Panasonic Develops Highly Effective Water Purification System Us

Panasonic Develops Highly Effective Water Purification System Using New Unique
Photocatalyst 
Osaka, Aug 5, 2013 - (JCN Newswire) -  Panasonic Corporation today announced
that it has developed a highly effective water purification system using a
newly developed photocatalyst. This system is capable of effective
detoxification of polluted water(1) by harmful heavy metals, such as arsenic,
chromium, and persistent organic matter at a reaction rate of up to 100 times
that of conventional methods(2). This developed photocatalyst has a unique
structure and is easy to collect from the polluted water after the
detoxification and is recyclable. Through this development, a water
purification system which is small size and isolated from municipal water
networks can be realized, making is suitable for developing countries, where
safe and low cost drinking water is needed. 
Increasing demands and shortage of clean drinking water resources due to the
rapid development of industrialization, population growth and long-term
droughts have become a global issue. In polluted areas, drinking water may
contain metal pollutants at levels more than double international standards.
The slurry photocatalytic water treatment technology(3) has the potential to
resolve these problems that especially occur in contaminated groundwater since
this technology efficiently reduces the toxicity of harmful pollutants by a
maximum of 99.99%: trivalent arsenic and hexavalent chromium are converted into
less harmful chemicals. As no consumption of chemical materials is carried out
during the photocatalytic water treatment, the technology has a lower impact on
the environmental in comparison to conventional chemical water treatments. 
The developed technology has the following features: 
- The separation rate of the particulate synthetic photocatalyst from water is
optimized by means of the designing of surface physicochemical properties of
the photocatalyst. 
- The photocatalyst possesses a large surface-area to volume-ratio which
contributes the efficient detoxification of the harmful pollutants. Throughput
of water treatment is thoroughly enhanced by this photocatalyst incorporated in
the slurry photocatalytic water treatment technology, by 50 times in the case
of arsenic pollutants and by 100 times in the case of persistent organic
materials. 
- Solar UV light is utilized as a light source for the slurry photocatalytic
water treatment technology, making a low cost and environmentally friendly
treatment system. 
This development is based on the following new technologies:
1. Synthesis technology of the photocatalyst by utilizing the inherent
electrostatic interaction between two particles
2. Slurry technology to control the transition between the particulate
photocatalyst aggregation and the suspension. 
Panasonic holds 10 Japanese patents and 6 overseas patents, including pending
application, for this development. 
A part of this technology has been demonstrated in the joint research subjects
with the Department of Chemical Engineering, Indian Institute of Science in
Bangalore, India. 
More on the Technology 
1. Synthesis technology of the photocatalyst by utilizing the inherent
electrostatic interaction between two particles 
The fixation of the particulate photocatalyst on a large inert substrate
reduces the surface of the photocatalytic active site and also enlarges the
mass transfer limitation of pollutants to the photocatalytic active site since
binder chemicals used for the fixation of particulate photocatalysts are often
deposited on the surface of photocatalysts, resulting in the decrease of the
surface active site. Instead of binder chemicals, the developed technology uses
the attractive force originated from electrostatic interaction. This force we
have found out is specific to the combination between nanoparticulate TiO2
photocatalyst and a particular type of microparticulate zeolite. The TiO2
photocatalyst bound to the zeolite maintains the inherent amount of
photocatalytic active site since there is no inhibitor at the interface between
the two particles. 
2. Slurry technology to control the transition between the particulate
photocatalyst aggregation and the suspension. Since the TiO2 photocatalyst was
weakly bound to the surface of the zeolite, TiO2 photocatalysts could be
desorbed from the surface of the zeolite by a simple agitation of the slurry
solution. When the agitation is stopped, TiO2 photocatalysts could be bound to
the surface of the zeolite again. This behavior has a responsibility for the
fact that the photocatalyst possesses both a large surface active site and the
separation feasibility from the water. 
Notes 
(1) effective detoxification of polluted water
Trivalent arsenic or hexavalent chromium is converted into the less harmful
pollutant of pentavalent arsenic or trivalent chromium respectively by the
photocatalytic reaction. In case of organic pollutants, a complete
mineralization without creating any secondary pollutant takes place. 
(2) Conventional methods
Thin films of photocatalyst originated from sol-gel mixed with particulate
photocatalysts are prepared on a large inert substrate. The fixation of the
photocatalysts results in increasing the difficulty in terms of the reaction
efficiency.
(3) Slurry photocatalytic water treatment technology
During the detoxifying process the particulate photocatalysts are suspended in
the water to be treated and then separated from the water to be reuse by an
automatic transfer system. The post separation of the particulate
photocatalysts had been the major obstacle toward the practical application so
far. 
About Panasonic 
Panasonic Corporation is a worldwide leader in the development and engineering
of electronic technologies and solutions for customers in residential,
non-residential, mobility and personal applications. Since its founding in
1918, the company has expanded globally and now operates over 500 consolidated
companies worldwide, recording consolidated net sales of 7.30 trillion yen for
the year ended March 31, 2013. Committed to pursuing new value through
innovation across divisional lines, the company strives to create a better life
and a better world for its customers. For more information about Panasonic,
please visit the company's website at http://panasonic.net/ . 
Contact: 
Tokyo Public Relations Office
Panasonic Corporation
Tel: +81-3-3574-5664 Fax: 03-3574-5699
Panasonic News Bureau
Tel: +81-3-3542-6205 Fax: 03-3542-9018 
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