A method for P25 catalytic oxygen decomposition of low-rank coal to produce water-soluble humic acid organic fertilizer

Abstract

The invention relates to a method for producing a water-soluble humic acid organic fertilizer by catalytic oxidation decomposition of low-rank coal with P25. The method comprises the following steps:under ultraviolet irradiation, adding the low-rank coal and a photocatalyst P25 into a buffer solution, carrying out stirring at a constant temperature of 20 to 90 DEG C until no abundant foam is generated, adding an oxidant in batches in the process of stirring, then carrying out standing and a reaction at a room temperature or a constant temperature for 0.3 to 10 hours, carrying out centrifuging, and subjecting obtained precipitate to concentrating and drying so as to obtain the water-soluble humic acid organic fertilizer. According to the invention, the humic acid organic fertilizer is prepared by extraction with P25 as a photocatalyst and the low-rank coal as a raw material in a buffer system; the extraction rate of hymatomalenic acid and fulvic acid is 55% or above; the extraction rate of fulvic acid is 35% or above; the content of biochemical active groups (such as total acid groups like carboxyl groups, phenolic hydroxyl groups and methoxy groups) is also up to 7.6 mmol / g or above; and the active effect of the biochemical active groups is superior to the active effect of nanometer ZnO.

Description

technical field [0001] The invention relates to a method for producing water-soluble humic acid organic fertilizer by P25 catalytic oxygen decomposition of low-rank coal, which belongs to the technical field of agricultural production. Background technique [0002] Humic acid is the remains of animals and plants, mainly the remains of plants. It is a type of organic substance formed and accumulated through a series of processes of microbial decomposition and transformation, as well as geochemistry. Its structure contains carboxyl, hydroxyl, carbonyl, and quinone groups , methoxy, etc. can complex with metal ions in water, which is conducive to the transfer of nutrients to crops, and can improve the soil structure, thereby promoting the growth of crops. Under normal circumstances, fulvic acid with a smaller molecular weight in humic acid has the advantages of good water solubility and strong permeability, and its application in the agricultural field is more prominent, especi...

AI Technical Summary

Problems solved by technology

There are many ways to produce humic acid from low-rank coal, but the existing production methods are not perfect. Among the extracted products, the molecular weight of humic acid is generally large, and the permeability and water solubility are poor. The reason is that it has a high content of active radicals. The yield of brown yellow humic acid in the group is low

[0003] Chinese patent document CN106810703A discloses a method for preparing humic acid by catalytic oxidation of lignite, the steps are as follows: (1) raw coal drying, (2) pickling, (3) loading catalyst, (4) catalyst form conversion and coal sample oxidation, ( 5) Preparation of humic acid; under the premise of taking into account the production cost, the present invention improves the process of preparing humic acid by catalytic oxidation of lignite, and completes the conversion of catalyst while oxidizing coal, which can significantly improve the yield of humic acid and make humic acid The yield is increased by 18-25%, which increases the added value of lignite, but this method does not improve the situation that the humic acid product has a large molecular weight, poor permeability and water solubility, and the production process is complicated, the cost is high, and the difficulty of industrial production application Larger, not conducive to industrialization

Although this method improves the degradation effect, due to the continuous oxygen decomposition of low-rank coal raw materials, the reaction system turns from neutral to acidic and the acidity continues to increase, reducing the dissolution rate of brown humic acid. Secondly, with the increase of the acidity of the reaction system , the catalyst nano-ZnO is very prone to photodissolution, thereby reducing the catalytic effect

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