Wednesday, December 14, 2011

Latest Decon Technology from Japan: Coffee Filter

This one may actually work, if they can do it on a large scale. But I just can't visualize how.

A university researcher and his friend have come up with a cesium removal system from fallen leaves using a coffee filter.

From Mainichi Shinbun (12/15/2011):

落ち葉のセシウム 完全除去法を開発

A system to completely remove radioactive cesium from fallen leaves developed


Eisaku Katayama, 62-year-old researcher at the Engineering Department of Chiba University and former Professor of Tokyo University Medical Research Institute, and Isamu Kawakami, 63-year-old executive at a building firm in Shibukawa City in Gunma Prefecture have come up with a system to completely remove radioactive cesium from fallen leaves and weeds. They discovered that cesium binds to "plant opals" in leaves and stems of plants, and succeeded in removing cesium by removing the plant opals. Katayama is hopeful that their system "can be used in a variety of decontamination work".


The two focused on the characteristics of radioactive cesium which strongly binds with minerals whose main ingredient is silicon compound such as mica. Since plant opals contain the silicon compound, they hypothesized that the similar phenomenon may happen with the plant opals and conducted the experiment.


First, they put 570 grams of weeds from Minami Soma City, Fukushima Prefecture in a sealed container in mid November. After letting it rot until liquefied, they measured the density of radioactive cesium on December 10. The result was 28,924 becquerels/kg. They added water to this weed sludge, and filtered it using a coffee filter. They found that radioactive cesium was not detected from the filtered water. Upon close inspection of what remained on the coffee filter using a microscope, they identified numerous plant opals. They concluded that radioactive cesium had chemically bound with plant opals, and didn't go through the filter.


The dreg left on the filter was about one-tenths of the weeds. It contains concentrated level of radioactive cesium, but they want to develop a system to process a large amount of fallen leaves and weeds, as the system may be able to reduce the bulk of the leaves and weeds that takes up storage space.


A plant opal is a particle between several and 100 micrometer in diameter. It gets detached from fallen leaves and scatter. Katayama points out that it is necessary to store fallen leaves and weeds in an enclosed area and not in the open, and to wear masks in the contaminated areas with many plants.


Katayama and Kawakami became friends through their common hobby, astronomical observation. After being consulted by his friend in Fukushima Prefecture on decontamination, Kawakami did the research, with the help of Katayama. Katayama says, "It should have been written up and published as a research paper, but for the sake of the disaster-affected areas we'll put developing the practical application first."

If only radioactive cesium were the only nuclide that fell.


Anonymous said...

so right now they just dump the radioactive leaves in tokyo bay....this process will let them dump 'clean' non radioactive leaves and pure cesium into tokyo bay.....i dont see the difference.

Scott said...

Oak Ridge's 2011 deer harvest: 321 taken (3 too hot to take home)

"The third and final deer hunt of 2011 on the Department of Energy's Oak Ridge reservation was held over the weekend, and 80 deer were taken.

That brings the total for the three weekend hunts to 321 deer -- 177 bucks and 144 does, according to info provided by Oak Ridge National Laboratory. Of that total, three deer were retained at the checking station because they had too much radioactive contamination, the lab said."

This is a US nuclear facility built during WWII: the amount of contamination is not reported.

Atomfritz said...

My big respect to Katayama and Kawakami for their research, solution-finding and publishing the results as a "howto" do smart and effective decontamination by any non-expert without doing collateral damage instead to wait until the egghead community in their ivory towers has "peer reviewed" their findings some time next year when the leaves already rotted.

This is the kind of research actually needed BEFORE using nuclear power, to be ready to be applied in large scale when the need arises.

Too sad that this knowledge probably comes too late to make a noticeable difference in Japan's contamination. (As they incinerate the waste instead of burying them, the seem to desire to be contaminated anyway...)

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