Interaction of Indigo carmine with naturally occurring clay minerals: An approach for the synthesis of nanopigments

Abstract

Dyes are organic colorants used in textile, paint, printing and many more industries for different purposes, especially to make the products more attractive. However, these organic compounds can not be removed easily from water bodies due to their non-biodegradable nature. In this context, this paper aims at the application of clay minerals and their organo forms which were used to remove the anionic dye, Indigo Carmine from aqueous media at different conditions such as pH, contact time and initial concentration by employing batch extraction method. Synthesis of organo clay was done through ion-exchange method using cationic surfactant (Cetylpyridinium chloride). The adsorbents (before and after adsorption of dye) were characterized using different analytical techniques like X – Ray diffraction, Fourier Transform Infra-Red spectroscopy, UV–vis spectroscopy. During the study, it was found that the efficiency for uptake of anionic dye was more for organo clay (Organo Montmorillonite − 330 mg g−1 and Organo Bentonite − 468 mg g−1) at favorable acidic condition as the surface of Montmorillonite and Bentonite become positively charged after interaction with surfactant results in electrostatic interaction between dye and organo clays. As there was no significant change in diffraction peak of adsorbent after interaction with dye suggested the surface interaction of dye which was further supported by FT-IR studies.