▎ 摘　　要

We have studied the formation of novel hydrogels of conjugate polymer polypyrrole (PPy) and reduced graphene oxide (rGO) for the simultaneous detection of four different metal ions such as Cd2+, Pb2+, Cu2+ and Hg2+. PPy-rGO hydrogel composite exhibits very high surface area of 21.48 m(2) g(-1), which is almost 3.5 times higher than that of PPy (5.89 m(2) g(-1)). The achieved detection limits were much lesser than the world health organisation (WHO) threshold limits and also very less compared to many polymer based heavy metal sensors. (C) 2018 Published by Elsevier B.V.