1. The method for modifying the plastic by utilizing the carbon dioxide product captured by the nanofiltration seawater is characterized by comprising the following steps:

step one, recovering a product, namely micronizing: 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 0.2-1 mm; finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.2-1 mm in a wet grinding mode, wherein the size is 1-100 mu m, and drying the magnesium carbonate and calcium carbonate after wet grinding to prepare a micron-sized magnesium carbonate and calcium carbonate mixture;

step two, preparing modified plastics: mixing and extruding the micron-sized magnesium carbonate and calcium carbonate mixture prepared in the step one, plastic, alkali-soluble polyester, a dispersing agent and an antioxidant in a double-screw extruder according to mass percentage to prepare modified plastic containing alkali-soluble polyester; wherein: 81-96 parts of plastic, 2.4-6.5 parts of a mixture of micron-sized magnesium carbonate and calcium carbonate, 1-10 parts of alkali-soluble polyester, 0.5-2 parts of a dispersant, 0.1-0.7 part of an antioxidant, and 100 parts of total weight;

step three, subsequent treatment: and dissolving the alkali-soluble polyester in the modified plastic containing the alkali-soluble polyester obtained in the step three by using a NaOH solution with the mass concentration of 0.04-1.05%, and then performing conventional separation and drying to obtain the modified plastic.

2. The method of modifying plastics using nanofiltration seawater capture of carbon dioxide product as claimed in claim 1, wherein: the modified plastic has a porosity of 30-95%: the air permeability is 100-1000 s/100ml, and the pore size is 0.2-0.9 μm.

3. The method of modifying plastics using nanofiltration seawater capture of carbon dioxide product as claimed in claim 1, wherein: in the wet grinding mode grinding in the first step, the ball material ratio is as follows: 10-16: 1, wherein the ball material is alumina and/or zirconia, and the ball milling time is as follows: the ball milling temperature is less than 60 ℃ for 6-10 h.

4. The method of modifying plastics using nanofiltration seawater capture of carbon dioxide product 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 on the basis of the treated product wastewater until large flocculent calcium carbonate and magnesium carbonate are formed in the product wastewater containing the carbon dioxide trapped 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.

5. The method of modifying plastics using nanofiltration seawater capture of carbon dioxide product as claimed in claim 4, wherein: the molecular weight of the Anionic Polyacrylamide (APAM) in the step A is 1000-1800 ten thousand.

6. The method of modifying plastics using nanofiltration seawater capture of carbon dioxide product as claimed in claim 4, 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

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 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 utilized to capture carbon dioxide in flue gas, calcium carbonate, magnesium carbonate and the like are obtained, and the recovered calcium carbonate and magnesium carbonate are used as important components of recovered resources to realize carbon dioxide capture and resource utilization.

The recycled calcium carbonate and magnesium carbonate are used as modified filled plastics, and the prepared plastic filler with controllable size and gap distribution has wide market application prospect, and has great potential particularly in the aspects of water purification, battery diaphragm, heat insulation material and the like. Meanwhile, the added value of the carbon dioxide recovery product collected by the nanofiltration seawater can be improved, and the carbon dioxide collection and resource utilization are effectively promoted.

Disclosure of Invention

The invention relates to a method for modifying plastics by using nanofiltration seawater to capture a carbon dioxide product. Firstly, micronizing calcium carbonate and magnesium carbonate which are products of carbon dioxide captured by nanofiltration seawater; and then compounding the plastic, the alkali-soluble polyester, the micron-sized calcium carbonate and magnesium carbonate, the antioxidant and the dispersing agent through a double-screw extruder, and finally dissolving the alkali-soluble polyester by using a sodium hydroxide solution to prepare the porous modified plastic. The invention adopts a double-screw extruder to prepare modified plastics, and because of the introduction of alkali soluble polyester, calcium carbonate and magnesium carbonate are orderly arranged along the alkali soluble polyester. The method of the invention not only can effectively control the gap distribution of the modified plastic, but also can improve the mechanical property of the porous modified plastic.

The method for modifying the plastic by utilizing the carbon dioxide product captured by the nanofiltration seawater is characterized by comprising the following steps:

step one, recovering a product, namely micronizing: 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 0.2-1 mm; finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.2-1 mm in a wet grinding mode, wherein the size is 1-100 mu m, and drying the magnesium carbonate and calcium carbonate after wet grinding to prepare a micron-sized magnesium carbonate and calcium carbonate mixture;

step two, preparing modified plastics: mixing and extruding the micron-sized magnesium carbonate and calcium carbonate mixture prepared in the step one, plastic, alkali-soluble polyester, a dispersing agent and an antioxidant in a double-screw extruder according to mass percentage to prepare modified plastic containing alkali-soluble polyester; wherein: 81-96 parts of plastic, 2.4-6.5 parts of a mixture of micron-sized magnesium carbonate and calcium carbonate, 1-10 parts of alkali-soluble polyester, 0.5-2 parts of a dispersant, 0.1-0.7 part of an antioxidant, and 100 parts of total weight;

step three, subsequent treatment: and dissolving the alkali-soluble polyester in the modified plastic containing the alkali-soluble polyester obtained in the step three by using a NaOH solution with the mass concentration of 0.04-1.05%, and then performing conventional separation and drying to obtain the modified plastic.

The modified plastic has a porosity of 30-95%: the air permeability is 100-1000 s/100ml, and the pore size is 0.2-0.9 μm.

In the wet grinding mode grinding in the first step, the ball material ratio is as follows: 10-16: 1, wherein the ball material is alumina and/or zirconia, and the ball milling time is as follows: the ball milling temperature is less than 60 ℃ for 6-10 h.

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 on the basis of the treated product wastewater until large flocculent calcium carbonate and magnesium carbonate are formed in the product wastewater containing the carbon dioxide trapped 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 invention has the following advantages:

1. the invention adopts a double-screw extruder to prepare micron-sized calcium carbonate and magnesium carbonate modified plastics, and because of the introduction of alkali soluble polyester, the calcium carbonate and the magnesium carbonate are orderly arranged along the alkali soluble polyester in the double-screw extrusion process. The invention not only can effectively control the gap distribution of the modified plastic, but also can improve the mechanical property of the porous modified plastic;

2. the porosity of the ordered porous micron-sized modified plastic of magnesium carbonate and calcium carbonate prepared by the invention is 30-95%: the air permeability is 100-1000 s/100ml, the pore size is 0.2-0.9 mu m, the porous membrane has wide market application prospect, and has great potential particularly in the aspects of water purification, battery membranes, heat insulation materials and the like.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The raw materials of the invention are 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) and 0.05% by mass of sodium methylenedinaphthalene sulfonate NNO by taking the treated product wastewater as a reference, wherein the molecular weight of the Anionic Polyacrylamide (APAM) is 1000 ten thousand 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

First, product micronization was recovered: crushing the recovered products of magnesium carbonate and calcium carbonate of the carbon dioxide trapped by the nanofiltration seawater by a crusher, wherein the crushing size is 1.2 mm; then, grinding by a grinder, wherein the grinding size is 0.25 mm; and finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.25mm by adopting a wet grinding mode to prepare a micron-sized magnesium carbonate and calcium carbonate mixture. Wherein the size of the micron-sized magnesium carbonate and calcium carbonate is 1.5 mu m, the ball-material ratio is 16:1, the ball-milling time is 10 hours, and the ball-milling temperature is 55 ℃; drying the wet-milled magnesium carbonate and calcium carbonate to prepare a micron-sized magnesium carbonate and calcium carbonate mixture.

Next, modified plastic preparation: 2.4 parts of the prepared micron-sized magnesium carbonate and calcium carbonate mixture, 92 parts of plastic, 4.5 parts of alkali-soluble polyester, 0.4 part of barium stearate dispersant and 0.7 part of phosphite antioxidant are co-extruded in a double-screw extruder according to mass percentage to prepare modified plastic containing alkali-soluble polyester;

and finally, carrying out subsequent treatment: and dissolving the alkali-soluble polyester in NaOH solution with the mass concentration of 0.05% to remove the alkali-soluble polyester, and performing conventional separation and drying to obtain the modified plastic with orderly arranged pores. Through detection: porosity of modified plastic 55%: the air permeability is 600 s/100ml, and the pore size is 0.45 mu m.

Example 2

First, product micronization was recovered: crushing the recovered products of magnesium carbonate and calcium carbonate of the carbon dioxide trapped by the nanofiltration seawater by a crusher, wherein the crushing size is 1.2 mm; then, grinding by a grinder, wherein the grinding size is 0.25 mm; and finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.25mm by adopting a wet grinding mode to prepare a micron-sized magnesium carbonate and calcium carbonate mixture. Wherein the size of the micron-sized magnesium carbonate and calcium carbonate is 1.5 mu m, the ball-material ratio is 16:1, the ball-milling time is 10 hours, and the ball-milling temperature is 55 ℃; drying the wet-milled magnesium carbonate and calcium carbonate to prepare a micron-sized magnesium carbonate and calcium carbonate mixture.

Next, modified plastic preparation: mixing 6.5 parts of the prepared micron-sized magnesium carbonate and calcium carbonate mixture, 87.9 parts of plastic, 4.5 parts of alkali-soluble polyester, 0.4 part of barium stearate dispersant and 0.7 part of phosphite antioxidant in a double-screw extruder according to mass percent, and extruding to prepare modified plastic containing alkali-soluble polyester;

and finally, carrying out subsequent treatment: and dissolving the alkali-soluble polyester in NaOH solution with the mass concentration of 0.05% to remove the alkali-soluble polyester, and performing conventional separation and drying to obtain the modified plastic with orderly arranged pores. Through detection: porosity of modified plastic 64%: air permeability 560 s/100ml, pore size 0.58 μm.

Example 3

First, product micronization was recovered: 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 with the grinding size of 1 mm; and finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 1mm in a wet grinding mode to prepare a micron-sized magnesium carbonate and calcium carbonate mixture. Wherein the size of the micron-sized magnesium carbonate and calcium carbonate is 100 mu m, the ball-material ratio is 12:1, the ball-milling time is 8h, and the ball-milling temperature is 40 ℃; drying the wet-milled magnesium carbonate and calcium carbonate to prepare a micron-sized magnesium carbonate and calcium carbonate mixture.

Next, modified plastic preparation: 2.4 parts of the prepared micron-sized magnesium carbonate and calcium carbonate mixture, 96 parts of plastic, 1 part of alkali-soluble polyester, 0.5 part of barium stearate dispersant and 0.1 part of phosphite antioxidant are co-extruded in a double-screw extruder according to mass percentage to prepare modified plastic containing alkali-soluble polyester;

and finally, carrying out subsequent treatment: and dissolving the alkali-soluble polyester in NaOH solution with the mass concentration of 0.05% to remove the alkali-soluble polyester, and performing conventional separation and drying to obtain the modified plastic with orderly arranged pores. Through detection: porosity of modified plastic 35%: air permeability of 130 s/100ml, pore size of 0.21 μm.

Example 4

First, product micronization was recovered: crushing the recovered products of magnesium carbonate and calcium carbonate of the carbon dioxide trapped by the nanofiltration seawater by a crusher, wherein the crushing size is 1.2 mm; then, grinding by a grinder, wherein the grinding size is 0.25 mm; and finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.25mm by adopting a wet grinding mode to prepare a micron-sized magnesium carbonate and calcium carbonate mixture. Wherein the size of the micron-sized magnesium carbonate and calcium carbonate is 1.5 mu m, the ball-material ratio is 16:1, the ball-milling time is 10 hours, and the ball-milling temperature is 55 ℃; drying the wet-milled magnesium carbonate and calcium carbonate to prepare a micron-sized magnesium carbonate and calcium carbonate mixture.

Next, modified plastic preparation: mixing 6.5 parts of the prepared micron-sized magnesium carbonate and calcium carbonate mixture, 81 parts of plastic, 10 parts of alkali-soluble polyester, 2 parts of barium stearate dispersing agent and 0.5 part of phosphite antioxidant in a double-screw extruder according to mass percent, and extruding to prepare modified plastic containing alkali-soluble polyester;

and finally, carrying out subsequent treatment: and dissolving the alkali-soluble polyester in NaOH solution with the mass concentration of 0.05% to remove the alkali-soluble polyester, and performing conventional separation and drying to obtain the modified plastic with orderly arranged pores. Through detection: porosity of modified plastic 67.3%: the air permeability is 349 s/100ml, and the pore size is 0.67 mu m.

Example 5

First, product micronization was recovered: crushing the recovered products of magnesium carbonate and calcium carbonate of the carbon dioxide trapped by the nanofiltration seawater by a crusher, wherein the crushing size is 1 mm; then, grinding by a grinder, wherein the grinding size is 0.2 mm; and finally, grinding the recovered magnesium carbonate and calcium carbonate with the size of 0.2mm by adopting a wet grinding mode to prepare a micron-sized magnesium carbonate and calcium carbonate mixture. Wherein the size of the micron-sized magnesium carbonate and calcium carbonate is 1 mu m, the ball-material ratio is 10:1, the ball-milling time is 6h, and the ball-milling temperature is 45 ℃; drying the wet-milled magnesium carbonate and calcium carbonate to prepare a micron-sized magnesium carbonate and calcium carbonate mixture.

Next, modified plastic preparation: 2.4 parts of the prepared micron-sized magnesium carbonate and calcium carbonate mixture, 96 parts of plastic, 1 part of alkali-soluble polyester, 0.5 part of barium stearate dispersant and 0.1 part of phosphite antioxidant are co-extruded in a double-screw extruder according to mass percentage to prepare modified plastic containing alkali-soluble polyester;

and finally, carrying out subsequent treatment: and dissolving the alkali-soluble polyester in NaOH solution with the mass concentration of 0.04% to remove the alkali-soluble polyester, and performing conventional separation and drying to obtain the modified plastic with orderly arranged pores. Through detection: porosity of modified plastic 57.8%: air permeability 573 s/100ml, pore size 0.31 μm.

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.