Photocatalytic Removal Of Phenol Using Titanium Dioxide (Tio2) In Fluidized Bed Reactor
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Date
2012
Authors
Tan, Yong Nian
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Fluorinated titanium dioxide (F-TiO2) and immobilized F-TiO2 were
synthesized by sonication-hydrothermal method and binding method. Fluorine
doping, immobilization, hydrothermal method and fluidized bed reactor used in this
study. The samples were characterized by X-ray diffraction (XRD), Brunauer-
Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), energy
dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM).
The photocatalytic degradation of phenol using the prepared photocatalyst was
evaluated under UV light irradiation in batch mode fluidized bed reactor. Based on
the XRD patterns, all the diffraction peaks of the F-TiO2 photocatalysts corresponded
to the anatase phase of TiO2. The surface morphology of F-TiO2 observed by both
SEM and TEM was uniformly distributed and the largest of BET surface area, total
pore volume, and average pore size of F-TiO2 at the Ti:F molar ratio of 0.15 under
hydrothermal duration of 10 h. The presence of F, Ti, and O on the surface of F-TiO2
was confirmed by EDX analysis. The optimum composition of the photocatalyst
comprising F-TiO2, quartz sand, and colloidal silica was 1:1.5:1. Based on TEM
images, F-TiO2 prepared in the Ti:F molar ratio of 0.15 under hydrothermal duration
of 10 hours (8.4 nm) had a relatively smaller crystalline size compared to the
supported F-TiO2 (45-60 nm). F-TiO2 produced at the Ti:F molar ratio of 0.15 for
hydrothermal duration of 10 h showed the highest degradation rate of phenol. The
results for the studied operating parameters were: the optimal catalyst loading was
found to be 4 g/L; the optimum initial phenol concentration was observed to be 20
mg/L; the air flow rate gave an optimum value of 2 L/min; the presence of metal
cations impeded the photocatalytic activity of photocatalyst in the order of K+ >
Ca2+ > Zn2+; the addition of inorganic anions also inhibited the photocatalytic
reaction in the order of SO4 2- > HCO3 - > NO3 -. Immobilized F-TiO2 gave the better
photocatalytic activity as compared to commercial Degussa TiO2 P25. The
photocatalytic degradation of phenol fitted well with pseudo first order kinetic model
with its reaction rate constant, k equal to 2.19 mg/L.min and the adsorption constant,
K equal to 0.0305 L/mg, respectively. Response surface methodology (RSM) based
on the central composite design (CCD) used to optimize the photocatalytic
degradation of phenol. The optimum phenol photodegradation was achieved in 105
minutes at the catalyst loading of 4 g/L, air flow rate of 2 L/min, and initial phenol
concentration of 20 mg/L.
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Keywords
Photocatalytic removal of phenol using , titanium dioxide in fluidized bed reactor