A facile method to synthesize nZVI-doped polypyrrole-based carbon nanotube for Ag(i) removal

The pollution of silver ion (Ag( i )) has become a serious environmental threat and hazard to ecosystem and human health. Thus, the nanoscale zero valent iron (nZVI)-doped polypyrrole-based carbon nanotube (nZVI/CNT) composites were synthesized by a facile method to remove Ag( i ) from wastewater due to the toxicity and scarcity nature of Ag( i ). In this process, Fe 3+ initiated the self-assembly of polypyrrole tubes in the presence of methyl orange, while it also served as an iron source generated nZVI/CNTs by carbothermal reduction method. The nZVI/CNT composites exhibited a homogeneous tubular structure, and the nZVI formed were uniformly dispersed in the nZVI/CNT composites. The nZVI/CNT composites were used as an adsorbent for the removal of Ag( i ) and showed a higher adsorption capacity compared to nZVI and CNTs, with a maximum adsorption capacity of 522.41 mg g −1 . Ag( i ) was adsorbed on nZVI/CNT composites by ion exchange and chelation, where Ag( i ) was reduced to non-toxic Ag due to the redox reaction among pyrrolic-N, nZVI, and Ag( i ). The adsorption process of Ag( i ) on nZVI/CNT composites was dominated by monolayer adsorption. According to our results, nZVI/CNT composites can be used as economical treatment for wastewater containing Ag( i ).