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The design and synthesis of metalloid imprinted materials is a challenge due to lack of a feasible functional monomer. A novel cyclic functional monomer (CFM) was used to develop Sb(III)-ion imprinted polymer (CFM-IIP) for efficient and selective removal Sb(III). CFM possesses positively charged imidazolium moiety and specific cyclic size matching with Sb(III). CFM-IIP has a maximum Sb(III) adsorption capacity of 79.1 mg·g–1, while that of a noncyclic functional monomer imprinted polymer (NCFM-IIP) is only 30.9 mg Sb(III)·g–1. The relative selectivity coefficients of CFM-IIP compared to NCFM-IIP for Sb(III)/Cl–, Sb(III)/NO3–, Sb(III)/PO43–, Sb(III)/SO42–, and Sb(III)/Cr2O72– were 6.6, 78.4, 5.9, 3.0, and 3.2, respectively. Kinetic data fitted well with pseudo-second-order model. The adsorption between Sb(III) and CFM-IIP was identified to be feasible, spontaneous, and endothermic. ζ-Potential, X-ray photoelectron spectroscopic analysis, and density functional theory calculations revealed the mechanism of ...

Cadmium ion-imprinted polymers (Cd-IIP) were synthesized by precipitation polymerization using a complex of dithizone and cadmium as a template. The saturation adsorption capacity of the Cd-IIP is two times that of the nonimprinted polymers (Cd-NIP). Homogeneous binding sites are confirmed by the Langmuir isotherm. The adsorption kinetics fit a pseudo-second-order model well; and the adsorption equilibrium time is only approximately 20 min. The effect of coexisting ions on the Cd(II)-IIP and NIP were investigated by competing with Pb(II), Zn(II), Co(II), and Cu(II), and the ratio of relative selectivity coefficients was greater than 1.68. Thermodynamic parameters indicated that Cd(II) adsorption over IIP and NIP was a spontaneous and exothermic process. The enthalpy changes in different temperatures and adsorption energy are lower than −20.0 and 8 kJ/mol; respectively. These indicate that the adsorption process may be dominated by physisorption. The Cd-IIP was used for five cycles with a small decrease in...

Metal organic frameworks (MOFs) have been regarded as robust adsorbents for the adsorptive removal of organic pollutants because of their unique characteristics. However, the application of MOFs in the removal of metals from water is still rare. In this paper, amino-functionalization of Cr-based MOFs MIL-101 are modified through coordination bonding of unsaturated Cr metal centers with the -NH2 group in ethylenediamine (ED), and we demonstrate their excellent performance for the removal of Pb(II) ions from water. The Fourier transform infrared verifies that the ethylenediamine was grafted successfully on MIL-101. Furthermore, the results of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy show that the structure of ED-MIL-101 with an appropriate amount of ED almost does not collapse and retains the original performance of MIL-101. The adsorption capacity of ED-MIL-101, which is more than five times that of MIL-101, is 81.09 mg.g(-1) for Pb(II) ions from aqueous samples. The selectivity coefficients of ED-MIL-101 for Pb(II)/Cu(II), Pb(II)/Zn(II), Pb(II)/Co(II), and Pb(II)/Ni(II) are 6.92, 24.02, 15.69, and 14.53, respectively. The adsorption kinetics of Pb(II) ions shows that the process fits well with a pseudo-second-order model, and the adsorption equilibrium time is only about 30 min. Moreover, the practical application of ED-MIL-101 achieves almost 97.22% removal efficiency for Pb(II) ions. These results indicate that ED-MIL-101 has great potential in selectively removing Pb(II) ions from water environment.