Solution conductivity and type of power supply
Conductivity of the solution is very important parameter
in electrolysis process as the removal efficiency of the
pollutant and operating cost are directly related to the
solution conductivity [45]. The conductivity of an electrolyte
solution is a key property. In an electrochemical
process, the conductivity determines the cell resistance
while the properties of solvent and electrolyte determine
their interaction with the electrically active species and
thereby influence the electrode reactions [47].
The solution must have some minimum conductivity
for the flow of the electric current. The conductivity of
the low-conductivity wastewater is adjusted by adding
sufficient amount of salts such as sodium chloride or sodium
sulphate. There is an increase in the current density
with an increase in the conductivity of the solution at
constant cell voltage or reduction in the cell voltage at
constant current density [48]. The energy consumption
is decreased with high performance/approach solution.
The energy consumption is decreased with high conductivity
solution. In the EC process, there is an in situ
generation of metal hydroxide ions by electrolytic oxidation
of the sacrificial anode. These metal hydroxide ions
act as coagulant and remove the pollutants from the solution
by sedimentation. Majority of the studies reported
in the literature have used direct current (DC) in the EC
process. The use of DC leads to the corrosion formation
on the anode due to oxidation. An oxidation layer also
form on the cathode reducing the flow of current between
the cathode and the anode and thereby lowering
the pollutant removal efficiency [49]. These limitations
of the DC electrocoagulation process have been decreased
to some extent by the addition of parallel plate sacrificial
electrodes in the cell configuration.