Fabrication of a symbiotic polyvinyl alcohol-functionalized NiO/rGO nanoadsorbent for control of bisphenol-a removal

Abstract

Herein, a highly efficient PVA-NiO/rGO nanostructure material (NSMs) is prepared from functionalized reduced graphene oxide (rGO) nanosheets with nickel oxide nanomaterial and polyvinyl alcohol. The as-prepared NSMs adsorbent demonstrated excellent ability to remove bisphenol-A (BPA) from aqueous systems. The engineered PVA-NiO/rGO NSMs was characterized using various analytical tools, such as XRD, EDX, SEM, and EDX mapping. These studies demonstrated the crystalline porous structure of PVA-NiO/rGO NSMs with an average size of 61.5 nm and elemental compositions of 31.9%, 30.8%, and 30.6% for nickel, oxygen, and carbon atoms, respectively. Further, PVA-NiO/rGO nanoadsorbent was used for BPA removal, and the adsorption results showed that the nanoadsorbent exhibited a remarkable 98.6% removal efficiency of BPA in aqueous media under optimized conditions, such as pH 9, an adsorbent dose of 2.5 mg, and an 80 mg L⁻¹ BPA concentration. The adsorption capacity of the nanoadsorbent for BPA was determined to be 104.72 mg g⁻¹. Further, three different isotherm models, i.e., Langmuir, Freundlich, and D–R models, were employed to evaluate the adsorption behavior of the PVA-NiO/rGO nanoadsorbent. The results indicated that the Langmuir isotherm model provided the best fit, with an R² value of 0.9909, suggesting that the surface was homogeneous for the adsorption of BPA. Additionally, the performance of the nanoadsorbent was tested in synthetic and river water samples to assess its practical applications.