Defluoridation from aqueous solution by lanthanum hydroxide

Fluoride removal in water by a hybrid adsorbent lanthanum–carbon

“…Na and H.J. Park [27], when they used lanthanum hydroxide as adsorbent for the removal of fluoride. However, high concentrations of co-existing anions (P50 mg L À1 of each anion) showed a noticeable decrease around 58% on the fluoride adsorption capacity.…”

“…For instance, colloidal lanthanum has been used with excellent results to remove fluoride from water, but its application in water treatment systems is very challenging, because it would be difficult to recover after fluoride adsorption at the end of treatment. [37,22,27,32]. Because of this, the research's objective was to anchor lanthanum oxyhydroxides onto a commercial granular activated carbon (GAC) to remove fluoride from water, which to the best of our knowledge, has not been reported.…”

A review on adsorbents used for defluoridation of drinking water

“…The fluoride ions would have to overcome electrostatic forces as there would be a higher density of negative charge very close to the surface, hence greater electrostatic repulsion (Streat et al 2008). Lanthanum oxide and hydroxide, CA, Ti-Almetal oxide, eggshell composite and graphite worked well over a wide range of pH (Rao and Karthikeyan 2012;Na and Park 2010;Sakhare et al 2012;Thakre et al 2010;Lunge et al 2012;Karthikeyan and Elango 2008). Almost all the natural adsorbents studied such as SMP, chitin -cellulose composite, 20 % La-chitosan, Cynodan dactylon, Phylanthus embilica have optimum removal efficiency at neutral pH range (Asgari et al 2012;Jayapriya et al 2011;Kamble et al 2007;Alagumuthu et al 2010;Veeraputhiran and Alagumuthu 2011).…”

“…Kamble et al (2009) observed that addition of carbonate and bicarbonate ions resulted in increased pH of the fluoride solution which may be another reason for lowering of adsorption capacity. A few adsorbents such as manganese oxide coated alumina, lanthanum oxide and natural adsorbent bark of babool showed no effect in their respective adsorption capacities in presence of interfering anions (Maliyekkal et al 2006;Na and Park 2010;Mamilwar et al 2012) which is of great practical utility.…”

“…Batch studies indicate a removal of 90 % in 30 min from a 4 mg/L fluoride solution. Lanthanum hydroxide has also been used for defluoridation studies by Na and Park (2010). Langmuir isotherm model fitted the best and the sorption capacity was found to be 242.2 mg/g at pHeq B 7.5 and 24.8 mg/g at pHeq [ 10.0.…”