CN115591527A

CN115591527A - Phosphorus removal particle adsorbent and preparation method and application thereof

Info

Publication number: CN115591527A
Application number: CN202111403502.5A
Authority: CN
Inventors: 钟家有; 李威; 代涛涛; 周; 刘金福; 楼倩; 傅群; 钟燮; 胡淑芳; 陈楠
Original assignee: Nanchang Institute of Technology; Jiangxi Academy of Water Resources
Current assignee: Nanchang Institute of Technology; Jiangxi Academy of Water Resources
Priority date: 2021-11-22
Filing date: 2021-11-22
Publication date: 2023-01-13
Anticipated expiration: 2041-11-22
Also published as: CN115591527B

Abstract

The invention discloses a phosphorus removal granular adsorbent and a preparation method and application thereof. The phosphorus removal particle adsorbent comprises the following raw materials in parts by weight: 1 part of calcium hydroxide, 6.5-8.5 parts of red soil and 0.5-2.5 parts of bentonite; the compound fertilizer is prepared by mixing and granulating the raw materials. The phosphorus removal granular adsorbent provided by the invention has the advantages of wide raw material source, low cost, simple preparation method, low energy consumption, no secondary pollution, good phosphorus removal effect and wide pH application range, and can be produced in a large scale for phosphorus removal of water bodies.

Description

Phosphorus removal particle adsorbent and preparation method and application thereof

Technical Field

The invention belongs to the field of water body phosphorus removal, and particularly relates to a phosphorus removal granular adsorbent and a preparation method and application thereof.

Background

Water eutrophication has become one of the major environmental problems to be solved urgently in the world today. Phosphorus is a main limiting nutrient element in a fresh water ecological system, and the biomass of algae is generally in positive correlation with the phosphorus concentration of a water body, so that the reduction of the phosphorus concentration of the water body is an important component for the eutrophication control of the water body, and the method is an effective method for inhibiting the growth of harmful algae. When the import of exogenous phosphorus in lakes and reservoirs is effectively restrained, the pollution control of the water body and endogenous phosphorus in the sediment directly determines the treatment effect of eutrophication.

The adsorption method is widely applied to the control of the eutrophic water phosphorus and has the advantages of high efficiency, economy, easy operation and the like. Although the phosphorus adsorption effect of the conventional metal (such as iron, aluminum, manganese, lanthanum and the like) modified phosphorus removal adsorbent is good, the release of metal ions in a water body has certain harm to the health of aquatic organisms. The commercial phosphorus-locking agent (B) is used more on the market

The formula is 5 percent of lanthanum and 95 percent of bentonite, although the dephosphorization effect is good, the used rare earth element lanthanum has high cost, has certain harm to aquatic organisms, has narrow pH application range, and only has the effect under the weakly acidic and neutral conditions (the pH is 5-7)Preferably, the adsorption capacity of the fertilizer to phosphorus is sharply reduced under alkaline conditions, and the field eutrophic water body (especially the water body with high algae content) is generally alkaline. Therefore, an efficient phosphorus removal adsorbent with low cost, high ecological safety and wide pH application range is urgently needed to be found.

Disclosure of Invention

The invention aims to solve the defects of the prior art and provides a phosphorus removal granular adsorbent which comprises the following raw materials in parts by weight: 1 part of calcium hydroxide, 6.5-8.5 parts of red soil and 0.5-2.5 parts of bentonite.

Preferably, the raw materials of the phosphorus removal particle adsorbent comprise, by weight: 1 part of calcium hydroxide, 8 parts of red soil and 1 part of bentonite. Or 1 part of calcium hydroxide, 8.5 parts of red soil and 0.5 part of bentonite. Or 1 part of calcium hydroxide, 6.5 parts of red soil and 2.5 parts of bentonite.

