الفهرس 
Introduction
Chemical properties and modification of the surface of silica gelOnly 14 pages are availabe for public view
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Abstract
The method was presented for the preparation of the porous silica which reacted with H3BO3 in the ratio Si:B = 1:9 . Then, it was chemically modified with gcsaminopropyltrimethoxysilane to obtain modified amino glass silica. Three product solid phase extractors were successfully synthesized according to physical adsorption and chemical immobilization binding techniques 2acetyl pyridine (phase I) , 2acetyl furane (phase II) and 2acetyl thiophene (phase III). The preconcentration and separation of heavy metal ions, viz. Cu2+, Zn2+, Fe3+, Pb2+, Mn2+, Co2+, Ni2+, Cd2+ and Hg2+ were described. The three phases sorbs quantitatively about (98.599.1 and 97.899.2% for the phase I, phase II and phase III) at pH 78 for all metal ions except Fe3+ which sorbs at pH =1 . The adsorbent and its formed metal chelates were characterized by flame atomic absorption spectrometry, IR, Potentiometric titrations, Thermogravimetric analysis (TGA and DrTGA), surface area and C, H, N, S. The sorption capacity varied from 0.048 to 0.418 mmolg1 for phase I, from 0.062to 0.358 mmolg1 for phase II and from 0.059 to 0.439 mmolg1 for phase III . Desorption was found to be quantitative with 0.51 M HCl by batch and column technique. The percentage recovery values from the water samples in the studied metal ions ranged from 93.6 97.2 % .The presence of higher concentration of Na+ ,K+ , Mg2+ and Ca2+ showed insignificant role or no matrix effect on such selective extraction process due to their negligible values of removal by these modified silica phases specially in natural water samples.