CN114751483A

CN114751483A - Endogenous phosphorus passivation material for eutrophic water body and preparation method thereof

Info

Publication number: CN114751483A
Application number: CN202210548306.5A
Authority: CN
Inventors: 刘雪慧; 孙振华
Original assignee: Shandong Yuqing Environmental Technology Co ltd
Current assignee: Shandong Yuqing Environmental Technology Co ltd
Priority date: 2022-05-20
Filing date: 2022-05-20
Publication date: 2022-07-15

Abstract

An endogenous phosphorus passivation material for eutrophic water and a preparation method thereof belong to the technical field of phosphorus passivation materials. In the prior passivation technology, besides the common problem of low phosphorus adsorption capacity, the problems of short service life, single effect and the like exist, new passivation materials need to be applied for multiple times, and the prior passivation technology has no effective control effect on other ammonia nitrogen and the like in a water body. The invention comprises the following raw materials in parts by weight: 10-20 parts of zeolite powder, 30-50 parts of kaolin, 10-15 parts of lanthanum strong acid salt, 5-10 parts of magnesium strong acid salt and 5-10 parts of alum. The biological organic fertilizer is ecological and safe, has good compatibility with bottom mud, does not need to consume the alkalinity of water body when being applied, has passivation function to various anions or cations, and has large adsorption capacity and long effective life.

Description

Endogenous phosphorus passivation material for eutrophic water body and preparation method thereof

Technical Field

An endogenous phosphorus passivation material for eutrophic water and a preparation method thereof belong to the technical field of phosphorus passivation materials.

Background

Water eutrophication is an organic pollution type, and water quality is deteriorated due to excessive nutrients such as nitrogen and phosphorus entering natural water. The fertilizer applied to farmland generally has about half of the nitrogen fertilizer which is not utilized and flows into underground water or ponds and lakes, and a large amount of domestic sewage often leads the water body to be over-fertilized. The excessive nutrient substances promote the mass propagation of phytoplankton, such as blue algae, diatom and waterweeds in the water area, sometimes the whole water surface is covered by algae to form 'water bloom', the algae is deposited at the water bottom after death, and a large amount of dissolved oxygen is consumed by microbial decomposition, so that fishes die in batches due to oxygen deficiency.

In China, a large number of water bodies such as lakes, reservoirs, riverways and the like have serious eutrophication conditions, which causes the flooding of harmful algae, the disappearance of submerged vegetation and the serious damage to water quality and water ecology. Phosphorus is a limiting factor for algae growth, so that the reduction of phosphorus concentration is the key to the treatment of eutrophication and the restoration of the structure and function of the ecosystem.

In order to reduce the phosphorus concentration, on the one hand the input of exogenous phosphorus is controlled and, on the other hand, endogenous phosphorus is controlled, which, unlike exogenous phosphorus, can circulate constantly between the substrate sludge, the lake water and the algae. From the current technical application, sediment dredging, sediment coverage (physical isolation) and sediment phosphorus passivation are the main techniques for controlling endogenous phosphorus.

The sediment dredging method has the advantages of large sediment dredging engineering quantity, high construction cost and very troublesome sediment disposal after dredging.

The physical isolation of the sludge prevents the release of sludge phosphorus to some extent, but its disadvantages are also apparent. Firstly, the lake bed environment can be completely changed, and the living environment of benthos is damaged; secondly, to achieve the mud/water isolation effect, the covering layer must be thick (the thickness is generally more than 5 cm), so the engineering quantity and the cost are also large; thirdly, the covering is susceptible to disturbance, reducing the barrier effect; in addition, contaminants remain in place, and neither the amount nor morphology is changed by the coverage.

Endogenous phosphorus chemical passivation is also a technique for in situ controlled release of bottom sludge phosphorus without the need to remove the bottom sludge. The technology is that passivating materials (such as silicon-based phosphorus-fixing materials, lanthanum-modified bentonite, modified zeolite and the like) which can effectively adsorb and fix phosphorus are put into lakes and reservoirs, and the materials can adsorb and fix the phosphorus covered in water in the sedimentation process and form a thin covering layer after being sunk into the lake bed. The passivating material can also control endogenous phosphorus by adsorbing phosphorus in the pore water of the bottom sludge and increasing the phosphorus fixing capacity of the bottom sludge. Because the passivation material is a material capable of effectively adsorbing and fixing phosphorus, the dosage is very low, and the engineering quantity is small. Passivation techniques may change the morphology of the phosphorus, although the amount of phosphorus is not changed. That is, the passivating material can convert phosphorus into a poorly soluble, extremely stable form, thereby persistently preventing the release of phosphorus. Thus, passivation technology is an inexpensive and widely used strategy for endogenous phosphorus control.

However, in the prior art, in addition to the problem of low adsorption capacity of common phosphorus, the prior art also has the problems of short service life and single action (only aiming at phosphorus), and as described above, endogenous phosphorus generally circulates among water, organisms and sediment in a water internal circulation manner, and a single-use passivating material can only act in the water for 20 days, and is difficult to continuously adsorb even if passivated phosphorus is not released into the water after 20 days.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: overcomes the defects of the prior art, and provides the endogenous phosphorus passivation material of the eutrophic water body, which can simultaneously fix inorganic anions such as phosphorus and the like, inorganic cations such as ammonia nitrogen and the like, organic compounds such as organic phosphorus and the like, and has low cost, large adsorption capacity and long service life, and the preparation method thereof.

The technical scheme adopted by the invention for solving the technical problem is as follows: an endogenous phosphorus passivation material for eutrophic water is characterized in that: the feed comprises the following raw materials in parts by weight: 10-20 parts of zeolite powder, 30-50 parts of kaolin, 10-15 parts of lanthanum strong acid salt, 5-10 parts of magnesium strong acid salt and 5-10 parts of alum.

Since alum used for modification is much larger in pore size than zeolite and can only be supported on the outer surface, the negative charge in the internal pores of alum modified zeolite remains available for adsorption of inorganic cations. The charge in the pores generally accounts for 80-90% of the total charge of the zeolite, so that the zeolite can still be used for efficiently removing inorganic cations such as ammonia nitrogen and the like, thereby improving the adsorption capacity and prolonging the service life of the passivation material; and after the alum is loaded on the outer surface, the lanthanum and the magnesium are promoted to migrate to the inner pores of the zeolite, the zeolite is more easily and firmly combined with lanthanum and magnesium ions in a system, and the alum and the zeolite are matched with the lanthanum and the magnesium to obtain higher adsorption capacity and longer service life. Therefore, the multifunctional endogenous phosphorus passivation material capable of synchronously fixing phosphate, ammonia nitrogen and organic pollutants (organic phosphorus, humic acid and the like) in lakes and increasing dissolved oxygen at the bottom of a water body is constructed, and meanwhile, kaolin can improve a substrate of bottom mud and can also improve the flocculation effect by cooperating with alum.

Preferably, the detergent also comprises 5-15 parts of calcium peroxide.

The calcium peroxide is not loaded on the surface of zeolite, has mild property, good safety and strong oxidability, can supplement active oxygen which is lacked in a water body, and simultaneously oxidizes substances which are harmful to the health of fishes, such as organic matters, ammonia nitrogen, sub-salt, hydrogen sulfide and the like accumulated due to insufficient oxygen supply, thereby achieving the purpose of water quality treatment, after the calcium peroxide enters the water body, the dissolved oxygen environment of bottom sludge can be obviously increased, the impurity treatment capacity of other water bodies of the endogenous phosphorus passivation material can be further improved, the ammonia nitrogen treatment capacity can be further improved by matching lanthanum and magnesium ions, other impurity ions are not introduced, and the calcium ions can also provide certain phosphorus passivation capacity, thereby achieving multiple purposes.

