Detection and removal of heavy metal ions: a review

In aqueous systems, heavy metal ions, when present in excess than permissible limits, are dangerous for human beings and aquatic life. Heavy metals cannot be degraded. Rather, they accumulate in living organisms either directly or through the food chain. Inside the body, metal ions can be converted to more toxic forms or can directly interfere with metabolic processes. As a result of metal toxicity, various disorders and damage due to oxidative stress triggered by metal ions have been witnessed. Toxic effects of metallic pollution coupled with the need of pure water for the survival and sanitation have thus prompted researchers to take every possible step to uphold the quality of water. In this regard, various strategies have been developed for the detection and the removal of metal ions from aqueous systems. Here we review metal-free water and methodologies used for rapid detection at low levels. Also, the application of benign materials and methods for metal removal from aqueous systems is detailed. Electrochemical methods, especially stripping and cyclic voltammetry, are commonly used methods for detection, while adsorption and ion exchange methods are quite effective for removal.