Efficient removal of Cr(VI) from aqueous solutions using graphene Oxide@Isatin-PVP composite: Synthesis, characterization, and adsorption studies

Abstract

Chromium (VI) is a highly toxic and persistent heavy metal ion often present in industrial effluent, presenting significant hazards to human health and the environment. This work created a new and environmentally benign adsorbent, graphene oxide-isatin-polyvinyl pyrrolidone (GIP), by a simple chemical modification procedure. Graphene oxide (GO) was first functionalized with isatin and then cross-linked with polyvinyl pyrrolidone (PVP) to create a stable, porous composite material with improved surface characteristics. Thorough characterization methods, such as FTIR, SEM-EDX, XRD, and UV–Visible spectroscopy, validated the effective integration of isatin and PVP into the GO framework, yielding a high-surface-area, sponge-like shape. The adsorption efficacy of the GIP composite was assessed for the extraction of hexavalent chromium Cr(VI) from aqueous solutions, with a maximum adsorption capacity of 119.76 ​mg/g. The adsorption behavior conformed to a pseudo-second-order kinetic model, indicating that chemisorptions was the primary process. The results underscore the promise of the GO-Isatin-PVP composite as an effective, sustainable, and economical adsorbent for environmental water remediation purposes.

Keywords

• GO-Isatin-polyvinyl pyrilidone
• Adsorption
• Cr(VI)
• Adsorption efficiency