Synthesis, Characterization and Applications of Sol-Gel Derived Zirconium Oxide Adsorbent Powder: Removal from Aqueous Solution of Phenol and p-Chlorophenol

Authors: MURAT AKARSU, HİKMET SAYILKAN, ŞADİYE ŞENER, FUNDA SAYILKAN, ERTUĞRUL ARPAÇ

Abstract: Adsorbent powders were prepared from the uncatalysed hydrolysis-condensation reactions of different complexes that were synthesized by the reactions of Zr(OPr^{n})_{4} with different chelating ligands (such as allylacetic acid [AAH], vinylacetic acid [VAH] and citraconic acid [CAH]). The complex products were characterized by FT-IR, ^{1}H-NMR and ^{13}C-NMR spectra. The maximum combination ratios of AAH/Zr(OPr^{n})_{4}, VAH/Zr(OPr^{n})_{4} and CAH/Zr(OPr^{n})_{4} were 1.7, 0.9 and 1.3, respectively. The hydrolysis-condensation products of these complexes were calcinated at 900 °C and half of them were coated with 3-glycidyloxypropyltrimethoxysilane (GLYMO). The surface area and average pore diameter of the powders were estimated by the analysis of adsorption/desorption BET isotherm data. The adsorption capacities of these powders for aqueous phenol and p-chlorophenol were calculated following spectrophotometric determination. Phenol and p-chlorophenol adsorption on all of the GLYMO-coated adsorbents were satisfactory, e.g., the adsorbent obtained from the hydrolyzed, calcinated and GLYMO-coated form of Zr(OPr^{n})_{2.3}(AA)_{1.7} adsorbed 63% of phenol while the uncoated form adsorbed only 10%. The adsorption isotherm has been determined and data have been analyzed according to the Freundlich model.

Keywords: adsorbent, adsorption, coating, sol-gel process, zirconium alkoxides.

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