Titanium-based compound conditioner for arsenic-cadmium-lead compound polluted soil as well as preparation method and application of titanium-based compound conditioner
By using a compound conditioner made from desulfurized gypsum and potassium titanium oxalate, the problem of simultaneous passivation of soil contaminated with arsenic, cadmium, and lead in paddy fields was solved, achieving effective fixation of heavy metals and safe crop production, and reducing the accumulation of heavy metals in crops.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTH CHINA AGRICULTURAL UNIVERSITY
- Filing Date
- 2026-01-12
- Publication Date
- 2026-04-21
AI Technical Summary
Existing technologies are insufficient to effectively immobilize arsenic, cadmium, and lead simultaneously in paddy fields, leading to the toxic threat of heavy metal contaminated soil to crops. Furthermore, traditional remediation materials may adversely affect soil properties and plant growth, especially in redox environments where they are ineffective.
A titanium-based compound conditioner, made by combining desulfurized gypsum and potassium titanium oxalate, is prepared by preparing microsphere wet materials, drying and pulverizing them to form a titanium-based compound conditioner for soils contaminated with arsenic, cadmium and lead. This conditioner is then applied to paddy fields to reduce the migration and bioavailability of heavy metals.
It achieves simultaneous passivation of arsenic, cadmium, and lead in an alternating redox environment, reducing the heavy metal content in the edible parts of crops, increasing crop biomass, and converting heavy metal forms into non-utilizable components, thus meeting safety standards.
Smart Images
Figure CN121892496A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical passivation of heavy metals in soil, and particularly to a titanium-based compound conditioner for soil contaminated with arsenic, cadmium, and lead, its preparation method, and its application. Background Technology
[0002] Heavy metal contamination of agricultural soils has become a global problem, attracting worldwide attention due to its severe adverse effects on agricultural ecosystems and human health. Cadmium (Cd), arsenic (As), and lead (Pb) are frequently found in soils simultaneously, and these have been identified as the most common heavy metals in agricultural production, threatening human health due to their high toxicity, bioaccumulation, and non-degradability. Therefore, the remediation of heavy metal-contaminated farmland soils is urgently needed. Given its time-saving, cost-effectiveness, ease of operation, and minimal disruption, the use of immobilization materials to reduce the mobility and bioavailability of heavy metals in soil is a preferred option.
[0003] Because As and Cd, Pb exhibit different biogeochemical behaviors in soil, achieving in-situ fixation of both remains a challenge. Against this backdrop, current methods primarily involve adding one or more of the following materials: compounds of sulfur, manganese, iron, and calcium; industrial solid wastes such as red mud, fly ash, coal gangue, and gypsum; and agricultural wastes such as biochar, organic fertilizer, and corn stalks. These methods typically add large amounts of materials (>5%), which may adversely affect soil properties and plant growth. Furthermore, most methods target only specific heavy metals, with few capable of simultaneously fixing both anions and cations. Simultaneously, in the alternating wet and dry redox cycles of paddy fields, the environmental behaviors of As and Cd, Pb exhibit opposite transformation patterns due to microbial activity. During flooding, iron reduction dominates, leading to the release and activation of As from the solid phase; while sulfate reduction promotes the formation of sulfide precipitates for Cd and Pb fixation. After drainage and oxidation, the fixation of As and the activation of Cd and Pb reverse again. This contradictory dynamic process poses a significant challenge to simultaneous remediation. Therefore, preparing compound materials that can simultaneously fix As, Cd, and Pb in redox alternating paddy fields to achieve safe crop production is a major challenge.
[0004] Therefore, there is an urgent need for a soil conditioner that can simultaneously and effectively reduce the accumulation of As, Cd, and Pb in crops in farmland with compound pollution. Summary of the Invention
[0005] The primary objective of this invention is to provide a titanium-based compound conditioner for soils contaminated with arsenic, cadmium, and lead. This titanium-based compound conditioner can effectively passivate the bioavailability of heavy metals, reduce the toxicity of heavy metals to plants, and effectively remediate heavy metal-contaminated soil, with better results than single passivating agents.
[0006] Another object of the present invention is to provide a method for preparing the above-mentioned titanium-based compound conditioner for soil contaminated with arsenic, cadmium and lead.
[0007] Another object of the present invention is to provide the application of the above-mentioned titanium-based compound conditioner for soil contaminated with arsenic, cadmium and lead.
