Project Details
Abstract
Each existing method used for wastewater treatment has limitations and drawbacks. For example,
chemical precicipation and activated carbon adsorption merely transfers the pollutants from liquid phase
to solid phase, leading to secondary pollution. Filtration can hinder suspended solids but not microsolids
unless the use of polymer membranes with sufficiently small pore sizes. In that case, the efficiency and
economics will largely reduce due to the phenomena of membrane fouling and pore blockage. Biological
method can degrade organic pollutants in a greener manner; however, the degradation of some synthetic
organics is much slow, making the process efficient only under well controlled temperature and/or pH
environments. Photocatalysis under UV irradiation has received much attention recently due to no need of
the oxidants added, fast reaction, and low operating cost. However, the degradation rate will largely
decrease during the process because it essentially contains many successive chemical reactions. This
evitably increases the “time” cost. In this regards, more efficient treatment methods are highly desired.
In this project, a hybrid UV/photocatalysis and NF/UF process is proposed because this process has
the synergistic effect based on both single processes; for example, the level of pollutant in the retentate can
be maintained because water passes through the membrane, resulting into a nearly constant reaction rate.
Also, membrane self-cleaning is observed because the pollutant(s) adjacent to membrane surface can be
degraded by UV/photocatalysis, leading to the less membrane fouling. Several dyes with a molar mass
beyond 300 g/mol are selected here as model organic pollutants. In the first year, the parameters that are
defined in single process are first obtained including the apparent degradation rate constant and solute
rejection by the original and prepared membranes. The degradation of dye and flux decline in a hybrid
UV/photocatalysis with TiO2 suspension and NF/UF with original membrane is then tested. Moreover, the
TiO2/carbon nanotube (CNT) composite membrane with a diameter of 30 mm will be prepared and its
physicochemical properties including crystalline phase, absorption wavelength, surface structure, and pore
size are characterized. In the second year, the TiO2/CNT composite membrane with a diameter of 47 mm
is prepared. The reaction rate and flux decline in a hybrid UV/photocatalysis and NF/UF with TiO2/CNT
composite membrane are measured to check membrane self-cleaning ability. In the third year, a larger size
of TiO2/CNT composite membrane is prepared. Dynamic behavior of this hybrid process is then analyzed
and the operating parameters are optimized. Due to its high specific surface area and excellent
photocatalytic activity, TiO2/CNT is capable of facilitating photodegradation and NF/UF for organic
wastewater. It is hence expected that the present project allows us to realize the application potentials and
limitations of this hybrid process. The solutions that can overcome such limitations will be suggested.
Project IDs
Project ID:PB10501-2673
External Project ID:MOST103-2221-E182-073-MY3
External Project ID:MOST103-2221-E182-073-MY3
Status | Finished |
---|---|
Effective start/end date | 01/08/16 → 31/07/17 |
Keywords
- Photocatalysis
- Membrane filtration
- Organic wastewater
- TiO2 suspension
- TiO2-coated composite membrane
- TiO2/carbon nanotube-functionalized composite membrane
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