The Year of Elements, and a Crisis

This is the International Year of the Periodic Table, and since it is almost over, one can debate how useful it was. I wonder how many readers were aware of this, and how many really understand what the periodic table means. Basically, it is a means of ordering elements with respect to their atomic number in a way that allows you to make predictions of properties. Atomic number counts how many protons and electrons a neutral atom has. The number of electrons and the way they are arranged determines the atom’s chemical properties, and thanks to quantum mechanics, these properties repeat according to a given pattern. So, if it were that obvious, why did it take so long to discover it?

There are two basic reasons. The first is it took a long time to discover what were elements. John Dalton, who put the concept of atoms on a sound footing, made a list that contained twenty-one, and some of those, like potash, were not elements, although they did contain atoms that were different from the others, and he inferred there was a new element present. The problem is, some elements are difficult to isolate from the molecules they are in so Dalton, unable to break them down, but seeing from their effect on flames knew they were different, labelled them as elements. The second problem is although the electron configurations appear to have common features, and there are repeats in behaviour, they are not exact repeats and sometimes some quite small differences in electron behaviour makes very significant differences to chemical properties. The most obvious example is the very common elements carbon and silicon. Both form dioxides of formula XO2. Carbon dioxide is a gas; you see silicon dioxide as quartz. (Extreme high-pressure forces CO2 to form a quartz structure, though, so the similarity does emerge when forced.) Both are extremely stable, and silicon does not readily form a monoxide, while carbon monoxide has an anomalous electronic structure. At the other end of the “family”, lead does not behave particularly like carbon or silicon, and while it forms a dioxide, this is not at all colourless like the others. The main oxide of lead is the monoxide, and this instability is used to make the anode work in lead acid batteries.

The reason I have gone on like this is to explain that while elements have periodic properties, these are only indicative of the potential, and in detail each element is unique in many ways. If you number them on the way down the column, there may be significant changes depending on whether the number is odd or even that are superimposed on a general change. As an example: copper, silver, gold. Thus copper and gold are coloured; silver is not. The properties of silicon are wildly different from those of carbon; there is an equally dramatic change in properties from germanium to tin. What this means is that it is very difficult to find a substitute material for an element that is used for a very specific property. Further, the amounts of given elements on the planet depend partly on how the planet accreted, thus we do not have much helium or neon, despite these being extremely common elements in the Universe as a whole, and partly on the fact that nucleosynthesis gives variable yields for different elements. The heavier elements in a periodic column are generally formed in lower amounts, while elements with a greater number of stable isotopes, or particularly stable isotopes, tend to be made in greater amounts. On the other hand, their general availability tends to depend on what routes there are for their isolation during geochemical processing. Some elements such as lead form a very insoluble sulphide and that separates from the rock during geothermal processing, but others are much more resistant and remain distributed throughout the rock in highly dilute forms, so even though they are there, they are not available in concentrated forms. The problem arises when we need some of these more difficult to obtain elements, yet they have specific uses. Thus a typical mobile phone contains more than thirty different elements

The Royal Society of Chemistry has found that at least six elements used in mobile phones are going out be mined out in at least 100 years. These have other uses as well. Gallium is used in microchips, but also in LEDs and solar panels. Arsenic is also used in microchips, but also used in wood preservation and, believe it or not, poultry feed. Silver is used in microelectrical components, but also in photochromic lenses, antibacterial clothing, mirrors, and other uses. Indium is used on touchscreens and microchips, but also in solar panels and specialist ball bearings. Yttrium is used for screen colours and backlighting, but also used for white LED lights, camera lenses, and anticancer drugs, e.g. against liver cancer. Finally, there is tantalum, used for surgical implants, turbine blades, hearing aids, pacemakers, and nosescaps for supersonic aircraft. Thus mobile phones will put a lot of stress on other manufacturing. To add to the problems, cell phones tend to have a life averaging two years. (There is the odd dinosaur like me who keeps using them until technology makes it difficult to keep doing it. I am on my third mobile phone.)A couple of other facts. 23% of UK households have an unused mobile phone. While in the UK, 52% of 16 – 24 year olds have TEN or more electronic devices in their home. The RSC estimates that in the UK there are as many as 40 million old and unused such devices in people’s homes. I have no doubt that many other countries, including the US, have the same problem. So, is the obvious answer we should promote recycling? There are recycling schemes around the world, but it is not clear what is being done with what is collected. Recovering the above elements from such a mixture is anything but easy. I suspect that the recyclers go for the gold and one or two other materials, and then discard the rest. I hope I am wrong, but from the chemical point of view, getting such small mounts of so many different elements from such a mix is anything but easy. Different elements tend to be in different parts of the phone, so the phones can be dismantled and the parts chemically processed separately but this is labour intensive. They can be melted down and separated chemically, but that is a very complicated process. No matter how you do it, the recovered elements will be very expensive. My guess is most are still not recovered. All we can hope is they are discarded somewhere where they will lie inertly until they can be used economically.

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An Imminent Water Crisis?

We have all heard the line “Water water everywhere, nor any drop to drink.” Well, soon we may have to rethink “everywhere”. There was a tolerably scary future hinted at by a recent letter in Nature (de Graaf, et al, 574: 90). It points out that groundwater is critically important for food production and currently pumping exceeds recharge from rainfall and rivers in many parts of the world. Further, when groundwater levels drop, discharges to streams declines or even stops completely, which reduces river flow, with potentially devastating effects on aquatic life. These authors claim that about 70% of pumped groundwater is used to sustain irrigation and hence food production. There are other problems, such as ground subsidence. If you take away matter from below you, then what you have between you and where you took it must eventually lower, but with land it does not have to do so evenly. Coastal flooding in some US cities is not really exacerbated by climate change to anywhere near the extent it is by the ground lowering due to groundwater removal. 

If the streams to rivers are not recharged, there is a slow desiccation of the nearby land. The billions of tonnes of water locked in soils and bedrock and various aquifers is the biggest single source of fresh water on the planet. Life essentially depends on this resource yet we are unthinkingly depleting it. Most people know that people in dry lands will experience worse conditions due to rising temperatures. What most don’t realise is the inability to properly recharge the aquifers they depend on will lead to even worse problems, not the least through the requirement for more water as temperatures increase.

The paper also provided maps that outline the size of the crisis, but in my opinion also shows a problem inherent in such studies: there was a map that showed the head decline that might lead to a crisis, which really indicates how much groundwater there is. Included is two-thirds of the South Island of New Zealand. Now for parts of Canterbury that may well be the case, but it also includes the West Coast of the South Island. The geology there may well indicate there is not much groundwater, and in fairness I have never heard of anyone drilling wells there, but there is not exactly a water shortage there because the Alps get roughly ten meters of rain a year. The problem for farming in that region is not a shortage of water but rather too much. It is true that farming in Canterbury is probably over-drawing on aquifers, but that is in part because the farmers took to dairying in an area unsuitable for that activity. Prior to the dairy rush, the area was quite prosperous at farming, but without irrigation. Farmers tended to grow grain in the warm dry summers, and would also run sheep. Now wool is not really wanted, so the farmers switched.

Of course, just because I can find a problem in one place does not mean the paper does not raise a valid point. I suspect that when producing a world map like that the authors go to whatever resources they can find and may not check associated issues. So, what are the real problems? In a recent article in Physics World it was stated that within thirty years almost 80% of lands that irrigate through groundwater will reach their limits as wells run dry. It also states that for the other 20% of areas that rely on pumped groundwater, surface flow of streams and rivers has already fallen. This includes cities that depend on pumped water for a water supply. The effects are already being felt in the mid-west of the US.

This raises the question of what can we do about this problem? The most obvious answer is to use less. Most people domestically use far more than necessary, and those who rely on stored rainwater will show how to use less. At the city level, do we really need the number of home pools? On a lesser scale, how many houses really do not waste water? Irrigation needs to be managed in such a way as to lose less by evaporation (i.e. something other than sprinklers.) We need farming methods that are better suited to the local climate, except that also has the problem that we then lose production volumes, and it is far from clear we can afford that.

