Zwitterionic Polymer Brushes Coated with Mesoporous Silica Nanoparticles as Efficient Adsorbents for Dye Removal from Aqueous Solutions

Abstract

In this study, a polymer brush derived from poly(2-(tert-butylamino)ethyl methacrylate)-coated mesoporous silica nanoparticles (PTBAEMA–SO3H@MSNPs) was successfully fabricated. The structure and morphology of PTBAEMA–SO3H@MSNPs were studied using transmission electron microscopy, Fourier-transform infrared spectroscopy, dynamic light scattering, and elemental analysis techniques. The optimal conditions for the removal of rhodamine B (Rh B) and crystal violet (CV) by PTBAEMA–SO3H@MSNPs were determined. The best adsorption efficiency was found at an Rh B concentration of 150 ppm, adsorbent amount of 10 mg, contact time of 40 min, and pH 5 and at a CV concentration of 350 ppm, contact time of 40 min, and pH 9. The adsorption equilibrium was fitted with the Langmuir, Freundlich, Temkin, and Redlich–Peterson isotherm models in both linear and nonlinear forms. Equilibrium data were best fitted with the Langmuir model, with maximum adsorption capacities of 147.78 and 343.57 mg g–1 for Rh B and CV, respectively. The adsorption of both dyes onto the PTBAEMA–SO3H@MSNP adsorbent occurred spontaneously in an exothermic manner and with increased randomness. The adsorption of Rh B and CV onto the PTBAEMA–SO3H@MSNP adsorbent followed pseudo-second-order kinetics. The findings of this study indicate that PTBAEMA–SO3H@MSNPs are highly effective in removing Rh B and CV from water samples.