Isotherm and Kinetic Studies in Dyeing of Citric Acid-Crosslinked Cotton with Cationic Natural Dye

In this study, cotton fabric was crosslinked with citric acid (CA) in the presence of sodium hypophosphite using a pad-dry-cure process under the optimum conditions. The chemistry and morphology of the crosslinked fibers were studied and compared with the untreated fibers using FTIR and SEM. The crosslinked fabric was dyed with the natural cationic dye, berberine, obtained from the roots of Berberis vulgaris. The effects of dyebath conditions, including dye concentration, pH, and temperature, on the color strength of the dyed samples were investigated, and the mean values were compared using SPSS. The isotherm and kinetics of the dyeing of the CA-treated fabric with berberine were investigated. The results showed that the color strength of the dyed samples increased with increasing the dye concentration, pH, and temperature. The best-fitting isotherm and kinetic models were Freundlich and pseudo-second-order models, respectively.