CN113426402B - Preparation method and application of lanthanum-aluminum multi-element composite mineral phosphorus removal material - Google Patents
Preparation method and application of lanthanum-aluminum multi-element composite mineral phosphorus removal material Download PDFInfo
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Abstract
The invention belongs to the technical field of environmental material preparation and water quality treatment, and particularly discloses a preparation method and application of a lanthanum-aluminum multi-element composite mineral phosphorus removal material, wherein the preparation method comprises the following steps: 1) Uniformly mixing power plant ash and a non-metal mineral material, calcining for 4-5 hours at the temperature of 600-900 ℃, and cooling to room temperature to obtain a composite mineral material; 2) Grinding, sieving and drying the composite mineral material to obtain composite mineral powder; 3) And mixing the composite mineral powder with the lanthanum-aluminum modified alkali liquor to obtain a mixture, and then sequentially carrying out ultrasonic treatment, stirring, filtering and drying on the mixture to obtain the lanthanum-aluminum multi-element composite mineral phosphorus removal material. The lanthanum-aluminum multi-element composite mineral phosphorus removal material is crushed and then packaged and linked in a non-woven fabric filter bag, so that the lanthanum-aluminum multi-element composite mineral phosphorus removal material capable of being recycled can be obtained. The phosphorus removal material is applied to phosphorus-containing sewage and has a good phosphorus removal effect.
Description
Technical Field
The invention relates to the technical field of environmental material preparation and water quality treatment, in particular to a preparation method and application of a lanthanum-aluminum multi-element composite mineral phosphorus removal material.
Background
With the increasing economic development and urbanization progress, phosphate pollution in natural water systems and water eutrophication have become major environmental problems threatening various organisms. According to the 2016 publication of environmental conditions in China, it was shown that the water bodies of V-type and poor V-type account for 5.4% and 8.0% respectively in 112 major-controlled lakes (reservoirs) with monitored data. The main nutrient components causing water eutrophication comprise organic carbon, nitrogen, phosphorus, potassium and the like, the organic carbon in the sewage can be basically removed after general biological treatment, the content of other components except nitrogen and phosphorus is extremely low relative to the demand in the eutrophication occurrence process and cannot become a limiting factor of the eutrophication, therefore, the main factor causing the mass propagation of algae is nitrogen and phosphorus, the phosphorus is an important factor causing the water eutrophication, the water body polluted by the phosphorus and the algae are propagated in large quantities, the decomposition of the dead algae can cause the water body to generate musty taste and odor, many varieties can also generate toxin, and the health of human beings is influenced through a food chain, so the reduction of the phosphorus content in the sewage has important significance.
In recent years, compounds of lanthanum and aluminum have high affinity for phosphorus, and are widely applied to phosphorus removal in water. Such as lanthanum modified bentonite (Phoslock), developed by the australian federal scientific and industrial research organization (CSIRO), can reduce phosphate concentrations to trace levels. After many european lakes have been administered aluminum, the phosphorus load within the deposit can be significantly reduced. However, the single lanthanum adsorbent is greatly influenced by the organic matters in the water body, the existence of negative charges on the surface is not beneficial to attracting phosphate radicals and hydrogen phosphate radicals in the water body, and the price is high. The single aluminum modified adsorbent is easy to acidify the water body, the water body risk is high, the pH value of the used water body is more between 6 and 9, and the water body type is narrow.
In order to further reduce the cost, the development of an environment-friendly, cheap and easily available lanthanum-based and aluminum-based carrier which does not influence the dephosphorization efficiency is a main subject of current research. The power plant ash is used as the discharge of a coal-fired power plant, has large yield, low utilization rate, rich pore structure, certain adsorbability and low price and is easy to obtain. The expanded perlite has good adsorption effect on phosphorus in water due to the unique surface structure and performance, the mineral reserves of attapulgite, montmorillonite and the like are rich, the expanded perlite is widely applied to the field of environmental protection, and the heat-treated calcium-rich attapulgite (TCAP) can adsorb a certain amount of phosphorus. Therefore, the composite mineral phosphorus removal material prepared from the nonmetallic mineral material and the power plant ash by a certain technical means has certain research value.
Disclosure of Invention
Aiming at the problems and the defects in the prior art, the invention aims to provide a preparation method and application of a lanthanum-aluminum multi-element composite mineral phosphorus removal material.
Based on the purpose, the invention adopts the following technical scheme:
in a first aspect, the invention provides a preparation method of a lanthanum-aluminum multi-element composite mineral phosphorus removal material, which comprises the following steps:
(1) Uniformly mixing power plant ash and a nonmetal mineral material, calcining for 4-5 hours at the temperature of 600-900 ℃, and cooling to room temperature to obtain a composite mineral material;
(2) Grinding, sieving and drying the composite mineral material obtained in the step (1) to obtain composite mineral powder;
(3) And (3) mixing the composite mineral powder obtained in the step (2) with lanthanum-aluminum modified alkali liquor to obtain a mixture, and then sequentially carrying out ultrasonic treatment, stirring, filtering and drying on the mixture to obtain the lanthanum-aluminum multi-element composite mineral phosphorus removal material.
