Journal of Advances in Technology and Engineering Studies JATER
2017, 3(5): 170-175
PRIMARY RESEARCH
Inluence of pyrogallol on the catalytic effects of Fe
3+
during Fe
2+
oxidation with
atmospheric oxygen
S. O. Celik
1
, S. Günes Durak
2*
, T. Ormanci Acar
3
, G. Türkoglu Demirkol
4
, Ö. Mutlu Salmanli
5
,
N. Tüfekci
6
1
Corlu Faculty of Engineering, Namik Kemal University, Tekirdağ , Turkey
2
Faculty of Engineering-Architecture, Nevsehir Hacı Bektas Veli University, Nevsehir, Turkey
3, 4, 6
Faculty of Engineering, Istanbul University, Istanbul, Turkey
5
Faculty of Civil Engineering, Istanbul Technical University, Maslak, Istanbul, Turkey
Index Terms
Pyrogallol
Catalytic Effect
Ferric Hydroxide
Ferrous Iron
Oxidation
Atmospheric Oxygen
Received: 26 July 2017
Accepted: 4 September 2017
Published: 9 October 2017
Abstract — One of the most common methods for the removal of iron from water is oxidation of the fer-
rous iron to the ferric form by atmospheric oxygen. Ferric hydroxide yielding from hydrolysis of ferric iron
precipitates which is settled and iltered out from the water. The oxidation rate of the ferrous iron is affected
by several factors such as the concentrations of Fe
2+
, Fe
3+
, and oxygen, pH, temperature, organic matter,
and other ions present in the solution. Considerable concentrations of dissolved iron can be preserved in
aerobic aquatic systems in the presence of organic species of natural origin. Organic species such as tannic
acid, gallic acid, and others can completely retard the oxidation of Fe
2+
for several days, even under an
oxygen partial pressure of 0.21 atm. In this study, the effect of Fe3+ on Fe
2+
oxidation in water containing
pyrogallol was simulated and investigated experimentally in two stages. In the irst stage, catalytic effect of
Fe
3+
on Fe
2+
oxidation has been investigated, experimentally. In the second stage, it has been studied how
pyrogallol affects the oxidation of Fe
2+
and the catalytic effect of Fe
3+
. Without pyrogallol, the oxidation
rate of Fe
2+
was enhanced by increasing Fe
3+
concentration. The catalytic effect of Fe
3+
clearly decreased
and almost vanished in the presence of pyrogallol. This is considered to be a result of pyrogallol-forming
complexes with Fe
3+
.
© 2017 The Author(s). Published by TAF Publishing.
I. INTRODUCTION
Ground waters in Turkey generally contain Fe
2+
above the allowed limits for consuming as drinking water.
For this reason, it is necessary to remove Fe
2+
from water.
Redox reactions affect the chemical forms of iron in natural
waters via photoreduction, thermal reduction of Fe
3+
or
oxidation of Fe
2+
.
Different kinds of organic matters can be present in
water along with Fe
2+
. These Fe
2+
oxidation products can
be consumed by the other constituents such as Natural Or-
ganic Matters (NOM) [1]. NOM in natural waters usually
quicken the oxidation reaction at typical ambient pH, which
has been attributed to many humic substances that have
the high density of carboxylate binding sites [2]. Lee et al.
[1] conducted a study with Sagami River water samples to
investigate the effect of NOM on Fe
2+
oxidation. They deter-
mined the oxidation rate was accelerated up to 3.4-fold with
the existence of humic-type NOM. Whereas bioavailability
of iron decreases in the presence of humic-type NOM. Be-
sides, some humic acid constituents can form complex with
ferrous iron and retard the oxidation [3].
*
Corresponding author: S. Günes Durak
†
Email: ssevgigunes@gmail.com
© The Author(s). Published by TAF Publishing. This is an Open Access article distributed under a Creative Commons
Attribution-NonCommercialNoDerivatives 4.0 International License