The inventor finds that the phosphorus removal granular adsorbent prepared from the calcium hydroxide, the red soil and the bentonite in a specific ratio can play a good phosphorus removal effect under a wider pH condition, and the phosphorus removal effect of the granular adsorbent is also superior to that of the traditional commercial phosphorus-locking agent

In addition, calcium hydroxide belongs to an alkaline reagent, the pH of a water body is too high due to high content of the calcium hydroxide, aquatic organisms can be damaged, and the calcium hydroxide in the adsorbent only accounts for 10% of the weight of the calcium hydroxide and is relatively safe; the red soil is weakly acidic, can neutralize the alkalinity of calcium hydroxide and water to a certain extent, and is rich in aluminum and iron, so that the phosphorus removal particle adsorbent has a certain flocculation precipitation effect; after the bentonite is added, the dephosphorization effect of the dephosphorization particle adsorbent can be improved, and the strength of the dephosphorization particle adsorbent can be enhanced due to certain viscosity, so that the dephosphorization particle adsorbent cannot be easily dispersed in a water body to cause turbidity of the water body due to disturbance. Meanwhile, the phosphorus removal particle adsorbent is used as a particle material and can also be covered on the bottom sediment, so that the bottom sediment can be prevented from being resuspended, the constraint capacity of the sediment on phosphorus is increased, the stability of the sediment is increased, the release of endogenous phosphorus is inhibited, and the diffusion of dissolved oxygen in a water body to the bottom sediment can not be prevented by pores among the particles。

The preparation method of the dephosphorization particle adsorbent comprises the following steps: mixing the raw materials and granulating. Preferably, the mixture is granulated and sieved to obtain the granular adsorbent with the grain diameter of 1-5 mm. Preferably, after sieving, drying for 24h at 40-65 ℃, and sealing.

The beneficial effects of the invention are as follows: the phosphorus removal granular adsorbent provided by the invention has the advantages of wide raw material source, low cost, simple preparation method, low energy consumption, no secondary pollution, good phosphorus removal effect and wide pH application range, and can be produced in a large scale for phosphorus removal of water bodies.

Drawings

FIG. 1 is a graph showing the relationship between the amount of adsorbent added and the phosphorus removal rate;

FIG. 2 is a graph showing the relationship between sorbent and phosphorus removal at different pH's;

FIG. 3 is a graph showing the one-week change in the removal rate of total phosphorus and soluble phosphorus from eutrophic lake water.

Detailed Description

The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments and the accompanying drawings to fully understand the objects, aspects and effects of the present invention.

Example 1:

weighing 4.8kg of red soil powder, 0.6kg of bentonite powder and 0.6kg of calcium hydroxide powder, adding the red soil powder, the bentonite powder and the calcium hydroxide powder into a disc granulator, fully mixing, adding 1.6L of water, adjusting the rotation speed of a rotor to 1600rpm and the rotation speed of the granulation disc to 50rpm, running for 12min, screening particles with the particle size of 2-3mm, drying in a 65-DEG C constant-temperature air blast drying oven for 24h to obtain the dephosphorizing particle adsorbent, and filling the dephosphorizing particle adsorbent into a plastic bottle for sealing for later use.

Example 2:

setting up a comparative experiment, setting up as shown in Table 1, wherein 1 part in Table 1 represents 0.6kg, CRB22 is the dephosphorizing granular adsorbent of example 1, and each formula in Table 1 is prepared according to the conditions of example 1 (except PL2, R2 and B2); wherein PL2 is a commercial phosphorus-locking agent (lanthanum 5%, bentonite 95%, available from Jiangsu Jinxin environmental engineering Co., ltd.), and the particle size of the adsorbent obtained by each formula in Table 1 is 2-3mm.

TABLE 1

The solution with the phosphorus concentration of 5mg/L is prepared by adopting monopotassium phosphate, and the pH value is adjusted to 7 by adopting 0.1mol/L HCl solution and 0.1mol/L NaOH solution. Then weighing the adsorbents in the table 1, respectively adding the adsorbents into 200mL of phosphorus solution (the addition amount is 0.5 g/L), setting 2 times of repetition, and placing the solution on a shaking table; the table was set at 200rpm,24h. And finally, filtering the reaction solution by using a 0.45-micron glass fiber filter membrane, and measuring the phosphorus content of the stock solution and the phosphorus content after adsorption to obtain the removal rate, wherein the results are shown in table 2.

