Selective adsorption towards heavy metal ions on the green synthesized polythiophene/MnO2 with a synergetic effect

Selective adsorption towards heavy metals from the industrial wastewater is of great value. Here, we developed a green synthetic strategy to acquire a polythiophene (PTh)/MnO2 composite in the aqueous medium. The produced core-shell composite, which featured abundant sulfurs and hydroxyls, provided a platform for the effective heavy metal ion capture, resulting in a rapid adsorption equilibrium within 30 min, and in novel adsorption capacities of 82.10, 30.72 and 60.79 mg g(-1) for Pb2+, Zn2+ and Cu2+, respectively. It also showed developable selectivity towards these heavy metal ions, which could be tuned by the core MnO2 , with a competition factor order of P(1.22, Ph2+)similar to P(1.02, Zn2+)>> P(0.508, Cu2+). We showed that, through experiments, characterizations and DFT calculation, this selectivity resulted from its synergetic self-doping nature between PTh and MnO2, by which the PTh would protect hydroxyls from being associated with H+ before adsorption, enabling hydroxyls catch heavy metals in a much efficient and selective manner. Moreover, this self-doping nature allowed our composite to be robustly recycled for more than five cycles through a simply acid-base treatment. The provided design principle for the task-specific adsorbent herein would contribute to address challenges concerning heavy metal selective capture in the environmental field.

Automated summary

In this study, we developed a green synthetic strategy to obtain a polythiophene (PTh)/MnO2 composite with high selectivity for heavy metal adsorption. By adjusting the core-shell structure and core MnO2, the composite exhibited efficient adsorption of heavy metal ions. Through experiments and calculations, it was found that this selectivity was due to the synergetic self-doping nature between PTh and MnO2, allowing for robust recycling of the composite in the environment.