In this study, cryogel nanocomposite based on poly (vinyl alcohol) (PVA) in situ formed zinc oxide nanoparticles (ZnO NPs) in the presence of fulvic acid (FA) was fabricated via repeated freeze-thawing method. Fourier transformed infrared spectroscopy (FTIR) was used for chemical elucidation of the prepared samples. The surface morphologies of bare PVA and PVA cryogel–ZnO nanocomposites were evaluated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The SEM results demonstrated that synthesized cryogels illustrated porous morphology whereas TEM images confirmed the existence of nearly spherical and well-distributed ZnO NPs with diameter less than 50 nm. All related reflections for crystal structure of ZnO NPs were shown by X-ray diffraction (XRD) results. Thermal stability of synthesized hydrogels was investigated using TGA and DSC analyses. The effect of various salt solutions was studied for swelling behavior of prepared nanocomposites. PVA/FA/ZnO hydrogel nanocomposite was also tested for drug delivery activities for controlled release of FA. Moreover, the kinetic investigations showed the best fit with Korsmeyer–Peppas model with Fick’s diffusion as the drug
