Preparation of by-product titanium dioxide (TiO2) from coagulated Sludge produced by locally made titanium tetrachloride (TiCl4) of leachate landfill for potential photocatalyst applications
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Date
2019-07
Authors
Fathin Azwina Binti Faisol Azani
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Abstract
The photodegradation of dye methylene blue (MB) by titanium dioxide from leachate sludge were
prepared by adding coagulant of TiCl4 and chitosan initial preparation for sample then followed
by calcination at different temperature was studied to examine for potential of photocatalytic
activity. Synthesis process was carried out by adjusting solution pH to 4. The experiment was
performed by design of experiment (DOE). The parameters involved were calcination temperature
(400 to 800 °C), calcination time (6 to 12 hours) and TiCl4 dosage (800 mg/L to 1200 mg/L)
while the responses were percentage of weight loss and optical bandgap energy. Various
characterization method had been carried out such as X-Ray Diffraction (XRD), Scanning
Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDX), X-ray
Fluorescence Spectrometer (XRF), Inductively Coupled Plasma- Optical Emission Spectrometry
(ICP-OES) and UV-Visible Spectrophotometery. From the experimental results, the highest
percentage of weight loss of 91.6 % was achieved at the calcination temperature of 800°C, 12
hours of calcination time and TiCl4 dosage of 1200mg/L ( r u n # 9 ) while lowest w e i g h t
p e r c e n t l o s t w a s a c h i e v e d a t ( r u n # 7 ) . O n t h e o t h e r h a n d , t h e l o w e s t
o p t i c a l bandgap energy, w h i c h w a s 2 . 7 e V ( U V - V i s ) can be obtained when
calcination temperature was 800 °C, calcination time of 12 hours and TiCl4 dosage is 800mg/L
(run #10). In contrast, the highest optical bandgap was achieved at temperature 600°C at 9 hours (run #1). The DOE statistical analysis showed that calcination temperature was the most
significant parameter, followed by calcination time and TiCl4 dosage. Characterization of the
calcined TiO2 was performed using X-ray diffraction (XRD), and Scanning Electron Microscopy
(SEM). The highest weight loss (run #8) showed that the organic compounds present decomposed
at 800°C with calcination time of about 12 hours. The XRD results showed that the presence of
TiO2 (anatase) only occurred when the calcination temperature of the precursor at 800°C and above
this, rutile phase was observed. The photocatalytic activity of 2.7 eV TiO2 sludge powder was
determined by the photodegradation of MB dye under UV light. From the photocatalytic
experiments, the TiO2 by-product can degrade the MB about 76%. Hence, this new approach on
reuse of sludge from leachate can provide cost-effective and eco-friendly approach for TiO2
production photocatalysts as the by-product TiO2 from leachate treated with TiCl4.