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Removal of humic acid from peat water using untreated powdered eggshell as a low cost adsorbent
Zulfikar, M. A.; Novita, E.; Hertadi, R. & Djajanti, S. D.
Abstract
The main objective of this study is to investigate the possibility of powdered eggshell used as an
adsorbent material for removal of humic acid from peat
water. The influences of contact time, dose of eggshells,
pH, and temperature were the factors considered in the
removal processes of humic acid from peat water. In
addition, adsorption isotherms of humic acid onto the
powdered eggshell were also evaluated with the Langmuir
and Freundlich approximations. Our results showed that
the equilibrium of the process was eventually established
after 60 min of the contact time, and also found that using
5 g of the powdered eggshell nearly 95 % of humic acid
has been successfully removed from the peat water. The
removal of humic acid gave better result when it was
conducted at low pH, and it was almost unaffected the
temperatures variation. The data was well fitted to Freundlich isotherm with the correlation coefficient of not <0.999, and could uptake the humic acid about 126.58 mg/g
at pH 4.01, estimated from the Langmuir model. The
kinetic experimental data proportionally correlated with the
pseudo-second-order kinetic model with a rate constant in
the range of 0.016-0.112 g mg
-1
min
-1
, while intra-particle-diffusion were the main rate determining step in the humic acid removal process. The powdered eggshell
investigated in this study, thus, exhibited as a high potential
adsorbent for the removal of humic acid from peat water.
Keywords
Adsorption; Calcium carbonate; Isotherm; Kinetics
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