For coastal cities, desalination offers an answer, but it costs $US1 per 1 – 2 tonne so it is not cheap, and in terms of electrical energy, if we use reverse osmosis, roughly 5 kWh is required, which means we have to significantly increase electrical production. Reverse osmosis works by using pressure to force water through a membrane that will not permit salts to pass, so in principle it could be turned off during peak loads, which might make it useful for a base loading source like nuclear power, but this is not so useful for places distant from the coast. There is another problem with desalination. The seawater should be sterile and the membranes have to be regularly cleaned, which leads to the release of biocides, salts, chelating agents, etc into the sea, which in turn is not particularly good for the local environment.We could pipe water from somewhere else, except we may be running out of “somewhere elses”, and anyway, that place may well be what is feeding the groundwater aquifer. The unfortunate end-result is we may have to give up using so much. We have a problem, Houston!

Book Discount

From October 17 – 24, “Red Gold” will be discounted to 99c/99p. 

Mars is to be colonized. The hype is huge, the suckers will line up, and we will control the floats. There is money to be made, and the beauty is, nobody on Earth can check what is really going on on Mars. 

Partly inspired by the 1988 crash, Red Gold shows the anatomy of one sort of fraud. Then there’s Mars, and where Red Gold shows the science needed for many colonists to survive indefinitely. As a bonus there is an appendix that shows how the writing of this novel led to a novel explanation for the presence of Martian rivers.Red Gold is a thriller with a touch of romance, a little economics and enough science to show how Mars might be colonised and survive indefinitely.

Protesting on Climate Change

It is interesting these days to see the level of protest; so many people want to protest against doing something. In many cases, that is fair as what they are protesting about should not happen, but then the problem comes, what happens when they get the rhythm, and what sort of protests get results as opposed to the protestors just making a nuisance of themselves? Recently, there were widespread protests here against the inaction of governments on the issue of climate change and that is a fair enough target of protest but how should they go about it? Blocking major roads to prevent traffic from going home after work simply leads to the production of more greenhouse gas. Then there were people here who used superglue to attach themselves to windows. My view on that is they should have been identified so that any bills for damages could be sent, then they be left there. Since they glued their hands, they would need friends to even feed them and a couple of cold fronts were coming.

What I find interesting is that one of the proposed ways of attacking climate change is to plant trees and they even protest about that. They argue the trees grow, then get cut down and the CO2 is returned to the atmosphere so we are no further ahead. In my opinion, that is wrong. First, we buy time. The trees can stand for a reasonable length of time, and further, when we cut them down, we can use the wood to build houses, etc. Leaves fall and return some carbon to the soil. And, of course, when we cut them down, we can replant. But most important, from my point of view, is we can do this now. There is no king hit that will deal with climate change so we shall have to do a very large number of things and unfortunately we don’t actually know how to do many of them beneficially. There is nothing like getting started on what you can do, and that you know what the consequences of doing it are.

Another objection noted in our local paper was that, wait for it, had we started thirty years ago when we knew about the problem this might have worked, but now we need more trees than we can reasonably plant quickly. Well, maybe. It does take time to get the necessary seedlings. The argument seems to be, we can’t solve the entire crisis this way, so why bother? Yes, I know there is no king hit, but if you are going to solve this crisis with a number of different approaches, getting started now is better than not doing anything. As the callers for doing nothing argue, we only have the problem because we did nothing some time ago. Yes, it is true we have wasted a lot of time, but why will wasting more now be beneficial?

Another argument seems to be, the land is too valuable for food production to waste on planting trees. Well, if I look out the window from where I am writing this, I see a range of somewhat tortured hills that stand between 300 to 700 meters above the valley floor, and these hills proceed as hills and steep valleys for a considerable distance. They are largely devoid of big trees, despite the fact that this whole area was initially heavily forested. When the settlers came, the valley was cleared of forest for farmland (farming has now long gone, having been replaced by urban development) then the hillsides were denuded of forest for timber. Now there is light scrub in places, but the big trees are long gone, and this is typical of a lot of land here. Planting trees would stabilise a lot of such steep hillsides, which are often prone to severe erosion, especially with heavy rain, which is expected to become more common over time due to climate change, at least here. For such country where harvesting trees becomes unlikely, by planting a judicious mix of trees such a forest could be self-sustaining so once established and it would store carbon indefinitely.

There are additional benefits of forests. An article in he recent Physics World mentioned that forests decrease the effect of storms, the reason being that the rough land surface offers a frictional restraint on wind speed. The forest has to be reasonably large, and of course the beneficial effects tend to apply to places distant from the coast. The forests also offer a benefit to rainfall through evapotranspiration and it is notable that many areas that are now facing desertification in Africa once had reasonable rainfall and extensive forests. It should be emphasised that forests may also reduce total rainfall by reducing the effect of heavy tropical storms, however in general these do little to provide water in a useful form as the water runs off very quickly. Forests are also beneficial in that they hold up water from heavy rains and allow it to be absorbed by the soil, and hence be available later, and of course, reduce heavy erosion. Also, in areas prone to severe flooding, and we have seen many examples of flooded urban areas on television recently, by holding up the water and thus spreading its movement over more time, the effects of such floods are mitigated. To my mind, anything that achieves more than one benefit is far more worthwhile to pursue.

As for the argument that when the trees mature, they will be harvested and eventually the carbon will return to the atmosphere, I have two responses. First, at least some of it can be stored in buildings, where it will remain for quite some time. Second, you could burn it for fuel or convert it to biofuel, in which case the carbon will return quickly, several decades in the future, but it displaces fossil carbon you would have otherwise converted to CO2, so you are still ahead. Finally, you have bought time to develop new means of solving this problem. And, at the same time, you do generate a future resource, in some cases from land that is otherwise producing nothing except erosion. From my point of view, it probably does not matter whether we act because I shall be dead by the time the really worst of the consequences arrive. However, I would like my grandchildren’s children to have a reasonable chance at life, and that means that we must stop protesting against change because our society cannot continue this way. Change will come; the issue is, what sort of change? Let us control it and make it beneficial.

An Ugly Turn for Science

I suspect that there is a commonly held view that science progresses inexorably onwards, with everyone assiduously seeking the truth. However, in 1962 Thomas Kuhn published a book “The structure of scientific revolutions” that suggested this view is somewhat incorrect. He suggested that what actually happens is that scientists spend most of their time solving puzzles for which they believe they know the answer before they begin, in other words their main objective is to add confirming evidence to current theory and beliefs. Results tend to be interpreted in terms of the current paradigm and if it cannot, it tends to be placed in the bottom drawer and is quietly forgotten. In my experience of science, I believe that is largely true, although there is an alternative: the result is reported in a very small section two-thirds through the published paper with no comment, where nobody will notice it, although I once saw a result that contradicted standard theory simply reported with an exclamation mark and no further comment. This is not good, but equally it is not especially bad; it is merely lazy and ducking the purpose of science as I see it, which is to find the truth. The actual purpose seems at times merely to get more grants and not annoy anyone who might sit on a funding panel.

That sort of behaviour is understandable. Most scientists are in it to get a good salary, promotion, awards, etc, and you don’t advance your career by rocking the boat and missing out on grants. I know! If they get the results they expect, more or less, they feel they know what is going on and they want to be comfortable. One can criticise that but it is not particularly wrong; merely not very ambitious. And in the physical sciences, as far as I am aware, that is as far as it goes wrong. 

The bad news is that much deeper rot is appearing, as highlighted by an article in the journal “Science”, vol 365, p 1362 (published by the American Association for the Advancement of Science, and generally recognised as one of the best scientific publications). The subject was the non-publication of a dissenting report following analysis on the attack at Khan Shaykhun, in which Assad was accused of killing about 80 people with sarin, and led, 2 days later, to Trump asserting that he knew unquestionably that Assad did it, so he fired 59 cruise missiles at a Syrian base.

It then appeared that a mathematician, Goong Chen of Texas A&M University, elected to do some mathematical modelling using publicly available data, and he got concerned with what he found. If his modelling was correct, the public statements were wrong. He came into contact with Theodore Postol, an emeritus Professor from MIT and a world expert on missile defence and after discussion he, Postol, and five other scientists carried out an investigation. The end result was that they wrote a paper essentially saying that the conclusions that Assad had deployed chemical weapons did not match the evidence. The paper was sent to the journal “Science and Global Security” (SGS), and following peer review was authorised for publication. So far, science working as it should. The next step is if people do not agree, they should either dispute the evidence by providing contrary evidence, or dispute the analysis of the evidence, but that is not what happened.

