Hi, Andrew - It would be great if someone like Mike MacCracken could comment on some of the chemistry in your posting - in that it seems to me confusing, and, I suspect, somewhat confused. Could you, Andrew, show the reactions that you're thinking of, so I could understand better? You say that - "If the coating acts on NOx and or the OH radical, it may even be counter productive!" and also say that "OH recycles NOx." Also you write: "NOx production uses free raw materials and is well mixed through the atmosphere." My understanding goes against pretty much all of this, if I am understanding you correctly.
NOx certainly gets involved in reactions that lead to increased RF. But generally NOx is considered climate neutral, I believe, because if you take a NOx-centric view, you see it taking part in various reactions that have both positive and negative indirect forcings, and that roughly cancel each other out. If you look at, say, the NOx-methane interactions, where NOx laden air produces more O3 in CH4 oxidation, then that added forcing is generally counted for as part of CH4's indirect forcing, not counted for as a "indirect forcing" for NOx. That makes more sense, I suppose, in that the methane is fundamental to creating the greenhouse effect anyhow, is one of the most primary biomolecules on the planet, etc. NOx, I believe, always demands considerable energy to create (what did you mean by OH recycles it?), since it demands the splitting of the N2 triple bond, so the NOx in our air is almost all anthropogenic and comes from internal combustion engines and such. There's very little of it in unpolluted air, except from lightning and other high energy things. OH is the primary oxidant of the atmosphere, and, though it can fluctuate a good deal, the total budget is assumed to be surprisingly stable, given all the human assaults on the atmosphere. Thus, if you look at more recent RF pie charts (Shindell at GISS has done lots of work on indirect RFs), NOx is not there at all, but VOCs and CO obviously are, and are quite important - indeed, they have added twice the RF of N2O, which, unlike NOx, IS a fundamental part of non-anthropogenic chemistry and of the planet's GH effect. So, the way I see it, then, if you can catalyze more OH production directly from the sun's energy, either from singlet O or from splitting an O3 (not by creating new O3!), that's a very good thing. But, on the other hand, you want to get rid of NOx, not increase it. NOx will increase the CH4 indirect forcing, and while it will create some OH - and OH gets "reincarnated" in the process of the methane oxidation chain of reactions - that's your BAD OH, in that it's leading to the creation of more O3, I think. In terms of TiO2 being practical or not, obviously if white roofing is practical, then the photocatalytic surface is, too. They both use TiO2. And white roofing is the most "practical" of all geoengineering, in that no one is opposed to it. The surface would be much cheaper than the paint. Even solar energy might use TiO2 as well. Of course, if ALL of that happened, there'd be a big crunch on TiO2 and the need to search for new sources. The most confused part of your post seemed to me: "Tio2 works well on poorly mixed pollutants with a high contact area, none of which applies to methane." But that's the whole point: the NOx discussion is essentially a red herring in terms of climate impacts, but these "poorly mixed pollutants" - the VOCS and CO - are almost 7% of +RF since industrialization - and their RF is really all methane-related: It's an indirect forcing coming from the OH budget deficit they cause, in turn slowing the methane sink. But, you see, the TiO2 makes new OH from singlet O + H2O, or O3, and it acts on those "poorly mixed pollutants" like VOCs and CO effectively, as you agree - which are in copious quantities all around human surfaces. This should then cut down on that 7% of RF by reducing a major indirect forcing, and thus speeding up methane's oxidation. Cheers, Nathan On Thu, Jul 28, 2011 at 3:22 PM, Andrew Lockley <[email protected]>wrote: > This proposed method of methane remediation is similar to the existing > sink, as although OH radical production isn't strictly catalytic, it does > recycle NOx. Whether the chemistry works or not is something I can't comment > on. > > However, I don't think that TiO2 is likely to be practical. Although it is > leveraged (as it uses the suns energy), it is limited in the contact surface > area, potential area of application and