According to the preparation method, the non-metallic mineral material in the step (1) is preferably at least one of attapulgite and expanded perlite.
According to the preparation method, the mass ratio of the power plant ash to the nonmetal mineral materials in the step (1) is preferably 1.
According to the preparation method, preferably, the non-metallic mineral material in the step (1) is a mixture of attapulgite and expanded perlite, and the mass ratio of the attapulgite to the expanded perlite in the mixture of the attapulgite and the expanded perlite is 1; more preferably, the mass ratio of the attapulgite to the expanded perlite in the mixture of attapulgite and expanded perlite is 3.
According to the preparation method, preferably, the preparation method of the lanthanum-aluminum modified alkali liquor in the step (3) comprises the following steps: adding LaCl 3 Solution and AlCl 3 The solution is mixed evenly to obtain LaCl 3 And AlCl 3 Mixing the solution, and then adding LaCl 3 And AlCl 3 Adjusting the pH value of the mixed solution to 10-12 to obtain lanthanum-aluminum modified alkali liquor; wherein, laCl 3 And AlCl 3 LaCl in mixed solution 3 With AlCl 3 4.
According to the above preparation process, preferably, laCl 3 And AlCl 3 The concentration of the cations in the mixed solution is 0.02-0.2 mol/L. According to the preparation method, preferably, the preparation method of the lanthanum-aluminum modified alkali liquor in the step (3) comprises the following steps: in LaCl with the cation concentration of 0.02-0.2 mol/L 3 And AlCl 3 Adding NaOH or KOH solution with the concentration of 1-2 mol/L into the mixed solution, and adjusting the pH value to 10-12; wherein, laCl 3 And AlCl 3 LaCl in mixed solution 3 With AlCl 3 In a molar ratio of 4:1. 1, 1; more preferably, laCl 3 And AlCl 3 LaCl in mixed solution 3 With AlCl 3 1 is 1.
According to the above preparation method, preferably, the calcination at 850 ℃ is performed in step (1) for 4 hours.
According to the above-mentioned production method, preferably, the sieving in the step (2) is performed with a 100-200 mesh sieve; more preferably, a 150 mesh screen is used for the screening.
According to the preparation method, preferably, when the composite mineral powder is mixed with the lanthanum-aluminum modified alkali liquor in the step (3), the dosage of the lanthanum-aluminum modified alkali liquor mixed with each gram of the composite mineral powder is 30-60 mL; more preferably, the dosage of the lanthanum-aluminum modified alkali liquor mixed per gram of the composite mineral powder is 50mL.
According to the preparation method, the ultrasonic time in the step (3) is preferably 2-5 min; the stirring time is 6 to 24 hours, and the stirring speed is 120 to 150r/min; the filtration is performed by using a 0.45 mu m water system filter membrane; the drying temperature is 100-120 ℃; more preferably, the sonication time is 5min; the stirring time is 6h, and the stirring speed is 150r/min; the drying temperature was 100 ℃.
In a second aspect, the invention provides a lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared by the preparation method.
In a third aspect, the invention provides an application of the lanthanum-aluminum multi-element composite mineral phosphorus removal material in phosphorus-containing sewage treatment.
According to the application, preferably, the lanthanum-aluminum multi-element composite mineral phosphorus removal material is crushed, packaged and linked in a non-woven fabric filter bag, and then placed in phosphorus-containing sewage for phosphorus adsorption.
Compared with the prior art, the invention has the following positive beneficial effects:
(1) The method adopts the power plant ash which is the effluent of a coal-fired power plant as a raw material, mixes and calcines the power plant ash and the nonmetal mineral material to obtain a composite mineral material, then mixes and stirs the composite mineral material and the lanthanum-aluminum modified alkali liquor, and further modifies the mixture to prepare the lanthanum-aluminum multi-element composite mineral phosphorus removal material; after the power plant ash and the nonmetal mineral material are mixed and calcined, the surface active components of the power plant ash and the nonmetal mineral material have interaction, so that the adsorption, chelation and complexation of the lanthanum-aluminum multi-element composite mineral phosphorus removal material on phosphate can be improved, and the lanthanum-aluminum multi-element composite mineral phosphorus removal material has stronger phosphorus adsorption capacity.
