A Review of Bismuth(III)-Based Materials for Remediation of Contaminated Sites

Abstract

Bismuth­(III)-based materials are uniquely suited for in situ subsurface remedy applications, as they offer many beneficial properties, including high affinity for multiple contaminants, low human and environmental toxicity, low cost, and synthetic availability. This review summarizes the current research trends in targeted development of bismuth materials potentially useful for subsurface remedy applications, with an emphasis on recent advances in understanding of relevant structure–property relationships. While various bismuth mineral phases can provide frameworks for contaminant sequestration, layered crystalline arrangements are particularly promising because of their electronic and spatial flexibility and their ability to accommodate a wide range of negatively charged species. This translates into a high uptake capacity for several recalcitrant colocated contaminants found at legacy nuclear processing sites, including technetium-99, iodine-129, hexavalent chromium (chromate), and uranium, and offers the potential for both in situ and ex situ remediation applications. Layered bismuth minerals are found in nature, and knowledge of their structure informs the targeted design and cost-effective synthesis of the structurally preorganized materials from readily available bismuth sources for remedial applications in soil and groundwater. This comprehensive review highlights the structure, synthesis, and environmental chemistry of Bi-based materials, including the interaction between Bi-based materials and key environmental contaminants, to explore their potential use for remediation. Bismuth oxyhydroxides, containing clusters of [Bi6O4(OH)4]6+ and [Bi6O5(OH)3]5+ surrounded by easily exchangeable anions such as nitrate, are versatile and show the greatest potential for environmental remediation applications. Because of their flexible structural arrangement, they have been shown to sequester electronically and sterically different anionic species, including chromate, pertechnetate, iodate, and uranyl carbonate, even when they are present as comingled contaminants in groundwater and pore water containing other competing anions (e.g., nitrate and carbonate) and in contact with subsurface sediments.

Iodine Removal from Carbonate-Containing Alkaline Liquids Using Strong Base Resins, Hybrid Resins, and Silver Precipitation

“…Liquid phase capture of iodine (as iodide or iodate) is less mature than vapor phase capture, but foundational knowledge is present. ,, The iodide or iodate can be removed through ion exchange, sorption, or precipitation as a low solubility phase (e.g., AgI, K sp = 8 × 10 –17 ). Materials demonstrated for iodine removal include MOF, Ag-based materials, ,− Bi-based materials, − resins (for iodide), − resins (for iodate), , membranes, and layered hydroxides. , However, in nearly all cases, only a single iodine species was the removal target, however, in practicality, these two species commonly coexist with one another. As both I – and IO 3 – are generated in CS, the removal of both must be considered in any such treatment process.…”

A Comprehensive Review on Non‐Trivalent Bismuth‐Based Materials: Structure, Synthesis, and Strategies for Improving Photocatalytic Performance

“…Bi(III)‐based materials occurring in many chemicals form, including oxides, [ 1 ] carbonates, [ 2 ] halides, [ 3 ] tungstate, [ 4 ] molybdate, [ 5 ] vanadate, [ 6 ] ferrite, [ 7 ] etc., possess the advantages of commercially availability, non/low toxicity, ecological friendship, and insensitivity to water and air. [ 8 ] In addition, the orbitals of Bi 6s in Bi (III) hybridize with that of O 2p to form a wider hybridized state, resulting in not only narrow bandgap for enhanced photoabsorption but also highly dispersive band structures for fast charge migration. [ 9 ] And also, the Bi 6s 2 lone electron pair with polarizability could facilitate the separation of photogenerated charge carriers.…”

Review of recent developments in iodine wasteform production

“…Silver saddles have been used during reprocessing at the Hanford site (Raab and Van der Cook, 1970). While Ag is the most commonly investigated element for iodine capture other elements also form low soluble complexes with iodide or iodate, such as Pb (Clark, 1977), Bi (Levitskaia et al, 2022) and lesser tested elements like Gd (Jing-Jing et al, 2020).…”