Abstract:
In this study, the main objective is to develop a good chelation and ion exchange hydrogel. This
hydrogel is obtained by polymerization of dimethyl amino ethyl methacrylate (DMAEMA) and
acrylic acid (AAc) by gamma irradiation, for the purpose of separation of some heavy and toxic
metals from water. UV spectroscopy is applied to determine the metal ion concentration before
and after treatment. The FTIR spectral analysis has identified the bond structure of PAAc,
DMAEMA and P (DMAEMA/AAc) hydrogels. Microstructure and nanostructure are investigated by
means of SEM and positron annihilation lifetime spectroscopy (PALS) respectively. A maximum
swelling percent is found for 80/20 DMAEMA/AAc at free-volume hole size and fraction of 97 Ǻ3
and 3.4% respectively. The P (DMAEMA/AAc) and PAAc hydrogels have been applied for Cu+2, Co+2
and Ni+2 removals from aqueous solutions, and the factors affecting the adsorption capacity are
determined. The adsorption capacity of P (DMAEMA/AAc) is found to be higher than the corresponding
ones PAAc. Its experimental results showed that, the maximum adsorption of P
(DMAEMA/AAc) after 24 h occurs at pH 7 with concentration of 250 ppm for Ni+2 ions and at pH 5
with concentration of 40 ppm for Cu+2 and Co+2 ions. The adsorption affinity of P (DMAEMA/AAc)
hydrogel at different treatment contact times is in the following order Ni > Cu > Co. However, the
order becomes Co > Ni > Cu by the variation of the pH of the metal ion solution; the variation of its
concentration leads to a different order of Cu > Co > Ni.