(2) The prepared lanthanum-aluminum multi-element composite mineral phosphorus removal material is put into a non-woven fabric filter bag linked by annular fine iron wires and is immersed into a bottom mud solution containing phosphate radicals for phosphorus adsorption, so that on one hand, inorganic phosphorus in a water body is removed in the process of sinking the filter bag; on the other hand, the filter bag is covered on the surface of the bottom mud after being sunk into the water body, and continuously reacts with inorganic phosphorus endogenously released by the bottom mud to form water-insoluble precipitate, so that the aim of simultaneously removing the phosphorus in the water and the mud can be fulfilled; in addition, phosphate ions penetrate through the filter bag and are combined with the lanthanum-aluminum multi-element composite mineral phosphorus removal material to form surface precipitates, and even in an unfavorable water body environment, the filter bag can still lock phosphorus-containing precipitates in the bag, so that the phosphorus-containing precipitates are prevented from flowing along with waves, and the recessive secondary phosphorus pollution problem is avoided; and the link of the annular iron wire can realize convenient recovery and reutilization of the lanthanum-aluminum multi-element composite mineral phosphorus removal material.
(3) Compared with a commercial phosphorus locking agent, the lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared by the invention has a more effective phosphorus removal effect, and the used raw materials are abundant in reserves, cheap and easily available, environment-friendly, wide in water body adaptation, suitable for large-scale application and wide in research value.
Detailed Description
The present invention is further illustrated by the following specific examples, which do not limit the scope of the invention.
Influence of power plant ash and different nonmetallic mineral materials on lanthanum-aluminum multi-element composite mineral phosphorus removal material
In order to discuss the influence of mixing of power plant ash and different non-metallic mineral materials on the lanthanum-aluminum multi-element composite mineral phosphorus removal material, experiments of examples 1 to 3 are carried out, and the power plant ash and attapulgite, the power plant ash and expanded perlite, and the power plant ash, the attapulgite and the expanded perlite are respectively mixed to prepare the lanthanum-aluminum multi-element composite mineral phosphorus removal material. The details of examples 1 to 3 are as follows.
Example 1:
a preparation method of a lanthanum-aluminum multi-element composite mineral phosphorus removal material comprises the following steps:
(1) Placing 50g of a mixture of power plant ash and attapulgite in a muffle furnace, heating the temperature in the muffle furnace to 850 ℃ at the speed of 10 ℃/min, calcining the mixture at 850 ℃ for 4h, and cooling to room temperature after the calcination is finished to obtain a composite mineral material; wherein the mass ratio of the power plant ash to the attapulgite in the mixture of the power plant ash and the attapulgite is 1;
(2) Grinding the composite mineral material obtained in the step (1) in a mortar, sieving with a 150-mesh sieve, and drying in a drying dish to obtain composite mineral powder;
(3) 200mL of 0.1mol/LLaCl was added 3 And 0.1mol/LAlCl 3 Mixing the mixed solution and 1mol/L NaOH solution, pouring the mixed solution into a 1L volumetric flask for constant volume, performing ultrasonic oscillation for 30min to uniformly mix the mixed solution and the NaOH solution, and preparing lanthanum-aluminum modified alkali liquor with the pH = 10;
(4) Mixing the composite mineral powder obtained in the step (2) with the lanthanum-aluminum modified alkali liquor obtained in the step (3) according to the weight ratio of 1g: and mixing 50mL of the mixture to obtain a mixture, performing ultrasonic treatment on the mixture for 5min, stirring the mixture for 12h at the speed of 150r/min, performing vacuum filtration by using a 0.45-micron water system filter membrane, and drying filter residues in a vacuum drying oven at the temperature of 100 ℃ for 12h to obtain the lanthanum-aluminum multi-element composite mineral phosphorus removal material.
Example 2:
the contents of example 2 are substantially similar to example 1, except that:
50g of a mixture of power plant ash and expanded perlite in the step (1) is placed in a muffle furnace, wherein the mass ratio of the power plant ash to the expanded perlite in the mixture of the power plant ash and the expanded perlite is 1.
Example 3:
the contents of example 2 are substantially similar to example 1, except that:
taking 50g of a mixture of power plant ash, attapulgite and expanded perlite in the step (1), and placing the mixture in a muffle furnace, wherein the mass ratio of the power plant ash, the attapulgite and the expanded perlite in the mixture of the power plant ash, the attapulgite and the expanded perlite is 1.
In order to detect the phosphorus removal efficiency of the lanthanum-aluminum multi-element composite mineral phosphorus removal materials prepared in the embodiments 1 to 3, the phosphorus removal materials prepared in the embodiments 1 to 3 and a commercial phosphorus-locking agent are used for carrying out a phosphorus adsorption experiment, and the adsorption experiment specifically comprises the following steps: 0.1g of phosphorus removal material was added to 100ml of potassium dihydrogen phosphate solution with a concentration of 50mg/L, the mixture was placed on a magnetic stirrer at room temperature in the air for stirring and adsorption, the solution was filtered after 1 hour intervals, and the residual phosphorus concentration was measured in the sampled clear solution, and the results are shown in Table 1.
