The adsorption purification method is one of methods for extracting, separating and enriching useful components or harmful components from a dilute solution using a purifying agent. The principle flow of the adsorption purification method is similar to the ion exchange method, which mainly includes two basic operations of adsorption and desorption. Commonly used adsorbent activated carbon, sulfonated coal and certain natural adsorbents, such as soft manganese ore, apatite, kaolin, and zeolite industrially. Natural adsorbents are mainly used for water purification and wastewater treatment. Activated carbon is mainly used for the extraction of gold and silver; for further adsorption of platinum, palladium, osmium from a dilute chloride solution; can adsorb rubidium, samarium, yttrium, and other elements; even rhenium and molybdenum can be selectively separated from the acid solution In addition, it is also widely used in wastewater purification, chemical analysis and other fields. It can be seen that activated carbon is a widely used adsorbent. Therefore, mastering and understanding the adsorption performance of activated carbon is of great benefit to the use of activated carbon. The preparation of activated carbon is to subject the solid carbon materials (such as coal, wood, hard husk, core, sugar, resin, etc.) to high temperature (600 ° C ~ 900 ° C) carbonization under air-insulated conditions; then at 400 ~ 900 ° C A porous substance obtained by oxidizing and activating with air, carbon dioxide, water vapor or a mixed gas thereof under the conditions. Therefore, the preparation of activated carbon can be divided into two stages of carbonization and activation; the carbonization stage can volatilize substances other than carbon, and the oxidation activation stage can burn off residual volatile substances to generate new pores and expand the original pores to improve the microporous structure. Increase its adsorption activity. The adsorption performance of activated carbon depends on the chemical properties of the gas during oxidation activation, its concentration, activation temperature, degree of activation, and the composition and content of inorganic substances in the carbon, which are mainly determined by the nature of the activation gas and the activation temperature. Activated carbon is a porous substance, so its surface area is one of the main technical indicators to measure its adsorption. Generally, the more developed the microporous structure, the larger the surface area and adsorption activity. There is a considerable amount of hydrogen and oxygen in the activated carbon, which is generally considered to be chemically bonded to the carbon in the form of a surface complex. The content of hydrogen and oxygen in the charcoal decreases as the activation temperature increases. The ash content of activated carbon has a great influence on the performance of activated carbon. The higher the ash content, the smaller the active surface area and the lower the adsorption activity; generally it can be soaked with hydrochloric acid or hydrofluoric acid (such as 1% HCl or HF), and then washed with water to remove or reduce the ash content of the activated carbon. The ash content of activated carbon is related to the source of its raw materials. The content of this article is for reference only and does not constitute investment advice. Investors accordingly
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