the availability and possibly the > cost of raw materials. In contrast NOx production uses free raw materials > and is well mixed through the atmosphere. Tio2 works well on poorly mixed > pollutants with a high contact area, none of which applies to methane. > > I'm also not sure of the proposed TiO2 chemistry. If the coating acts on > NOx and or the OH radical, it may even be counter productive! > > I'd be prepared to be proved wrong on all of the above :-) > > A > On 28 Jul 2011 18:50, "Nathan Currier" <[email protected]> wrote: > > Hi Andrew, Sam, Oliver - > > > > I heartily agree, & think that this is potentially one of the > > "sleepers" of the geoengineering world - > > it is also unique in that it is neither CDR nor SRM & would probably > > be quite safe & thus easily enacted. > > > > I would doubt that you're going after it the right way, though, Sam, > > in that the kinds of things > > you have been thinking about always demand passing air - which is way > > too > > energy-intensive. And Oliver, clearly one doesn't want to be > > intentionally making > > any new GHGs while trying to fix the GHG problem, unless it's making > > something pretty damn > > destructive of GHGs later on!..... > > > > Andrew, I'm not sure what you meant by "leveraging existing > > processes", > > but I had an idea in this general line several years ago, and actually > > first learned of this > > group when I saw Mike mentioning to Ken something about it...... > > > > In a sense, it is like using the band gap energy used in solar cells, > > but the energy makes > > hydroxyl instead.....of course, that's already a well developed idea, > > and it all started > > in Japan - it's sometimes called the "Fujishima effect" after Akira > > Fujishima who started it. > > It's been used in various forms of environmental remediation for quite > > some time now. > > > > It's all about exploiting the unique photocatalytic properties of > > TiO2. At this point there has now been lots > > of research in Japan (and much of it not translated, I've been told), > > and there are even commercial products > > called "environmental nano-coatings" and so on. There's a leading TiO2 > > expert at UVA (John Yates) who I approached about all this, > > who told me once of visiting Fujishima, and being taken to a place in > > Tokyo where a whole block of large city buildings > > have been covered in a TiO2 coating, and studies have shown the NOx, > > O3, & CO, VOCs and other reactive species > > are all greatly reduced around there from the surrounding air - with > > huge % changes, 30% and more. > > > > So, my simple idea had been this: if one thinks of the atmospheric OH > > sink as a drain in which more reactive species selectively > > go down more easily, raising OH anywhere and letting it act on VOCs > > etc, should, globally considered, accelerate > > the methane sink thus lowering the CH4 forcing (and that's behind the > > "indirect GWP" concept of such species). Since > > methane is a LLGHG, Sam, it's a waste to spend energy pushing air > > around - methane is already everywhere. > > > > Therefore, an entirely passive approach could be to add a photo- > > catalytic coating on top of white surfacing. It's a highly > > synergistic concept, since the TiO2's unique hydrophobic/hydrophilic > > qualities also make it an albedo booster (keeping white things > > whiter), by being a self-cleanser of surfaces (TiO2 is used to keep > > windows cleaner, for ex.) It would be MUCH cheaper than the white > > paint used for the surfacing, by at least a few orders of magnitude. > > My guess would be this approach could greatly boost the climate impact > > of white surfacing projects, and I haven't seen studies exploring this > > at all yet, although grad students at UVA told me it probably has > > already been studied in Japan, and I never had good enough data to > > even make my own rough calculations of what it might yield. > > > > Now, then, I mentioned that it's kind of like solar energy, in a > > sense. Do you know of Graetzel, who started the Graetzel cell? > > That's a solar cell that's TiO2 based (and could be the "Next Big > > Thing" for the world, if it turns out well.....i.e., the solar slurry > > idea). > > I had once come across a very early paper of his, and think it could > > lead to something in this area you are all looking at: > > he was studying the capacity to degrade methane in ambient conditions, > > & so was studying TiO2 with co-catalysts. He wrote a paper > > on a molybdenum doped TiO2 