Nanoparticles Loaded Biopolymer as Effective Adsorbent for Adsorptive Removal of Malachite Green from Aqueous Solution

Abstract

In the present study, the biocompatible nanocomposite (nickel oxide nanoparticles loaded chitin beads (NiO NPs/CH)) was synthesized, characterized by using scanning electron microscopy (SEM) and Fourier transform infrared (FT–IR) analysis and then study its prospective application towards adsorption of malachite green (MG) dye. Further, batch studies were conducted to evaluate the adsorption capacity of nanocomposite, and the effects of various parameters, i.e., pH, adsorbate concentration, contact time, dosage of adsorbent and temperature, were investigated. The results revealed that the amount of MG adsorbed on the adsorbent increases with increasing initial dye concentration and by decreasing temperature. The equilibrium MG adsorption data on NiO NPs/CH were best described by the Langmuir isotherm model. Besides, the adsorption kinetics followed pseudo-second-order rate equation. Thermodynamic parameters such as free energy of adsorption (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) changes were calculated, and the results suggested that the adsorption process was spontaneous and exothermic in nature. Based on the results, it was concluded that the nanocomposite can be sustainably prepared and efficiently used for the adsorptive removal of MG from colored aqueous solutions.