An aquaculture water quality improver, a preparation method and application thereof

Abstract

This invention discloses an aquatic water quality improver, its preparation method, and its application. The aquatic water quality improver comprises the following components by mass percentage: 3%–20% sodium carboxymethyl trithiocarbonate, 5%–20% sodium carboxymethyl pentathiocarbonate, 2%–5% synergistic agent, 2%–10% detoxifier, and the balance being water. This aquatic water quality improver of the present invention has multiple effects, rapidly degrading nitrite in aquaculture water and reducing ammonia nitrogen content. It has functions such as water detoxification, bottom sediment improvement, and stress relief for farmed animals. It is harmless to fish, shrimp, crabs, algae, and beneficial bacteria, safe and non-toxic, highly stable, and resistant to acids and alkalis. It is suitable for the purification and environmental restoration of seawater and freshwater aquaculture water, and is fast-acting, significantly improving water quality within 24 hours, with an effective degradation rate of over 90% for nitrite in aquaculture water within 72 hours. This aquatic water quality improver of the present invention has the advantages of high efficiency, safety, and multifunctionality.

Description

Technical Field

[0001] This invention belongs to the field of aquatic environment management technology, specifically relating to an aquatic water quality improver, its preparation method, and its application. Background Technology

[0002] With the increasing intensification of aquaculture, toxic and harmful substances such as nitrite and ammonia nitrogen in aquaculture water are prone to accumulate and exceed standards, often leading to poisoning, hypoxia, disease, and even death of aquatic animals.

[0003] To address the aforementioned issues, researchers have proposed water quality improvers. However, existing water quality improvers generally suffer from drawbacks such as limited functionality, low degradation efficiency, and poor stability. For example, some researchers have formulated a water quality improver by adding sodium trithiocarbonate and sodium pentathiocarbonate to water. However, in practical applications, it has been found that although this product can effectively degrade nitrite, its use in large quantities poses a risk of fish mortality. In particular, it cannot be used in hot or rainy weather, and the dosage requirements are even stricter, which is not conducive to large-scale promotion and use. The reason is that under high temperature conditions, the dissolved oxygen content in the water decreases, the metabolism of aquatic animals accelerates, and oxygen consumption increases. At the same time, the reaction of certain agents is accelerated, which may further consume dissolved oxygen in the water or produce local high concentrations of toxic substances, thereby exacerbating the risk of hypoxia and poisoning. In addition, insufficient sunlight in rainy weather weakens the photosynthesis of algae and reduces oxygen production capacity, which can also easily lead to hypoxia in the water. At this time, the application of agents is more likely to induce stress or death in farmed animals. Furthermore, the active ingredient of this improver has strong chemical activity. If the dosage is too high, it can easily lead to excessively high local concentrations in the water, exceeding the tolerance range of aquatic animals, thereby causing damage or death. Therefore, this product is extremely sensitive to the dosage, and even a slight mistake can cause a safety accident.

[0004] Currently, there are few water quality conditioners on the market that combine excellent water quality improvement effects with high safety for aquatic organisms. Therefore, developing non-toxic or low-toxic water quality conditioners with excellent effects is of great significance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an efficient, safe and multifunctional aquatic water quality improver, its preparation method and application, which aims to achieve the synergistic removal of nitrite and ammonia nitrogen in aquaculture water.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: An aquatic water quality improver, comprising the following raw material components by mass percentage: Sodium carboxymethyl trithiocarbonate 3%–20%; Sodium carboxymethyl pentathiocarbonate 5%–20%; Synergistic additives 2%–5%; Antidote 2%–10%; The remainder is water.

[0007] Preferably, the aforementioned aquatic water quality improver comprises the following raw material components by mass percentage: Sodium carboxymethyl trithiocarbonate 3%–15%; Sodium carboxymethyl pentathiocarbonate 5%–15%; Synergistic additives 2%–3%; Antidote 2%–6%; The remainder is water.

[0008] Preferably, in the above-mentioned aquatic water quality improver, the detoxifying agent includes sodium thiosulfate and sodium carbonate, wherein the mass ratio of sodium thiosulfate to sodium carbonate is 1-2:1-3; the synergistic agent is selected from one or more of chelating agents, humates and surfactants.

[0009] Preferably, in the above-mentioned aquatic water quality improver, the chelating agent is disodium EDTA and / or sodium citrate; the humate is potassium humate and / or sodium humate; and the surfactant is at least one of sodium fatty alcohol polyoxyethylene ether sulfate, alkyl glycoside, and cocamidopropyl betaine.

[0010] Preferably, in the above-mentioned aquatic water quality improver, the mass ratio of sodium carboxymethyl trithiocarbonate to sodium carboxymethyl pentathiocarbonate is 1-4:1-4.

[0011] Preferably, the carboxymethyl sodium trithiocarbonate in the above-mentioned aquatic water quality improver is monocarboxymethyl sodium trithiocarbonate and / or dicarboxymethyl sodium trithiocarbonate.

[0012] Preferably, the carboxymethyl sodium trithiocarbonate mentioned above includes at least one of sodium carboxymethyl sodium trithiocarbonate, potassium carboxymethyl sodium trithiocarbonate, magnesium carboxymethyl sodium trithiocarbonate, and calcium carboxymethyl sodium trithiocarbonate.

[0013] Preferably, the carboxymethyl sodium pentathiocarbonate in the above-mentioned aquatic water quality improver is monocarboxymethyl sodium pentathiocarbonate and / or dicarboxymethyl sodium pentathiocarbonate.

[0014] Preferably, the aforementioned aquatic water quality improver includes at least one of sodium carboxymethyl pentathiocarbonate, sodium carboxymethyl pentathiocarbonate potassium, sodium carboxymethyl pentathiocarbonate magnesium, and sodium carboxymethyl pentathiocarbonate calcium.

[0015] As a general technical concept, the present invention also discloses a method for preparing the above-mentioned aquatic water quality improver, comprising the following steps: (1) Mix the antidote with water and dissolve it to obtain an antidote solution; (2) Add sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate to the antidote solution obtained in step (1) to obtain a mixed solution; (3) Add the synergist to the mixed solution obtained in step (2), stir, let stand, filter, and obtain the aquatic water quality improver product.

[0016] In the above preparation method, preferably, in step (3), the stirring time is 60 minutes to 90 minutes; and the standing time is 2 hours to 4 hours.

[0017] As a general technical concept, the present invention also discloses the application of the above-mentioned aquatic water quality improver or the aquatic water quality improver prepared by the above-mentioned preparation method in the treatment of aquaculture water bodies.

[0018] The above-mentioned application, preferably, includes: using an aquatic water quality improver to purify aquaculture water bodies, removing nitrite and ammonia nitrogen from the aquaculture water bodies; the dosage of the aquatic water quality improver is 100mL to 400mL per acre of aquaculture water with a depth of 1 meter; the treatment time is 24h to 96h.

[0019] This invention modifies the molecular structures of sodium trithiocarbonate and sodium pentathiocarbonate to reduce toxicity by introducing a carboxymethylation reaction into their molecular structures, namely:

[0020]

[0021] Further carboxymethylation produces sodium dicarboxymethyl trithiocarbonate and sodium dicarboxymethyl pentathiocarbonate, which are less toxic but more expensive. They can be widely used in high-end aquaculture where water quality requirements are extremely high.

[0022]

[0023]