[0008] To achieve the objective of this invention, the following technical solution is adopted: a titanium-based compound conditioner for soil contaminated with arsenic, cadmium and lead, wherein the active ingredients are obtained by compounding desulfurized gypsum and potassium titanium oxalate in a mass ratio of 2-3:0.672.
[0009] The preparation method of the above-mentioned titanium-based compound conditioner for arsenic, cadmium, and lead co-contaminated soil includes the following steps:
[0010] (1) Dry the desulfurized gypsum to constant weight, grind it, and sieve it to obtain desulfurized gypsum powder;
[0011] (2) Dissolve potassium titanium oxalate in water to obtain potassium titanium oxalate solution;
[0012] (3) Desulfurized gypsum powder is mixed with atomized potassium titanium oxalate solution under stirring to obtain microsphere wet material;
[0013] (4) Dry the wet microsphere material to constant weight, crush it, and sieve it to obtain a titanium-based compound conditioner for soil contaminated with arsenic, cadmium and lead.
[0014] The drying method described in step (1) is preferably blower drying.
[0015] The drying temperature in step (1) is preferably 100-110 °C; more preferably 105 °C.
[0016] The sieve mentioned in step (1) is preferably a 200-mesh sieve.
[0017] The concentration of the potassium titanium oxalate solution in step (2) is preferably 1.5 to 2.5 mol / L; more preferably 2 mol / L.
[0018] The preferred stirring speed in step (3) is as follows: 150-250 rpm when adding potassium titanium oxalate solution, and 500-700 rpm after adding potassium titanium oxalate solution; more preferably, 200 rpm when adding potassium titanium oxalate solution, and 600 rpm after adding potassium titanium oxalate solution.
[0019] The atomized potassium titanium oxalate solution described in step (3) is preferably obtained using a two-fluid spray head.
[0020] The drying method described in step (4) is preferably blower drying.
[0021] The drying temperature in step (4) is preferably 85-95 °C; more preferably 90 °C.
[0022] The sieve mentioned in step (4) is preferably a 100-mesh sieve.
[0023] The above-mentioned titanium-based compound conditioner for arsenic, cadmium, and lead contaminated soil is used in the remediation of arsenic, cadmium, and lead contaminated soil.
[0024] The dosage of the titanium-based compound conditioner for soil contaminated with arsenic, cadmium, and lead is 0.25 to 1% of the soil mass.
[0025] The above-mentioned titanium-based compound conditioner for soil contaminated with arsenic, cadmium, and lead is applied in plant cultivation.
[0026] The dosage of the titanium-based compound conditioner for soil contaminated with arsenic, cadmium, and lead is 0.25 to 1% of the soil mass.
[0027] The plants mentioned include vegetables and rice.
[0028] The preferred vegetable is lettuce.
[0029] The present invention has the following advantages and effects compared with the prior art:
[0030] (1) The present invention uses a conditioning agent composed of desulfurized gypsum and potassium titanium oxalate to achieve simultaneous passivation of As, Cd and Pb.
[0031] (2) The present invention reduces the content of As, Cd and Pb in the edible part of lettuce by combining desulfurized gypsum and potassium titanium oxalate, so that the content of Cd and Pb is lower than the national safety threshold.
[0032] (3) The passivating agent provided by the present invention can transform the forms of As, Cd and Pb in the soil from bioavailable components to difficult-to-use components in a pot experiment of paddy soil with moderate to mild As, Cd and Pb combined pollution, thereby increasing the biomass of various parts of rice and reducing the accumulation of As, Cd and Pb in rice grains. Attached Figure Description
[0033] Figure 1 This is a graph showing the results of determining the available As, Cd, and Pb contents in the soil under different material blending ratios.
[0034] Figure 2This is a graph showing the distribution of As, Cd, and Pb components in the rhizosphere soil of rice. Among them, in the arsenic speciation distribution, F1 is non-specifically adsorbed arsenic, F2 is specifically adsorbed arsenic, F3 is amorphous iron-aluminum oxide bound arsenic, F4 is crystalline iron-aluminum oxide bound arsenic, and F5 is residual arsenic. In the cadmium / lead speciation distribution, F1 is ion-exchangeable cadmium / lead, F2 is carbonate bound cadmium / lead, F3 is iron-manganese oxide bound cadmium / lead, F4 is organic matter and sulfide bound cadmium / lead, and F5 is residual cadmium / lead.
