title: Synthesis, characterization, and sorption properties of silica gel-immobilized Schiff base derivative.
abstract: Silica gel was derivatized with benzophenone 4-aminobenzoylhydrazone (BAH), a Schiff base derivative, after silanization of silica by 3-chloropropyltrimethoxysilane (CPTS) by using a reported method. Characterization of the surface modification was confirmed through infrared spectroscopy, thermogravimetry, and elemental analysis. The immobilized surface was used for Cu(II), Ni(II), Zn(II), and Co(II) sorption from aqueous solutions. The influence of the amount of sorbent, ion concentration, pH, and temperature was investigated. The sorption data followed Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms. The mean sorption energy (E) of benzophenone 4-aminobenzoylhydrazone (BAH) immobilization onto silica gel was calculated from D-R isotherms, indicating a chemical sorption mode for four cations. Thermodynamic parameters, i.e., DeltaG, DeltaS, and DeltaH, were also calculated for the system. From these parameters, DeltaH values were found to be endothermic: 27.0, 22.7, 32.6, and 34.6 kJ mol(-1) for Cu(II), Ni(II), Co(II), and Zn(II) metal ions, respectively. DeltaS values were calculated to be positive for the sorption of the same sequence of divalent cations onto sorbent. Negative DeltaG values indicated that the sorption process for these three metal ions onto immobilized silica gel is spontaneous.
authors.affiliation: Department of Chemistry, Selçuk University, Campus, 42031 Konya, Turkey. ihilalg@gmail.com
authors.forename: I Hilal
authors.initials: IH
authors.lastname: Gübbük
authors.forename: Ramazan
authors.initials: R
authors.lastname: Güp
authors.forename: Mustafa
authors.initials: M
authors.lastname: Ersöz
mesh_terms: D001577:Benzophenones / Q000138:chemical synthesis / Q000737:chemistry*; D002413:Cations, Divalent / Q000737:chemistry*; D006835:Hydrazones / Q000138:chemical synthesis / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy; D012545:Schiff Bases / Q000138:chemical synthesis* / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D058428:Silica Gel; D012822:Silicon Dioxide / Q000138:chemical synthesis* / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D001577:Benzophenones; D002413:Cations, Divalent; D006835:Hydrazones; D019216:Metals, Heavy; D012545:Schiff Bases; D012821:Silanes; C529264:benzophenone 4-aminobenzoylhydrazone; D058428:Silica Gel; D012822:Silicon Dioxide