Photoelectrochemical detection of toxic heavy metals

Abstract

Toxic heavy metals in air, soil, and water are global problems that are a growing threat to the environment. Trace metal determination is currently done by expensive separation techniques which include inductively coupled plasma (ICP) and cold vapor atomic fluorescence spectroscopy (CVAFS). These techniques are sensitive and accurate in their detection of metals in the environment but are expensive to maintain, immobile and require sample preparation. Immobilisation of cation-selective flourophores on various substrates introduced the possibility for portable and on-site instant verification of heavy metal pollutants. In this work, the favorable properties of the mercury-sensitive fluorescent molecule, Rhodamine 6G hydrozone derivative (RS), were combined with titanium dioxide (TiO2) and polyaniline (PANI) to construct an electrochemical cell that is capable of conducting a current in the presence of white light and inorganic mercury (Hg2+). A prototype photoelectrochemical mercury detector (PEMD) was constructed and investigated as a possible inexpensive tool for on-site prescreening of Hg2+ in surface water.