Calcium silicate composite scale cleaner and method

Abstract

The application discloses a kind of calcium silicate composite scale cleaning agent and method, belong to water pollution prevention and control technical field.The cleaning agent is water pollution prevention and control reagent material for calcium silicate composite scale control and removal, is composed of acidolysis, chelation dispersion, silicon complex, interface wetting penetration and auxiliary function component, is added to the circulating water of water treatment system, so that calcium silicate composite scale softens, dissociates and disperses into cleaning solution.Acidolysis component dissociates scale layer, chelation dispersion component and silicon complex component simultaneously constrain calcium and silicon in liquid phase with dissolved silicon, inhibit the secondary generation of colloidal silicon and make the scale removal more thoroughly, while less damage to equipment.The application collects cleaning state data by intelligent sensor group, controls dosing, circulation and end point by industrial controller according to normalized cleaning state index, to avoid excessive cleaning.

Description

Technical Field

[0001] This invention belongs to the field of water pollution prevention and control technology, and particularly relates to a calcium silicate composite scale cleaning agent and method. Background Technology

[0002] In water treatment systems of industries such as power and chemicals, adding water pollution control agents can soften water, prevent scale formation, or remove existing scale. For example, in reverse osmosis and nanofiltration water treatment systems, the feed water is continuously concentrated within the system during long-term operation. Calcium ions, silicates, carbonates, and sulfates in the water precipitate and deposit on surfaces in contact with the water, forming a complex scale mainly composed of calcium silicate, accompanied by carbonates, sulfates, silica, and iron-aluminum-silicon compounds. This type of complex scale has a dense structure and is insoluble in acids and alkalis of normal concentrations. Once formed, it causes a decrease in the water production of the water treatment system, an increase in operating resistance, and a deterioration in the quality of the produced water. Therefore, it is necessary to control and remove the scale by adding descaling water pollution control agents to the circulating water of the system.

[0003] In existing technologies, water pollution control agents used to remove calcium silicate complex scale are mostly high-concentration inorganic strong acids. However, adding such agents to water for descaling has several shortcomings. Strong acids are highly corrosive to membranes and metal surfaces in contact with water, easily damaging equipment while removing scale. After strong acids dissociate silicon in the scale, the silica easily condenses into colloidal silicon under acidic conditions and undergoes secondary deposition, forming new, difficult-to-remove pollutants, resulting in incomplete descaling. Existing descaling agents mainly rely on single scale-dissolving or scale-inhibiting / dispersing effects, lacking methods to simultaneously constrain dissolved calcium and silicon. The descaling process is prone to partial reversibility due to the recombination of products, leading to insufficient descaling. Current descaling processes relying on manual sampling and experience-based judgment to control dosage and endpoint determination lack objectivity, easily resulting in insufficient or over-treatment. Furthermore, there is a lack of corresponding treatment for the wastewater generated after treatment, making it difficult to control the pollution load of the wastewater.

[0004] Therefore, there is a need for a water pollution control agent and its application method that can completely remove calcium silicate complex scale under mild conditions, inhibit secondary colloidal pollution, be equipment-friendly, have a controllable dosing process, and reduce the volume of waste liquid. Summary of the Invention

[0005] To solve the above problems, the technical solution of the present invention is as follows: a calcium silicate composite scale cleaning agent, wherein the total amount of components is 1000 parts by mass, and the demineralized water is added to make up the balance to 1000 parts. The parts of polyepoxysuccinic acid, sodium polyaspartate, tetrasodium diacetate of glutamic acid, and polydimethyldiallyl ammonium chloride are based on the content of active ingredients. The cleaning agent is composed of group A, group B, group C, group D, and auxiliary functional components.

[0006] Group A, acid hydrolysis components: 50-120 parts of methanesulfonic acid, 20-60 parts of glycolic acid, and 10-40 parts of L-malic acid;

[0007] Group B, chelated and dispersed components: 10-40 parts of tetrasodium glutamate diacetate, 5-20 parts of trisodium methylglycine diacetate, 10-30 parts of polyepoxysuccinic acid, and 5-20 parts of sodium polyaspartate.

[0008] Group C, silicon complex components: D-sorbitol 10-40 parts, sodium gluconate 5-20 parts, D-mannitol 5-20 parts;

[0009] Group D, components for interface wetting and scale / fracture penetration: sodium dioctyl sulfosuccinate 2-10 parts, decyl glucoside 2-10 parts;

[0010] Auxiliary functional components: 1-5 parts benzimidazole, 2-8 parts polydimethyldiallylammonium chloride, and 30-80 parts glycerol.

[0011] Furthermore, by mass fraction, Group A consists of 80 parts methanesulfonic acid, 40 parts glycolic acid, and 20 parts L-malic acid; Group B consists of 25 parts tetrasodium glutamate diacetate, 10 parts trisodium methylglycine diacetate, 20 parts polyepoxysuccinic acid, and 10 parts sodium polyaspartate; Group C consists of 25 parts D-sorbitol, 10 parts sodium gluconate, and 10 parts D-mannitol; Group D consists of 5 parts sodium dioctyl sulfosuccinate and 5 parts decyl glucoside; the auxiliary functional components are 3 parts benzimidazole, 4 parts polydiallyl ammonium chloride, and 50 parts glycerol, with the demineralized water to be made up to 1000 parts.

[0012] Furthermore, the mass ratio of the acid hydrolysis component in group A to the chelate dispersion component in group B is 1.8–2.5:1; the mass ratio of the sum of tetrasodium glutamate diacetate and trisodium methylglycine diacetate in group B to the sum of polyepoxysuccinic acid and sodium polyaspartate is 1–2:1; and the mass ratio of the silicon complex component in group C to the chelate dispersion component in group B is 0.5–1.5:1.

[0013] Furthermore, the cleaning agent is prepared by the following steps:

[0014] H1. Take 60% to 70% of the total demineralized water, first add polyepoxysuccinic acid and sodium polyaspartate from group B and stir until hydrated and dissolved, then add tetrasodium glutamate diacetate and trisodium methylglycine diacetate and stir until dissolved to obtain the base solution of group B.

[0015] H2. Add D-sorbitol, sodium gluconate and D-mannitol from group C to group B base solution and stir until dissolved to obtain intermediate solution containing silicon complex component;

[0016] H3. Sodium dioctyl sulfosuccinate and decyl glucoside from group D are premixed with glycerol and benzimidazole from the auxiliary functional components to obtain a predispersed phase, which is then added to the intermediate liquid obtained in step H2 and stirred evenly.

[0017] H4. Under temperature control and online turbidity monitoring, the methanesulfonic acid, glycolic acid and L-malic acid of group A are added to the liquid obtained in step H3 in batches. After each batch is added, the turbidity of the material is no greater than 10 NTU and the pH change is no greater than 0.05 within 10 minutes before adding the next batch to obtain an acidified mixture.

[0018] H5. Add polydimethyldiallyl ammonium chloride, an auxiliary functional component, to the acidified mixture, add demineralized water, stir evenly, and filter through a 5μm pore size filter to obtain the cleaning agent.

[0019] Furthermore, in step H1, the stirring and dissolving temperature is 30–40°C; in step H4, the kettle temperature is controlled to be no higher than 35°C, and the acid hydrolysis component of group A is added in 3–5 batches; in step H5, after adding polydimethyldiallyl ammonium chloride, the material is monitored with an online pH meter, conductivity meter, and turbidity meter. When the pH change is no greater than 0.05, the conductivity change is no greater than 1%, and the turbidity change is no greater than 1 NTU within 10 minutes, the readings are considered stable. Deionized water is added to correct the total content of effective substances according to the density or refractive index calibration curve. Then, vacuum degassing is performed at -0.06 to -0.09 MPa for 5–20 minutes to obtain a uniform, clear, and non-stratified cleaning agent with a turbidity of no more than 10 NTU and no visible suspended matter.

[0020] This invention also provides a water treatment cleaning method for calcium silicate complex scale, comprising the following steps:

[0021] S1, Preparation of cleaning solution: The cleaning agent is added to water and diluted and mixed to obtain a cleaning solution;

[0022] S2, Immersion and Permeation: Fill the reverse osmosis or nanofiltration water treatment system to be cleaned with cleaning solution and let it stand to soak, so as to obtain a softened scale layer after immersion.

[0023] S3, Circulation and Dissociation: Drive the cleaning fluid to circulate in the water treatment system and collect cleaning status data. Based on the cleaning status data, add reagents, adjust the circulation intensity and switch the cleaning stage to dissociate, peel off and suspend the calcium silicate complex scale in the cleaning fluid, and obtain cleaning waste liquid containing calcium and soluble silicon.

[0024] S4, Endpoint Determination and Drainage: After determining the cleaning endpoint based on the cleaning status data, the cleaning waste liquid is discharged and reduced in volume.

[0025] S5, Rinse and Reset: Introduce reverse osmosis permeate or demineralized water into the system for replacement rinsing, so that the water treatment system is reset to the state of producing water or producing water operation.

[0026] Furthermore, in step S1, the cleaning agent is diluted 3 to 8 times by mass or volume to prepare a cleaning solution with a pH of 1.5 to 3.0; in step S2, the soaking time is 30 to 120 minutes; in step S3, the temperature of the cleaning solution is 25 to 35°C, and the circulation pressure is not greater than 0.3 MPa; in a water treatment system with a reverse circulation pipeline, the cleaning solution is periodically switched between forward and reverse flow; in a water treatment system without a reverse circulation pipeline, segmented circulation, pulse circulation, or intermittent soaking is used.

[0027] Furthermore, in step S3, the cleaning status data is collected through a smart sensor group. The smart sensor group includes a pH sensor, a temperature sensor, and a conductivity sensor located in the cleaning fluid loop; a turbidity sensor, a calcium ion detector, and a soluble silica detector located at the return port of the cleaning water tank; and a membrane differential pressure sensor, a circulation flow sensor, and a liquid level sensor located at the inlet and outlet of the water treatment system. The calcium ion detector and the soluble silica detector are bypass automatic sampling detectors equipped with filtration, dilution, temperature compensation, and two-point calibration modules. Calcium ions are determined using an ion-selective electrode method or a colorimetric method, and soluble silica is determined using a silicomolybdenum blue colorimetric method. The sampling cycle is 5–15 minutes.

