Natural Zeolites for elimination of Fluoride

Elimination of Fluoride from Drinking Water in the Rift Valley using Natural ZeolitesZeolites and fluoride-rich groundwaters are both usually associated to volcanic regions, and hence in this work we study natural zeolites as fluoride-adsorbents in order to develop a cheap and locally-available fluorosis mitigation technology. Dental and skeletal fluorosis (fluoride poisoning) is endemic in the Ethiopian Rift Valley including some parts of Gambela Regional State.

Children in particular are vulnerable to excessive fluoride intake because their permanent teeth are still being formed. In the Ethiopian Rift Valley, 41% of the drinking-water sources have a fluoride concentration exceeding 1.5 mg/L, and food ingredients and food prepared with local water may also be a major fluoride source. Studies indicate that more than 14 million people in Ethiopia may be at risk of dental and skeletal fluorosis.

Despite several attempts to reduce the total fluoride concentration in potable water using simple and low-cost defluoridation methods for use at the household level, the mitigation activities of fluorosis in Ethiopia and in Africa at large are still at the initial stages. Our project offers a complementary approach to the reduction of water contaminants in the Rift Valley area by using natural local resources, i.e. natural zeolites.

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Zeolites are a vast natural resource in Ethiopia that remains unexploited due lack of scientific knowledge and available manpower with a geology background and means to initiate the systematic exploitation of this resource.

Natural zeolites have a volcanic origin and belong to the family of hydrated aluminosilicates and have a microporous structure that can accommodate a wide variety of cations such as sodium, potassium and magnesium.

These cations can easily be interchanged by others in what is one of the main applications of this kind of minerals: ionic exchange. Some of the most well known applications of zeolites in this area include the selective treatment of sewage waters, extraction of ammonia, odour control, heavy metal extraction from nuclear, mining and industrial waste, soil conditioning for agricultural uses and even as an animal feed stock.

Based on these grounds, the main objective of the present work is to test the potential use of several samples of naturally-occurring zeolites of the country in fluoride removal from water in the Riff Valley area in an attempt to mitigate fluorosis problems by using locally-available and so far unexploited materials, thus developing a sustainable cost-effective fluoride-removal local technology.

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