Hi, I am currently writing my master thesis about fluoride removal with adsorption using different adsorbents. The problem is that the adsorbents I have used so far give very poor results, and almost do not remove any fluoride at all. Am I doing something wrong? How may I improve the results? What may be the reasons for the poor removal efficiency? Any shared thoughts on the matter is appreciated.
Details:
I have tested for Granulated Activated Carbon (GAC), Powdered Activated Carbon (PAC) and Activated Alumina(AA).
The experiment is batch operated with synthetic water composed of NaF and de-ionised water. Fluoride content is 10 mg/l and adsorbent dosage is ranged from 1-10 g/l. Agitation time on a mechanical shaker (250 rpm) is 2 hrs. GAC and PAC showed no valuable removal at all, while AA (which, according to literature, should show promising results) showed a bit higher removal efficiency(about 20%), but still not as high as expected.
Nina,
Fluoride is very water soluble and a strong anion in water. It does not sorb to activated carbon. Thus, your experimental results are correct. Drinking water industry is in need of a good and economical sorbent for fluoride. You may want to review this recent paper that investigates polymer/alumina sorbents. Fluoride Removal from Aqueous Solutions Using Poly(Styrene Sulfonate)/Nanoalumina Multilayer Thin Films Thanjavur Chandrasekaran Prathna* and Ashok M. RaichurDOI: 10.1002/gch2.201700064
The basic problem with the literature information is that not always important details of the experiment are disclosed. It suffices not to mention the additional surface modification and the results cannot be repeated. Ask the authors for details.
Hi Nina!
As far as I know, an effective fluoride sorbent is activated titanium dioxide TiO2.
I would also suggest sorbing fluoride on basic aluminum sulfate AlOHSO4.
I hope this helps you.
hi
is it possible that only some ppm level fluoride sorbent is activated by given methods you need to atjust the consentration of some suitable alums qty