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Abstract: The toxicity of mercury (Hg) to humans, including damage to the nervous system, is well known. Hg cannot be degraded into non-toxic compounds or other elements. It is released mainly through mining, industries, and fossil fuel combustion. Anthropogenic and natural activities, such as volcanoes, transform elemental Hg (Hg0) into its ionic form [Hg(II)], which bioaccumulates in biota and is biomagnified in the food chain, notably in aquatic environments. This critical report aims to control Hg(II)-ion toxicity through risk assessment, recognition, and removal via high-level waste management. We first discuss successful and up-to-date developments in different techniques, designs and studies that are potentially useful in enhancing the effectiveness of control of Hg(II)-ion toxicity. The key to designing optical nanosensors is to construct chromophore and fluorophore receptors as nanoscale platform scavengers with different functional characteristics (e.g., density, accessibility, and intrinsic mobility), which allow for easy, reliable signaling in continuous monitoring modes. We highlight a technique that depends on the use of engineered mesocage materials that have multidirectional cavities and microsized, particle-like monoliths to control the adsorption/detection of toxic metal ions, especially Hg(II) ions. With regard to proximal sensing, we consider controlled assessment processes that involve the evaluation of intrinsic properties (e.g., signal change, long-term stability, adsorption efficiency, extraordinary sensitivity, selectivity, and reusability). This study provides evidence that miniaturized mesosensor strips can revolutionize consumer and industrial markets with the introduction of ion-sensor strips. [Copyright &y& Elsevier]

The complete remediation of extremely toxic elements, such as cadmium, must be achieved to control the various stages in their life cycles, from mining as virgin ore to using them as consumer and industrial end products, and recycling. Considerable progress has been made in monitoring cadmium ions, but sensors or captors that can simultaneously detect and remove toxic metal ions across a wide range of environments are still greatly needed. This article reviews the tools and the strategies for the environmental remediation of cadmium ions, with special emphasis on state-of-the-art colorimetric sensors. Selective colorimetric sensors based on immobilization of hydrophobic or hydrophilic chromophore molecules into nanosized space cavities have significant advantages because of their dual functionality, namely, early warning “detection” and removal of cadmium ions. This review concludes with a thorough evaluation of emerging challenges and future requirements in monitoring, detecting, and removing cadmium ions from environmental matrices. [ABSTRACT FROM AUTHOR]