The composite hydrogels were produced using the solution casting method due to the non-toxic and biocompatible nature of chitosan (CS)/polyvinyl alcohol (PVA). The best composition was chosen and crosslinked with tetraethyl orthosilicate (TEOS), after which different amounts of graphene oxide (GO) were added to develop composite hydrogels. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle was used to analyze the hydrogels. The samples were also evaluated for swelling abilities in various mediums. The drug release profile was studied in phosphate-buffered saline (PBS) at a pH of 7.4. To predict the mechanism of drug release, the data were fitted into kinetic models. Finally, antibacterial activity and cell viability data were obtained. FTIR studies revealed the successful synthesis of CS/PVA hydrogels and GO/CS/PVA in hydrogel composite. SEM showed no phase separation of the polymers, whereas AFM showed a decrease in surface roughness with an increase in GO content. 100 µL of crosslinker was the critical concentration at which the sample displayed excellent swelling and preserved its structure. Both the crosslinked and composite hydrogel showed good swelling. The most acceptable mechanism of drug release is diffusion-controlled, and it obeys Fick’s law of diffusion for drug released. The best fitting of the zero-order, Hixson-Crowell and Higuchi models supported our assumption. The GO/CS/PVA hydrogel composite showed better antibacterial and cell viability behaviors. They can be better biomaterials in biomedical applications.

The natural serpentine from Skardu, Pakistan, has been incorporated with magnetite (Fe₃O₄) to form a nanocomposite using a chemical co-precipitation method for the removal of methylene blue (MB) dye. Various techniques such as Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and Vibrating Sample Magnetometer (VSM) have been employed for the characterization. It was found that the composite exhibits sheet-like morphologies, Mg- and Si-rich surfaces, a surface area of 20.8 m²/g, and magnetic properties. The adsorption study showed that the Freundlich isotherm and pseudo-second-order kinetics best described the process with the nanocomposite achieving a 98 % MB removal efficiency, outperforming the pure serpentine. These results highlight the potential of serpentine/Fe₃O₄ nanocomposite as an effective, cost-efficient adsorbent for wastewater treatment applications.