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Desalination of Complex Multi-Ionic Solutions by Reverse Osmosis at Different pH Values, Temperatures, and
Marko Pranić1,2, Edward M Kimani1,3, P M Biesheuvel1
1European Centre of Excellence for Sustainable Water Technology, Wetsus, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands.
ACS Omega
|August 9, 2021
Summary
Researchers developed a controlled laboratory method using gas control to precisely measure ion retention during reverse osmosis (RO) desalination. This data improves RO models for better desalination performance.
Area of Science:
- Water treatment technologies
- Membrane science
- Physical chemistry
Background:
- Understanding ion behavior in reverse osmosis (RO) is crucial for desalination.
- Existing data on ion retention in multi-ionic solutions often lacks precise control over experimental conditions.
- Accurate data is needed to develop and validate RO ion transport models.
Purpose of the Study:
- To establish a controlled laboratory method for measuring ion retention in multi-ionic solutions during RO.
- To extend and validate existing datasets on ion retention under precisely controlled pH and temperature.
- To investigate the influence of pH, temperature, and cation concentration ratios on ion retention.
Main Methods:
- Utilized N2 and CO2 gas control to precisely set feedwater solution pH.
- Conducted RO experiments with multi-ionic brackish water containing 10 ionic species.
- Varied pH (6.73-7.11) and temperature (15-31 °C), and Na+/Ca2+ ratios.
Main Results:
- Ion retention generally decreased with decreasing pH or increasing temperature.
- The Na+/Ca2+ ratio significantly impacted cation retention more than anion retention.
- A new, validated dataset on ion retention was generated under controlled conditions.
Conclusions:
- The developed gas control method enables precise control of pH for RO desalination studies.
- The improved dataset will enhance the accuracy of RO ion transport models.
- Accurate RO models are vital for the commercial success of desalination technology.
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