[0028] Furthermore, the cleaning status data is sent to an industrial controller, which collects pH, temperature, pressure difference across the membrane, circulation flow rate, liquid level, and turbidity data at 5-60s intervals, and calcium ion concentration and soluble silica concentration data at 5-15min intervals. The industrial controller performs temperature compensation and moving average filtering on the data. It also calculates the calcium silicate dissolution rate, pressure differential load, turbidity load, pH deviation, and flow rate deviation, and calculates the normalized cleaning status index using the following formula. :

[0029] ;

[0030] In the formula, The normalized cleaning state index has a value of 0 to 1. , , , , These are weighted coefficients, and the sum of the five is 1. This is the normalized value of the pressure difference across the membrane relative to the initial pressure difference; The calcium-silicon dissolution rate is a normalized value relative to a preset dissolution rate threshold. The calcium-silicon dissolution rate is the increment of the sum of the calcium ion mass concentration and the soluble silicon mass concentration in two consecutive samples divided by the sampling interval. This is the normalized value of the cleaning fluid turbidity relative to a preset turbidity threshold. This is the normalized deviation of the real-time pH value of the cleaning solution from the set pH value. This is the normalized deviation of the circulating flow rate from the set circulating flow rate; , , , and All are quantities between 0 and 1;

[0031] When the real-time pH value of the cleaning solution is 0.1 to 0.3 higher than the set pH value, and When the amount exceeds the preset replenishment threshold, the industrial controller activates the reagent replenishment pump for intermittent replenishment. After each replenishment, the reagent is circulated and mixed for 5-10 minutes, and the calculation is recalculated. ;when When the system pressure exceeds the preset enhanced circulation threshold and is no greater than 0.3 MPa, the industrial controller increases the cleaning pump frequency or switches between forward and reverse circulation valves; when When the pH value is below the preset endpoint threshold, the industrial controller switches to the drainage and rinsing stage. When the pH value of the cleaning solution is below 1.5, the temperature is above 35°C, the system pressure is above 0.3MPa, the liquid level is below the safe liquid level, or the sensor signal is abnormal, the industrial controller reduces the cleaning pump frequency, stops the chemical replenishment pump, and executes a shutdown alarm.

[0032] Furthermore, in step S4, when in two consecutive samplings with an interval of 10-15 minutes, the relative increase in calcium ions and the relative increase in soluble silica in the cleaning waste liquid are both no greater than 5%, the pH drift of the cleaning liquid is no greater than 0.1, the turbidity growth rate is no greater than 3%, and the recovery rate of the pressure difference across the membrane in the water treatment system is no less than 80% or the recovery rate of the permeate flux is no less than 85%, the cleaning endpoint is determined to have been reached. The volume reduction treatment involves adjusting the discharged cleaning waste liquid to pH 9.5-11.0, adding magnesium salt and lime slurry at a magnesium ion to soluble silica molar ratio of 1-3:1, and adding iron salt or aluminum salt coagulant. After settling for 20-60 minutes, the liquid is filtered through a filter with a pore size of no more than 10 μm to reduce the concentration of soluble silica and calcium ions in the clear liquid to the influent limit of the subsequent discharge or reuse treatment unit.

[0033] The beneficial effects of this invention are as follows:

[0034] This invention integrates an acid hydrolysis component, a chelating and dispersing component, a silicon complexing component, an interfacial wetting and penetrating component, and auxiliary functional components into a single water pollution control agent material. These components work synergistically. The acid hydrolysis component dissociates calcium silicate composite scale, releasing calcium ions and silicic acid. The chelating and dispersing component chelates the released calcium ions, stabilizing the scale particles. The silicon complexing component stabilizes the released silicic acid. The interfacial wetting and penetrating component allows the agent to penetrate the micro-cracks and bottom of the scale layer. Both the calcium and silicon components of the scale are simultaneously removed from the liquid phase. The dissolution equilibrium of calcium silicate continuously moves towards dissociation, allowing for relatively thorough removal of dense calcium silicate composite scale even under relatively mild conditions. The degree of scale removal and the dissolution rate are superior to solutions relying solely on acid hydrolysis or dispersion.

[0035] The silicon complexing component of this invention forms a complex with the silicic acid monomer through adjacent hydroxyl groups on its polyol molecule. This stabilizes the dissociated silicic acid in the cleaning solution in a complexed form, preventing it from condensing into colloidal silica. This inhibits the secondary formation of colloidal silica and its redeposition on the membrane surface, which is prone to occur during the cleaning process. It also avoids incomplete cleaning caused by secondary contamination from colloidal silica during strong acid cleaning. This invention uses organic acids instead of inorganic strong acids and incorporates metal corrosion inhibitors, resulting in less damage to the reverse osmosis membrane, nanofiltration membrane, and stainless steel components while removing scale. The permeability and desalination performance of the membrane are maintained. The charge-regulating component of this invention adjusts the surface charge between the detached scale particles and the membrane surface, promoting scale desorption and inhibiting its redeposition. This results in a cleaner membrane surface after cleaning, restoring the permeate and desalination performance of the membrane system after cleaning.

[0036] The preparation method of this invention employs a feeding sequence of first hydrating and dissolving the polymer, then sequentially introducing the silicon complex component and the interface wetting and penetrating component, followed by batch-wise and temperature-controlled acid addition, and finally adding the cationic charge-regulating component, supplemented by online monitoring and vacuum degassing. This feeding sequence and temperature control method prevent premature association between the positively charged components and the negatively charged polymer and surfactant, avoiding flocculation and turbidity of the multi-component system under acidic conditions. The resulting pharmaceutical material is uniform, clear, non-stratified, and storage-stable.

[0037] The cleaning method of this invention incorporates soaking and penetration, cyclic dissociation, endpoint determination, and rinsing and repositioning of the tissue as a controlled process. It collects cleaning status data through an intelligent sensor array, and the industrial controller normalizes and weights the status quantities of different dimensions into a single cleaning status index. Based on this index, it triggers the addition of reagents, enhanced circulation, and endpoint switching in different zones, and performs safety interlocks under abnormal operating conditions. The control is automatically performed based on the real-time status, avoiding insufficient or excessive cleaning. Attached Figure Description

[0038] Figure 1 This is a flowchart of a water treatment and cleaning method for calcium silicate composite scale according to the present invention. Detailed Implementation

[0039] The technical solutions of this invention will be clearly and completely described below. In addition, the forms of the various structures described in the following embodiments are merely illustrative. This invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0040] The calcium silicate composite scale cleaning agent of this invention is a water pollution control agent material used for the control and removal of calcium silicate composite scale in reverse osmosis or nanofiltration water treatment systems. It is added to the circulating cleaning water of the water treatment system, transforming the dense deposited calcium silicate composite scale on the water-contacting surfaces into a complexable, peelable, and suspended state, allowing it to migrate into the cleaning solution. The calcium silicate composite scale refers to a mixed scale layer formed during the concentration process of a reverse osmosis or nanofiltration system, consisting primarily of calcium silicate, accompanied by calcium carbonate, calcium sulfate, silica, and iron-aluminum-silicon compounds, formed on the membrane surface and in the flow channels due to the deposition of calcium ions, silicates, carbonates, and sulfates in the water. This type of scale layer is insoluble in acids and alkalis of conventional concentrations. When using high-concentration strong acids for cleaning, on the one hand, the acid causes significant corrosion to the membrane and metal components; on the other hand, the dissociated silica monomers rapidly condense into colloidal silica under acidic conditions and are re-deposited onto the membrane surface, forming secondary pollution that is difficult to remove. This invention does not rely on high-concentration strong acids, but instead constructs a multi-element system that combines acid hydrolysis, chelation dispersion, silicon complexation, interface wetting and penetration, charge regulation and metal corrosion inhibition. Under mild conditions, the calcium ions and silicate monomers at both ends of the calcium silicate composite scale dissolution equilibrium are simultaneously removed from the liquid phase, so that the dissolution of the scale layer continues in the direction of dissociation, and the regeneration of colloidal silica is inhibited from the source.

[0041] The cleaning agent comprises chemical materials in parts by weight, with a total component quantity based on 1000 parts, and deionized water used to make up the remainder to 1000 parts. The parts of polyepoxysuccinic acid, sodium polyaspartate, tetrasodium glutamate diacetate, and polydimethyldiallyl ammonium chloride are based on their active ingredient content. The reason for using active ingredient content for these components is that commercially available products are often aqueous solutions with varying solid contents or different salt forms. If calculated based on the quantity of the product, repeated formulations would result in deviations due to differences in the active ingredients. Using active ingredient content ensures consistent results across different batches of raw materials. The cleaning agent consists of groups A, B, C, D, and auxiliary functional components.

[0042] Group A consists of acid-dissolving components, including methanesulfonic acid, glycolic acid, and L-malic acid, preferably 50–120 parts methanesulfonic acid, 20–60 parts glycolic acid, and 10–40 parts L-malic acid. Methanesulfonic acid is a high-strength, low-corrosive organic sulfonic acid that provides an acidic environment for the system and dissolves the carbonate and calcium silicate matrix in the scale layer, allowing calcium to enter the liquid phase in ionic form. Glycolic acid, also known as glycolic acid, is a monobasic organic acid containing hydroxyl groups, possessing both scale-dissolving and weak calcium-chelating effects. L-malic acid is a dibasic organic acid containing hydroxyl groups; its hydroxyl and carboxyl groups can form stable chelate rings with calcium ions. The combination of these three components in Group A provides the acidity required for scale removal and, through the auxiliary complexation of the hydroxyl acids, reduces the recombination of dissolved calcium ions, creating conditions for the subsequent action of Groups B and C.

[0043] Group B consists of chelating and dispersing components, including tetrasodium glutamate diacetate, trisodium methylglycine diacetate, polyepoxysuccinic acid, and sodium polyaspartate. Preferably, tetrasodium glutamate diacetate comprises 10–40 parts, trisodium methylglycine diacetate 5–20 parts, polyepoxysuccinic acid 10–30 parts, and sodium polyaspartate 5–20 parts. Tetrasodium glutamate diacetate (GLDA) and trisodium methylglycine diacetate (MGDA) are both biodegradable aminopolycarboxylic acid salt chelating agents derived from amino acids. They have a strong chelating capacity for calcium ions. In areas where acid is consumed and pH rises during scale dissociation, their calcium capture effect is enhanced, thereby stabilizing the dissolved calcium ions in the liquid phase. Polyepoxysuccinic acid (PESA) and sodium polyaspartate (PASP) are both phosphorus-free, green polycarboxylic acid scale inhibitors and dispersants. They inhibit the recrystallization and deposition of dissolved components through adsorption on scale microcrystals and film surfaces, lattice distortion, and particle dispersion, while ensuring stable suspension of detached scale particles in the cleaning solution. Group B combines small-molecule chelating agents with polymeric dispersants, balancing calcium chelation capacity with scale particle dispersion stability, avoiding the inadequacy of single-component solutions in acidic and high-hardness environments.

[0044] Group C is a silicon complexing component, comprising D-sorbitol, sodium gluconate, and D-mannitol, preferably 10-40 parts of D-sorbitol, 5-20 parts of sodium gluconate, and 5-20 parts of D-mannitol. D-sorbitol and D-mannitol are polyols containing multiple adjacent hydroxyl groups. Their ortho-hydroxyl groups can form polydentately coordinated silicon-polyol complexes with silicic acid monomers, allowing silicic acid to exist stably in the liquid phase in a complexed form and inhibiting the polymerization of silicic acid into colloidal silicon. Sodium gluconate is a polyhydroxycarboxylate, which, in addition to its complexing and stabilizing effect on silicic acid, also has an auxiliary chelating effect on calcium and iron ions. The role of Group C is to promptly complex and disperse the silicic acid released by acid decomposition, thus suppressing secondary contamination by colloidal silicon that easily occurs during strong acid cleaning in this system.

[0045] When Group A and Group C are used together, they produce a synergistic effect. Group A dissociates calcium silicate, releasing silica monomers. Without Group C, these silica monomers would condense and re-deposit under acidic conditions, making the dissolution process partially reversible. After the polyol in Group C complexes and stabilizes the silica monomers, the silica no longer re-precipitates. The dissolution of the scale layer changes from a reversible process to a continuous process moving towards dissociation. The degree of scale removal and silica removal is higher than the simple superposition of the effects of the two alone. When Group B and Group C are used together, Group B chelates and disperses the dissolved calcium ions, while Group C complexes and disperses the dissolved silica. The two key components required for scale formation, calcium and silica, are simultaneously confined in the liquid phase. The re-nucleation of calcium silicate lacks an ion source, and the anti-secondary scaling effect is significantly stronger than the effect of either component alone. When groups A, B, and C are combined, according to Le Chatelier's principle, calcium ions and silicate monomers at both ends of the dissolution equilibrium are continuously removed from the liquid phase, and the dissolution equilibrium of calcium silicate shifts towards dissociation. Therefore, a high degree of descaling can be achieved at a lower acid concentration, while the corrosion of the membrane and metal components is less. The three effects are superimposed to achieve a coordinated effect of high descaling, low secondary silica, and low corrosion.

[0046] Group D consists of components for interfacial wetting and scale / fracture penetration, including sodium dioctyl sulfosuccinate and decyl glucoside, preferably 2-10 parts each. Sodium dioctyl sulfosuccinate is a highly penetrating anionic surfactant that significantly reduces the surface tension of the cleaning solution, allowing the agent to penetrate along the micro-fractures of the scale layer into the root of the scale and the gaps on the membrane surface. Decyl glucoside is a biodegradable nonionic surfactant obtained by the condensation of fatty alcohol and glucose, exhibiting good wettability and membrane compatibility. The role of Group D is to improve the accessibility of the agent to dense scale layers, enabling the chemical action of Groups A, B, and C to reach the interior and bottom of the scale layer, rather than being limited to the scale surface.

[0047] The auxiliary functional components include benzimidazole, polydiallyl ammonium chloride, and glycerol, preferably 1-5 parts of benzimidazole, 2-8 parts of polydiallyl ammonium chloride, and 30-80 parts of glycerol, with the remainder made up with deionized water. Benzimidazole is a nitrogen-containing azole organic corrosion inhibitor, a non-ionic compound, slightly soluble in water but readily soluble in alcohols and polyols. The lone pair electrons of the unbonded nitrogen atom on its imidazole ring coordinate with the empty d orbitals of iron and chromium atoms on the stainless steel surface, chemically adsorbing on the metal surface and forming a dense organic adsorption film. This hinders the transfer of hydrogen ions to the metal matrix and the dissolution of metal ions, thereby reducing the corrosion of 316L stainless steel and other metal parts by acidic cleaning solutions. Benzimidazole does not contain phosphorus, sulfur, or molybdenum, does not chelate with dissociated calcium ions, and does not interfere with the determination of soluble silicon using the silicomolybdenum blue colorimetric method. Therefore, it is compatible with the chelating and dispersing components, silicon complexing components, and the acquisition of cleaning status data in this invention. Polydiallyl ammonium chloride (PDADMAC) is a cationic polyelectrolyte used in a low amount in this system. It serves as a charge control and micro-flocculation / stripping component, regulating the surface charge between the stripped scale particles and the membrane surface, promoting scale desorption and inhibiting redeposition. Because PDADMAC is positively charged, direct mixing with negatively charged polymers and surfactants in groups B and D easily leads to charge association and turbidity; therefore, it is used in a low amount in the formulation and added last during preparation. Glycerol, a polyhydroxy co-solvent, improves the compatibility of components and enhances the storage stability of the pharmaceutical materials. It also allows the slightly water-soluble benzimidazole to dissolve in glycerol before entering the system as a pre-dispersed phase. Deionized water is used as the solvent to avoid introducing new scale-forming ions.

[0048] In the preferred formulation, the mass ratio of the acid hydrolysis component in group A to the chelating and dispersing component in group B is preferably 1.8–2.5:1. This ratio ensures that the system has sufficient acidity for scale removal while retaining sufficient chelating and dispersing capacity. In group B, the mass ratio of the sum of tetrasodium glutamate diacetate and trisodium methylglycine diacetate to the sum of polyepoxysuccinic acid and sodium polyaspartate is preferably 1–2:1, which matches the effects of small molecule chelation and polymer dispersion. The mass ratio of the silicon complexing component in group C to the chelating and dispersing component in group B is preferably 0.5–1.5:1, which coordinates the complexing capacity of silicon with the chelating capacity of calcium. In a preferred embodiment, group A consists of 80 parts of methanesulfonic acid, 40 parts of glycolic acid, and 20 parts of L-malic acid; group B consists of 25 parts of tetrasodium glutamate diacetate, 10 parts of trisodium methylglycine diacetate, 20 parts of polyepoxysuccinic acid, and 10 parts of sodium polyaspartate; group C consists of 25 parts of D-sorbitol, 10 parts of sodium gluconate, and 10 parts of D-mannitol; group D consists of 5 parts of sodium dioctyl sulfosuccinate and 5 parts of decyl glucoside; the auxiliary functional components are 3 parts of benzimidazole, 4 parts of polydiallyl ammonium chloride, and 50 parts of glycerol; and the demineralized water is added to bring the total to 1000 parts.

[0049] Regarding the physical properties of the pharmaceutical materials, in a preferred embodiment, the weight-average molecular weight of polyepoxysuccinic acid is 400–1500, the weight-average molecular weight of sodium aspartate is 1000–5000, and the weight-average molecular weight of polydimethyldiallyl ammonium chloride is… Weight-average molecular weight refers to the polymer molecular weight obtained by weight-weighted averaging, and its value affects the polymer's adsorption and dispersion capacity and solution viscosity. The preferred pH of the pharmaceutical material at 25°C is 1.0–3.0, the preferred viscosity is 5–80 mPa·s, and the preferred surface tension is 25–45 mN·m. -1 The turbidity is preferably not greater than 10 NTU, and the density is preferably 1.05–1.25 g·cm³. -3 The solution showed no stratification or precipitation after being stored at -5 to 45°C for 30 days. To verify the compatibility of the reagent material with the membrane and metal, a cleaning solution diluted 3 to 8 times with the reagent material was contacted with a polyamide reverse osmosis membrane at 25 to 35°C for 16 to 24 hours. Changes in membrane mass loss, pure water flux retention, and desalination rate were observed. The corrosion rate of 316L stainless steel was measured under the same conditions. The optimal membrane mass loss rate was no greater than 0.5%, the pure water flux retention rate was no less than 90%, the desalination rate decreased by no more than 0.5 percentage points, and the corrosion rate was no greater than 0.5 mm·a. -1 .

[0050] The preparation method of the pharmaceutical material includes steps H1 to H5. The order of adding materials and the temperature control method in the preparation process are matched with the formulation composition to ensure the stability of the multi-component system and prevent stratification, flocculation, or premature gelation. In step H1, 60% to 70% of the formulation amount of deionized water is taken, and polyepoxysuccinic acid and sodium polyaspartate from group B are added first under stirring until they are fully hydrated and dissolved. Then, tetrasodium glutamate diacetate and trisodium methylglycine diacetate are added and stirred until completely dissolved to obtain the base solution of group B. Hydrifying and dissolving the polymer first can avoid polymer agglomeration and local insolubility. In step H2, D-sorbitol, sodium gluconate, and D-mannitol from group C are added to the base solution of group B and stirred until dissolved to obtain an intermediate solution containing silicon complex components. This allows the polyol to be fully dispersed before acidification so that the released silicic acid can be complexed at the beginning of acid hydrolysis. In step H3, sodium dioctyl sulfosuccinate and decyl glucoside from group D are pre-mixed with glycerol and benzimidazole from the auxiliary functional components to obtain a pre-dispersed phase, which is then added to the intermediate liquid obtained in step H2 and stirred evenly to allow the surfactant and corrosion inhibitor to enter the system uniformly in a pre-dispersed form.

[0051] In step H4, under temperature control and online turbidity monitoring, methanesulfonic acid, glycolic acid, and L-malic acid from group A are added in batches to the liquid obtained in step H3 to obtain an acidified mixture. Adding acid in batches and controlling the reactor temperature avoids excessively high local acidity that could cause polymer salting out or premature gelation of silicic acid. Preferably, the reactor temperature is controlled to be no higher than 35°C, and the acid-hydrolyzed components of group A are added in 3-5 batches. After each batch is added, the material turbidity is kept below 10 NTU, and the pH change is kept below 0.05 within 10 minutes before adding the next batch. The stability of turbidity and pH is used as the criterion for adding acid to the next batch, ensuring a smooth and controllable acid addition process. In step H5, polydimethyldiallyl ammonium chloride from the auxiliary functional components is added to the acidified mixture, and demineralized water is added to the total formulation amount. The mixture is stirred evenly and filtered through a 5 μm filter to obtain the pharmaceutical material. Adding polydimethyldiallyl ammonium chloride last, after the system has been acidified and stabilized, avoids premature association with anionic polymers and surfactants, which could lead to turbidity.

[0052] For quality control during preparation, the preferred temperature for stirring and dissolving in step H1 is 30–40°C. After adding polydimethyldiallyl ammonium chloride, the material is monitored using an online pH meter, conductivity meter, and turbidity meter. The readings are considered stable when the pH change is no greater than 0.05, the conductivity change is no greater than 1%, and the turbidity change is no greater than 1 NTU within 10 consecutive minutes. This serves as an objective criterion for uniform mixing, avoiding subjective judgment based on transparency. Subsequently, demineralized water is added to correct the total active ingredient content according to the density or refractive index calibration curve. The density or refractive index calibration curve refers to the pre-determined correspondence between the density or refractive index of the pharmaceutical material and the active ingredient content, which allows the active ingredient content of the material to be corrected to the target value. Then, vacuum degassing is performed at -0.06 to -0.09 MPa for 5–20 minutes to obtain a uniform, clear, and non-stratified pharmaceutical material with a turbidity of no more than 10 NTU and no visible suspended matter. Vacuum degassing is used to remove air bubbles introduced during the stirring process. Removing air bubbles is beneficial for the stability of pharmaceutical materials and the accurate detection of turbidity.

[0053] The water treatment cleaning method for calcium silicate complex scale described in this invention uses the above-mentioned reagent material, which is added to the circulating cleaning water of a reverse osmosis or nanofiltration water treatment system to soften, dissociate, and disperse the calcium silicate complex scale in the system. Figure 1 As shown, it includes steps S1 to S5.

[0054] Step S1 involves preparing the cleaning solution by diluting and mixing the reagent material in water. This step can be further divided into steps S11 to S13. In step S11, reverse osmosis permeate or demineralized water is added to the cleaning tank as the solution preparation water. Using reverse osmosis permeate or demineralized water avoids the introduction of new scale-forming ions. In step S12, the reagent material is added to the cleaning tank, preferably diluted 3 to 8 times by mass or volume, and the pH of the cleaning solution is adjusted to 1.5 to 3.0. In step S13, the stirrer or circulation pump is turned on to mix the reagent material and water evenly, obtaining the cleaning solution.

