Adsorption of fluoride on goethite surfaces-implications on dental epidemiology

Ferrihydrite reactivity toward carbon dioxide

“…Specifically, we show vibrational data associated with ferrihydrite that had been exposed to F À bearing aqueous solutions. Prior research has shown that F À undergoes substitution reactions with hydroxyl groups on oxide surfaces [47]. Vibrational data is shown here that demonstrates that by using this chemistry the free OH group associated with ferrihydrite can be replaced with fluoride and that this substitution reaction allows us to better support our surface complexation model.…”

Evaluating the effectiveness of a hybrid sorbent resin in removing fluoride from water

“…The plots were found liner with > 0.98 correlation coefficients that showed that Langmuir model was applicable to the present study. This means that the F adsorption is in the form of monolayer coverage on the surface of the adsorbent (Jinadasa et al, 1993). In this study, it has been demonstrated that Lewatit FO 36 can remove fluoride with 61% efficiency where F concentration is less than 4 mg/L.…”

“…The highest adsorption of 61 % was observed at pH = 5.5. F adsorption was clearly affected by pH of the solution and decreased with increasing pH (Jinadasa et al, 1993;Ayoob et al, 2008;Kumar et al, 2009) .…”

“…Iron and aluminum oxides such as GFH (Kumar et al, 2009), goethite (Jinadasa et al, 1993), activated alumina (Hiemstra and Van Riemsdijk, 1999;Ku and Chiou, 2002) and alumina cement granules (Tang et al 2009) play an important role in removal of anions from aqueous solutions.…”

Fluoride adsorption onto an acid treated lateritic mineral from Kenya: Equilibrium studies

“…Chen et al (2010) has indicated that F adsorption onto FeOH-based adsorbents proceeds by surface exchange replacement of OH groups by F ions or by inner sphere complexation with FeOH surfaces but a more extensive examination of mechanistic behaviour of FeOH adsorbents has been provided by Waychunas et al (2005). However, while fluoride adsorption onto low cost soils and clay adsorbents including: fly ash (Chaturvedi et al, 1990) siderite (Liu et al, 2010), attapulgite (Zhang et al, 2009), coal (Borah and Dey, 2009), Boehmite (Ramos et al, 2008), goethite (Jinadasa et al, 1993) kaolinite (Gogoi an Baruah, 2008), bentonite (Karthikeyan et al, 2005), zeolites (Onyango et al, 2004), calcite (Min et al, 1999), and ceramic materials (Chen et al, 2010) have been extensively studied, many Kenyan clays and soils have not yet been assessed for their potential use as F sorbents. This study, based around Gilgil in Nakuru County of Kenya, therefore, evaluated the capacity of an Fe-rich lateritic clay minerals from Kenya for F removal from aqueous solution.…”