Résumé
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•The synergistic effect between HS and the conducting polymers displayed excellent catalytic properties.•Conducting polymers is an electronic mediator to promote the conversion of Fe (III) to Fe (II).•Conjugated systems of PANI and PPy can facilitate the electron transfer during the PS activation.•Protective polymer layers prevented metal ion leaching and enabled pH insensitive persulfate activation.•HS@PANI and HS@PPy catalysts mitigate deactivation and allow facile regeneration.
This study explores new chemical strategies for coating the hematite sand (HS) by conductive polymers to enhance the persulfate activation performance. The highest catalytic activity was due to synergistic effect between the HS and the conductive polymers. In fact, conjugated polymers could act as an activator and electronic mediator to promote the conversion of Fe (III) to Fe (II). Hence, both conductive polymers used (polyaniline and polypyrrole) have been found to provide the necessary electron transfer, thanks to their nitrogen atoms located in their conjugated chains. The radical scavenging experiments assessed by electronic paramagnetic resonance indicated that the studied pathways nature was both a radical and non-radical type. Further, it was found that the protective polymer layers prevented metal ion leaching, mitigate catalyst deactivation, enabled pH insensitive persulfate activation, and increased the chemical stability. This work provides a new innovative way to remove multiple pollutants in wastewater.