A novel route for sensing heavy metal ions in aqueous solution

Abstract

Heavy metal ions are some of the major aquatic pollutants which are held responsible for many ailments as well as undesired effects on flora and fauna. The World Health Organization has prescribed some permissible levels for each of the heavy metal ions. The presence of ions above permissible limits results in toxicity in the aquatic bodies as well as for other water-dependent living organisms. Therefore, it is necessary to make monitoring schemes to keep a check on the concentration of heavy metal ions. Considering this, here we report a unique route to detect heavy metal ions. Through chemical exfoliation, tungsten disulphide (WS2) nanosheets were prepared and drop casted on finger-like Cu electrodes to build the sensing unit. When the sensing unit was treated with heavy metal ions like Cu2+, Co2+, Pb2+, Hg2+, Sn2+ ions, rise in the current across the unit was observed. The concentrations of all the heavy metal ions were the same, i.e., 1 ppm. The maximum current gain was calculated for Cu2+ ions. It was found that the current gain for different ions is different in the voltage range 4–6 V and remains constant except for Cu2+ and Co2+ ions. It is believed that this novel route will pave the way for rapid and simultaneous sensing of different pervasive heavy metal ions in aqueous solutions.