Dual use of colorimetric sensor and selective copper removal from aqueous media with novel p(HEMA-co-TACYC) hydrogels: Cyclen derivative as both monomer and crosslinker.

Within the scope of this study, p(2-hydroxyethyl methacrylate-co-tetraacrylic cyclen) (p(HEMA-co-TACYC)) hydrogels were synthesized for the first time in the literature using a tetraacrylic cyclen (TACYC) as both functional monomer and crosslinker. The hydrogels designed especially for Cu ions showed colorimetric sensor behavior selective for Cu ions in all aqueous media (deionized, tap, river and sea water) and in metal ion mixtures. The p(HEMA-co-TACYC) hydrogels forming a stable complex with Cu ions simultaneously showed properties of being a good adsorbent material. The hydrogels have reuse capacity as both sensor and adsorbent material. Changing the amount of TACYC in the hydrogel structure changes the maximum adsorption capacity for Cu ions. The Langmuir and Freundlich adsorption constants for Cu ion adsorption of the hydrogels, acting as selective adsorbent in all aqueous media and metal ion mixtures, were determined.