Electrochemical removal of lead ions using paper electrode of polyaniline/attapulgite composites

Polyaniline/attapulgite composites (PANI/ATP) were facilely synthesized via in situ oxidative polymerization of aniline on the surface of ATP. The structure of the resulting composites was characterized by scanning electron microscopy (SEM) and FT-IR spectra. The PANI/ATP was coated on a piece of stiff paperboard to construct a paper electrode, and the electrosorption of Pb(II) was carried out by polarizing the PANI/ATP paper electrode at the potential of –0.3 V. The removal of Pb(II) was mainly attributed to the synergistic effect of physisorption, chemsorption (chelation) and electrostatic interaction, and the effect of electrostatic interaction and chelation is more significant than that of physisorption. Batch experiments were conducted to investigate the effect of applied potential, mass ratio of aniline to ATP, initial concentration, and contact time on the removal of Pb(II). The Freundlich isotherm model fitted the experimental data significantly, and the adsorption kinetics was well described by the pseudo-second-order model. Moreover, electrodesorption experiments were performed to reveal the feasibility for the regeneration of the PANI/ATP paper electrode. All the results indicated that the PANI/ATP could be a promising material for Pb(II) removal.