A review on monolithic remediators for mercury pollution control in industrial flue gas and effluents

Abstract

Elemental mercury (Hg⁰) and oxidized mercury (Hg²⁺), accounting for more than 95 % of anthropogenic Hg emissions, must be effectively removed from industrial flue gases and effluents to avoid their pollutive and hypertoxic effects. Removing mercury from industrial sources by monolithic remediators is a highly efficient and practical technique to this end, with some typical monoliths stepping toward commercialization. Compared to powdered ones, monolithic remediators merit for their improved recyclability, lower environmental risks, and less detrimental effects on the operation of flue gas cleaning facilities. Considering the importance of monolithic remediators in promoting the development of mercury detoxification techniques, this work for the first time reviewed previous research in related fields. The monolithic mercury remediators are categorized into eight groups based on the properties of substrates, i.e., granular activated carbons, carbon aerogels, silica aerogels, chalcogels, honeycomb ceramics, sponges, sulfur polymers and other monolithic composites. In this review, the synthetic methods of those monolithic remediators used for mercury pollution control were scrutinized, their mercury removal performances were summarized, and the mercury adsorption mechanisms were discussed. The aim is to bridge the previous achievements and future development of monolithic mercury remediators, hence guiding the design of more effective monolithic materials used for efficient mercury removal from industrial flue gases and effluents.