Environmental applications of conducting polymers and their composites: adsorption and detection of heavy metal ions

Since the discovery of the conductivity of polyacetylene in the late 1970s, many works have been conducted to synthesize new conductive polymers, characterize their electric and optical properties, and use them in a wide range of applications, including organic electronics, energy storage and biomedical applications. Due to their ease of preparation, lightweight, conductivity, processability, high surface area and chelation properties, conducting polymers and their composites are among the most widely used materials for adsorption and detection of heavy metal ions in aqueous solutions. In this context, this review aims to describe the environmental applications of conducting polymers and their composites. After presenting the properties of conductive polymers, the review describes the principles and factors influencing the adsorption of heavy metal ions by adsorbent materials before describing examples of works using conductive polymers and their composites to remove heavy metal ions from contaminated aqueous solutions. The review then describes the electrochemical techniques used to detect heavy metal ions in aqueous solutions before giving examples of heavy metal ions sensors based on conductive polymers and their composites.