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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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.
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