Photocatalytic treatment of organoselenium in synthetic mine-impacted effluents

27 October 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Biological selenium reduction processes are commonly employed as the best available technology (BAT) for selenium removal, however, as a by-product they produce trace amounts of organoselenium compounds with orders of magnitude greater bioaccumulation potential and toxicity. Here we assessed buoyant photocatalysts (BPCs) as a potential passive advanced oxidation process (P-AOP) for organoselenium treatment. Using a synthetic mine-impacted water solution, spiked with selenomethionine (96 µg/L) as a representative organoselenium compound, photocatalysis with BPCs fully eliminated selenomethionine to <0.01 µg/L with conversion to selenite and selenate. A theoretical reaction pathway was inferred, and a kinetics model developed to describe the treatment trends and intermediates. Given the known toxic responses of Lepomis macrochirus and Daphnia magna to organoselenium, it was estimated that photocatalysis could effectively eliminate organoselenium acute toxicity within a UV dose of 8 kJ/L (1-2 days solar equivalent exposure), by transformation of selenomethionine to less hazardous oxidized Se species. Solar photocatalysis may therefore be a promising passive treatment technology for selenium-impacted mine water management.


passive treatment
mine water

Supplementary materials

Supporting Information
The supporting information contains diagrams of the apparatus used for the treatment experiments, additional data comparing a photolysis (UV only) control to photocatalysis, nitrogen balance data following photocatalysis, and the kinetics model derivation and parameters proposed in this work.


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