Preparation method of fertilizer with functions of reducing content of heavy metal ions and achieving sustained release

Abstract

The invention relates to a sustained release fertilizer capable of reducing the content of heavy metal ions in soil and a preparation method thereof. By adopting sodium sulfide, polyvinyl alcohol, aluminum nitrate nonahydrate, magnesium nitrate hexahydrate, lignin and urea as reaction raw materials, the sustained release fertilizer with sulfur-containing hydrotalcite and lignin as carriers is prepared through a reaction. Sulfur ions in the sustained release fertilizer and the heavy metal ions can generate a water-insoluble sulfide precipitate, the effect of reducing the content of the migration-state heavy metal ions in the soil is achieved, and meanwhile a compound composed of sulfur-containing hydrotalcite and lignin has the sustained release function on urea. The dual-functional fertilizer can reduce environmental pollution caused by excessive heavy metal ions in the soil and reduce the cost of soil treatment without affecting normal agricultural production.

Description

Technical field:

[0001] The invention provides a slow-release fertilizer capable of reducing the content of heavy metal ions in soil, and also provides a preparation method of the slow-release fertilizer, belonging to the field of organic-inorganic composite materials. Background technique:

[0002] With the continuous improvement of industrial development and urbanization, land resources are becoming increasingly tight, and today's world is suffering from various environmental problems. Due to the mining and smelting of metal mines, the discharge of industrial and domestic sewage, the application of pesticides and fertilizers containing heavy metals, and sewage irrigation, the problem of heavy metal pollution in soil is becoming more and more serious. According to statistics, the area of ​​soil contaminated by heavy metals in my country is about 2 × 10 7 hm 2 , accounting for about 1 / 6 of the country's total cultivated land area. If such soil is used for agricultural pro...

Examples

Embodiment 1

[0037]Sodium sulfide (0.5 g) and polyvinyl alcohol 400 (50 g) were added to water (500 g) in turn, and stirred for 40 min to mix the compounds uniformly to form solution A.

[0038] Then, aluminum nitrate nonahydrate (2.6g) and magnesium nitrate hexahydrate (3.2g) were added to water (45g) from which carbon dioxide was removed to form a mixed solution. The mixed solution was stirred and adjusted to pH 7.0 with 5wt% NaOH, and the mixed solution was placed at 70 ℃, react under nitrogen protection for 2h, and filter out colloidal substance B.

[0039] Then, the solution A and the filtered colloidal substance B were uniformly mixed at a weight ratio of 1:1, placed at 50 °C, and stirred for 5 h to obtain a colloidal solution C.

[0040] Then, C and lignin were uniformly mixed at a weight ratio of 10:1, placed at 20 °C, and stirred for 1 h to obtain D.

[0041] Finally, D and urea were mixed in a weight ratio of 11:2, placed at 60°C, stirred for 3 hours, dried at 65°C for 10 hours,...

Embodiment 2

[0043] Sodium sulfide (0.8 g) and polyvinyl alcohol 600 (80 g) were added to water (600 g) in turn, and stirred for 40 min to mix the compounds uniformly to form solution A. Then, aluminum nitrate nonahydrate (2.8g) and magnesium nitrate hexahydrate (3.9g) were added to water (50g) from which carbon dioxide was removed to form a mixed solution. The mixed solution was stirred and adjusted to pH 8.0 with 10wt% NaOH, and the mixed solution was placed at 70 ℃, react under nitrogen protection for 10 h, and filter out the colloidal substance B. Then, the solution A and the filtered colloidal substance B were uniformly mixed at a weight ratio of 2:1, placed at 60°C, and stirred for 8 h to obtain a colloidal solution C. Then, C and lignin were uniformly mixed at a weight ratio of 15:1, placed at 50 °C, and stirred for 5 h to obtain D. Finally, D and urea were mixed in a weight ratio of 8:1, placed at 80°C, stirred for 6 hours, dried at 65°C for 10 hours, crushed and sieved, and 10-20...

Embodiment 3

[0045] Sodium sulfide (1.4 g) and polyvinyl alcohol 1000 (40 g) were successively added to water (350 g), and stirred for 10 min to mix the compounds uniformly to form solution A. Then, aluminum nitrate nonahydrate (3.1 g) and magnesium nitrate hexahydrate (3.7 g) were added to water (65 g) from which carbon dioxide was removed to form a mixed solution, and the mixed solution was stirred while adjusting the pH to 7.5 with 15wt% NaOH, and the mixed solution was placed at 75 ℃, react under nitrogen protection for 6 h, and filter out the colloidal substance B. Then, the solution A and the filtered colloidal substance B were uniformly mixed at a weight ratio of 3:1, placed at 55° C., and stirred for 7 h to obtain a colloidal solution C. Then, C and lignin were uniformly mixed at a weight ratio of 35:2, placed at 40 °C, and stirred for 10 h to obtain D. Finally, D and urea were mixed in a weight ratio of 11:4, placed at 25°C, stirred for 1 hour, dried at 65°C for 10 hours, crushed...

