Henrique Catalani
• Modalidade de apoio: Auxílio à Pesquisa - Temático