pH-responsive gum tragacanth hydrogels for high methylene blue adsorption.

ILLANES, CRISTIAN O.; A. TAKARA; OCHOA, NELIO A.

JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2023

0268-2575

Background: Biobased hydrogels are used in many applications due to their easy availability, low cost, and versatility to acquiredifferent structures. However, there is scarce information about the changes generated in the matrix´s microstructure aftercrosslinking reactions. The effect of the crosslinking reaction using glutaraldehyde on the micro- and macrostructure of tragacanthgum hydrogels (TG GLU) was evaluated.Results: New acetal groups, which increase with increasing glutaraldehyde (GLU), produced less packed biopolymeric structureswith more thermal stability. Due to demethoxylation, a higher amount of free carboxylic groups after crosslinking reactionwere determined in TG GLU. Crosslinked hydrogels presented a higher water uptake capacity with a pH-responsivebehavior with suitable thermal and mechanical properties. Besides this, the highest adsorptive capacity of methylene blueachieved was qm = 530 mg/g.Conclusions: pH responsive gels from tragacanth were obtained after crosslinking with glutaraldehyde. Chemical and microstructuralchanges affected the methylene blue adsorption, resulting in hydrogels with improved adsorptive properties. Theseproperties give the TG-GLU hydrogels some features that