1. The method for preparing the soil loosening agent by using the nanofiltration seawater to capture the carbon dioxide product is characterized by comprising the following steps of:

step one, recovering a product for nanocrystallization: crushing recovered products magnesium carbonate and calcium carbonate of carbon dioxide trapped by nanofiltration seawater by using a crusher, wherein the crushing size is 1-10 mm; then, grinding by a grinder, wherein the size is 0.02-0.1 mm; finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.02-0.1 mm in a wet grinding mode, wherein the size is 50-100 nm, and drying the magnesium carbonate and calcium carbonate after wet grinding to prepare a nano-scale magnesium carbonate and calcium carbonate mixture;

step two, preparing a soil loosening agent: uniformly stirring and mixing the nanoscale magnesium carbonate and calcium carbonate mixture prepared in the step one, polyacrylamide PAM, naphthalene sulfonate, organic matters and water according to mass percentage, wherein the stirring time is 5-10h, and the rotating speed is 1000-2000r/min, so as to prepare the soil loosening agent; wherein: 10.5-18.5 parts of a mixture of nano magnesium carbonate and calcium carbonate, 0.05-0.5 part of PAM, 0.1-0.5 part of naphthalene sulfonate, 5.5-10.5 parts of organic matter and 70-83.85 parts of water, wherein the total weight is 100 parts.

2. The method for preparing a soil loosening agent by capturing carbon dioxide product using nanofiltration seawater as claimed in claim 1, wherein: the molecular weight of the Polyacrylamide (PAM) is 800-1100 ten thousand.

3. The method for preparing a soil loosening agent by capturing carbon dioxide product using nanofiltration seawater as claimed in claim 1, wherein: the organic matter is derived from kitchen garbage and/or agricultural straws.

4. The method for preparing a soil loosening agent by capturing carbon dioxide product using nanofiltration seawater as claimed in claim 1, wherein: in the wet grinding mode grinding in the first step, the ball material ratio is as follows: 20-26: 1, wherein the ball material is alumina and/or zirconia, and the ball milling time is as follows: 4-5 h, and the ball milling temperature is less than 60 ℃.

5. The method for preparing a soil loosening agent by capturing carbon dioxide product using nanofiltration seawater as claimed in claim 1, wherein: the recycling products of magnesium carbonate and calcium carbonate for trapping carbon dioxide by nanofiltration seawater are obtained by the following method: step A, settling the product wastewater containing the carbon dioxide captured by the nanofiltration seawater, and specifically comprising the following steps: adding sodium carbonate or potassium carbonate to adjust the pH value of the wastewater to 7-9, continuously adding 0.05-2% of basic polyaluminum chloride by mass fraction, 0.5-100 ppm of Anionic Polyacrylamide (APAM) by mass fraction and 0.05-0.1% of sodium methylenedinaphthalene sulfonate (NNO) by mass fraction based on the treated product wastewater until large flocculent calcium carbonate and magnesium carbonate are formed in the product wastewater containing the carbon dioxide captured by the nanofiltration seawater, reducing the temperature of the product wastewater to 5-10 ℃, accelerating the sedimentation of the calcium carbonate and the magnesium carbonate, discharging the waste water of the precipitated calcium carbonate and the magnesium carbonate into a concentration tank through a pipeline, and drying the calcium carbonate and the magnesium carbonate by a filter press to obtain blocky calcium carbonate and magnesium carbonate; step B, cutting into blocks: c, mechanically cutting the blocky calcium carbonate and magnesium carbonate obtained in the step A into blocks, and then crushing the blocky calcium carbonate and magnesium carbonate into small blocky magnesium carbonate and calcium carbonate by adopting a crusher; and step C, drying: and D, conveying the small blocky magnesium carbonate and calcium carbonate obtained in the step C to a thermal infrared drying heating cavity through a material conveying system for thermal infrared drying and drying to obtain nanofiltration seawater capture carbon dioxide products calcium carbonate and magnesium carbonate.

6. The method for preparing a soil loosening agent by capturing carbon dioxide product using nanofiltration seawater as claimed in claim 5, wherein: the molecular weight of the Anionic Polyacrylamide (APAM) in the step A is 1000-1800 ten thousand.

