Ion-imprinted modified molecular sieves show the efficient selective adsorption of chromium(vi) from aqueous solutions.

Molecular sieve 5A was modified with (3-aminopropyl) triethoxysilane (APTES) as the support matrix, on which 4-VP was used as the ionic imprinting group. The as-prepared IIZMS-APTES was applied as the adsorbent for the recovery of chromium(vi) from aqueous solutions. The adsorbent was characterized via Fourier transform infrared spectroscopy (FT-IR), scanning electronic microscopy (SEM), and X-ray diffraction (XRD). The influences of adsorption time, concentration of the ions, initial pH, and temperature on the adsorption performance to Cr(vi) were investigated. The selectivity and reusability of IIZMS-APTES are also evaluated. The results showed that the maximum adsorption capacity reached 56.46 mg g -1 when the initial concentration of metal ions was at 100 mg L -1 at pH 2 and 30 °C. The adsorption process followed the pseudo-second-order kinetic model and Langmuir adsorption isotherm model. The IIZMS-APTES exhibits an efficient selective adsorption of Cr(vi) from aqueous solutions.