[0024] Compared with the prior art, the advantages of the present invention are as follows: (1) In view of the shortcomings of existing water quality improvers, such as high toxicity, single function, low degradation efficiency, and poor stability, and the resulting defects such as great toxicity to aquatic organisms and difficulty in effectively purifying aquatic water bodies, this invention creatively proposes an aquatic water quality improver, which, by mass percentage, includes 3% to 20% sodium carboxymethyl trithiocarbonate, 5% to 20% sodium carboxymethyl pentathiocarbonate, 2% to 5% synergist, 2% to 10% antidote, and the balance being water. The core component of the aquatic water quality improver of this invention is sodium carboxymethyl polythiocarbonate, specifically including sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate. This component is prepared by carboxymethylation modification of trithiocarbonate and pentathiocarbonate. On the one hand, through carboxymethylation modification, the toxicity of sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate can be significantly reduced, and carboxymethyl groups exhibit very high biocompatibility, similar to the low acute toxicity of carboxymethyl cellulose (CMC) in fish. >100mg / L, with less toxicity to aquatic animals in water. On the other hand, through carboxymethylation modification, the content of carboxyl chelating groups and polysulfide reducing groups in sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate can be significantly increased, and their water solubility and chelation efficiency are significantly better than ordinary polysulfide inorganic salts, and their stability is greatly improved, which can bring the following unexpected technical effects: (a) Utilizing the carboxyl chelating groups and polysulfide reducing groups in the carboxyl methyl (-COO) group - ) and polysulfides (-S x -(a) Through the double chelation effect of polysulfide groups, the reducing properties of polysulfide ions in polysulfide reducing groups are utilized to efficiently reduce nitrite to harmless nitrogen gas, achieving rapid degradation of nitrite; (b) Through the interaction between carboxyl chelating groups and polysulfide reducing groups, the conversion and degradation of ammonia nitrogen are promoted through oxidation, complexation, and improvement of the microecology of aquatic bodies, effectively reducing the ammonia nitrogen content in water bodies; (c) Under the protection of carboxylmethyl groups, the stability of sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate can be significantly improved, and the stability of high-temperature sodium carboxymethyl trithiocarbonate can be improved. (d) Under warm and rainy weather conditions, it is not easily decomposed and will not form toxic or harmful gases; under the buffering effect of carboxymethyl, sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate have relatively lower chemical activity and milder pH value, and the pH value is close to neutral / weakly alkaline, which will not corrode the gills. It exhibits lower biological toxicity and corrosiveness in the aquatic environment, making it safer in aquatic applications. Thus, the water quality improver of this invention has multiple functions such as detoxification, water stabilization, deodorization, bottom quality improvement and fish and shrimp survival rate improvement. More importantly, the core efficacy of the water quality improver of this invention stems from the synergistic effect of its components, rather than the simple superposition of individual components. Specifically, sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate are compounded in a specific ratio to form a main-effect system of "detoxification-nitrite reduction-ammonia nitrogen removal." The detoxifying agent (sodium thiosulfate and sodium carbonate) provides full-cycle safety assurance for this system through an "inhibition-scavenging" mechanism, eliminating the potential risks of trace hydrolysis products. The synergistic agent, through its "permeability promotion-buffering-chelation" function, comprehensively optimizes the action environment and reaction efficiency of the main-effect components, ensuring their full performance. Thus, the three systems of main effect, safety, and auxiliary components are deeply integrated and interconnected, jointly achieving the significant advancements in the efficiency, safety, and multifunctionality of the water quality improver of this invention. Therefore, the aquatic water quality improver of this invention has the advantages of high efficiency, safety, and multifunctionality, and can achieve synergistic removal of nitrite and ammonia nitrogen from aquaculture water, demonstrating high use value and promising application prospects.

[0025] (2) A key innovation of this invention lies in the specific ratio of compound sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate. Studies have shown that although sodium carboxymethyl pentathiocarbonate (containing a longer sulfur chain) has stronger denitrification and chelation functions, its toxicity is only one ten-thousandth that of sodium pentathiocarbonate. Sodium carboxymethyl trithiocarbonate has even lower toxicity, but its effect is limited when used alone. Through practical research, this invention has explored the optimal compound dosage that achieves the best balance between toxicity and water treatment effect. If the dosage of sodium carboxymethyl trithiocarbonate is too high, although the overall toxicity is reduced, the water purification efficiency is insufficient, making it difficult to achieve the ideal treatment effect; if the dosage of sodium carboxymethyl pentathiocarbonate is too high, the overall toxicity increases, the safety window for aquatic organisms narrows, and the risk of drug use increases. This invention achieves synergy between the carboxyl chelating groups and polysulfide chelating groups and polysulfide reducing groups in the two modified components in terms of space and efficiency through precise compounding. Under the premise of controlling toxicity within a safe range, it maximizes the comprehensive efficiency of simultaneous detoxification, nitrite reduction and ammonia nitrogen removal, making up for the shortcomings of existing technologies that cannot balance high efficiency and safety.

[0026] (3) In this invention, although the stability of sodium carboxymethyl polythiocarbonate is far superior to that of conventional polythiocarbonate, it will still undergo trace hydrolysis under acidic conditions and high temperature, as shown in formula (5), producing trace amounts of highly toxic hydrogen sulfide (H2S) and toxic carbon disulfide (CS2), posing a safety hazard. To this end, this invention has specially formulated a specific amount of antidote in the aquatic water quality improver. The antidote is composed of sodium thiosulfate and sodium carbonate. Sodium carbonate is used to create a weakly alkaline environment, inhibit acidic hydrolysis, and react with the generated CS2 to render it harmless, as shown in formula (6); sodium thiosulfate is the core antidote component, which undergoes a rapid displacement reaction with highly toxic H2S, converting it into stable and non-toxic sulfate and stable and low-toxic colloidal elemental sulfur, as shown in formula (7). If this antidote is lacking, the product may release toxic gases during storage or when exposed to adverse conditions, directly threatening the safety of farmed animals. Excessive use of antidotes can excessively increase the alkalinity of the system and introduce excessive salt, potentially causing drastic pH fluctuations and stressing aquatic animals. Adding only sodium thiosulfate is insufficient to effectively inhibit acidic hydrolysis and eliminate CS2 toxicity; adding only baking soda is ineffective in efficiently removing H2S produced by hydrolysis. Only a scientifically combined approach can form a complete defense and detoxification loop.

[0027]

[0028] (4) The aquatic water quality improver of the present invention is further compounded with a synergist composed of one or more of the following: chelating agents (such as disodium EDTA, sodium citrate), humates (such as potassium fulvate, sodium humate), and surfactants (such as AES, APG, CAB). From the perspective of overall comprehensive effect, the essential function of the synergist is: firstly, to regulate the interfacial tension and permeability of the water body, promote the uniform diffusion of the core active components (such as sodium carboxymethyl polythiocarbonate, detoxifier) ​​in the water body, and improve the efficiency of action. Secondly, as an auxiliary chelation and buffering system, it can pre-bind some interfering ions in the water body and buffer pH fluctuations, creating favorable conditions for the efficient action of the core components (such as sodium carboxymethyl polythiocarbonate, detoxifier). If the synergist is lacking, the action speed, uniformity and stability of the core components will be greatly reduced, and the overall efficiency will be significantly reduced. If used excessively, it may cause the chemical oxygen demand of the water body to increase unnecessarily, increase oxygen consumption, or excessively chelate the essential trace elements of the water body, thereby destroying the ecological balance.

[0029] (5) The aquatic water quality improver of this invention has the characteristics of multiple effects in one dose. It can remove nitrite and ammonia nitrogen simultaneously, and also has the advantage of rapid effect. The water quality can be significantly improved within 24 hours after application, and the effective degradation rate of nitrite in aquaculture water can reach more than 90.0% within 72 hours. Crucially, this product has extremely high safety while maintaining high efficiency. It does not harm fish, shrimp, crabs, algae and beneficial bacteria, and has strong stability. It can tolerate a wide range of pH changes and is widely applicable to freshwater and seawater aquaculture. Detailed Implementation

[0030] The present invention will be further described below with reference to specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0031] Unless otherwise specified, all materials and instruments used in the following examples are commercially available. Sodium carboxymethyl trithiocarbonate can be purchased or customized from Hubei XX Chemical Co., Ltd. Sodium carboxymethyl pentathiocarbonate can be purchased or customized from Hubei XX Biotechnology Co., Ltd. Alternatively, sodium pentathiocarbonate and sodium chloroacetate can be purchased and prepared by oneself according to chemical reaction equation (2).

[0032] Example 1 An aquatic water quality improver of the present invention comprises the following raw material components by mass percentage: Sodium carboxymethyl sodium trithiocarbonate 3%, Sodium carboxymethyl sodium pentathiocarbonate 12%, Sodium thiosulfate (i.e., sodium thiosulfate) 2%, Sodium carbonate (i.e., baking soda) 2%, Sodium fatty alcohol polyoxyethylene ether sulfate (AES) 1%, Alkyl glycoside (APG) 1%, Water content: 79%.

