Composite flocculating precipitant and method for its preparation
By freezing the initial coordination aggregates in a non-equilibrium state to form metastable precursors, the problem of insufficient structural potential of water pollution control agents in existing technologies is solved, and the composite flocculant and precipitant achieves rapid response and continuous sedimentation effect in water bodies.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING QIWO ECOLOGICAL TECH CO LTD
- Filing Date
- 2026-04-30
- Publication Date
- 2026-06-05
Smart Images
Figure CN122144868A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of water treatment agents, and in particular to a composite flocculant and precipitant and its preparation method. Background Technology
[0002] With the increasing demand for the treatment of industrial wastewater, municipal sewage, and complex water bodies containing suspended solids, water pollution control agents and materials have gradually evolved from single inorganic salt flocculants or single organic polymer flocculants to composite systems emphasizing structural regulation, interfacial interactions, and multi-stage action mechanisms. Related technologies typically revolve around aluminum salts, iron salts, and their composite precursor systems, and improve the flocculation behavior, sedimentation behavior, and applicable water quality range of agents after addition through methods such as complexation regulation, confined construction, component compounding, and two-component storage. This has led to a development trend in water pollution control agents and materials that is evolving from static formulation design to dynamic structural construction.
[0003] While existing technologies can achieve certain treatment effects through conventional pre-hydrolysis, complexation stabilization, or component compounding, most of their technical routes aim to form thermodynamically stable final products. This results in the precursor system having basically completed its structural shaping during the preparation stage, and its structural potential for further thawing and release and directional rearrangement after entering the water body is insufficient. It is difficult to take into account both the rapid action in the early stage and the subsequent sedimentation structure evolution requirements. Summary of the Invention
[0004] In view of this, this application provides a composite flocculant and a method for preparing the same.
[0005] According to one aspect of this disclosure, a method for preparing a composite flocculant is provided, comprising: step 1: providing a metal salt precursor, a restricted construction component, and a non-polymeric organic structure regulating component; Step 2: The metal salt precursor is pre-assembled with the confined building components to form an initial coordination aggregate that is in the process of continuous evolution; Step 3: Before the initial coordination aggregates reach the thermodynamically stable final state, a non-equilibrium freezing process is performed on the initial coordination aggregates to obtain a metastable precursor; the non-equilibrium freezing process is used to interrupt the continuous evolution process of the initial coordination aggregates. Step 4: Separate and construct the metastable precursor and the non-molecular organic structure regulating component to obtain the composite flocculant; or combine the metastable precursor and the non-molecular organic structure regulating component under freeze-holding conditions to obtain the composite flocculant. The non-equilibrium freezing treatment is any one or a combination of at least two of the following: rapid temperature freezing, instantaneous phase change freezing, solvent switching freezing, sudden change in ion environment freezing, local dehydration freezing, or rapid pH transition freezing. The metastable precursor is capable of thawing and structural rearrangement under aqueous conditions.
[0006] According to one aspect of this disclosure, a composite flocculant is provided, comprising: a metastable precursor and a non-molecular organic structure regulating component; The metastable precursor is formed by pre-assembling a metal salt precursor and a restricted building component and then subjecting it to non-equilibrium freezing treatment. The metastable precursor is not a thermodynamically stable final-state product, but a frozen-state precursor structure locked in a non-final-state chemical state. The non-polymer organic structure regulating component is disposed separately from the metastable precursor, or is disposed in combination with the metastable precursor under freeze-holding conditions; The metastable precursor can undergo thawing and structural rearrangement under aqueous conditions.
[0007] The beneficial effects of this invention are as follows: by implementing non-equilibrium freezing treatment on the initial coordination aggregates to form metastable precursors, the key step of structural locking can be achieved before the system evolves to the thermodynamically stable final state. This preserves the unfinal state coordination relationships, local confined configurations, and subsequently releasable frozen state structural information. Furthermore, the resulting water pollution control agents and materials trigger thawing and structural rearrangement after entering the water body, allowing the active precursor structures with continuous evolution capabilities to participate in pollutant capture, interface reconstruction, and sedimentation structure establishment. This, in turn, helps to improve the structural responsiveness, continuity of action, process controllability, and application adaptability of the agents during their action. Attached Figure Description
[0008] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0009] Figure 1 The particle size distribution curves of DLS in different construction states are shown.
