Aşağıda İngilizce özeti verilen çalışmada,

Bentonit ile içme suyunun floritsizleştirilmesi konusunda bir araştırma yapılmıştır. Çalışmada, Etiyopya’da su kaynaklarında elde edilen numunelerde sudaki florit kosantrasyonunun 5 mg/L tespit edildiği bildirilmiştir. Bu oran, florit katılması işleminin yaygın olarak uygulandığı bazı ülkelerdeki oranların çok üstündedir. Örneğin 50 eyaletin 42’sinde bu işlemin uygulandığı belirtilen Amerika’da bile Hastalık Kontrol Merkezlerinin öngördüğü oran 0.7 ile 1.2 mg/L’dir. Suyun floritsizleştirilmesinde çevre dostu bir metod olarak öne çıkan Bentonit kil minerali kullanımı bu araştırmada incelenmiştir. Çalışmada, İtalya’dan temin edilen doğal montmorillonit ve kalsiyum klorür (NaCl2) ile modifiye edilmiş montmorillonit kullanılmıştır. Hazırlanan sodyum florit (NaF) içinde yapılan çalışmada gözlemler yapılmış ve sonuç olarak,

Her iki tip Bentonitin de iyon alışveriş özellikleri sayesinde Floritsizleştirme kabiliyet gösterdiği tespit edilmiştir. Floritleştirme kapasitesinin sırasıyla modifiye edilmiş bentonitte % 45, doğal bentonitte ise % 25 olduğu bulunmuştur.

Defluoridation Of Drinking Water By Using Calcium Loaded Bentonite.
Tewodros Kassa, Alemayehu Abebaw, Malairajan Singanan
Ethiopian Journal of Health Sciences 01/2006; 16(2):101 – 108.
Abstract Background: Endemic fluorosis is a serious problem due to ground water contamination by fluoride. In Ethiopia the distribution of fluorosis extents outside the region of the rift valley to some highland regions. The concentration of fluoride level in rift valley region is above 5.0mg/L in hot springs and other water sources. Hence, it is very much essential to supply safe drinking water to the consumers in these regions. Therefore this study examined, a newer ecofriendly defluoridation method was developed by using bentonite clay minerals. Methods: The experimental solution was prepared by using analytical grade NaF. The concentration of the stock solution was 0.1M. Pure bentonite C obtained from the Department. of Geology, University of Caliary, Italy. The main mineral present in bentonite is montmorillonite, having a formula of (Na, Ca)(Al, Mg) 6(Si4O10) 3(OH) 6.nH2O and modified chemically by using 0.5M CaCl2 solution to enhance the ion – exchange capacity. The chemically modified bentonite formula is (Na, Ca)(Al, Mg) 6(Si4O10) 3(OH) 6. (CaCl2). nH2O. Red clay samples were collected from the local study area (Akaki region). The experiment was conducted during the period 2003. Ion – exchange experiments and adsorption experiments were conducted in batch processes. Finely graded samples of bentonite minerals and red clay were used for this purpose. The free fluoride concentration was determined by using potentiometric method and atomic adsorption spectroscopic method. All the defluoridation experiments were performed at room temperature 22±20C. Results: The ion exchange capacity of the calcium-loaded bentonite was found to be 0.275mmol Ca2+/g of bentonite. The ion exchange capacity of untreated bentonite was 0.013 mmol Ca2+/g. This results indicate that calcium loaded bentonite mineral have good defluoridation capacity. The concentration – time dependency of defluoridation of calcium loaded and raw bentonite mineral showed a good decreasing trend. The rise in free fluoride concentration was due to the influence of dissolved Ca2+ ions, because this ion is originally present on the surface of solid bentonite minerals. After proper stirring, the free fluoride ions precipitated as CaF2 and intern removed from the solutions. Further, the fluoride removal efficiency between calcium loaded, original bentonite showed that the percentage removal of 44 for calcium loaded, and 25 for original bentonite.