Hybrid hydrogels of hyperbranched poly(ether amine)s (hPEAs) for selective adsorption of guest molecules and separation of dyes

Abstract

We herein report a novel hybrid hydrogel (SiO_1.5-hPEAs-Gels), which was fabricated by the direct hydrolysis of trimethoxysilyl groups containing hyperbranched poly(ether amine)s (TMS-hPEAs) in water. The adsorption behaviors of guest molecule dyes by the obtained SiO_1.5-hPEAs-Gels were investigated systematically. The adsorption process was found to follow pseudo-first-order kinetics at the initial stage, but followed pseudo-second-order kinetics at later stages. SiO_1.5-hPEAs-Gels exhibited a quick adsorption of guest dyes such as Ponceau S (PS), Rose Bengal (RB), Neutral Red (NR) and Methyl Orange (MO) with a high adsorption capacity (Q_eq), and very slow adsorption of Methylene Blue trihydrate (MB) and Rhodamine 6G (R6G) with a low adsorption capacity. The big difference in the adsorption behaviors of dyes indicated that the SiO_1.5-hPEAs-Gels can adsorb guest molecules selectively. Based on these results, we demonstrated a method for dynamic separation of a mixture of dyes, which can be controlled by the contact time. For example, SiO_1.5-hPEA211-Gel can adsorb and remove only PS selectively from a mixture of PS/MB. These characteristics will give SiO_1.5-hPEAs-Gels potential for controlled separation.