[0055] Step S2 involves soaking and permeation, filling the reverse osmosis or nanofiltration water treatment system to be cleaned with cleaning solution and allowing it to stand and soak, resulting in a softened scale layer. This step can be further divided into steps S21 and S22. In step S21, the valves of the water treatment system are adjusted to the cleaning state, and the cleaning solution is pumped into the membrane housing and flow channels of the system until they are full. In step S22, the pump is stopped, and the cleaning solution is allowed to stand and soak in the system, preferably for 30 to 120 minutes. During the soaking process, the interfacial wetting and scale fissure penetration components in the reagent material allow the cleaning solution to penetrate into the microfissures of the scale layer, and the acid hydrolysis components begin to dissolve the scale layer, resulting in a softened scale layer. Soaking provides a wetted and partially softened scale layer for subsequent circulation and dissociation.

[0056] Step S3 involves circulating the cleaning fluid within the water treatment system and collecting cleaning status data. Based on this data, reagents are added, circulation intensity is adjusted, and cleaning stages are switched. This causes the calcium silicate composite scale to dissociate, peel off, and suspend and disperse in the cleaning fluid, resulting in a cleaning waste liquid containing calcium and soluble silica. This waste liquid can be further divided into steps S31 to S33. In step S31, the cleaning pump is started to circulate the cleaning fluid between the water treatment system and the cleaning tank. Preferably, the cleaning fluid temperature is 25–35°C and the circulation pressure is no greater than 0.3 MPa. In a water treatment system with a reverse circulation pipeline, the cleaning fluid is periodically switched between forward and reverse flow. In a water treatment system without a reverse circulation pipeline, segmented circulation, pulse circulation, or intermittent soaking is used. The circulating flow allows the dissociated and peeled scale components to continuously migrate away from the scale layer and enter the cleaning fluid, reducing their redeposition on the membrane surface. In step S32, cleaning status data is collected during the circulation process. This data includes the pH, temperature, conductivity, turbidity, calcium ion concentration, soluble silica concentration of the cleaning solution, and the pressure difference across the membrane, circulation flow rate, and liquid level of the water treatment system. In step S33, based on the cleaning status data, reagent replenishment, circulation intensity adjustment, and cleaning stage switching are performed. When calcium and silica are still leaching from the cleaning solution, reagent materials are added and circulation is maintained, resulting in a cleaning waste liquid containing calcium and soluble silica.

[0057] The cleaning status data in step S3 is collected by an intelligent sensor group. This intelligent sensor group includes a pH sensor, a temperature sensor, and a conductivity sensor located in the cleaning fluid loop; a turbidity sensor, a calcium ion detector, and a soluble silica detector located at the return port of the cleaning water tank; and a membrane differential pressure sensor, a circulation flow sensor, and a liquid level sensor located at the inlet and outlet of the water treatment system. The calcium ion detector and the soluble silica detector are bypass automatic sampling detectors equipped with filtration, dilution, temperature compensation, and two-point calibration modules. They sample from the cleaning fluid loop, remove suspended solids by filtration, dilute as needed, and perform temperature compensation and two-point calibration before measurement. Calcium ions are measured using an ion-selective electrode method or a colorimetric method, and soluble silica is measured using a silicomolybdate blue colorimetric method. The sampling cycle is preferably 5–15 minutes. The ion-selective electrode method refers to the method of determining the concentration of a specific ion using an electrode that responds to that ion. The silicomolybdate blue colorimetric method refers to the method of determining the concentration of soluble silica by measuring the color intensity of the silicic acid reacting with molybdate to form a silicomolybdate heteropolyacid, which is then reduced to molybdenum blue. The system incorporates filtration, dilution, temperature compensation, and two-point calibration to reduce the interference of acidity, high turbidity, and complexing agents in the cleaning wastewater on the determination of calcium and silicon, thereby ensuring stable and reliable measurement results.

[0058] To facilitate understanding of the device's structure, the device includes a cleaning water tank, a cleaning pump, a chemical replenishment pump, a valve assembly, a membrane housing and membrane modules of a water treatment system, the aforementioned intelligent sensor assembly, an industrial controller, and a host computer. The cleaning water tank holds and prepares the cleaning solution. Its outlet is connected to the membrane housing inlet of the water treatment system via the cleaning pump and valve assembly. The membrane housing outlet returns to the cleaning water tank via the valve assembly, forming a circulation loop for the cleaning solution. The cleaning pump provides power for the circulation of the cleaning solution. The chemical replenishment pump's inlet is connected to a chemical material storage tank, and its outlet is connected to the cleaning water tank or the cleaning solution loop, used to replenish chemical materials to the circulating cleaning solution. The valve assembly includes a switching valve and a discharge valve located on the circulation loop. The switching valve is used to switch between forward and reverse circulation and to open and close each cleaning stage. The discharge valve is used to discharge cleaning waste liquid. The intelligent sensor assembly is located at the cleaning solution loop, the cleaning water tank return port, and the inlet and outlet of the water treatment system, as described above. Its output terminal is connected to the input terminal of the industrial controller via a signal line, sending the collected cleaning status data to the industrial controller in the form of an electrical signal. The industrial controller is a programmable logic controller (PLC) or edge controller. Its outputs are connected to the cleaning pump, chemical replenishment pump, and valve assembly via control lines. Based on cleaning status data, it sends control commands to these pumps to adjust the cleaning pump frequency, control the start / stop and dosage of the chemical replenishment pump, and control the switching of the valve assembly. A host computer communicates with the industrial controller to set operating parameters, record cleaning status data, and generate cleaning process curves and reports. The above units form a core circulation loop consisting of a cleaning water tank, cleaning pump, and membrane housing, supplemented by a detection and control loop consisting of intelligent sensor arrays, the industrial controller, and actuators. This combination ensures a controlled cleaning process, reducing the bias of human judgment.

[0059] The industrial controller controls the cleaning process as follows: It collects data on pH, temperature, pressure difference across the membrane, circulation flow rate, liquid level, and turbidity at 5-60 second intervals, and calcium ion concentration and soluble silica concentration at 5-15 minute intervals. The controller then applies temperature compensation and moving average filtering to the data. Temperature compensation refers to converting the measured value to a reference temperature based on the relationship between the measured value and temperature. Moving average filtering uses the average of the most recent samples as the current value to reduce random fluctuations. Different acquisition intervals are used for different quantities because pH, pressure difference, and flow rate can be obtained quickly and in real time, while calcium ions and soluble silica require bypass sampling and colorimetric determination, which have a longer acquisition period. Setting separate acquisition intervals ensures that each data point participates in control within its available timescale.

[0060] The industrial controller calculates the calcium-silicon leaching rate, differential pressure load, turbidity load, pH deviation, and flow rate deviation, and normalizes these quantities with different dimensions to values ​​between 0 and 1. Then, a weighted sum is obtained to obtain the normalized cleaning state index. Normalization refers to converting quantities of different dimensions and orders of magnitude into dimensionless quantities between 0 and 1 according to their reference values, making them comparable and weighted for summation. Normalization solves the problem that different physical quantities cannot be directly added due to differences in dimensions and orders of magnitude. The calcium-silicon leaching rate is calculated using the following formula.

[0061] ;

[0062] In the formula, Calcium and silicon dissolution rate (mg·L) -1 ·min -1 ); The sum of the calcium ion concentration and the soluble silica concentration in the cleaning wastewater at the time of sampling (mg·L) -1 ); This is the sum of the calcium ion concentration and the soluble silica concentration in the cleaning wastewater at the time of the last sampling (mg·L). -1 ); The time interval (min) between two consecutive samples.

[0063] Differential pressure load, dissolution load, turbidity load, pH deviation, and flow deviation are normalized according to the following formulas. The calculated values ​​are taken as 1 when they are greater than 1 and as 0 when they are less than 0, i.e., the range is limited to between 0 and 1. Differential pressure load is calculated according to the following formula.

[0064] ;

[0065] In the formula, For differential pressure load, it is a dimensionless quantity between 0 and 1; This represents the real-time pressure difference across the membrane (MPa). The target pressure difference across the membrane (MPa) is set. The initial pressure difference (MPa) before and after cleaning the membrane.

[0066] The dissolution load is calculated using the following formula.

[0067] ;

[0068] In the formula, Dissolution load is a dimensionless quantity between 0 and 1; Calcium and silicon dissolution rate (mg·L) -1 ·min -1 ); The preset calcium and silicon dissolution rate threshold (mg·L) -1 ·min -1 ).

[0069] Turbidity load is calculated using the following formula.

[0070] ;

[0071] In the formula, Turbidity loading is a dimensionless quantity between 0 and 1. Turbidity of the cleaning solution (NTU); The preset turbidity threshold (NTU) is used.

[0072] pH deviation is calculated using the following formula.

[0073] ;

[0074] In the formula, pH deviation is a dimensionless quantity between 0 and 1. For absolute value operations; The real-time pH value of the cleaning solution; To set the pH value; This is the preset pH deviation full scale.

[0075] The flow deviation is calculated using the following formula.

[0076] ;

[0077] In the formula, For flow deviation, it is a dimensionless quantity between 0 and 1; For absolute value operations; To set the circulation flow rate (m 3 ·h -1 ); Real-time circulating flow (m 3 ·h -1 ).

[0078] The industrial controller controls the cleaning pump frequency, valve switching, and chemical replenishment pump dosage based on the normalized cleaning state index calculated by the following formula.

[0079] ;

[0080] In the formula, The normalized cleaning state index is a dimensionless quantity between 0 and 1. , , , , These are weighted coefficients, and the sum of the five is 1. For differential pressure load; Dissolution load; Turbidity load; pH deviation; This is for flow rate deviation.

[0081] The industrial controller operates on a threshold-based zoning system, executing corresponding control actions based on the normalized cleaning state index (NDI) and its components. When the real-time pH of the cleaning solution is 0.1–0.3 higher than the set pH and the leaching load exceeds the preset replenishment threshold, the industrial controller activates the reagent replenishment pump for intermittent replenishment. After each replenishment, the solution is circulated and mixed for 5–10 minutes, and the NDI is recalculated. A pH rise indicates that the acid has been consumed and scale is still leaching; at this point, reagents are added to maintain the descaling effect. When the NDI is higher than the preset enhanced circulation threshold and the system pressure is not greater than 0.3 MPa, the industrial controller increases the cleaning pump frequency or switches between forward and reverse circulation valves to enhance mass transfer and accelerate scale removal and migration. When the NDI is lower than the preset endpoint threshold and the endpoint conditions are met, the industrial controller switches to the drainage and rinsing stage. When the cleaning solution pH is below 1.5, the temperature is above 35℃, the system pressure is above 0.3MPa, the liquid level is below the safe level, or the sensor signal is abnormal, the industrial controller reduces the cleaning pump frequency, stops the chemical replenishment pump, and executes a shutdown alarm. These safety interlocks are used to protect the membrane and equipment under abnormal operating conditions. By using a normalized cleaning state index in conjunction with threshold-based zone control, actions such as soaking, circulation, replenishment, enhanced circulation, and endpoint switching are performed automatically based on real-time status, reducing fluctuations caused by human experience-based judgment.

