Removal of crystal violet by Cu-chitosan nano-biocomposite particles using Box–Behnken design

Abstract

Copper nanoparticles (CuNPs) impregnated biocomposites (Cu/chit-NBC) were prepared and characterized by the state-of-the-art analytical techniques. The CuNPs were in the average size ranges of 45.6–63.7 nm and 86.4 nm as confirmed by scanning electron microscopy and dynamic light scattering, respectively. To decolorize the crystal violet from the aqueous medium, fabricated Cu/chit-NBC was applied as an adsorbent. Box–Behnken design using three independent variables was adopted to optimize the Crystal Violet (CV) decolorization process. Under the optimum conditions of temperature 42.7 °C, pH 9.5, and 149.9 mg L−1 dose of adsorbent, 99.7 ± 0.2% decolorization was observed. Cu/chit-NBC also showed a very high dye removal capacity in simulated industrial textile effluents of around 99.7 ± 0.2%. The CV decolorization was consistent with pseudo-second-order kinetics and best fitted with the Freundlich adsorption isotherm. The nature and the potential processes involved in interactions between the CV and the nano-bioadsorbents during discoloration have been discussed in this paper.