One-step synthesis of super-absorbent nanocomposite hydrogel based on bentonite

Abstract

The nanoparticles of bentonite can be easily synthesized by hydrothermal treatment with microwave-assisted method. The products were characterized by XRD, FTIR, BET, SEM, EDS, and DLS. Results have revealed that the nano-bentonite was in nanometer scale with particles size of 200–300 nm. The SEM analysis of the nano-bentonite dispersion showed that a decrease in agglomeration and surface roughness. The nano-bentonite possessed high surface area (152.4 m ^2 .g ^−1 ) and pore volume (0.25 cm ^3 .g ^−1 ). Additionally, nanocomposite hydrogels (NB/PAA) were synthesized through the free-radical polymerization of acrylic acid (PAA) in the presence of the as-synthesized nano-bentonite (NB). The presence of NB in hydrogel matrix may improve the tensile strength of hydrogel. The tensile strength of the hydrogel increases from 0.294 to 1.609 MPa when NB content was 1.0% (NB10/PAA). Under the optimum conditions, the nanocomposite hydrogels (NB10/PAA) exhibited high water absorption capacity of 420.0 ${g}_{water}.{g}_{hydrogel}^{-1}.$ These findings contribute to the sustainable development and green chemistry.

Keywords

• nano bentonite
• nanocomposite hydrogels
• superabsorbent
• water absorption