that seemed to have a good action on > > methane at ambient temperature. So this would be more like pulling the > > methane right down the drain, rather than waiting for the lowered VOCs > > etc to help the methane go down it. It would demand a LOT of work to > > both explore various co-catalysts and see what's the best for directly > > attacking methane, and then to determine which route would be better > > to pursue - such a targeted catalyst, or a simpler "OH maker" that > > targets nothing at all, but helps "open the drain." > > > > As far as that last goes, another thing: John Yates (the one at UVA), > > while he right away told me that he "doesn't invent things," and thus > > had no interest in getting involved directly in my pursuit, did > > mention a curious thing to me, in a presentation he arranged for me by > > some of his grad students. The unique properties of TiO2 come from > > defects in the crystal lattice structure of the molecule. He's the > > world's leading expert of this, a theoretical chemist who has spent > > his life perfecting his own construction (a specially dedicated kind > > of SEM, I think) to look deep inside the TiO2 molecule. One thing he > > said to me stuck in my mind: it might not be hard, he said, to use > > nano tech to expand the defect of the O atom, and thus get more OH > > made through its band gap activation. So, this could make a more > > productive molecule - either for making solar energy, or, I suppose, > > for taking junk out of the air and lowering its RF. > > > > cheers, > > > > Nathan > > > > ps - re arctic methane - since this is mild approach, I doubt it would > > be a big part of dealing with any emergency there, but if it were, it > > could involve adding such a coating on top of the kind of recycled > > plastic faux ice-floe idea that I've mentioned before in this > > group.... > > > > > > > > > > > > > > > > > > > > I got another UVA chemistry faculty (Lehmann) who has developed > > perhaps the most sensitive way of reading methane, with dual lasers, > > interested in helping me run some simple experiments. > > > > > > > > > > > > > > On Jul 26, 7:32 am, Andrew Lockley <[email protected]> wrote: > >> Creating OH radical is best done by leveraging existing processes. > >> The radical is too short-lived to be effectively distributed when > >> produced industrially, and energy costs are also too high. > >> > >> The NOx recycling reaction series was chosen by L Zhou et al in their > >> recent paper, as (in dry air) NOx is persistent and recycles. > >> > >> For the paper, seehttp:// > www.atm.helsinki.fi/FAAR/reportseries/rs-109/abstracts/Luxi%20... > >> > >> Biological processes are able to indirectly create NOx by nitrogen > >> fixation using symbiotic bacteria in root nodules. The plants can > >> then be burned to liberate NOx into the atmosphere. The Lupin is one > >> potential candidate, but other N2 fixers such as clover may also work. > >> This could additionally perhaps be used as a source of biochar. The > >> slight complexity is that NOx rains out in wet air, but the plants > >> need to be grown in wet soil. Haul costs are likely to be a > >> significant issue, therefore. > >> > >> One slightly 'far out' approach is to press ahead with the attempts to > >> make non-legumes capable of fixing N2 through GM. This would > >> revolutionize global agriculture, as well as giving a feedstock for > >> geoengineering - as the N2 fixation process is the chemical > >> underpinning of protein creation in crops. This isn't fanciful, and > >> lots of work is already being done. > >> > >> An alternative technique with a much more limited scope of application > >> is the addition of Br2 to create Br radical. This would need to be > >> done in clean, damp air overlying the oceans. There is an existing > >> 'hole' in the global OH shield east of Papua New Guinea, where this > >> technique could be applied.http://eprints.ifm-geomar.de/10069/ It is > >> one of the authors of this paper who suggested the Br technique to me. > >> > >> The downsides of creating NOx, as Zhou et al note, is that the both > >> NOx itself, and the trop O3, are both toxic and also GHGs in their own > >> right. It's not a pleasant solution to have to be considering. > >> > >> Readers should note the Kyoto controls on NOx, which have a beneficial > >> effect by potentially reducing forcing, but a negative indirect effect > >> by reducing OH radical production, which will become more significant > >> in a low OH, high CH4 atmos. However, it