Synthesis of ion-imprinted mesoporous silica gel sorbent for selective adsorption of copper ions in aqueous media

Five Cd(II) Complexes Decorated with Pyridine-2,6-dicarboxamide and Salicylaldimine Units Showing Selective Recognition and Removal of Cu(II) Ions

A racemic ligand (LP/LM) incorporating pyridine-2,6-dicarboxamide and salicylaldimine units was synthesized by extending our previous work. Five Cd(II) complexes [Cd2L2I4]·2DMF (1), [Cd2L2Br4]·2DMF (2), {[CdLCl2]·MeOH·H2O}n (3), {[Cd2L2(NO3)4(DMF)(MeCN)]·2H2O}n (4), and {[CdL2(H2O)2]·2ClO4·2H2O·2MeOH}n (5), were synthesized by combining this ligand with the respective CdX2 salts (X = I-, Br-, Cl-, NO3-, and ClO4-). The structural diversity of these complexes revealed the chiral self-discrimination or self-recognition process of racemic ligand L in coordinating to Cd(II) salts. Furthermore, the selective ion recognition of these complexes was examined by UV-vis spectra. The results showed that all the Cd(II) complexes displayed selective ion recognition of Cu2+ in DMF due to the formation of polynuclear Cd(II)-Cu(II) complexes. Experiments on the removal of Cu2+ by the Cd(II) complexes were carried out in aqueous solution, which showed the complexes selectively removed Cu2+ from aqueous solutions containing various metal ions.

Green multi-functional monomer based ion imprinted polymers for selective removal of copper ions from aqueous solution

Green ion imprinted polymers (IIPs) were prepared in aqueous phase via the synergy of three functional monomers of low-cost eco-friendly gelatin (G), 8-hydroxyquinoline (HQ) and chitosan (C), namely G-HQ-C IIPs, and were applied as an effective and recyclable adsorbent to remove Cu(II) from aqueous solution. The as-prepared G-HQ-C IIPs were systematically characterized, and several major factors affecting adsorption capacity including solution pH, temperature and contact time were investigated in detail. The adsorption of Cu(II) on G-HQ-C IIPs followed the pseudo-second-order kinetic and Langmuir isotherm models, and the adsorption capacity increased with temperature increase. Moreover, the maximum adsorption capacities of G-HQ-C IIPs toward Cu(II) reached up to 111.81 mg/g at room temperature, much higher than those of most of the reported adsorbents for Cu(II). The G-HQ-C IIPs displayed excellent selectivity against seven common divalent ions with selectivity coefficients above 18.71, as well as high anti-interference ability. Additionally, a good reusability was demonstrated without significant loss in adsorption capacity after at least ten cycles. The IIPs were applied to environmental water samples for selective removal of Cu(II) with satisfactory results. By replacing Cu(II) template by Cd(II), Hg(II) and Pb(II), respectively, the obtained three kinds of IIPs based on G-HQ-C presented convincing imprinting properties, and therefore the work could provide a simple and general imprinting strategy toward various concerned heavy metal ions through multi-point interactions from multiple functional monomers.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.