Copper(II) removal from the aqueous solution using microporous benzidine-based adsorbent material

In this work, the ability of benzidine-based microporous polymer network as adsorbent for removal of copper(II) species from aqueous solutions was investigated. The designed benzidine-based adsorbent material (BBAM) with high specific surface area was synthesized using phloroglucinol and benzidine monomers with hydrochloric acid catalyst at 180°C for 3 days followed by freeze-drying process. The porosity character of the material was confirmed by SEM analysis and CO₂ adsorption/desorption studies at 0°C. The adsorption efficiency of the BBAM for different metal ions, namely Hg(II), Fe(II), Pb(II), Ni(II), Zn(II) and Cd(II) was experimented, however, a specific sorption behavior against Cu(II) ions was observed. The function of pH and contact time was studied and the highest adsorption capacities for Cu(II) were found as 97% with pH of 4.5 at the end of 300 min. As verified by FTIR and XRD spectral analysis, the sorption mechanism is attributed to the coordination system formed between amino groups in the porous structure and Cu(II) ions. Reusability of the system was also presented by applying six cycles without any significant loss of activity.