| dc.description |
The production cost, time, energy usage and membrane performance are the important broad aspects for
fabricating silica membranes. The aim of this study is to compare the calcination techniques between
conventional thermal processing (CTP) and rapid thermal processing (RTP) in producing pure silica
membranes using a-two step acid base catalyst method based on sol-gel process. Silica material
properties is also studied by looking at the several parameters such as chemical composition and surface
properties through different calcination methods (CTP and RTP). In fabricating silica membranes, the
calcination techniques were set at temperature 600oC and 4 layers for both CTP and RTP (CTP: 1oC
min-1 ramping/cooling rates, hold for 4 hours and RTP: without setting up ramping/cooling rates, hold
for 1 hour). From xerogel characterization, FTIR spectroscopy showed similar vibrational behaviour in
the wavelength 1500-700 cm-1 between sample calcined under CTP as well as RTP. However, the
deconvulation computation shows the silanol:siloxane concentration was 10% higher for RTP compare
to CTP on silica xerogels. Additionally, the morphology of these silica membranes show that silica
membranes fabricated using CTP method is thinner than RTP (~0.5 μm vs ~1.1 μm). It is due to
calcination time using RTP method was too short compare to CTP method. Therefore, the evaporation
process of solvent diluted in sols was not completely evaporated during calcination process and it then
automatically affects the membrane performance (9.72 to 6.94 and 1.63 to 0.63 kg m2 h-1 for feed 0; 0.3;
1; 3.5 %w/v artificial salt solution, for membranes samples calcined under CTP and RTP method,
respectively).
Keywords: calcination method, sol gel, acid-base catalyst, CTP & RTP methods |
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