Synthesis of tragacanth composite hydrogels, polyvinyl alcohol and tannins by electron beam irradiation and its application for methyl violet removal from aqueous media

In the current study, a biocompatible hydrogel sorbent is prepared by chemical conjunction between gum tragacanth polymer chains and polyvinyl alcohol using electron beam irradiation followed by chemical stabilization of tannin on its surface. The synthesized composite hydrogels are analyzed using infrared spectroscopy, scanning electron microscope, X-ray diffraction method and thermogravimetric analysis. Then, the ability of the prepared hydrogel sorbent to remove methyl violet from the aqueous solution is investigated. The sorption data are analyzed via Langmuir, Freundlich and Temkin isotherm models and turned out to be most consistent with the Langmuir isotherm. The maximum Langmuir sorption capacity of gum tragacanth-polyvinyl alcohol/tannin composite hydrogel for the removal of methyl violet was 35.21 mg g(-1). The sorption process is found to be endothermic and spontaneous. Experimental data are also analyzed using kinetic equations of pseudo-first-order, pseudo-second-order and Elovich, and are found to be in good agreement with the pseudo-second-order model.

Automated summary

A biocompatible hydrogel sorbent was prepared by chemically conjugating gum tragacanth polymer chains with polyvinyl alcohol, and then chemically stabilizing tannin on its surface using electron beam irradiation. The synthesized composite hydrogels were characterized using various analytical techniques. The ability of the hydrogel sorbent to remove methyl violet from aqueous solution was investigated, and the sorption data were analyzed using different isotherm and kinetic models.