Hard water can be softened by atomization

• Published in: Food Science and Technology Research Vol. 29; no. 6; pp. 465 - 474
• Main Authors: Kubo, Kazuhiro, Kasumi, Mayu, Yamashita, Takatoshi
• Format: Journal Article
• Language: English
• Published: Tsukuba Japanese Society for Food Science and Technology 01.01.2023; Japan Science and Technology Agency
• Subjects: atomization; Atomizing; Bubbles; calcium carbonate; Calcium ions; Electrical conductivity; Electrical resistivity; fine bubbles; hard water; spray; Water hardness; Water softening
• ISSN: 1344-6606; 1881-3984
• DOI: 10.3136/fstr.FSTR-D-23-00059

Hard water is softened because its use in everyday life can cause various problems in the living environment. However, existing water-softening methods have a number of drawbacks. Here we examined a new water-softening method involving atomization. Three concentrations of calcium-based synthetic hard water and a commercial natural hard water were prepared. Each hard water was sprayed into the atmosphere at 1 MPa from an atomization nozzle and then collected. Part of the collected water was recirculated, and the atomization treatment was continued. After the treatment, a white precipitate and fine bubbles were generated, the Ca2+ concentration and electrical conductivity decreased, and the pH increased. Then over time, the white precipitate increased slowly and the Ca2+ concentration decreased until finally it almost fell within the recommended range. This water-softening phenomenon was thought to be due to expansion of the gas-liquid interfacial area and generation of fine bubbles with atomization. This method is extremely simple and expected to show high versatility.