CN-122006664-A - Titanium gypsum biochar composite material and preparation method and application thereof

Abstract

The invention relates to the technical field of soil remediation materials, in particular to a titanium gypsum biochar composite material, a preparation method and application thereof. The raw materials of the composite material comprise titanium gypsum and high-silicon biomass, wherein the high-silicon biomass can be rice husk or silicate modified biomass. The preparation method comprises the steps of crushing biomass raw materials, performing alkali washing and reaming, adding the crushed biomass raw materials into sodium silicate solution for soaking, stirring at a constant temperature, taking out and drying to obtain silicate modified biomass, calcining titanium gypsum at a low temperature, adding the calcined titanium gypsum into a reduction inhibitor for soaking, stirring at a constant temperature, taking out, drying and crushing to obtain preactivated titanium gypsum, uniformly mixing the silicate modified biomass and the preactivated titanium gypsum, and calcining at a high temperature under an anaerobic condition. The titanium gypsum biochar composite material can be used as a soil restoration agent, has good fixing capability on soil heavy metals, overcomes the problem of heavy metal regeneration commonly existing in-situ restoration, and realizes long-term restoration of soil.

Inventors

• YAN YUN
• WANG JIANZHONG
• Fan Bangbang
• Shi Yansha

Assignees

• 西昌学院

Dates

Publication Date

20260512

Application Date

20260211

Claims (10)

1. 1. A titanium gypsum biochar composite material is characterized in that the raw materials comprise titanium gypsum and high-silicon biomass.
2. 2. The titanium gypsum biochar composite material of claim 1, wherein the high silicon biomass is rice husk or silicate modified biomass.
3. 3. The method for producing a titanium gypsum biochar composite material according to any one of claims 1 to 2, wherein when the high silicon biomass is a silicate modified biomass, comprising the steps of: S1, crushing a biomass raw material, performing alkali washing and reaming, adding the crushed biomass raw material into a sodium silicate solution for soaking, stirring at a constant temperature, and taking out and drying to obtain silicate modified biomass; S2, calcining the titanium gypsum at a low temperature, then adding the titanium gypsum into a reduction inhibitor for soaking, stirring at a constant temperature, taking out, drying and crushing to obtain preactivated titanium gypsum; And S3, uniformly mixing the silicate modified biomass and the pre-activated titanium gypsum, and calcining at high temperature under the anaerobic condition to obtain the modified biomass.
4. 4. The method for preparing the titanium gypsum biochar composite material according to claim 3, wherein in the step S2, the low-temperature calcination temperature is 180-200 ℃.
5. 5. The method for preparing titanium gypsum biochar composite material according to claim 3, wherein in step S2, the reduction inhibitor is a potassium nitrate solution.
6. 6. The method for preparing the titanium gypsum biochar composite material according to claim 3, wherein the weight ratio of the silicate-modified biomass to the preactivated titanium gypsum is 1:2-4.
7. 7. The method for preparing the titanium gypsum biochar composite material according to claim 3, wherein in the step S2, the high-temperature calcination temperature is 600-650 ℃.
8. 8. The method for preparing a titanium gypsum biochar composite material according to any one of claims 1 to 2, wherein when the high silicon biomass is rice hulls, the method comprises the steps of: Crushing rice hulls, adding the crushed rice hulls into a strong alkali solution, heating and stirring, and taking out and drying to obtain a biomass precursor; t2, calcining the titanium gypsum at a low temperature, then adding the titanium gypsum into a reduction inhibitor for soaking, stirring at a constant temperature, taking out, drying and crushing to obtain preactivated titanium gypsum; and T3, adding the biomass precursor and the pre-activated titanium gypsum into a potassium nitrate solution, mixing and soaking, taking out and filtering, and calcining at high temperature under the anaerobic condition to obtain the titanium gypsum.
9. 9. The application of the titanium gypsum biochar composite material according to any one of claims 1-2, wherein the titanium gypsum biochar composite material is used as a soil heavy metal restoration agent.
10. 10. The application of the titanium gypsum biochar composite material is characterized in that the titanium gypsum biochar composite material is used for repairing cadmium-polluted and lead-polluted soil, and the application method is that the titanium gypsum biochar composite material is spread on the soil surface or is buried after being uniformly mixed with the soil.