[0082] Step S4 is the endpoint determination and wastewater discharge. Based on the cleaning status data, after determining that the cleaning endpoint has been reached, the cleaning wastewater is discharged and subjected to volume reduction treatment. This can be further divided into steps S41 to S43. In step S41, the cleaning endpoint is determined to have been reached when, in two consecutive samples taken at an interval of 10-15 minutes, the relative increase in calcium ions and soluble silica in the cleaning wastewater is no greater than 5%, the pH drift of the cleaning solution is no greater than 0.1, the turbidity increase rate is no greater than 3%, and the pressure difference recovery rate before and after the membrane of the water treatment system is no less than 80% or the permeate flux recovery rate is no less than 85%. The stabilization of calcium and silica dissolution is used as an indicator that the scale has been basically removed, and the pressure difference recovery rate or flux recovery rate is used as an indicator that the membrane performance has been restored. The endpoint is determined when both conditions are met simultaneously, providing an objective basis for endpoint determination. In step S42, circulation is stopped and the cleaning wastewater is discharged. In step S43, the discharged cleaning wastewater is subjected to volume reduction treatment.

[0083] In step S43, the volume reduction treatment involves adjusting the pH of the discharged cleaning wastewater to 9.5–11.0, adding magnesium salt and lime slurry at a magnesium ion to soluble silica molar ratio of 1–3:1, and adding iron or aluminum salt coagulants. After settling for 20–60 minutes, the solution is filtered through a filter with a pore size no larger than 10 μm to reduce the concentration of soluble silica and calcium ions in the clarified liquid to the influent limit of the subsequent discharge or reuse treatment unit. After adjusting the wastewater to alkaline, magnesium salt is added. Magnesium ions generate magnesium hydroxide under alkaline conditions. Magnesium hydroxide has an adsorption and co-precipitation effect on silicic acid, which can transfer the soluble silica in the cleaning wastewater into the sludge. Lime slurry provides alkalinity and causes calcium to precipitate in the form of calcium carbonate or hydroxide. Iron or aluminum salt coagulants promote the aggregation and sedimentation of fine particles by generating hydroxide flocs. After sedimentation and filtration, the silicon and calcium in the waste liquid are separated into silicon-calcium sludge, and the pollution load of the clear liquid is reduced, so that the application of the agent material forms a closed loop from cleaning to waste liquid treatment, which is consistent with its positioning as a water pollution control agent material.

[0084] Step S5 is rinsing and resetting. Reverse osmosis permeable water or demineralized water is introduced into the system for displacement rinsing, resetting the water treatment system to the state of needing to produce water or operating with produced water. This can be further divided into steps S51 and S52. In step S51, reverse osmosis permeable water or demineralized water is introduced into the system for displacement rinsing, discharging residual cleaning solution and dissociation products from the system until the drainage meets the set requirements. In step S52, the system valves are reset to the state of needing to produce water or operating with produced water, restoring the water treatment system to operation.

[0085] Example 1: The calcium silicate composite scale cleaner of this example is a biodegradable water pollution control agent. Its total components are based on a mass ratio of 1000 parts, with demineralized water used to make up the remainder to 1000 parts. The parts of polyepoxysuccinic acid, sodium polyaspartate, tetrasodium diacetate of glutamic acid, and polydimethyldiallyl ammonium chloride are based on the active ingredient content. Active ingredient content refers to the mass fraction of the target compound that actually functions in the commercially available raw materials. The formulation of this embodiment is as follows: Group A acid hydrolysis component: 80 parts methanesulfonic acid, 40 parts glycolic acid, and 20 parts L-malic acid; Group B chelating and dispersing component: 25 parts tetrasodium diacetate of glutamic acid, 10 parts trisodium diacetate of methylglycine, 20 parts polyepoxysuccinic acid, and 10 parts sodium polyaspartate; Group C silicon complexing component: 25 parts D-sorbitol, 10 parts sodium gluconate, and 10 parts D-mannitol; Group D interface wetting and scale and crack penetration component: 5 parts sodium dioctyl sulfosuccinate and 5 parts decyl glucoside; auxiliary functional component: 3 parts benzimidazole, 4 parts polydimethyldiallylammonium chloride, and 50 parts glycerol; demineralized water is added to make up to 1000 parts, that is, the demineralized water is 683 parts.

[0086] Of the above components, tetrasodium glutamate diacetate (GLDA) and trisodium methylglycine diacetate (MGDA) are biodegradable amino polycarboxylic acid chelating agents derived from amino acids, used to chelate dissolved calcium ions. Polyepoxysuccinic acid (PESA) and sodium polyaspartate (PASP) are phosphorus-free polycarboxylic acid scale inhibitors and dispersants, used to disperse scale particles and inhibit their redeposition. Sodium dioctyl sulfosuccinate is a highly penetrating anionic surfactant, and decyl glucoside is a biodegradable nonionic surfactant; both are used to reduce the surface tension of the cleaning fluid and penetrate into the microcracks of the scale layer. Polydimethyldiallyl ammonium chloride (PDADMAC) is a cationic polyelectrolyte used as a charge control and micro-flocculation-stripping component. In this embodiment, the weight-average molecular weight of polyepoxysuccinic acid is 800, the weight-average molecular weight of sodium polyaspartate is 3000, and the weight-average molecular weight of polydimethyldiallyl ammonium chloride is... Weight-average molecular weight refers to the polymer molecular weight obtained by weighting by molecular weight, and is determined by the general method of gel permeation chromatography.

[0087] The pharmaceutical material is prepared according to steps H1 to H5. In step H1, approximately 444 parts of deionized water (65% of the formulation amount) are taken and, under stirring, polyepoxysuccinic acid and sodium polyaspartate are added first, and stirred until fully hydrated and dissolved. Then, tetrasodium glutamate diacetate and trisodium methylglycine diacetate are added, and stirred at 35°C until completely dissolved to obtain the B-group base solution. Hydrating and dissolving the polymer first can prevent its agglomeration and local insolubility. In step H2, D-sorbitol, sodium gluconate, and D-mannitol are added to the B-group base solution and stirred until dissolved to obtain an intermediate solution containing silicon complex components. This ensures that the polyol is evenly dispersed before acidification so that it can complex the released silicic acid at the beginning of acidolysis. In step H3, sodium dioctyl sulfosuccinate, decyl glucoside, glycerol, and benzimidazole are pre-mixed evenly to obtain a pre-dispersed phase, which is then added to the intermediate solution and stirred evenly. In step H4, under temperature control and online turbidity monitoring, methanesulfonic acid, glycolic acid, and L-malic acid are added in four batches. The reactor temperature is controlled to not exceed 35°C. After each batch is added, the material turbidity is not greater than 10 NTU and the pH change is not greater than 0.05 within 10 minutes before adding the next batch, resulting in an acidified mixture. Adding acid in batches and controlling the temperature can avoid excessive local acidity, which could cause polymer salting out or premature gelation of silicic acid. In step H5, polydimethyldiallyl ammonium chloride is added, and the remaining deionized water is added to bring the total to 1000 parts. The mixture is stirred evenly and degassed under vacuum at -0.08 MPa for 10 minutes. After filtration through a 5 μm filter, a uniform, clear, and non-stratified pharmaceutical material with a turbidity not greater than 10 NTU and no visible suspended matter is obtained. Adding polydimethyldiallyl ammonium chloride last can prevent it from prematurely associating with anionic polymers and surfactants, which would cause turbidity.

[0088] The cleaning agent material of this embodiment is used to clean calcium silicate composite scale in a reverse osmosis water treatment system. The cleaning method includes steps S1 to S5. Step S1 is to prepare the cleaning solution, which further includes steps S11 to S13. In step S11, reverse osmosis permeate water is added to the cleaning water tank. In step S12, the cleaning agent material is added and diluted 5 times by volume to make the pH of the cleaning solution 2.0. In step S13, the circulation pump is turned on to mix the cleaning agent material and water evenly to obtain the cleaning solution. Step S2 is immersion permeation, which further includes steps S21 to S22. In step S21, the valve is adjusted to the cleaning state and the cleaning solution is pumped into the membrane housing and flow channel to fill it. In step S22, the pump is stopped and the system is allowed to stand and soak for 60 minutes to obtain a softened scale layer. Step S3 is the cyclic dissociation, further including steps S31 to S33. In step S31, the cleaning pump is started to circulate the cleaning solution at a circulating pressure of 0.2 MPa at 30°C, periodically switching between forward and reverse flow. In step S32, the pH, temperature, conductivity, turbidity, calcium ion concentration, soluble silica concentration, pressure difference across the membrane, circulation flow rate, and liquid level of the cleaning solution are collected. In step S33, reagents are added and circulation is enhanced based on the data, resulting in a cleaning waste liquid containing calcium and soluble silica. Step S4 is the endpoint determination and discharge, further including steps S41 to S43. In step S41, the cleaning endpoint is determined. In step S42, the cleaning waste liquid is discharged. In step S43, the waste liquid is reduced in volume. Step S5 is the rinsing and resetting, further including steps S51 to S52. In step S51, reverse osmosis permeate water is introduced for replacement rinsing. In step S52, the valve is reset to the permeate water operating state.

[0089] In step S3, the cleaning status data is collected by the intelligent sensor group. Calcium ions are measured using the ion-selective electrode method, and soluble silicon is measured using the silicomolybdate blue colorimetric method. The ion-selective electrode method refers to the method of measuring the concentration of a specific ion using an electrode that responds to that ion. The silicomolybdate blue colorimetric method refers to the method of measuring the concentration of soluble silicon by the reaction of silicic acid with molybdate to form silicomolybdate heteropolyacid, which is then reduced to molybdenum blue and the concentration is determined by the color intensity. The sampling period for both is 10 minutes. In step S33, the industrial controller collects pH, temperature, pressure difference, flow rate, liquid level, and turbidity at a period of 10 seconds, and collects calcium ion and soluble silicon concentrations at a period of 10 minutes. After temperature compensation and moving average filtering of the data, the calcium and silicon dissolution rate is calculated using the following formula.

[0090] ;

[0091] In the formula, Calcium and silicon dissolution rate (mg·L) -1 ·min -1 ); The sum of the calcium ion concentration and the soluble silica concentration in the cleaning wastewater at the time of sampling (mg·L) -1 ); This is the sum of the calcium ion concentration and the soluble silica concentration in the cleaning wastewater at the time of the last sampling (mg·L). -1 ); The time interval (min) between two consecutive samples. At 1 hour of cleaning, the sum of calcium ions and soluble silica in this sample was 840 mg·L⁻¹. -1 The last time it was 80 mg / L -1 The sampling interval is 60 minutes. Substituting the values, we get... It is 12.67 mg·L -1 ·min -1 .

