Featured Research

from universities, journals, and other organizations

Ultrasound Cleans Ceramic Filters: Could Aid Water Treatment

Date:
April 11, 2002
Source:
Ohio State University
Summary:
Engineers at Ohio State University have discovered how to clean high-tech ceramic water filters at low cost with ultrasound. Though early in its development, this technology may one day enable water treatment plants to purify water with ceramic membrane filters instead of harsh chemicals.

COLUMBUS, Ohio -- Engineers at Ohio State University have discovered how to clean high-tech ceramic water filters at low cost with ultrasound.

Though early in its development, this technology may one day enable water treatment plants to purify water with ceramic membrane filters instead of harsh chemicals.

Linda Weavers and Harold Walker, both assistant professors of civil and environmental engineering and geodetic science, and doctoral students Dong Chen and Mikko Lamminen described their ultrasonic cleaning technique April 10 in a poster at the American Chemical Society meeting in Orlando.

"If water treatment plants could clean water with membrane filters, they could minimize the cost, safety and disposal issues associated with the use of harsh chemicals," Walker said.

As an alternative to chemicals, researchers are studying ceramic membrane filters -- honeycomb-like networks of tiny channels separated by thin ceramic films, or membranes. When water flows through the channels, the membranes act as sieves to catch contaminants such as clay, iron oxide, bacteria and viruses. The problem: over time, the membranes become clogged with contaminants, and must be cleaned.

Weavers and Walker took note of recent research involving ultrasound and bubbles. The idea, most recently reported by scientists at Oak Ridge National Laboratory and their colleagues, is that sound waves can form and collapse bubbles inside a liquid, releasing heat and energy.

To test whether collapsing bubbles could clean a ceramic filter, the engineers submerged a filter in water that contained latex and silica particles. They used particles in a range of sizes to mimic the contaminants found in water treatment.

They used an ultrasonic probe to vibrate the water at 20 kilohertz, or 20,000 vibrations per second -- a low frequency that is easily obtainable with typical ultrasound equipment. For example, the fetal ultrasound tests that women undergo during pregnancy employ much higher frequencies -- on the order of 10 megahertz, or 10 million vibrations per second.

But that doesn't mean a 20 kilohertz probe is less powerful, Weavers explained. "Frequency has nothing to do with power. Think of it as bass sounds versus soprano sounds. Both can be louder or softer. Whether a sound is bass or soprano depends on frequency, whereas loudness and softness depend on power," she said.

The 20 kilohertz vibrations caused bubbles for form and collapse, and kept the ceramic filter clean.

"The bubbles seemed to scour the surface of the filter," Weavers said. "Where the bubbles collapsed, tiny water jets formed and flushed away the contaminants."

Though the engineers are still not certain exactly how the process works, Weavers suspects that the jets sprang from vibrational nodes -- locations along the surface of the filter where ultrasonic waves merge together and magnify each other.

With ultrasound as a cleaning method, water treatment plants wouldn't have to remove filters from use to clean them, Walker said. Loosened contaminants would wash away in an exhaust flow separate from the clean water.

"If you left the ultrasound running, you could clean a filter while it was still in use, and keep it from ever getting clogged in the first place," Weavers added. The engineers have just applied for additional funding for further laboratory tests.

If all goes well, Walker said, the technology may be ready for full-scale testing in a water treatment plant within the next few years.

The Ohio Water Development Authority and the United States Geological Survey funded this project.


Story Source:

The above story is based on materials provided by Ohio State University. Note: Materials may be edited for content and length.


Cite This Page:

Ohio State University. "Ultrasound Cleans Ceramic Filters: Could Aid Water Treatment." ScienceDaily. ScienceDaily, 11 April 2002. <www.sciencedaily.com/releases/2002/04/020411071737.htm>.
Ohio State University. (2002, April 11). Ultrasound Cleans Ceramic Filters: Could Aid Water Treatment. ScienceDaily. Retrieved September 21, 2014 from www.sciencedaily.com/releases/2002/04/020411071737.htm
Ohio State University. "Ultrasound Cleans Ceramic Filters: Could Aid Water Treatment." ScienceDaily. www.sciencedaily.com/releases/2002/04/020411071737.htm (accessed September 21, 2014).

Share This



More Matter & Energy News

Sunday, September 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

What This MIT Sensor Could Mean For The Future Of Robotics

What This MIT Sensor Could Mean For The Future Of Robotics

Newsy (Sep. 20, 2014) MIT researchers developed a light-based sensor that gives robots 100 times the sensitivity of a human finger, allowing for "unprecedented dexterity." Video provided by Newsy
Powered by NewsLook.com
MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
Powered by NewsLook.com
Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins