Chinese team develop fuel cell that can clean water as it generates electricity

Aug 19, 2011 by Bob Yirka report
Chinese team develop fuel cell that can clean water as it generates electricity

(PhysOrg.com) -- Yanbiao Liu and his colleagues from Shanghai Jiao Tong University, have succeeded in building a device capable of both cleaning wastewater and producing electricity from it. Using light as an energy source the team created a photo-catalytic fuel cell that used a titanium dioxide nanotube-array anode and a cathode based on platinum. The light energy degrades the organic material found in the wastewater and in the process generates electrons which pass through the cathode converting it into electricity. The team has published its results on Water Science & Technology.

Liu notes in the paper, that wastewater (the stuff that goes down the toilet when flushed) or sewage, as it’s more commonly known in other countries, is a great source of environmental pollution and at the same time, is a truly important and often overlooked source of energy, which, unfortunately generally is not collected and used. It’s also an expensive by-product of human existence. Every day billions of people contribute to the ever growing problem of what to do with all the human waste that is created.

In addition to , wastewater often contains other materials that need to be removed in order to reuse the water for other purposes. In their lab the team tested their ’s ability to separate clear aromatics (perfumes), azo dyes, pharmaceuticals, personal care products and endocrine-disrupting compounds (birth control pill chemicals that wind up in urine) from wastewater samples and found they were able to separate them completely from the organic material thus producing clean water.

To allow the system to use visible and regular sunlight rather than UV, the team modified the electrodes with semiconductors (such as CdS) which means of course the system, if industrialized, could be used outside as an add-on perhaps to existing wastewater treatment plants.
So far the team hasn’t listed cost estimates for building an electrical/wastewater treatment facility with their new technology, but it’s not hard to see how useful such a plant would be in areas where sewage is sometimes not treated at all, but simply dumped into rivers or streams, or worse, in the streets. In addition to helping clean up such places, the people in those areas would benefit from the electricity that would be produced in the process.

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More information: A TiO2-nanotube-array-based photocatalytic fuel cell using refractory organic compounds as substrates for electricity generation, Chem. Commun., 2011, Advance Article, DOI: 10.1039/C1CC13388H

Abstract
A TiO2-nanotube-array-based photocatalytic fuel cell system was established for generation of electricity from various refractory organic compounds and simultaneous wastewater treatment. The present system can respond to visible light and produce obviously enhanced cell performance when a narrow band-gap semiconductor (i.e. Cu2O and CdS) was combined with TiO2 nanotubes.

via Royal Society of Chemistry

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User comments : 6

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RustyMustard
not rated yet Aug 19, 2011
Cool, how scalable will this technology be? I'm off-grid and would love to have a cell like this someday to feed black water into. I want a Poo-cell!
Eric_B
5 / 5 (1) Aug 19, 2011
It's a Poo-Er Cell, amn.
Jeddy_Mctedder
1 / 5 (3) Aug 19, 2011
funny ge just invested in an israeli company that developed technology for just this purpose.
Skepticus
Aug 19, 2011
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Nanobanano
1 / 5 (2) Aug 19, 2011
Anyway, there's not that much energy in human waste.

You only eat like 2,000 to 2,800 food calories per day, which is 8,400,000 to maybe 11,760,000 Joules.

Considering your body is at least a couple percent efficient, then the amount of energy you send down the toilet each day must be less than that per person.

This comes to probably no more than about 1/20th of a gallon of gasoline equivelant per person per day, not counting the generator is probably no more than 45% efficient.

If we treat all humans as adults, and if the entire world used this technology, the total amount of energy produced is then around 345 million gallon equivalents of gasoline per day.

This comes to around 3 billion barrel equivalents of oil per year.

Which only equals about 1/7th of the oil used world wide each year.

Turns out, oil only equals a little over 1/5th of total human energy consumption.

So if all of the earth had this tomorrow, it would make a 1/35th difference in energy use...
Jeddy_Mctedder
3.1 / 5 (7) Aug 19, 2011
your staetment is bogus. the point of this technology is that cities MUST run sanitation plants to deal with sewage treatement. there is NO choice. currently they use a lot of electricity. if you already have poo in one place, every joule you take out of it to run the plant ( which requires a lot of electricty) is a joule directly placed back into the grid. and if ALL sewage plants started using this technology, it would save a great deal of energy.

So if all of the earth had this tomorrow, it would make a 1/35th difference in energy use...
paulo
Aug 19, 2011
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Nanobanano
Aug 19, 2011
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paulo
Aug 19, 2011
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trekgeek1
Aug 19, 2011
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Skepticus
Aug 19, 2011
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mortoo
not rated yet Aug 20, 2011
Very interesting and looks neat. I am wondering what the products are. The text in the diagram is a little hard to read.

The third paragraph says it can separate aromatics etc from organic material to produce clean water. That doesn't make a lot of sense to me. Is water with organics in it clean? And where does the separation occur?
krwhite
Aug 20, 2011
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Shootist
Aug 21, 2011
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