should also be noted that > >> locally high NOx concentrations are associated with different > >> chemistry which does not lead to the production of OH and the > >> consequential breakdown of methane. Therefore, industrial OH > >> controls, particularly in smoggy cities, are generally beneficial, > >> whereas in rural areas those same controls may have a positive RF > >> outcome. > >> > >> This is a very interesting field, and one that more assistance and > >> input is welcomed in. > >> > >> A > >> > >> On 26 July 2011 10:54, Sam Carana <[email protected]> wrote: > >> > >> > >> > >> > Oliver Tickell wrote: > >> >> Another approach would be to enhance HO hydroxyl in the atmosphere - > the > >> >> main destroyer of methane. I have no idea how to set about doing > this. It > >> >> could be helpful to reduce emissions that utilise existing hydroxyl, > such as > >> >> miscellaneous hydrocarbons. But the chemistry is complex and it is > hard to > >> >> strictly follow through any intervention to its end results! > >> > >> > There are a number of methods that seek to reduce methane whilst still > >> > in the water (microbes, bubbles, covering the water surface with white > >> > plastic to capture the methane, etc). > >> > >> > One problem is that, in many places (including in ESAS), waters are > >> > shallow and there's little time for microbes to do their work, > >> > especially when hydrates suddenly start releasing huge amounts of > >> > methane. > >> > >> > Therefore, it's crucial to also look at hydroxyl and I advocate two > >> > types of feebates to help reduce emissions that compete for hydroxyl: > >> > 1. Energy feebates (seeking to reduce emissions from power plants and > >> > help electrify transport); and > >> > 2. Fees on livestock products to fund biochar, which will reduce > >> > methane, while encouraging pyrolysis and thus also reduce BC, VOC and > >> > the like. > >> >http://knol.google.com/k/sam-carana/the-way-back-to-280-ppm/7y50rvz99. > .. > >> > >> > As to enhancing hydroxyl in the arctic, here are some suggestions: > >> > >> > - Tri-Air Developments has developed a technology that combines UV > >> > light with extremely low levels of ozone and mixes it with volatile > >> > hydrocarbons, to produce hydroxyls. This technology is used in Cirrus3 > >> > devices that emit hydroxyls in rooms of less than 25m3 up to rooms in > >> > excess of 500m3 (image below). Perhaps such technology could be used > >> > at large scale in the Arctic to combat the methane menace. > >> > >> > - Another method may be to use UV light for photolysis of hydrogen > peroxide. > >> > >> > - Using UV light to break down methane in the Arctic could possibly be > >> > achieved by model airplanes, equipped with LiPo batteries and with > >> > solar thin film mounted both on top of and underneath the wings. > >> > Numerous such planes could navigate the Arctic by autopilot in summer, > >> > when there are high concentrations of hydrogen peroxide and when the > >> > sun shines 24-hours a day. Flying figure-8 patterns with the wings > >> > under an angle could optimize capture of sunlight, keeping the planes > >> > in the air, while using surplus energy to power UV lights. At the end > >> > of summer, the planes could return home for a check-up and possible > >> > upgrade of the technology, to be launched again early summer the next > >> > year. > >> > >> >http://knol.google.com/k/the-threat-of-methane-release-from-permafros. > .. > >> > >> > Cheers! > >> > Sam Carana > >> > >> > On Tue, Jul 26, 2011 at 1:44 PM, John Nissen <[email protected]> > wrote: > >> > >> >> Thanks Oliver. > >> > >> >> I'm posting your comments to the geoengineering group with the > questions you > >> >> raise: > >> > >> >> 1. Could the CDM be used to fund, or help fund, our pilot project to > trial > >> >> various techniques for tackling the Arctic methane problem? Could it > >> >> subsequently fund deployment of selected techniques? > >> > >> >> 2. Is there any way to enhance HO hydroxyl in the atmosphere? > >> > >> >> Cheers, > >> > >> >> John > >> > >> >> --- > >> > >> >> On 25/07/2011 17:52, Oliver Tickell wrote: > >> > >> >> Certainly it makes sense to do something about large, concentrated > methane > >> >> emissions where it is realistic to capture the gas and burn it off, > or use > >> >> it for heat / power. > >> > >> >> Does the CDM currently provide credits for methane projects of this > type? I > >> >> believe it does for methane from pig farms etc so there is no obvious > reason > >> >> why