Environment-friendly concrete water reducing agent and preparation method thereof

Abstract

The invention discloses an environment-friendly concrete water reducing agent and a preparation method thereof, and belongs to the technical field of concrete water reducing agents. The environment-friendly concrete water reducing agent is prepared from the following raw materials in parts by weight: 35 to 45 parts of modified lignosulfonate, 20 to 30 parts of polycarboxylic acid water reducing agent, 3 to 6 parts of coconut fiber-chitin compound, 10 to 15 parts of carboxymethyl starch, 8 to 12 parts of vegetable oil and 1 to 3 parts of sodium gluconate, the coconut fiber-chitin compound is prepared from coconut fibers and chitin nanocrystals through a compounding process. According to the environment-friendly concrete water reducing agent and the preparation method thereof, chitin nanocrystals are loaded on macroscopic porous structures of coconut fibers in a coconut-chitin compound, a micro-nano graded enhanced network is formed, amino groups of chitin and carboxyl groups of the modified coconut fibers can form ionic bonds, the stability of the compound is enhanced, and the water reducing effect is improved. Under the synergistic effect with the polycarboxylic acid type water reducing agent, the water reducing rate is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete water reducing agents, in particular to an environmentally friendly concrete water reducing agent and a preparation method thereof. Background Art

[0002] Concrete water reducers are the core admixtures of modern concrete technology, which can significantly improve the fluidity, strength and durability of concrete. Traditional water reducers (such as naphthalene and aliphatic series) rely on non-renewable petrochemical raw materials, produce a large amount of pollutants (such as formaldehyde and SO2) during the production process, and have poor biodegradability. Although polycarboxylic acid water reducers (PCE) have excellent performance, their synthesis requires the use of monomers such as acrylic acid, which poses environmental risks. Lignin sulfonate, as a by-product of papermaking waste liquid, is renewable, but has a low water reduction rate (<15%) when used directly, and has poor compatibility with cement. In addition, existing water reducers still have deficiencies in crack resistance, impermeability, etc., and bio-based materials such as vegetable oils and plant polysaccharides have limited dispersion efficiency when used alone. At present, although some studies have attempted to compound biomass materials (such as lignin and starch) with synthetic water reducers, the following problems exist:

[0003] Poor component synergy: The compatibility between bio-based materials and synthetic water reducers is insufficient, which can easily lead to phase separation or performance fluctuations;

[0004] Single function: Most formulas only focus on water reduction rate, ignoring durability requirements such as crack resistance and impermeability;

[0005] Low waste utilization rate: Agricultural / aquatic waste such as coconut coir and chitin are not used efficiently. Summary of the Invention

[0006] The present invention aims to provide an environmentally friendly concrete water reducer and a preparation method thereof. The invention utilizes the macroscopic porous structure of coconut fiber in a coconut coir-chitin composite to load chitosan nanocrystals to form a "micro-nano" hierarchical reinforcement network. The amino groups of chitosan and the carboxyl groups of the modified coconut fiber can form ionic bonds, thereby enhancing the stability of the composite. The composite synergistically acts with a polycarboxylic acid-based water reducer to improve the water reduction rate, thereby solving the problems raised in the above-mentioned background technology.

[0007] To achieve the above objectives, the present invention provides the following technical solution: an environmentally friendly concrete water reducer, comprising the following raw materials in parts by weight: 35-45 parts of modified lignin sulfonate, 20-30 parts of a polycarboxylic acid-based water reducer, 3-6 parts of a coconut palm-chitin composite, 10-15 parts of carboxymethyl starch, 8-12 parts of vegetable oil, and 1-3 parts of sodium gluconate. The coconut palm-chitin composite is prepared by a composite process using coconut palm and chitin nanocrystals. Coconut palm is rich in cellulose and has a porous structure and fiber toughness, making it suitable as a carrier or reinforcing phase. The chitin nanocrystals are rigid nanoparticles with a surface rich in amino groups, which can provide chemically active sites.

