Rust is something we often see in our daily lives, ranging from nails and screws to metal machinery. These annoying metal "viruses" are not only very easy to shorten the life of metal products, but they are also. very harmful. However, the latest research shows that this nasty rust appears to have positive effects, such as being used to generate electricity.
In a paper published last month in the Proceedings of the National Academy of Sciences, chemistry professors Tom Miller of Caltech and Franz Geiger of Northwestern University Franz Geiger proposed a device for producing Energy powered by rust and movement to power devices. ranging from headlights to medical implants.
The operation of this rust-proof power generation equipment is based on a principle called electrokinetic effect, and its overall operation is very ccomplex. Simply put, its basic principle is: ions in salt water attract electrons from the iron alloy beneath the rust layer (iron oxide). When salt water flows, ions flow with it and carry away electrons, generating an electric current. In terms of efficiency, the conversion rate of electrical energy by electrokinetic effect is also very high. The conversion efficiency of kinetic energy into electrical energy is about 30%, while the electrical energy conversion efficiency of today's best solar panels is only about 20%. .
In fact, in addition to rust films, researchers can also use graphene to generate electricity in the laboratory. When salt water falls on graphene, electricity will be generated. Graphene is a nanomaterial made of thin sheets of carbon atoms that is also used as a materialNegative electrode for lithium-ion batteries in electric and electronic vehicles. However, the problem of using graphene is that it is very expensive and the manufacturing process and expansion of graphene films is very complicated, while producing large iron oxide films, it that is to say rust, is relatively easy.
After all, rust is everywhere and often spreads unintentionally, especially on cars and boats, buoys and docks that are soaked in seawater for long periods of time. Even though it doesn't grow in a natural environment, people can easily create rust by exposing iron objects to water.
5 ways to tell salt water from pure water
The higher the temperature of the salt water, the lower the resistance.
Reason: Salt water ionizes to produce chloride ions and sodium ions. The higher the temperature,The faster the ions move, the easier it is to conduct electricity, so the resistance is smaller.
NaCl is an electrolyte.
An electrolyte is a compound that can conduct electricity (self-ionize into cations and anions) when dissolved in an aqueous solution or in the molten state. Can be divided into strong electrolytes and weak electrolytes. It can only conduct electricity after ionizing free ions when dissolved in water or in a molten state. Ionic compounds can conduct electricity in aqueous solutions or in the molten state; some covalent compounds can also conduct electricity in aqueous solutions, but there are also solid electrolytes whose conductivity comes from the migration of ions in the crystal lattice.
Put silver nitrate in the water. The white precipitate is salt water and the white precipitate is pure water.
Take twoElectrictrode DC is inserted into the water if there are bubbles it is salt water, and if there are no bubbles it is pure water.
Put an apple in water. The reason why apple shrinks is salt water. The apple in pure water should swell slightly.
Put the iron block in the water. After one night, the rust will be more from salt water and less from pure water. The iron block should be partially exposed to air.
Put a cotton thread in the water and leave part of it out. After one night, if there are crystals precipitating between the cotton thread and the water surface, it is salt water, and if there are no crystals. , it is pure water.
The first consists of generating a white precipitate of AgCl.
The second is the electrolysis reaction.
The third is osmotic balance in biology.
The fourth reason is that salt can accelerate the oxidation of active metals.
The fifth reason is qThe salt water present on the cotton thread evaporates quickly, causing the salt particles to precipitate.
It's pretty clear.