Evaluation of adsorptive and synergistic effects for elimination of crystal violet from aqueous solution

This study investigated removal of crystal violet ( CV) from aqueous solutions by iron oxide-coated zeolite (ICZ), potassium permanganate-coated zeolite (MCZ), and zero-valent iron (ZVI) and evaluated synergistic effect of sequential system. The adsorbents were characterized using energy-dispersive X-ray analysis and scanning electron microscopy images. The effects of various parameters were examined. The results showed that basic pH generally favored adsorption for ICZ and MCZ but significant CV removal was possible even under neutral conditions. ICZ and MCZ exhibited the best performance at pH 11. ZVI displayed the best performance at pH 7, and the adsorption was very fast. The experimentally obtained data for the adsorption of CV onto ICZ, MCZ, and ZVI were modeled using the isotherm models of Freundlich and Langmuir. The kinetics of CV onto ICZ, MCZ, and ZVI was best described by the pseudo-second-order kinetic model. This study reveals that it is possible to use ICZ, MCZ, and ZVI as nanoparticles, an alternative for the adsorbents that are already being used, in the removal of CV from industrial wastewater. Furthermore, the combination of ZVI and MCZ enhances the decolorization of the solutions. The best result was found with the ZVI-MCZ sequential system.