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Water 2018, 10(1), 54; doi:10.3390/w10010054

Removal of Hardness from Water Samples by a Carbonation Process with a Closed Pressure Reactor

Ewha Girls High School, 26 Jeongdong-gil, Jung-gu, Seoul 04516, Korea
Carbon Mineralization Center, Climate Change Mitigation and Sustainability Division, Korea Institute of Geosciences and Mineral Resources (KIGAM), 124, Gwahak-ro, Yuseong-gu, Daejeon 34132, Korea
Chemical Engineering Department, Kwangwoon University, 20 Kwangwoon-ro, Nowong-gu, Seoul 01897, Korea
Author to whom correspondence should be addressed.
Received: 15 November 2017 / Revised: 3 January 2018 / Accepted: 8 January 2018 / Published: 10 January 2018
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One of the undesirable characteristics of some ground and natural water sources is hardness. Hard water can cause many problems around the world, including increased scaling on water pipes, boilers, atopic eczema and odd-tasting drinking water. Hardness in natural water is caused by dissolved minerals, mainly calcium and magnesium compounds. According to the Water Quality Association (WQA) and the United States Geological Survey (USGS), hard water is classified based on the Ca2+ and Mg2+ ion concentration in waters, as follows: 0–60 ppm as soft; 61–120 ppm as moderately hard; 121–180 ppm as hard and more than 180 ppm as very hard water. Most water utilities consider a hardness level between 50 and 150 ppm of CaCO3 as publicly acceptable. The present study investigated the effects of a carbonation process on the removal of hardness in different water samples. Currently, a wide variety of hardness removal technologies are available. Among those conventional methods, carbonation is an inexpensive process which can be used for the removal of Ca2+ and Mg2+ ions from hard water. This study measured the hardness levels of 17 different water samples using the ethylene diamine tetra acetic acid (EDTA) method. Among these, Seoul outdoor swimming pool water (140 ppm) samples showed high concentrations of Ca2+ and Mg2+ ions. The hardness of the different water samples was reduced by 40–85% by a carbonation process with a closed pressure reactor for a 5 min reaction time. View Full-Text
Keywords: water hardness; removal; carbonation; closed pressure reactor water hardness; removal; carbonation; closed pressure reactor

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

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Ahn, M.K.; Chilakala, R.; Han, C.; Thenepalli, T. Removal of Hardness from Water Samples by a Carbonation Process with a Closed Pressure Reactor. Water 2018, 10, 54.

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