Effective nanomembranes from chitosan/PVA blend decorated graphene oxide with gum rosin and silver nanoparticles for removal of heavy metals and microbes from water resources

Abstract

Fabricating an effective bio-adsorbent based on functional spots can surely be able to eliminate numerous of heavy metals and pathogens from contaminated water resources. Thus, this study aimed to fabricate depollution bionanomembranes based on amalgamated the decorated graphene oxide (GO) with antibacterial natural rosin and silver (Ag) NPs inside chitosan (CS)/polyvinyl alcohol (PVA) blend by the solvent-casting route. The nanostructure of prepared GO nanoplatelets and its decoration are investigated by X-ray diffraction (XRD). Various ratios from decorated GO (i.e., 1, 2 and 3 wt.%) are utilized to prepare CS/PVA nanomembranes. The structure and surface topography of casted nanomembranes are analyzed by XRD and SEM. The obtained outcomes revealed that the use of decorated GO, especially at 2 wt.%, increased the tensile strength to ∼ 48 MPa compared to the unfilled blend (33 MPa). Other investigations such as thermal stability and antibacterial properties are also conducted on the casted CS/PVA nanomembranes. Moreover, depollution of heavy metals is explored through adsorption into the polymeric membranes at ambient temperature and pH 4–6. The gotten results supported that CS/PVA-3% NPs membrane possessed higher adsorption property towards the selective metal ions (i.e., 85–99.7% depending on the metal ion type) compared to other nanomembranes. However, the tensile strength achieved for the nanomembrane containing 2 wt.% nanoplatelets. The impact of pH, temperature, contacting time, and bacterial colony counting on CS/PVA-3% NPs is also studied, in addition to the recovery and reusability of adsorbent. Furthermore, kinetic and isothermal models are suggested to depict the adsorption efficacy of CS/PVA-3% NPs membrane. The obtained data showed that CS/PVA-3% membrane is a promising candidate to be utilized for removal of heavy metals and biological species from water resources for irrigation and agricultural applications.