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.com
Volume 7
Biosensors Journal
ISSN: 2090-4967
Electrochemistry 2018
June 11-12, 2018
June 11-12, 2018 | Rome, Italy
4
th
International Conference on
Electrochemistry
Calcareous electrochemical precipitation, a new method to trap dissolved metallic contaminants in
seawater
Peggy Gunkel Grillon
1
, Charlotte Carré
1
, Arnaud Serres
1
, Thomas Quiniou
1
, Marc Jeannin
2
and
René Sabot
2
1
University of New Caledonia, New Caledonia
2
University of la Rochelle, France
T
he contamination of coastal waters by trace metals is an important worldwide concern since they may significantly affect
marine ecosystems. A novel use of the calcareous deposit formed on a metallic structure is proposed to trap metallic
contaminants in seawater. It is the same deposit that builds up in many tea kettles or water pipes in areas where calcium-rich
water is the norm. Whereas the calcareous deposition is a common problem for many people, we transformed this problem
into a solution to trap metals. The calcareous deposit is formed in seawater by imposing a current on a galvanized steel
electrode. The working electrode’s potential reaches potential in the water reduction range. This reaction causes pH increase
at the seawater/metal interface, inducing calcium and magnesium precipitation. A voluminous calcareous deposit composed
of CaCO
3
and Mg(OH)
2
grows with polarization time. Experiments conducted
in situ
revealed that many metals can also be
trapped. In order to better control and understand the mechanisms, lab-experiments were performed in artificial seawater. We
first decided to study nickel trapping since nickel mining activities in New Caledonia are causing the subsequent pollution of
local coastal waters. Artificial seawater was doped with NiCl
2(s)
and analysis revealed that Ni is trapped mainly as β-Ni(OH)
2
.
Ni content increases with the initial Ni concentration in the electrolyte. Up to 24% in weight of Ni is trapped in the deposit
after seven days of polarization. The calcareous deposit appears like a simple implementation with just a metallic structure
immerged in seawater and connected to an electrical circuit which can be charged by renewable energy. This electrochemical
method is thus a promising and cheap clean-up device for remediation of contaminated seawater.
Recent Publications:
1. Carre´ C, Gunkel Grillon P, Serres A, Jeannin M, Sabot R and Quiniou T (2017) Calcareous electrochemical
precipitation, a new method to trap nickel in seawater. Environmental Chemistry Letters 15(1):151-156.
2. Pasquet C, Le Monier P, Monna F, Durlet C, Brigaud B, Losno R, Chateau C, Laporte Magoni C and Gunkel Grillon
P (2016) Impact of nickel mining in New Caledonia assessed by compositional data analysis of lichens. SpringerPlus
5(1):2022.
3. Pasquet C, Gunkel Grillon P, Laporte Magoni C, Serres A, Quiniou T, Rocca F, Monna F, Losno R, van Oort F and
Chateau C (2016) Alternative dry separation of PM10 from soils for characterization by kinetic extraction: example of
New Caledonian mining soils. Environmental Science and Pollution Research 23(24):25105-25113.
4. Gunkel Grillon P, Roth E, Laporte Magoni C and Le Mestre M (2015) Effects of long term raw pig slurry inputs on
nutrient and metal contamination of tropical volcanogenic soils, Uvéa Island (South Pacific). Science of the Total
Environment 533:339-346.
5. Gunkel Grillon P, Laporte Magoni C, Lemestre M and Bazire N (2014) Toxic chromium release from nickel mining
sediments in surface waters, New Caledonia. Environmental Chemistry Letters 12(4):511-516.
Peggy Gunkel Grillon et al., Biosens J 2018, Volume 7
DOI: 10.4172/2090-4967-C1-002