[0092] The industrial controller normalizes the pressure difference, dissolution rate, turbidity, pH deviation, and flow deviation to values ​​between 0 and 1, then weights and sums them to obtain a normalized cleaning state index. Normalization refers to converting quantities of different dimensions and orders of magnitude into dimensionless quantities between 0 and 1 according to their reference values. Each normalized quantity is set to 1 if the calculated value is greater than 1 and 0 if it is less than 0. In this embodiment, an initial pressure difference before and after the membrane is set. The pressure difference across the target membrane is 0.26 MPa. The threshold for calcium-silicon dissolution rate is 0.08 MPa. 5 mg·L -1 ·min -1 Turbidity threshold Set the pH value to 10 NTU. 2.0, pH deviation at full scale Set the circulation flow rate to 0.5. 20m 3 ·h -1 Weighting coefficients to The values ​​are 0.3, 0.3, 0.15, 0.15, and 0.1, respectively. The normalized cleaning state index is calculated using the following formula.

[0093] ;

[0094] In the formula, The normalized cleaning state index is a dimensionless quantity between 0 and 1. , , , , These are weighted coefficients, and the sum of the five is 1. For differential pressure load, it is equal to the difference between the real-time differential pressure across the membrane and the target differential pressure, divided by the difference between the initial differential pressure and the target differential pressure. The dissolution load is equal to the calcium-silicon dissolution rate divided by the dissolution rate threshold. The turbidity load is equal to the turbidity of the cleaning solution divided by the turbidity threshold. pH deviation is equal to the absolute value of the difference between the real-time pH value of the cleaning solution and the set pH value, divided by the full-scale pH deviation range. The flow deviation is calculated as the absolute value of the difference between the set circulation flow rate and the real-time circulation flow rate, divided by the set circulation flow rate. After 1 hour of cleaning, the pressure difference across the membrane was 0.20 MPa. It is 0.667. The amplitude limit is 1.0, and the turbidity is 2.5 NTU. The value was 0.25, and the real-time pH was 2.3. The value is 0.6, and the circulating flow rate is 19m³. 3 ·h -1 , The value is 0.05. Substituting it into the equation, we get... The pH value is 0.63. At this point, the pH of the cleaning solution is higher than the set value and the dissolution load is high. The industrial controller starts the reagent replenishment pump to replenish intermittently and increases the frequency of the cleaning pump to enhance the circulation. When the normalized cleaning state index drops below the preset endpoint threshold of 0.15 and meets the endpoint conditions described in step S41, the industrial controller switches to the drainage and rinsing stage.

[0095] In step S41, samples are continuously taken near the endpoint at intervals of 10 to 15 minutes. The endpoint is determined to have been reached when the relative increase in calcium ions and soluble silica between two consecutive samples is no greater than 5%, the pH drift of the cleaning solution is no greater than 0.1, the turbidity increase rate is no greater than 3%, and the membrane pressure difference recovery rate is no less than 80% or the permeate flux recovery rate is no less than 85%. In step S43, the volume reduction treatment involves adjusting the cleaning wastewater to pH 10.0, adding magnesium chloride and lime slurry at a magnesium ion to soluble silica molar ratio of 2:1, and adding polyferric sulfate coagulant. After settling for 40 minutes, the solution is filtered through a 10 μm filter. The soluble silica in the wastewater is adsorbed and co-precipitated by magnesium hydroxide under alkaline conditions, while calcium precipitates as calcium carbonate and hydroxide, resulting in silica-calcium sludge and treated water with reduced pollution load. The entire cleaning and wastewater treatment process forms a closed loop from cleaning to wastewater volume reduction, consistent with the positioning of the reagent material as a water pollution control agent.

[0096] Example 2 differs from Example 1 in that the formulation uses the lower limit of the dosage range described in this invention and the process parameters are adjusted accordingly. By mass parts, Group A consists of 50 parts methanesulfonic acid, 20 parts glycolic acid, and 10 parts L-malic acid; Group B consists of 10 parts tetrasodium glutamate diacetate, 5 parts trisodium methylglycine diacetate, 10 parts polyepoxysuccinic acid, and 5 parts sodium polyaspartate; Group C consists of 10 parts D-sorbitol, 5 parts sodium gluconate, and 5 parts D-mannitol; Group D consists of 2 parts sodium dioctyl sulfosuccinate and 2 parts decyl glucoside; the auxiliary functional components are 1 part benzimidazole, 2 parts polydimethyldiallylammonium chloride, and 30 parts glycerol, with demineralized water added to bring the total to 1000 parts. The weight-average molecular weight of polyepoxysuccinic acid is 400, the weight-average molecular weight of sodium polyaspartate is 1000, and the weight-average molecular weight of polydimethyldiallylammonium chloride is... In the preparation process, the acid hydrolysis component of group A was added in three batches in step H4, and in step H5, the solution was degassed under vacuum at -0.06 MPa for 5 min. During the cleaning process, the solution was diluted three times by volume in step S12 to achieve a pH of 1.5, and in step S22, it was allowed to stand and soak for 120 min. In step S31, the temperature of the cleaning solution was 25℃.

[0097] Example 3 differs from Example 1 in that the formulation uses the upper limit of the dosage range described in this invention and the process parameters are adjusted accordingly. By mass parts, Group A consists of 120 parts methanesulfonic acid, 60 parts glycolic acid, and 40 parts L-malic acid; Group B consists of 40 parts tetrasodium glutamate diacetate, 20 parts trisodium methylglycine diacetate, 30 parts polyepoxysuccinic acid, and 20 parts sodium polyaspartate; Group C consists of 40 parts D-sorbitol, 20 parts sodium gluconate, and 20 parts D-mannitol; Group D consists of 10 parts sodium dioctyl sulfosuccinate and 10 parts decyl glucoside; the auxiliary functional components are 5 parts benzimidazole, 8 parts polydimethyldiallyl ammonium chloride, and 80 parts glycerol, with demineralized water added to bring the total to 1000 parts. The weight-average molecular weight of polyepoxysuccinic acid is 1500, the weight-average molecular weight of sodium polyaspartate is 5000, and the weight-average molecular weight of polydimethyldiallyl ammonium chloride is... In the preparation process, the acid hydrolysis component of group A was added in 5 batches in step H4, and in step H5, the solution was degassed under vacuum at -0.09 MPa for 20 min. During cleaning, the solution was diluted 8 times by volume in step S12 to achieve a pH of 3.0, and in step S22, it was allowed to stand and soak for 30 min. In step S31, the temperature of the cleaning solution was 35℃.

[0098] Example 4 differs from Example 1 in that the formulation uses the middle value of the dosage range described in this invention. By mass parts, Group A consists of 100 parts methanesulfonic acid, 45 parts glycolic acid, and 25 parts L-malic acid; Group B consists of 30 parts tetrasodium glutamate diacetate, 12 parts trisodium methylglycine diacetate, 25 parts polyepoxysuccinic acid, and 13 parts sodium polyaspartate; Group C consists of 30 parts D-sorbitol, 12 parts sodium gluconate, and 14 parts D-mannitol; Group D consists of 8 parts sodium dioctyl sulfosuccinate and 6 parts decyl glucoside; the auxiliary functional components are 4 parts benzimidazole, 6 parts polydimethyldiallylammonium chloride, and 60 parts glycerol; and the deionized water is added to bring the total to 1000 parts. During cleaning, in step S12, the cleaning solution is diluted 6 times by volume to achieve a pH of 2.5; in step S22, it is allowed to stand and soak for 90 minutes; and in step S31, the cleaning solution temperature is 32°C.

[0099] Comparative Example 1 differs from Example 1 in that the formulation does not contain the group C silicon complex component, i.e., it does not contain D-sorbitol, sodium gluconate and D-mannitol. The missing parts are made up by demineralized water. The remaining components, preparation process and cleaning process are the same as those in Example 1.

[0100] Comparative Example 2 differs from Example 1 in that it does not contain polyepoxysuccinic acid and sodium polyaspartate from Group B, but retains only tetrasodium glutamate diacetate and trisodium methylglycine diacetate. The missing amounts are made up by demineralized water, and the rest is the same as in Example 1.

[0101] Comparative Example 3 differs from Example 1 in that the formulation does not contain the interface wetting and scale crack penetration components of Group D, i.e., it does not contain sodium dioctyl sulfosuccinate and decyl glucoside. The missing components are made up by demineralized water, and the rest is the same as in Example 1.

[0102] Comparative Example 4 differs from Example 1 in that the formulation does not contain polydimethyldiallylammonium chloride, and the missing amount is made up by demineralized water. Otherwise, it is the same as Example 1.

[0103] Comparative Example 5 is a conventional strong acid cleaning control. It uses hydrochloric acid aqueous solution with an acidity equivalent to that of the cleaning solution in Example 1 as the cleaning agent. It does not contain Group B, Group C, Group D and auxiliary functional components. The cleaning process steps are the same as those in Example 1.

[0104] In Experiment 1, a cleaned and dried calcium silicate composite scale sample was taken and cleaned using the cleaning agents obtained in Examples 1 to 4 and Comparative Examples 1 to 5 according to their respective cleaning processes. The descaling rate was determined by the gravimetric method specified in the quality standard for chemical cleaning of industrial equipment, i.e., the ratio of the mass difference of the scale sample before and after cleaning to the mass of the scale before cleaning. The calcium ions in the cleaning waste liquid were determined by the EDTA titration method for the determination of calcium and magnesium ions in industrial circulating cooling water. The soluble silicon was determined by the silicon molybdenum blue colorimetric method specified in the determination of silicon in industrial circulating cooling water and boiler water. The time for complete dissolution of calcium silicate was the time required for a quantitative amount of calcium silicate scale to completely dissolve in the specified cleaning solution.

[0105] Table 1. Comparison of descaling rate, calcium silicate leaching amount, and complete dissolution time of calcium silicate between each embodiment and each comparative example:

[0106]

[0107] Table 1 shows the descaling rate, calcium ion and soluble silica dissolution amount, and calcium silicate complete dissolution time of each embodiment and comparative example on the same scale sample. Table 1 indicates that the descaling rates of Examples 1 to 4 are all no less than 98.3% and the complete dissolution time is relatively short, significantly better than the comparative examples. Among them, Comparative Example 1, which does not contain the C-group silicon complex component, has the lowest soluble silica dissolution amount and the longest complete dissolution time, while Comparative Example 5, which uses a strong acid, has the lowest descaling rate. In this invention, the formulation of the pharmaceutical material simultaneously includes a group A of acid hydrolysis components, a group B of chelating and dispersing components, and a group C of silicon complexing components. Methylsulfonic acid, glycolic acid, and L-malic acid in group A dissociate the calcium silicate scale layer, releasing calcium ions and silicic acid. Tetrasodium glutamate diacetate and trisodium methylglycine diacetate in group B chelate and fix the released calcium ions. D-sorbitol, D-mannitol, and sodium gluconate in group C complex and stabilize the released silicic acid. Both the calcium and silicon components of the scale are simultaneously removed from the liquid phase. The dissolution equilibrium of calcium silicate proceeds towards dissociation due to the continuous removal of products at both ends, resulting in a high descaling rate and rapid dissolution. Comparative Example 1 lacks group C, so the silicic acid cannot be complexed and instead condenses and precipitates back, making the scale dissolution process partially reversible. Therefore, the amount of soluble silicon dissolved is low, and the dissolution is slow. Comparative Example 5 uses a strong acid, and after the silicon is dissociated, a large amount is converted into colloidal secondary deposition, resulting in the lowest descaling rate.