[0008] Preferably, the modified lignin sulfonate is prepared from sodium lignin sulfonate extracted from papermaking waste liquid as the main raw material, which is subjected to oxidation treatment to break the β-O-4 ether bond, reduce the molecular weight, expose the active group, and then introduce the sulfonic acid group (-SO3H) to obtain the modified lignin sulfonate. The introduced sulfonic acid group (-SO3H) enhances the anionic charge density. The specific method is as follows: sodium lignin sulfonate extracted from papermaking waste liquid is selected, the molecular weight of sodium lignin sulfonate is 10,000-20,000Da, the purity is ≥85%, and the sugar and ash are removed; the lignin sulfonate is prepared into a 20%-30% aqueous solution, stirred at 60°C until completely dissolved, 5%-10% of the mass of sodium lignin sulfonate H2O2 is added, and the pH is adjusted to 9-11 with NaOH. The temperature is The method comprises the steps of: heating the lignin solution at 50-60°C for 2-3 hours, purging with nitrogen to prevent excessive degradation, cooling to 30°C, neutralizing with dilute H2O2 to a pH of 7-8, reducing the molecular weight to 3,000-5,000 Da after oxidation, and ensuring that the carboxyl (-COOH) content is ≥1.5 mmol / g after oxidation; adding Na2SO3 (8%-12% by weight of sodium lignin sulfonate) to the oxidized lignin solution, adjusting the pH to 3-4, heating to 80-85°C, and reacting for 2-3 hours. After the reaction is completed, the solution is cooled to room temperature, adjusting the pH to 7-8 with NaOH, dialyzing to remove unreacted salts, and concentrating to a solid content of 30%-40%, a sulfonic acid content ≥2.0 mmol / g, and a sulfur retention rate ≥90%.

[0009] Preferably, the preparation method of the coconut palm-chitin composite is as follows: immersing microfibrillated coconut palm into a chitosan nanocrystal suspension at a mass ratio of 1:1, assisted by 40kHz ultrasound for 1 hour to embed the nanocrystals into the fiber pores, adding epichlorohydrin in an amount of 5% of the total mass of the coconut palm and chitosan nanocrystals, reacting at 60°C for 3 hours to form a covalent cross-linked network, freeze-drying and then grinding to obtain a coconut palm-chitosan composite powder.

[0010] Preferably, the coconut palm-chitin composite powder is further subjected to sulfonation treatment and hydrophobic modification to finally obtain a coconut palm-chitin composite. The sulfonation treatment and hydrophobic modification steps are as follows: Na2SO3 (10% by mass of the coconut palm-chitin composite powder) is reacted with the coconut palm-chitin composite powder at 80°C for 2h to introduce -SO3 - group, improve water-reducing dispersibility; treated with silane coupling agent to enhance compatibility with vegetable oil, the -SO3 - The chitin nanocrystals synergistically enhance electrostatic repulsion with lignin, and the amino groups of chitin nanocrystals adsorb Ca 2+ , delaying hydration and releasing more free water. Coconut coir and chitin are both waste resources.

[0011] Preferably, the coconut coir processing method is as follows: the method for obtaining microfibrillated coconut coir is as follows: the coconut coir is crushed to 1-3 mm, treated with 5% NaOH solution at 80°C for 2h to remove lignin, bleached with H2O2 at 60°C, and hydrolyzed with citric acid at 50°C for 4h to obtain microfibrillated coconut coir with a diameter of 10-50μm.

[0012] Preferably, the chitosan nanocrystals are obtained by deproteinizing shrimp or crab shells with 4% NaOH and decalcifying with 3% HCl, hydrolyzing with 40% HCl for 2 h, and dialyzing to neutrality to obtain a nanocrystal suspension with a solid content of 2%-3%.

[0013] Preferably, the polycarboxylic acid water reducer is of hydroxypropyl polyoxyethylene ether type or isopentanol polyoxyethylene ether type, with a molecular weight of 3000 to 5000 and a side chain density of 8 to 12 side chains per main chain.

[0014] Preferably, the carboxymethyl starch is corn carboxymethyl starch with a DS of 0.3-0.5. The starch is reacted with NaOH and monochloroacetic acid in ethanol or water for 4 hours at a reaction temperature of 60° C., and the degree of substitution is controlled at 0.3-0.5.

