Featured Research

from universities, journals, and other organizations

Ultrasound Can Drain The Color From Toxic Dyes

Date:
May 7, 2008
Source:
Inderscience Publishers
Summary:
Brightly colored dyes such as the shimmering Congo Red commonly used in silk clothing manufacture are notoriously difficult to dispose of in an environmentally benign way.

Brightly colored dyes such as the shimmering Congo Red commonly used in silk clothing manufacture are notoriously difficult to dispose of in an environmentally benign way.

Related Articles


Congo Red is an azo dye, it is toxic to many organisms and is a suspected carcinogen and mutagen. To give it its full name it is the disodium salt of 3,3' - (1E,1'E) - biphenyl - 4,4' - diylbis(diazene - 2, 1 - diyl)bis(4 - aminonaphthalene - 1 - sulfonate). It is a benzidine-based anionic disazo dye. Benzidine and Congo Red are, however, banned in many countries because of health concerns. But, it is still widely used in several countries.

Apparently it is used not only to dye silk a gorgeous red, but cleverly adds a second shimmering color and rending the red silk shot through with yellow. It also represents a significant effluent problem along with related dyes from textiles, printing and dyeing, paper, rubber, and plastic industries. Its structural stability makes it highly resistant to biodegradation, and obviously its bright color and toxicity are entirely undesirable in the environment.

Srinivas Sistla and Suresh Chintalapati, from Hyderabad, India, explain a new approach to degrading Congo Red based on ultrasound.

The researchers point out that advanced oxidation processes (AOP) are currently being developed for remediation of contaminated effluent because they generate no hazardous sludge. Oxidative degradation is based on free radical attack using powerful oxidants. However, Sistla and Chintalapati suggest that sonolysis, break down of an organic compound with ultrasound, has so far been investigated only rarely as an alternative remediation technology. Under well-established 'extreme' conditions, materials irradiated with sound at frequencies around 50 kHz are essentially ripped apart by the formation of free radicals, say the researchers. Carbon dioxide and water are the usual products, although with the case of azo dyes, nitrogen would also feature in the byproducts.

Sonication of Congo Red in the aqueous phase with 50 kHz ultrasound transforms it into a milieu of less toxic intermediates that can then be broken down still further by conventional industrial waste water biodegradation treatment. As a proof of principle, the researchers suggest that the combination of ultrasound and biodegradation could allow the color to be removed from dye-contaminated industrial effluent effectively and the toxicity reduced to negligible levels. "The results obtained from this study revealed the ability of ultrasonic irradiation to transform the aromatic inhibitory compounds to less toxic intermediates, which can be further utilized in aerobic/anaerobic oxidation," the researchers conclude.


Story Source:

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


Journal Reference:

  1. Rajeev Jain, Shalini Sikarwar. Photocatalytic and adsorption studies on the removal of dye Congo red from wastewater. International Journal of Environment and Pollution, 2006; 27 (1/2/3): 158-178 [link]

Cite This Page:

Inderscience Publishers. "Ultrasound Can Drain The Color From Toxic Dyes." ScienceDaily. ScienceDaily, 7 May 2008. <www.sciencedaily.com/releases/2008/05/080506100325.htm>.
Inderscience Publishers. (2008, May 7). Ultrasound Can Drain The Color From Toxic Dyes. ScienceDaily. Retrieved March 29, 2015 from www.sciencedaily.com/releases/2008/05/080506100325.htm
Inderscience Publishers. "Ultrasound Can Drain The Color From Toxic Dyes." ScienceDaily. www.sciencedaily.com/releases/2008/05/080506100325.htm (accessed March 29, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Sunday, March 29, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Arthropod Fossil Might Be Relative Of Spiders, Scorpions

New Arthropod Fossil Might Be Relative Of Spiders, Scorpions

Newsy (Mar. 29, 2015) A 508-million-year-old arthropod that swam in the Cambrian seas is thought to share a common ancestor with spiders and scorpions. Video provided by Newsy
Powered by NewsLook.com
Vietnam Rice Boom Piles Pressure on Farmers and the Environment

Vietnam Rice Boom Piles Pressure on Farmers and the Environment

AFP (Mar. 29, 2015) Vietnam&apos;s drive to become the world&apos;s leading rice exporter is pushing farmers in the fertile Mekong Delta to the brink, say experts, with mounting costs to the environment. Duration: 02:35 Video provided by AFP
Powered by NewsLook.com
Raw: New Eruptions at Colima Volcano in Mexico

Raw: New Eruptions at Colima Volcano in Mexico

AP (Mar. 28, 2015) The Colima Volcano in western Mexico sent large columns of ash up into the air on Saturday. (March 28) Video provided by AP
Powered by NewsLook.com
Antarctic Ice Is Melting Faster Than Ever

Antarctic Ice Is Melting Faster Than Ever

Newsy (Mar. 27, 2015) A new study of nearly two decades of satellite data shows Antarctic ice shelves are losing more mass faster every year. Video provided by Newsy
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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