Silica modified with 2,6-diacetylpyridine-monosalicyloylhydrazone: A novel and selective organic-inorganic sorbent for separation of molybdenum ions in a newly designed reactor

A novel silica based organic-inorganic hybrid material (DAPSH-APTES@SiO2) was synthesized by grafting of 2,6-diacetylpyridine-monosalicyloylhydrazone (DAPSH) on amino-functionalized silica (APTES@SiO2), and applied as a selective solid sorbent for on-line separation of molybdenum using a newly designed reactor. The material was characterized using Scanning electron microscopy (SEM), C-13 CPMAS NMR spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, elemental analysis, BET surface area analysis and X-ray diffraction (XRD) studies. Several parameters concerning adsorption behavior, including sample pH, sample volume, flow rate, type of eluent, and effect of ionic interference, etc. were evaluated for effective and selective adsorption of molybdenum. The Langmuir model and Freundlich model have been used to interpret the adsorption of Mo(VI) ions on the surface of sorbent. The precision calculated as relative standard deviation (n = 5) was less than 3% for molybdenum concentration of 2.0 mu g mL(-1) with the detection limit of 0.5 ng mL(-1) using flame atomic absorption spectrometry (FAAS). The developed method was successfully applied for highly sensitive and selective determination of molybdenum in water samples and plant food stuffs. The accuracy was validated using a certified reference material (CRM) with satisfactory results. In addition, a novel reactor with automated modes opens up a new avenue for the effective and large scale extraction of molybdenum using recyclable organic-inorganic hybrid sorbent in short duration of time. (C) 2012 Elsevier B.V. All rights reserved.