Grafting of styrene (S) onto biopolymer Sodium Alginate (NaAlg) via free-radical polymerization forming (NaAlg-g-PS), using potassium persulfate K₂S₂O₈ (KPS) as initiator. Fourier-transform infrared spectroscopy (FT-IR) and Proton nuclear magnetic resonance (¹H-NMR) characterized the formed grafted copolymer and scanning electron microscope (SEM) to show changes in the surface morphology of sodium alginate, which occurred due to the grafting process. The effect of various grafting parameters on Sodium Alginate as; Styrene and KPS concentration, the grafting temperature, and grafting time is studied. The adsorption of the grafted copolymer to both cationic dye (Malachite Green) and anionic dye (Congo Red) was investigated. In addition to the effect of the adsorption of the grafted copolymer for toxic heavy metals such as Cu²⁺, Cr⁶⁺, Ni²⁺, and Co²⁺. The order of the metal adsorption by grafted copolymer is Cr⁶⁺ > Cu²⁺ > Co²⁺ > Ni²⁺. The biological activity of the grafted copolymer was shown toward Neisseria gonorrhoeae (Gram-negative), and Bacillus subtilis (Gram-positive) using the agar diffusion method. The obtained results showed excellent improvement in the antibacterial activity of the alginate against Bacillus subtilis and Neisseria gonorrhoeae by the grafting process.

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