Apparently the manuscript was put online as an “advanced publication”, and this drew the attention of Tulsi Gabbard, a Presidential candidate. Gabbard was a major in the US military and had been deployed in Syria in a sufficiently senior position to have a realistic idea of what went on. She has stated she believed the evidence was that Assad did not use chemical weapons. She has apparently gone further and said that Assad should be properly investigated, and if evidence is found he should be accused of war crimes, but if evidence is not found he should be left alone. That, to me, is a sound position: the outcome should depend on evidence. She apparently found the preprint and put it on her blog, which she is using in her Presidential candidate run. Again, quite appropriate: resolve an issue by examining the evidence. That is what science is all about, and it is great that a politician is advocating that approach.

Then things started to go wrong. This preprint drew a detailed critique from Elliot Higgins, the boss of Bellingcat, which has a history of being anti-Assad, and there was also an attack from Gregory Koblentz, a chemical weapons expert who says Postol has a pro-Assad line. The net result is that SGS decided to pull the paper, and “Science” states this was “amid fierce criticism and warnings that the paper would help Syrian President Bashar al-Assad and the Russian government.” Postol argues that Koblentz’s criticism is beside the point. To quote Postol: “I find it troubling that his focus seems to be on his conclusion that I am biased. The question is: what’s wrong with the analysis I used?” I find that to be well said.

According to the Science article, Koblentz admitted he was not qualified to judge the mathematical modelling, but he wrote to the journal editor more than once, urging him not to publish. Comments included: “You must approach this latest analysis with great caution”, the paper would be “misused to cover up the [Assad] regime’s crimes” and “permanently stain the reputation of your journal”. The journal then pulled the paper off the publication rank, at first saying they would edit it, but then they backtracked completely. The editor of the journal is quoted in Science as saying, “In hindsight we probably should have sent it to a different set of reviewers.” I find this comment particularly abhorrent. The editor should not select reviewers on the grounds they will deliver the verdict that the editor wants, or the verdict that happens to be most convenient; reviewers should be restricted to finding errors in the paper.I find it extremely troubling that a scientific institution is prepared to consider repressing an analysis solely on grounds of political expediency with no interest in finding the truth. It is also true that I hold a similar view relating to the incident. I saw a TV clip that was taken within a day of the event where people were taking samples from the hole where the sarin was allegedly delivered without any protection. If the hole had been the source of large amounts of sarin, enough would remain at the primary site to still do serious damage, but nobody was affected. But whether sarin was there or not is not my main gripe. Instead, I find it shocking that a scientific journal should reject a paper simply because some “don’t approve”. The reason for rejection of a paper should be that it is demonstrably wrong, or it is unimportant. The importance cannot be disputed, and if it is demonstrably wrong, then it should be easy to demonstrate where it is wrong. What do you all think?

The Hydrogen Economy

Now that climate change has finally struck home to at least some politicians, we have the problem, what to do next. An obvious point could be that while the politicians made grandiose promises about it thirty years ago, and then for economic reasons did nothing, they could at least have carried out research so they knew what their options are so that when they finally got around to doing something, they knew what to do. Right now, they don’t. One of the possibilities for transport is the use of hydrogen, but is that helpful? If so, where? The first point is you have to make your hydrogen. That is easy: you pass electricity through water. There is no shortage of water but you still have to generate your electricity. This raises the question, how, and at what cost? The good news is that generating hydrogen merely consumes energy so it can be turned down or off at peak load periods, but the difficulty now is the renewables everyone is so happy about offer erratic loads. As an example, Germany is turning off its nuclear power stations and finds it has to burn more coal, especially when the wind is not blowing. 

Assume we have the electricity and we have hydrogen, now what? The hydrogen could be burned directly in a compression motor, or used to power fuel cells. The latter is far more energy efficient, and we can probably manage about 70% overall efficiency. The reason the fuel cell is more desirable than the battery is simply that the battery cannot contain the desired energy density. The advantages of hydrogen include it is light and when burned (including in a fuel cell) all it makes is water. Water is a very powerful greenhouse gas, but the atmosphere has a way of promptly removing excess: rain.