[0108] In Experiment 2, after cleaning with each of the above cleaning agents according to their respective cleaning processes, the turbidity, colloidal silica content, and amount of secondary deposits on the membrane surface were measured. The turbidity was determined according to the turbidity of water. The colloidal silica content was calculated as the difference between the total silica in the cleaning solution and the reactive soluble silica measured by the molybdenum blue colorimetric method. The amount of secondary deposits on the membrane surface was calculated as the mass of the residual deposits per unit membrane area after cleaning.

[0109] Table 2. Comparison of turbidity, colloidal silica content, and amount of secondary deposits on the membrane surface of the cleaning solutions in each example and each comparative example:

[0110]

[0111] Table 2 shows the turbidity, colloidal silica content, and amount of secondary deposits on the membrane surface after cleaning for each sample. Table 2 indicates that the three indicators in Examples 1 to 4 are all relatively low, while those in Comparative Example 1 (without the group C silica complex component) and Comparative Example 5 (using a strong acid) are significantly higher. In this invention, the group C silica complex component, in combination with groups A and B, allows multiple adjacent hydroxyl groups in D-sorbitol, D-mannitol, and sodium gluconate molecules to form silica-polyol complexes with silica monomers. This ensures that the dissociated silica exists stably in the liquid phase in a complexed form without condensing into colloidal silica, thereby inhibiting the secondary deposition of colloidal silica on the membrane surface. Comparative Example 1 lacks this component, causing silica to condense and deposit into colloidal silica, resulting in increased turbidity, colloidal silica content, and amount of secondary deposits on the membrane surface. The strong acid system in Comparative Example 5, lacking any silica complexing or dispersing components, shows the most significant formation of secondary colloidal silica.

[0112] In Experiment 3, polyamide reverse osmosis membranes and 316L stainless steel hanging plates were placed in cleaning solutions diluted 3 to 8 times and contacted at 25 to 35°C for 16 to 24 hours. The pure water flux retention rate and desalination rate of the membranes were determined according to the methods specified for spiral-wound polyamide composite reverse osmosis membrane elements. The membrane mass loss rate was calculated as the ratio of the difference in dry mass of the membrane before and after contact to the dry mass before contact. The corrosion rate of 316L stainless steel was determined by the rotating hanging plate method for determining the corrosion inhibition performance of water treatment agents.

[0113] Table 3. Membrane compatibility and corrosion data of reverse osmosis membranes and 316L stainless steel in each embodiment and comparative example:

[0114]

[0115] Table 3 shows the effects of each sample on the polyamide reverse osmosis membrane and 316L stainless steel, namely, membrane mass loss rate, pure water flux retention rate, desalination rate decrease, and metal corrosion rate. Table 3 shows that the membrane mass loss rate of Examples 1 to 4 and Comparative Example 1 (excluding Group C) is no greater than 0.5%, the pure water flux retention rate is no less than 90%, the desalination rate decrease is no more than 0.5 percentage points, and the 316L corrosion rate is no greater than 0.5 mm·a. -1The physical properties of the reagents used in this invention are consistent with the requirements of the present invention, while the aforementioned indicators of Comparative Example 5, which uses a strong acid, are significantly deteriorated. This invention replaces the inorganic strong acid with an organic acid and adds benzimidazole to the auxiliary functional components. Methylsulfonic acid, glycolic acid, and L-malic acid are less corrosive than inorganic strong acids. Benzimidazole adsorbs on the metal surface to form a protective film, reducing the acid's corrosion of the metal. Therefore, while removing calcium silicate composite scale, the membrane and stainless steel components are protected. The strong acid system of Comparative Example 5 lacks corrosion inhibitors, resulting in membrane damage, decreased flux and desalination rate, and a high corrosion rate. This also indicates that the compatibility between the membrane and the metal stems from the component design of this invention rather than the object being cleaned itself.

[0116] In Experiment 4, a reverse osmosis second-stage membrane element with decreased permeate flow and increased inter-stage pressure differential after one year of operation was selected. Offline cleaning was performed using the reagents and cleaning methods described in Example 1. Permeate flow, inter-stage pressure differential, and desalination rate before and after cleaning were measured under the same test conditions according to the methods specified in relevant standards. The permeate flux recovery rate was calculated as the ratio of permeate flow after cleaning to the rated permeate flow, and the pressure differential recovery rate was calculated as the ratio of the difference in pressure differential before and after cleaning to the difference in pressure differential before cleaning and the pressure differential of the new membrane.

[0117] Table 4 shows the performance and recovery rate of the reverse osmosis membrane element before and after cleaning using the method in Example 1:

[0118]

[0119] Table 4 shows the changes in permeate flow, inter-stage pressure difference, desalination rate, and single membrane element mass before and after cleaning, as well as the permeate flux recovery rate and pressure difference recovery rate, after using the reagents and cleaning method of Example 1. Table 4 also shows that the permeate flow rate increased from 116 m³ / s after cleaning. 3 ·h -1 Restored to 150m 3 ·h -1 The permeate flux recovery rate was 93.8%, the inter-stage pressure differential decreased from 0.26 MPa to 0.09 MPa (pressure differential recovery rate 89.5%), the desalination rate increased from 97.7% to 98.5%, and the mass of a single membrane element decreased from 15.4 kg to 13.3 kg. The permeate flux recovery rate was not less than 85%, and the pressure differential recovery rate was not less than 80%, consistent with the membrane performance recovery level required for determining the cleaning endpoint in step S41 of this invention. The reagent material of this invention softens, dissociates, and disperses the calcium silicate composite scale. After the scale layer is dissociated and dispersed away from the membrane surface, the flow resistance of water on the membrane surface and in the flow channels decreases, and the effective filtration area of ​​the membrane is restored. Therefore, the permeate flow and desalination rate increase, the inter-stage pressure differential decreases, and the membrane element mass decreases.

[0120] In Experiment 5, the cleaning agent and cleaning method of Example 1 were used. The cleaning was performed according to the intelligent sensor group in step S32 and the industrial controller in step S33 of this invention. pH, conductivity, turbidity, calcium ions, and soluble silica were measured according to relevant standards. The pressure difference before and after the membrane and the circulation flow rate were measured by the system pressure transmitter and flow meter. The normalized cleaning state index was calculated in real time by the industrial controller according to the formula described in this invention.

[0121] Table 5. Records of status data, normalized cleaning status index, and control actions at various moments during the cleaning process in Example 1:

[0122]

[0123] Table 5 shows the pH, calcium concentration, soluble silica concentration, turbidity, and pressure difference across the membrane at various times during the cleaning process in Example 1, as well as the normalized cleaning state index calculated in real time by the industrial controller and the corresponding control actions. Table 5 shows that as cleaning progresses, the calcium and soluble silica concentrations first increase rapidly and then stabilize, while the pressure difference across the membrane gradually decreases. The normalized cleaning state index is higher in the middle of the cleaning process and decreases in the later stages. When sampling continuously at intervals of 10 to 15 minutes near the endpoint, the relative increases in calcium ions and soluble silica between adjacent samples are no greater than 5%, the pH drift is no greater than 0.1, and the turbidity increase rate is no greater than 3%. Simultaneously, the pressure difference recovery rate reaches 89.5%. The industrial controller determines the endpoint has been reached after 3.5 hours when the normalized cleaning state index drops below the endpoint threshold of 0.15. In contrast, achieving a similar effect through manual, empirical cleaning of the same scale sample takes approximately 4.2 hours. In step S32, the present invention sets up a smart sensor group, and in step S33, the industrial controller performs threshold zoning control according to the normalized cleaning state index. The pressure difference, dissolution rate, turbidity, pH deviation and flow deviation with different dimensions are normalized to a quantity between 0 and 1 and then weighted and fused into a single index. Based on this, the industrial controller triggers the addition of reagents, enhanced circulation and endpoint switching in zones, so that the cleaning process is automatically carried out according to the real-time status, the endpoint is determined earlier than manual and over-cleaning is avoided.

[0124] In Experiment 6, the cleaning waste liquid obtained from the cleaning in Example 1 was subjected to volume reduction treatment according to step S43 of the present invention. After adjusting the pH of the waste liquid to 10.0, magnesium chloride, lime milk and polyferric sulfate were added. After settling for 40 minutes, the waste liquid was filtered through a filter with a pore size of 10 μm. The pH, calcium ion, soluble silica and turbidity of the waste liquid before and after treatment were determined according to the relevant standards. The chemical oxygen demand was determined according to the dichromate method for the determination of chemical oxygen demand in water.

[0125] Table 6 is a comparison table of water quality before and after the volume reduction treatment of cleaning wastewater in Example 1:

[0126]

[0127] Table 6 shows the pH, calcium ion concentration, soluble silica concentration, turbidity, and chemical oxygen demand of the cleaning wastewater from Example 1 before and after volume reduction treatment. Table 6 also shows that the calcium ion concentration decreased from 852 mg / L after treatment. -1 Reduced to 88 mg·L -1 Soluble silicon consists of 628 mg·L -1 Reduced to 24 mg·L -1 Chemical oxygen demand (COD) increased from 3150 mg·L⁻¹ -1 Reduced to 460 mg·L -1 The turbidity decreased from 42 NTU to 4.5 NTU, and the pollution load significantly decreased. In step S43 of this invention, the cleaning waste liquid is reduced in volume. After the waste liquid is adjusted to alkalinity, the added magnesium salt generates magnesium hydroxide and adsorbs and co-precipitates silicic acid. Calcium precipitates as calcium carbonate and hydroxide. Polyferric sulfate coagulant promotes the aggregation and sedimentation of fine particles. Silicon and calcium are thus separated into sludge, and the pollution load of the clear liquid decreases.

[0128] Experimental Example 7: The pharmaceutical materials obtained in Examples 1 to 4 were used to determine their physical properties and biodegradability. pH, viscosity, surface tension, and density were determined according to the relevant standards. Storage stability was determined by whether the product separated into layers or precipitated after being stored at -5 to 45°C for 30 days. Rapid biodegradability was determined by the closed-bottle method for rapid biodegradability of chemicals, and the biodegradation rate was calculated based on 28 days.

[0129] Table 7 shows the physical properties and biodegradability of the pharmaceutical materials in each embodiment:

[0130]

[0131] Table 7 shows the pH, viscosity, surface tension, density, storage stability, and 28-day biodegradation rate of the pharmaceutical materials in each example. From Table 7, it can be concluded that the pH of Examples 1 to 4 is 1.2 to 2.6, the viscosity is 18 to 68 mPa·s, and the surface tension is 28 to 34 mN·m. -1 Its density is 1.10 to 1.23 g·cm³. -3After 30 days of storage, no stratification or precipitation was observed, all within the physical property range of the pharmaceutical material of this invention. Its 28-day biodegradation rate was no less than 60%, classifying it as a rapidly biodegradable substance. In steps H1 to H5, this invention employs phase separation preparation, batch acidification, and the final addition of polydimethyldiallyl ammonium chloride. It also selects biodegradable components such as tetrasodium diacetate of glutamate, polyepoxysuccinic acid, sodium polyaspartate, and decyl glucoside. The polymer is first hydrated and dissolved, and the positively charged polydimethyldiallyl ammonium chloride is added last after the system has stabilized. This avoids association and flocculation between the positively charged polymer and surfactant, resulting in a clear, non-stratified, and stable pharmaceutical agent. The selected components themselves are biodegradable, resulting in a high biodegradation rate, consistent with the positioning of this pharmaceutical material as a biodegradable water pollution control agent.