7. The method for preparing a soil loosening agent by capturing carbon dioxide product using nanofiltration seawater as claimed in claim 5, wherein: and C, the residence time of the small blocky magnesium carbonate and the small blocky calcium carbonate in the thermal infrared drying heating cavity in the step C is 0.1-0.5 h, and the moisture content of the dried magnesium carbonate and the dried calcium carbonate is 0.5-5%.

Background

Climate change is one of the most important survival and development problems facing mankind in this century, and in order to avoid irreversible adverse effects caused by climate systems, effective measures must be taken to reduce and control the generation and emission of greenhouse gases.

China is the country with the largest global carbon dioxide emission, and accounts for about 27% of the total world emission. Data display in 2017: 361 hundred million tons of carbon dioxide are discharged globally; 98.39 hundred million tons of carbon dioxide are discharged all year round in China, and account for 27.2 percent; 52.67 million tons of carbon dioxide are discharged all year round in the United states, 14.6%; india emits 24.67 hundred million tons of carbon dioxide all year round, 6.8%.

Coal is the main reason for carbon dioxide emission in China, and the contribution rate reaches 73%. Data in 2018: china discharges 100 million tons of carbon dioxide, coal contributes 73 million tons, petroleum contributes 15 million tons, cement contributes 7 million tons, and natural gas contributes 5 million tons.

The salinization of soil is a worldwide problem, the area of the saline-alkali soil is about 10 hundred million hectares all over the world, and 9913 million hectares in China are about 14.7 hundred million acres. In addition, China also has a continental coastline which is 18000 kilometers long, and coasts such as Bohai sea, yellow sea and east sea coastal plain, and large areas of coastal saline-alkali soil mainly containing chloride are distributed. Saline-alkali soil is a resource which is not utilized by about 80 percent in China, and the development of large-area saline wasteland and the prevention and treatment of salinization of soil in irrigation areas are important ways for solving the problem of 16 hundred million people of China in the 21 st century. Especially in arid and semiarid regions in China, has extremely important significance for agricultural production development, homeland governance, ecological environment protection and the like.

The control of greenhouse gases is the key development and development direction of future Chinese development, the novel CCUS (carbon capture, utilization and sequestration) technology can effectively solve the problem, high-concentration calcium and magnesium ions in seawater are used for capturing carbon dioxide in smoke to obtain calcium carbonate, magnesium carbonate and the like, the calcium carbonate and the magnesium carbonate are recycled as important components of recycled resources, the recycled calcium carbonate and the magnesium carbonate are applied to the preparation of a soil loosening agent aiming at soil salinization, and the soil loosening agent rich in calcium, magnesium and organic matters can improve the soil structure, increase the soil air permeability, supplement the organic matters, increase the soil activity, play a positive role in the soil salinization, and finally realize the carbon dioxide capture and the resource utilization.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a method for preparing a soil loosening agent by utilizing a nanofiltration seawater to collect a carbon dioxide product, calcium carbonate and magnesium carbonate of the nanofiltration seawater to collect the carbon dioxide product are used as important components of a recovery resource, so that the carbon dioxide collection and resource utilization are realized, the soil loosening agent rich in calcium, magnesium and organic matters is prepared, the soil structure can be improved, the soil air permeability is increased, the organic matters are supplemented, the soil activity is increased, and the positive effect on soil salinization is achieved; meanwhile, the soil loosening agent prepared by the invention is liquid, has long shelf life, is suitable for intelligent irrigation and is convenient to apply. The soil loosening agent can thoroughly improve soil, so that the soil loosening agent can be used for intelligent agricultural production or intelligent management of urban greening.

