Applicability of ZSM-5 nanozeolite to removal of ternary basic dyes: an adsorption study using high-accuracy UV/Vis-chemometric methods

Abstract

Synthetic dyes in real industrial wastewaters are usually in complex mixtures rather than being pure. In this study, partial least squares and artificial neural network were proposed as two fast and powerful methods to simultaneously determine the concentrations of components in aqueous solutions in the presence of interferences. In addition, a nanometer-sized ZSM-5 zeolite was also synthesized and characterized by scanning electron microscope, X-ray diffraction, and Fourier transform infrared spectroscopy. The results confirmed the formation of ZSM-5 zeolite with an average crystalline size of 49 nm. Various experimental conditions were tested to achieve the highest uptake capacity, which revealed that longer contact times (60 min), higher initial concentrations (115 µM), lower adsorbent dosages (0.2 g dm−3), and basic pH (9) results in the best adsorption capacity of ZSM-5 nanozeolite. Moreover, equilibrium studies indicated that the adsorption of BB41, BR18, and BR46 dyes follows the Langmuir isotherm model and adsorption kinetic data fitted well with the pseudo-second-order model. Finally, a ternary dye solution was prepared and subjected to adsorption at optimum experimental conditions, which resulted in the maximum adsorption capacity of 96.96 µmol g−1.