Removal of textile dyes from water by jute stick activated carbon: process optimization and isotherm studies

Abstract

In this study, jute stick derived activated carbon (JSAC) has been evaluated as an adsorbent to remove textile dyes namely acid red-1 (AR-1), reactive orange-16 (RO-16), and methylene blue (MB) from water using the Box–Behnken model of response surface methodology (RSM). The direct and interaction effects of four independent process parameters namely solution pH, initial dye concentration, adsorbent dose, and time were investigated and optimized for textile dye by using ANOVA. The optimum conditions for maximum % dye removal were found to be pH-3, initial dye concentration-500 mg L−1, adsorbent dose-0.9 gL−1, and time-110 min for AR-1; pH-3, initial dye concentration-350 mg L−1, adsorbent dose-1.5 g L−1, and time-110 min for RO-16, and pH-11, initial dye concentration-415 mg L−1, adsorbent dose-0.7 g L−1, and time-86 min for MB, respectively. Adsorption equilibrium investigations were carried out with Langmuir, Freundlich, and Jovanovic models. Based on error analysis, Langmuir isotherm was found the best-fitted model with maximum adsorption capacities of 588.2, 156.3, and 384.6 mg g−1 for AR-1, RO-16, and MB, respectively. The dimensionless factor, RL values (range: 0.0152–0.2665) also indicated spontaneous and favorable adsorption of studied dyes onto JSAC. Dye loaded adsorbents were easily regenerated with 0.1 M HCl (for MB) and 0.1 M NaOH (for AR-1/RO-16) and reused up to the 4th cycle. The present investigation indicated that JSAC, with a highly porous and stable structure coupled with various functional groups, holds immense potential as a new adsorbent for textile dyes.