The Development of an Ultrasonic Hypochlorous Acidic Humidifier for Disinfecting Application
Dr.
Kenji Uchino
Dr.
Yongkang Gao
Materials
Research Institute
The
Pennsylvania State University
University
Park, PA 16802
I. Summary
In order to effectively respond to potential biological attacks with foreign animal diseases, approaches like antiviral, antibacterial treatments may be very useful in the short term for stopping the spread of a disease agent. Their use may make it less necessary to resort to depopulation of all contact animals. Also, they are very useful for rapid disposal of carcasses of infected and contact animals and immediate disinfection of contaminated premises, vehicles and equipment.
Recent studies on acidic electrolytic water show that
it is very effective as disinfectant against bacteria, fungi, viruses and
permanent forms. Hypochlorous acid, as the principal disinfectant, is formed in
the electrolytic cell from the chloride contained in the water. Due to its oxidizing potential
the hypochlorous acid transfers atomic oxygen in the form of a
"radical" to the microorganism, which destroys it finally. Table 1 1shows how effectively the
microorganisms can be inhibited or destroyed by the active substance
hypochlorous acid. All of the bacteria and viruses were destroyed or
inactivated after the instrument had been exposed to acidic electrolytic water
for 5 min. Hypochlorous acid was found to be nonirritant to skin and
environment, nontoxic to cells, and nonmutagenic. Hypochlorous acid is rated safe for transportation and storage,
and does not require containment or ventilation. The hypochlorous acid
treatment systems have significant advantages over the other known disinfectant
methods. The cost of hypochlorous acid systems is significantly less than or comparable to other methods,
especially considering the risks inherent in the significant, sometimes even
potentially catastrophic, disadvantages of the other methods.
Piezoelectric vibrators are
forming a new field between electronic and structural ceramics 1-5.The
ultrasonic air humidification technology uses high-frequency vibration to
generate a micro-fine mist. A fan blows the mist into the room air where it
immediately evaporates. It is noticed that ultrasonic humidifier can generate
not only pure water mist but also solution mist. Ultrasonic humidifiers
require little power. Ultrasonic humidifiers rely on an adiabatic
process that generates a water mist without raising its temperature. This
process requires much less energy than alternative systems that boil water in a
reservoir, use infrared light to reduce the surface tension of a pool of water,
or use rotating disks to sling a spray of droplets.
The unique
combination proposed in this report of ultrasonic air humidification with the disinfectant
hypochlorous acid opens the wide possibility of effectively and safely destroy
various airborne virus and bacteria and immediately disinfect contaminated
settings. This technique is especially promising for immediate response for
terrorism biological attack. Figure 1 gives the conceptual design of ultrasonic
hypochlorous acidic humidifier. The top part is electrolytic cell. After
applying a current through and adjusting suitable pH range, the strong
disinfectant hypochlorous acid can be generated and feed into the water tank.
Special care is given for vapor spreading by leaving 20mm distance between the
electrolytic cell and water tank. One or several of ultrasonic transducers sit
inside of the water tank and generate disinfecting vapor at room temperature
without boiling it.
The two major advantages
of our proposed hypochlorous acidic humidifier are as following: 1) Safety. No
special care is needed for the storage and transportation of the hypochlorous
acidic water. The acidic electrolytic water maintains the strong disinfecting
capability for around one day and no need to clean it later. 2) High
efficiency. The smaller the disinfectant droplets are, the higher the airborne
“killing” ability is. In this sense, high frequency ultrasonic humidifier is
the most suitable technique to generate uniformly micrometer-sized droplets,
which can be evaporated immediately. In addition, Aiming at field application
small portable equipment can be developed also.
The new availability of hypochlorous acid vapor, combined with the solid technology of ultrasonic humidification system, can now become nothing less than the definitive solution to a serious, expanding national and international health dilemma. The disinfecting quality, safety and efficiency can be effectively and economically assured.
Table1 The effectiveness of hypochlorous acid against various microorganisms6-8
|
Microorganism |
Time |
Microorganism |
Time |
|
Staphylococcus aureus (MSSA) |
< 10 sec |
Candida albicans |
<15 sec |
|
Staphylococcus aureus (MRSA) |
< 10 sec |
Aspergillus terreus |
<15 sec |
|
S. epidermidis |
< 10 sec |
Trichosporon |
<15 sec |
|
Enterococcus faecalis |
< 10 sec |
|
|
|
Escherichia coli 0-157:H7 |
< 10 sec |
M. avium |
<1 min |
|
Klebsiella pneumoniae |
< 10 sec |
Cryptococcus neoformans |
<1 min |
|
Pseudomonas aeruginosa |
< 10 sec |
Mycobacterium tuberculosus |
<2.5 min |
|
Salmonella typhi |
< 10 sec |
M. fortuitum |
<2.5 min |
|
Serratia marcescens |
< 10 sec |
|
|
|
Vibrio parahaemolyticus |
< 10 sec |
Bacillus cereus |
<5 min |