A novel tetrafluoroterephthalonitrile-crosslinked quercetin/chitosan adsorbent and its adsorption properties for dyes

A new tetrafluoroterephthalonitrile crosslinked quercetin/chitosan (T-QT/CS) adsorbent was successfully synthesized for the adsorption of both cationic and anionic dyes in water. The structure of the resulting T-QT/CS was characterized by FTIR, 13 CNMR, TGA, BET, SEM, and XPS, and the surface-charge property of the T-QT/CS at different pH values was determined by the zeta potential measurement. It was found that the adsorption behavior of the T-QT/CS for the cationic methylene blue (MB) dye and the anionic orange G (OG) dye conformed to the pseudo-second-order kinetic model and the linear Langmuir isotherm model. Furthermore, basing on the linear Langmuir isotherm model, the T-QT/CS possessed good dye-adsorption ability, and the maximum adsorption capacities of the T-QT/CS for the MB (at pH=9) and OG (at pH=2) at 303 K were 917.4 mg/g and 349.9 mg/g, respectively. The thermodynamic experimental results showed that the MB and OG adsorption processes of the T-QT/CS were endothermic and spontaneous. In addition, the T-QT/CS exhibited good reused ability for the adsorptions of MB and OG even after five adsorption-desorption experiments.