Hardness properties of calcium and magnesium ions in drinking water

The drinking water parameter - water hardness - is defined as the sum of calcium and magnesium ion concentrations. In this study, their precipitation during boiling was investigated, using water of different hardnesses, calcium to magnesium ratios, natural tap and bottled waters. During boiling, pH...

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Main Authors: Yonca Pinar Ingin, Daniel Mahringer, Fatima El-Athman
Format: Article
Language:English
Published: Elsevier 2024-12-01
Series:Applied Food Research
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Online Access:http://www.sciencedirect.com/science/article/pii/S2772502224002105
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author Yonca Pinar Ingin
Daniel Mahringer
Fatima El-Athman
author_facet Yonca Pinar Ingin
Daniel Mahringer
Fatima El-Athman
author_sort Yonca Pinar Ingin
collection DOAJ
description The drinking water parameter - water hardness - is defined as the sum of calcium and magnesium ion concentrations. In this study, their precipitation during boiling was investigated, using water of different hardnesses, calcium to magnesium ratios, natural tap and bottled waters. During boiling, pH value, conductivity, and calcium and magnesium concentrations were measured. Further, the morphology and composition of precipitates were analyzed. Boiling tests with durations of 30 min showed only a decrease of calcium concentration by precipitation. Longer boiling of water with a high proportion of magnesium showed decreasing magnesium concentrations once the calcium precipitation was completed. Calcium carbonate precipitated as calcite and aragonite crystals with aragonite needles occurring in the presence of high magnesium concentrations. Magnesium hydroxide formed during precipitation was identified as hydromagnesite crystals with different crystallization morphologies. Unexpectedly, for a water with low and equimolar concentrations of calcium and magnesium only magnesium precipitated at the relatively low pH 8.7. In summary, calcium ions in drinking water are evaluated as being of considerably higher relevance for the hardness properties than the magnesium ions. However, the precipitation of both minerals depends on their concentrations and ratio as well as on the pH value and the water matrix.
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spelling doaj-art-2d36b87fa3654e60aec5885ecd2b01f12025-08-20T02:49:00ZengElsevierApplied Food Research2772-50222024-12-014210060010.1016/j.afres.2024.100600Hardness properties of calcium and magnesium ions in drinking waterYonca Pinar Ingin0Daniel Mahringer1Fatima El-Athman2Technische Universität Berlin, Department of Environmental Science and Technology, Chair of Water Quality Engineering, Straße des 17. Juni 135, 10623 Berlin, GermanyGerman Environment Agency, Schichauweg 58, 12307 Berlin, Germany; Corresponding author.Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655 Hannover, GermanyThe drinking water parameter - water hardness - is defined as the sum of calcium and magnesium ion concentrations. In this study, their precipitation during boiling was investigated, using water of different hardnesses, calcium to magnesium ratios, natural tap and bottled waters. During boiling, pH value, conductivity, and calcium and magnesium concentrations were measured. Further, the morphology and composition of precipitates were analyzed. Boiling tests with durations of 30 min showed only a decrease of calcium concentration by precipitation. Longer boiling of water with a high proportion of magnesium showed decreasing magnesium concentrations once the calcium precipitation was completed. Calcium carbonate precipitated as calcite and aragonite crystals with aragonite needles occurring in the presence of high magnesium concentrations. Magnesium hydroxide formed during precipitation was identified as hydromagnesite crystals with different crystallization morphologies. Unexpectedly, for a water with low and equimolar concentrations of calcium and magnesium only magnesium precipitated at the relatively low pH 8.7. In summary, calcium ions in drinking water are evaluated as being of considerably higher relevance for the hardness properties than the magnesium ions. However, the precipitation of both minerals depends on their concentrations and ratio as well as on the pH value and the water matrix.http://www.sciencedirect.com/science/article/pii/S2772502224002105HardnessCalciumMagnesiumPrecipitationConductivityDissolved organic carbon
spellingShingle Yonca Pinar Ingin
Daniel Mahringer
Fatima El-Athman
Hardness properties of calcium and magnesium ions in drinking water
Applied Food Research
Hardness
Calcium
Magnesium
Precipitation
Conductivity
Dissolved organic carbon
title Hardness properties of calcium and magnesium ions in drinking water
title_full Hardness properties of calcium and magnesium ions in drinking water
title_fullStr Hardness properties of calcium and magnesium ions in drinking water
title_full_unstemmed Hardness properties of calcium and magnesium ions in drinking water
title_short Hardness properties of calcium and magnesium ions in drinking water
title_sort hardness properties of calcium and magnesium ions in drinking water
topic Hardness
Calcium
Magnesium
Precipitation
Conductivity
Dissolved organic carbon
url http://www.sciencedirect.com/science/article/pii/S2772502224002105
work_keys_str_mv AT yoncapinaringin hardnesspropertiesofcalciumandmagnesiumionsindrinkingwater
AT danielmahringer hardnesspropertiesofcalciumandmagnesiumionsindrinkingwater
AT fatimaelathman hardnesspropertiesofcalciumandmagnesiumionsindrinkingwater