Impacts of orthophosphate–polyphosphate blends on the dissolution and transformation of lead (II) carbonate
Abstract Orthophosphate–polyphosphate blends are commonly used to control lead release into drinking water, but little is known about how they interact with lead corrosion scale. Conventional corrosion control practice assumes that orthophosphate controls lead release by forming insoluble Pb-phospha...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2022-10-01
|
| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-022-22683-2 |
| _version_ | 1828316857649594368 |
|---|---|
| author | Javier A. Locsin Benjamin F. Trueman Evelyne Doré Aaron Bleasdale-Pollowy Graham A. Gagnon |
| author_facet | Javier A. Locsin Benjamin F. Trueman Evelyne Doré Aaron Bleasdale-Pollowy Graham A. Gagnon |
| author_sort | Javier A. Locsin |
| collection | DOAJ |
| description | Abstract Orthophosphate–polyphosphate blends are commonly used to control lead release into drinking water, but little is known about how they interact with lead corrosion scale. Conventional corrosion control practice assumes that orthophosphate controls lead release by forming insoluble Pb-phosphate minerals, but this does not always occur, and under certain conditions, phosphate blends may increase lead release. Here, we used continuously-stirred tank reactors to compare orthophosphate–polyphosphate blends with orthophosphate on the basis of lead (II) carbonate dissolution and transformation at environmentally relevant phosphate concentrations. Three model polyphosphates—tripoly-, trimeta- and hexametaphosphate—were used. Hexametaphosphate was the strongest complexing agent (1.60–2.10 molPb/molPolyphosphate), followed by tripolyphosphate and trimetaphosphate (1.00 and 0.07 molPb/molPolyphosphate, respectively. At equivalent orthophosphate and polyphosphate concentrations (as P), orthophosphate-trimetaphosphate had minimal impact on lead release, while orthophosphate-tripolyphosphate increased dissolved lead. Orthophosphate-hexametaphosphate also increased dissolved lead, but only over a 24-h stagnation. Both orthophosphate-tripolyphosphate and orthophosphate-hexametaphosphate increased colloidal lead after 24-h. Increasing the concentrations of hexameta- and tripoly-phosphate increased dissolved lead release, while all three polyphosphates inhibited the formation of hydroxypyromorphite and reduced the phosphorus content of the resulting lead solids. We attributed the impacts of orthophosphate–polyphosphates to a combination of complexation, adsorption, colloidal dispersion, polyphosphate hydrolysis, and lead mineral precipitation. |
| first_indexed | 2024-04-13T17:19:47Z |
| format | Article |
| id | doaj.art-cdf86a34d1ba463ebf6ad42a6e07830d |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-04-13T17:19:47Z |
| publishDate | 2022-10-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-cdf86a34d1ba463ebf6ad42a6e07830d2022-12-22T02:38:01ZengNature PortfolioScientific Reports2045-23222022-10-0112111510.1038/s41598-022-22683-2Impacts of orthophosphate–polyphosphate blends on the dissolution and transformation of lead (II) carbonateJavier A. Locsin0Benjamin F. Trueman1Evelyne Doré2Aaron Bleasdale-Pollowy3Graham A. Gagnon4Department of Civil and Resource Engineering, Centre for Water Resources Studies, Dalhousie UniversityDepartment of Civil and Resource Engineering, Centre for Water Resources Studies, Dalhousie UniversityDepartment of Civil and Resource Engineering, Centre for Water Resources Studies, Dalhousie UniversityDepartment of Civil and Resource Engineering, Centre for Water Resources Studies, Dalhousie UniversityDepartment of Civil and Resource Engineering, Centre for Water Resources Studies, Dalhousie UniversityAbstract Orthophosphate–polyphosphate blends are commonly used to control lead release into drinking water, but little is known about how they interact with lead corrosion scale. Conventional corrosion control practice assumes that orthophosphate controls lead release by forming insoluble Pb-phosphate minerals, but this does not always occur, and under certain conditions, phosphate blends may increase lead release. Here, we used continuously-stirred tank reactors to compare orthophosphate–polyphosphate blends with orthophosphate on the basis of lead (II) carbonate dissolution and transformation at environmentally relevant phosphate concentrations. Three model polyphosphates—tripoly-, trimeta- and hexametaphosphate—were used. Hexametaphosphate was the strongest complexing agent (1.60–2.10 molPb/molPolyphosphate), followed by tripolyphosphate and trimetaphosphate (1.00 and 0.07 molPb/molPolyphosphate, respectively. At equivalent orthophosphate and polyphosphate concentrations (as P), orthophosphate-trimetaphosphate had minimal impact on lead release, while orthophosphate-tripolyphosphate increased dissolved lead. Orthophosphate-hexametaphosphate also increased dissolved lead, but only over a 24-h stagnation. Both orthophosphate-tripolyphosphate and orthophosphate-hexametaphosphate increased colloidal lead after 24-h. Increasing the concentrations of hexameta- and tripoly-phosphate increased dissolved lead release, while all three polyphosphates inhibited the formation of hydroxypyromorphite and reduced the phosphorus content of the resulting lead solids. We attributed the impacts of orthophosphate–polyphosphates to a combination of complexation, adsorption, colloidal dispersion, polyphosphate hydrolysis, and lead mineral precipitation.https://doi.org/10.1038/s41598-022-22683-2 |
| spellingShingle | Javier A. Locsin Benjamin F. Trueman Evelyne Doré Aaron Bleasdale-Pollowy Graham A. Gagnon Impacts of orthophosphate–polyphosphate blends on the dissolution and transformation of lead (II) carbonate Scientific Reports |
| title | Impacts of orthophosphate–polyphosphate blends on the dissolution and transformation of lead (II) carbonate |
| title_full | Impacts of orthophosphate–polyphosphate blends on the dissolution and transformation of lead (II) carbonate |
| title_fullStr | Impacts of orthophosphate–polyphosphate blends on the dissolution and transformation of lead (II) carbonate |
| title_full_unstemmed | Impacts of orthophosphate–polyphosphate blends on the dissolution and transformation of lead (II) carbonate |
| title_short | Impacts of orthophosphate–polyphosphate blends on the dissolution and transformation of lead (II) carbonate |
| title_sort | impacts of orthophosphate polyphosphate blends on the dissolution and transformation of lead ii carbonate |
| url | https://doi.org/10.1038/s41598-022-22683-2 |
| work_keys_str_mv | AT javieralocsin impactsoforthophosphatepolyphosphateblendsonthedissolutionandtransformationofleadiicarbonate AT benjaminftrueman impactsoforthophosphatepolyphosphateblendsonthedissolutionandtransformationofleadiicarbonate AT evelynedore impactsoforthophosphatepolyphosphateblendsonthedissolutionandtransformationofleadiicarbonate AT aaronbleasdalepollowy impactsoforthophosphatepolyphosphateblendsonthedissolutionandtransformationofleadiicarbonate AT grahamagagnon impactsoforthophosphatepolyphosphateblendsonthedissolutionandtransformationofleadiicarbonate |