Novel nanoparticles modified composite eco-adsorbents—A deep insight into kinetics modelling using numerical surface diffusion and artificial neural network models

Abstract

The first main objective of this work was to develop and investigate novel green composite adsorbents for the efficient removal of malachite green from their aqueous solutions. In this study, two simple methods of the chemical modification of extracting agricultural wastes were proposed. Rapeseed meal (RM) was modified with magnetic nanoparticles (MNs) by a co-precipitation reaction and with polypyrrole (PPy) by an in situ chemical oxidative polymerization. Maximum adsorption capacities of 836.2 and 93.3mgg−1 were observed for RM–MNs and RM–PPy respectively. Both composite adsorbents were characterized by scanning electron microscopy (SEM–EDS), X-ray diffraction (XRD) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The second main goal of the investigation was to study the rate of dye adsorption from aqueous effluents onto the composite adsorbents. The batch adsorption kinetics were described using the surface diffusion model (SDM), pseudo-first-order (PFO) and pseudo-second-order (PSO) models, and also by empirical artificial neural network (ANN) simulation, which is a new approach for the modelling of the kinetics of adsorption with high accuracy. The SDM fitted the experimental data with very good accuracy, revealing that the overall rate of adsorption was mostly controlled by surface diffusion. Since scientific literature contains only a few studies on the modelling of the kinetics of adsorption onto composite adsorbents using numerical methods, a detailed investigation should be performed.