Chemical Engineering in Life – Question 33: How to avoid dying of thirst in the desert? Standard answer already available
Thread Content
This post was last edited by yjqin1 on 2015-9-26 at 10:22. Last year, I gave a presentation to students in grades 10, 11, and 12 at one of the best high schools in Xinjiang; there was a huge crowd there. It was the first time I had encountered such a large audience, but I wasn’t scared – it was only an hour and a half, and I didn’t need any script. I had organized my thoughts in advance. How great is this school? Put it this way: over the past decade or so, 40% of those who were admitted to Tsinghua and Peking University in Xinjiang came from this school. The opening statement goes like this: I currently live in NJ, somewhere between New York and Philadelphia – it’s roughly the size of Langfang, which is located between Beijing and Tianjin; it’s nothing compared to Xinjiang. Just how great is this Jersey cow? There’s nothing special about it; I simply live in a town called Newton. In the towns nearby, there lived two great people, both with the last name “Einstein” – one was Edison and the other was Einstein. The students shouted together: Wow, cow! It says: I’ve just returned from the Taklamakan Desert. What did I do there? I found that in that desert, smoke rose straight into the air (natural gas couldn’t be transported out, so it had to be burned at the wellheads). To obtain gasoline from that smoke, a steam permeation membrane is used to separate C4+, which yields high-quality gasoline with a high octane rating; this gasoline can then be transported using vehicles designed for the desert. At the same time, I found that the deserts in the interior of the Tarim Basin are not lacking in life; the most important thing is water. But it can’t drink it; if it does, it will die. Next, have your mother put four items in your travel bag – four common items; with them, you won’t die of thirst even if you get lost in the desert. These three items are a small bottle of slaked lime (calcium hydroxide), a small bottle of sodium carbonate, a small bottle of citric acid, and a water cup. After the speech, students rushed over to get my signature, and some even bought popular science books on membrane separation for me to sign. I felt dizzy at that moment; it was really like I had become a star. There is water in the desert, but drinking it kills you. Why then, with these four items (a small bottle of slaked lime, a small bottle of sodium carbonate, a small bottle of citric acid, and a water cup), one doesn’t die of thirst? Please explain
2C6H8O7*H2O + Na2CO3 = 2NaC6H7O7 + CO2 + 3H2O; CO2 + Ca(OH)2 = CaCO3↓ + H2O；
To survive in the desert, one should drink enough water, carry sufficient water, learn how to find water, and travel at night and camp during the day.
That’s it then. . . . . .
These items are definitely meant for saving one’s life.
Where plants grow, there must be water underground, although it may not be potable.
In the thin layer beneath the sand, traces of water can be seen.
This is probably what everyone imagines a desert to be, right? But there are still green plants. The presence of plants indicates the existence of water underground, even at great depths.
This post was last edited by yjqin1 on 2015-9-26 at 10:28. Standard answer: What should you do if you are traveling in the desert and find that the drinking water you have with you is not enough? Surely they must be worried and trying to get in touch with the outside world. But not all deserts have signal coverage like those in China. Moreover, the Taklamakan Desert in the Tarim Basin is 1,000 kilometers long from east to west, 400 kilometers wide from north to south, and covers an area of 330,000 square kilometers. Out of instinct, one seeks a source of water. Where can I find it? Look in low places, look where there are plants. It’s best to have surface water; if not, then digging is necessary. There’s no need to rush – take your time. Water might start seeping out in a moment. Taste it – is it salty or bitter? If it’s neither salty nor bitter, drink some of it; try to carry as much as possible in a container, and then find a way out. If it’s salty, really salty, I don’t have an easy solution right now either. There are patents, many different kinds of them, including my patent based on the membrane distillation principle. That means using very expensive desert travel equipment. What if the water isn’t salty, but it’s very bitter? So your mother (why not say your wife?) It seems that wives, as a species, have degenerated to having only a few simple functions: eating you, drinking from you, shouting at you, and acting cute around you. That’s when the useful tips I’ve prepared for you come in handy. The groundwater in inland river regions is generally brackish, containing not only sodium chloride but also sulfate ions, bicarbonate ions, magnesium ions, calcium ions, and others. In particular, the calcium sulfate concentration is very high, nearly saturated. If one drinks water containing nearly saturated calcium sulfate for a long time, the semipermeable membranes in the kidneys will definitely be covered by calcium sulfate, and uremia is no joke. Too much magnesium can also disrupt bodily functions. How did Yang Bailao die in \"The White-Haired Girl\"? Now I’ll start explaining how to use these various treasures. Use a container such as an empty mineral water bottle, fill it with brackish water, and then add slaked lime or quicklime powder that has been sealed inside the bottle (why seal it? ), it needs to be stirred, even by hand. Generally, the following reactions occur: Ca(OH)2 + HCO3- = Ca2+ + CO32- + H2O; Ca(OH)2 + Mg2+ = Ca2+ + Mg(OH)2 (precipitate); Ca2+ + CO32- = CaCO3 (precipitate); Ca2+ + SO42- = CaSO4 (precipitate, with slightly higher solubility). This results in the removal of most magnesium ions and bicarbonate ions, as well as some sulfate ions. However, too much lime should not be added, otherwise it still amounts to increasing the salt content in the water. How to add the right amount of lime? I don’t know either; it’s better to have less rather than more. It can’t hurt to use materials sparingly, right? Step 2: Pour the supernatant from the aforementioned container into another container, and then add sodium carbonate to it in order to remove any remaining calcium ions: Ca2+ + CO32- = CaCO3 (precipitate). The supernatant resulting from this process is then poured into the first container, which has been cleaned with brackish water. Such supernatant is alkaline, with a pH ranging from 9 to 11.6; the taste of such water is definitely poor. At this point, take out the third treasure, citric acid (solid), and add an appropriate amount of it; this will result in the following reactions: C6H8O7 + CO32- = C6H5O7 3- + HCO3-; C6H8O7 + HCO3- = C6H5O7 3- + H2O + CO2 (released as gas). Then, taste the water that has been prepared in this way to see what it tastes like It should taste similar to salty soda. Of course, if white sugar is mixed into the citric acid in advance, it becomes a sweet-and-salty soda, and thus a new type of soda is created. If it is not too bitter (due to incomplete removal of magnesium ions), too astringent (due to too high pH), or too salty, this water is drinkable. It’s too astringent; add more citric acid ； It’s too bitter; you have to start over. The net result of the overall process is that the vast majority of calcium ions and magnesium ions are removed, and it is possible that most sulfate ions are also removed; the sodium ion concentration increases, but the chloride ion concentration does not increase. Citric acid also has some nutritional benefits.
Hehe, I learned it! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !