Composite material used in soil remediation and preparation method thereof

Abstract

The invention relates to a composite material used in soil remediation and a preparation method thereof. The remediation material is a porous compound material with through pores, and formed by crosslinking carboxymethylcellulose or sodium salt components thereof and chitosan with the mass ratio of being 0.5-9.5:1; the average pore size of the pore is 20-200 mum; and the water absorption rate among the pores is 2000 percent to 8000 percent of the self weight of the material. In preparation, the carboxymethylcellulose or the sodium salt components thereof and the chitosan are mixed with water under the condition that pH is 2 to 5 and the temperature is 30 to 60 DEG C so as to form a clear and transparent sol system; then the system is arranged in a molding mold, the temperature is reduced to minus 20 DEG C for fully congealing; and finally the porous composite material is obtained after freeze drying. The porous composite material can be directly inoculated with phosphate-solubilizing bacterium and nitrogen-fixing bacterium, has the functions of water absorption and water maintenance properties and higher density for bearing the microorganisms of phosphate-solubilizing bacterium and/or nitrogen-fixing bacterium and the like, and good biocompatibility and biodegradability; and degradation products have no pollution to the environment, can be recycled for use in ecological environment, and can improve soil structure by mixing with soil so as to absorb and maintain water and enhance the soil fertility.

Description

technical field [0001] The invention relates to an agricultural soil treatment composite material, specifically, a functional composite material with water absorption / water retention function, which can be further loaded with microbial carriers such as phosphorus-dissolving bacteria and nitrogen-fixing bacteria, and a preparation method of the material. Background technique [0002] Super absorbent and water-retaining material is usually a functional polymer material containing strong hydrophilic groups such as carboxyl and hydroxyl groups and has a certain degree of cross-linking. It is insoluble in water, but has high water absorption and water retention capabilities. It has been widely used in Medical and health, agricultural gardens, petrochemical, civil engineering and other fields. For example, Li Li et al reported in "Preparation Process and Performance Evaluation of Natural Polymer Water-absorbing Materials" ("Material Science and Technology" [J]. 2006, 14 (5): 470-4...

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Problems solved by technology

[0007] The content of nitrogen in the atmosphere is close to 80%, but most plants cannot directly absorb and utilize it. Microorganisms such as autogenous nitrogen-fixing bacteria can fix molecular nitrogen in the air and convert it into biological energy through the activity of nitrogenase in the body. The ammoniacal nitrogen directly used by the body is the so-called biological nitrogen fixation. Phosphorus, like nitrogen, plays a key role in the metabolic activities of plants such as energy conversion, respiration and photosynthesis. However, existing studies have shown that The utilization rate of phosphorus fertilizer is only about 20%, and most of the phosphorus is fixed by the soil to form insoluble phosphide. Therefore, increasing the number of nitrogen-fixing microorganisms in the soil and the utilization rate of phosphorus play an important role in plant growth. A lot of research It has been proved that inoculating phosphate-solubilizing bacteria into the soil and using the organic acids produced by its growth and reproduction can decompose insoluble phosphates in the soil and convert them into soluble phosphorus, which can greatly increase the content of available phosphorus in the soil, thereby improving the phosphorus content of crops. Nutrients. Moreover, phosphorus solubilizing bacteria also have a significant promotion effect on the reproduction of nitrogen fixing bacteria and nitrogen fixation activity, and nitrogen fixing bacteria also have key biological effects on the germination of phosphorus solubilizing bacteria and the formation of water-soluble phosphorus. But in practice In the application, due to the lack of effective carriers of these microorganisms in the soil, it is difficult to exert its due and maximum effect and efficacy, and the applied and / or formed fertilizer components are also easily lost with water, making it difficult to improve the soil structure, Increase soil fertility and improve plant nutrition and growth-promoting effects.

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