A hybrid molecular imprinted polymer (HMIP) obtained by the organic monomer 4-vinylpyridine (4-VP) and the inorganic precursor tetraethyl orthosilicate (TEOS) was synthesized for the selective extraction of urinary S-phenylmercapturic acid (u-SPMA), a biomarker of benzene exposure. The chemical and structural characterization of the synthetic adsorbent was performed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and textural analysis employing N2 adsorption-desorption isotherms. Selective and adsorptive performance of the imprinted polymers were evaluated by kinetic, isothermal, thermodynamic, and selectivity studies. The kinetic data were well adjusted to pseudo-second order and intraparticle diffusion models, leading to selectivity coefficient (K) value of 0.03 g mg-1 min-1 for HMIP. In addition, the adsorption isotherms were better described by the Sip model achieving a maximum adsorption capacity of 284.81 μg g-1 (at 288.15 K).

Ternary oxide silica-alumina-zirconia (SiO2/Al2O3/ZrO2) obtained by the sol-gel process was applied as novel adsorbent of ions in aqueous solution. Batch isotherms were performed using standard CuII, CdII and CaII solutions at variable pH and different concentrations. Adsorption capacity was best at weakly acidic pH. The maximum adsorption capacities were 2.28 mg g−1 for CaII, 9.89 mg g−1 for CdII, and 14.88 mg g−1 for CuII. The adsorption data fitted well to the single and dual-site Langmuir-Freundlich isotherm models. However, since the adsorption is very low in the sites with high energy, the single-site Langmuir-Freundlich provided a good fit as well. Whereas, the site responsible for the most ion adsorption was assigned to the Zr−OH group. A real sample of produced water was also tested. The new adsorbent showed a wide ability to retain many metal ions (alkali-earth, transition, and p-block metals) and even some anions were also caught by the adsorbent. The ternary oxide silica-alumina-zirconia was found to be a promising alternative adsorbent for metal ions in aqueous media.