Preparations and applications of organic conducting polymers/graphene composites in heavy metal ion sensing: a review

This review focuses on the trends and challenges, over the last ten years, in the development of electrochemical sensors based on organic conducting polymers and graphene composites for the determination of trace heavy metal ions in water. Some of these materials taken alone still have significant limitations for the selective and ultrasensitive detection of target species. Hence, it has become crucial to develop new composite materials able to overcome these limitations and to improve the sensitivity to heavy metal ions. The properties resulting from the combination of these two types of materials, which increased the electrochemical performance by offering many advantages such as improvement of catalytic activity and conductivity, fast electron transfer kinetics, large surface area and high sensitivity were reviewed. This review also presents in detail various methods (chemical, electrochemical and hydrothermal) used to prepare composites and characterization methods (spectroscopic, microscopic, electrochemical, etc.). The applications of these composites in electroanalysis of heavy metal ions have been discussed and summarized. Also, electrochemical detection methods, particularly those called "Anodic Stripping Voltammetry " have been explained and their uses in the detection of heavy metal ions in natural water have been highlighted, and the results provided.