Researchers create mercury-absorbent container linings for broken CFLs

Jun 27, 2008
Mercury Cloth
Brown University engineering students Love Sarin (left) and Brian Lee display a nanoselenium-enriched cloth that can capture mercury vapor from broken compact fluorescent lamps. Brown has applied for federal patents covering the invention and plans soon to begin commercial negotiations. Credit: John Abromowski, Brown University

With rising energy prices and greater concern over global warming, compact fluorescent lamps (CFLs) are having a successful run. Sales of the curlicue, energy-sipping bulbs, which previously had languished since they were introduced in the United States in 1979, reached nearly 300 million last year. Experts expect that figure to rise steeply by 2012, when a federal law requiring energy-efficient lighting goes into effect.

There's just one catch to this energy conservation story: Each CFL contains a small amount (3 to 5 milligrams) of mercury, a neurotoxin that can be released as vapor when a bulb is broken. The gas can pose a minor risk to certain groups, such as infants, small children and pregnant women. Mercury can escape from plastic bags containing discarded bulbs, which makes long-term storage, disposal or recycling tricky.

The obstacles have led to a debate over CFLs, illustrated by recent studies by the state of Maine and the nonprofit Mercury Policy Project over CFL use and safe levels of mercury in the bulbs. Now, a team of researchers at Brown University led by Robert Hurt, professor of engineering, and engineering student Natalie Johnson may have found a solution to the environmental conundrum.

The scientists, along with other Brown engineering students and Steven Hamburg, associate professor of environmental studies, have invented mercury-absorbent materials for commercial use. The team has created a prototype – a mercury-capturing lining attached to the inside of store-bought CFL packaging. The packaging can be placed over the area where a bulb has been broken to absorb the mercury vapor emanating from the spill, or it can capture the mercury of a bulb broken in the box.

The researchers also have created a specially designed lining for plastic bags that soaks up the mercury left over from the CFL shards that are thrown away.

The mercury-absorbent packaging and the lined plastic bags can be safely discarded and recycled, the researchers say, alleviating concerns about contamination or other unwanted environmental consequences.

"It's a complete management system to deal with a bulb broken in the home," says Hurt, director of Brown's Institute for Molecular and Nanoscale Innovation, which concentrates on the study and commercial application of nanotechnology.

Brown applied earlier this year for federal patents covering the mercury-absorption packaging and the absorbent material, and the university expects soon to begin discussions with companies on manufacturing the new technology.

"These patents represent how Brown University translates fundamental research into an application that can have an impact on society – in this case, a technology that could protect households from mercury exposure and that could also energize green business growth," says Clyde Briant, vice president for research at Brown.

The inspiration for the invention followed the discovery by Hurt, Johnson and fellow Brown researchers that a variant of a substance called nanoselenium – a form of selenium, a trace element used in diet supplements, among other products – absorbed virtually all the mercury emitted from a broken CFL. That finding appears this week in the online edition of Environmental Science & Technology. It is the first scientific paper that measures the timing and extent of mercury released from broken CFLs and that reveals the mercury-absorption potential of various nanomaterials, the researchers say.

The engineers tested 28 substances in all. Their experiments showed that one type of nanoselenium absorbed mercury vapor the most effectively. The selenium atoms bond with the mercury atoms to form mercury selenide (HgSe), a stable, benign nanoparticle compound, Hurt says.

The nanoselenium "just loves mercury," Hurt adds.

In controlled experiments, the scientists found that 99 percent of mercury vapor from a CFL broken in a sealed chamber was mopped up by nanoselenium in concentrations ranging from 1 to 5 milligrams.

The small amount needed to capture the mercury vapor bodes well for manufacturing mercury-absorbent cloths or lining at a low cost, Hurt says. The precise manufacturing costs will need to be determined by interested companies.

The National Institute of Environmental Health Sciences Superfund Basic Research Program funded the research.

