Recently WUWT carried a story about “solar roads” which had a ridiculous premise with a big batch of “feel good” Eco-egineering that is technically and economically implausible. This idea for catalytic reduction of smog looks far more plausible and less expensive.
Students develop titanium dioxide roof tile coating that removes up to 97 percent of smog-causing nitrogen oxides
RIVERSIDE, Calif. (www.ucr.edu) — A team of University of California, Riverside’s Bourns College of Engineering students created a roof tile coating that when applied to an average-sized residential roof breaks down the same amount of smog-causing nitrogen oxides per year [produced by] as a car driven 11,000 miles.
They calculated 21 tons of nitrogen oxides would be eliminated daily if tiles on one million roofs were coated with their titanium dioxide mixture. They also calculated it would cost only about $5 for enough titanium dioxide to coat an average-sized residential roof.
That would have a significant impact in Southern California, where 500 tons of nitrogen oxides are emitted daily in the South Coast Air Quality Management District coverage area, which includes all of Orange County and the urban portions of Los Angeles, Riverside and San Bernardino counties.
Last month, the research by the UC Riverside team – Carlos Espinoza, Louis Lancaster, Chun-Yu “Jimmy” Liang, Kelly McCoy, Jessica Moncayo and Edwin Rodriguez – received an honorable mention award for phase two of an Environmental Protection Agency student design competition.
A UC Riverside student team who worked on the project last year received $15,000 as a phase one winner of EPA’s P3 (People, Prosperity and the Planet) competition. That team consisted of William Lichtenberg, Duc Nguyen, Calvin Cao, Vincent Chen and Espinoza (an undergraduate then who is now a graduate student at UC Riverside).
Both teams were advised by David Cocker, a professor of chemical and environmental engineering, and Kawai Tam, a lecturer at the Bourns College of Engineering.
Nitrogen oxides are formed when certain fuels are burned at high temperatures. Nitrogen oxides then react with volatile organic compounds in the presence of sunlight to create smog.
Currently, there are other roofing tiles on the market that help reduce pollution from nitrogen oxides. However, there is little data about claims that they reduce smog.
The students set out to change that. They coated two identical off-the-shelf clay tiles with different amounts of titanium dioxide, a common compound found in everything from paint to food to cosmetics. The tiles were then placed inside a miniature atmospheric chamber that the students built out of wood, Teflon and PVC piping.
The chamber was connected to a source of nitrogen oxides and a device that reads concentrations of nitrogen oxides. They used ultraviolet light to simulate sunlight, which activates the titanium dioxide and allows it to break down the nitrogen oxides.
They found the titanium dioxide coated tiles removed between 88 percent and 97 percent of the nitrogen oxides. They also found there wasn’t much of a difference in nitrogen oxide removal when different amounts of the coating were applied, despite one having about 12 times as much titanium dioxide coating. There wasn’t much of a difference because surface area, not the amount of coating, is the important factor.
The current team of students, all of whom are set to graduate in June, are hopeful a new team of students will continue with this project and test other variables.
For example, they want to see what happens when they add their titanium dioxide to exterior paint. They are also considering looking at applying the coating to concrete, walls or dividers along freeways. Other questions include how long the coating will last when applied and what impact changing the color of coating, which is currently white, would have.
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Planting trees and painting white have little effect on global climate. 71% of earth’s surface is ocean. Of the remaining 29% land, 97% is deserts, forests and agricultural land. You can only paint on the 3% urban land. You can plant trees on forests and agricultural land but forests already have trees and you cannot just convert wheat fields to tree plantations. Limited area to plant trees.
I heard ideas like planting algae and floating white ping pong balls in oceans. But too expensive and will harm ocean ecosystem.
The irrelevant statistic award of the day goes to:
“They also calculated it would cost only about $5 for enough titanium dioxide to coat an average-sized residential roof.”
If my memory serves me correctly; Barium Oxide used to be the standard bright white high reflectance paint, until TiO2 came along. And who knew that unoxidized Titanium, simply explodes. They should tell our aircraft designers to stop using it. And who would want to take the risk of having an explosive Titanium bolt holding one’s hips together. I knew Titanium was somewhat difficult to machine, but didn’t realize it simply explodes in the lathe chuck.
I’ll have to go and check all my fly rods to see that all the Titanium line guides are in good shape, and not about to explode. But most of them are either black Titanium Carbide coated, or gold Titanium Nitride, when visibility doesn’t matter.
The bright white reflective plastic cavities used in larger seven segment LED numeric digital displays are all Titanium dioxide filled. But in that case, they blow right past the infamous 97% consensus barrier, and achieve a minimum of 98% diffuse reflectance for most visible wavelengths.
Was this a 4-H club paper, that arose out of how to paint pig sties, so they don’t look grubby ??
https://www.google.fr/search?q=marque+de+vêtements+en+chanvre&tbm=isch&tbo=u&source=univ&sa=X&ei=O9iTU7CRA4ij
new clothes – in “chanvre” (hemp)