[0035] Figure 3 This is a graph showing the results of measurements on root, straw, and grain biomass during the rice maturity stage.
[0036] Figure 4 This is a graph showing the results of the determination of As, Cd, and Pb content in the roots of rice at maturity.
[0037] Figure 5 This is a graph showing the results of the determination of As, Cd, and Pb content in rice straw at the ripening stage.
[0038] Figure 6 This is a graph showing the results of the determination of As, Cd, and Pb content in rice grains at maturity. Detailed Implementation
[0039] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.
[0040] Example 1
[0041] (1) Experimental methods
[0042] The tested soil was taken from Jiaoxi Township, Liuyang City, Changsha City, Hunan Province. The soil contained 30.299 mg / kg of arsenic, 2.152 mg / kg of cadmium, and 140.387 mg / kg of lead.
[0043] Test materials: potassium titanium oxalate, desulfurized gypsum.
[0044] 1) Dry the commercially available desulfurized gypsum to constant weight in a forced-air drying oven at 105℃, so that its moisture content is less than 0.5%, grind it through a 200-mesh sieve, and obtain desulfurized gypsum powder with a median particle size D50 of 65±10 μm for later use.
[0045] 2) Use a planetary ball mill (add 100g at a time, revolution speed of 300 rpm, rotation speed to revolution speed ratio of 1:2, ball-to-material ratio of 5:1, intermittent operation for 1 hour) to grind commercially available potassium titanium oxalate into micro powder with D50 less than 30 μm, and set aside for later use.
[0046] 3) Dissolve potassium titanium oxalate in deionized water at room temperature (20-30℃) to prepare a clear, transparent solution with a concentration of 2 mol / L (672 g / L). Add desulfurized gypsum to a high-speed shear mixer and granulator at 200 r / min according to different solid-liquid ratios (g:mL), such as 1:1, 2:1, 3:1, 4:1, and 5:1. Spray the potassium titanium oxalate solution through a two-fluid spray head, atomizing it evenly and slowly. After spraying, increase the speed to 600 r / min and continue running for 10 minutes to obtain wet microspheres with a particle size between 0.5-2 mm.
[0047] 4) Transfer the wet microsphere material to a blower dryer and dry at 90±5℃ for 6-8 hours. Turn the material over every hour during the drying process until the material reaches a constant weight. After drying, crush the material in a pulverizer and pass it through a 100-mesh sieve to remove residual lumps, thus obtaining the titanium-based compound conditioner.
[0048] 100 grams of soil were weighed into containers, and the prepared titanium-based compound conditioner was added at a mass ratio of 1%, followed by the addition of ultrapure water and stirring until homogeneous. Water was added until the soil reached 70% of its field capacity, and the total weight was recorded. Ultrapure water was periodically added to maintain this total weight. A control group was set up without any passivation material, and each treatment group had four replicates. Soil passivation was performed for 49 days. On day 49, soil samples were taken and sieved through a 2 mm sieve for analysis of the passivation effects on As, Cd, and Pb.
[0049] 2. Experimental Results
[0050] To evaluate the passivation effect of this compound conditioner on As, Cd, and Pb in soil, we collected samples after 49 days and analyzed the contents of available As, Cd, and Pb in the soil. Available Cd and Pb in the soil were extracted using diethylenetriaminepentaacetic acid (DTPA) (GB / T 23739-2009), and available As was extracted using NH4H2PO4 (GB / T 44741-2024). The concentrations of As, Cd, and Pb in the extracts were determined using inductively coupled plasma mass spectrometry (ICP-MS) (HJ700-2014). Results Figure 1 As shown. After 49 days of passivation, the passivation effect was best when the solid-liquid ratio of the compound conditioner was 3:1, which reduced the content of available As in the soil by 0.337 mg / kg, the content of available Cd by 0.365 mg / kg, and the content of available Pb by 12.353 mg / kg, respectively.
[0051] Example 2
[0052] (1) Experimental methods
[0053] The tested soil was taken from Jiaoxi Township, Liuyang City, Changsha City, Hunan Province. The soil contained 30.299 mg / kg of arsenic, 2.152 mg / kg of cadmium, and 140.387 mg / kg of lead.