[0010] Figure 2 The FTIR spectra of samples in different states are shown. Detailed Implementation
[0011] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.
[0012] This application also provides a method for preparing a composite flocculant, which includes: Step 1: providing a metal salt precursor, a restricted construction component, and a non-polymeric organic structure regulating component.
[0013] Step 2: The metal salt precursor is pre-assembled with the restricted building components to form an initial coordination aggregate in a continuous evolution process.
[0014] It should be noted that the initial coordination aggregate refers to the metal-confined building component aggregate state formed after the metal salt precursor and the confined building component come into contact during the pre-assembly stage, and has not yet continued to age to the thermodynamically stable final state. It is different from the original metal precursor liquid that has not undergone substantial interaction, and also different from the stable final state precipitate or final state aggregate product formed after continuous aging.
[0015] Step 3: Before the initial coordination aggregates reach the thermodynamically stable final state, the initial coordination aggregates are subjected to non-equilibrium freezing treatment to obtain metastable precursors; the non-equilibrium freezing treatment is used to interrupt the continuous evolution process of the initial coordination aggregates.
[0016] It should be noted that the non-equilibrium freezing refers to interrupting the process of the initial coordination aggregate continuing to coordinate, continue to aggregate, continue to hydrolyze, or continue to rearrange at a preset time point through at least one of the following mutation methods: rapid pH jump, solvent switching, sudden change of ion environment, local dehydration, or temperature mutation, and retaining the non-final state under subsequent holding conditions, rather than allowing it to continue to evolve into a thermodynamically stable final state. The metastable precursor is obtained by first forming an initial coordination aggregate from a metal salt precursor and a restricted building component, and then undergoing non-equilibrium freezing treatment. The formation order is "pre-assembly first, freezing lock-in later", which is different from the system obtained by directly treating the original precursor liquid and ordinary aging intermediate products. The metastable precursor is not the original precursor liquid, not a common aging product, nor a thermodynamically stable final precipitate. The boundary between it and the initial coordination aggregate and the final product can be defined by at least one difference in species distribution, particle size, zeta potential, spectroscopic signal, morphological characteristics, or local confined structure. like Figure 1As shown, after pre-assembly of the metal salt precursor and the confined building blocks, the system forms initial coordination aggregates. Following non-equilibrium freezing before reaching a thermodynamically stable final state, the particle size distribution of the resulting metastable precursor component A undergoes further migration compared to the initial coordination aggregates, maintaining a identifiable difference from the final aging products. This indicates that this application does not obtain ordinary aging intermediates or final-state precipitates, but rather locks the system in a non-final chemical state. This result demonstrates that the metastable precursor lies within an identifiable boundary region between the initial aggregates and the final aging products, thus providing a basis for subsequent thawing and structural rearrangement after immersion in water.
[0017] The metastable precursor has identifiable state characteristics, which include at least one of the following: retaining unfinished coordination relationships, retaining local confinement information formed by non-equilibrium processing, and not spontaneously transforming into the final product immediately during the retention phase. The metastable precursor is preferably identified by satisfying at least one of the following main criteria and in combination with at least one auxiliary criterion: Main criteria: When measured by DLS at 25°C and under the same dilution conditions, the Z-average particle size of the metastable precursor is 120–450 nm, preferably 150–350 nm; its main peak position shifts by at least 20 nm, preferably at least 50 nm, compared to the initial coordinated aggregate, and maintains a particle size difference of at least 15%, preferably at least 20%, compared to the final aged product.
[0018] Auxiliary criterion 1: The zeta potential of the metastable precursor is +5mV to +30mV, preferably +8mV to +22mV, and the difference between it and the final-state aging product is not less than 5mV.
[0019] Auxiliary criterion 2: The metastable precursor exhibits identifiable differences from the final-state aging product in the characteristic absorption range of 1600–1400 cm⁻¹ in the FTIR spectrum. Preferably, ν_as(COO⁻) is located in the range of 1580–1615 cm⁻¹, and ν_s(COO⁻) is located in the range of 1380–1415 cm⁻¹. Furthermore, the difference between the peak position or peak intensity ratio in this range and that of the final-state aging product is not less than 10%.
[0020] Auxiliary criterion 3: After being kept at 0–10°C for 12–72 h, the metastable precursor still meets the above DLS main criterion and maintains a identifiable difference from the final-state aging product.
