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Indian Journal of Chemical Technology (IJCT) >
IJCT Vol.17 [2010] >
IJCT Vol.17(2) [March 2010] >
| Title: | Fluoride removal from water using crushed limestone |
| Authors: | Nath, Suresh K
Dutta, Robin K |
| Keywords: | Defluoridaton
Limestone
Calcite
Acetic acid
Citric acid |
| Issue Date: | Mar-2010 |
| Publisher: | CSIR |
| Abstract: | An examination of defluoridation by
industrial grade limestone indicated that a combination of precipitation and
adsorption of fluoride can be more effective for defluoridation of water.
Pre-acidified fluoride water using two edible acids, viz., acetic acid (AA) and citric acid (CA) have been used for
treatment by crushed limestone of diameter 3-4 mm to precipitate fluoride as
CaF2 in addition to adsorption of fluoride on limestone. The study
has been carried out in batches by varying the acid concentration and contact
time. Addition of the acids to the water before treatment with the crushed
limestone in batch tests significantly improved the fluoride removal and this
increased with the increase in the concentrations of the acids. The
concentration of CA and AA required bringing down the fluoride concentration
from 10 to 1.5 mg/L, are 0.05 M and 0.033 M, respectively, when the crushed
limestone chips sample was used for the first time with contact time of 12 h. The
acids are neutralized by limestone during the defluoridation process and the
resulting final pH of the treated
water was found to be in the ranges of 6.2 and 7.0 for CA and 5.7 and 7.0 for
AA. |
| Page(s): | 120-125 |
| ISSN: | 0975-0991 (Online); 0971-457X (Print) |
| Source: | IJCT Vol.17(2) [March 2010]
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