However, hydrogen does have some disadvantages. A hydrogen-air mix is explosive over a rather wide mix ratio. Even outside this ratio, it has a clear flammability and an exceptionally fast flame speed, it leaks far faster than any other gas other than, possibly, helium, and it is odourless and colourless so you may not know it is there. But suppose you put that behind you, there are still clear problems. A small fuel cell car would need approximately 1 kg of hydrogen to drive 100 km. Now, suppose we need a range of 500 km. The storage of 5 kg of hydrogen would take up most of the boot space if you use a tank that is pressurised to 700 bar. (1 bar is atmospheric pressure.) That requires a lot of energy to compress the gas, and it adds a significant weight to the reinforced tank, which you most certainly do not want to rupture. The volume is important for a small car. You wish to go on holiday, then find your boot is occupied by a massive gas tank. However, this is trivial for very large machines, and a company in the US makes hydrogen powered forklifts. Here, a very heavy counterballancing weight is required so a monstrous steel tank is actually an asset. I previously wrote a blog post on hydrogen for vehicles, here.

There are different possible ways to store hydrogen. For those with a technical bent, the objective is to have something that absorbs hydrogen and binds it with an energy of between 15 – 20 kJ/mol. That is fairly weak. If you can mange that range you can store hydrogen at up to 100 bar with good reversibility. If you bind it in metal hydrides, you get a better density of storage at atmospheric pressure, but the difficulty is then to get the hydrogen back out. Most of the proposed metal organic absorbers bind it too weakly and you can’t get enough in. The metals that strongly absorb can be made to release it easier if the metal is present as nanoparticles, and to prevent these clumping, they can be embedded into carbon. There is an issue here, though, that the required volume is starting to become large for a given usage range because there are so many components that are not hydrogen.

There is another problem with hydrogen that most overlook: how do you deliver it to filling stations? Pressurizing won’t work because you can’t get enough into any container to be worth it. You could ship liquefied hydrogen, but it is only a liquid at or below -253 degrees Centigrade. It takes a lot of energy to cool that far, a lot to keep it that cold, and the part that most people will not realize is that at those very low temperatures for very light atoms, there are some effects of quantum mechanics that have to be taken into account. One problem is that hydrogen occurs as two isomers: ortho and para hydrogen. (Isomers are where there are at last two distinctly different forms with the same components, that may or may not readily interconvert.)  These arise because the hydrogen molecule comprises two protons bound by two electrons. The protons have what we call nuclear spin and as a consequence, have a magnetic moment. In ortho hydrogen, the spins are aligned; in para they are opposed. At room temperature, the hydrogen is 75% in the ortho form, but this is of higher energy than the para form. Accordingly, if you just cool hydrogen to the liquid form, you get the room temperature mix. This slowly converts to the para form, but it gives off heat as it does so. That means a tank of liquid hydrogen slowly builds up pressure. To be used as liquid hydrogen it is probably best to let it switch to the para form first, but that takes a lot more energy maintaining the low temperatures while the conversion is going on. Currently, liquefying hydrogen takes 12 kWh of power per kilogram of hydrogen, which is about 25% that of what you get from a fuel cell. In practice, you may need almost that much again to keep it cold, and since this power has to be electrical, we have an even greater demand for electricity.

So, is there an answer? My feeling is still that hydrogen is not the most desirable material for a fuel cell, from the point of view of usage in transport. The reason it is pursued is that it is easiest to make a fuel cell work with hydrogen. There are alternatives. Two that come to mind are ammonia and methanol. Both can drive fuel cells, and ammonia reacts to give water and nitrogen while methanol reacts to give water and carbon dioxide. Currently, the ammonia cell may be more efficient, but ammonia is somewhat difficult to make, although there is evidence it can be made from hydrogen and nitrogen under mild conditions. The methanol fuel cell has a problem that too much of the methanol sneaks through the membrane that keeps the two sides of the cell separate, and carbon monoxide tends to poison electrodes. Methanol could be made by the reduction of carbon dioxide from the air with solar energy.

So where does that leave us? In my opinion, what we need more than anything else is progress on better performing methanol or ammonia fuel cells, or some better fuel cell. My preference for the fuel cell is simply an issue of weight and power density, and I do not see hydrogen as being useful for light vehicles. The very heavy machines are a different matter, and batteries will never adequately power them. The problem of energy production in the future is a real one, and I feel we need to do a lot more research to pick the better options. We should have been doing this over the last thirty years, but we didn’t. However, there is no point in moaning about time wasted; we are here, and we have to act with a lot more urgency. However, it is not right to use the easiest but not very good options; we need to get these problems right.