Preferably, the zeolite powder is subjected to sodium bicarbonate mixing and stirring treatment, and the sodium bicarbonate enables the final pH value of the endogenous phosphorus passivation material in the eutrophic water body to be 6-8.

The zeolite powder is subjected to alkaline treatment by sodium bicarbonate, the internal structure of the zeolite powder is modified, the zeolite powder is more easily combined with lanthanum and magnesium ions in a system, and more lanthanum and magnesium ions can be attached, so that the adsorption capacity and the service life of an endogenous phosphorus passivation material can be further improved, the ions are promoted to be combined with phosphate radicals to form a more stable compound, the water body treatment stability is improved, the pH can be adjusted, and the final pH of the endogenous phosphorus passivation material is ensured not to influence the environment of a water body, and the influence on the water body is reduced.

Preferably, the lanthanum strong acid salt is lanthanum chloride.

Preferably, the magnesium strong acid salt is magnesium chloride.

The chloride ions introduced by the hydrochloride have less influence on the water body, and the introduction of more water body influence elements such as nitrate radicals or sulfate radicals is avoided.

Preferably, the water-soluble paint also comprises 80-91 wt% of water.

The water is a common carrier or solvent for preparing the endogenous phosphorus passivation material in the eutrophic water body, and the optimal dosage can ensure that all effective components are fully dispersed on the premise of saving water, thereby helping the zeolite powder to be dissolved and modified.

The preparation method of the endogenous phosphorus passivation material in the eutrophic water body is characterized by comprising the following steps: the method comprises the following steps:

1) mixing water with zeolite powder and kaolin;

2) adding lanthanum strong acid salt, magnesium strong acid salt and alum, and stirring to prepare an endogenous phosphorus passivation material in the eutrophic water body;

the water consumption in the step 1) is 80-91 wt% of the endogenous phosphorus passivation material in the eutrophic water body.

Preferably, the water, the zeolite powder and kaolin in the step 1) are mixed and then added with sodium bicarbonate to modify the zeolite powder, wherein the sodium bicarbonate is used in an amount which enables the final pH value of the endogenous phosphorus passivation material in the eutrophic water body to be 6-8.

Preferably, the amount of the sodium bicarbonate is 15-20 kg of sodium bicarbonate added to per 1 cubic meter of the endogenous phosphorus passivation material in the eutrophic water body.

The zeolite powder is firstly subjected to alkaline modification of sodium bicarbonate once, and is modified in an alkaline environment, so that the zeolite powder is more easily combined with lanthanum and magnesium ions in a system, and more lanthanum and magnesium ions can be attached, and the ions are loaded on a zeolite structure, and then can be combined with phosphate radicals in water to form a stable compound, so that the stability of water body treatment is improved, the pH can be adjusted, the pH of the final endogenous phosphorus passivation material is ensured not to influence the environment of the water body, and the influence on the water body is reduced.

The whole preparation method is simple and low in cost.

The sodium bicarbonate with the optimal dosage can properly modify the zeolite powder, ensure that the pH of the final endogenous phosphorus passivation material is close to the pH of the natural water body, reduce the environmental influence and reduce the cost.

Further preferably, the step 1) is performed for 120-150 min at a speed of 100-1000 rpm.

The optimal rotation speed matching time can ensure that the sodium bicarbonate and the zeolite powder are fully reacted and modified, and simultaneously, the preparation time is shortened as much as possible.

Preferably, the stirring in the step 2) is performed for 40-60 min at a speed of 100-1000 rpm.

The preferred stirring can ensure the full adhesion of alum, lanthanum and magnesium ions on the zeolite powder, and further shorten the preparation period under the condition of ensuring the loading capacity.

Preferably, calcium peroxide is added after stirring in the step 2), and the mixture is stirred to prepare the endogenous phosphorus passivation material in the eutrophic water body.

Compared with the prior art, the invention has the following beneficial effects:

1) the endogenous phosphorus passivation material for the eutrophic water body is ecologically safe and has good compatibility with the bottom mud. When the method is applied, the alkalinity of the water body is not required to be consumed, and the physicochemical properties of the lake are not changed. The zeolite is an important constituent component of natural soil/sediment, so that the endogenous phosphorus passivation material is environment-friendly and has good environmental compatibility with lake beds and river beds.

2) The endogenous phosphorus passivation material of the present invention has versatility. Different from other passivation materials which mainly only aim at the fixation of inorganic anions and phosphate radicals, the invention has passivation functions on inorganic anions (inorganic phosphate radicals and the like), inorganic cations (ammonia nitrogen and the like) and organic compounds (organic phosphorus, humus) and can obviously improve the dissolved oxygen environment of water.

3) The passivation material has the advantages of high phosphorus adsorption capacity, multifunction, ecological safety, low cost, convenient application and short construction period. The method for restoring the eutrophic water body by combining the passivation material and the submerged plant has the advantages of low treatment cost, safety, reliability, quick response and stable treatment effect.

4) Endogenous phosphorus passivating materials can be customized for different water bodies. According to the release characteristics of inorganic anions such as inorganic phosphate radicals and the like, inorganic cations such as ammonia nitrogen and the like, organic compounds such as organic phosphorus and the like in lakes and main environmental problems, the endogenous phosphorus passivation material suitable for a specific water body can be prepared by changing the mass percentage of natural clinoptilolite powder and alum.

Drawings

FIG. 1 is a graph showing the results of morphological tests on phosphorus in the bottom sludge before and after the treatment in example 1.

FIG. 2 shows the results of the phosphorus concentration test in the overburden water before and after remediation in example 1.

Detailed Description

The present invention will be further described with reference to examples, and example 1 is a preferred example of the present invention.

Example 1

An endogenous phosphorus passivation material for eutrophic water bodies adopts a formula of natural clinoptilolite powder: kaolin: lanthanum chloride: magnesium chloride: calcium peroxide: the ratio of alum is 15:40:13:8:10: 8; the water content of the endogenous phosphorus passivation material in each 10 tons of eutrophic water is 9 tons.

A preparation method of an endogenous phosphorus passivation material of an eutrophic water body comprises the following steps:

1) mixing water, zeolite powder and kaolin, wherein the stirring speed is 200 revolutions per minute, and the stirring time is 30 minutes; adding sodium bicarbonate, wherein 18kg of sodium bicarbonate is added according to the endogenous phosphorus passivation material of each ton of eutrophic water body, the stirring speed is 200 revolutions per minute, and the stirring time is 130 minutes;

2) Adding lanthanum chloride, magnesium chloride and alum, and stirring at the speed of 200 revolutions per minute for 50 minutes;

3) and adding calcium peroxide, stirring at the speed of 200 revolutions per minute for 15 minutes to prepare the eutrophic water endogenous phosphorus passivation material, and finally, controlling the pH value of the eutrophic water endogenous phosphorus passivation material to be 6.9.

Example 2

An endogenous phosphorus passivation material for eutrophic water is prepared by adopting the following formula as follows on the basis of example 1: kaolin: lanthanum chloride: magnesium chloride: calcium peroxide: the ratio of alum was 20:30:13:8:10:8, and the other conditions were the same as in example 1.

The preparation method is the same as that of example 1.

Example 3

On the basis of the example 1, the raw material for passivating the endogenous phosphorus in the eutrophic water body is prepared by adopting the following formula: kaolin: lanthanum chloride: magnesium chloride: calcium peroxide: the ratio of alum was 15:40:10:5:10:8, and the other conditions were the same as in example 1.

The preparation method is the same as that of example 1.

Comparative example 1

On the basis of the example 1, the raw material for passivating the endogenous phosphorus in the eutrophic water body is prepared by adopting the following formula: kaolin: calcium peroxide: the ratio of alum was 20:50:10:8, lanthanum chloride and magnesium chloride were not added, and the other conditions were the same as in example 1.

The preparation method is the same as in example 1.

Comparative example 2

An endogenous phosphorus passivation material for eutrophic water is prepared by adopting the following formula as follows on the basis of example 1: lanthanum chloride: magnesium chloride: calcium peroxide: the ratio of alum was 40:10:15:10:10, kaolin was not added, and the other conditions were the same as in example 1.

The preparation method is the same as in example 1.

Comparative example 3

An endogenous phosphorus passivation material for eutrophic water is prepared by adopting the following formula as follows on the basis of example 1: kaolin: lanthanum chloride: magnesium chloride: the proportion of calcium peroxide is 15: 50: 13: 8: 13, the other conditions were the same as in example 1, except that no alum was added.

The preparation method is the same as that of example 1.

Comparative example 4

On the basis of example 1, in the preparation method of the eutrophic water endogenous phosphorus passivation material, the amount of sodium bicarbonate in step 1) is set to be 10kg, other steps and the formula are the same as those in example 1, and finally the pH value of the eutrophic water endogenous phosphorus passivation material is 5.5.

Performance testing

The method for testing the phosphorus adsorption amount comprises the following steps: weighing potassium dihydrogen phosphate to prepare 0.5mg/L phosphorus solution, taking 1000ml of the solution, adding 1ml of eutrophic water endogenous phosphorus passivation material obtained in the examples and the comparative examples, magnetically stirring to react for 48h (300 rpm), centrifuging at 4000rpm, taking the supernatant, filtering by 0.45 mu m, measuring the phosphorus concentration of the filtered water sample by using a national method for monitoring and analyzing water and wastewater (fourth edition) of soluble total phosphorus-molybdenum-antimony light resistance, setting parallel samples, and taking the average value of the two results.

The removal rate at this concentration was calculated using the following formula:

。

the method for testing the ammonia nitrogen adsorption capacity comprises the following steps: weighing ammonium chloride to prepare 0.5mg/L ammonia nitrogen solution, taking 1000ml of the solution, adding 1ml of the eutrophic water endogenous phosphorus passivation material obtained in the embodiment and the comparative example, magnetically stirring to react for 48h (300 rpm), centrifuging at 4000rpm, taking the supernatant, filtering by 0.45 mu m, measuring the ammonia nitrogen concentration of the filtered water sample by adopting a national standard method HJ/535-2009 Narse reagent method, and calculating the adsorption capacity of the endogenous phosphorus passivation material to the ammonia nitrogen according to the difference of the ammonia nitrogen concentration before and after adsorption. Parallel samples were taken and the average of the two results was taken.

The test results are given in table 1 below.

TABLE 1 Performance test results

。

And (3) practical application test: to an area of 800m²The natural water body lake has the water depth of 2.1 meters and the mud depth of 1m, and is a severely eutrophic lake. The lake is completely closed and is not connected with other water bodies.

And (3) transporting the endogenous phosphorus passivation material of the eutrophic water body obtained in the example 1 to the lakeshore completely because the lake is not large. A square plastic container with a volume of 200L was used to dose the suspension of the above materials to the lake surface.

The pump head of the submersible stirring type slurry pump is put into the material turbid liquid, and the turbid liquid is sprayed below the lake surface while stirring. The administration is divided into 3 times, and each time interval is 2 days.

After spraying, the pH, transparency and dissolved oxygen concentration are tested on site at 3, 7, 15, 30 and 60 days after spraying, and a water sample is taken and returned to a laboratory for testing the total phosphorus, dissolved inorganic phosphorus, ammonia nitrogen and dissolved oxygen concentration according to the national Water and wastewater monitoring and analysis method (fourth edition). The test results are shown in Table 2.

After the passivation technology is implemented, the pH changes little and has no obvious change trend, which indicates that the endogenous phosphorus passivation material does not change the water quality indexes obviously. However, after passivation, total phosphorus, dissolved inorganic phosphorus and ammonia nitrogen are all obviously reduced, the dissolved oxygen concentration is obviously improved, and the results are shown in table 2 after 5 times of averaging.

TABLE 2 actual application testing

。

The figure of the form test result of phosphorus in the bottom sludge before and after treatment and the test result of the phosphorus concentration in the overlying water before and after treatment are shown in the attached figures 1 and 2.

Compared with the performance test results of the embodiment 1, the comparative examples 1 to 3 and the attached figures 1 to 2 show that the zeolite, kaolin, alum, lanthanum chloride and magnesium chloride have a certain specific coordination effect, one component cannot be simply added to replace the other component, the components are mutually matched to effectively improve the adsorption capacity and the service life of the endogenous phosphorus passivation material in the final eutrophic water body, and the inorganic phosphorus passivation material has a passivation function on inorganic anions (inorganic phosphate radicals and the like), inorganic cations (ammonia nitrogen and the like) and organic compounds (organic phosphorus and humus). In contrast, in comparison with example 1, it can be seen that sodium bicarbonate provides some enhancement to the final passivation material in comparative example 4. The data in table 2 can prove that the passivation material can provide stable water body pollutant control effect for a long time.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention will still fall within the protection scope of the technical solution of the present invention.

Claims

1. An endogenous phosphorus passivation material for eutrophic water is characterized in that: the feed comprises the following raw materials in parts by weight: 10-20 parts of zeolite powder, 30-50 parts of kaolin, 10-15 parts of lanthanum strong acid salt, 5-10 parts of magnesium strong acid salt and 5-10 parts of alum.

2. The endogenous phosphorus passivation material in an eutrophic water body according to claim 1, wherein: and 5-15 parts of calcium peroxide.

3. The endogenous phosphorus passivation material in an eutrophic water body according to claim 1, wherein: and the zeolite powder is subjected to sodium bicarbonate mixing and stirring treatment, and the sodium bicarbonate enables the final pH value of the endogenous phosphorus passivation material in the eutrophic water body to be 6-8.

4. The endogenous phosphorus passivation material in an eutrophic water body according to claim 1, wherein: the lanthanum strong acid salt is lanthanum chloride.

5. The endogenous phosphorus passivation material in an eutrophic water body according to claim 1, wherein: the magnesium strong acid salt is magnesium chloride.

6. A preparation method of the eutrophic water endogenous phosphorus passivation material as recited in any one of claims 1 to 5, characterized in that: the method comprises the following steps:

1) mixing water with zeolite powder and kaolin;

2) adding lanthanum strong acid salt, magnesium strong acid salt and alum, and stirring to prepare an endogenous phosphorus passivation material of the eutrophic water body;

7. The method for preparing the endogenous phosphorus passivation material in the eutrophic water body according to claim 6, which is characterized in that: step 1), stirring for 120-150 min at 100-1000 rpm.

8. The method for preparing the endogenous phosphorus passivation material in the eutrophic water body according to claim 6, which is characterized in that: the stirring in the step 2) is carried out for 40-60 min at 100-1000 rpm.

9. The method for preparing the endogenous phosphorus passivation material in the eutrophic water body according to claim 6, which is characterized in that: step 1), adding sodium bicarbonate after mixing, uniformly mixing, and modifying zeolite powder; the final pH value of the eutrophic water endogenous phosphorus passivation material is 6-8 by the use amount of the sodium bicarbonate.

10. The method for preparing the endogenous phosphorus passivation material in the eutrophic water body according to claim 9, wherein the method comprises the following steps: the amount of the sodium bicarbonate is 15-20 kg of sodium bicarbonate added into the endogenous phosphorus passivation material in each 1 cubic meter of eutrophic water body.