[0033] The preparation method of the aquatic water quality improver in this embodiment, with the components used according to the above formula, includes the following steps: (1) First add water to the mixing tank, turn on the stirring, add sodium thiosulfate and baking soda to the tank and stir until completely dissolved to obtain the antidote solution; (2) Sodium monocarboxymethyl sodium trithiocarbonate and sodium monocarboxymethyl sodium pentathiocarbonate are slowly added to the antidote solution obtained in step (1) to obtain a mixed solution; (3) Add surfactants AES and APG to the mixed solution obtained in step (2), stir at room temperature and pressure for 60 minutes, stir until a light yellow transparent liquid is formed, let stand for 2 hours, filter, and dispense (500 mL of product) to obtain the aquatic water quality improver product.

[0034] The application method of the aquatic water quality improver in the treatment of aquaculture water in this embodiment is as follows: For aquaculture water bodies, use 100mL of the aquatic water quality improver product of this embodiment at a water depth of 1 meter per acre. Dilute with pond water before use and sprinkle throughout the pond. Use on a sunny morning. Before use, the nitrite content in the pond water was 0.06ppm. After use, the nitrite content in the water body was 0.005ppm 72 hours later, and the nitrite degradation rate was 91.7%.

[0035] Example 2 An aquatic water quality improver of the present invention comprises the following raw material components by mass percentage: Sodium carboxymethyl sodium trithiocarbonate 5%, Sodium carboxymethyl sodium pentathiocarbonate 10%, Sodium thiosulfate (i.e., sodium thiosulfate) 2%, Sodium carbonate (i.e., baking soda) 2%, Sodium fatty alcohol polyoxyethylene ether sulfate (AES) 1%, Alkyl glycoside (APG) 2%, Water content: 78%.

[0036] The preparation method of the aquatic water quality improver in this embodiment, with the components used according to the above formula, includes the following steps: (1) First add water to the mixing tank, turn on the stirring, add sodium thiosulfate and baking soda to the tank and stir until completely dissolved to obtain the antidote solution; (2) Sodium monocarboxymethyl sodium trithiocarbonate and sodium monocarboxymethyl sodium pentathiocarbonate are slowly added to the antidote solution obtained in step (1) to obtain a mixed solution; (3) Add surfactants AES and APG to the mixed solution obtained in step (2), stir at room temperature and pressure for 60 minutes, stir evenly until a light yellow transparent liquid is formed, let stand for 2 hours, filter, and dispense (fill 500ml of product) to obtain the aquatic water quality improver product.

[0037] The application method of the aquatic water quality improver in the treatment of aquaculture water in this embodiment is as follows: For aquaculture water bodies, use 200mL of the aquatic water quality improver product of this embodiment at a water depth of 1 meter per acre. Dilute with pond water before use and sprinkle throughout the pond. Use on a sunny morning. Before use, the nitrite content in the pond water was 0.08ppm. After 72 hours after use, the nitrite content in the water was 0.006ppm, and the nitrite degradation rate was 92.5%.

[0038] Example 3 An aquatic water quality improver of the present invention comprises the following components by mass percentage: Sodium carboxymethyl sodium trithiocarbonate 10%, Sodium carboxymethyl sodium pentathiocarbonate 10%, Sodium thiosulfate (i.e., sodium thiosulfate) 2%, Sodium carbonate (i.e., baking soda) 2%, Sodium fatty alcohol polyoxyethylene ether sulfate (AES) 1%, Alkyl glycoside (APG) 1%, Cocamidopropyl betaine (CAB) 1%, Water content: 73%.

[0039] The preparation method of the aquatic water quality improver in this embodiment, with the components used according to the above formula, includes the following steps: (1) First add water to the mixing tank, turn on the stirring, add sodium thiosulfate and baking soda to the tank and stir until completely dissolved to obtain the antidote solution; (2) Sodium monocarboxymethyl sodium trithiocarbonate and sodium monocarboxymethyl sodium pentathiocarbonate are slowly added to the antidote solution obtained in step (1) to obtain a mixed solution; (3) Add surfactants AES, APG and CAB to the mixed solution obtained in step (2), stir at room temperature and pressure for 60 minutes, stir evenly until a light yellow transparent liquid is formed, let stand for 2 hours, filter, and dispense (fill into 1000ml products).