The method for preparing the soil loosening agent by using the nanofiltration seawater to capture the carbon dioxide product is characterized by comprising the following steps of:

step one, recovering a product for nanocrystallization: crushing recovered products magnesium carbonate and calcium carbonate of carbon dioxide trapped by nanofiltration seawater by using a crusher, wherein the crushing size is 1-10 mm; then, grinding by a grinder, wherein the size is 0.02-0.1 mm; finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.02-0.1 mm in a wet grinding mode, wherein the size is 50-100 nm, and drying the magnesium carbonate and calcium carbonate after wet grinding to prepare a nano-scale magnesium carbonate and calcium carbonate mixture;

step two, preparing a soil loosening agent: uniformly stirring and mixing the nanoscale magnesium carbonate and calcium carbonate mixture prepared in the step one, polyacrylamide PAM, naphthalene sulfonate, organic matters and water according to mass percentage, wherein the stirring time is 5-10h, and the rotating speed is 1000-2000r/min, so as to prepare the soil loosening agent; wherein: 10.5-18.5 parts of a mixture of nano magnesium carbonate and calcium carbonate, 0.05-0.5 part of PAM, 0.1-0.5 part of naphthalene sulfonate, 5.5-10.5 parts of organic matter and 70-83.85 parts of water, wherein the total weight is 100 parts.

The molecular weight of the Polyacrylamide (PAM) is 800-1100 ten thousand.

The organic matter is derived from kitchen garbage and/or agricultural straws.

In the wet grinding mode grinding in the first step, the ball material ratio is as follows: 20-26: 1, wherein the ball material is alumina and/or zirconia, and the ball milling time is as follows: 4-5 h, and the ball milling temperature is less than 60 ℃.

The recycling products of magnesium carbonate and calcium carbonate for trapping carbon dioxide by nanofiltration seawater are obtained by the following method: step A, settling the product wastewater containing the carbon dioxide captured by the nanofiltration seawater, and specifically comprising the following steps: adding sodium carbonate or potassium carbonate to adjust the pH value of the wastewater to 7-9, continuously adding 0.05-2% of basic polyaluminum chloride by mass fraction, 0.5-100 ppm of Anionic Polyacrylamide (APAM) by mass fraction and 0.05-0.1% of sodium methylenedinaphthalene sulfonate (NNO) by mass fraction based on the treated product wastewater until large flocculent calcium carbonate and magnesium carbonate are formed in the product wastewater containing the carbon dioxide captured by the nanofiltration seawater, reducing the temperature of the product wastewater to 5-10 ℃, accelerating the sedimentation of the calcium carbonate and the magnesium carbonate, discharging the waste water of the precipitated calcium carbonate and the magnesium carbonate into a concentration tank through a pipeline, and drying the calcium carbonate and the magnesium carbonate by a filter press to obtain blocky calcium carbonate and magnesium carbonate; step B, cutting into blocks: c, mechanically cutting the blocky calcium carbonate and magnesium carbonate obtained in the step A into blocks, and then crushing the blocky calcium carbonate and magnesium carbonate into small blocky magnesium carbonate and calcium carbonate by adopting a crusher; and step C, drying: and D, conveying the small blocky magnesium carbonate and calcium carbonate obtained in the step C to a thermal infrared drying heating cavity through a material conveying system for thermal infrared drying and drying to obtain nanofiltration seawater capture carbon dioxide products calcium carbonate and magnesium carbonate.

The molecular weight of the Anionic Polyacrylamide (APAM) in the step A is 1000-1800 ten thousand.

And C, the residence time of the small blocky magnesium carbonate and the small blocky calcium carbonate in the thermal infrared drying heating cavity in the step C is 0.1-0.5 h, and the moisture content of the dried magnesium carbonate and the dried calcium carbonate is 0.5-5%.

Due to the adoption of the technical scheme, the method has the following advantages:

1. the soil loosening agent rich in calcium, magnesium and organic matters prepared by the invention can improve the soil structure, increase the soil air permeability, supplement organic matters and increase the soil activity; meanwhile, the soil loosening agent prepared by the invention is liquid, has long shelf life and is convenient to apply. On the premise of not changing soil, saline-alkali soil can be thoroughly improved, so that the saline-alkali soil can be used for intelligent agricultural production or intelligent management of urban landscaping;

