The defluoridation of ground water is regarded as
one of the key areas of attention among the universal water
community. The present investigation deals with fluoride
removal from aqueous solution by thermally activated biosorbents
prepared from banana (
Musa paradisiaca
) peel and
coffee (
Coffea arabica
) husk. Fluoride ion selective electrode
was used for the determination andmonitoring of fluoride ion
concentration. Batch experiments were conducted to establish
the optimal conditions like pH, dose of the adsorbent, and
contact time. The optimum pH was found to be 2 for both the
adsorbents, and the optimum dose was found to be 24 g/
250 mL at 13 h contact time for banana peel and 18 g/250 mL
at 3 h contact time for coffee husk. The concentrations
determined in real water samples of flour factory, poultry, and
Lake Hawassa sites were 12.54, 11.02, and 6.72 mg/L,
respectively. The prepared biosorbents were applied on these
water samples under optimized conditions and found to be
effective with removal efficiency ranging from 80 to 84 %. In
terms of time and adsorbent dose required, coffee husk was
observed to be much better than banana peel. The adsorption
process obeyed Langmuir adsorption model. From the kinetic
perspective, the fluoride adsorption followed the pseudo second-
order reaction kinetics.