[0015] Preferably, the vegetable oil is epoxidized soybean oil or epoxidized castor oil. The long-chain fatty acid ester is adsorbed on the surface of cement particles to reduce the friction coefficient. The vegetable oil fills the uncovered area of ​​the polycarboxylic acid water reducer side chain through a synergistic effect with the polycarboxylic acid water reducer to form a complete lubricating film.

[0016] Another technical problem to be solved by the present invention is to provide a method for preparing an environmentally friendly concrete water reducing agent, comprising the following steps:

[0017] Mix the vegetable oil and polycarboxylic acid water reducer and disperse them ultrasonically at 20kHz and 40℃ for 15min;

[0018] Add coconut palm-chitin complex and continue ultrasonication for 10 min;

[0019] Add oxidized-sulfonated lignin, carboxymethyl starch, and sodium gluconate in sequence and stir at 60°C for 1 h;

[0020] 50MPa high pressure homogenization, 2 cycles, ensure the particle size is ≤1μm, filter with 200 mesh screen;

[0021] The concrete water reducer is made into a liquid product or a solid product. The liquid product is added with water and the solid content is adjusted to 40%-50%. The solid product is spray dried with an inlet air temperature of 180°C and an outlet air temperature of 80°C, and the moisture content is controlled to be ≤5%.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The invention discloses an environmentally friendly concrete water reducer and a preparation method thereof. The macroscopic porous structure of coconut fiber in a coconut fiber-chitin composite is loaded with chitin nanocrystals to form a "micro-nano" hierarchical reinforcement network. The amino groups of chitin and the carboxyl groups of the modified coconut fiber can form ionic bonds to enhance the stability of the composite. The composite synergistically acts with a polycarboxylic acid-based water reducer to improve the water reduction rate. The coconut fiber bridges microcracks to reduce the crack area, the chitin nanocrystals fill the capillary pores, and the epoxidized vegetable oil introduces uniform microbubbles, thereby improving the frost resistance. The lignin, coconut fiber, chitin and vegetable oil are all renewable resources or wastes, have a high biodegradability and are free of toxic residues. DETAILED DESCRIPTION

[0024] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] Example 1:

[0026] Take the following materials:

[0027] 40 parts of modified lignin sulfonate, 25 parts of polycarboxylic acid water reducer, 5 parts of coconut palm-chitin composite, 12 parts of carboxymethyl starch (DS 0.4), 10 parts of epoxidized soybean oil and 2 parts of sodium gluconate.

[0028] Specifically, the preparation method of the modified lignin sulfonate is as follows:

[0029] Sodium lignin sulfonate extracted from papermaking wastewater is selected, the molecular weight of the sodium lignin sulfonate is 10,000-20,000Da, the purity is ≥85%, and sugar and ash are removed; the lignin sulfonate is prepared into a 20%-30% aqueous solution, stirred at 60°C until completely dissolved, H2O2 with a mass percentage of 8% of the sodium lignin sulfonate is added, H2O2 is a 30% solution, the pH is adjusted to 10 with NaOH, the temperature is 52°C, the reaction is carried out for 3 hours, nitrogen is passed through to prevent excessive degradation, after the reaction is completed, the temperature is lowered to 30°C, and diluted H2O2 is used to neutralize to The method comprises the following steps: adding Na2SO3 (10% by weight of sodium lignin sulfonate) to the oxidized lignin solution at a pH of 7, adjusting the molecular weight to 3,000-5,000 Da after oxidation, and maintaining a carboxyl (-COOH) content of 1.5 mmol / g after oxidation; and adding Na2SO3 (10% by weight of sodium lignin sulfonate) to the oxidized lignin solution to adjust the pH to 4. The solution is heated to 80°C and reacted for 3 hours. After the reaction is completed, the solution is cooled to room temperature, and the pH is adjusted to 7 with NaOH. The solution is dialyzed to remove unreacted salts and concentrated to a solid content of 30%-40%, a sulfonic acid content of 2.0 mmol / g, and a sulfur retention rate of 90%.

[0030] The preparation method of modified lignin sulfonate is as follows:

[0031] Coconut coir was crushed to 1-3 mm, treated with 5% NaOH solution at 80 ° C for 2 h to remove lignin, bleached with H2O2 at 60 ° C, and hydrolyzed with citric acid at 50 ° C for 4 h to obtain microfibrillated coconut coir with a diameter of 10-50 μm.