[0040] The application method of the aquatic water quality improver in the treatment of aquaculture water in this embodiment is as follows: For aquaculture water bodies, use 250mL of the aquatic water quality improver product of this embodiment at a water depth of 1 meter per acre. Dilute with pond water before use and sprinkle throughout the pond. Use on a sunny morning. Before use, the nitrite content in the pond water is 0.10ppm. After 72 hours after use, the nitrite content in the water is 0.006ppm, and the nitrite degradation rate is 94.0%.

[0041] Table 1 - Comparison of the effects of aquatic water quality improvers in various embodiments

[0042] As shown in Table 1, the aquatic water quality improver of the present invention has high fish safety, good nitrite degradation effect and high ammonia nitrogen removal rate. Detailed analysis is as follows: (1) 96h fish Safety and toxicity comparison Example 1: 96h- =129.0 mg / L, slightly high toxicity.

[0043] Example 2: 96h- =131.5 mg / L, moderately toxic.

[0044] Example 3: 96h- =135.0mg / L has the lowest toxicity and high safety.

[0045] Toxicity ranking: Example 1 > Example 2 > Example 3.

[0046] Safety and friendliness: Example 3 > Example 2 > Example 1.

[0047] (2) Comparison of nitrite degradation rates Degradation capacity: Example 3 (94.0%) > Example 2 (92.5%) > Example 1 (91.7%) Reason: In Example 3, the total polysulfide content was the highest at 20%. With the addition of CAB+APG+AES for synergistic dispersion, the reaction was faster and the denitrification was more thorough, resulting in lower toxicity of the aquatic water quality improver.

[0048] (3) Comparison of ammonia nitrogen removal efficiency Example 3 (74.0%) is slightly better. The ammonia nitrogen removal rates of the three examples are not significantly different because the ammonia nitrogen removal rate is mainly related to pH adjustment with sodium carbonate and chelation with polythiocarbonates. The dosage of the antidote component is the same in the three examples, and the dosage of the synergist component differs little. When a strong effect is needed urgently to reduce ammonia nitrogen, the formulation of Example 3 is preferred.

[0049] In this embodiment, the purification effects of different dosages of sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate as aquaculture water conditioners on aquaculture water were also investigated, as follows: Referring to Example 2, keeping the amounts of other components and preparation steps unchanged, the amounts of sodium carboxymethyl sodium trithiocarbonate (denoted as a) and sodium carboxymethyl sodium pentathiocarbonate (denoted as b) were adjusted as follows: Table 2 - Comparison of the effects of aquatic water quality improvers prepared with different dosages of sodium trithiocarbonate and sodium carboxymethyl pentathiocarbonate

[0050] As can be seen from the effect data in Table 2, the present invention, through its component ratio design, can produce an aquatic water quality improver with high fish safety, high nitrite degradation rate, and good ammonia nitrogen removal effect. In actual research, the aquatic water quality improver of the present invention also has the following advantages: (1) The degradation time of nitrite and ammonia nitrogen can be further subdivided to match different breeding scenarios.

[0051] (1.1) The higher the proportion of a (trithiolated) a, the faster the denitrification and ammonia nitrogen reduction, making it suitable for emergency rescue of sudden nitrite explosions.

[0052] (1.2) b (pentasulfurized) proportion increases, denitrification and ammonia nitrogen reduction rate stabilize and slow down slightly, but long-term water stabilization time is longer, suitable for daily regular water adjustment and bottom stabilization of old ponds.

[0053] (1.3) Based on the data in Table 2, three types of formulas can be divided into emergency type, routine conditioning type and long-term bottom stabilizing type to meet the needs of different farmers.

[0054] (2) Clarify 96h- Safe concentration gradients are used to classify applicable aquaculture species.

[0055] (2.1) The increased proportion of b (pentathiocyanates) slightly increases the product's irritant properties. It will gradually decrease, and the safe concentration range will narrow.

[0056] (2.2) Based on the data comparison in Table 2, it is possible to accurately determine which group of sulfur-modified ratios are suitable for pure seedling shrimp, crab, adult fish farming, and special fish (such as California bass), so as to avoid stress-induced fish death.