2. according to the soil loosening agent prepared by the invention, the nanoscale calcium carbonate and magnesium carbonate can effectively activate soil due to the size effect and the synergistic effect of the nanoscale calcium carbonate and magnesium carbonate, and meanwhile, due to the introduction of organic matters, formed cations such as calcium, magnesium and the like can easily form a bond bridge with soil colloid, so that the rapid formation of a granular structure is promoted, and the water retention, fertilizer retention, air permeability and buffering capacity of the soil are improved and repaired;

3. the soil loosening agent prepared by the invention can directly remove water in soil by nano-scale calcium carbonate and magnesium carbonate in a liquid spraying or drip irrigation mode, and can be absorbed by crops more easily due to small size, so that the phenomena of yellowing and bitter pox caused by the lack of calcium, magnesium and other elements can be effectively prevented.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The raw materials of the embodiments of the invention are all purchased directly.

The recycling products of magnesium carbonate and calcium carbonate for trapping carbon dioxide by the nanofiltration seawater used in the embodiments of the invention are obtained by the following method: step A, settling the product wastewater containing the carbon dioxide captured by the nanofiltration seawater, and specifically comprising the following steps: adding sodium carbonate or potassium carbonate to adjust the pH value of the wastewater to 8.5, continuously adding 1% by mass of basic polyaluminum chloride, 0.5ppm of Anionic Polyacrylamide (APAM), 0.05% by mass of sodium methylenedinaphthalene sulfonate (NNO) and 1000 ten thousand by mass of the Anionic Polyacrylamide (APAM) based on the treated product wastewater until large flakes of flocculent calcium carbonate and magnesium carbonate are formed in the product wastewater containing the nanofiltration seawater trapped carbon dioxide, reducing the temperature of the product wastewater to 6.5 ℃, accelerating the sedimentation of the calcium carbonate and the magnesium carbonate, discharging the waste water of the precipitated calcium carbonate and the magnesium carbonate into a concentration tank through a pipeline, and drying the calcium carbonate and the magnesium carbonate by a filter press to obtain blocky calcium carbonate and magnesium carbonate; step B, cutting into blocks: c, mechanically cutting the blocky calcium carbonate and magnesium carbonate obtained in the step A into blocks, and then crushing the blocky calcium carbonate and magnesium carbonate into small blocky magnesium carbonate and calcium carbonate by adopting a crusher; and step C, drying: and D, conveying the small-block magnesium carbonate and calcium carbonate obtained in the step C to a thermal infrared drying heating cavity through a material conveying system for thermal infrared drying and drying, and keeping for 20 min. And detecting to obtain nanofiltration seawater trapping carbon dioxide products of calcium carbonate and magnesium carbonate, wherein the water content of the nanofiltration seawater trapping carbon dioxide products is 0.42%.

Example 1

Firstly, recovering a product for nanocrystallization: crushing the recovered products of the carbon dioxide trapped by the nanofiltration seawater, namely magnesium carbonate and calcium carbonate by using a crusher, wherein the crushing size is 1.2 mm; then, grinding by a grinder, wherein the grinding size is 0.03 mm; finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.03mm in a wet grinding mode, wherein the size of the nanoscale magnesium carbonate and calcium carbonate is 55nm, the ball-material ratio is 26:1, the ball material is alumina, the ball-milling time is 5 hours, and the ball-milling temperature is 55 ℃; drying the wet-milled magnesium carbonate and calcium carbonate to prepare a nano-scale magnesium carbonate and calcium carbonate mixture.

Then, preparing the soil loosening agent: and uniformly stirring and mixing 10.5 parts of the prepared nano-scale magnesium carbonate and calcium carbonate mixture, 0.05 part of PAM, 0.1 part of sodium naphthalenesulfonate, 5.5 parts of organic matter and 83.85 parts of water according to mass percentage, wherein the molecular weight of Polyacrylamide (PAM) is 800 ten thousand, the organic matter is derived from kitchen garbage, stirring at a high speed for 8 hours and the rotating speed is 1000r/min, and thus obtaining the high-activity soil loosening agent. After observation and detection, the product is placed for 18 months without layering and precipitation.

