A light-weight in-situ covering phosphorus control material for sediment and a preparation method and application thereof

Abstract

The application discloses a kind of lightweight bottom mud in-situ covering phosphorus control materials and preparation method and application thereof: preparation adopts stone powder, quicklime powder, gypsum powder, cement and water are mixed and stirred evenly to form slurry;Aluminum powder suspension is mixed with slurry, the slurry after mixing is poured into green body mold and formed, maintains 8-10 h, the green body with a large number of small pores is broken, and granular filter material with irregular surface is formed, and screening is carried out;Filter material sample is added into La (OH) 3 solution and ultrasonic reaction, and after washing, filtering and drying, lightweight bottom mud in-situ covering phosphorus control material is obtained.The true density of the filter material is greater than 1 g / cm 3 , and it can settle to the bottom of the water body;At the same time, its bulk density is less than 1 g / cm 3 , and it can be stably suspended and covered on the bottom mud, and at the same time, the filter material has a rough surface, high porosity and large specific surface area, which makes it easier for microorganisms to form a biofilm, so it can not only remove phosphate, but also remove ammonia nitrogen.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of water pollution treatment and prevention, and particularly relates to a light-weight in-situ covering phosphorus control material for sediment, a preparation method and application thereof. BACKGROUND

[0002] Water eutrophication is the most important water environmental problem at present, and the consequences caused by water eutrophication are very serious. The large increase in nitrogen and phosphorus content will cause explosive growth of algae, form water bloom, reduce the dissolved oxygen content of water body, and cause a large number of fish and shrimp to die, which is also the reason for water blackening. Phosphorus is the main limiting factor of lake eutrophication, and its source includes two aspects: input of exogenous phosphorus and release of endogenous phosphorus. When the water body receives the input of exogenous phosphorus, it is deposited in the sediment after a series of physical and chemical actions and migration and transformation. When the phosphorus content in the sediment accumulates to a certain amount, the sediment will release phosphorus into the overlying water, thereby forming a new pollution source. Even if the exogenous phosphorus of the water body is controlled, the sediment is disturbed by human beings, wind waves and other factors, which also promotes the morphological transformation of endogenous phosphorus, especially in shallow lakes, the sediment is more obviously affected by wind waves, lake currents and other factors, the physical disturbance caused by the physical disturbance and the biological disturbance caused by various benthic organisms will cause a large amount of sediment to be suspended, a large amount of particulate matter to enter the water body, thereby affecting the migration and transformation of endogenous phosphorus in the lake, and greatly increasing the phosphorus content in the overlying water. The phosphorus cycle between the sediment and the overlying water greatly affects the process of water eutrophication. Therefore, controlling the pollution of the water body caused by the release of phosphorus in the contaminated sediment is very important for the prevention and treatment of lake eutrophication.

[0003] The method for controlling sediment pollution can be divided into two directions, one is to degrade and eliminate the pollutants in the sediment by physical or chemical means, and the other is to fix the pollutants in the sediment so that the outward migration of phosphorus is limited. According to the two directions, the sediment remediation technology in water body is mainly divided into ex-situ remediation technology and in-situ remediation technology. The ex-situ remediation technology refers to sediment dredging, and at present, sediment dredging still has a series of problems, mainly including secondary pollution to water body and surrounding environment in the process of disposal and transportation, occupation of site, high cost, damage to benthic organisms and the like. All these cause people's attention to the in-situ control technology of sediment pollution, which refers to that the polluted sediment does not migrate in position, but in the original place, human takes measures to prevent the pollutants in the sediment from entering the overlying water, that is, to cut off the pollution way of internal pollution source. At present, the most promising in-situ remediation technology is the sediment covering technology, which has very obvious remediation effect on the polluted sediment and can effectively prevent the pollutants in the sediment from entering the water body. At present, the covering material is mainly inorganic sand and stone, which has the advantages of wide source and low price. However, it has the disadvantages of large specific gravity (easily sinking into the sediment and being covered by the sediment), small specific surface area, poor adsorption performance, difficulty in biofilm formation and small void ratio (easily causing anaerobic or facultative anaerobic environment), which leads to the fact that it cannot achieve long-term effective inhibition of sediment pollution and cannot improve water quality, so it is urgent to develop a light-weight in-situ covering phosphorus control material for sediment to solve the above problems.

