Simultaneously high-efficiency silicon release and heavy metal adsorption modified biochar and preparation method

Abstract

A modified biochar that releases silicon efficiently and absorbs heavy metals at the same time and a preparation method thereof. The preparation method of the modified biochar includes the following steps: S1, crushing straw; S2, mixing the crushed straw with a concentration of 0.05mol / L~ 0.5mol / L sodium citrate solution is mixed according to the ratio of 1:6~1:10 (m:v), stirred evenly under the condition of 20~30°C, and then left to let it fully infiltrate, so as to modify the straw; S3 1. Dry the modified straw after crushing; S4. Pyrolyze the modified straw obtained in step S3 at 500-600° C. for 2-3 hours in an oxygen-isolated environment, and obtain sodium citrate modified organisms after cooling. carbon material. The invention uses straw as a raw material and prepares a novel biochar material by means of sodium citrate modification, which is used in agricultural production activities and can achieve the dual purposes of effectively supplying nutrient element silicon in soil and adsorbing and fixing heavy metals.

Description

technical field [0001] The invention relates to the technical field of farmland soil treatment, and more specifically relates to a sodium citrate modified biochar material that simultaneously efficiently releases plant-available silicon and absorbs heavy metals, as well as its preparation and application. Background technique [0002] With the continuous development of the agricultural economy, a large area of ​​farmland in my country is facing the depletion of plant-available silicon. Especially for the paddy soil in South China, due to the weathering and leaching of the soil due to high temperature and rainy climate conditions, the effective silicon content is low, and the proportion of silicon-deficient soil is as high as 70%. Therefore, at present, most paddy soils need to apply appropriate amount of silicon fertilizer to make up for the shortage of silicon in the soil. However, traditional silicon fertilizers are mainly slag silicate and natural silicate minerals, which...

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Problems solved by technology

The inventor realized that because rice is a silicon-rich plant, biochar prepared from rice straw contains a large amount of silicon, and choosing rice straw to prepare biochar can not only promote the resource utilization of straw, but also solve the problem of silicon deficiency in farmland soil. At the same time, biochar material has the advantages of large specific surface area, rich surface functional groups, and rich pore structure. It is an excellent adsorption material and can be used for the adsorption and fixation of heavy metal pollution in farmland. The ability of carbon materials to effectively supply silicon for plants to use is relatively weak, and the ability to adsorb and fix heavy metals is limited.

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