Advertisement
Advertise Here
-
November 15, 2010 - DOI: 10.1021/CEN110210133806
[an error occurred while processing this directive]
Forensic Chemistry: A new method could increase the number of explosives detected by airport screeners.
Trade: U.S. companies complain of market dumping by China.
Layoffs follow similar moves by Amgen, AstraZeneca.
Environment: Ban to halt export of hazardous waste to developing world.
Penrose (Parney) Albright will direct DOE national lab.
Toxic Exposure: Mercury isotopes in human hair illuminate dietary and industrial sources.
Cancer Biochemistry: Mass spectrometry follows the metabolism of very long fatty acids in cancer cells.
Every year, factories producing a key ingredient used in dyes and detergent brighteners generate 500 billion gal of toxic wastewater. Now Chinese researchers have developed a process to turn that waste into a drug used to treat multi-drug resistant tuberculosis (Environ. Sci. Technol., DOI: 10.1021/es101950k).
Industrial-scale production of dye-precursor 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNS) creates byproducts that are generally tough to break down and non-biodegradable, such as p-nitrotoluene-o-sulfonic acid. As a result, current DNS waste treatments are energy-intensive and costly, says Xiaobin Fan, a chemical engineer at Tianjin University.
Fan and his colleagues wanted to do better. First, they analyzed the components in the wastewater and found that all the contaminants had a basic structure in common: a substituted aromatic sulfonic acid. They then thought up ways to convert chemicals with that basic structure into something useful.
The researchers came up with a process, which involves an oxidation, reduction, and sodium hydroxide treatment step, to convert more than 85% of the wastewater's contaminants into 4-amino-2-hydroxybenzoic acid (paramycin), which is part of cocktail treatments for multi-drug-resistant tuberculosis. Each year, drug-makers produce 500 tons of paramycin. But it also has non-medical uses: Chemical manufacturers synthesize over 1 million tons of the compound for use in the production of polymers, pesticides, and alumina.
Treating DNS wastewater normally costs about $4/m3 of wastewater, but this new process can net $77 worth of valuable chemicals per m3 of wastewater, according to the researcher's calculations. This route to paramycin is also more environmentally friendly than existing methods, producing less waste per amount of paramycin produced. "It solves environmental problems and obtains economic benefits at the same time," says Fan.
The Huayu Chemical Company in China, a major world supplier of DNS, cooperated with the researchers on the project and has adopted the new process on a pilot-scale to optimize the technique.
Martin Mulvihill, a chemist with the University of California, Berkeley's Center for Green Chemistry, praised the researchers for evaluating the new process's environmental impact to ensure that it was less wasteful than existing paramycin routes: "That really takes it above other work that just looks at using a waste product to make something of value."
ACS is the leading employment source for recruiting scientific professionals. ACS Careers and C&EN Classifieds provide employers direct access to scientific talent both in print and online. Jobseekers | Employers
Join more than 161,000 professionals in the chemical sciences world-wide, as a member of the American Chemical Society.
» Join Now!