Efficient Sono-sorption Removal of Malachite Green by Nano-TiO 2 /CuO: A Multivariate Study

Abstract

In this research study, the TiO 2 /CuO nanocomposites adsorbent were successfully synthesized by employing a bottom-up approach for efficient removal of Malachite Green (MG) dye in an ultrasonic-assisted adsorption process. Morphological, structural, and chemical studies were performed using SEM, EDX, and FTIR spectroscopy. Central composite design with five (05) factors was employed to design the adsorption experiment while response surface methodology was used to evaluate optimum operating parameters (OOP). The OOP for the 99.4% removal of MG was observed at a pH of 6.9, adsorbent usage of 23.0mg and time duration of 7.6min, respectively. In the kinetics study, the model dye followed pseudo-second order and Freundlich isotherm model was found as the best fitted model. In addition, desorption study was performed in different solvents to regenerate the spent adsorbent which was successfully employed for six (06) cycles. Finally, thermodynamic studies were performed to assess the feasibility of the adsorption process, the negative ΔG o and positive ΔS o values illustrate the spontaneous nature of the dye adsorption process.