The Cu
2+ containing in the FeCl
3 solution is the worst matter to fatigue the solution and make trouble at the etching.
We determined the density of Cu
2+ by means of the complexon titration at pH 8; as a buffer solution-1N NH
4OH:NH
4Cl, as an indicator-MX (Murexide), as a Standard solution-M/100 EDTA.
To determine only Cu
2+ in the conjugated solution of Fe
3+:Fe
2+:Cu
2+ is not easy, and we tried the following procedures to separate the Cu
2+ from the solution.
I As seen Table 1 and 2 the results were brought out of the precipitation of Fe(OH)
3 with 1N CH
3COOH/1N CH
3COONa and titration of the separated Cu
2+.
II Table 3 and 4 are from the results of ether-extraction of Fe
3+ from the hydrochloric acidified sample for the determining Cu
2+. And Fig. 1 and 2 are showing the Cu
2+ to be absorbed at Fe(OH)
3 precipitation in I and II ways, they are according to Freundlich's formula of absorption.
III (1) Table 5, 6 and Fig. 3, 4 are showing the Cu
2+ taken out by utlizing a strong basic ion-exchangable resin; after producing the basic complexon, it is absorbed to the resin and separated Cu
2+ in difference of HCl acid concentration.
III (2) Table 7 and 8 are also showing the Cu
2+ from using the resin: after producing the Fe-EDTA complexon, it is absorbed to the resin for separating Cu
2+.
In the long run, on the numerical determination of Cu
2+ quantity I is the most simple way among them but apt to be making error, while the others II and III are doing good measurement but a little complicated ways.
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