Novel polyaniline/8-hydroxyquinoline composite electrode materials for simultaneous electrochemical removal of heavy metal ions from water resources

Abstract

Herein, polyaniline/8-hydroxyquinoline (PAn-HQ) composites with various monomer feed ratios were developed as novel and efficient electrode materials to remove heavy metal ions including Hg(II), Cd(II), Pb(II), Cu(II), Ni(II), and Zn(II) from water resources. Besides detailed structural, morphological, and thermal stability studies, electrochemical properties of fabricated composites were investigated. Compare with PAn with increasing HQ concentration in the initial feed ratio, more resistant, compact, and sticky structures were observed, as well as excellent mechanical and thermal stability of the composites. Due to significant features of the prepared composites, the considerable removal capacity of heavy metal ions has been achieved through electrodeposition technique. Optimum experimental conditions such as HQ concentration, electrodeposition time, ionic strength, pH, and metal ion concentration were considered. Based on our findings, using 0.06 M HQ concentration, remarkable heavy metal ion removal occurs in an aqueous solution with adjusted pH including 1.0 M KNO3 and 50 mg L−1 initial concentration of metal ion during 24 min electrodeposition. The desorption study by the eluting adsorbent in deionized water at time intervals and adjusted acidic pH values revealed that the initial removal capability of the PAn-HQ composites preserves even after 10 cycles of electrodeposition/desorption. Finally, as-prepared PAn-HQ composites were employed to remove heavy metal ions from a collected real sample from Caspian Sea. The modified PAn-HQ electrodes fabricated via a facile and manageable electrochemical procedure are believed to offer significant adsorption capacity in environmental remediation to remove heavy metal ions.