A mixture of tea waste (TW), alginate (ALG), and nano iron (Fe) was used to prepare environment-friendly smart beads of composites to decontaminate the water from petroleum oil spillage. ALG and TW represented the hydrophilic pattern incorporation, while the addition of iron nanoparticles resulted in the nanocomposites (ALG/TW/Fe and ALG/Magnetite (Fe3O4)) developing magnetic properties. These properties enable the nanocomposites to be suspended at the interface between oil and water, thus enhancing the efficiency of the smart beads, including their derivatives ALG/TW and ALG/Fe, to decontaminate the water from petroleum oil spillage effectively. The prepared nanocomposite characterisations were carried out thermally by Thermogravimetric analysis (TGA), and their crystallinity was analysed through x-ray diffraction (XRD). These nanocomposites were examined for water absorption capacity (water uptake %WR), exchange ions (ion exchange capacity IEC), and electrical conductivity. The scanning electron microscope (SEM) was used to assess their morphological structure. The created nanocomposites' shape and size were measured using transmission electron microscope (TEM), which ensured that the iron nanoparticles were close to 21.2 nm in size and ovular in shape. The nanocomposites' porosity was appraised through positron annihilation lifetime spectroscopy (PALS). These beads were successfully used for water/oil decontamination with a yield of 99.8% and an efficiency percentage of 99.65%. The ALG/TW/Fe was regenerated by exposing them to a potential gamma irradiation dose of 10 kGy. Regeneration enabled durability for up to ten cycles but with a 48% decrease in their efficiency.