TABLE 2

(Code)	Removal rate of
		R2	3.98％
CRB12	91.52％
		CRB22	95.15％
CRB221	98.90％
		CRB224	98.45％
CRB32	89.76％
		CRB42	72.83％
CRB52	71.14％
		CRB62	79.08％
B2	2.99％
		PL2	85.06％

As can be seen from Table 2, red soil (i.e., R2) and bentonite (i.e., B2) have almost no phosphorus removal effect by themselves; the adsorbents (namely CRB12 and CRB 62) obtained by respectively matching the red soil and the bentonite with the calcium hydroxide can greatly improve the removal rate of phosphorus.

In addition, the inventor also finds that when red soil, bentonite and calcium hydroxide are adopted, the weight ratio is (6.5-8.5): (0.5-2.5): a mass ratio of 1 when formed into a granular adsorbent such as CRB22, CRB221 and CRB224 showed an adsorption efficiency further improved compared to that of CRB12, CRB62 and commercial stabilized phosphorus agent PL2.

However, when red soil, bentonite and calcium hydroxide are mixed in other proportions to form the granular adsorbent (namely, CRB32, CRB42 and CRB 52), the adsorption efficiency is lower than that of the adsorbent (namely, CRB12 and CRB 62) formed by respectively mixing red soil and bentonite with calcium hydroxide.

In order to more intuitively show the effect, the inventor forms a graph of the adsorption effect of CRB12, CRB22, CRB32, CRB42, CRB52 and CRB62 with different addition amounts, as shown in fig. 1, it can be intuitively shown that the adsorption efficiency of CRB22 is further improved compared with that of CRB12 and CRB62, and when red soil, bentonite and calcium hydroxide are adopted to form the granular adsorbent (i.e. CRB32, CRB42 and CRB 52) in other proportions, the adsorption efficiency is lower than that of the adsorbent (i.e. CRB12 and CRB 62) formed by the coordination of the red soil and the bentonite and the calcium hydroxide respectively, which is quite unexpected.

In addition, a solution with a phosphorus concentration of 10mg/L was prepared using potassium dihydrogen phosphate, and the pH was adjusted to 7 using a 0.1mol/L HCl solution and a 0.1mol/L NaOH solution. Then, the adsorbents in table 1 were weighed and added to 200mL of phosphorus solution (each added amount was 0.5 g/L) for 2 repetitions, and phosphorus removal was calculated under the same conditions as described above, and the results are shown in table 3.

TABLE 3

(Code)	Removal rate of
		CRB12	64.43％
CRB22	81.43％
		CRB32	58.89％
CRB42	27.20％
		CRB52	53.48％
CRB62	45.49％
		PL2	42.27％

As can be seen from Table 3, the advantageous effect of using the adsorbent of the present invention (CRB 22) is more pronounced when treating high-concentration phosphorus wastewater than when CRB12, CRB62 and commercial phosphorus locked agent PL2 are used, whereas the removal rate of CRB32, CRB42 and CRB52 without using the specific ratio of the present invention is even much lower than that of CRB12.

Example 3:

the solution with the phosphorus concentration of 5mg/L is prepared by adopting monopotassium phosphate, and the pH values of 5, 7, 9 and 11 are respectively adjusted by adopting 0.1mol/L HCl solution and 0.1mol/L NaOH solution. Then weighing about 100mg of the adsorbents CR B22, the commercial phosphorus-locked agents PL2, CRB42, CRB52 and CRB62 in the table 1 of the embodiment 2, respectively adding the weighed adsorbents into 200mL of phosphorus solution, setting 2 times of the adsorption, and placing the adsorbent on a shaking table; the table was set at 200rpm,24h. And finally, filtering the reaction solution by adopting a 0.45-micrometer glass fiber filter membrane, and determining the phosphorus content of the stock solution and the phosphorus content after adsorption.