TABLE 1 adsorption results of La-Al multi-component composite mineral phosphorus removal material prepared from different non-metallic mineral materials and commercial phosphorus-locking agent
As can be seen from table 1, the phosphorus removal effect of the lanthanum-aluminum multi-element composite mineral phosphorus removal material obtained by mixing attapulgite and power plant ash is better than that of the lanthanum-aluminum multi-element composite mineral phosphorus removal material obtained by mixing expanded perlite and power plant ash under the same mixing ratio, but the phosphorus removal effect of the lanthanum-aluminum multi-element composite mineral phosphorus removal material obtained by mixing power plant ash, attapulgite and expanded perlite is slightly better than that of the phosphorus removal material obtained by binary mixing, which may be because the surface active components interact after different non-metallic minerals and power plant ash are mixed and calcined, and the adsorption, chelating and complexing effects of the lanthanum-aluminum multi-element composite mineral phosphorus removal material on phosphate are increased. Meanwhile, as can be seen from table 1, the phosphorus removal effect of the lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared by the invention is better than that of the commercial phosphorus locking agent under the same conditions.
(II) influence of different amounts of power plant ash, attapulgite and expanded perlite on lanthanum-aluminum multi-element composite mineral phosphorus removal material
In order to discuss the influence of the using amounts of the power plant ash, the attapulgite and the expanded perlite on the lanthanum-aluminum multi-element composite mineral phosphorus removal material, experiments of examples 4 to 6 are carried out, and the power plant ash, the attapulgite and the expanded perlite in different proportions are respectively mixed to prepare the lanthanum-aluminum multi-element composite mineral phosphorus removal material. Specific contents of examples 4 to 6 are as follows.
Example 4:
a preparation method of a lanthanum-aluminum multi-element composite mineral phosphorus removal material comprises the following steps:
(1) Placing 50g of a mixture of power plant ash, attapulgite and expanded perlite in a muffle furnace, heating the temperature in the muffle furnace to 850 ℃ at a speed of 10 ℃/min, calcining the mixture at 850 ℃ for 4h, and cooling to room temperature after the calcination is finished to obtain a composite mineral material; wherein the mass ratio of the power plant ash, the attapulgite and the expanded perlite in the mixture of the power plant ash, the attapulgite and the expanded perlite is 1;
(2) Grinding the composite mineral material obtained in the step (1) in a mortar, sieving with a 150-mesh sieve, and drying in a drying dish to obtain composite mineral powder;
(3) 200mL of 0.1mol/LLaCl was added 3 And 0.1mol/LAlCl 3 Mixing the mixed solution and 1mol/L NaOH solution, pouring the mixed solution into a 1L volumetric flask for constant volume, and performing ultrasonic oscillation for 30min to uniformly mix the mixed solution and the NaOH solution to obtain lanthanum-aluminum modified alkali liquor with the pH = 10;
(4) Mixing the composite mineral powder obtained in the step (2) with the lanthanum-aluminum modified alkali liquor obtained in the step (3) according to the weight ratio of 1g: and mixing 50mL of the mixture to obtain a mixture, performing ultrasonic treatment on the mixture for 5min, stirring the mixture for 12h at the speed of 150r/min, performing vacuum filtration by using a 0.45-micron water system filter membrane, and drying filter residues in a vacuum drying oven at the temperature of 100 ℃ for 12h to obtain the lanthanum-aluminum multi-element composite mineral phosphorus removal material.
Example 5:
the contents of example 5 are substantially the same as example 4, except that:
in the step (1), the mass ratio of the power plant ash, the attapulgite and the expanded perlite in the mixture of the power plant ash, the attapulgite and the expanded perlite is 1.
Example 6:
the contents of example 6 are substantially the same as those of example 4, except that:
in the step (1), the mass ratio of the power plant ash, the attapulgite and the expanded perlite in the mixture of the power plant ash, the attapulgite and the expanded perlite is 1.
In order to detect the phosphorus removal efficiency of the lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared from different amounts of power plant ash, attapulgite and expanded perlite, the invention uses the lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared in the embodiments 3 and 4 to 6 and a commercial phosphorus locking agent to carry out a phosphorus adsorption experiment, and the adsorption experiment specifically comprises the following steps: 0.5g of phosphorus removal material and commercial phosphorus locking agent are respectively added into 100ml of potassium dihydrogen phosphate solution with the concentration of 10mg/L, the solution is placed on a magnetic stirrer at room temperature in the air for stirring and adsorption, the solution is filtered after 1h, and the residual phosphorus concentration is measured by sampling clear liquid, and the result is shown in table 2.
Table 2 adsorption results of lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared by different mass ratios and commercial phosphorus-locking agent
As can be seen from table 2, in the composite mineral phosphorus removal material, the formula with more attapulgite content has a relatively better effect of removing phosphorus from a water body, and the formula with more expanded perlite has a slightly inferior effect of removing phosphorus, and with the increase of the proportion of the attapulgite content, the phosphorus removal performance of the lanthanum-aluminum multi-element composite mineral phosphorus removal material is improved, and a certain proportion of attapulgite may be added, so that the optimization of the particle size ratio of the composite mineral phosphorus removal material is facilitated.
(III) influence of different stirring time of the composite mineral powder and the lanthanum-aluminum modified alkali liquor on the lanthanum-aluminum multi-element composite mineral phosphorus removal material
In order to discuss the influence of different stirring times of the composite mineral powder and the lanthanum-aluminum modified alkali liquor on the lanthanum-aluminum multi-element composite mineral phosphorus removal material, the experiments of examples 7 to 8 are carried out, and the composite mineral powder and the lanthanum-aluminum modified alkali liquor are respectively mixed and stirred for different times to prepare the lanthanum-aluminum multi-element composite mineral phosphorus removal material. The details of examples 7 to 8 are as follows.
Example 7:
a preparation method of a lanthanum-aluminum multi-element composite mineral phosphorus removal material comprises the following steps:
(1) Placing 50g of a mixture of power plant ash, attapulgite and expanded perlite in a muffle furnace, heating the temperature in the muffle furnace to 850 ℃ at a speed of 10 ℃/min, calcining the mixture at 850 ℃ for 4h, and cooling to room temperature after the calcination is finished to obtain a composite mineral material; wherein the mass ratio of the power plant ash, the attapulgite and the expanded perlite in the mixture of the power plant ash, the attapulgite and the expanded perlite is 1;
(2) Putting the composite mineral material obtained in the step (1) into a mortar for grinding, then sieving with a 150-mesh sieve, and drying in a drying dish to obtain composite mineral powder;
(3) 200mL of 0.1mol/LLaCl was added 3 And 0.1mol/LAlCl 3 Mixing the mixed solution and 1mol/L NaOH solution, pouring the mixed solution into a 1L volumetric flask for constant volume, and performing ultrasonic oscillation for 30min to uniformly mix the mixed solution and the NaOH solution to obtain lanthanum-aluminum modified alkali liquor with the pH of = 10;
(4) Mixing the composite mineral powder obtained in the step (2) with the lanthanum-aluminum modified alkali liquor obtained in the step (3) according to the weight ratio of 1g: and mixing 50mL of the mixture to obtain a mixture, performing ultrasonic treatment on the mixture for 5min, stirring the mixture for 6h at the speed of 150r/min, performing vacuum filtration by using a 0.45-micron water system filter membrane, and drying filter residues in a vacuum drying oven at the temperature of 100 ℃ for 12h to obtain the lanthanum-aluminum multi-element composite mineral phosphorus removal material.
Example 8:
the contents of example 8 are substantially the same as those of example 7, except that:
in the step (4), after the mixture is subjected to ultrasonic treatment for 5min, stirring is carried out for 24h at the speed of 150 r/min.
In order to detect the phosphorus removal efficiency of the lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared by the composite mineral powder and the lanthanum-aluminum modified alkali liquor in different stirring times, phosphorus adsorption experiments are carried out by using the lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared in the embodiments 3, 7 and 8 and a commercial phosphorus locking agent, and the adsorption experiments specifically comprise the following steps: 0.5g of phosphorus removal material and commercial phosphorus locking agent are respectively added into 100ml of potassium dihydrogen phosphate solution with the concentration of 10mg/L, the solution is placed on a magnetic stirrer at room temperature in the air for stirring and adsorption, the solution is filtered after 1h, and the residual phosphorus concentration is measured by sampling clear liquid, and the result is shown in table 3. Table 3 adsorption results of lanthanum-aluminum multi-element composite mineral phosphorus removal material and commercial phosphorus locking agent prepared by different stirring times of composite mineral powder and lanthanum-aluminum modified alkali liquor
As can be seen from Table 3, the stirring time has little influence on the phosphorus removal material of the lanthanum-aluminum multi-component composite mineral. The impregnation of the composite mineral in the lanthanum-aluminum modified alkali liquor comprises two processes of forming lanthanum hydroxide/aluminum precipitate and depositing the lanthanum hydroxide/aluminum on the surface of the composite mineral. Too short stirring time can cause incomplete cation precipitation or uneven distribution of lanthanum-aluminum multi-element precipitates on the surface of the composite mineral, thereby influencing the adsorption effect of the lanthanum-aluminum multi-element precipitates on phosphate. After the stirring time of 6 hours, the phosphorus removal rate reaches 99.7 percent, which indicates that the lanthanum-aluminum multi-element precipitate is basically formed and uniformly distributed on the surface of the composite mineral, and the stirring time is continuously increased, the phosphorus removal rate is over 99 percent, the phosphorus removal effect is superior to that of the commercial phosphorus-locking agent, and the stirring time is not more than 6 hours in consideration of system errors and time cost.
Influence of dosage ratios of lanthanum-aluminum modified alkali liquor and composite mineral powder on phosphorus removal effect of lanthanum-aluminum multi-element composite mineral phosphorus removal material
In order to study the influence of the dosage ratios of the lanthanum-aluminum modified alkaline solution and the composite mineral powder on the phosphorus removal effect of the lanthanum-aluminum multi-element composite mineral phosphorus removal material, experiments of examples 9 to 11 were performed, and the composite mineral powder and the lanthanum-aluminum modified alkaline solution were mixed according to different dosage ratios to prepare the lanthanum-aluminum multi-element composite mineral phosphorus removal material. Specific contents of examples 9 to 11 are as follows.
Example 9:
the contents of example 9 are substantially the same as those of example 7, except that:
in the step (4), mixing the composite mineral powder obtained in the step (2) and the lanthanum-aluminum modified alkali liquor obtained in the step (3) according to the weight ratio of 1g:30mL of the mixture was mixed to obtain a mixture.
Example 10:
the contents of example 10 are substantially the same as those of example 7, except that:
in the step (4), mixing the composite mineral powder obtained in the step (2) and the lanthanum-aluminum modified alkali liquor obtained in the step (3) according to the weight ratio of 1g:40mL of the resulting solution was mixed to obtain a mixture.
Example 11:
the contents of example 11 are substantially the same as those of example 7, except that:
in the step (4), mixing the composite mineral powder obtained in the step (2) and the lanthanum-aluminum modified alkali liquor obtained in the step (3) according to the weight ratio of 1g:60mL of the mixture was mixed to obtain a mixture.
In order to study the influence of the dosage ratio of the lanthanum-aluminum modified alkali liquor and the composite mineral powder on the phosphorus removal effect of the lanthanum-aluminum multi-element composite mineral phosphorus removal material, phosphorus adsorption experiments are performed on the lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared in the embodiment 7 and the embodiments 9 to 11, and the specific experimental steps of the phosphorus adsorption experiments are as follows: 0.1g of phosphorus removal material was added to 100ml of 10mg/L potassium dihydrogen phosphate solution, the mixture was placed on a magnetic stirrer at room temperature in the air for stirring and adsorption, the solution was filtered after 1 hour intervals, and the sample was taken to measure the residual phosphorus concentration, the results are shown in Table 4.
TABLE 4 adsorption results of phosphorus removal materials prepared with different dosage ratios of La-Al modified alkali solution to composite mineral powder
As can be seen from Table 4, the phosphorus removal rate of the lanthanum-aluminum multi-element composite mineral phosphorus removal material gradually increases as the dosage of the lanthanum-aluminum modified alkali solution is gradually increased. The dosage ratio of the composite mineral powder to the lanthanum-aluminum modified alkali liquor is 1g: when the volume of the composite mineral powder is 30ml, the phosphorus removal rate is 85.5 percent, and when the dosage ratio of the composite mineral powder to the lanthanum-aluminum modified alkali liquor is reduced to 1g: when the phosphorus removal rate is 50ml, the phosphorus removal rate is increased to 99.7%, and then the dosage ratio of the composite mineral powder to the lanthanum-aluminum modified alkali liquor is reduced, so that the phosphorus removal effect is not greatly improved. The dosage ratio of the composite mineral powder to the lanthanum-aluminum modified alkali liquor is an important index influencing the economic cost of modification, and the larger dosage ratio of the composite mineral powder to the lanthanum-aluminum modified alkali liquor can undoubtedly increase the economic cost and influence the practical application of modification. Due to the increase of the dosage of lanthanum and aluminum, active substances loaded on the composite mineral are correspondingly increased, and the active substances have good adsorption effect on phosphate, which is also the reason that the dosage ratio of the composite mineral powder to the lanthanum and aluminum modified alkali liquor is reduced to increase the removal effect of the phosphate.
Influence of pH value of lanthanum-aluminum modified alkali liquor on phosphorus removal effect of phosphorus removal material
In order to research the influence of the pH value of the lanthanum-aluminum modified alkaline solution on the phosphorus removal effect of the lanthanum-aluminum multi-element composite mineral phosphorus removal material, experiments of example 12 and example 13 are carried out, and the lanthanum-aluminum multi-element composite mineral phosphorus removal material is prepared by respectively mixing composite mineral powder and the lanthanum-aluminum modified alkaline solution with different pH values. The details of example 12 and example 13 are as follows.
Example 12:
the contents of example 12 are substantially the same as those of example 7, except that:
in the step (3), the dosage of the 1mol/L NaOH solution is adjusted to prepare the lanthanum-aluminum modified alkali liquor with the pH of = 11.
Example 13:
the contents of example 13 are substantially the same as those of example 7, except that:
in the step (3), the amount of the 1mol/L NaOH solution is adjusted to prepare the lanthanum-aluminum modified alkali liquor with the pH = 12.
In order to study the influence of the pH value of the lanthanum-aluminum modified alkali liquor on the phosphorus removal effect of the lanthanum-aluminum multi-component composite mineral phosphorus removal material, the lanthanum-aluminum multi-component composite mineral phosphorus removal material prepared in the embodiment 7, the embodiment 12 and the embodiment 13 is subjected to an adsorption experiment, and the specific experimental steps of the adsorption experiment are as follows: 0.1g of phosphorus removal material was added to 100ml of 10mg/L potassium dihydrogen phosphate solution, the mixture was placed on a magnetic stirrer at room temperature in the air for stirring and adsorption, the solution was filtered after 1 hour intervals, and the sample was taken to measure the residual phosphorus concentration, the results are shown in Table 5.
TABLE 5 influence of the pH value of the La-Al modified alkali solution on the phosphorus removal effect of phosphorus removal material
As can be seen from Table 5, the pH value of the lanthanum-aluminum modified alkaline solution is within the range of 10-12, the phosphorus removal rate of the lanthanum-aluminum multi-element composite mineral phosphorus removal material is high, and is more than 99.5%, which means that the surface of the composite mineral is richer in hydroxyl group under the alkaline condition and can be combined with positive charges in the modified solution, so that lanthanum-aluminum ions in the modified solution are easy to settle down, a precipitate and a coordination complex are generated, and the phosphorus removal effect of the lanthanum-aluminum multi-element composite mineral phosphorus removal material is enhanced.
Influence of lanthanum-aluminum multi-element composite mineral phosphorus removal material on adsorption of different initial phosphorus concentrations
In order to research the adsorption effect of the lanthanum-aluminum multi-element composite mineral phosphorus removal material on different initial phosphorus concentrations, the lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared in example 3 is respectively added into potassium dihydrogen phosphate solutions with the concentrations of 1mg/L, 10mg/L and 50mg/L to carry out an adsorption experiment, and the specific steps are as follows: 0.1g of each of the lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared in example 3 and the commercial phosphorus locking agent was added to 100ml of potassium dihydrogen phosphate solution with the concentration of 1mg/L, 10mg/L and 50mg/L respectively, the solution was placed on a magnetic stirrer at room temperature in the air and stirred for adsorption, the solution was filtered after 1 hour, and the residual phosphorus concentration was measured in the sampled clear solution, and the results are shown in Table 6.
TABLE 6 adsorption results of La-Al multi-element composite mineral phosphorus removal material on different initial phosphorus concentrations
As can be seen from table 6, as the initial phosphorus concentration increases, the phosphorus removal rate of the lanthanum-aluminum multi-component composite mineral phosphorus removal material slightly decreases, but the decrease is small, when the initial phosphorus concentration is increased from 10mg/L to 50mg/L, the phosphorus removal rate of the lanthanum-aluminum multi-component composite mineral phosphorus removal material only decreases from 99.9% to 96.2%, while the commercial phosphorus-locking agent has a good phosphorus removal effect under low-concentration phosphorus, when the phosphorus concentration increases to 50mg/L, the phosphorus removal rate sharply decreases because when the dosage of the phosphorus removal material is unchanged, the unsaturated adsorption sites on the surface of the phosphorus removal material are constant, and the higher the phosphorus concentration is, the fewer the non-adsorbed unsaturated sites are, therefore, when the commercial phosphorus-locking agent has a higher phosphorus concentration, the non-adsorbed sites on the surface of the commercial phosphorus-locking agent rapidly decrease, and the adsorption sites on the surface of the lanthanum-aluminum multi-component composite mineral phosphorus removal material still have a large amount of surplus.
(VII) influence of different lanthanum-aluminum multi-element composite mineral phosphorus removal material adding amounts on phosphorus adsorption
In order to research the phosphorus adsorption effect of different dosages of the lanthanum-aluminum multi-component composite mineral phosphorus removal material, the lanthanum-aluminum multi-component composite mineral phosphorus removal material prepared in example 3 is used for carrying out an adsorption experiment on phosphorus, and the specific experimental steps are as follows: 0.1g, 0.5g and 1g of the phosphorus removal material prepared in example 3 were added to 100ml of 10mg/L potassium dihydrogen phosphate solution, the solution was placed on a magnetic stirrer at room temperature in the air for stirring and adsorption, the solution was filtered after 1 hour interval, and the sample was taken to measure the residual phosphorus concentration, and the results are shown in Table 7.
TABLE 7 adsorption results of phosphorus adsorption results of different dosage amounts of lanthanum-aluminum multi-element composite mineral phosphorus removal materials
As can be seen from table 7, when the initial phosphorus concentration is kept unchanged, the dosage of the lanthanum-aluminum multi-element composite mineral phosphorus removal material is increased, the phosphorus removal rate does not change greatly, and is close to 100% of phosphorus removal rate, mainly because when the phosphorus concentration is unchanged, the dosage of the lanthanum-aluminum multi-element composite mineral phosphorus removal material is more, unsaturated adsorption sites on the surface of the lanthanum-aluminum multi-element composite mineral phosphorus removal material are also increased, although the unit adsorption capacity is reduced, the increase of the total adsorption sites can increase the total amount of adsorbed phosphorus, and the dosage of 0.1g can meet the requirement of efficient adsorption of phosphate, so the dosage is increased, and the improvement effect of the phosphorus removal rate is not obvious.
In addition, the lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared by the invention is immersed into the bottom mud solution containing phosphate radical through the non-woven fabric filter bag connected by the annular fine iron wire, so that on one hand, inorganic phosphorus in a water body is removed in the process of sinking the filter bag; on the other hand, the water body is immersed and then covers the surface of the bottom mud, and the water body continuously reacts with inorganic phosphorus released from the bottom mud endogenously to form water-insoluble precipitate, so that the aim of controlling the cement uniformly is fulfilled; phosphate ions are combined with the multi-element composite mineral phosphorus removal material through the filter bag to form surface sediment, and the filter bag can lock the phosphorus-containing sediment in the bag in a unfavorable water body environment, so that the phosphorus-containing sediment is prevented from flowing along with waves, and the recessive secondary phosphorus pollution problem is avoided; the linkage of the annular iron wire is beneficial to the recovery and the reutilization of the multi-element composite mineral phosphorus removal material.
Claims (6)
1. A preparation method of a lanthanum-aluminum multi-element composite mineral phosphorus removal material is characterized by comprising the following steps:
(1) Uniformly mixing power plant ash and a nonmetal mineral material, calcining for 4-5 hours at the temperature of 600-900 ℃, and cooling to room temperature to obtain a composite mineral material; the non-metal mineral material is a mixture of attapulgite and expanded perlite, and the mass ratio of the attapulgite to the expanded perlite in the mixture of the attapulgite and the expanded perlite is (1); the mass ratio of the power plant ash to the nonmetallic mineral material is 1;
(2) Grinding, screening and drying the composite mineral material obtained in the step (1) to obtain composite mineral powder;
(3) Mixing the composite mineral powder obtained in the step (2) with lanthanum-aluminum modified alkali liquor to obtain a mixture, and then sequentially carrying out ultrasonic treatment, stirring, filtering and drying on the mixture to obtain a lanthanum-aluminum multi-element composite mineral phosphorus removal material; when the composite mineral powder is mixed with the lanthanum-aluminum modified alkali liquor, the dosage of the lanthanum-aluminum modified alkali liquor mixed with the composite mineral powder per gram is 50-60 mL;
the preparation method of the lanthanum-aluminum modified alkali liquor comprises the following steps: adding LaCl 3 Solution and AlCl 3 After the solution is mixed evenly, laCl is obtained 3 And AlCl 3 Mixing the solution, and then adding LaCl 3 And AlCl 3 Adjusting the pH value of the mixed solution to 10-12 to obtain the lanthanum-aluminum modified alkali liquor.
2. The method according to claim 1, wherein the LaCl is present in step (3) 3 And AlCl 3 LaCl in mixed solution 3 With AlCl 3 The molar ratio of (a) to (b) is 4.
3. The method of claim 2, wherein the LaCl is 3 And AlCl 3 The concentration of the cations in the mixed solution is 0.02-0.2 mol/L.
4. The preparation method according to claim 1, wherein the ultrasonic time in the step (3) is 2 to 5min; the stirring time is 6 to 24 hours, and the stirring speed is 120 to 150r/min; the filtration is carried out by using a 0.45 mu m water system filter membrane; the drying temperature is 100-120 ℃.
5. A lanthanum-aluminum multi-element composite mineral phosphorus removal material prepared by the preparation method of any one of claims 1 to 4.
6. The application of the lanthanum-aluminum multi-element composite mineral phosphorus removal material disclosed by claim 5 in treatment of phosphorus-containing sewage.
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