Tannic acid-assisted fabrication of Fe-Pd nanoparticles for stable rapid dechlorination of two organochlorides

Nanoscale zero valent iron (nZVI) and bimetallic nZVI has been widely applied to remove various contaminants from water and soil, but their activities can be greatly reduced due to the precipitation of the generated Fe ions. Here we adopted tannic acid (TA) as stabilizer to synthesize high activity Fe-Pd nanoparticles (NPs) and scavenger of the generated Fe ions to keep the rapid dechlorination of two organochlorides. Inductively coupled plasma optical emission spectrometry and UV-vis spectroscopy measurements indicated the generated Fe ions were harvested by TA and formed bis- and tris-TA-iron complexes in the dechlorination solution. TA promoted 40-fold and 10-fold increase in dechlorination efficiency of p-chlorophenol and florfenicol attributing to the complexation of Fe ion by TA. This strategy may inspire novel ways to deal with the passivation of nZVI caused by the precipitation of Fe ions and benefits for the developing of longevity and high-efficient nZVI materials.