A high-efficiency phosphorus removal agent and its preparation method

Abstract

This invention discloses a highly efficient phosphorus removal agent, comprising, by mass percentage, 5-8% aluminum, 1.0-1.5% iron, 1‰-3‰ manganese, 0.5-1‰ boron, and 0.1%-0.5% ultrafine powder activated carbon. This phosphorus removal agent exhibits high phosphorus removal efficiency, strong stability, and a dosage that is 40-70% lower than traditional polyaluminum / iron ratios, resulting in a TP concentration of less than 0.05 mg / L in treated phosphorus-polluted water, meeting the requirements for Class II or higher surface water quality standards. Simultaneously, it reduces subsequent sludge production, saving on sludge disposal costs.

Description

Technical Field

[0001] This invention belongs to the field of water phosphorus removal technology, specifically relating to a high-efficiency phosphorus removal agent and its preparation method, which is particularly suitable for phosphorus removal in water with low phosphorus content. Background Technology

[0002] Phosphorus can cause eutrophication and cyanobacterial blooms, posing threats to human health and the ecological environment. Currently, the main methods for removing phosphorus from water include ion exchange, crystallization, chemical precipitation, biological treatment, and adsorption. Ion exchange and chemical precipitation are costly and cause serious secondary pollution; crystallization and biological treatment are difficult to operate, require time and maintenance, and have limited practical applications. In contrast, adsorption is simple to operate, inexpensive, and environmentally friendly. Commonly used adsorbents are iron (hydrogen) oxides and aluminum (hydrogen) oxides with strong adsorption capacity. However, existing aluminum / iron adsorbents have slow adsorption rates, small capacities, low stability, and limited adsorption capacity for trace amounts of phosphorus.

[0003] Studies have shown that a total phosphorus concentration (TP) of less than 0.05 mg / L entering the receiving water body can effectively control eutrophication. Currently, most wastewater treatment plants in China discharge effluent in accordance with the national Class A standard, which is higher than the Class III requirement for river surface water (TP ≤ 0.2 mg / L) and far exceeds the Class III requirement for lake and reservoir surface water (TP ≤ 0.05 mg / L). However, traditional coagulation sedimentation and flotation methods using iron / aluminum salt coagulants have low phosphorus removal efficiency and low stability, making it difficult to achieve a TP ≤ 0.2 mg / L phosphorus content in the treated water. Furthermore, increasing the dosage of iron / aluminum salt coagulants can lead to increased slag production and secondary pollution. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-efficiency phosphorus removal agent with high phosphorus removal efficiency, strong stability and low cost, as well as its preparation method.

[0005] The technical solution adopted in this invention is as follows:

[0006] A highly efficient phosphorus removal agent, by mass percentage, comprises 5-8% aluminum, 1.0-1.5% iron, 1‰-3‰ manganese, 0.5-1‰ boron, and 0.1%-0.5% ultrafine powder activated carbon.

[0007] Furthermore, the ultrafine powder activated carbon is obtained by carbonization, activation, and grinding of coconut shell charcoal, high-temperature bamboo charcoal, or wood charcoal.

[0008] Furthermore, the particle size of the ultrafine powder activated carbon is 2μm-10μm.

[0009] A method for preparing a highly efficient phosphorus removal agent includes the following steps:

[0010] S1. Prepare ultrafine powder activated carbon: Carbonize, activate, and grind coconut shell charcoal, high-temperature bamboo charcoal, or wood charcoal to produce ultrafine powder activated carbon with a particle size of 2μm-10μm.

[0011] S2. Polymerization reaction: Preheat hydrochloric acid to 50-70℃, slowly add activated alumina and mix for 2 hours, then add ferric chloride and manganese chloride and continue the reaction for 2-3 hours. After the reaction is completed, let it stand and cool.

[0012] S3. Compounding: Stir the ultrafine powder activated carbon from step S1 with the polymerization product from step S2 until homogeneous.

[0013] S4. Adjust the degree of polymerization: Add boric acid to the product from step S3 and stir until homogeneous;

[0014] S5. Static aging: The product from step S4 is aged at room temperature for 20-30 hours to obtain a highly efficient phosphorus removal agent.

[0015] Furthermore, the highly efficient phosphorus removal agent is added to phosphorus-containing water bodies for phosphorus removal.

[0016] Furthermore, the removal capacity of the highly efficient phosphorus removal agent is 15.6-26.0 mg / g.