Description

Titanium gypsum biochar composite material and preparation method and application thereof Technical Field The invention relates to the technical field of soil restoration materials. In particular to a titanium gypsum biochar composite material and a preparation method and application thereof. Background Titanium gypsum is an industrial byproduct gypsum generated during the production of titanium pigment by a sulfuric acid method, and mainly comprises calcium sulfate dihydrate (CaSO 4·2H2 O), and contains partial iron oxide, so that the titanium gypsum is red, and further contains Si, ti, mg, al and other various impurities. For a long time, titanium gypsum is piled up in a large amount as a solid waste, so that land resource waste is caused, and serious threat is caused to an ecological system, so that the resource utilization and the safe disposal of the titanium gypsum are the problems to be solved urgently. Compared with the common gypsum product, the titanium gypsum has lower content of calcium sulfate and contains a large amount of impurities, so that the comprehensive utilization rate of the titanium gypsum is not high at present, and the titanium gypsum is generally used as a lower substitution product of the common gypsum. However, it has been found that when titanium gypsum is used as a soil restoration agent, a better heavy metal restoration effect can be achieved. For example, "Niu Shiyu. Modification treatment of titanium gypsum and road property research [ D ]. Shandong university of architecture, 2024." indicates that titanium gypsum is hydrolyzed in soil to form Fe (OH) 3 colloid, and the activity of heavy metals in soil is reduced by means of adsorption, chelation, precipitation and the like, so that the repair of heavy metal contaminated soil is realized. "Xu" research on the repair effect of gypsum-based materials on arsenic-lead contaminated soil [ D ]. University of agriculture and forestry in Zhejiang, 2020. "indicates that titanium gypsum can adsorb Cd 2+ by adsorption, coprecipitation and chelation of iron hydroxide colloid. Therefore, the titanium gypsum is expected to be used as an effective soil in-situ passivation repairing agent, and the purpose of treating waste by waste is realized. However, in situ passivation does not reduce the total amount of heavy metals in the soil, but simply converts heavy metal contaminants from an unstable state to a more stable form, and there is still a risk that the heavy metals are re-resolved and further released, causing secondary pollution. The biochar is a product obtained by thermal cracking of biomass energy raw materials, and can fix heavy metals through adsorption due to stable chemical structure and good adsorption performance, and can realize efficient restoration of soil heavy metals by loading metal oxides in pores of the biochar, however, the adsorption mode has poor stability, and long-term risk of heavy metal reactivation caused by environmental change still exists. In the prior art, chinese patent CN202311016305.7 discloses a composite material prepared from titanium gypsum and biochar, wherein the composite material is prepared by physically blending the biochar and the titanium gypsum and has good adsorption effect on heavy metals, and Chinese patent CN202411075373.5 discloses a titanium gypsum biochar composite material for repairing arsenic-polluted soil, which is prepared by mechanically grinding or leaching and mixing biomass raw materials and titanium gypsum and then pyrolyzing the mixture, and can passivate arsenic in the soil. However, the titanium gypsum and the biochar in the composite material are combined in a physical mode, the problem of heavy metal desorption and regeneration still cannot be solved, and the calcium carbonate particles can be dissolved and recrystallized again after meeting water to generate cementing performance, so that soil hardening is caused, and the method has the defect of long-acting restoration. In summary, there is a need to provide a biochar composite material capable of recycling titanium gypsum with high added value, which can realize efficient restoration of heavy metals in soil, avoid hardening of soil caused by high calcium ions, and inhibit regeneration of heavy metals in acidic microenvironment. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a titanium gypsum biochar composite material which is at least used for soil restoration, can avoid soil hardening caused by high calcium ions and can inhibit the regeneration of heavy metals in an acidic microenvironment. The invention aims at realizing the following technical scheme: A titanium gypsum biochar composite material comprises titanium gypsum and high-silicon biomass. In some embodiments, the high silicon biomass is rice hulls or silicate modified biomass. In some examples, when the high silicon biomass is a silicate modified biomass, the method comprises the steps of: S1, crushing a