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NASA Testing Breakthrough In Water Safety

Original Source: http://www.treehugger.com
Author: Jerry James Stone
Original Publication Date: 16 September 2009

Photo courtesy of Science Daily/NASA

NASA and University of Utah chemists are developing advanced tech for testing the drinkability of water.

The process just began a six month run aboard the International Space Station. Water will be sampled either from the Space Station’s or Shuttle’s galley using a syringe. It is then forced through a chemically-imbued membrane which changes color based on toxicity.

Man, astronauts sure do have a tough gig. They are either drinking processed urine or waste water. Whatever happened to plain ol’ Tang?

Fact is, no one wants a stomach bug but getting Montezuma’s revenge in space has to totally suck it. The process itself will take about two-minutes. It checks drinking water for iodine and silver which are to used kill unwanted microbes. U.S. spacecrafts use iodine where Russians use silver while both methods are used in the International Space Station.

“Our focus was to develop a small, simple, low-cost testing system that uses a handheld device, doesn’t consume materials or generate waste, takes minimal astronaut time, is safe and works in microgravity,” says Porter.

A spinoff test is being modified for checking arsenic in places like Bangladesh. Low cost versions are also being considered for other pollutants like “chromium, cadmium, nickel and other heavy metals” said Lorraine Siperko, a senior research scientist in Porter’s laboratory.

Using a commercially available handheld sensor, the membrane will be examined for color. The same device is used for measuring color and glossiness of automobile paint.

Currently “they bring water back on the space shuttle and analyze it on the ground. The problem is there is a big delay. You’d like to be able to maintain iodine or silver [disinfectant] levels in real time with an onboard monitor,” says Marc Porter, a University of Utah professor of chemistry and chemical engineering.

Photo courtesy of Science Daily/NASA

The water–collected in sealed plastic bags–is passed over a half-inch-diameter, polymer, porous-membrane disk. Known as a “solid phase extraction membranes,” the disk captures either iodine or silver depending on the chemical treatment.

The disk is places against the German-made “reflectance spectrometer,” which reads the disks color in a matter of seconds. The device weighs about a pound and runs on AA batteries.

Photo courtesy of Science Daily/NASA

For the iodine test the disk is impregnated with PVP (polyvinylpyrrolidone)–a nontoxic chemical found in contact lens cleaning solution. For silver, the disk is imbued with DMABR which is short for 5-(dimethylaminobenzylidene)rhodanine.

Yellow indicates no silver and a fleshy-pink means it is present.

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