Preparation and characterization of novel and selective polyacrylamide-graft-poly(2-methoxyaniline) adsorbent for lead removal

Polyacrylamide-graft-poly(2-methoxyaniline) [PACM-gr-P2-MeOANI] was synthesized by the oxidative chemical grafting copolymerization of 2-methoxyaniline (2-MeOANI) onto polyacrylamide (PACM). The grafting was performed in aqueous HCl using ammonium persulfate (APS) as oxidant. The optimum conditions of the grafting based on the yield were achieved. The kinetic grafting copolymerization rate equation was given. Also, the thermodynamic activation parameters of the copolymerization reaction are calculated to be $E_a$ = 23.3833 kJ mol⁻¹, ∆H = 38.7010 KJ mol⁻¹, ∆S = −251507 J mol⁻¹ K⁻¹ and ∆G = 46.1959 kJ mol⁻¹. The obtained polymer samples at optimum conditions were characterized by IR, EM, XRD and TGA to confirm the suggested structure of obtained polymers. The efficiency of the prepared polymeric samples to remove some metal ions from contaminated water was investigated. The obtained graft is a selective adsorbent for Pb(II) ion present in mixture with Mn(II) and Cr(II) ions.