[0057] In this embodiment, the purification effect of different dosages of aquatic water quality improvers on aquaculture water was also investigated, as follows: Referring to Example 2, keeping the amounts of other components and preparation steps unchanged, the amount of the antidote was adjusted as follows: Table 3 - Comparison of the effects of aquatic water quality improvers prepared with different antidote dosages

[0058] The data in Table 3 show that a dosage of 2% to 10% of the antidote has a better detoxification effect. In particular, when the dosage of the antidote is 2% to 6% and the mass ratio of sodium thiosulfate to sodium carbonate is 1 to 2: 1 to 3, an aquatic water quality improver that simultaneously ensures fish safety, nitrite degradation rate and ammonia nitrogen removal rate can be prepared.

[0059] Among them, when sodium thiosulfate is 2% and sodium bicarbonate is 2%, the safe concentration for fish is 96 h⁻¹. With a concentration of 131.0 mg / L, the water nitrite degradation rate is 90.5%, and the ammonia nitrogen removal rate is 74.0%. It is cost-effective and represents the optimal dosage for the antidote.

[0060] In this embodiment, the purification effect of aquatic water quality improvers with different dosages of synergistic adjuvants on aquaculture water was also investigated, as follows: Referring to Example 2, keeping the amounts of other components and preparation steps unchanged, the amount of synergistic agent was adjusted as follows: Table 4 - Comparison of the effects of aquatic water quality improvers prepared with different dosages of synergistic adjuvants

[0061] The data in Table 4 show that a small amount of synergistic agent results in insufficient synergistic effect, while a large amount increases costs and is not cost-effective. A synergistic effect is better when the synergistic agent is used at 2% to 5%. Furthermore, a synergistic agent used at 2% to 3% can better balance effect and cost.

[0062] The results above show that, compared with existing water quality improvers, the core component of the aquatic water quality improver of this invention is sodium carboxymethyl polythiocarbonate, specifically sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate. This component is prepared by organic modification of trithiocarbonate and pentathiocarbonate with carboxymethyl. On the one hand, through carboxymethylation modification, the toxicity of sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate can be significantly reduced, and the carboxymethyl group exhibits very high biocompatibility, similar to the low acute toxicity of carboxymethyl cellulose (CMC) in fish. >100mg / L, with less toxicity to aquatic animals in water. On the other hand, through carboxymethylation modification, the content of carboxyl chelating groups and polysulfide reducing groups in sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate can be significantly increased, and their water solubility and chelation efficiency are significantly better than ordinary polysulfide inorganic salts, and their stability is greatly improved, which can bring the following unexpected technical effects: (a) Utilizing the carboxyl chelating groups and polysulfide reducing groups in the carboxyl methyl (-COO) group - ) and polysulfides (-S x- (a) Through the double chelation effect of polysulfide groups, the reducing properties of polysulfide ions in polysulfide reducing groups are utilized to efficiently reduce nitrite to harmless nitrogen gas, achieving rapid degradation of nitrite; (b) Through the interaction between carboxyl chelating groups and polysulfide reducing groups, the conversion and degradation of ammonia nitrogen are promoted through oxidation, complexation, and improvement of the microecology of aquatic bodies, effectively reducing the ammonia nitrogen content in water bodies; (c) Under the protection of carboxylmethyl groups, the stability of sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate can be significantly improved, and the stability of high-temperature sodium carboxymethyl trithiocarbonate can be improved. (d) Under warm and rainy weather conditions, it is not easily decomposed and will not form toxic or harmful gases; under the buffering effect of carboxymethyl, sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate have relatively lower chemical activity and milder pH value, and the pH value is close to neutral / weakly alkaline, which will not corrode the gills. It exhibits lower biological toxicity and corrosiveness in the aquatic environment, making it safer in aquatic applications. Thus, the water quality improver of this invention has multiple functions such as detoxification, water stabilization, deodorization, bottom quality improvement and fish and shrimp survival rate improvement. More importantly, the core efficacy of the water quality improver of this invention stems from the synergistic effect of its components, rather than the simple superposition of individual components. Specifically, sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate are compounded in a specific ratio to form a main system of "detoxification-nitrite reduction-ammonia nitrogen removal." The detoxifying agents (sodium thiosulfate and sodium carbonate) provide full-cycle safety assurance for this system through an "inhibition-scavenging" mechanism, eliminating the potential risks of trace hydrolysis products. The synergistic adjuvants, through their "permeability promotion-buffering-chelation" functions, comprehensively optimize the action environment and reaction efficiency of the main active component, ensuring its full performance. Thus, the three systems of main efficacy, safety, and auxiliary components are deeply integrated and interconnected, jointly achieving the significant advancements in the efficiency, safety, and multifunctionality of the water quality improver of this invention. Therefore, the aquatic water quality improver of this invention has the advantages of high efficiency, safety, and multifunctionality, and can achieve synergistic removal of nitrite and ammonia nitrogen from aquaculture water, demonstrating high use value and promising application prospects.