The first prototype created by the Brown team is a three-layered cloth that is attached to the packaging or box containing the CFLs. The nanoselenium-coated layer would be sandwiched between the cardboard packaging and a cloth on the inside of the box containing the bulbs. The extra layers prevent people from coming into contact with the nanoselenium layer.

If a bulb breaks, the user simply undoes the packaging and lays it on the spot where the break occurred. The absorbent material is effective on different surfaces, including carpets and hardwood floors. "It works like a charm," Hurt says.

The second prototype incorporates the same layering and is fitted into a small, sealable plastic bag. The lining absorbs the mercury in the sealed bag, preventing it from escaping.

"More work is needed," Hurt says, "but this appears to be an inexpensive solution that can remove most of the safety concerns associated with CFL bulbs."


Source: Brown University

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RealScience
4 / 5 (4) Jun 27, 2008
If each CFL bulb sold came with this material in its package, then when replacing a bulb the old bulb could be thrown out in the new bulb's package, ensuring that when the bulb breaks its mercury would be absorbed.
(And CFLs do NOT last 10x longer than incandescents in normal use, so replacement is not infrequent.)
googleplex
4.8 / 5 (4) Jun 27, 2008
CFLs have a dirty secret.
The following should be on the packaging. You can find it on a Fed website
http://www.ct.gov...p?a=2708&q=378846&depNav_GID=1763

What To Do When A CFL Breaks

Proper use and handling of CFLs in the home should not result in any exposure to mercury. Handle the lamp carefully, installing and removing by the base, never the glass. If the lamp should break:

Open a window and leave the room for at least 15 minutes;
Do not use a vacuum cleaner to clean up the breakage;
Keep people and pets away from the breakage area until the cleanup is completed;
Wear disposable gloves and pick up the broken pieces;
Take a damp cloth and wipe and clean the area;
Pat the area with the sticky side of duct tape, packing tape or masking tape to pick up fine particles;
Place the broken pieces, cloth, disposable gloves and tape in a sealed bag.
Remove the bag and its contents from your home and dispose of in the outside household garbage.

For carpeted surfaces:

After the initial cleanup steps listed above are completed, if a rug is removable, take it outside, shake and air out for as long as practical;
If the carpet is not removed, after the initial cleanup steps listed above are completed, for the first time you vacuum, shut the door to the room or close off the area from as much of the rest of the house as possible and ventilate the room while vacuuming the area where the bulb was broken. Remove the vacuum bag when done cleaning the area, wipe the vacuum with a wet wipe, place the vacuum bag and wipe in a sealed plastic bag and place in the outside trash.
For the next several vacuuming events, the homeowner should consider ventilating the room during vacuuming.

googleplex
5 / 5 (3) Jun 27, 2008
With millions of mercury bulbs going into landfills we will see contamination of ground water.
I hope LED bulbs come down in price soon.
earls
5 / 5 (3) Jun 27, 2008
Hurray for saving the environment, eh google.

Agreed, this entire campaign of CFL "energy saving" bulbs has been a complete disaster since its inception.

But hey, at least it "feels good."

A very merry unbirthday to me...!
Glis
4.3 / 5 (3) Jun 27, 2008
Couldn't you just coat the outside of the bulb with a relatively clear resin so that they don't shatter?
googleplex
4 / 5 (2) Jun 27, 2008
Couldn't you just coat the outside of the bulb with a relatively clear resin so that they don't shatter?

Great idea. I think coating the inside might impact the ionization of the gas by contaminating the partial vacuum. Coating the outside of the bulb would be better. It could be done by dipping the bulb into a vat of resin. This would not interfere with the ionization on the inside. The trade off is reduced luminosity of the bulb and added cost. Another idea would be to put a transparent airbag around the bulb. Airbags are great shock absorbers. The problem here is keeping the airbag pressurized. Most balloons allow seepage of the gas. The envelope could be made of Tedlar which is transparent and doesn't leak (used in airships). Heck if they can keep a bag of chips and soda bottle pressurized I think it should be possible using cheap soda bottle plastic. A pressue seal would be needed between the plastic envelope and the stem of the glass bulb.
googleplex
3.8 / 5 (4) Jun 27, 2008
Dow! The major flaw in the idea of an unbreakable bulb is that it reduces sales! So we will never see this happen.
earls
4.5 / 5 (2) Jun 27, 2008
Just make them burn out faster! :)

Coating isn't a bad idea, but as mentioned, it would reduce the amount of light thereby requiring more energy.

