XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3113
Linear Sweep Voltammetry (LSV)
LSV was used to study the electrochemical interaction
between ligands and the Cu electrode, where the applied
potential was ramped from the open circuit potential up by
+1.0 V. First, two measurements in borate buffer without
ligands added were conducted (Figure 7), one with moderate
stirring (solid blue line) and one without stirring (dashed-
dotted blue line). As the applied potential increased, the
resultant anodic current exhibited an initial slow rise with
a progressively accelerated rate of increase, adhering to
an exponential growth pattern. Subsequently, the rate of
increase in current declined before experiencing another
period of growth. The applied potential window covered
the oxidation of Cu to Cu2O and further CuO. OCP val-
ues suggest that the Cu electrode surface had already been
oxidized. When the applied potential ramped up from
OCP to a low potential range, e.g., +0.10 to +0.15 V, the
impact of stirring was negligible, and the charge transfer
rate of Cu oxidation was slow, reaction kinetics limited.
Continuously increasing the applied potential, higher
anodic currents appeared when stirring was employed. This
divergence occurred because stirring facilitated the trans-
port of OH– to the electrode surface and the dissolution
of atmospheric O2, resulting in more intensive interaction
and increased current.
LSV experiments were performed at various concen-
trations of AIBTC using two different sweep rates (10 and
50 mV/s, Figure 7). The solution kept being stirred mod-
erately during measurements. In the potential range near
the OCP, the current measured followed a nearly exponen-
tial increase and exhibited a trend resembling Tafel kinetics
at slightly higher potentials. The current-potential curves
within the low potential range displayed greater conver-
gence and less dependence on whether it was stirred, ligand
concentration, and sweep rate. This suggests that the anodic
current generated by scanning up the potential was less
affected by the transport phenomenon but dominated by
the reaction kinetics. Beyond the early potential range, as
the potential raised further, the currents diverged from each
other under various scenarios, indicating a more significant
impact of mass transfer. The faster the sweep rate was, the
steeper the current curves against the applied potential
since the current represents the flow of electric charge per
unit of time.
Analysis was performed at 50 mV/s (Figure 8(a)).
Above the OCP of the 0M AIBTC solution, introducing
AIBTC first reduced the current at the same applied poten-
tial compared to the current measured in the borate buffer
alone. This reduction implies that the adsorption of AIBTC
passivated the Cu electrode surface, and thus, the oxidation
of Cu was inhibited. In this passivation range, no promi-
nent peak was observed. Therefore, it’s more likely that
the chemisorption of AIBTC on the Cu electrode surface
occurred instead of AIBTC being engaged in a redox reac-
tion with Cu to form a bulk Cu-AIBTC complex. The che-
misorption mechanism is analogous to the electrochemical
adsorption of xanthate on the Cu electrode, as proposed by
Woods (1971), and shows similarity to the adsorption of
IPETC on the Cu electrode, as studied by Basilio (1989).
As potential surpassed a certain threshold, the current
in the presence of AIBTC exceeded that when no AIBTC
was added. The increase in the anodic current indicates
additional oxidizing reaction(s) happening on the Cu elec-
trode. The activation of the Cu electrode surface might
Figure 7. Linear sweep voltammograms w/o stirring and at various
concentrations of AIBTC using sweep rates of 10 and 50 mV/s
Linear Sweep Voltammetry (LSV)
LSV was used to study the electrochemical interaction
between ligands and the Cu electrode, where the applied
potential was ramped from the open circuit potential up by
+1.0 V. First, two measurements in borate buffer without
ligands added were conducted (Figure 7), one with moderate
stirring (solid blue line) and one without stirring (dashed-
dotted blue line). As the applied potential increased, the
resultant anodic current exhibited an initial slow rise with
a progressively accelerated rate of increase, adhering to
an exponential growth pattern. Subsequently, the rate of
increase in current declined before experiencing another
period of growth. The applied potential window covered
the oxidation of Cu to Cu2O and further CuO. OCP val-
ues suggest that the Cu electrode surface had already been
oxidized. When the applied potential ramped up from
OCP to a low potential range, e.g., +0.10 to +0.15 V, the
impact of stirring was negligible, and the charge transfer
rate of Cu oxidation was slow, reaction kinetics limited.
Continuously increasing the applied potential, higher
anodic currents appeared when stirring was employed. This
divergence occurred because stirring facilitated the trans-
port of OH– to the electrode surface and the dissolution
of atmospheric O2, resulting in more intensive interaction
and increased current.
LSV experiments were performed at various concen-
trations of AIBTC using two different sweep rates (10 and
50 mV/s, Figure 7). The solution kept being stirred mod-
erately during measurements. In the potential range near
the OCP, the current measured followed a nearly exponen-
tial increase and exhibited a trend resembling Tafel kinetics
at slightly higher potentials. The current-potential curves
within the low potential range displayed greater conver-
gence and less dependence on whether it was stirred, ligand
concentration, and sweep rate. This suggests that the anodic
current generated by scanning up the potential was less
affected by the transport phenomenon but dominated by
the reaction kinetics. Beyond the early potential range, as
the potential raised further, the currents diverged from each
other under various scenarios, indicating a more significant
impact of mass transfer. The faster the sweep rate was, the
steeper the current curves against the applied potential
since the current represents the flow of electric charge per
unit of time.
Analysis was performed at 50 mV/s (Figure 8(a)).
Above the OCP of the 0M AIBTC solution, introducing
AIBTC first reduced the current at the same applied poten-
tial compared to the current measured in the borate buffer
alone. This reduction implies that the adsorption of AIBTC
passivated the Cu electrode surface, and thus, the oxidation
of Cu was inhibited. In this passivation range, no promi-
nent peak was observed. Therefore, it’s more likely that
the chemisorption of AIBTC on the Cu electrode surface
occurred instead of AIBTC being engaged in a redox reac-
tion with Cu to form a bulk Cu-AIBTC complex. The che-
misorption mechanism is analogous to the electrochemical
adsorption of xanthate on the Cu electrode, as proposed by
Woods (1971), and shows similarity to the adsorption of
IPETC on the Cu electrode, as studied by Basilio (1989).
As potential surpassed a certain threshold, the current
in the presence of AIBTC exceeded that when no AIBTC
was added. The increase in the anodic current indicates
additional oxidizing reaction(s) happening on the Cu elec-
trode. The activation of the Cu electrode surface might
Figure 7. Linear sweep voltammograms w/o stirring and at various
concentrations of AIBTC using sweep rates of 10 and 50 mV/s