Artificial alkaline mineral for promoting ocean convergence increase as well as preparation method and application of artificial alkaline mineral

Abstract

The invention discloses an artificial alkaline mineral for promoting ocean convergence enhancement and a preparation method and application thereof.The preparation method comprises the steps that firstly, a composite oxide wet filter cake is prepared through a coprecipitation method, then the composite oxide wet filter cake and silica gel are mixed, and alkaline mineral solid particles are obtained through high-temperature roasting; and finally, crushing the alkaline mineral solid particles to obtain the artificial alkaline mineral powder. According to the alkaline mineral with high specific surface area and large pore volume, the opportunity of acting with CO2 is increased, so that the carbon storage efficiency of a biological pump is improved, and ocean carbon dioxide convergence increase is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of seawater alkalization and carbon sink enhancement, and specifically relates to an artificial alkaline mineral for promoting ocean carbon sink enhancement, and a preparation method and application thereof. Background Art

[0002] The ocean is the largest active carbon reservoir on Earth, and its carbon dioxide storage accounts for 93% of the Earth's total carbon storage, which is 20 and 50 times the size of terrestrial carbon reservoirs and atmospheric carbon reservoirs, respectively. Therefore, ocean carbon sink enhancement and negative emission technologies have received widespread attention in recent years. The idea of ​​ocean carbon sink enhancement and negative emission technologies is mainly based on the solubility pump, biological pump, microbial carbon pump and carbonate pump mechanisms or their combination to develop corresponding technical methods to increase the production of carbon storage materials such as particulate organic carbon and autogenous carbonates, so that they can be efficiently exported to the deep sea and achieve long-term carbon fixation.

[0003] The alkaline mineral sink enhancement technology mainly uses olivine minerals to add to seawater, utilizing its weathering effect and its regulating effect on the alkalinity of the water body to accelerate the consumption of carbon dioxide in the water body and the generation of bicarbonate, increase the production of autogenous carbonates, and thus improve the ocean's carbon fixation capacity.

[0004] The increased alkalinity from the dissolution of alkaline minerals can be used to repair surface ocean acidification, which is beneficial for maintaining the growth of calcified organisms (such as corals with calcareous shells). In addition, the dissolution of alkaline minerals such as olivine or attapulgite can also generate silica, which is beneficial for the growth of primary producers such as diatoms. The release of trace iron contained in alkaline minerals is also often a nutrient that limits the growth of phytoplankton. Therefore, alkaline mineral weathering can not only increase ocean carbon flux by increasing alkalinity and absorbing more CO2, but also promote phytoplankton growth through the release of silicon and iron, increase the pH value of surface seawater, and stimulate biological pumps and microbial carbon pumps to increase carbon flux and carbon sequestration.

[0005] It is worth noting that alkaline minerals have a limited ability to absorb carbon dioxide due to their small specific surface area, which affects the efficiency of carbon storage. On the other hand, due to the limited ambient water temperature, alkaline minerals have a weak interaction with carbon dioxide, which also affects the carbon storage efficiency. Therefore, increasing the specific surface area and pore volume of alkaline minerals and increasing the probability of interaction with carbon dioxide are key issues to be addressed in improving carbon sinks. Summary of the invention

[0006] The present invention is proposed to improve the carbon storage efficiency and carbon sink capacity of seawater, and its purpose is to provide a preparation method and application of artificial alkaline minerals for promoting ocean carbon sink.

[0007] The present invention is achieved through the following technical solutions:

[0008] A method for preparing an artificial alkaline mineral for promoting marine carbon sinks comprises the following steps:

[0009] (I) preparing a composite oxide wet cake by a coprecipitation method;

[0010] (II) mixing the composite oxide wet filter cake with silica gel and calcining at high temperature to obtain alkaline mineral solid particles;

[0011] (III) crushing alkaline mineral solid particles to obtain alkaline mineral powder.

[0012] In the above technical scheme, the specific operation of the co-precipitation method in step (I) is: first prepare a mixed metal salt solution; then add a precipitant to the mixed metal salt solution, heat and stir to form a precipitate, maintain the pH value of the reaction solution system at 7.0±0.2, and then age, filter and wash to obtain a composite oxide wet cake.

[0013] In the above technical solution, the metal is any two or more of Mg, Ca, Ce, La, Fe or Al; the salt is any one of nitrate, sulfate, chloride or oxalate or a combination of several thereof; the precipitant is any one of sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydroxide, potassium hydroxide or ammonia water.

[0014] In the above technical solution, the concentration of metal ions in the mixed metal salt solution is 0.02 mol / L to 2.0 mol / L; the concentration of the precipitant in the mixed metal salt solution is 0.5 mol / L to 2.5 mol / L.

[0015] In the above technical solution, the coprecipitation reaction time is 0.5h to 2h, the temperature is 60°C to 120°C; the aging temperature is 60°C to 120°C, and the aging time is 4h to 12h.

[0016] In the above technical solution, the specific surface area of ​​the silica gel in step (II) is 300m 2 / g~550m 2 / g, pore volume is 1.0cm 3 / g~1.5cm 3 / g, pore size is 15nm to 20nm; the mass ratio of the composite oxide wet filter cake to the silica gel is 9:1 to 5:5 。

[0017] In the above technical solution, the temperature of the high temperature calcination in step (II) is 800-1200° C., and the duration of the high temperature calcination is 4h-6h.

[0018] In the above technical solution, the average particle size of the alkaline mineral powder in step (III) is 20 μm to 50 μm.

[0019] An artificial alkaline mineral for promoting ocean sink is prepared by the above method.

[0020] An application of artificial alkaline minerals for promoting ocean carbon sink in seawater enclosures. The specific method of carbon sink is: artificially adding alkaline mineral powder into seawater enclosures.

[0021] In the above technical solution, the calculation formula for the dosage of the alkaline mineral powder is:

[0022] m=η×(A×H) / τ

[0023] Where: m is the amount of alkaline mineral powder added, in kg; η is the feed mass ratio, dimensionless, η = 0.03% ~ 3%; τ is the seawater residence time, in h; A is the area of ​​the enclosed sea area, in m 2 ; H is the average water depth, in meters.

[0024] An application of an artificial alkaline mineral for promoting carbon sink enhancement in the evaluation of the carbon sink enhancement capacity of a seawater enclosure. The specific method for evaluating the carbon sink enhancement capacity is: artificially adding alkaline mineral powder into a seawater enclosure, measuring evaluation parameters of the sea area where the carbon sink enhancement is implemented, and evaluating the carbon sink enhancement capacity.

[0025] In the above technical solution, the evaluation parameters include the pH value of the enclosed seawater, the partial pressure of carbon dioxide (PCO2), the concentration of inorganic nutrient salts and the total organic carbon.

[0026] The beneficial effects of the present invention are:

[0027] The present invention provides an artificial alkaline mineral for promoting ocean carbon sink, and a preparation method and application thereof. The method has simple steps, and the raw materials are readily available. The ocean carbon sink is combined with the carbon dioxide mineralization technology to improve the carbon fixation rate and increase the carbon sink capacity. The present invention prepares an artificial alkaline mineral rich in alkaline earth metal oxides, rare earth metal oxides, iron oxides, aluminum oxide or silicon oxide by a coprecipitation method, which is low in cost. The artificial alkaline mineral is crushed and added to seawater to accelerate the absorption of carbon dioxide. The weakly alkaline material can not only alleviate ocean acidification, but also does not affect the marine ecological environment. It can also promote the synergistic effect of four mechanisms of solubility pump, biological carbon pump, microbial carbon pump and carbonate pump in seawater, thereby improving the carbon storage efficiency and carbon sink capacity of seawater, increasing the amount of carbon sink, and realizing the increase of ocean carbon dioxide sink. DETAILED DESCRIPTION

[0028] In order to enable persons skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below through specific implementation methods.

[0029] Embodiment 1:

[0030] A method for increasing the sink of artificial alkaline minerals in the coastal waters of the Yellow Sea (Aoshan Bay, Qingdao) in late spring (May). The experimental steps are as follows:

[0031] (I) Preparation of composite metal oxide wet cake by coprecipitation method

[0032] Add 100 mL of deionized water to a beaker, dissolve 10.26 g of magnesium nitrate hexahydrate, 10.42 g of cerium nitrate hexahydrate, 8.08 g of ferric nitrate nonahydrate and 31.95 g of hydrated aluminum nitrate in the beaker, prepare a mixed metal salt solution, heat the mixed metal salt solution to 80° C., then dropwise add a 1.5 mol / L ammonium carbonate solution to the mixed metal salt solution, stir vigorously, keep the pH value of the precipitation solution at 7.0, age for 6 hours, filter and wash, and finally obtain a wet cake of the composite metal oxide;

[0033] (II) The wet cake of the composite oxide obtained above was mixed with 50 g of a 2 / g, pore volume 1.2cm 3 / g, and silica gel with a pore size of 18nm, and calcined at 1000°C to obtain alkaline mineral solid particles, which were then crushed to obtain alkaline mineral powder with an average particle size of 30μm;

[0034] (III) The coastal waters of Aoshan Bay, Qingdao in May (salinity of 32.53) were used as the experimental water body. The alkaline mineral powder obtained was artificially added into the seawater enclosure at a mass ratio of 0.1% of the alkaline minerals to the seawater in the selected sea area, and artificial waves were used for flushing with a flushing period of 1.0 s to evaluate the carbon sink capacity.

[0035] Embodiment 2:

[0036] A method for increasing the carbon sequestration by placing artificial alkaline minerals in the coastal waters of the Yellow Sea (Aoshan Bay, Qingdao) in late spring (May), which is different from Example 1 in that:

[0037] In step (I), the mixed metal salt is replaced with 10.26 g of magnesium nitrate hexahydrate, 8.08 g of ferric nitrate nonahydrate and 31.95 g of hydrated aluminum nitrate are dissolved in a beaker, and 100 mL of deionized water is used to prepare a mixed metal salt solution.

[0038] Embodiment 3:

[0039] A method for increasing the carbon sequestration by placing artificial alkaline minerals in the coastal waters of the Yellow Sea (Aoshan Bay, Qingdao) in late spring (May), which is different from Example 1 in that:

[0040] In step (I), the mixed metal salt is replaced with 10.26 g of magnesium nitrate hexahydrate and 31.95 g of hydrated aluminum nitrate, which are dissolved in a beaker, and 100 mL of deionized water is used to prepare a mixed solution.

[0041] Embodiment 4:

[0042] A method for increasing the sink of artificial alkaline minerals in the coastal oligotrophic seawater (salinity of 35.47) in summer (July) in the South China Sea (Haitang Bay, Sanya), the experimental steps are as follows:

[0043] (I) Preparation of composite metal oxide wet cake by coprecipitation method

[0044] Add 100 mL of deionized water into a beaker and dissolve 10.26 g of magnesium nitrate hexahydrate, 10.42 g of cerium nitrate hexahydrate and 31.95 g of hydrated aluminum nitrate in the beaker to prepare a mixed metal salt solution, then heat the mixed metal salt solution to 80° C., then drop 1.5 mol / L of ammonium carbonate solution into the mixed metal salt solution, stir vigorously, keep the end point pH value of the precipitation solution at 7.0, age for 6 hours, filter and wash, and finally obtain a wet cake of the composite metal oxide;

[0045] (II) The wet cake of the composite oxide obtained above was mixed with 50 g of a 2 / g, pore volume 1.2cm 3 / g, and silica gel with a pore size of 18nm, and calcined at 1000°C to obtain alkaline mineral solid particles, which were then crushed to obtain alkaline mineral powder with an average particle size of 30μm;

[0046] (III) The oligotrophic seawater (salinity of 35.47) in Haitang Bay, Sanya in July was used as the experimental water body. The alkaline mineral powder obtained was artificially added into the seawater enclosure at a mass ratio of 0.1% of the alkaline mineral to the seawater. Artificial waves were used for flushing with a flushing period of 1.0 s to evaluate the carbon sink capacity.

[0047] Embodiment 5:

[0048] A method for increasing the sink by placing artificial alkaline minerals in the coastal oligotrophic seawater (salinity of 35.47) in the summer (July) of the South China Sea (Haitang Bay, Sanya), which is different from Example 4 in that:

[0049] In step (III), the alkaline mineral powder obtained is artificially added into the seawater enclosure at a mass ratio of 0.5% of the alkaline mineral to the seawater, and artificial waves are used for flushing with a flushing period of 1.0 s to evaluate the sink enhancement capacity.

[0050] Embodiment 6:

[0051] A method for increasing the sink by placing artificial alkaline minerals in the coastal oligotrophic seawater (salinity of 35.47) in the summer (July) of the South China Sea (Haitang Bay, Sanya), which is different from Example 4 in that:

[0052] In step (II), the alkaline mineral powder obtained is artificially added into the seawater enclosure at a mass ratio of 1% of the alkaline mineral to the seawater, and artificial waves are used for flushing with a flushing period of 1.0 s to evaluate the sink enhancement capacity.

[0053] Comparative Example 1:

[0054] The seawater without mixed minerals added near the Yellow Sea (Aoshan Bay, Qingdao) was used for artificial wave flushing with a flushing period of 1.0s to evaluate the seawater sink capacity.

[0055] Comparative Example 2:

[0056] The seawater without mixed minerals added near the coast of the South China Sea (Haitang Bay, Sanya) was used for artificial wave flushing with a flushing period of 1.0s to evaluate the seawater sinking capacity of the enclosed seawater.

[0057] The pH value, alkalinity, carbon dioxide partial pressure, nutrient concentration, and total organic carbon of the experimental water bodies of Examples 1 to 6 and Comparative Examples 1 and 2 after 10 days of action were measured to evaluate the sink capacity of the enclosed seawater. The comparative data are shown in Table 1.

[0058] Table 1: Comparison of the sink capacity of enclosed seawater in different experimental water bodies during the same action time

[0059]

[0060]

[0061] By comparing the above embodiments with the comparative examples, it can be seen that the present invention is simple, easy to implement, and has low cost. It combines marine carbon sink with carbon dioxide mineralization technology to carry out research and development of marine alkaline mineral carbon fixation technology, thereby improving the carbon fixation rate and increasing the carbon sink capacity. It can also alleviate ocean acidification and is conducive to industrial promotion.

[0062] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing an artificial alkaline mineral for promoting ocean sinks, characterized in that: The following steps are involved: (I) preparing a composite oxide wet cake by a coprecipitation method; (II) mixing the composite oxide wet filter cake with silica gel and calcining at high temperature to obtain alkaline mineral solid particles; (III) crushing alkaline mineral solid particles to obtain alkaline mineral powder.

2. The method for preparing an artificial alkaline mineral for promoting marine carbon sink according to claim 1, characterized in that: The specific operation of the coprecipitation method in step (I) is as follows: first, a mixed metal salt solution is prepared; then, a precipitant is added to the mixed metal salt solution, heated and stirred to carry out a coprecipitation reaction, the pH value of the reaction solution system is maintained at 7.0±0.2, and then aged, filtered and washed to obtain a composite oxide wet cake.

3. The method for preparing an artificial alkaline mineral for promoting marine carbon sink according to claim 2, characterized in that: The metal is any two or more of Mg, Ca, Ce, La, Fe or Al; the salt is any one of nitrate, sulfate, chloride or oxalate or a combination of several thereof; the precipitant is any one of sodium carbonate, potassium carbonate, ammonium carbonate, sodium hydroxide, potassium hydroxide or ammonia water.

4. The method for preparing an artificial alkaline mineral for promoting marine carbon sink according to claim 2, characterized in that: The concentration of metal ions in the mixed metal salt solution is 0.02 mol / L to 2.0 mol / L; the concentration of the precipitant is 0.5 mol / L to 2.5 mol / L.

5. The method for preparing an artificial alkaline mineral for promoting ocean sink according to claim 2, characterized in that: The coprecipitation reaction time is 0.5h to 2h; the aging temperature is 60°C to 120°C, and the aging time is 4h to 12h.

6. The method for preparing an artificial alkaline mineral for promoting ocean sink according to claim 1, characterized in that: The specific surface area of ​​the silica gel in step (II) is 300 m 2 / g~550m 2 / g, pore volume is 1.0cm 3 / g~1.5cm 3 / g, the pore size is 15nm-20nm; the mass ratio of the composite oxide wet filter cake to the silica gel is 9:1-5:5; The temperature of the high temperature calcination is 800° C. to 1200° C., and the duration of the high temperature calcination is 4 h to 6 h.

7. The method for preparing an artificial alkaline mineral for promoting ocean sink according to claim 1, characterized in that: The average particle size of the alkaline mineral powder in step (III) is 20 μm to 50 μm.

8. An artificial alkaline mineral for promoting ocean sinks, characterized in that: Prepared by the method according to any one of claims 1 to 7.

9. An application of an artificial alkaline mineral for promoting ocean carbon sink prepared by the method according to any one of claims 1 to 7 in seawater carbon sink enhancement, characterized in that: The specific method of carbon storage and sink enhancement is: artificially adding alkaline mineral powder into the seawater enclosure; the calculation formula of the addition amount of the alkaline mineral powder is: m=η×(A×H) / τ Where: m is the amount of alkaline mineral powder added, in kg; η is the feed mass ratio, dimensionless, η = 0.03% ~ 3%; τ is the seawater residence time, in h; A is the area of ​​the enclosed sea area, in m 2 ; H is the average water depth, in meters.

10. An application of an artificial alkaline mineral for promoting ocean carbon sink prepared by the method of any one of claims 1 to 7 in the evaluation of seawater carbon sink capacity, characterized in that: The specific method for evaluating the carbon storage and sink capacity is: artificially adding alkaline mineral powder into the seawater enclosure, measuring the evaluation parameters of the sea area where the sink is implemented, and evaluating the sink capacity; the evaluation parameters include the pH of the enclosure seawater, the partial pressure of carbon dioxide, the concentration of inorganic nutrient salts and the total organic carbon.

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