Also, although they would excel in household scenarios, the coating may not survive improper disposal there by still leading to contamination.

It may in fact suggest the bulbs are now "safe" to "just throw away" leading to even greater nonchalant attitude towards the risk they pose.
gopher65
4 / 5 (2) Jun 27, 2008
Bah, earls, they already burn out too fast. They only last about as long as incandescents in reality anyway (with standard non-lab-controlled use), so making them burn out *even faster* would just be impractical.

I can't stand CFLs. As soon as LED bulbs start appearing in supermarkets, I'm there, even if they cost way more.
Soylent
4 / 5 (3) Jun 28, 2008
Bah, earls, they already burn out too fast. They only last about as long as incandescents in reality anyway.


Then stop buying no-name shit CFLs. I've never had a CFL "burn out", ever. They just get dimmer with time and after a few years(about 10-20 k hours) when they start to get too dim you replace them.
Soylent
3.3 / 5 (3) Jun 28, 2008
Hurray for saving the environment, eh google.

Agreed, this entire campaign of CFL "energy saving" bulbs has been a complete disaster since its inception.


Here's a fun fact, you coal burning yanks release more mercury over the life of a CFL if you use incandecents.
gopher65
4 / 5 (1) Jun 28, 2008
2 things Soylent: if an already dim bulb (due to the way they give off light, a CFL (or LED for that matter) will give off less usable light than an incandescent of similar lumenage rating) decreases in intensity, that's failure. Yes it is true that CFLs don't often undergo sudden catastrophic failure like incandescents do, but once they start to decrease in brightness, they are ruined and unusable in standard applications.

Second, most of the power around here is provided by either hydro or natural gas, with a proposed nuclear plant in the future. So there are no mercury emissions happening here. But yeah, if you use coal power, they you should do everything you can to decrease power consumption. Coal is truly disgusting stuff 0_0.

However. Coal plants don't get throttled. They burn at full steam all the time. So the only way a CFL actually causes less coal to be burned is if it stops another coal plant from being built. I have another solution to that one that doesn't involve using poison bulbs: stop the unnecessary construction of coal power plants. In most areas it is possible to construct something other than a coal plant. If it is, do so. Only build those nasty, dirty, dangerous coal plants when there is no other choice.
gopher65
4 / 5 (1) Jun 28, 2008
As another little fact: you know those graphs that you see about CFLs containing less mercury than an incandescent bulb would create if it were using coal power? Those graphs assume that 100% of the energy going to both the CFL and the incandescent is provided by coal. Uhhhh... that isn't the case. You can draw energy from many different plants because of the nature of the grid, and while some might be coal, others won't be (of course inefficiency increases dramatically as distance increases).

In reality only 25% of the world's energy needs come from coal, and that includes the ginormous number of coal plants in places like China. So take that graph you always see and divide the incandescents' mercury output by 4. Reality looks a little bit different than the spin these companies are putting on their product, doesn't it?

Oh, I forgot to say this in my pervious post about this stuff: you're right about low quality CFLs. They definately "burn out" (dim to uselessness) faster than brandname ones. My most recent bulb is a 14 dollar bulb. Ouch, heh. 14 bucks for one bulb. LEDs can't be much more than that, even today:P.
Ragtime
4 / 5 (2) Jun 28, 2008
Finely dispersed selenium is toxic as well and in presence of moisture it oxidizes to selenium oxides of unpleaseant garlic odor rapidly.
Soylent
3.7 / 5 (3) Jun 29, 2008
Yes it is true that CFLs don't often undergo sudden catastrophic failure like incandescents do, but once they start to decrease in brightness, they are ruined and unusable in standard applications.


