Treatment of C.I. Reactive Blue-21 effluent by microcrystalline cellulose grafted with APTES: kinetics, isotherm and thermodynamic study

Abstract

Abstract The adsorption removal of C.I Reactive Blue 21 (RB-21) dye from aqueous solution by commercial MCC was successfully modified with aminopropyltriethoxysilane. The various physiochemical attributes like initial dye concentration, contact time, solution pH, adsorbent dose and temperature were evaluated. The surface modification was characterised and confirmed with specific surface area analyser using Brunauer–Emmett–Teller, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Energy Dispersive Spectrometer and X-ray diffraction. The adsorption kinetics, isotherms, and thermodynamics were explored. The Langmuir, Frendlich and Redlich-Perterson isotherm models were studied with the Langmuir adsorption isotherm model showing the best fit with the adsorption capacity of 30 mg g− 1 at 323 K. The kinetic data was considered using pseudo-first-order and pseudo-second-order. The results indicated that the pseudo-second-order model was preferred with good correlation. The thermodynamic attributes like changes in standard enthalpy, standard entropy and standard Gibbs free energy were assessed at different operating temperatures. Hence, current research work shows efficient removal of RB-21 dye from effluent solution by modified microcrystalline cellulose.

Keywords

• RB-21
• Modified microcrystalline cellulose
• Adsorption
• Thermodynamic
• Isotherm
• Kinetics