[0021] The non-equilibrium freezing process should have repeatable conditions, including at least one set of operational boundaries among the raw material type, addition sequence, pre-assembly time, freezing triggering method, and freezing maintenance conditions.
[0022] Step 4: Separate and construct the metastable precursor and the non-molecular organic structure regulating component to obtain a composite flocculant, or combine the metastable precursor and the non-molecular organic structure regulating component under freeze-holding conditions to obtain a composite flocculant.
[0023] It should be noted that the separation construction refers to constructing the metastable precursor as component A and the non-polymeric organic structure regulating component as component B, and storing them separately to prevent the metastable precursor from continuing to coordinate, aggregate or rearrange in advance during the storage stage, thereby maintaining its non-final state until the use stage. The metastable precursor and the non-polymer organic structure regulating component are constructed separately, rather than using ordinary packaging. This is to maintain the metastable precursor in a frozen state before use, and to allow it to participate in the subsequent thawing and structural rearrangement process together with the non-polymer organic structure regulating component when it enters the target water body.
[0024] The non-equilibrium freezing process is any one or a combination of at least two of the following: rapid temperature freezing, instantaneous phase change freezing, solvent switching freezing, sudden change in ionic environment freezing, local dehydration freezing, or rapid pH transition freezing.
[0025] The metastable precursor is capable of thawing and structural rearrangement under aqueous conditions.
[0026] It should be noted that the "thawing and structural rearrangement" refers to the process by which metastable precursors, after entering the target water body, continue to undergo coordination, aggregation, hydrolysis, or internal structural rearrangement under the influence of dilution, pH changes, ionic strength changes, or changes in mixing conditions, thereby forming a flocculation and sedimentation process that is different from the final state direct addition system.
[0027] like Figure 2 As shown, the metastable precursor A component differs from the final-state aging product in the characteristic absorption range, indicating that the metastable precursor retains a coordination environment and local structural information different from the final-state product. At the same time, the spectra of the flocs formed after A / B components enter the water are different from those of the metastable precursor and the final-state aging product, indicating that the metastable precursor can undergo thawing and structural rearrangement under the target water conditions, and can synergistically participate in the subsequent structural construction with non-polymeric organic structure regulating components. This result supports the continuous technical route of "pre-assembly - non-equilibrium freezing lock-up - synergistic rearrangement after water entry" in this application from a spectroscopic perspective.
[0028] In some embodiments of this application, the contact pre-assembly is performed in the following order: First, the metal salt precursor is dispersed in the first liquid phase medium to form a metal precursor liquid.
[0029] The restricted building blocks are then introduced into the metal precursor solution for the first stage of contact.
[0030] Maintaining a preset contact time allows the metal salt precursor and the confined building component to form an unterminated initial coordination aggregate.
[0031] After the first stage of contact is completed, no final aging treatment is performed, and the process proceeds directly to step 3.
[0032] It should be noted that the direct entry into step 3 after the first stage of contact is to implement non-equilibrium freezing treatment while the initial coordination aggregate is still in the stage of continuous evolution but has not yet reached the final state, thereby achieving the locking of the non-final state structure, rather than allowing the system to continue aging to the stable final state.
[0033] In some embodiments of this application, the non-equilibrium freezing process includes any of the following operation paths: Path A: Perform a rapid pH transition on the initial coordination aggregates and maintain a freeze-hold phase after the transition.
[0034] Path B: Introduce a second liquid phase medium different from the original liquid phase medium to the initial coordination aggregates, perform solvent switching, and form a freeze-holding stage during the switching process.
[0035] Path C: Introduce competing ions or ion environment regulating components into the initial coordination aggregate to induce a sudden change in the ion environment, and maintain a frozen state after the sudden change.
[0036] Path D: Local dehydration of the initial coordination aggregates, followed by a freeze-holding phase after dehydration.
[0037] In some embodiments of this application, the non-equilibrium freezing process does not transform the initial coordination aggregate into a thermodynamically stable final state, but rather maintains the metastable precursor in a non-final chemical state by interrupting at least one of its continued coordination, continued aggregation, continued hydrolysis, or continued rearrangement.
[0038] In some embodiments of this application, the metastable precursor and the non-polymeric organic structure regulating component are constructed using a two-component separation method, specifically including: Metastable precursors were constructed as component A, and non-polymeric organic structure regulating components were constructed as component B.
