Performance of MnO2 nanoparticles-coated cationic CTAB for detoxification and decolorization of sulfonated remazol red and reactive black 5 dyes from water

Abstract

In this research, fabrication and functionalization of MnO2 nanoparticles with cetyltrimethylammonium bromide (MnO2 NPs-CTAB) were confirmed for removal of two reactive anionic sulfonated azo dyes: remazol red (RR) and reactive black 5 (RB5). The modified nanosorbent was characterized via X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, BET analysis, SEM and HRTEM studies. Various adjustable parameters, for instance nanosorbent mass, pH, reaction contact time, dyes concentration, reaction medium temperature and interfering compounds, were also explored. The adsorption processes for both dyes were favorable fitted with the Langmuir adsorption isotherm model. The highest adsorption capacities were 40.00 and 38.46 mg g−1 for RR and RB5, respectively. Various kinetic models were employed, and the results manifested the preferable fitting for the pseudo-second-order one. The standard thermodynamic parameters (ΔH°, ΔS° and ΔG°) have been calculated, and the outcomes illustrated that RR and RB5 dyes adsorption was exothermic and spontaneous. Finally, the potential applications of MnO2 NPs-CTAB under optimum conditions for adsorptive decolorization and detoxification of RB5 and RR from various water samples, for instance tap water, raw water and seawater, were investigated.