[0063] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall still fall within the protection scope of the technical solutions of the present invention.

Claims

1. An aquatic water quality improver, characterized in that, The aquatic water quality improver comprises the following raw material components by mass percentage: Sodium carboxymethyl trithiocarbonate 3%–20%; Sodium carboxymethyl pentathiocarbonate 5%–20%; Synergistic additives 2%–5%; Antidote 2%–10%; The remainder is water.

2. The aquatic water quality improver according to claim 1, characterized in that, The aquatic water quality improver comprises the following raw material components by mass percentage: Sodium carboxymethyl trithiocarbonate 3%–15%; Sodium carboxymethyl pentathiocarbonate 5%–15%; Synergistic additives 2%–3%; Antidote 2%–6%; The remainder is water.

3. The aquatic water quality improver according to claim 1, characterized in that, The antidote includes sodium thiosulfate and sodium carbonate, wherein the mass ratio of sodium thiosulfate to sodium carbonate is 1-2:1-3; the synergist is selected from one or more of chelating agents, humates and surfactants.

4. The aquatic water quality improver according to claim 3, characterized in that, The chelating agent is disodium EDTA and / or sodium citrate; the humate is potassium humate and / or sodium humate; and the surfactant is at least one of sodium fatty alcohol polyoxyethylene ether sulfate, alkyl glycoside, and cocamidopropyl betaine.

5. The aquatic water quality improver according to any one of claims 1 to 4, characterized in that, The mass ratio of sodium carboxymethyl trithiocarbonate to sodium carboxymethyl pentathiocarbonate is 1-4:1-4.

6. The aquatic water quality improver according to claim 5, characterized in that, The carboxymethyl sodium trithiocarbonate is monocarboxymethyl sodium trithiocarbonate and / or dicarboxymethyl sodium trithiocarbonate; The carboxymethyl sodium trithiocarbonate includes at least one of sodium carboxymethyl sodium trithiocarbonate, potassium carboxymethyl sodium trithiocarbonate, magnesium carboxymethyl sodium trithiocarbonate, and calcium carboxymethyl sodium trithiocarbonate. The sodium carboxymethyl pentathiocarbonate is monocarboxymethyl sodium pentathiocarbonate and / or dicarboxymethyl sodium pentathiocarbonate; The carboxymethyl sodium pentathiocarbonate includes at least one of sodium carboxymethyl sodium pentathiocarbonate, potassium carboxymethyl sodium pentathiocarbonate, magnesium carboxymethyl sodium pentathiocarbonate, and calcium carboxymethyl sodium pentathiocarbonate.

7. A method for preparing an aquatic water quality improver as described in any one of claims 1 to 6, characterized in that, Includes the following steps: (1) Mix the antidote with water and dissolve it to obtain an antidote solution; (2) Add sodium carboxymethyl trithiocarbonate and sodium carboxymethyl pentathiocarbonate to the antidote solution obtained in step (1) to obtain a mixed solution; (3) Add the synergist to the mixed solution obtained in step (2), stir, let stand, filter, and obtain the aquatic water quality improver product.

8. The preparation method according to claim 7, characterized in that, In step (3), the stirring time is 60 to 90 minutes; the settling time is 2 to 4 hours.

9. The application of an aquatic water quality improver as described in any one of claims 1 to 6, or an aquatic water quality improver prepared by the preparation method described in claim 7 or 8, in the treatment of aquaculture water bodies.

10. The application according to claim 9, characterized in that, The application includes: using an aquatic water quality improver to purify aquaculture water, removing nitrite and ammonia nitrogen from the aquaculture water; the dosage of the aquatic water quality improver is 100mL to 400mL per acre of aquaculture water with a depth of 1 meter; the treatment time is 24h to 96h.

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