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In this study, the functional monomers, N-methacryloyl-L-aspartic acid and N-methacryloyl-L-cysteine were synthesized through a reaction between appropriate amino acids and methacryloyl chloride. Then, Pb(II) or Cd(II) ion-imprinted 2-hydroxyethyl methacrylate based cryogels were prepared by free radical polymerization method under partially frozen conditions. Following the characterization of matrices, adsorption of heavy metal ions was examined in batch mode from aqueous solution considering several parameters affecting the adsorption performance. The actual adsorption capacities were 44.5, 65.3, and 86.7 mg/g for Cd-1, Cd-2, and Cd-3 cryogels meanwhile those were 41.9, 86.3, and 122.7 mg/g for Pb-1, Pb-2, and Pb-3 cryogels, respectively at optimum pH: 5.5. By increasing temperature, adsorption capabilities of both cryogels were inhibited because of the electrostatic nature of coordinated covalent bonds and collapsing of coordination spheres. The adsorption process was very fast, the equilibrium adsorption was achieved in about 60 min, which was directly related to macroporous structure and interconnected flow-channels of cryogels. Kinetics and adsorption isotherms were also studied. Langmuir isotherms and pseudo-second order kinetic model were well suited to adsorption data, which also indicated that the process occurred without any diffusion restrictions or steric hindrances. Finally, the competitive adsorption studies were performed using multi-ion containing synthetic wastewater to show whether the cryogels developed are suitable for specific heavy metal recycling or not.

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In this study, the molecularly imprinted polymers (MIPs) that will be formed by the sulfamethoxazole (SMX) molecule and methacrylic acid (MAA) molecule were examined theoretically. The most stable interaction region between the two molecules was determined in solvent environments (ethanol, acetonitrile, and dimethylsulfoxide), and monomer ratios (SMX/MAA; 1:1, 1:2, and 1:3) were examined to form the most stable geometry. The number and length of the hydrogen bonds formed between the template molecule and the functional monomer and the interaction between the atoms were determined. Geometry optimizations of the molecules were calculated by the DFT method at the M06-2X/ccpVTZ level, and single-point energy calculations were carried out at the B2PLYP-D3/ccpVDZ level. In addition to the theoretical studies, the experimental Fourier-transform infrared spectroscopy (FTIR) spectrum of the complex formed between SMX and MAA was compared with the theoretical FTIR spectrum. As a result of the studies, the monomer ratio and solvent environment in which the stable complex was formed were determined in the MIP studies carried out with the SMX template molecule and MAA monomer. The most stable template molecule–monomer ratio of the complex between SMX and MAA was determined to be 1:3, and the solvent medium in which the most stable geometry was formed was acetonitrile.