dc.description.abstract |
Permanent consumption of higher concentrations causes both dental fluorosis and skeletal
fluorosis. The WHO guideline value for fluoride in drinking water is 1.5 mg/l. High fluoride
concentrations are particularly critical in developing countries, largely because of lack of
suitable infrastructure for treatment (Feenstra et al., 2007). Thus, the development of cost-effective, locally available, and environmentally respectful adsorbents for fluoride removal
from contaminated water sources is absolutely required. This study was developing surface
modified wood charcoal by aluminum hydroxide.
Characterization of the raw and modified adsorbent was carried out using proximate
analysis, FTIR, and XRD. Surface modification of charcoal was accomplished by an
Aluminum hydroxide functionalization process, using Al2 (SO4)3.18H2O as the aluminum
bearing solution. The experimental study was designed to use a full factorial approach with a
3
3
which were the three factors with the three levels and with runs in duplicate by State Ease
Design Expert 13 software. The batch adsorption method was used to experimental
defluoridation of water. The effects of various parameters affecting fluoride removal
efficiency, such as adsorbent dose, contact time, and initial fluoride concentration were
studied.
The moisture content, ash content, volatility, fixed carbon and bulk density of the modified
adsorbent were 5.24%, 3.5%, 18%, 72.1%, and 0.432 g/ml respectively. Those
characteristics of material indicate the possibility of materials for adsorption. The maximum
fluoride removal efficiency (88.5%) was obtained at adsorbent dose 1.5gm, contact time 120
min, and initial fluoride concentration of 15mg/L. The amount of fluoride removal increased
as the initial concentration of fluoride decreased and also increased as the contact time and
amount of adsorbent increased at neutral pH of the solution. The adsorption data were well
fitted to Langmuir isotherm (R
2
=0.9905) model with a maximum adsorption capacity of 15
mg/g compared to Freundlich isotherm (R
2
= 0.9887) to describe the adsorption
characteristics of fluoride on aluminum hydroxide modified charcoal. The adsorption
kinetics was fitted in a pseudo second order rate equation with R
2
=0.98.
Keywords: charcoal; defluoridation; aluminum hydroxide; adsorption isotherm, and kinetics |
en_US |