Plasma-modified carbon nanotubes make progress in pollutant treatment

Low-temperature plasma-modified grafting is a treatment technology that has a short treatment time, does not produce chemical pollution, does not damage the overall volume structure of the material, and only changes the surface properties of the material. In recent years, the research group of Chen Changlun, Shao Dadong, Hu Jun, Wang Xiangke, etc. of the “Cryogenic Plasma Application Research Lab” of the Institute of Plasma has used low temperature plasma technology to modify the surface of carbon nanotubes, which has overcome the difficulties The problems caused by solubility have greatly improved its practical application. After modifying and assembling carbon nanotubes with low -temperature plasma technology, the research group applied them to environmental pollutant detection and treatment research and achieved a series of results. The first is to use Ar / H2O, Ar / NH3, and Ar / O2 microwave plasma to surface-treat carbon nanotubes to introduce oxygen-containing, amino-containing functional groups on the surface, and improve the hydrophilicity and carbon nanotubes. Dispersibility makes it possible to prepare nano solutions. These processed (surface-modified) functionalized materials have good application prospects for improving the adsorption of carbon nanotubes on biological and environmental pollutants. Some research results were published in Applied Physics Letter (2010, 96, 131504); Carbon (2010, 48, 939-948); The Journal of Physical Chemistry C (2009, 113, 7659-7665); Diamond & Related Materials (in press ); And was invited to make 2 oral presentations at international conferences . Second, the surface of carbon nanotubes is activated by N2 radio frequency plasma, and then organic monomers and natural polymer materials are grafted to prepare carbon nanotube / organic composite materials. The surface of the composite material prepared by plasma has various functional groups. These functional groups have strong adsorption and complexation ability to persistent organic pollutants (POPs), toxic and harmful heavy metal ions, and radionuclides, thereby improving the composition. Material's ability to adsorb pollutants. Some research results were published in The Journal of Physical Chemistry B (2009, 113, 860-864); Chemosphere (2010, 79, 679-685); Plasma Processes and Polymers (in press, and selected as cover) . The third reason is that the small size of carbon nanotubes makes it difficult to recover and recycle nanomaterials after adsorbing and treating organic / inorganic pollutants. The traditional centrifugation method requires a high rotation speed, and the filtration method is liable to cause clogging of the filtration membrane. If carbon nanotubes that adsorb pollutants enter the environment, secondary pollution will occur. In response to the above problems, the research group used a sol-gel method to first assemble iron oxides on carbon nanotubes, and then activated the carbon nanotube / iron oxide surface with N2 RF plasma, and grafted organic monomers And natural macromolecular materials to prepare magnetic multiple composite nanomaterials. The magnetic composite nanomaterials not only have high adsorption performance, but also the magnetic separation technology can simply and conveniently separate magnetic composite nanomaterials from solution, which solves the solid-liquid problem. Separated problems can be applied to practical work at the same time. Some rcelated research results were published in Environmental Science and Technology (2009, 43, 2362-2367); Journal of Hazard Material (2009, 164, 923-928); Journal of Physical Chemistry B (jp-2009-11424k). This work has been supported by the National Natural Science Foundation of China, the Ministry of Science and Technology's 973 major research plan "Application of Nanomaterials for Trace Detection and Treatment of Persistent Toxic Pollutants", a major project of the Hefei Institute of Material Science of the Chinese Academy of Sciences, a talent project of Hefei Research Institute, and Spark The project, the Chinese Academy of Sciences Key Laboratory Fund for New Thin Film Solar Cells and other funds. Material surface modification, plasma treatment instrument Tel: 0519- 86900935 8666730.

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Storage life of several vegetable seeds

The germination rate of vegetable seeds is closely related to the storage life. Different types of vegetables have different seed storage life. (I) Tomato species can generally be stored for 3-4 years, not more than 4 years, otherwise the germination rate will be reduced. The method of identifying new and old seeds: there are many small hairs on the new seeds, and they have a tomato flavor; there is less hair or shedding on old seeds, and the smell is small. (2) Cucumber seeds can be stored for 3 years. After this period, the germination rate is generally reduced by 20% -30%. Even if some can germinate, they cannot grow true leaves after emergence, which makes it difficult to survive. (3) Eggplant seeds can be stored for a slightly longer time, and seeds that are generally less than 6 years old are available. The outer skin of new seeds is shiny, but the gloss will fade as the storage period prolongs. (4) The storage time of pepper seeds should not exceed 3 years, otherwise the germination rate will decrease. According to tests, the germination rate of new seeds is above 89%, about 79.8% for 2 years and about 47% for 3 years. The golden-yellow ones are new seeds, and the apricot-yellow ones are old seeds. (5) Spring onions The new spring onions must be used in the spring of that year. If the seeds of the previous year are used, the spring onions will bear seeds. (6) Coriander seeds must be stored for 1 year before use, but the storage time should not exceed 3 years. The smell of new seeds coriander is strong, and the smell of old seeds coriander becomes weak. (7) Celery seeds can be stored for 3 years. New seeds of the year cannot be used. They must be stored for 1 year before being used. (8) Cabbage seeds can be stored for 2 years. Seeds are harvested in the same year and sown in the same year. If the storage period is more than 2 years, the emergence rate is generally reduced by 20% -27%, and the disease resistance will be reduced. Material surface modification, plasma treatment instrument Tel: 0519- 86339772 8666730

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Research progress of surface modified polymer materials by plasma technology

Compared with metal materials, polymer materials have many advantages, such as low density, low specific strength and specific modulus, good corrosion resistance, simple molding process, low cost, excellent chemical stability, good thermal stability, and Electrical performance, extremely low friction coefficient, good lubrication and excellent weather resistance, etc., so it is widely used in packaging, printing, agriculture, light industry, electronics, instrumentation, aerospace, medical equipment, composite materials and other industries [1] . Polymers have molecular designability, and different groups can be introduced on the surface through plasma surface effects to improve their properties, such as hydrophilicity, hydrophobicity, wettability, and adhesion; introduction of biologically active molecules or organisms Enzymes to improve their biocompatibility. The use of plasma technology to modify the surface of polymer materials not only improves the applicable performance of polymer materials in specific environments, but also broadens the scope of application of conventional polymer materials.It has many advantages: easy operation and a wide range of monomer selection ; Give the modified surface various excellent properties; The thickness of the surface modified layer is extremely thin (from a few nanometers to hundreds of nanometers), only the surface properties of the material are changed, and the overall properties of the substrate are unchanged; ultra-thin, uniform, Continuous and non-porous high-functional film, and the film has strong adhesion on the substrate, which is convenient for film formation on the surface of various carriers. The unique surface modification effect of plasma technology provides a new way for polymer material modification. The methods for surface modification of polymer materials using plasma technology generally include plasma treatment, plasma polymerization, and plasma graft polymerization.

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