Lithium (Li) and water

Seawater contains approximately 0.17 ppm lithium. Rivers generally contain only 3 ppb, whereas mineral water contains 0.05-1 mg lithium per liter. Large amounts of lithium were found in holy water from Karlsbad, Marienbad and Vichy. In solution it is only found as Li⁺ (aq).

In what way and in what form does lithium react with water?

Lithium reacts intensely with water, forming lithium hydroxide and highly flammable hydrogen. The colourless solution is highly alkalic. The exothermal reactions lasts longer than the reaction of sodium and water, which is directly below lithium in the periodic chart.

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2 Li(s) + 2 H₂O -> 2 LiOH (aq) + H₂(g)

At 750^oC lithium reacts with hydrogen to lithium hydride (LiH). The white powder that forms releases hydrogen gas upon later reaction with water, in amounts of 2800 liter per kilogram hydride. As such, lithium can be applied as hydrogen storage.

Solubility of lithium and lithium compounds

Elementary lithium is not very water soluble, but it does react with water.

Lithium compounds such as lithium chloride, lithium carbonate, lithium phosphate, lithium fluoride and lithium hydroxide are more or less water soluble. Lithium hydroxide for example has a 129 g/L solubility.

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Why is lithium present in water?

Lithium is present in many minerals, mostly in amblygonite, petalite, lepidolite and spodumene. Spodumene (LiAlSi₂O₆) is most suitable for commercial purposes.

Lithium is the lightest of all elements and can therefore be applied for many different purposes. It is applied to make aluminium, magnesium and lead alloys lighter and more stable. One of the main applications of lithium is in batteries and accumulators (for industrial transport vehicles).

Lithium carbonate is applied in glass industries and as an additive to glaze, to decrease viscosity of the compounds in question, in order to increase applicability. Other lithium compounds are applied to increase viscosity of oils and fats.

Lithium chloride is a solid with an enormous water holding capacity. It is therefore applied in air-conditioning, and to dry industrial gases. It may also be applied as antifreeze. Other compounds are applied as catalysers and in rocket fuel.

Some lithium compounds may be applied as lubricants, because they can be applied under both high and low temperatures. Lithium can also be applied as a tracer in water flows, and end up in water directly. Lithium is a very successful medicine for the treatment of bipolar syndrome. Lithium hydroxide (LiOH) is applied as air cleansing gas, because it binds carbon dioxide. Finally, lithium is applied to produce tritium (³H), in nuclear weaponry.

What are the environmental effects of lithium in water?

Falls under water hazard class 1, weakly harmful in water. Lithium is not a very big threat to flora and fauna, nor on the mainland, nor in aquatic environments. It is readily absorbed by plants, causing plants to be an indicator of soil lithium concentrations. Lithium is not a dietary mineral for plants, but it does stimulate plant growth. Too much lithium may be toxic. To prevent toxicity, calcium may be added to soils to prevent uptake of lighter minerals. The amount of lithium in plants usually lies between 0.2 and 30 ppm.

The weight of goats that take up lower amounts of lithium appears to increase less rapidly. This may point to a dietary value of lithium.

Lithium exists as two stable and three instable isotopes.

What are the health effects of lithium in water?

The amount of lithium in the human body is approximately 7 mg. Lithium has no known biological use, and it is not readily absorbed by the body. Most lithium is excreted directly upon uptake. Although lithium is not an essential element, it may influence metabolism. Upon oral intake lithium is mildly toxic. Physical tolerance differs between individuals. In the 1940s some patients that applied lithium chloride as a salts replacement died.

Lithium carbonate is applied in psychiatry in doses pretty close to the maximum intake level. At 10 mg/L of blood one is mildly poisoned, at 15 mg/L one experiences confusion and speech impairment, and at 20 mg/L there is a risk of lethality.

Coming in contact with lithium, like other alkali metals, leads to internal blistering.

Which water purification technologies can be applied to remove lithium from water?

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Literature and the other elements and their interaction with water

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