The extraction and separation of Copper(II) from its aqueous solutions, by using swelled crown ether (PDB18C6)

Abstract

This study included the extraction and separation of Copper(II) from its aqueous
solutions, by using swelled crown ether (PDB18C6), and included the following:
It was found that; the copper(II) is extracted when (pH=10), percentage extraction
reached (E%=93.5).but Its extraction was impossible from the acidic media (HCl ,
H2SO4 , HNO3). The results also showed that the alkaline media was suitable for the
extraction of copper(II), and the high percentage value for it’s equal to (E%=98) was
obtained at [0.01M] from KOH. It was found from experiments that the best shaking
time was (60) minutes. Adding ethanol to aqueous phase (40%V/V)
at (20 1Co ) m temperature gave the best extraction percentage for copper (II)
(E%=64.2).
Percentage extraction of copper(II) from the salt media (KCl, NaCl) were low in
comparison with the alkaline media. The selectivity of saturated solid polymer
towards the extraction of copper(II) ions, in the present of the positive ion
(Li+ ,Na+ ,K+ ,Rb+ ,Ba+2 ,Sr+2 ,Ca +2 ,Cd+2 ,Ni+2 ,Mg+2 ) and the negative ions
(F− ,Br− ,Cl− ,I− ) , was also studied.
The effect of temperature and thermodynamics functions on the process of
extraction of copper(II) ions was studied, and it appeared that the extraction enthalpy
ΔHex ,has a negative value in the case of copper, which means that the extraction
process is exothermic and the free energy for extraction ΔGex showed negative value
and the extraction entropy ΔSex showed positive value at all temperatures. Which
means that the reaction is instantaneous.
The separation of copper from palladium ions was done on a chromatographic
column filled with the substance (PDB18C6), which is treated previously with (2.0M)
KOH solution, and by using the same solution as a mobile phase to elute Pd (II) first.
The process was done on eight batchs, and in each batch (10ml) was used from the
mobile phase, while in the case of other eluted back the copper from column, (1.0M)
of HCl was used for five batchs, and in each batch (10ml) was used, and the speed of
flow-rate for both ions was 1ml/min.