Rapid and selective removal of Pb ions by electroactive titanium Dioxide/Polyaniline ion exchange film

The slow accumulation of heavy metal in the sediment and aquatic food chain, leads to extremely bad health influence in human body. Most of the traditional adsorption materials have deficient adsorption capacity and selectivity. In this research, the TiO 2 /PANI composite material is synthesized successfully by intercalating 2HT (intercalating agent) and PANI into the interlayer of the TiO 2 nanosheet for the separation of Pb 2+ . During this synthesis process, the layer spacing of TiO 2 /PANI can be controlled precisely by adjusting the concentration of 2HT and PANI. The rapid Pb 2+ uptake/ release process is triggered through turning the redox states of composite film which can leads to the conversion between Ti 4+ and Ti 3+ and the conversion between –OH and -O-Pb covalent bond for maintaining the electrical neutrality. In addition, the directional H + proton migration, fast electronic transporting network and superfast Pb 2+ ion transport path both are benefit for the transmission and uptake of Pb 2+ . As a result, this composite film illustrates ultrahigh uptake capacity (1499.99 mg∙g −1 ) and selectivity (K D  = 15.2 L·g −1 ). It can even treat real wastewater to a level lower than WHO. Hence, this composite film with superior electrochemical performance is a promising material, which could be used for uptake/release of Pb 2+ .