[0054] Test materials: Potassium titanium oxalate powder (KTO) prepared according to steps (1) 2) of Example 1, desulfurized gypsum (FGD) prepared according to steps (1) 1) of Example 1, and phosphogypsum powder (PG) prepared by the same method, potassium titanium oxalate and desulfurized gypsum compound conditioner (FGT) prepared according to Example 1 at a solid-liquid ratio of 3:1 and potassium titanium oxalate and phosphogypsum compound conditioner (PGT) prepared at a solid-liquid ratio of 3:1, and potassium titanium oxalate / desulfurized gypsum compound conditioner (FGT) obtained by directly mixing the two according to the amount of each component in FGT or PGT. M ) and potassium titanium oxalate / phosphogypsum compound conditioner (PGT) M ).
[0055] 100 grams of soil were weighed into separate containers. The following were added at a mass ratio of 1% each: potassium titanium oxalate powder (KTO), desulfurized gypsum (FGD), phosphogypsum (PG), a compound conditioner (FGT) prepared at a solid-liquid ratio of 3:1 (KTO and FGD), a compound conditioner (PGT) prepared at a solid-liquid ratio of 3:1 (PGT), and a composite material (FGTM) and a composite material (PGTM) made by directly mixing the two at the same mass ratio. Ultrapure water was added and stirred until homogeneous. Water was added to 70% of the soil's field capacity, and the total weight was recorded. Ultrapure water was periodically added to maintain this total weight. A control group (CK) was set up without any passivation material. Each treatment group had four replicates. Soil passivation was performed for 49 days. Soil samples were taken after 49 days and sieved through a 2 mm sieve for analysis of the passivation effects on As, Cd, and Pb.
[0056] 2. Experimental Results
[0057] To evaluate the passivation effect of this compound conditioner on soil As, Cd, and Pb, we collected samples after 49 days and analyzed the contents of available As, Cd, and Pb in the soil. Available Cd and Pb in the soil were extracted using diethylenetriaminepentaacetic acid (DTPA) (GB / T 23739-2009), and available As was extracted using NH4H2PO4 (GB / T 44741-2024). The concentrations of As, Cd, and Pb in the extracts were determined using inductively coupled plasma mass spectrometry (ICP-MS) (HJ700-2014). The results are shown in Table 1. The compound conditioner prepared from potassium titanium oxalate and desulfurized gypsum reduced the contents of available As, Cd, and Pb in the soil by 13.93%, 38.23%, and 45.67%, respectively, which was superior to the compound conditioner prepared from potassium titanium oxalate and phosphogypsum. Furthermore, this preparation method was also superior to the compound conditioner prepared by direct mixing.
[0058] Table 1. Effects of different materials on available As, Cd, and Pb in soil
[0059]
[0060] Note: Different letters in the treatment groups and CK indicate significant differences.
[0061] Example 3
[0062] (1) Experimental methods
[0063] The tested soil was taken from Tangxin Village, Xinjiang Town, Shaoguan City, Guangdong Province. The soil contained 137.332 mg / kg of arsenic, 1.836 mg / kg of cadmium, and 91.541 mg / kg of lead.
[0064] Test materials: potassium titanium oxalate powder prepared according to steps (1) and (2) of the example, desulfurized gypsum powder prepared according to steps (1) and (1) of the example, and titanium-based compound conditioner prepared according to Example 1 at a solid-liquid ratio of 3:1.
[0065] 1.5 kg of soil was weighed into flowerpots. Different materials were added to the soil at a mass ratio of 1%, and ultrapure water was added and stirred evenly. Water was added until the soil reached 70% of its field water holding capacity, and the total weight was recorded. Ultrapure water was added periodically to maintain this total weight. One week after the materials were added to the soil and stabilized, lettuce seedlings of uniform size and growth were planted into the pots and cultivated for 35 days, during which water management and fertilization were carried out according to conventional agricultural practices. Four treatments were set up: a control group (without any passivation materials), potassium titanium oxalate, desulfurized gypsum, and titanium-based compound conditioner. The mass amount of materials used in each treatment was the same, and three replicates were set up. After the treatment, soil samples were taken and sieved through a 2 mm sieve to analyze the passivation effect of As, Cd, and Pb. At the same time, the above-ground parts of lettuce were collected, dried to constant weight, and then ground into powder using a pulverizer.