That's not burning out; that's a slow and predictable loss of luminance and they clearly fulfill their rated life at acceptable output.

Coal plants don't get throttled. They burn at full steam all the time. So the only way a CFL actually causes less coal to be burned is if it stops another coal plant from being built.


Electric power consumption is still heading upwards and looks set to increase faster now that oil is getting uncomfortably expensive(e.g. substitute for heating oil with heat pumps).

Under a climate of increasing electric power use it will be difficult to decommission the dirtiest, grandfathered coal plants which are far outside current regulations. If the power is really needed people are a lot less reticent to allow non-sequestering new coal-fired generation.

Coal power is still the cheapest source as long as it gets a license to kill(about 20k people from COPD and lung cancer on average 14 years in advance according to the EPA) and a license to pollute; call me a cynic, but I don't think this is about to change even if nuclear is only slighty more expensive and takes good care of its waste.
Soylent
3.5 / 5 (2) Jun 29, 2008
As another little fact: you know those graphs that you see about CFLs containing less mercury than an incandescent bulb would create if it were using coal power? Those graphs assume that 100% of the energy going to both the CFL and the incandescent is provided by coal.


That may as well be, but it is still true at the 50% coal mix as used in the US with decent CFLs; and this is before you account for the fact that much of the mercury goes into the land-fills instead of being dispersed into the air(which I believe is a modest improvement) and before you count cadmium, coal particulates and other nastiness.

In reality only 25% of the world's energy needs come from coal, and that includes the ginormous number of coal plants in places like China.


That's not electric power generation, that's all use including vehicles, which don't use coal at all, and process heat, which mostly uses natural gas.

Coal-fired generation accounted for over 40% of electricity generation world wide in 2004 and I believe it has increased since, along with natural gas turbines.

LEDs can't be much more than that, even today:P.


Where can I pick up LEDs with a 5800 K colour temperature to replace my (not compact) flourescents? I can't stand that awful yellow crap.
gopher65
5 / 5 (3) Jun 29, 2008
Yarr. Coal power plants do kill a lot of people:(. They also produce more radioactive waste per unit of energy generated than any nuclear plant around:(. And that's not including all the non-radioactive toxic waste that they just freaking dump into lakes and rivers.

I think if people knew just how bad coal *really* was in comparison to nuclear, there wouldn't be a coal plant around. Nuclear just has an unfairly bad rep unfortunately.
_________________________________

I don't know if any 5800K LEDs exist yet. Residential LEDs just started coming out. It will be a few years before they're decent I'd imagine. The closest thing to a "warm" white LED that I've seen was a 3050K lamp, which had an equivalent brightness to a standard 20watt halogen bulb.

Quick question: how do I quote on this message board?
Egnite
4.5 / 5 (2) Jul 01, 2008
[.q.] quote [./.q.]

without the dots ofc
:-D
DGBEACH
4.3 / 5 (3) Jul 01, 2008
These guys are getting pretty close gopher
http://www.mouser...nductor/
gopher65
3.5 / 5 (2) Jul 01, 2008
Thanks guys:).
googleplex
5 / 5 (1) Jul 01, 2008
Yarr. Coal power plants do kill a lot of people:(. They also produce more radioactive waste per unit of energy generated than any nuclear plant around:(. And that's not including all the non-radioactive toxic waste that they just freaking dump into lakes and rivers.

I think if people knew just how bad coal *really* was in comparison to nuclear, there wouldn't be a coal plant around. Nuclear just has an unfairly bad rep unfortunately.

Good post. I have been hoping that more people become aware aware of this. Why-o-why don't they just put a scrubber on the stack! Coal would be a wonderful source of fuel if only then put a filter on it. The scrubber could operate like a refinery yielding multiple by products.
googleplex
not rated yet Jul 01, 2008
CFLs reduce mercury out of the stack but increase in our own homes.