Natural organic acid hydrophobic modified alkaline hydroxylated charcoal based on supercritical CO2 medium as well as preparation method and application of biochar

Abstract

The invention discloses natural organic acid hydrophobic modified alkaline hydroxylated biochar based on a supercritical CO2 medium as well as a preparation method and application of the biochar. The method comprises the following steps: (1) adding acetone into biochar, performing mixing, and carrying out ultrasonic treatment, filtering and washing to obtain clean biochar; (2) adding hydrochloric acid with stirring, and performing filtering, washing, and drying in an inert gas atmosphere to obtain dried biochar; (3) adding the dried biochar into an alkali solution, performing heating and stirring, performing filtering, and performing drying in an inert gas atmosphere to obtain hydroxylated biochar; (4) adding the hydroxylated biochar into a solution in which natural macromolecular organic acid, absolute ethyl alcohol and a dehydrating agent are dissolved, and performing heating reaction in a supercritical CO2 medium to obtain a reacted mixed solution; and (5) washing the filtered precipitate, and performing drying in an inert gas atmosphere to obtain the modified biochar. The modified biochar is simple to operate, low in price, green and environment-friendly, has small influence on the pore structure of the carbon material, and has good adsorption performance on volatile organic compounds in a high-humidity environment.

Description

technical field [0001] The invention belongs to the field of porous carbon materials, in particular to carbon dioxide based on supercritical CO 2 Hydrophobic modification of alkaline hydroxylated biochar with natural organic acid as a medium and its preparation method and application. Background technique [0002] In recent years, extreme air pollution events have occurred frequently in China, such as PM 2.5 Haze caused by O 3 The characteristic photochemical smog has seriously affected human health and atmospheric environmental quality. At present, adsorption technology and adsorption-catalytic combustion technology are the main technologies for the effective treatment of medium and low concentration organic waste gas. Among them, adsorbent has become one of the key materials, and carbon-based hierarchical porous materials are widely used as adsorbents for VOCs due to their wide range of sources, such as activated carbon, biochar, biochar fibers, etc., low price and exce...

AI Technical Summary

Problems solved by technology

Additionally, some coatings such as organosilanes and perfluorinated compounds tend to be toxic, flammable, corrosive, difficult to handle and damaging to the environment

However, the application of natural macromolecular organic acid-modified hydrophobic carbon materials for VOCs adsorption in high-humidity environments has rarely been reported.

Therefore, the development of hierarchically porous carbon materials with high hydrophobicity as high-efficiency VOCs adsorbents is expected to overcome the shortcomings of existing carbon materials such as low adsorption capacity and poor adsorption performance in competition with water vapor, and has a good application prospect.

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