Radiation synthesis of polyvinyl alcohol/acrylic acid/magnesium oxide composite hydrogel for removal of boron from its aqueous solution

Abstract

Various compositions of polyvinyl alcohol/acrylic acid Poly(PVA/AAc) hydrogels are prepared using of gamma radiation. The properties of the prepared poly(PVA/AAc) hydrogel and poly(PVA/AAc/magnesium oxide (MgO)) composite hydrogel were characterized by various techniques such as fourier transform infrared (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy. The TEM and XRD patterns of MgO nanoparticles indicate that the MgO with average particle size ranged from 18.11 nm to 45.6 nm. The gel (%) of the prepared poly(PVA/AAc) hydrogel with different contents of AAc increased with increasing both irradiation dose and AAc content. The swelling (%) of poly(PVA/AAc) hydrogel at different irradiation doses and different AAc contents found to be decreased with increasing both irradiation dose and AAc contents. The effect of incorporation of MgO nanoparticles into the poly(PVA/AAc) hydrogel matrix for absorption of boron from aqueous solution under various factors such as different concentrations of boron, different concentrations of MgO, and at different treatment times was investigated. From the study, the modified poly(PVA: AAc/MgO) composite hydrogel with composition (80:20 vol.%/5 wt%) has higher substitution, macroporous structure and characterized by better performance in swelling and boron uptake capacity than poly(PVA/AAc) hydrogel with composition (80/20 vol.%). The high absorption of boron indicates complex formation via ion exchange and chelation between poly(PVA/AAc/MgO) and boron due to the presence of different moieties provided by acrylic–acrylic, acrylic-PVA, and PVA-PVA.