Eco-friendly superabsorbent composite based on sodium alginate and organo-loess with high swelling properties

Abstract

A novel superabsorbent composite with high swelling properties was synthesized by the grafted co-polymerization of partially neutralized acrylic acid (AA) onto a sodium alginate (NaAlg) backbone in the presence of organo-loess. The FTIR spectra, XRD patterns and SEM micrographs prove that the AA monomers were grafted onto the NaAlg backbone, and the organo-loess dispersed into the polymer matrix that improved the porous structure, which was verified by element mapping. TGA and DSC results indicate that the incorporation of loess enhances the thermal stability of the superabsorbent. Swelling results confirm that proper amount of organo-loess in the superabsorbent can enhance the swelling capability and salt-resistant performance. The maximum equilibrium water absorbency of the superabsorbent composite incorporated with 10 wt% organo-loess in distilled water and 0.9 wt% NaCl aqueous solution were 656 g g⁻¹ and 69 g g⁻¹, respectively. Furthermore, the superabsorbent composite exhibited good buffer ability to external pH in the range from 4 to 10 and water retention ability. According to the performance of the eco-friendly superabsorbent composite, it can be used as a promising candidate for applications in various fields.