[0132] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A calcium silicate composite scale cleaning agent, characterized in that, The total amount of components is 1000 parts by weight, with the demineralized water being the remainder to bring the total to 1000 parts. The proportions of polyepoxysuccinic acid, sodium polyaspartate, tetrasodium diacetate of glutamic acid, and polydimethyldiallyl ammonium chloride are based on the content of the active ingredients. The cleaning agent consists of groups A, B, C, D, and auxiliary functional components. Group A, acid hydrolysis components: 50-120 parts of methanesulfonic acid, 20-60 parts of glycolic acid, and 10-40 parts of L-malic acid; Group B, chelated and dispersed components: 10-40 parts of tetrasodium glutamate diacetate, 5-20 parts of trisodium methylglycine diacetate, 10-30 parts of polyepoxysuccinic acid, and 5-20 parts of sodium polyaspartate. Group C, silicon complex components: D-sorbitol 10-40 parts, sodium gluconate 5-20 parts, D-mannitol 5-20 parts; Group D, components for interface wetting and scale / fracture penetration: sodium dioctyl sulfosuccinate 2-10 parts, decyl glucoside 2-10 parts; Auxiliary functional components: 1-5 parts benzimidazole, 2-8 parts polydimethyldiallylammonium chloride, and 30-80 parts glycerol.

2. The calcium silicate composite scale cleaning agent according to claim 1, characterized in that, By mass fraction, Group A consists of 80 parts methanesulfonic acid, 40 parts glycolic acid, and 20 parts L-malic acid; Group B consists of 25 parts tetrasodium glutamate diacetate, 10 parts trisodium methylglycine diacetate, 20 parts polyepoxysuccinic acid, and 10 parts sodium polyaspartate; Group C consists of 25 parts D-sorbitol, 10 parts sodium gluconate, and 10 parts D-mannitol; Group D consists of 5 parts sodium dioctyl sulfosuccinate and 5 parts decyl glucoside; the auxiliary functional components are 3 parts benzimidazole, 4 parts polydiallyl ammonium chloride, and 50 parts glycerol, with the demineralized water to be made up to 1000 parts.

3. The calcium silicate composite scale cleaning agent according to claim 1, characterized in that, The mass ratio of the acid hydrolysis component in group A to the chelate dispersion component in group B is 1.8–2.5:

1. The mass ratio of the sum of tetrasodium glutamate diacetate and trisodium methylglycine diacetate in group B to the sum of polyepoxysuccinic acid and sodium polyaspartate is 1–2:

1. The mass ratio of the silicon complex component in group C to the chelate dispersion component in group B is 0.5–1.5:

1.

4. The calcium silicate composite scale cleaning agent according to claim 1, characterized in that, The cleaning agent is prepared by the following steps: H1. Take 60% to 70% of the total demineralized water, first add polyepoxysuccinic acid and sodium polyaspartate from group B and stir until hydrated and dissolved, then add tetrasodium glutamate diacetate and trisodium methylglycine diacetate and stir until dissolved to obtain the base solution of group B. H2. Add D-sorbitol, sodium gluconate and D-mannitol from group C to group B base solution and stir until dissolved to obtain intermediate solution containing silicon complex component; H3. Sodium dioctyl sulfosuccinate and decyl glucoside from group D are premixed with glycerol and benzimidazole from the auxiliary functional components to obtain a predispersed phase, which is then added to the intermediate liquid obtained in step H2 and stirred evenly. H4. Under temperature control and online turbidity monitoring, the methanesulfonic acid, glycolic acid and L-malic acid of group A are added to the liquid obtained in step H3 in batches. After each batch is added, the turbidity of the material is no greater than 10 NTU and the pH change is no greater than 0.05 within 10 minutes before adding the next batch to obtain an acidified mixture. H5. Add polydimethyldiallyl ammonium chloride, an auxiliary functional component, to the acidified mixture, add demineralized water, stir evenly, and filter through a 5μm pore size filter to obtain the cleaning agent.

5. The calcium silicate composite scale cleaning agent according to claim 4, characterized in that, In step H1, the stirring and dissolving temperature is 30–40°C. In step H4, the kettle temperature is controlled to be no higher than 35°C, and the acid hydrolysis component of group A is added in 3–5 batches. In step H5, after adding polydimethyldiallyl ammonium chloride, the material is monitored with an online pH meter, conductivity meter, and turbidity meter. When the pH change is no greater than 0.05, the conductivity change is no greater than 1%, and the turbidity change is no greater than 1 NTU within 10 minutes, the readings are considered stable. Deionized water is added to correct the total content of effective substances according to the density or refractive index calibration curve. Then, vacuum degassing is performed at -0.06 to -0.09 MPa for 5–20 minutes to obtain a uniform, clear, and non-stratified cleaning agent with a turbidity of no more than 10 NTU and no visible suspended matter.

6. A water treatment cleaning method for calcium silicate composite scale, characterized in that, Using the cleaning agent according to any one of claims 1 to 5, Includes the following steps: S1, Preparation of cleaning solution: The cleaning agent is added to water and diluted and mixed to obtain a cleaning solution; S2, Immersion and Permeation: Fill the reverse osmosis or nanofiltration water treatment system to be cleaned with cleaning solution and let it stand to soak, so as to obtain a softened scale layer after immersion. S3, Circulation and Dissociation: Drive the cleaning fluid to circulate in the water treatment system and collect cleaning status data. Based on the cleaning status data, add reagents, adjust the circulation intensity and switch the cleaning stage to dissociate, peel off and suspend the calcium silicate complex scale in the cleaning fluid, and obtain cleaning waste liquid containing calcium and soluble silicon. S4, Endpoint Determination and Drainage: After determining the cleaning endpoint based on the cleaning status data, the cleaning waste liquid is discharged and reduced in volume. S5, Rinse and Reset: Introduce reverse osmosis permeate or demineralized water into the system for replacement rinsing, so that the water treatment system is reset to the state of producing water or producing water operation.

7. The water treatment cleaning method according to claim 6, characterized in that, In step S1, the cleaning agent is diluted 3 to 8 times by mass or volume to prepare a cleaning solution with a pH of 1.5 to 3.0; in step S2, the soaking time is 30 to 120 minutes; in step S3, the temperature of the cleaning solution is 25 to 35°C, and the circulation pressure is not greater than 0.3 MPa; in a water treatment system with a reverse circulation pipeline, the cleaning solution is periodically switched between forward and reverse flow; in a water treatment system without a reverse circulation pipeline, segmented circulation, pulse circulation, or intermittent soaking is used.

8. The water treatment cleaning method according to claim 6, characterized in that, In step S3, the cleaning status data is collected by a smart sensor group. The smart sensor group includes a pH sensor, a temperature sensor, and a conductivity sensor located in the cleaning fluid loop; a turbidity sensor, a calcium ion detector, and a soluble silica detector located at the return port of the cleaning water tank; and a membrane differential pressure sensor, a circulation flow sensor, and a liquid level sensor located at the inlet and outlet of the water treatment system. The calcium ion detector and the soluble silica detector are bypass automatic sampling detectors equipped with filtration, dilution, temperature compensation, and two-point calibration modules. Calcium ions are determined by ion-selective electrode method or colorimetric method, and soluble silica is determined by silicomolybdenum blue colorimetric method. The sampling cycle is 5 to 15 minutes.

9. The water treatment cleaning method according to claim 8, characterized in that, The cleaning status data is sent to the industrial controller, which collects pH, temperature, pressure difference before and after the membrane, circulation flow rate, liquid level and turbidity data in a period of 5 to 60 seconds, and collects calcium ion concentration and soluble silicon concentration data in a period of 5 to 15 minutes, and performs temperature compensation and moving average filtering on the data. The industrial controller calculates the calcium-silicon leaching rate, differential pressure load, turbidity load, pH deviation, and flow rate deviation, and calculates the normalized cleaning state index according to the following formula. : ； In the formula, The normalized cleaning state index has a value of 0 to 1. , , , , These are weighted coefficients, and the sum of the five is 1. This is the normalized value of the pressure difference across the membrane relative to the initial pressure difference; The calcium-silicon dissolution rate is a normalized value relative to a preset dissolution rate threshold. The calcium-silicon dissolution rate is the increment of the sum of the calcium ion mass concentration and the soluble silicon mass concentration in two consecutive samples divided by the sampling interval. This is the normalized value of the cleaning fluid turbidity relative to a preset turbidity threshold. This is the normalized deviation of the real-time pH value of the cleaning solution from the set pH value. This is the normalized deviation of the circulating flow rate from the set circulating flow rate; , , , and All are quantities between 0 and 1; When the real-time pH value of the cleaning solution is 0.1 to 0.3 higher than the set pH value, and When the amount exceeds the preset replenishment threshold, the industrial controller activates the reagent replenishment pump for intermittent replenishment. After each replenishment, the reagent is circulated and mixed for 5-10 minutes, and the calculation is recalculated. ;when When the system pressure exceeds the preset enhanced circulation threshold and is no greater than 0.3 MPa, the industrial controller increases the cleaning pump frequency or switches between forward and reverse circulation valves; when When the pH value is below the preset endpoint threshold, the industrial controller switches to the drainage and rinsing stage. When the pH value of the cleaning solution is below 1.5, the temperature is above 35°C, the system pressure is above 0.3MPa, the liquid level is below the safe liquid level, or the sensor signal is abnormal, the industrial controller reduces the cleaning pump frequency, stops the chemical replenishment pump, and executes a shutdown alarm.

10. The water treatment cleaning method according to claim 6, characterized in that, In step S4, when the relative increase in calcium ions and the relative increase in soluble silica in the cleaning waste liquid are both no greater than 5% in two consecutive samplings with an interval of 10-15 minutes, the pH drift of the cleaning liquid is no greater than 0.1, the turbidity growth rate is no greater than 3%, and the recovery rate of the pressure difference across the membrane of the water treatment system is no less than 80% or the recovery rate of the permeate flux is no less than 85%, the cleaning endpoint is determined to have been reached. The volume reduction treatment involves adjusting the discharged cleaning waste liquid to pH 9.5-11.0, adding magnesium salt and lime slurry at a magnesium ion to soluble silica molar ratio of 1-3:1, and adding iron salt or aluminum salt coagulant. After settling for 20-60 minutes, the liquid is filtered through a filter with a pore size of no more than 10 μm to reduce the concentration of soluble silica and calcium ions in the clear liquid to the influent limit of the subsequent discharge or reuse treatment unit.

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