[0032] The shrimp shell or crab shell is deproteinized with 4% NaOH and decalcified with 3% HCl, and then hydrolyzed with 40% HCl for 2 hours and dialyzed to neutrality to obtain a nanocrystalline suspension with a solid content of 2%-3% to prepare chitosan.

[0033] Microfibrillated coconut coir was immersed in a chitosan nanocrystal suspension at a mass ratio of 1:1, and assisted by 40kHz ultrasound for 1 hour to embed the nanocrystals into the fiber pores. Epichlorohydrin was added at an amount of 5% of the total mass of coconut coir and chitosan nanocrystals, and reacted at 60°C for 3 hours to form a covalent cross-linked network. The powder was freeze-dried and then ground to obtain coconut coir-chitosan composite powder.

[0034] Take 10% of the mass of coconut palm-chitin composite powder Na2SO3 and react with coconut palm-chitin composite powder at 80℃ for 2h to introduce -SO3 - group, improve water-reducing dispersibility; treated with silane coupling agent to enhance compatibility with vegetable oil, the -SO3 - The chitin nanocrystals synergistically enhance electrostatic repulsion with lignin, and the amino groups of chitin nanocrystals adsorb Ca 2+ , delaying hydration and releasing more free water. Coconut coir and chitin are both waste resources.

[0035] The above materials are processed as follows:

[0036] Epoxidized soybean oil and polycarboxylate water reducer were ultrasonically mixed at 20 kHz for 15 min.

[0037] Add coconut palm-chitin complex and continue ultrasonication for 10 min;

[0038] Add the remaining components in sequence, stir at 60°C for 1 h, and homogenize under high pressure at 50 MPa for 2 cycles to ensure that the particle size is ≤1 μm, and filter with a 200-mesh sieve;

[0039] Spray drying, air inlet 180℃, air outlet 80℃, control moisture ≤5%.

[0040] Example 2:

[0041] In this embodiment, the following materials are used to prepare the environmentally friendly concrete water reducing agent:

[0042] 35 parts of modified lignin sulfonate, 30 parts of polycarboxylic acid water reducer, 3 parts of coconut palm-chitin composite, 10 parts of carboxymethyl starch (DS 0.4), 8 parts of epoxidized soybean oil and 1 part of sodium gluconate.

[0043] Here’s how:

[0044] Epoxidized soybean oil and polycarboxylate water reducer were ultrasonically mixed at 20 kHz for 15 min.

[0045] Add coconut palm-chitin complex and continue ultrasonication for 10 min;

[0046] Add the remaining components in sequence, stir at 60°C for 1 h, and homogenize under high pressure at 50 MPa for 2 cycles to ensure that the particle size is ≤1 μm, and filter with a 200-mesh sieve;

[0047] Spray drying, air inlet 180℃, air outlet 80℃, control moisture ≤5%.

[0048] Example 3:

[0049] In this embodiment, the following materials are used to prepare the environmentally friendly concrete water reducing agent:

[0050] 45 parts of modified lignin sulfonate, 20 parts of polycarboxylic acid water reducer, 6 parts of coconut palm-chitin composite, 15 parts of carboxymethyl starch (DS 0.4), 12 parts of epoxidized soybean oil and 3 parts of sodium gluconate.

[0051] Here’s how:

[0052] Epoxidized soybean oil and polycarboxylate water reducer were ultrasonically mixed at 20 kHz for 15 min.

[0053] Add coconut palm-chitin complex and continue ultrasonication for 10 min;

[0054] Add the remaining components in sequence, stir at 60°C for 1 h, and homogenize under high pressure at 50 MPa for 2 cycles to ensure that the particle size is ≤1 μm, and filter with a 200-mesh sieve;

[0055] Add water and adjust the solid content to 45% to make a liquid product.

[0056] The environmentally friendly concrete water reducer prepared in the above embodiment was subjected to performance testing to obtain the following data table:

[0057]

[0058]

[0059] The present invention achieves a high water reduction rate through the synergistic effect of the oxidation-sulfonation modified lignin sulfonate and the polycarboxylic acid-based water reducer. The sulfonic acid group content of the modified lignin is ≥2.0 mmol / g, which significantly improves the dispersion effect of cement particles.

