A Review of Diatomaceous Earth as a Bioadsorbent for Pollutants – Part I: Biological precursor, physicochemical characteristics, and standard applications

Diatomaceous earth is a siliceous sedimentary rock formed through the diagenesis of diatom microalgae, resulting in a material with a highly porous three-dimensional microstructure and a large surface area.These physical characteristics, combined with its low chemical reactivity, limited environmental toxicity, and reduced conductivity, have made it a suitable material for water and beverage filtration processes in the food industry, as well as an insecticide and agrochemical carrier in the agricultural industry, and as an additive to improve the mechanical properties of certain construction materials.In addition to these applications, diatomaceous earth is emerging as a natural, eco-friendly adsorbent that is readily available, moderately priced, and easily modified through physicochemical processes to enhance its retention capacity; it is also potentially effective in removing both conventional and emerging contaminants.Given the projected growth in the use of diatomaceous earth-based bioadsorbents for environmental remediation, this review aims to provide a comprehensive overview of diatomaceous earth, from its biological precursor to its notable results in evaluations as an adsorbent for emerging contaminants.Therefore, the first part of this review addresses the essential aspects of diatom, their diagenesis, which enables the production of diatomaceous earth, and its subsequent commercial production.It also addresses the physical and chemical characteristics that enable its conventional use in filtration, agriculture, and construction, which will be discussed briefly.This compendium seeks to consolidate current knowledge in this area, enabling an understanding of the material's prospects and highlighting the potential of diatomaceous earth as an efficient, natural, and eco-friendly adsorbent for environmental remediation.