Water has become increasingly prominent as a source of various precious substances such as lithium, phosphorus, nitrogen, and potassium. Lithium is especially important because this substance is used in the production of batteries. An international team of scientists, including scientists from Leeuwarden's Wetsus Research Institute and Wageningen University Research Institute (WUR), has been working on a technique that makes it possible to separate various substances from water.

The research team led by Lewis Desmidt (part of WUR Organic Chemistry) published an article on this issue yesterday in the famous "Energy and Environmental Science" magazine. In addition to Dutch experts, researchers from Seoul National University, Yale University, Technion and Tsinghua University also participated in the meeting.

Approximately 70% of the earth's surface is covered by water, most of which exists in the ocean, but this is salt water and is not suitable for human consumption. Fresh water (only 3% of the total) exists in ice sheets and glaciers. Groundwater is usually fresh water, so it can be used. Because fresh water is limited, seawater desalination has become an important technical research direction.

Pure form

This technique is called capacitive deionization (CDI). This is one of the techniques used to desalinate salt water. Scientists use this method to selectively extract ions from water. This is because potassium and phosphorus are composed of ions. Reuse is often just an option when you get your hands on these nutrients in pure form. This makes this technology even more important.

Louis Desmidt explained: "All these theoretical forces are summarized in review with simple formulas and short calculations to illustrate the impact. The calculations show that separation is entirely possible. You must pay close attention to many details, such as the speed at which you achieve separation. ."

Multiple methods

In order to effectively select raw materials, several of these methods may need to be used at the same time. "We expect to have more and more new electrodes and membranes, so that there are more options to improve the selectivity of CDI."

Maarten Biesheuvel of Wetsus added: "As described in the Wageningen publication, a better understanding of the ion selectivity and ion transport of these materials will be a guideline for materials scientists."