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Synthesis and characterization of a novel Schiff-base/SBA-15 nanoadsorbent for removal of methylene blue from aqueous solutions
Bardajee, G.R.; Hooshyar, Z. & Shahidi, F.E.
Abstract
A novel Schiff-base/SBA-15 nanoadsorbent
was successfully synthesized by the reaction of salicylaldehyde
and (3-aminopropyl) trimethoxysilane in methanol
and subsequent grafting with SBA-15. The morphology
and structures of the as-synthesized Schiff-base/SBA-15
nanoadsorbent were characterized by powder X-ray diffraction,
transmission electron microscopy, Fourier transform
infrared spectroscopy, thermo-gravimetric analysis,
and N2 adsorption/desorption isotherms. The obtained
Schiff-base/SBA-15 nanoadsorbent was used for the
removal of methylene blue (MB) from aqueous solutions.
The effects of various parameters such as temperature,
concentration, pH, and contact time were examined, and
optimal experimental conditions were determined. The
equilibrium isotherms were conducted using Freundlich
and Langmuir models. The pseudo-first-order, pseudosecond-
order, and intraparticle diffusion models were used
to fit adsorption data in the kinetic studies. The thermodynamic
parameters such as the standard enthalpy, standard
entropy, and standard free energy were evaluated. The
obtained results indicated that the Schiff-base/SBA-15
nanoadsorbent is an efficient adsorbent for removing MB.
Keywords
Schiff-base; SBA-15; Nanoadsorbent; Methylene blue; Kinetic model
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