Effect of formaldehyde on Cu(II) removal from synthetic complexed solutions by ion exchange.

Ruey-Shin Juang, Su-Hsia Lin, Hsiang-Chien Kao, Ming-Huei Theng

Department of Chemical Engineering and Materials Science, Yuan Ze University, Chung-Li 320, Taiwan. rsjuang@ce.yzu.edu.tw

Chemosphere 2005 Jun

filter terms:

The effect of formaldehyde (HCHO) on the ion exchange of Cu(II) from an equimolar EDTA (ethylenediaminetetraacetic acid, H(4)L) solution with a strong-base Amberlite IRA-400 resin was studied. Experiments were conducted as a function of the initial concentration of Cu(II) (0.5-10 mM), solution pH (1.0-6.0), HCHO concentration (0-6 vol%), and temperature (15-35 degrees C). It was shown that the amount of exchange of Cu(II), which exists in the form of complexed anions CuL(2-), increased with increasing solution pH and reached a plateau at an equilibrium pH (pH(e)) of 3.5. However, the amount of exchange decreased with increasing HCHO concentration up to 3 vol% but then slightly decreased with a further increase in HCHO concentration. Such effect of added HCHO was determined by the following two factors: the competitive exchange of HCOO(-) anions and the enhanced exchange of Cu(I) in the form of complexed anions CuL(3-). The exchange isotherm obtained at a fixed pH(e) could be well described by the Langmuir equation. The isosteric enthalpy change for the present ion exchange process was also evaluated and discussed.

Citation

Ruey-Shin Juang, Su-Hsia Lin, Hsiang-Chien Kao, Ming-Huei Theng. Effect of formaldehyde on Cu(II) removal from synthetic complexed solutions by ion exchange. Chemosphere. 2005 Jun;59(9):1355-60