[0004] Fujian Shuitou is a stone industry intensive area. Because the original mining stone is relatively large, irregular in shape and rough in surface, it needs to be cut into stone slabs and polished before use. A large amount of stone powder will be generated in the process of cutting and polishing, in addition, the cutting tool will also be worn out, and the iron-containing compounds worn off from the cutting tool will be mixed in the stone powder. The iron-containing stone powder cannot be recycled due to the influence of iron, and the pollution is more serious. At present, the stone powder is mostly recycled and stacked aside to avoid the stone powder from scattering and polluting the environment, and to improve the environmental protection of stone processing. However, the insufficient utilization of the recycled stone powder not only causes waste of materials, but also increases the cost of stone processing. Therefore, a reasonable recycling method for stone powder is urgently needed to solve the above problems. SUMMARY

[0005] In order to solve any one of the above problems, the present application provides a light-weight in-situ covering phosphorus control material for sediment and a preparation method thereof, which uses stone powder as raw material to prepare the light-weight in-situ covering phosphorus control material for sediment for water pollution control and prevention.

[0006] In order to achieve the above purpose, the present application adopts the following technical means:

[0007] The first aspect of the present application provides a preparation method of a light-weight in-situ covering phosphorus control material for sediment, comprising the following steps:

[0008] (1) Separating and collecting stone powder;

[0009] (2) respectively take 40-50 parts of stone powder, 20-30 parts of quicklime powder, 15-20 parts of gypsum powder, 10-15 parts of cement, and 3-5 parts of water to mix and stir evenly to form a slurry;

[0010] (3) prepare an aluminum powder suspension, mix the aluminum powder suspension with the slurry, and pour the mixed slurry into a green body mold to form a green body with a large number of fine pores after curing for 8-10 h;

[0011] (4) crushing the green body with a large number of fine pores to form granular filter material with irregular surfaces, and sieving;

[0012] (5) place 0.1 mol / L La(Cl)3·7H2O solution on a constant-temperature magnetic stirrer, add NaOH solution drop by drop while stirring until the pH value of the reaction solution reaches 10, then place the reaction solution in an ultrasonic cell disruptor for ultrasonic reaction, and obtain La(OH)3 loaded solution after the reactants are fully dispersed;

[0013] (6) take the filter material sample in step (4) and add it to the La(OH)3 solution for ultrasonic reaction, and after water bath reaction, the reaction solution is precipitated, the supernatant is removed, and the precipitate is washed with deionized water three times; the solid after filtration is dried to obtain the light bottom mud in-situ covering phosphorus control material.

[0014] In some embodiments of the present application, the particle size of the sieved material is 0.5-2 mm.

[0015] In some embodiments of the present application, the slurry in step (2) is heated by passing hot steam, and the temperature of the hot steam is 35-50℃.

[0016] In some embodiments of the present application, the ultrasonic reaction conditions in steps (5) and (6) are as follows: under the action of 120-140 W ultrasonic waves, the reaction is carried out for 8-20 min.

[0017] The second aspect of the present application provides a light bottom mud in-situ covering phosphorus control material, which is prepared by the method of the first aspect.

[0018] The third aspect of the present application provides the use of the light bottom mud in-situ covering phosphorus control material of the second aspect in the removal of phosphorus in overlying water.

[0019] In some embodiments of the present application, the dosage of the light bottom mud in-situ covering phosphorus control material in water is 1 g / 30 ml-1 g / 15 ml.