Example 2

Firstly, recovering a product for nanocrystallization: crushing the recovered products of the carbon dioxide trapped by the nanofiltration seawater, namely magnesium carbonate and calcium carbonate by using a crusher, wherein the crushing size is 1.2 mm; then, grinding by a grinder, wherein the grinding size is 0.03 mm; finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.03mm in a wet grinding mode, wherein the size of the nanoscale magnesium carbonate and calcium carbonate is 55nm, the ball-material ratio is 26:1, the ball material is alumina, the ball-milling time is 5 hours, and the ball-milling temperature is 55 ℃; drying the wet-milled magnesium carbonate and calcium carbonate to prepare a nano-scale magnesium carbonate and calcium carbonate mixture.

Then, preparing the soil loosening agent: and uniformly stirring and mixing 13.9 parts of the prepared nano-scale magnesium carbonate and calcium carbonate mixture, 0.5 part of PAM, 0.5 part of sodium naphthalenesulfonate, 10.5 parts of organic matter and 74.6 parts of water according to mass percentage, wherein the molecular weight of Polyacrylamide (PAM) is 1100 ten thousand, the organic matter is derived from agricultural straws, stirring at a high speed for 10 hours and at a rotating speed of 1350r/min, and thus obtaining the high-activity soil loosening agent. After observation and detection, the product is placed for 13 months without layering and precipitation.

Example 3

Firstly, recovering a product for nanocrystallization: crushing the recovered products of the carbon dioxide trapped by the nanofiltration seawater, namely magnesium carbonate and calcium carbonate by using a crusher, wherein the crushing size is 1.2 mm; then, grinding by a grinder, wherein the grinding size is 0.02 mm; finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.02mm in a wet grinding mode, wherein the size of the nano-scale magnesium carbonate and calcium carbonate is 50nm, the ball-material ratio is 20:1, the ball-milling time is 4h, and the ball-milling temperature is 55 ℃; drying the wet-milled magnesium carbonate and calcium carbonate to prepare a nano-scale magnesium carbonate and calcium carbonate mixture.

Then, preparing the soil loosening agent: and uniformly stirring and mixing 18.5 parts of the prepared nano-scale magnesium carbonate and calcium carbonate mixture, 0.5 part of PAM, 0.5 part of sodium naphthalenesulfonate, 10.5 parts of organic matter and 70 parts of water according to mass percentage, wherein the molecular weight of Polyacrylamide (PAM) is 1000 thousands, the organic matter is prepared from kitchen garbage and agricultural straws by uniformly mixing according to the ratio of 1:1, stirring at a high speed for 10 hours, and rotating at the speed of 1350r/min to prepare the high-activity soil loosening agent. After observation and detection, the product is placed for 13 months without layering and precipitation.

Example 4

Firstly, recovering a product for nanocrystallization: crushing the recovered products of the carbon dioxide trapped by the nanofiltration seawater, namely magnesium carbonate and calcium carbonate by using a crusher, wherein the crushing size is 10 mm; then, grinding by a grinder, wherein the grinding size is 0.1 mm; finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.1mm in a wet grinding mode, wherein the size of the nano-scale magnesium carbonate and calcium carbonate is 100nm, the ball-material ratio is 22:1, the ball-milling time is 5h, and the ball-milling temperature is 45 ℃; drying the wet-milled magnesium carbonate and calcium carbonate to prepare a nano-scale magnesium carbonate and calcium carbonate mixture.

Then, preparing the soil loosening agent: and uniformly stirring and mixing 10.5 parts of the prepared nano-scale magnesium carbonate and calcium carbonate mixture, 0.2 part of PAM, 0.4 part of sodium naphthalenesulfonate, 8.5 parts of organic matter and 80.4 parts of water according to mass percentage, wherein the molecular weight of Polyacrylamide (PAM) is 900 ten thousand, the organic matter is prepared from kitchen garbage and agricultural straws and is uniformly mixed according to the ratio of 1:1, stirring at a high speed for 5 hours and rotating at the speed of 2000r/min, and thus obtaining the high-activity soil loosening agent. After observation and detection, the product is placed for 15 months without layering and precipitation.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.