it should not. > >> > >> >> Another approach would be to enhance HO hydroxyl in the atmosphere - > the > >> >> main destroyer of methane. I have no idea how to set about doing > this. It > >> >> could be helpful to reduce emissions that utilise existing hydroxyl, > such as > >> >> miscellaneous hydrocarbons. But the chemistry is complex and it is > hard to > >> >> strictly follow through any intervention to its end results! > >> > >> >> Oliver. > >> > >> >> -- > >> >> Oliver Tickell > >> > >> >> On 25/07/2011 15:09, Veli Albert Kallio wrote: > >> > >> >> I think definitely that we can prevent on-shore methane explosions, > and > >> >> saturated methane laden water pockets that are approaching nucleating > point. > >> > >> >> There are 3 types of methane leaking: > >> > >> >> 1) generic leaking of methane from melting permafrost over large > areas that > >> >> provide widespread methane haze > >> >> 2) spot type ongoing methane leaking from permaforst or onshore gas > fields > >> >> that are losing their subterranean gas compression due to ruptures. > >> >> 3) explosive methane eruptions (methane clatrates, Lake Cheko's > conical > >> >> basin gas field failure in Tunguska 1908 as river fell into gas field > and > >> >> drove methane out). > >> > >> >> No. 1 you cannot control. No. 2 depends on how big and focused the > leaking > >> >> is, there are vast bubbling spots, in Azerbaijan there are flaming > mountains > >> >> where gas comes out of rocks. These you can control. No. 3 can be > controlled > >> >> by method of Professor Michel Halbwachs. Often methane can be spotted > as a > >> >> very focused leak on sea floor which might be possible to cap. So, I > think > >> >> the idea is valid in certain cases, in other cases it may not be > workable. > >> > >> >> ________________________________ > >> >> Date: Mon, 25 Jul 2011 11:28:12 +0100 > >> >> From: [email protected] > >> >> Subject: Re: Arctic methane workshop, London, 15-16th October > CONFIRMED > >> >> To: [email protected] > >> > >> >> John, I think you are on a hiding to nothing trying to trap or > destroy the > >> >> methane. > >> > >> >> The reason is simple - the emissions are spread over such a vast area > of > >> >> many millions of sq.km. Even to trap and destroy the methane > emissions from > >> >> 1sq.km would be a fantastically difficult and expensive task. > >> > >> >> So you can simplify things by just ruling this one out at the start! > >> > >> >> Oliver. > >> > >> >> -- > >> >> Oliver Tickell > >> > >> >> On 22/07/2011 18:29, John Nissen wrote: > >> > >> >> Dear all, > >> > >> >> In case you were not aware, the workshop, which was to have been > 3-4th > >> >> September, is now going to be on 15-16th October. Here is the > background > >> >> and purpose of the workshop... > >> > >> >> A group of scientists and engineers (including myself) is deeply > concerned > >> >> about the potential of methane from thawing permafrost in the Arctic > to > >> >> cause irreversible, catastrophic and unsurvivable global warming. > Major > >> >> factors are the unexpectedly rapid retreat of sea ice [1] and the > >> >> unexpectedly large quantities of carbon which might be emitted as > methane > >> >> [2]. In June 2010 we wrote an open letter to Obama's scientific > adviser, Dr > >> >> John Holdren, suggesting action was urgently needed to address the > methane > >> >> issue [3]. Some sea ice experts, including Professor Peter Wadhams > in our > >> >> group, now reckon the Arctic Ocean will very likely become seasonably > ice > >> >> free this decade if there is no action to cool the Arctic. > >> > >> >> Recently Peter Wadhams has drawn my attention to work of Natalia > Shakhova > >> >> with Igor Semiletov on East Siberian Arctic Shelf (ESAS) - > particularly > >> >> concerning the present large emissions of methane and the possibility > of > >> >> release of much larger quantities "at any time". So we have been > wondering > >> >> whether anything can be done quickly to reduce this methane threat. > We > >> >> have been discussing possible action, and plan > >> > >> ... > >> > >> read more ยป > > > > -- > > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > > To post to this group, send email to [email protected]. > > To unsubscribe from this group, send email to > [email protected]. > > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > > > -- Nathan Currier 108 Ellwood Street, #43 New York, NY 10040 401-954-3402 www.nathankindcurrier.com -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