[0039] Component A and Component B are stored separately, and Component A and Component B do not come into substantial contact before use.
[0040] In some embodiments of this application, the non-polymeric organic structure regulating component is pretreated before being introduced into step 4. The pretreatment includes any one or a combination of at least two of the following: functional group partial neutralization treatment, ion form conversion treatment, liquid phase medium replacement treatment, or local concentration treatment.
[0041] The pretreated non-polymeric organic structure-regulating components are then separated or combined with the metastable precursor to construct the structure.
[0042] In some embodiments of this application, the metal salt precursor is selected from one or at least two of aluminum salt precursors, iron salt precursors, or aluminum-iron composite salt precursors.
[0043] The restricted building block is selected from one or at least two of the following: complexed restricted building blocks, shielded restricted building blocks, or confined restricted building blocks.
[0044] The non-polymeric organic structure regulating component is selected from one or at least two of small molecule organic compounds or oligomeric organic compounds.
[0045] This invention aims to construct a composite flocculant and precipitant. In embodiments of this application, it includes a metastable precursor and a non-polymeric organic structure-regulating component.
[0046] The metastable precursor is formed by pre-assembling a metal salt precursor and a restricted building block and then subjecting it to non-equilibrium freezing treatment.
[0047] It should be noted that the metastable precursor is a frozen precursor structure formed by the continuous action of "pre-assembly to form initial coordination aggregates" and "non-equilibrium freezing treatment to lock in", rather than a general precursor system obtained by directly treating the original precursor liquid.
[0048] The metastable precursor is not a thermodynamically stable final-state product, but a frozen-state precursor structure locked in a non-final chemical state.
[0049] It should be noted that there should be identifiable boundaries between the metastable precursor and the initial coordination aggregate, the ordinary aging product and the thermodynamically stable final state product. These boundaries can be characterized by differences in at least one of the following: species distribution, particle size, zeta potential, coordination state, spectroscopic signal, morphological features or local confinement information.
[0050] The non-polymeric organic structure regulating component is disposed separately from the metastable precursor, or disposed in combination with the metastable precursor under freeze-holding conditions.
[0051] The metastable precursor can undergo thawing and structural rearrangement under aqueous conditions.
[0052] It should be noted that the thawing and structural rearrangement of the metastable precursor under aquatic conditions are important processes for the present invention to achieve flocculation and sedimentation structure construction, so that the metastable precursor is not only an intermediate state, but also a key source of subsequent technical effects.
[0053] In some embodiments of this application, the composite flocculant is a two-component product, comprising component A and component B.
[0054] Component A includes a metastable precursor and a first medium.
[0055] Component B includes the non-polymeric organic structure regulating component and the second medium.
[0056] Component A and component B are packaged independently of each other.
[0057] In some embodiments of this application, the metastable precursor has at least one of the following state characteristics: retaining the unfinished coordination relationship of the initial coordination aggregate; retaining the locally confined structure formed by non-equilibrium freezing treatment; retaining the frozen state structure information formed by solvent switching, ion abrupt change, local dehydration or rapid pH transition.
[0058] It should be noted that the state characteristics should correspond to at least one set of verifiable identification criteria, which include at least one of species distribution differences, particle size differences, zeta potential differences, coordination or spectroscopic feature differences, morphological differences, and frozen state structural information that can still be retained after storage, so that the state constraints of metastable precursors are identifiable and verifiable.
[0059] The non-polymeric organic structure regulating component exists in an independent state separate from the metastable precursor phase.
[0060] like Figure 2 As shown, the metastable precursor A component differs from the final-state aging product in its characteristic absorption range, indicating that the metastable precursor retains a coordination environment and local structural information different from the final-state product. Furthermore, the spectra of the flocs formed after the A / B components enter the water are different from those of both the metastable precursor and the final-state aging product, suggesting that the metastable precursor can undergo thawing and structural rearrangement under the target water conditions, and synergistically participate in subsequent structural construction with non-polymeric organic structure-regulating components. These results, from a spectroscopic perspective, support the continuous technical route of this application: "pre-assembly—non-equilibrium freezing lock-up—synergistic rearrangement after water entry."