[0020] Advantages of the present application

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] (1) The raw material cost of the method is low, the preparation cost is low, waste is treated by waste, and good economic benefit and environmental benefit are achieved.

[0023] (2) The true density of the filter material is greater than 1 g / cm 3 , which ensures its sedimentation performance in water and enables it to settle at the bottom of the water body; at the same time, the bulk density is less than 1 g / cm 3 , which enables it to stably suspend and cover on the bottom mud and not sink into the bottom mud, and it is a good covering material.

[0024] (3) The filter material is crushed after sintering to form a granular filter material with an irregular surface, and a large number of small pores enclosed in the green body are exposed to the outside, so that it has a large specific surface area, increases the phosphate adsorption active site, and at the same time, the filter material has calcium base, iron base, aluminum base, lanthanum base and other metal cations, so that it has a large phosphate adsorption capacity; the filter material surface is rough, the porosity is high, the specific surface area is large, the microorganisms are more easily to form a biofilm, the biofilm is started quickly, not only can remove phosphate, but also can remove ammonia nitrogen.

[0025] (4) The filter material has high selectivity to phosphate by loading lanthanum hydroxide, has good treatment effect on low-concentration phosphorus contaminated water, is beneficial to the removal of overlying water phosphate; the filter material is slightly alkaline, which is beneficial to improve the acidic environment of the bottom mud; the filter material has high strength and is not easy to break, and the filter material has reasonable porosity, so as not to further deteriorate the anaerobic environment of the bottom mud. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The appearance of the bottom mud in-situ covering phosphorus control material of the present application before use is shown;

[0027] Figure 2 The biological biofilm formation state of the bottom mud in-situ covering phosphorus control material of the present application in use is shown. DETAILED DESCRIPTION

[0028] The following examples are presented herein to demonstrate preferred embodiments of the present application. Those skilled in the art will appreciate that the techniques disclosed in the following examples represent techniques discovered by the inventors to function well in the practice of the present application and can be readily adapted or modified by persons of ordinary skill in the art to be useful in other examples and applications of the present application without departing from the scope of the present application. Therefore, these examples are to be considered in a demonstrative rather than a limiting sense.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs, and the materials described herein will be referred to by the names given in the references cited herein. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the application described herein. Such equivalents are intended to be encompassed by the following claims.

[0030] The technical solutions of the patent are further described in detail below in combination with the specific embodiments.

[0031] Example 1

[0032] 40 parts of stone powder, 20 parts of quicklime powder, 15 parts of gypsum powder, 10 parts of cement, and 3.64 parts of water were weighed and mixed to form a slurry. The slurry was heated to 50°C by passing hot steam. An aluminum powder suspension was prepared, and the aluminum powder suspension was mixed with the slurry. The mixed slurry was poured into a green body mold for molding. After curing for 10 h, a green body with a large number of fine pores was formed. The green body was crushed to form granular filter material with irregular surfaces, and was sieved to a particle size of 0.5 mm.

[0033] A 0.1 mol / L La(Cl)3·7H2O solution was placed on a constant-temperature magnetic stirrer, and the stirring speed was set to 120 rpm. A 5 mol / L NaOH solution was added dropwise until the pH of the reaction solution reached 10. The reaction solution was then immediately placed in an ultrasonic cell disruptor and subjected to ultrasonic treatment at an intensity of 130 W for 5 min to disperse the reactants. A La(OH)3solution was obtained. An appropriate amount of 0.5 mm filter material was added to the La(OH)3solution and reacted under ultrasonic treatment at 130 W for 10 min, and then in a 60°C water bath for 6 h. The reaction solution was then precipitated, the supernatant was discarded, and the precipitate was washed three times with deionized water. The filtered solid was dried at 60°C, and after 48 h, the sediment in situ covering phosphorus control material 1 was obtained.