[0066] (2) Experimental results
[0067] To evaluate the passivation effect of this compound conditioner on As, Cd, and Pb in soil, samples were taken after 35 days for analysis of their available content. According to "GB / T 23739-2009 Determination of Available Lead and Cadmium in Soil", diethylenetriaminepentaacetic acid (DTPA) was used to extract available Cd and Pb from the soil; according to "GB / T 44741-2024 Determination of Available Arsenic in Soil from Agricultural Production Areas", NH4H2PO4 was used to extract available As from the soil. According to HJ700-2014, inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the concentrations of As, Cd, and Pb in the extracts. The results are shown in Table 2 below. The passivation material composed of desulfurized gypsum and potassium titanium oxalate can simultaneously passivate As, Cd, and Pb in the soil, and its overall effect is better than that of a single treatment.
[0068] To evaluate the effect of the compound conditioner on the accumulation of As, Cd, and Pb in the edible parts of lettuce, wet digestion (GB 5009.12-2017) was used to digest the edible parts of lettuce, and the concentrations of As, Cd, and Pb in the digestate were determined by ICP-MS. Each batch of digested samples contained a blank sample and a spinach component analysis standard (GBW10015), and the recovery rate of the samples was 96.33±12.09%. The results in Table 2 show that the compound conditioner significantly reduced the As, Cd, and Pb contents in the edible parts of lettuce by 61.84%, 85.84%, and 83.74%, respectively. The Cd and Pb contents in lettuce leaves were below the national safety thresholds for leafy vegetables (0.2 and 0.3 mg / kg, GB 2762-2025).
[0069] Table 2. Effects of different material combinations on the contents of available As, Cd, and Pb in soil and the accumulation of As, Cd, and Pb in usable parts of lettuce.
[0070]
[0071] Example 4
[0072] (1) Test methods
[0073] The titanium-based compound conditioner (prepared by mixing desulfurized gypsum and potassium titanium oxalate solution at a solid-liquid ratio of 3:1) prepared according to Example 1 was used in a rice pot experiment. The tested rice variety was Huanghuazhan (a medium-early maturing indica rice widely cultivated in South China). 5 kg of test soil (soil taken from Jiaoxi Township, Liuyang City, Changsha City, Hunan Province, with arsenic content of 30.299 mg / kg, cadmium content of 2.152 mg / kg, and lead content of 140.387 mg / kg) was accurately weighed, and three rice plants were planted in each pot, one plant per hole. The compound conditioner was applied at proportions of 0.25%, 0.5%, and 1% of soil weight. A control group without any passivation material was set up, and each treatment group had four replicates. After application, the soil was allowed to equilibrate for 7 days at 70% of its field capacity. Rice was then planted for 130 days, during which water management and fertilization were carried out according to conventional agricultural practices.
[0074] 2. Test Results
[0075] To evaluate the effects of this compound conditioner on the basic physicochemical properties and heavy metal speciation of soil, soil rhizosphere samples were sieved through a 2 mm sieve after rice harvest. As speciation was extracted using the Wenzel five-step extraction method (Wenzel WW, Kirchbaumer N, Prohaska T, et al. Arsenic fractionation in soils using an improved sequential extraction procedure[J]. Analytica Chimica Acta, 2001, 436(2):309-323.); Cd and Pb speciation were extracted using the Tessier five-step extraction method (Tessier AP, Campbell P GC, Bisson M X. Sequential extraction procedure for the speciation of particulate trace metals[J]. Analytical chemistry, 1979, 51(7):844-851.). The concentrations of As, Cd, and Pb in the extracts were determined by ICP-MS (HJ700-2014).
[0076] like Figure 2As shown, compared with the control (CK) treatment, the application of the compound conditioner transformed the soil As (As) forms from non-specifically adsorbed, specifically adsorbed, and amorphous iron-aluminum oxide bound states to crystalline iron-aluminum oxide bound states and residual states. With increasing application of the compound conditioner, the contents of non-specifically adsorbed, specifically adsorbed, and amorphous iron-aluminum oxide bound As decreased to the lowest levels of 0.121, 5.848, and 14.833 mg / kg, respectively. Meanwhile, the soil Cd and Pb components gradually transformed from exchangeable, carbonate-bound, and iron-manganese oxide-bound states to organic matter and sulfide-bound states and residual states. At a concentration of 0.5% (w / w) of the compound conditioner, the proportions of residual Cd and Pb components were the lowest, at 14.64% and 41.05%, respectively. At this concentration, the contents of organic matter and sulfide-bound Cd and Pb increased by 0.53% and 1.33%, respectively, compared to the control (CK).
