In this study, the mucilage of O. basilicum was used for decolorization
of congo red (CR). Congo red is a benzidine-based anionic
diazo dye and the first synthetic dye capable of dying cotton
directly. The disodium salt of CR (Fig. 1) is responsible for dying
the fabric full red (Meroufel et al., 2013). CR is considered as a
xenobiotic compound that resists biodegradation. In the present
study, CR was selected as a model dye due to its wide application
range and recalcitrant nature (Sarwan et al., 2012). Patel and Vashi
(2012) have previously investigated the effectiveness of three naturally
prepared coagulants including surjana seed powder, maize
seed powder and chitosan for CR removal from its aqueous solution.
Maximum percentage of CR removal was found to be 98.0% by
using 25 mg/L surjana seed powder.