[0034] Example 2

[0035] Take 50 parts of stone powder, 30 parts of quicklime powder, 20 parts of gypsum powder, 15 parts of cement, and 3.84 parts of water respectively, mix and stir evenly to form a slurry. Heat the slurry to 35℃ by passing hot steam. Prepare an aluminum powder suspension, mix the aluminum powder suspension with the slurry, and pour the mixed slurry into a green body mold for shaping. After 8 hours of curing, a green body with a large number of fine pores is formed. The green body with a large number of fine pores is crushed to form granular filter material with irregular surface, and is sieved, with a particle size of 2 mm. Place a 0.1 mol / L La(Cl)3·7H2O solution on a constant temperature magnetic stirrer, set the rotation speed to 120 rpm, and add 5 mol / L NaOH solution dropwise until the pH value of the reaction solution reaches 10. Then immediately place the reaction solution in an ultrasonic cell disruptor and ultrasonicate at an intensity of 130 W for 5 min to disperse the reactants thoroughly, obtaining a La(OH)3-loaded solution. Take an appropriate amount of 2 mm filter material sample and add it to the La(OH)3 solution, and react for 10 min under ultrasonic action at 130 W, and then react in a 60℃ water bath for 6 h; then the reaction solution is precipitated, the supernatant is discarded, and the precipitate is washed with deionized water three times; the filtered solid is dried at 60℃, and taken out after 48 h. The bottom mud in-situ covering phosphorus control material 2 is obtained.

[0036] After performance testing of the bottom mud in-situ covering phosphorus control material prepared in Example 2, the values are obtained, and the results are shown in Table 1.

[0037] Table 1: Performance parameter table of bottom mud in-situ covering phosphorus control material

[0038]

[0039] Example 3

[0040] Without adding stone powder, take 30 parts of quicklime powder, 20 parts of gypsum powder, 15 parts of cement, and 3.84 parts of water respectively, mix and stir evenly to form a slurry, and prepare in the same way as Example 2 to obtain a control material of bottom mud in-situ covering phosphorus control material 2: bottom mud in-situ covering phosphorus control material 3, to compare the effect of raw material stone powder on total phosphorus removal: take two 100 mL water samples with a TP concentration of 5 mg / L, respectively add 2 g of bottom mud in-situ covering phosphorus control material 2 and bottom mud in-situ covering phosphorus control material 3, under the condition of oscillation frequency of 150 r / min, react for 60 min, and the reaction temperature is room temperature.

[0041] The results show that the total phosphorus removal rate of bottom mud in-situ covering phosphorus control material 2 is 92.18%, and the total phosphorus removal rate of bottom mud in-situ covering phosphorus control material 3 is 50.10%. Without adding stone powder, the phosphorus removal rate of the prepared bottom mud in-situ covering phosphorus control material decreases by 45.6%.

[0042] Example 4

[0043] The 2 mm granular filter material sample prepared in the above Example 2 was taken and compared with the lanthanum modified in-situ covering phosphorus control material 2 of the bottom mud to compare the influence of lanthanum modification on the total phosphorus removal effect: the raw water of the river was taken for the experiment, and the water quality conditions were as follows: the COD concentration was 36.69 mg / L, the total phosphorus concentration was 0.258 mg / L, and the total nitrogen concentration was 1.383 mg / L.

[0044] The 2 mm granular filter material sample and the lanthanum modified in-situ covering phosphorus control material 2 of the bottom mud were taken respectively, 150 mL of raw water sample was taken, the water sample pH was neutral, and the reaction was carried out under the condition of 200 r / min of oscillation frequency for 60 min, and the reaction temperature was room temperature. The results are shown in Table 2.

[0045] Table 2: Comparison of COD, total phosphorus and total nitrogen removal effects of two materials

[0046]

[0047] The results show that the 2 mm granular filter material sample without lanthanum modification has a certain removal effect on COD and total nitrogen, and the total phosphorus removal effect reaches 82.95%; after the lanthanum modification, the total phosphorus removal effect reaches 100%, and the lanthanum modification further increases the removal effect of the material on COD and total nitrogen.

[0048] Example 5

[0049] 150 mL of water sample with a total phosphorus concentration of 5 mg / L was taken, the water sample pH was 3, 1 g of the in-situ covering phosphorus control material 1 of the bottom mud was added, the reaction adsorption was carried out under the condition of 50 r / min of oscillation frequency for 30 min, the reaction temperature was 25°C, and the total phosphorus removal rate was 86.65%.

[0050] Example 6

[0051] 150 mL of water sample with a total phosphorus concentration of 5 mg / L was taken, the water sample pH was 5, 1 g of the in-situ covering phosphorus control material 1 of the bottom mud was added, the reaction adsorption was carried out under the condition of 100 r / min of oscillation frequency for 60 min, the reaction temperature was 30°C, and the total phosphorus removal rate was 92.34%.

[0052] Example 7

[0053] 150 mL of water sample with a total phosphorus concentration of 5 mg / L was taken, the water sample pH was 7, 1 g of the in-situ covering phosphorus control material 1 of the bottom mud was added, the reaction adsorption was carried out under the condition of 150 r / min of oscillation frequency for 90 min, the reaction temperature was 35°C, and the total phosphorus removal rate was 91.39%.

[0054] Example 8

[0055] Take total phosphorus concentration of 5mg / L water sample 150mL, water sample pH is 9, add 1g in-situ covering control phosphorus material 1, under the condition of 200r / min oscillation frequency, reaction adsorption 120min, reaction temperature is 40℃, total phosphorus removal rate is 87.36%.

[0056] Example 9

[0057] Take total phosphorus concentration of 5mg / L water sample 150mL, water sample pH is 7, add 3g in-situ covering control phosphorus material 1, under the condition of 100r / min oscillation frequency, reaction adsorption 30min, reaction temperature is 40℃, total phosphorus removal rate is 85.56%.

[0058] Example 10

[0059] Take total phosphorus concentration of 5mg / L water sample 150mL, water sample pH is 9, add 3g in-situ covering control phosphorus material 1, under the condition of 50r / min oscillation frequency, reaction adsorption 60min, reaction temperature is 35℃, total phosphorus removal rate is 98.99%.

[0060] Example 11

[0061] Take total phosphorus concentration of 5mg / L water sample 150mL, water sample pH is 3, add 3g in-situ covering control phosphorus material 1, under the condition of 200r / min oscillation frequency, reaction adsorption 90min, reaction temperature is 30℃, total phosphorus removal rate is 82.01%.

[0062] Example 12

[0063] Take total phosphorus concentration of 5mg / L water sample 150mL, water sample pH is 5, add 3g in-situ covering control phosphorus material 1, under the condition of 150r / min oscillation frequency, reaction adsorption 120min, reaction temperature is 25℃, total phosphorus removal rate is 99.47%.

[0064] Example 13

[0065] Take total phosphorus concentration of 5mg / L water sample 150mL, water sample pH is 9, add 5g in-situ covering control phosphorus material 1, under the condition of 150r / min oscillation frequency, reaction adsorption 30min, reaction temperature is 30℃, total phosphorus removal rate is 99.21%.

[0066] Example 14

[0067] Take total phosphorus concentration of 5mg / L water sample 150mL, water sample pH is 7, add 5g in-situ covering control phosphorus material 1, under the condition of 200r / min oscillation frequency, reaction adsorption 60min, reaction temperature is 25℃, total phosphorus removal rate is 100%.

[0068] Example 15

[0069] Take 150ml of water sample with total phosphorus concentration of 5mg / L, the pH of the water sample is 5, add 5g of the in-situ covering phosphorus control material 1, under the condition of oscillation frequency of 50r / min, reaction adsorption for 90min, the reaction temperature is 40℃, the total phosphorus removal rate is 99.14%.

[0070] Example 16

[0071] Take 150ml of water sample with total phosphorus concentration of 5mg / L, the pH of the water sample is 3, add 5g of the in-situ covering phosphorus control material 1, under the condition of oscillation frequency of 100r / min, reaction adsorption for 120min, the reaction temperature is 35℃, the total phosphorus removal rate is 99.58%.

[0072] The conditions and results of exploring the adsorption characteristics of the in-situ covering phosphorus control material of the bottom mud of Example 4 to Example 15 are shown in Table 3.

[0073] Table 3 Orthogonal test table of adsorption characteristics of in-situ covering phosphorus control material of bottom mud

[0074]

[0075] The results show that: according to the analysis of the orthogonal experimental results, among the five factors, the material dosage has the greatest influence on the total phosphorus removal effect, and the primary and secondary order of the influence of each factor on the total phosphorus removal effect is: material dosage, pH, oscillation frequency, adsorption time and temperature. Under the condition of material dosage 5g / 150ml, pH value of water sample 7, oscillation frequency 200(r / min), temperature 25℃ and reaction adsorption time 60min, the total phosphorus removal rate can reach 100%. It shows that the material can meet the adsorption at normal temperature in natural water body.

[0076] All the documents mentioned in the present application are cited as references in the present application, just like each document is cited as a reference individually. In addition, it should be understood that, after reading the above teaching of the present application, those skilled in the art can make various modifications or amendments to the present application, and these equivalent forms also fall within the scope defined by the present application.

Claims

1. The application of a light-weight sediment capping phosphorus control material in the prevention and control of water pollution, characterized in that: The preparation method of the light-weight bottom sludge in-situ covering phosphorus control material comprises the following steps: ​ (1) Separating and collecting the stone powder containing iron compounds; (2) Separately taking 40-50 parts of the stone powder containing iron compounds, 20-30 parts of quicklime powder, 15-20 parts of gypsum powder, 10-15 parts of cement, and 3-5 parts of water to mix and stir uniformly to form a slurry; (3) Preparing an aluminum powder suspension, mixing the aluminum powder suspension with the slurry, pouring the mixed slurry into a green body mold for molding, curing for 8-10 hours, and forming a green body with a large number of fine pores; (4) Breaking the green body with a large number of fine pores to form granular filter material with irregular surfaces, and performing screening; (5) Placing a 0.1 mol / L La(Cl)3·7H2O solution on a constant-temperature magnetic stirrer, adding NaOH solution drop by drop while stirring until the pH value of the reaction solution reaches 10, then placing the reaction solution in an ultrasonic cell disruptor for ultrasonic reaction, and obtaining a La(OH)3-loaded solution after the reactants are fully dispersed; (6) Taking the filter material sample in step (4) and adding it to the La(OH)3 solution for ultrasonic reaction, performing water bath reaction on the reaction solution, precipitating the reaction solution, removing the supernatant, washing the precipitate with deionized water three times, and drying the filtered solid to obtain the light-weight bottom sludge in-situ covering phosphorus control material; The dosage of the light-weight bottom sludge in-situ covering phosphorus control material in the water body is 1g / 30ml-1g / 15ml; The true density of the light-weight bottom sludge in-situ covering phosphorus control material is >1g / cm³, and the bulk density is <1g / cm³ The water pollution prevention and control includes total phosphorus removal, COD removal, and ammonia nitrogen removal.

2. Use according to claim 1, characterized in that, The particle size of the screened material is 0.5-2 mm.

3. Use according to claim 1, characterized in that, In step (2), the slurry is heated by passing hot steam, and the temperature of the hot steam is 35-50℃.

4. Use according to claim 1, characterized in that, In steps (5) and (6), the ultrasonic reaction conditions are as follows: under the action of 120-140W ultrasonic waves, the reaction is carried out for 8-20min.

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