As a result, as shown in FIG. 2, it was found that the pH range of the commercial P-locker PL2 was only 5 to 7, while the pH range of CRB22 was 5 to 11, which is far superior to that of the commercial P-locker PL2.

Example 4:

the 6 glass jars with length, width and height of 0.6m.0.5m.1.0 m were divided into two groups, one group was 3 control groups without any substance added, one group was 3 treatment groups with CRB22 of example 2 added (referred to as treatment groups for short), and 270L of eutrophic lake water was added to each of the 6 glass jars, and the total phosphorus content and the soluble phosphorus content in the initial water body were found to be 0.537. + -. 0.196mg/L and 0.329. + -. 0.175mg/L, respectively. Weighing 1080g of CRB22, adding the CRB22 into a glass tank of a treatment group, wherein the addition amount is 4g/L, measuring the total phosphorus and soluble phosphorus content of the water body every 2 days, the change of the total phosphorus and soluble phosphorus content of the water body is shown in figure 3, the highest removal rate of the total phosphorus content of the water body of the treatment group after 7 days is 73.33 percent, the highest removal rate of the soluble phosphorus is 99.01 percent, the lowest soluble phosphorus content of the water body can reach 0.006mg/L, and the CRB22 phosphorus removal particles prepared by the method can effectively remove the phosphorus content of the water body in field eutrophic water.

Example 5:

an organic glass packed column with the inner diameter of 8cm is adopted, the height of the CRB22 in the embodiment 2 is 20cm, the rotating speed of a peristaltic pump is set to be 50rpm, the flow rate is 220mL/min, the concentration of the phosphorus solution entering water is 100mg/L, the concentration of the phosphorus in the water is measured to be 0.217mg/L, and the removal rate is 99.78%. Therefore, the CRB22 dephosphorization particles prepared by the method have a good removal effect on high-concentration phosphorus wastewater, and can be used for sewage treatment plants.

The situation in the actual water body (including eutrophic lake water and sewage) is more complicated, the adsorbent with good removal effect under the standard experimental conditions does not necessarily have the same good effect in the actual water body treatment, and according to the records of examples 4 and 5, the CRB22 phosphorus removal particles of the present invention also show excellent phosphorus removal effect in the actual water body treatment.

The above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment, and the present invention shall fall within the protection scope of the present invention as long as the technical effects of the present invention are achieved by the same means. The technical solution and/or the embodiments thereof may be variously modified and varied within the scope of the present invention.

Claims

1. The phosphorus removal particle adsorbent is characterized by comprising the following raw materials in parts by weight: 1 part of calcium hydroxide, 6.5-8.5 parts of red soil and 0.5-2.5 parts of bentonite.

2. The phosphorus removal granular adsorbent of claim 1, wherein the raw materials comprise, by weight: 1 part of calcium hydroxide, 8 parts of red soil and 1 part of bentonite.

3. The phosphorus removal granular adsorbent of claim 1, wherein the raw materials comprise, by weight: 1 part of calcium hydroxide, 8.5 parts of red soil and 0.5 part of bentonite.

4. The phosphorus removal granular adsorbent of claim 1, wherein the raw materials comprise, by weight: 1 part of calcium hydroxide, 6.5 parts of red soil and 2.5 parts of bentonite.

5. A preparation method of the dephosphorizing granular adsorbent of any one of claims 1 to 4, comprising the following steps: mixing the raw materials and granulating.

6. The preparation method of claim 5, wherein the dephosphorizing granular adsorbent with a particle size of 1-5mm is obtained by mixing, granulating and sieving.

7. The preparation method according to claim 6, wherein the mixture is dried for 24 hours at 40-65 ℃ after being sieved, and sealed.

8. The dephosphorization particle adsorbent of any one of claims 1 to 4 is applied to the field of dephosphorization of water body.