[0060] Comparative Example 1:

[0061] In this comparative example, the following materials were used to prepare the environmentally friendly concrete water reducer:

[0062] 40 parts of lignin sulfonate, 25 parts of polycarboxylic acid water reducer, 5 parts of coconut palm-chitin composite, 12 parts of carboxymethyl starch (DS 0.4), 10 parts of epoxidized soybean oil and 2 parts of sodium gluconate.

[0063] An environmentally friendly concrete water reducer was prepared by the same method as in Example 1. In this comparative example, the lignin sulfonate was not modified, and the molecular weight of the lignin was large, ranging from 10,000 to 20,000 Da.

[0064] Comparative Example 2:

[0065] In this comparative example, the following materials were used to prepare the environmentally friendly concrete water reducer:

[0066] 40 parts of modified lignin sulfonate, 25 parts of polycarboxylic acid water reducer, 12 parts of carboxymethyl starch (DS 0.4), 10 parts of epoxidized soybean oil and 2 parts of sodium gluconate.

[0067] In this comparative example, the coconut palm-chitin composite was omitted, and other materials were the same as those in Example 1. The environmentally friendly concrete water reducer was prepared using the same method as in Example 1.

[0068] Comparative Example 3:

[0069] In this comparative example, the following materials were used to prepare the environmentally friendly concrete water reducer:

[0070] 40 parts of modified lignin sulfonate, 25 parts of polycarboxylic acid water reducer, 5 parts of chitin, 12 parts of carboxymethyl starch (DS 0.4), 10 parts of epoxidized soybean oil and 2 parts of sodium gluconate.

[0071] In this comparative example, chitosan was used instead of the coconut palm-chitosan composite, and other materials were the same as those in Example 1. The same method as in Example 1 was used to prepare an environmentally friendly concrete water reducer.

[0072] The performance of the environmentally friendly concrete water reducing agent prepared in Example 1 and the comparative example was tested, and the following data were obtained:

[0073]

[0074]

[0075] It can be concluded from the above table that the comparative example 1 uses unmodified lignin with high molecular weight, the sulfonic acid groups are wrapped, the cement particles cannot be effectively dispersed, the water retention effect of the carboxyl groups (-COOH) introduced by oxidation is lacking, the free water evaporates quickly, resulting in a sudden drop in fluidity, and the chloride ion diffusion coefficient is as high as 2.80×10-12m2 / s, because the unmodified lignin cannot optimize the pore structure; in the comparative example 2, the coconut palm-chitin composite is not used, the crack area increases, due to the lack of the bridging effect of coconut palm fiber and the pore filling of chitin nanocrystals, while -SO3 - The groups synergistically enhance the electrostatic repulsion with lignin, and the water reduction rate decreases after its loss; in comparative example three, pure chitin nanocrystals are easily agglomerated due to the action of surface amino hydrogen bonds, resulting in fluctuations in the water reduction rate and increased concrete viscosity. Due to the lack of lubrication of coconut fiber, the pumping resistance increases.

[0076] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0077] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. An environmentally friendly concrete water reducer, characterized in that: The invention comprises the following raw materials in parts by weight: 35-45 parts of modified lignin sulfonate, 20-30 parts of polycarboxylic acid water reducer, 3-6 parts of coconut palm-chitin composite, 10-15 parts of carboxymethyl starch, 8-12 parts of vegetable oil and 1-3 parts of sodium gluconate. The coconut palm-chitin composite is prepared by a composite process of coconut palm and chitin nanocrystals.

