Graphene oxide is an important graphene derivative. It was mainly used as a precursor for macro-preparation of graphene. In recent years, graphene oxide has attracted more and more attention due to its unique physical and chemical properties and broad application prospects. Pay attention. Due to the presence of a large number of oxygen-containing functional groups, graphene oxide has good dispersibility in water, and is easy to assemble and functionalize. Therefore, it is widely used in the preparation of multi-functional separation membranes, high-conducting high-strength fibers, ultra-light super-elastic aerogels, and many more. This kind of functional material shows good prospects in electrochemical energy storage, catalysis, biomedicine, and composite materials. At present, graphene oxide is mainly prepared by stripping graphite oxide. The production of graphite oxide has been more than 150 years old so far. Both the Brodie method (1859) and the later Staudenmaier and Hummers methods have been based on graphite and large amounts of concentrated nitric acid, concentrated sulfuric acid, and potassium permanganate. The reaction of complex strong oxidants, not only the risk of explosion, but also serious pollution and long reaction period. Taking the most commonly used Hummers method as an example, the oxidant consists of concentrated sulfuric acid and potassium permanganate, and its typical material ratio (mass ratio) to graphite is 40:3:1 (concentrated sulfuric acid: potassium permanganate:graphite). The reaction will eventually produce more than 1000 parts by mass of acidic wastewater. Also, high activity Mn2O7 intermediates may explode at high temperatures and the oxidation reaction may take hours to hundreds of hours to complete. Recently, the Advanced Carbon Materials Research Department of Shenyang National Institute of Materials Science, Institute of Metal Research, Chinese Academy of Sciences, proposed a new method for the oxidation of electrolyzed water. It broke the traditional idea of ​​oxidizing graphite through strong oxidants for more than 150 years and realized graphene oxide. Safe, green, ultra-fast preparation. The method first intercalates graphite in concentrated sulfuric acid and then oxidizes the intercalated graphite in dilute sulfuric acid. Oxygen isotope tracer and free radical trapping experiments show that the oxygen in the graphene oxide is mainly derived from the water in the electrolyte, and a large amount of highly reactive oxygen radicals generated by the electrolysis of water react with graphite to generate graphene oxide. There is almost no loss of sulfuric acid in the reaction, and no other substances are generated, and it can be reused in electrochemical reactions. It has also been found that the oxidation rate of graphene oxide prepared by the oxidation of electrolyzed water is more than 100 times faster than the existing method, and the obtained material is similar to the existing method and is easily and continuously prepared. The method effectively solves the problems of long-term explosion risk, environmental pollution, and long reaction period for the preparation of graphene oxide, which may significantly reduce the preparation cost and promote the industrial application of graphene oxide. The relevant research results were published in Nature-Communications, and related technologies have applied for Chinese invention patents and PCT patents. The study was funded by the Ministry of Science and Technology's key research and development program, the National Natural Science Foundation of China's Outstanding Youth Fund, major projects, and innovation group projects.
Laser stop is a device used in warp knitting machines to stop the knitting process at a specific point. It is typically used to create patterns or designs in the fabric being produced. The laser stop works by emitting a beam of light that is detected by a sensor in the machine. When the beam is interrupted by a pre-programmed pattern, the machine stops knitting at that point. This allows for precise control over the knitting process and can be used to create intricate designs that would be difficult or impossible to achieve with traditional knitting methods. The use of laser stops is becoming increasingly common in the textile industry as manufacturers seek to differentiate their products and offer more customization options to customers.
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