Ferrate(VI) pretreatment of water containing natural organic matter, bromide, and iodide: A potential strategy to control soluble lead release from PbO2(s)

Lead dioxide (PbO2(s)) is a corrosion product of lead-containing plumbing materials in water distribution pipelines. The presence of reductants in water could cause the release of soluble lead (mainly Pb(II)) from PbO2(s). Lead in drinking water is detrimental to public health. This paper presents the first application of ferrate ((FeO42-)-O-VI, Fe(VI)) to decreasing the generation of soluble lead in water containing PbO2(s) and common reducing constituents (e.g., natural organic matter (NOM), iodide (I-), and bromide (Br-)) at different pH conditions (i.e., 6.0, 7.0, and 8.0). The released soluble lead from PbO2(s) was found to be dominantly controlled by NOM inwater, via the redox dissolution of PbO2(s) and the reduction of PbO2(s) by reducing moieties of NOM. The feasibility of both processes increased when pH decreased. The I- and Br- in water played minor roles in generating soluble lead. Fe(VI) reacted with reducing functional groups of NOM, as determined by C-13 nuclear magnetic resonance spectroscopy. Water pretreatment with Fe(VI) inhibited the reaction of NOM with PbO2(s) and therefore, caused lower soluble lead concentrations compared to water samples without Fe(VI) treatment. This study indicates that Fe(VI) pretreatment is a potential approach to controlling soluble lead in drinking water. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study introduces the use of Fe(VI) to reduce the generation of soluble lead in water containing corrosion product PbO2(s). Soluble lead release was found to be mainly controlled by natural organic matter in water, with reduced feasibility at lower pH values. Fe(VI) pretreatment showed potential in inhibiting the reaction of NOM with PbO2(s) and decreasing soluble lead concentrations in water.