Removal of Cu(II) from aqueous solutions by novel EDA-functionalized clay nanocomposite fabricated as nanoadsorbents

Present work was conducted to prepare amidoximated based nanocomposites (A-PAMM) could be applied as novel nanoadsorbents for the removal of Cu(II) from aqueous environments. The nanoadsorbents were synthesized via chemical grafting of polyacrylonitrile (PAN) onto surface of ethylenediamine-functionalized montmorillonite (EDA-MMT). The as-synthesized nanoadsorbents were analyzed using Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET). The polymerization of monomer was carried out using 2 wt0% initiator benzoyl peroxide (BPO, C₁₄H₁₀O₄). The prepared A-PAMM nanoadsorbents were further modified with hydroxylamine hydrochloride. The amidoximation process enhances the adsorption capacity of nanocomposites by introducing amidoxime functional groups, which facilitate stronger interactions with Cu(II) through chelation and electrostatic attraction, leading to improved adsorption efficiency. The effects of pH, contact time at different temperature and adsorbent dosage on rate of Cu (II) adsorption was evaluated and the maximum adsorption was obtained with pH 5.4 and contact time of 180 min at 40°C with A-PAMM 5%. The kinetic analysis indicated a pseudo-second-order model for adsorption, with amidoxime-modified samples exhibiting higher rates due to additional amine sites. The Freundlich model best described the adsorption data, particularly for A-PAMM 5%, which had a greater affinity for Cu(II) than EDA-MMT. These findings highlight the effectiveness of amidoxime-modified nanocomposites for Cu(II) removal in wastewater treatment.