[0077] To evaluate the effects of this compound conditioner on rice growth and heavy metal accumulation, biomass was measured in various parts of the rice after harvest. Simultaneously, wet digestion (GB 5009.12-2017) was used to digest different parts of the rice, and the concentrations of As, Cd, and Pb in the digest were determined by ICP-MS. Each batch of digested samples contained a blank sample and a spinach component analysis standard (GBW10015). The recovery rate was 101.57 ± 7.12%.
[0078] Figure 3 The results showed that, compared with the control (CK), the application of different concentrations of compound conditioner significantly increased the root / straw biomass and grain yield of rice. The biomass of each part of the rice plant was the highest when the compound conditioner was applied at a concentration of 0.5% w / w, with increases of 29.163, 82.373 and 32.918 g, respectively.
[0079] Figure 4-6 The results showed that the contents of As, Cd, and Pb in all parts of rice decreased with increasing application of the compound conditioner. There were no significant differences in the As, Cd, and Pb contents of rice roots, straw, and grains under 0.5% w / w and 1% w / w compound conditioner application. Compared with the control (CK), the Pb content in rice grains decreased from 0.913 mg / kg to 0.198 mg / kg under 0.5% w / w compound conditioner application, which is below the national rice safety threshold (0.2 mg / kg, GB 2762-2025). At the 1% w / w application rate, the As content in rice grains decreased by 1.860 mg / kg to 0.417 mg / kg, which is also below the national rice safety threshold (0.5 mg / kg, GB 2762-2025).
[0080] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A titanium-based compound conditioner for soil contaminated with arsenic, cadmium, and lead, characterized in that: The active ingredient of the titanium-based compound conditioner for soil contaminated with arsenic, cadmium, and lead is obtained by compounding desulfurized gypsum and potassium titanium oxalate in a mass ratio of 2-3:0.
672.
2. The method for preparing the titanium-based compound conditioner for arsenic, cadmium, and lead co-contaminated soil as described in claim 1, characterized in that... Includes the following steps: (1) Dry the desulfurized gypsum to constant weight, grind it, and sieve it to obtain desulfurized gypsum powder; (2) Dissolve potassium titanium oxalate in water to obtain potassium titanium oxalate solution; (3) Desulfurized gypsum powder is mixed with atomized potassium titanium oxalate solution under stirring to obtain microsphere wet material; (4) Dry the wet microsphere material to constant weight, crush it, and sieve it to obtain a titanium-based compound conditioner for soil contaminated with arsenic, cadmium and lead.
3. The method for preparing the titanium-based compound conditioner for arsenic, cadmium, and lead co-contaminated soil according to claim 2, characterized in that: The drying method described in step (1) is blower drying; The drying method described in step (4) is blower drying.
4. The method for preparing the titanium-based compound conditioner for arsenic, cadmium, and lead co-contaminated soil according to claim 3, characterized in that: The drying temperature described in step (1) is 100–110 °C; The drying temperature described in step (4) is 85–95 °C.
5. The method for preparing the titanium-based compound conditioner for arsenic, cadmium, and lead co-contaminated soil according to claim 2, characterized in that: The sieve mentioned in step (1) is a 200-mesh sieve; The sieve mentioned in step (4) is a 100-mesh sieve.
6. The method for preparing the titanium-based compound conditioner for arsenic, cadmium, and lead co-contaminated soil according to claim 2, characterized in that: The concentration of the potassium titanium oxalate solution mentioned in step (2) is 1.5 to 2.5 mol / L.
7. The method for preparing the titanium-based compound conditioner for arsenic, cadmium, and lead co-contaminated soil according to claim 2, characterized in that: The stirring speed in step (3) is as follows: 150-250 rpm when adding potassium titanium oxalate solution, and 500-700 rpm after adding potassium titanium oxalate solution.
8. The application of the titanium-based compound conditioner for arsenic-cadmium-lead co-contaminated soil as described in claim 1 in the remediation of arsenic-cadmium-lead co-contaminated soil.
9. The application of the titanium-based compound conditioner for arsenic, cadmium, and lead contaminated soil as described in claim 1 in plant cultivation.
10. The application according to claim 9, characterized in that: The plants mentioned include vegetables and rice.