[0061] Example 1: Aluminum chloride hexahydrate was used as a metal salt precursor, trisodium citrate as a complex-type restricted building block, and sodium gluconate as a non-polymeric organic structure regulating component. First, aluminum chloride hexahydrate was dissolved in deionized water to form a metal precursor solution. Then, trisodium citrate was introduced for pre-assembly, causing the system to form unterminated initial coordination aggregates. Subsequently, the system was rapidly adjusted from acidic conditions to a higher pH using a rapid pH transition freezing method and maintained at low temperature to obtain metastable precursor component A. Sodium gluconate was then separately prepared as component B, and both were added to the simulated raw water in a predetermined ratio before use. The results showed that this example exhibited excellent performance in turbidity reduction, floc growth, settling velocity, and sludge compressibility.
[0062] Example 2: Maintaining the same raw material system as Example 1, i.e., still using the combination of aluminum chloride hexahydrate + trisodium citrate + sodium gluconate, but changing the non-equilibrium freezing path to solvent switching freezing in the preparation method; that is, after completing the pre-assembly and forming the initial coordination aggregates, instead of using pH transition, a second liquid phase medium different from the original liquid phase medium is introduced, so that the system enters the freezing and holding stage under the sudden change of solvent environment, forming the metastable precursor component A, which is then used in combination with the separately constructed component B; the results show that this example can also obtain lower residual turbidity and faster sedimentation rate, indicating that the technical effect of the present invention does not depend on a single freezing method, but comes from the process concept of "unterminated state lock-in" itself.
[0063] Example 3: The metal salt precursor was switched to ferric chloride hexahydrate. The restricted component was still trisodium citrate, and the non-polymeric organic structure regulating component was still sodium gluconate. In the specific preparation, the iron salt precursor solution was first prepared, and then trisodium citrate was introduced for pre-assembly. Subsequently, a rapid pH transition freezing method was used to lock it into a metastable precursor before the iron salt system continued to age to its final state. After forming a two-component system with sodium gluconate, it was used for water treatment evaluation. The results showed that even if the metal salt system was switched from aluminum salt to iron salt, the present invention could still obtain good turbidity reduction effect, large floc particle size and good sedimentation performance, indicating that the technical route is not limited to a single aluminum salt system.
[0064] Example 4: The metal salt precursor was kept as aluminum chloride hexahydrate, but the restricted construction component was switched to β-cyclodextrin to reflect the confined construction approach. Sodium gluconate was still used as the non-polymeric organic structure regulating component. During preparation, an aluminum salt precursor solution was first formed, and then β-cyclodextrin was introduced for pre-assembly to form the initial coordination aggregates under the restricted construction conditions. Subsequently, a rapid pH transition freezing method was used to form the metastable precursor component A, which was used together with component B to simulate raw water treatment. The results showed that this example could still achieve a high turbidity removal rate and a good sedimentation structure, indicating that the "restricted construction component" is not only achieved by complexing components, but can also achieve the technical objectives of this invention through different types of construction components.
[0065] Example 5: Component A was kept largely in the same system as in Example 1, using aluminum chloride hexahydrate + trisodium citrate and a rapid pH-jump freezing method to prepare the metastable precursor. However, the non-high molecular weight organic structure regulating component in component B was changed from sodium gluconate to sodium tartrate. That is, component A was first formed and maintained according to the method in Example 1, and then sodium tartrate was separately formulated as component B, which was added together with component A during the usage phase. The results showed that this example also achieved good flocculation and sedimentation effects, indicating that different types of small molecular weight organic structure regulating components can synergize with the metastable precursor, and are not arbitrarily added.
[0066] Example 6: Without significantly altering the raw material system, the combination of aluminum chloride hexahydrate + trisodium citrate + sodium gluconate was still used. However, the process window was optimized by shortening the pre-assembly time, extending the freeze-holding time, and optimizing the ratio of component A to component B. The preparation process still followed the main route of "pre-assembly → rapid pH transition freezing → A / B separation and construction," but the window was modified in the non-final state lock-up stage and usage conditions to examine the reproducibility of the invention within a certain parameter range. The results showed that this example achieved the best or near-best overall performance among all examples, indicating that the invention is not only effective under a single narrow condition, but can be further optimized within a reasonable process window.
[0067] Comparative Example 1: The same raw material system as Example 1 was used, namely aluminum chloride hexahydrate + trisodium citrate + sodium gluconate, but non-equilibrium freezing treatment was not performed in the preparation method. Specifically, after the initial coordination aggregates were pre-assembled, rapid pH transition freezing and other freezing treatments were not performed. Instead, the product was directly constructed and used for water treatment evaluation. The results showed that although this comparative example had a certain flocculation effect, its residual turbidity, settling velocity and floc particle size were significantly inferior to those of the present invention. This indicates that "non-equilibrium freezing" is not an optional additional step, but one of the necessary conditions for obtaining excellent results.
[0068] Comparative Example 2: Using the same raw material system as Example 1, but instead of immediately freezing in a non-equilibrium state after pre-assembly, the system was allowed to continue aging to a stable final state. That is, by extending the aging time and increasing the aging intensity, the system was allowed to evolve towards a thermodynamically stable final state. Then, it was combined with component B for water treatment. The results showed that the turbidity reduction performance, settling velocity, and sludge compressibility of this comparative example were all poor. This indicates that locking the system in a non-final state is better than allowing it to develop into a final product. It also proves that the "metastable precursor" as an intermediate state in this invention has practical significance.
[0069] Comparative Example 3: A one-step direct blending method was used to directly mix aluminum chloride hexahydrate, trisodium citrate, and sodium gluconate. That is, the initial coordination aggregates were not formed first, non-equilibrium freezing was not performed, and the A / B dual components were not distinguished. Instead, the components were mixed at one time and used directly as flocculants. The results showed that the overall performance of this comparative example was the worst or close to the worst among all samples. It was characterized by high residual turbidity, the lowest settling velocity, the smallest floc particle size, and the largest sludge volume. This shows that the sequential construction of the present invention is not a formal difference, but an important source of technical effect.
[0070] Comparative Example 4: Component A was prepared using the same method as in Example 1, namely, a metastable precursor was formed by pre-assembly and rapid pH transition freezing of aluminum chloride hexahydrate and trisodium citrate. However, component B was not added during use; only component A was added to the simulated raw water for evaluation. The results showed that although using component A alone was still superior to some traditional methods, the overall effect was significantly weaker than the complete example, especially in terms of settling velocity, floc structure, and sludge compression performance. This indicates that component B is not a decorative element but rather has a synergistic effect with the metastable precursor.
[0071] Table 1. Comparison of flocculation and sedimentation effects between the examples and comparative examples.
[0072] As shown in Table 1, each embodiment outperforms the comparative examples in terms of residual turbidity, settling velocity, floc particle size, and sludge volume. This indicates that the technical effect of the present invention does not stem from simple replacement of raw materials or adjustment of conventional formulations, but rather from a continuous technical route of "pre-assembly to form initial coordination aggregates—non-equilibrium freezing and locking into metastable precursors—separation and construction with non-polymer organic structure regulating components and synergistic rearrangement during the use stage." In particular, compared with comparative methods such as non-equilibrium freezing, aging to the final state, one-step direct blending, and single-component use, the present invention can simultaneously improve floc formation efficiency and settling structure construction capability, thereby demonstrating the substantial characteristics and progress brought about by the synergistic design of the evolution path of the precursor system and the structural rearrangement behavior during the use stage.
[0073] The above description is only a specific embodiment of this disclosure, but the protection scope of this disclosure is not limited thereto. The protection scope of this disclosure should be determined by the protection scope of the claims.
Claims
1. A method for preparing a composite flocculant and precipitant, characterized in that, Includes the following steps: Step 1: Provide metal salt precursors, restricted building blocks, and non-polymeric organic structure-regulating components; Step 2: The metal salt precursor is pre-assembled with the confined building components to form an initial coordination aggregate that is in the process of continuous evolution; Step 3: Before the initial coordination aggregates reach the thermodynamically stable final state, a non-equilibrium freezing process is performed on the initial coordination aggregates to obtain a metastable precursor; the non-equilibrium freezing process is used to interrupt the continuous evolution process of the initial coordination aggregates. Step 4: Separate and construct the metastable precursor and the non-molecular organic structure regulating component to obtain the composite flocculant; or combine the metastable precursor and the non-molecular organic structure regulating component under freeze-holding conditions to obtain the composite flocculant. The non-equilibrium freezing treatment is any one or a combination of at least two of the following: rapid temperature freezing, instantaneous phase change freezing, solvent switching freezing, sudden change in ion environment freezing, local dehydration freezing, or rapid pH transition freezing. The metastable precursor is capable of thawing and structural rearrangement under aqueous conditions.
2. The preparation method of the composite flocculant and precipitant as described in claim 1, characterized in that, The contact pre-assembly is performed in the following order: First, the metal salt precursor is dispersed in the first liquid phase medium to form a metal precursor liquid; The restricted building blocks are then introduced into the metal precursor solution for the first stage of contact. Maintain a preset contact time to allow the metal salt precursor and the confined building component to form an unterminated initial coordination aggregate; After the first stage of contact is completed, no final aging treatment is performed, and the process proceeds directly to step 3.
3. The preparation method of the composite flocculant and precipitant as described in claim 1, characterized in that, The non-equilibrium freezing process includes any of the following operation paths: Path A: Perform a rapid pH transition on the initial coordination aggregates and maintain a freeze-hold phase after the transition; Path B: Introduce a second liquid phase medium different from the original liquid phase medium to the initial coordination aggregates, switch the solvent, and form a freeze-holding stage during the switching process; Path C: Introduce competing ions or ion environment regulating components into the initial coordination aggregate to induce a sudden change in the ion environment, and maintain a frozen state after the sudden change; Path D: Local dehydration of the initial coordination aggregates, followed by a freeze-holding phase after dehydration.
4. The preparation method of the composite flocculant and precipitant as described in claim 3, characterized in that: Non-equilibrium freezing does not transform the initial coordination aggregate into a thermodynamically stable final state, but rather maintains the metastable precursor in a non-final chemical state by interrupting at least one of its continued coordination, continued aggregation, continued hydrolysis, or continued rearrangement.
5. The preparation method of the composite flocculant and precipitant as described in claim 1, characterized in that, The metastable precursor and the non-polymeric organic structure regulating component are constructed using a two-component separation method, specifically including: Metastable precursors were constructed as component A, and non-polymeric organic structure regulating components were constructed as component B. Component A and Component B are stored separately, and Component A and Component B do not come into substantial contact before use.
6. The preparation method of the composite flocculant and precipitant as described in claim 1, characterized in that, Before being introduced into step 4, the non-polymer organic structure regulating components are pretreated. The pretreatment includes any one or a combination of at least two of the following: functional group partial neutralization treatment, ion form conversion treatment, liquid phase medium replacement treatment, or local concentration treatment. The pretreated non-polymeric organic structure-regulating components are then separated or combined with the metastable precursor to construct the structure.
7. The method for preparing the composite flocculant as described in claim 1, 2, or 5, characterized in that: The metal salt precursor is selected from one or at least two of aluminum salt precursors, iron salt precursors, or aluminum-iron composite salt precursors. The restricted building component is selected from one or more of complexed restricted building components, shielded restricted building components, or confined restricted building components; The non-polymeric organic structure regulating component is selected from one or at least two of small molecule organic compounds or oligomeric organic compounds.
8. The composite flocculant and precipitant according to any one of claims 1 to 7, characterized in that, Including metastable precursors and non-polymeric organic structure-regulating components; The metastable precursor is formed by pre-assembling a metal salt precursor and a restricted building component and then subjecting it to non-equilibrium freezing treatment. The metastable precursor is not a thermodynamically stable final-state product, but a frozen-state precursor structure locked in a non-final-state chemical state. The non-polymer organic structure regulating component is disposed separately from the metastable precursor, or is disposed in combination with the metastable precursor under freeze-holding conditions; The metastable precursor can undergo thawing and structural rearrangement under aqueous conditions.
9. The composite flocculant and precipitant as described in claim 8, characterized in that: The composite flocculant is a two-component product, comprising component A and component B. Component A includes a metastable precursor and a first medium; Component B includes the non-polymeric organic structure regulating component and the second medium; Component A and component B are packaged independently of each other.
10. The composite flocculant and precipitant as described in claim 9, characterized in that, The metastable precursor has at least one of the following state characteristics: retaining the unfinished coordination relationship of the initial coordination aggregate; retaining the locally confined structure formed by non-equilibrium freezing treatment; retaining the frozen state structure information formed by solvent switching, abrupt ion change, local dehydration or rapid pH transition; The non-polymeric organic structure regulating component exists in an independent state separate from the metastable precursor phase.