4th EucheMs chemistry congress

wednesday, 29-Aug 2012
s651
chem. Listy 106, s587–s1425 (2012)
Environment and Green Chemistry
Environmental Chemistry – Metals, transformation
o - 2 8 4
tASK SPeCifiC ioniC LiquidS SyntheSiS:
APPLiCAtion to MetAL ionS extrACtion
A. MeSSAdi 1 , S. BoudeSoCque 1 , L. duPont 1 ,
A. MohAMAdou 1
1 Institut de chimie Moléculaire de Reims, Groupe GCC, Reims,
France
Our work aims to design cationic organic chelating synthons
derived from vegetal or animal renewable resources (betaine,
glycine or alanine), which can generate original task specific ionic
liquids by association with an inorganic anion. These ionic liquids
(ILs) are used in order to develop process for pollution
remediation.
The cationic synthons, obtained in the form of bromide salts,
can generate ionic liquids by metathesis reactions in the presence
- - - of the desired anionic salt [BF , PF6 , NO3 , (NC)2N 4
- - (Dca), ClO4 and (CF SO ) N- (NTf )]. A series of ionic liquids (ILs) are
3 2 2 2
isolated and characterized by various physicochemical methods
(elemental analysis, 1H and 13C NMR, IR, DSC, viscosity,
Karl Fischer titration, crystal XRD).
The extraction of the different metal cations (Cu2+ , Ni2+ and
Pb2+ ) in aqueous solution by ionic liquids synthesized was
performed. The extraction yields, determined by the
measurements of the residual metal concentration in aqueous
solution, depend not only the length of the alkyl chain appending
to the ammonium nitrogen but also on the nature of the associated
anion. The most promising results are obtained with ILs whose
anion has a chelating ability. The mechanism of metal transfer has
been studied and was related to the hydrophobicity of the cationic
synthon. Increasing the hydrophobicity of the cationic synthon
leads to an increase of extraction yield, thus limiting ion-exchange
(transfer of the cation of LI in the aqueous phase) and promoting
ion pairing extraction.
Keywords: Ionic liquids; Ion pairs; Amino acids; Ion
exchange; Transition metals;
4 th EucheMs chemistry congress
Environmental Chemistry – Metals, transformation
o - 2 8 5
CorK APPLiCAtion for CLeAninG MetAL
ContAMinAted wAterS
C. B. LoPeS 1 , i. noGueirA 1 , r. neveS 1 ,
d. S. tAvAreS 1 , A. C. duArte 1 , e. PereirA 1
1 University of Aveiro, Department of Chemistry, Aveiro,
Portugal
Metals have become of utmost importance due to our
planet’s increasing populations and their requirements for natural
resources and metals-based goods. The continuous demand for
metals has originated metal rich wastewaters and metal
contamination problems all over the world. Today, metal
contamination has accomplished high visibility and is garnering
public concern, since population is less and less tolerant of any
risks to their health, safety and quality of life. The impacts that
metal contamination has on both public health and ecosystems
have forced the regulatory entities to the drive for strict
environmental standards and reduction in metal releases and
discharges. All over the world, industries are forced to reduce the
metal contents in industrial waters to limit levels. Activated
carbon is one of the most used sorbent to remove metals from
waters, but due to its expensive cost, waste based sorbents have
been emerging as a low cost alternative.
Cork stoppers are an abundant waste from households and
restaurant units. They are composed mostly by natural cork, and
its main polymeric components are suberin, lignin and
polysaccharides. Their chemical groups are the main responsible
for their capacity to uptake metals. In this study the efficiency of
this biomass to uptake Hg, Cd and Pb from different types of
water have been studied in batch stirred vessels at room
temperature.
Cork have shown higher appetence to remove Hg(II) and
Pb(II), achieving removal percentages as higher as 95%.The
sorption process was studied under the effects of competing ions
and organic matter content, and it is well described by well-known
kinetics models. This study suggests that this waste based sorbent
may be effectively used to reduce metal content in low and
moderate contaminated waters.
Acknowledgements: Cláudia B. Lopes thanks Fundacio para
a Ciencia e Tecnologia-FCT, for financial support through a
Post-Doctoral grant SFRH/BPD/45156/2008
Keywords: Metals; Cork; Sorption; Competing ions; Organic
matter;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc