A water purification concrete and a method for producing the same

Abstract

The application discloses a kind of water purification concrete, each component and the weight fraction it includes: cementitious material 30-55 parts, aggregate 65-95 parts, composite slurry 10-20 parts, air entraining agent 0.003-0.01 parts, water reducing agent 0.4-0.8 parts, mixing water 10-15 parts;The cementitious material includes γ-dicalcium silicate, slag and steel slag;The composite slurry is the mixed solution of chitosan and nanometer titanium dioxide.The water purification concrete in the application can significantly improve the water purification efficiency, realize self-cleaning, avoid concrete pore blockage, greatly extend the water permeability and water purification capacity of water purification concrete, has important economic and environmental benefits, and is suitable for popularization and application.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of building materials, and particularly relates to a water purification concrete and a preparation method thereof. BACKGROUND

[0002] With the increase of human social activities, environmental pollution and ecological destruction problems are becoming increasingly serious. Pollution and destruction of the atmosphere, water bodies and soil have seriously affected the ecological balance and hindered industrial development. In order to cope with the increasingly serious problems of environmental pollution and ecological destruction, in recent years, many experts and scholars have developed environmentally friendly ecological concrete, which combines concrete with ecological management. Research on improving the natural environment through ecological concrete such as vegetation and pervious concrete has been reported many times. The development and implementation of carbon dioxide capture and storage and utilization technology (CCUS) in concrete is also becoming a research hotspot.

[0003] Existing researches are mostly focused on reducing the alkalinity in the vegetation concrete by carbon dioxide curing to increase the strength, so as to make it reach the pH value suitable for plant growth, and adding solid waste in the vegetation concrete to achieve green environmental protection benefits. Patent CN115321904 provides a low-carbon vegetation concrete, which uses carbon dioxide curing to prepare vegetation concrete with low calcium carbonized cement, which can effectively reduce the alkalinity of vegetation concrete and greatly reduce the carbon footprint of concrete from both cementing materials and curing methods. Patent CN117105605 discloses a red mud vegetation concrete based on CO2 curing, which mixes industrial solid waste red mud into vegetation concrete and cures it with carbon dioxide to achieve low alkalinity and solid waste utilization. Patent CN117069467 discloses an alkali-free vegetation concrete, which uses steel slag, desulfurization gypsum and river and lake sludge to prepare vegetation concrete, and adds liquid carbon dioxide for stirring to achieve rapid carbonization and prepare alkali-free vegetation concrete; it has the advantages of no sintering, low cost, extremely low carbon emissions and ultra-low alkali content. However, the above technical solutions mainly use carbon dioxide to cure vegetation concrete to make it reach the low-alkali environment required for plant growth, and achieve the resource utilization of solid waste. However, for polluted water in the environment, the above vegetation concrete can only rely on its own pores to simply physically adsorb water, and cannot further purify complex polluted water.

[0004] Pollutants produced in production and life enter the urban water cycle with the scouring and absorption of rainwater. Part of the polluted rainwater can directly enter the sewage treatment plant through the drainage pipe, but another part of the polluted rainwater is easy to gather in streets, rivers, lakes and other places, causing water pollution and affecting plant growth. It is of great research and application significance to further develop vegetation concrete with strong purification capacity and high efficiency. SUMMARY

[0005] The main purpose of the present application is to solve the problem of limited water purification performance of existing vegetation concrete, and provide a water purification concrete, which uses a low-carbon preparation process to reduce the alkalinity of the concrete while effectively improving the removal capacity of total nitrogen (TN), total phosphorus (TP), organic matter and heavy metal ions and other pollutants through physical and chemical dual action; and can continuously degrade and purify pollutants under sunlight, avoiding pore blockage, realizing green, low-carbon, environmentally friendly and recyclable water purification concrete, having important economic and environmental benefits, and being suitable for popularization and application.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0007] A water purification concrete, the components and the weight percentage thereof include: cementitious material 30-55 parts, aggregate 65-95 parts, composite slurry 10-20 parts, air entraining agent 0.003-0.01 parts, water reducing agent 0.4-0.8 parts, and mixing water 10-15 parts; the cementitious material includes γ-dicalcium silicate, slag and steel slag; and the composite slurry is a mixture of chitosan and nano titanium dioxide.

[0008] According to the above scheme, in the cementitious material, the mass ratio of γ-dicalcium silicate, slag and steel slag is 1:(0.2-0.8):(0.2-0.8), and the specific surface area of the mixture after powder grinding is 300-500 m 2 / kg. In the cementitious material, compared with the traditional portland clinker, γ-dicalcium silicate has a lower calcium-silicon ratio and a lower sintering temperature, and during sintering and cooling, it will self-pulverize due to crystal transformation, which can significantly reduce the grinding energy consumption after kiln discharge, so it consumes less limestone and energy during production, and emits less carbon dioxide; at the same time, it has carbonation activity, absorbs and solidifies carbon dioxide during curing and obtains strength. The hydration capacity of γ-dicalcium silicate is weak, and the addition of slag in the cementitious material can play the alkali-activated activity of the slag under the synergistic action of γ-dicalcium silicate, thereby improving the early stripping strength of the system. The steel slag has high carbonation activity on one hand, and on the other hand, the Ca 2+ and iron oxides contained in the steel slag can adsorb phosphorus through chemical precipitation and ligand exchange, thereby realizing water purification function.

[0009] According to the above scheme, the aggregate is a lightweight porous aggregate with a particle size of 10-15 mm, a cylinder compressive strength of not less than 3 MPa, a bulk density of 600-900 kg / m 3 , and a water absorption rate of 5-20%. By using its porous characteristics, it is used as a carrier of the composite slurry, and at the same time, the adsorbability of the porous aggregate is used to purify wastewater, and the concrete unit weight can be reduced.

[0010] Preferably, the aggregate is one or more of natural zeolite, shale ceramsite and sludge ceramsite, and the water absorption rate is 5-10%. + 2+ The cations such as NH4+, Pb2+ and the like can be physically adsorbed and ion exchanged, and the purification effect is better.

[0011] According to the above scheme, the composite slurry is composed of a slurry with a concentration of 4-6 wt% of chitosan and nano-titanium dioxide, wherein the mass ratio of chitosan to nano-titanium dioxide is 1:(1-2), the nano-titanium dioxide is anatase type, and the particle size is 10-20 nm. The chitosan molecular skeleton contains a large number of -NH2 and -OH, which can chelate most heavy metal ions, and can adsorb heavy metal ions in wastewater. In addition, the complex bond of chitosan can weaken the phase separation between silica gel and calcium carbonate in the carbonization product, so that the connection between the phase interfaces is more compact, and the carbonization performance is effectively enhanced. The anatase type nano-titanium dioxide can produce high-activity photo-generated electron-hole pairs under photocatalysis, which can oxidize and reduce organic pollutants to make the pollutants degrade into environmentally friendly H2O and CO2, etc., realizing self-cleaning. The polarity of Ti-O bond in titanium dioxide is large, and the water adsorbed on the surface is dissociated due to polarization, which is easy to form -OH. The active groups of chitosan after dissolving in water form hydrogen bond with the -OH on the surface of titanium dioxide, which improves the surface structure properties of titanium dioxide and cooperates with the adsorption and purification capacity of chitosan, effectively enhancing the photocatalytic degradation performance of titanium dioxide.

[0012] According to the above scheme, the air entraining agent is at least one of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and triterpene saponin. The air entraining agent can introduce small bubbles into the slurry. On the one hand, the diffusion channel of CO2 gas during carbonation curing is expanded, and the carbonation efficiency is improved. On the other hand, the small pores in the carbonated concrete increase, which facilitates the release of the composite slurry loaded in the aggregate and the photocatalysis. At the same time, by controlling the stirring time, the appropriate small bubbles produced by the air entraining agent form small pores, mesopores and macropores after hardening, forming a "small pore-mesopore-macropore" system, forming three-stage purification, and significantly improving the water purification capacity.

[0013] According to the above scheme, the water reducing agent is one of polycarboxylic acid water reducing agent and naphthalene series water reducing agent, and the water reducing rate is 15-25%.

[0014] The application also provides a preparation method of the water purification concrete, which comprises the following steps:

[0015] ​(1) Put the aggregate and part of the composite slurry in a stirring pot according to the proportion, and perform a first stirring treatment, and then seal and stand; the aggregate absorbs the composite slurry into the internal pores of the aggregate during the sealing and standing process, and the light aggregate is used as a carrier of the composite slurry, which is slowly released and plays a role during the use of the concrete;

[0016] (2) Add the weighed cementing material, air entraining agent, water reducing agent and mixing water, and perform a second stirring treatment to obtain a concrete mixture, and then perform molding, mold curing, demolding and drying to obtain a net water concrete blank;

[0017] (3) Perform carbonization curing on the obtained net water concrete blank to obtain a cured concrete;

[0018] (4) Spray the remaining composite slurry on the cured concrete obtained in step (3), and then dry (naturally dry) to obtain a net water concrete product.

[0019] The effective components in the composite slurry can be directly distributed on the pore surface of the net water concrete after spraying, and fully play the purification effect.

[0020] In the above scheme, in step (1), the introduced composite slurry accounts for 40-60wt% of the total amount.

[0021] In the above scheme, the first stirring treatment time is 60-90s, and the second stirring treatment time is 90-120s (which can promote the formation of a three-level purification system of "small pores-middle pores-large pores").

[0022] In the above scheme, the sealing and standing time is 20-40min.

[0023] In the above scheme, the mold curing temperature is 20-30℃, and the curing time is 18-24h.

[0024] In the above scheme, the carbonization curing adopts a carbon dioxide concentration of 20-100%, a pressure of 0.1-0.5MPa, a temperature of 50-70℃, and a curing time of 6-24h.

[0025] The net water concrete prepared according to the above scheme has a bulk density of 1400-1600kg / m 3 , and a compressive strength of 15-20MPa, and when it is applied to purify sewage, the total nitrogen removal rate can reach more than 80%, the total phosphorus removal rate can reach more than 82%, the methyl orange removal rate can reach more than 88%, and the Pb 2+ removal rate can reach more than 92%.

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] (1) The present application uses low-carbon green materials such as γ-dicalcium silicate, slag and steel slag as cementitious materials, which significantly reduces the carbon footprint of concrete from two aspects: on the one hand, the production process of cementitious materials consumes less limestone and energy, and emits less carbon dioxide; on the other hand, the carbon dioxide curing process is used to prepare concrete, which absorbs a large amount of carbon dioxide through carbonation reaction during curing, realizes carbon sequestration, and significantly reduces the carbon footprint.

[0028] (2) The present application uses the process of carbon dioxide curing concrete to reduce the pH value of water purification concrete, which can maintain a low alkaline environment for a long time and provide a suitable living environment for plants.

[0029] (3) The present application can significantly improve the water purification effect of the phytogenic concrete, improve the removal capacity of the concrete for total nitrogen (TN), total phosphorus (TP), organic matter and heavy metal ions and other pollutants in complex water bodies; by using the constructed "small pore-middle pore-large pore" system, three-stage purification is realized, and the water purification efficiency is significantly improved; by spraying the composite slurry on the surface of the concrete, it is evenly distributed on the pore surface of the water purification concrete, and its purification effect is fully played; and through the composite slurry loaded by the aggregate, it is slowly released during the later use process, and can continuously degrade and purify the pollutants under sunlight.

[0030] (4) The composite slurry has a synergistic effect between chitosan and nano titanium dioxide, which effectively enhances the carbonation performance, improves the purification and adsorption capacity of pollutants, enhances the photocatalytic degradation performance, and greatly improves the strength, water permeability and water purification capacity of the concrete. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below with examples. It should be understood that the specific examples described herein are only used to explain the present application, and are not used to limit the present application.

[0032] In the following examples, the performance test methods are as follows:

[0033] The water purification concrete was immersed in simulated wastewater containing total nitrogen (TN), total phosphorus (TP), methyl orange (simulated organic pollutants) and Pb 2+ , respectively, and the ultraviolet light source was turned on for 12 hours every day to irradiate the wastewater. After 7 days of immersion, the wastewater was taken for water quality analysis. The test of total nitrogen (TN) refers to "Determination of Total Nitrogen in Water - Alkaline Persulfate Digestion Ultraviolet Spectrophotometric Method"

[0034] (HJ636-2012), the test of total phosphorus (TP) refers to "Determination of Phosphate and Total Phosphorus in Water - Continuous Flow Ammonium Molybdate Spectrophotometric Method" (HJ670-2013), the test of methyl orange content uses a spectrophotometer, and the test of Pb 2+The content is tested by atomic absorption spectrometer.

[0035] Example 1

[0036] A water purification concrete, each component and the weight percentage are as follows: cementitious material 40 parts, aggregate 85 parts, composite slurry 15 parts, air entraining agent 0.003 parts, water reducing agent 0.5 parts, mixing water 14 parts;

[0037] The cementitious material is composed of γ-dicalcium silicate, slag and steel slag, the mass ratio of γ-dicalcium silicate, slag and steel slag is 1:0.8:0.2, and the specific surface area of the mixture after powder grinding is 500m 2 / kg; the aggregate is natural zeolite, the particle size is 10-15mm, the cylinder compressive strength is 3MPa, the bulk density is 900kg / m 3 , and the water absorption rate is 7%;

[0038] The composite slurry is composed of chitosan and nano titanium dioxide, the concentration is 5wt%, the mass ratio of chitosan and nano titanium dioxide is 1:2, the nano titanium dioxide is anatase type, and the particle size is 10nm;

[0039] The air entraining agent is sodium dodecyl sulfate, and the water reducing agent is polycarboxylic acid water reducing agent, the water reducing rate is 25%.

[0040] The preparation method of the water purification concrete comprises the following steps:

[0041] (1) Put the aggregate and 40% of the composite slurry according to the proportion into a stirring pot, stir for 60s and seal and stand for 30min;

[0042] (2) Put the cementitious material, air entraining agent, water reducing agent and mixing water according to the proportion into the stirring pot, stir with the aggregate and composite slurry added in step (1) for 120s to obtain a concrete mixture; then place it in a mold, and cure in a 25℃ environment for 24h, demold to obtain a water purification concrete blank;

[0043] (3) Put the obtained water purification concrete blank into a reaction kettle with a carbon dioxide concentration of 100%, a pressure of 0.3MPa and a temperature of 50℃ for curing for 8h to obtain a cured concrete;

[0044] (4) Spray the remaining composite slurry in step (1) on the cured concrete in step (3), and naturally dry to obtain a water purification concrete product.

[0045] The water purification concrete obtained in this example has the bulk density, compressive strength, total nitrogen (TN), total phosphorus (TP), methyl orange and Pb 2+ removal rate test results shown in Table 1.

[0046] Example 2

[0047] A water purification concrete, the components and the weight percentage are as follows: cementing material 40 parts, aggregate 90 parts, composite slurry 12 parts, air entraining agent 0.003 parts, water reducing agent 0.5 parts, mixing water 14 parts;

[0048] The cementing material is composed of γ-dicalcium silicate, slag and steel slag, the mass ratio of γ-dicalcium silicate, slag and steel slag is 1:0.6:0.4, and the specific surface area of the mixture after powder grinding is 500 m 2 / kg; the aggregate is shale ceramsite, the particle size is 10-15 mm, the cylinder compressive strength is 4 MPa, the bulk density is 900 kg / m 3 , and the water absorption rate is 8%;

[0049] The composite slurry is composed of chitosan and nano titanium dioxide with a concentration of 5 wt%, the mass ratio of chitosan to nano titanium dioxide is 1:2, the nano titanium dioxide is anatase type, and the particle size is 15 nm;

[0050] The air entraining agent is sodium dodecyl benzene sulfonate; the water reducing agent is naphthalene-based water reducing agent, and the water reducing rate is 15%;

[0051] The preparation method of the water purification concrete comprises the following steps:

[0052] (1) Put the aggregate and 60% of the composite slurry in the stirring pot according to the proportion, stir for 90 s and seal and stand for 40 min;

[0053] (2) Put the cementing material, air entraining agent, water reducing agent and mixing water into the stirring pot according to the proportion, stir with the aggregate and composite slurry added in step (1) for 120 s, obtain the concrete mixture, place it in the mold, and cure in the environment at 25℃ for 24 h, demold to obtain the water purification concrete blank;

[0054] (3) Put the water purification concrete blank obtained in step (2) into a reaction kettle with a carbon dioxide concentration of 100%, a pressure of 0.3 MPa and a temperature of 50℃, and cure for 8 h to obtain the cured concrete;

[0055] (4) Spray the remaining composite slurry in step (1) on the cured concrete in step (3), and naturally dry to obtain the water purification concrete product.

[0056] The water purification concrete obtained in this example has the test results of bulk density, compressive strength, total nitrogen (TN), total phosphorus (TP), methyl orange and Pb 2+ removal rate in simulated sewage as shown in Table 1.

[0057] Example 3

[0058] A water purification concrete, each component and the weight percentage are as follows: cementitious material 55 parts, aggregate 65 parts, composite slurry 13 parts, air entraining agent 0.005 parts, water reducing agent 0.7 parts, mixing water 13 parts;

[0059] The cementitious material used is composed of γ-dicalcium silicate, slag and steel slag, the mass ratio of γ-dicalcium silicate, slag and steel slag is 1:0.8:0.2, and the specific surface area of the mixture after powder grinding is 400 m 2 / kg; the aggregate is obtained by mixing shale ceramsite and sludge ceramsite at a mass ratio of 1:1, the particle size is 10-15 mm, the cylinder compressive strength is 3.5 MPa, the bulk density is 700 kg / m 3 , and the water absorption rate is 10%;

[0060] The composite slurry used is a slurry with a concentration of 5wt% composed of chitosan and nano titanium dioxide, the mass ratio of chitosan to nano titanium dioxide is 1:2, the nano titanium dioxide is anatase type, and the particle size is 20 nm;

[0061] The air entraining agent used is triterpenoid saponin; the water reducing agent is polycarboxylic acid water reducing agent, and the water reducing rate is 25%;

[0062] The preparation method of the water purification concrete comprises the following steps:

[0063] (1) Put the aggregate and 50% of the composite slurry weighed according to the proportion into a stirring pot, stir for 60s and seal and stand for 30min;

[0064] (2) Pour the cementitious material, air entraining agent, water reducing agent and mixing water weighed according to the proportion into the stirring pot, stir with the aggregate and composite slurry added in step (1) for 120s to obtain a concrete mixture; then place it in a mold, and cure in a 25℃ environment for 24h, demold to obtain a water purification concrete blank;

[0065] (3) Place the obtained water purification concrete blank in a reaction kettle with a carbon dioxide concentration of 20%, a pressure of 0.5MPa and a temperature of 60℃ for 24h to obtain a cured concrete;

[0066] (4) Spray the remaining composite slurry in step (1) on the cured concrete in step (3), and naturally dry to obtain a water purification concrete finished product.

[0067] The water purification concrete obtained in this example has a bulk density, compressive strength, and total nitrogen (TN), total phosphorus (TP), methyl orange and Pb 2+ removal rate test results are shown in Table 1.

[0068] Comparative Example 1

[0069] A water purification concrete is prepared in substantially the same manner as in Example 1, except that the natural zeolite is replaced by the same volume of limestone crushed stone.

[0070] The concrete bulk density, compressive strength, and total nitrogen (TN), total phosphorus (TP), methyl orange, and Pb in simulated sewage in the present comparative example 2+ The removal rate test results are shown in Table 1.

[0071] Comparative Example 2

[0072] A water purification concrete is prepared in substantially the same manner as in Example 2, except that the composite slurry is divided into chitosan slurry and nano-titanium dioxide slurry, and the same amount of chitosan slurry is added in step (1), and the same amount of nano-titanium dioxide slurry is sprayed in step (4).

[0073] The concrete bulk density, compressive strength, and total nitrogen (TN), total phosphorus (TP), methyl orange, and Pb in simulated sewage in the present comparative example 2+ The removal rate test results are shown in Table 1.

[0074] Comparative Example 3

[0075] A water purification concrete is prepared in substantially the same manner as in Example 3, except that the stirring time in step (2) is 30 s.

[0076] The concrete bulk density, compressive strength, and total nitrogen (TN), total phosphorus (TP), methyl orange, and Pb in simulated sewage in the present comparative example 2+ The removal rate test results are shown in Table 1.

[0077] Comparative Example 4

[0078] A water purification concrete is prepared in substantially the same manner as in Example 1, except that the 100% amount of composite slurry is put into the stirring pot for stirring in step (1), and no composite slurry is sprayed in step (4).

[0079] The concrete bulk density, compressive strength, and total nitrogen (TN), total phosphorus (TP), methyl orange, and Pb in simulated sewage in the present comparative example 2+ The removal rate test results are shown in Table 1.

[0080] Table 1: Performance test results of the concrete obtained in Examples 1-3 and Comparative Examples 1-4:

[0081]

[0082] From the above performance test results, it can be seen that the water purification concrete of Examples 1-3 has a total nitrogen (TN), total phosphorus (TP), methyl orange, and Pb 2+The removal rates of the water purification concrete are significantly higher than those of the comparative examples 1-4. The water purification concrete according to the present application has a total nitrogen removal rate of more than 80%, a total phosphorus removal rate of more than 82%, a methyl orange removal rate of more than 88%, a Pb 2+ removal rate of more than 92%, which is significantly higher than the water purification efficiency of ordinary vegetation concrete, and can be self-cleaning, avoid the blockage of the pores of the concrete, and greatly prolong the water permeability and water purification capacity of the water purification concrete.

[0083] The specific embodiments of the present application described above do not constitute a limitation on the protection scope of the present application. Any various other corresponding changes and modifications made according to the technical concept of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A water-cleansing concrete, characterized by, The components and the weight percentage of each component are as follows: cementing material 30-55 parts, aggregate 65-95 parts, composite slurry 10-20 parts, air entraining agent 0.003-0.01 parts, water reducing agent 0.4-0.8 parts, and mixing water 10-15 parts; the cementing material is γ-dicalcium silicate, slag and steel slag, and the mass ratio of γ-dicalcium silicate, slag and steel slag is 1:(0.8-0.2):(0.2-0.8); the composite slurry is a mixture of chitosan and nano titanium dioxide; The preparation method of the water purification concrete comprises the following steps: (1) placing the aggregate and part of the composite slurry in a stirring pot according to the proportioning and mixing, and then carrying out a first stirring treatment and closed standing; the aggregate absorbs the composite slurry into the internal pores of the aggregate during the closed standing, and the light-weight aggregate is used as a carrier of the composite slurry, which is slowly released and plays a role in the use of the concrete; the aggregate is a light-weight porous aggregate; (2) adding the cementing material, air entraining agent, water reducing agent and mixing water, and then carrying out a second stirring treatment to obtain a concrete mixture, and then performing molding, mold curing, demolding and drying to obtain a water purification concrete blank; (3) carbonizing and curing the water purification concrete blank to obtain a cured concrete; (4) spraying the remaining composite slurry on the cured concrete obtained in step (3) and then drying to obtain a water purification concrete product.

2. The pervious concrete of claim 1, wherein, The specific surface area of the cementitious material is 300-500 m 2 / kg.

3. The pervious concrete of claim 1, wherein, The particle size of the aggregate is 10-15 mm, the cylinder compression strength is not less than 3 MPa, the bulk density is 600-900 kg / m 3 , and the water absorption is 5-20%.

4. The pervious concrete of claim 1, wherein, The concentration of the composite slurry is 4-6 wt%, and the mass ratio of chitosan to nano titanium dioxide is 1:(2-1).

5. The pervious concrete of claim 1, wherein, The air entraining agent is at least one of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and triterpene saponin.

6. The pervious concrete of claim 1, wherein The water reducing agent is one of polycarboxylic acid water reducing agent and naphthalene series water reducing agent, and the water reducing rate is 15-25%.

7. A method of producing the water-cleaning concrete according to any one of claims 1 to 6, characterized by, The preparation method comprises the following steps: (1) placing the aggregate and part of the composite slurry in a stirring pot according to the proportioning and mixing, and then carrying out a first stirring treatment and closed standing; the aggregate absorbs the composite slurry into the internal pores of the aggregate during the closed standing, and the light-weight aggregate is used as a carrier of the composite slurry, which is slowly released and plays a role in the use of the concrete; (2) adding the cementing material, air entraining agent, water reducing agent and mixing water, and then carrying out a second stirring treatment to obtain a concrete mixture, and then performing molding, mold curing, demolding and drying to obtain a water purification concrete blank; (3) carbonizing and curing the water purification concrete blank to obtain a cured concrete; (4) spraying the remaining composite slurry on the cured concrete obtained in step (3) and then drying to obtain a water purification concrete product.

8. The preparation method according to claim 7, characterized in that, In step (1), the introduced composite slurry accounts for 40-60 wt% of the total amount of the composite slurry.

9. The preparation method according to claim 7, characterized in that, The first stirring treatment time is 60-90 s.

10. The preparation method according to claim 7, characterized in that, The carbonization curing adopts a carbon dioxide concentration of 20-100%, a pressure of 0.1-0.5 MPa, a temperature of 50-70℃ and a curing time of 6-24 h.

Images