2. The environmentally friendly concrete water reducing agent according to claim 1, characterized in that: The modified lignin sulfonate is obtained by using sodium lignin sulfonate extracted from papermaking waste liquid as the main raw material, undergoing oxidation treatment to break the β-O-4 ether bond and then introducing a sulfonic acid group. The specific method is as follows: sodium lignin sulfonate extracted from papermaking waste liquid is selected, the molecular weight of the sodium lignin sulfonate is 10,000-20,000 Da, the purity is ≥85%, and sugar and ash are removed; the lignin sulfonate is prepared into a 20%-30% aqueous solution, stirred at 60°C until completely dissolved, 5%-10% of the mass of the sodium lignin sulfonate in H2O2 is added, and N The pH value is adjusted to 9-11 with aOH, the temperature is 50-60°C, the reaction is carried out for 2-3 hours, nitrogen is passed through to prevent excessive degradation, and after the reaction is completed, the temperature is lowered to 30°C and the solution is neutralized to a pH value of 7-8 with dilute H2O2; Na2SO3 (8%-12% by mass of sodium lignin sulfonate) is added to the oxidized lignin solution, the pH value is adjusted to 3-4, the temperature is raised to 80-85°C, the reaction is carried out for 2-3 hours, and after the reaction is completed, the solution is cooled to room temperature, the pH value is adjusted to 7-8 with NaOH, unreacted salts are removed by dialysis, and the solution is concentrated to a solid content of 30%-40%.

3. The environmentally friendly concrete water reducing agent according to claim 2, characterized in that: The preparation method of the coconut palm-chitin composite is as follows: immersing microfibrillated coconut palm into a chitosan nanocrystal suspension at a mass ratio of 1:1, performing 40kHz ultrasonic assistance for 1 hour to embed the nanocrystals into the fiber pores, adding epichlorohydrin in an amount of 5% of the total mass of the coconut palm and chitosan nanocrystals, reacting at 60°C for 3 hours to form a covalent cross-linked network, freeze-drying, and then grinding to obtain a coconut palm-chitosan composite powder.

4. The environmentally friendly concrete water reducing agent according to claim 3, characterized in that: The coconut palm-chitin composite powder also needs to be subjected to sulfonation treatment and hydrophobic modification to finally obtain the coconut palm-chitin composite. The sulfonation treatment and hydrophobic modification steps are as follows: Na2SO3 (10% of the mass of the coconut palm-chitin composite powder) is reacted with the coconut palm-chitin composite powder at 80°C for 2h to introduce -SO3 - group; treated with a silane coupling agent.

5. The environmentally friendly concrete water reducing agent according to claim 3, characterized in that: The processing method of the coconut coir is as follows: the method for obtaining microfibrillated coconut coir is as follows: the coconut coir is crushed into 1-3 mm, treated with 5% NaOH solution at 80°C for 2 hours to remove lignin, bleached with H2O2 at 60°C, and hydrolyzed with citric acid at 50°C for 4 hours to obtain microfibrillated coconut coir.

6. The environmentally friendly concrete water reducing agent according to claim 3, characterized in that: The method for obtaining the chitosan nanocrystals is as follows: deproteinizing shrimp shells or crab shells with 4% NaOH, decalcifying with 3% HCl, hydrolyzing with 40% HCl for 2 hours, and dialyzing to neutrality to obtain a nanocrystal suspension with a solid content of 2%-3%.

7. The environmentally friendly concrete water reducing agent according to claim 1, characterized in that: The polycarboxylic acid water reducer is of hydroxypropyl polyoxyethylene ether type or isopentanol polyoxyethylene ether type, has a molecular weight of 3000 to 5000, and has a side chain density of 8 to 12 side chains per main chain.

8. The environmentally friendly concrete water reducing agent according to claim 1, characterized in that: The carboxymethyl starch is selected from corn carboxymethyl starch with a DS of 0.3-0.

5.

9. The environmentally friendly concrete water reducing agent according to claim 1, characterized in that: The vegetable oil is epoxidized soybean oil or epoxidized castor oil.

10. A method for preparing the environmentally friendly concrete water reducing agent according to any one of claims 1 to 9, characterized in that: The following steps are involved: Mix the vegetable oil and polycarboxylic acid water reducer and disperse them ultrasonically at 20kHz and 40℃ for 15min; Add coconut palm-chitin complex and continue ultrasonication for 10 min; Add oxidized-sulfonated lignin, carboxymethyl starch, and sodium gluconate in sequence and stir at 60°C for 1 h; 50MPa high pressure homogenization, 2 cycles to ensure the particle size is ≤1μm, and filter with a 200 mesh screen; The concrete water reducer is made into a liquid product or a solid product. The liquid product is added with water and the solid content is adjusted to 40%-50%. The solid product is spray dried with an inlet air temperature of 180°C and an outlet air temperature of 80°C, and the moisture content is controlled to be ≤5%.

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