Technical field:

[0001] The invention provides a slow-release fertilizer capable of reducing the content of heavy metal ions in soil, and also provides a preparation method of the slow-release fertilizer, belonging to the field of organic-inorganic composite materials. Background technique:

[0002] With the continuous improvement of industrial development and urbanization, land resources are becoming increasingly tight, and today's world is suffering from various environmental problems. Due to the mining and smelting of metal mines, the discharge of industrial and domestic sewage, the application of pesticides and fertilizers containing heavy metals, and sewage irrigation, the problem of heavy metal pollution in soil is becoming more and more serious. According to statistics, the area of ​​soil contaminated by heavy metals in my country is about 2 × 10 7 hm 2 , accounting for about 1 / 6 of the country's total cultivated land area. If such soil is used for agricultural pro...

Examples

Embodiment 1

[0037]Sodium sulfide (0.5 g) and polyvinyl alcohol 400 (50 g) were added to water (500 g) in turn, and stirred for 40 min to mix the compounds uniformly to form solution A.

[0038] Then, aluminum nitrate nonahydrate (2.6g) and magnesium nitrate hexahydrate (3.2g) were added to water (45g) from which carbon dioxide was removed to form a mixed solution. The mixed solution was stirred and adjusted to pH 7.0 with 5wt% NaOH, and the mixed solution was placed at 70 ℃, react under nitrogen protection for 2h, and filter out colloidal substance B.

[0039] Then, the solution A and the filtered colloidal substance B were uniformly mixed at a weight ratio of 1:1, placed at 50 °C, and stirred for 5 h to obtain a colloidal solution C.

[0040] Then, C and lignin were uniformly mixed at a weight ratio of 10:1, placed at 20 °C, and stirred for 1 h to obtain D.

[0041] Finally, D and urea were mixed in a weight ratio of 11:2, placed at 60°C, stirred for 3 hours, dried at 65°C for 10 hours,...

Embodiment 2

[0043] Sodium sulfide (0.8 g) and polyvinyl alcohol 600 (80 g) were added to water (600 g) in turn, and stirred for 40 min to mix the compounds uniformly to form solution A. Then, aluminum nitrate nonahydrate (2.8g) and magnesium nitrate hexahydrate (3.9g) were added to water (50g) from which carbon dioxide was removed to form a mixed solution. The mixed solution was stirred and adjusted to pH 8.0 with 10wt% NaOH, and the mixed solution was placed at 70 ℃, react under nitrogen protection for 10 h, and filter out the colloidal substance B. Then, the solution A and the filtered colloidal substance B were uniformly mixed at a weight ratio of 2:1, placed at 60°C, and stirred for 8 h to obtain a colloidal solution C. Then, C and lignin were uniformly mixed at a weight ratio of 15:1, placed at 50 °C, and stirred for 5 h to obtain D. Finally, D and urea were mixed in a weight ratio of 8:1, placed at 80°C, stirred for 6 hours, dried at 65°C for 10 hours, crushed and sieved, and 10-20...

Embodiment 3

[0045] Sodium sulfide (1.4 g) and polyvinyl alcohol 1000 (40 g) were successively added to water (350 g), and stirred for 10 min to mix the compounds uniformly to form solution A. Then, aluminum nitrate nonahydrate (3.1 g) and magnesium nitrate hexahydrate (3.7 g) were added to water (65 g) from which carbon dioxide was removed to form a mixed solution, and the mixed solution was stirred while adjusting the pH to 7.5 with 15wt% NaOH, and the mixed solution was placed at 75 ℃, react under nitrogen protection for 6 h, and filter out the colloidal substance B. Then, the solution A and the filtered colloidal substance B were uniformly mixed at a weight ratio of 3:1, placed at 55° C., and stirred for 7 h to obtain a colloidal solution C. Then, C and lignin were uniformly mixed at a weight ratio of 35:2, placed at 40 °C, and stirred for 10 h to obtain D. Finally, D and urea were mixed in a weight ratio of 11:4, placed at 25°C, stirred for 1 hour, dried at 65°C for 10 hours, crushed...

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