Mercury recycling technologies in its' end-of-life management: a review

Mercury (Hg) is a naturally occurring chemical found in rock and coal deposits that can exist in various forms, including elemental Hg, inorganic Hg compounds, methylmercury, and other organic compounds. Exposure to Hg, primarily inorganic Hg, can have severe environmental and occupational hazards and harm human health. Therefore, it is crucial to understand the complex natural transformations and cyclic environmental processes of Hg and its impact on human health and the ecosystem. Both natural and human activities are mainly responsible for the Hg cycles in the environment. Combustion of fossil fuel and subsequent smelting activities are the primary sources from nature for the Hg cycles, while human activities like industrial processes and the use of products containing mercury also contribute to Hg in the environment. These sources ultimately release elemental Hg into the environment, and this Hg vapor can stay in the atmosphere for years and spread throughout the environment via various media. Besides, the whole process repeats and completes the Hg cycle. This review provides detailed knowledge of Hg cycles in the environment, proper end-of-life management of mercury-contained products, and the most up-to-date compilation of Hg recycling technologies, emphasizing the importance of proper Hg waste management. The study also emphasizes the need for a clear understanding of the relationship between local conditions and Hg levels in the environment to forecast Hg concentrations and their ability to be absorbed by living matter. The study also highlights the significance of suitable collection and recovery of Hg waste to prevent its improper disposal, which may lead to contamination of the air, rivers, lakes, and drinking water, thus increasing the risk to the environment and human health.