Triple layered core-shell ZVI@carbon@polyaniline composite enhanced electron utilization in Cr(vi) reduction

A triple layered core-shell structured zero valence iron@carbon@polyaniline (ZVI@C@PANI) nanocomposite was synthesized and was used to reduce the Cr(vi) in wastewater. The synthesized ZVI@C@PANI was demonstrated to have a great Cr(vi) removal performance with a fast rate and high capacity. ZVI@C@PANI can reduce almost all the hexavalent chromium (Cr(vi)) (1.0 mg L-1) Cr(vi) in 5 min, and has a maximum capacity of 508 mg g(-1). A maximum Cr(vi) removal capacity of 508 mg g(-1) was achieved. The shell layers of C@PANI were demonstrated to be important to improve the electron utilization of the inner ZVI. The PANI shell captured and stored the H+ from the solution, providing an acidic condition on its surface. The carbon layer can adjust the H+ and H-2 transfer in the ZVI@C@PANI. These were disclosed as the mechanisms for the improved electron utilization by this core-shell structured ZVI@C@PANI.