[0017] The beneficial effects of this invention are:

[0018] 1. The phosphorus removal agent of this invention is low in cost and simple in preparation method. In phosphorus-polluted water, the proton dissociation in water molecules causes hydroxylation of the manganese surface. The manganese surface charge becomes positive or negative due to the protonation or deprotonation of the hydroxyl groups. Free phosphorus in the water generates negatively charged ions such as H2PO-4, HPO2-4, and PO3-4, which can quickly react with Al3+ or Fe3+ metal ions to form insoluble phosphate precipitates. The hydroxylation of the manganese surface improves the phosphorus removal efficiency and removal speed. Even when the phosphorus content in the water is trace, it can be quickly precipitated due to the charge effect.

[0019] 2. The present invention produces ultrafine powder activated carbon with a particle size of 2μm to 10μm by carbonization, activation and grinding of coconut shell charcoal, high-temperature bamboo charcoal or wood charcoal. It has high active sites and specific surface area and rich pore structure. It removes phosphorus from slightly polluted water (TP < 0.1mg / L) through adsorption and catalysis. The effluent TP after removal is < 0.05mg / L.

[0020] 3. In this invention, the boric acid in the phosphorus removal agent forms a complex such as [Fe(HBO3)2]- with free Fe3+, avoiding the hydrolysis of free iron to produce hydroxide precipitation, thus improving the stability of the phosphorus removal agent. The dosage is 40-70% of that of traditional polyaluminum / iron, reducing the amount of sludge produced in the later stage and saving sludge disposal costs. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0022] The invention will now be further described in conjunction with the accompanying drawings and embodiments. Example 1

[0023] A highly efficient phosphorus removal agent, taking the preparation of 1.0 kg as an example, is prepared according to the following ratio and method (by mass percentage):

[0024] S1. Prepare ultrafine coconut shell powder activated carbon with a particle size of 2μm to 10μm. The ultrafine coconut shell powder activated carbon is commercially available.

[0025] S2. Polymerization reaction: Preheat 0.602 kg of hydrochloric acid to 50°C, slowly add 0.174 kg of activated alumina and mix for 2 hours. Add 0.043 kg of ferric chloride and 0.09 kg of manganese chloride respectively and continue the reaction for 2 hours. After the reaction is completed, let it stand and cool.

[0026] S3, Compounding: Mix 5 g of ultrafine coconut shell powder activated carbon with a particle size of 2μm ~10μm with the polymerization reaction product of step S2 until homogeneous;

[0027] S4. Adjust the degree of polymerization: Add 6g of boric acid to the product from step S3 and stir until homogeneous;

[0028] S5. Static aging: The product from step S4 is aged at room temperature for 20 hours to obtain a highly efficient phosphorus removal agent.

[0029] Take 1L of phosphorus-containing water (TP 0.78mg / L) and add 0.03g of the above-mentioned high-efficiency phosphorus removal agent for coagulation and sedimentation. Example 2

[0030] A highly efficient phosphorus removal agent, taking the preparation of 1.0 kg as an example, is prepared according to the following ratio and method (by mass percentage):

[0031] S1. Prepare high-temperature bamboo charcoal activated carbon with a particle size of 2μm to 10μm. The high-temperature bamboo charcoal activated carbon can be purchased commercially.

[0032] S2. Polymerization reaction: Preheat 0.829 kg of hydrochloric acid to 50°C, slowly add 0.109 kg of activated alumina and mix for 2 hours. Add 0.028 kg of ferric chloride and 0.03 kg of manganese chloride respectively and continue the reaction for 2 hours. After the reaction is completed, let it stand and cool.

[0033] S3, Compounding: Weigh 1g of high-temperature bamboo charcoal activated carbon with a particle size of 2μm ~ 10μm and stir it evenly with the polymerization reaction product of step S2.

[0034] S4. Adjust the degree of polymerization: Add 3g of boric acid to the product from step S3 and stir until homogeneous;

[0035] S5. Static aging: The product from step S4 is aged at room temperature for 20-30 hours to obtain a highly efficient phosphorus removal agent.

[0036] Take 1L of phosphorus-containing water (TP 0.78mg / L) and add 0.03g of the above-mentioned high-efficiency phosphorus removal agent for coagulation and sedimentation. Example 3

[0037] A highly efficient phosphorus removal agent, taking the preparation of 1.0 kg as an example, is prepared according to the following ratio and method (by mass percentage):

[0038] S1. Prepare activated carbon with a particle size of 2μm to 10μm, which can be purchased commercially;

[0039] S2. Polymerization reaction: Preheat 0.726 kg of hydrochloric acid to 50°C, slowly add 0.130 kg of activated alumina and mix for 2 hours. Add 0.043 kg of ferric chloride and 0.09 kg of manganese chloride respectively and continue the reaction for 2 hours. After the reaction is completed, let it stand and cool.

[0040] S3, Compounding: Weigh 5g of commercially available activated charcoal with a particle size of 2μm ~ 10μm and mix it evenly with the polymerization reaction product of step S2;

[0041] S4. Adjust the degree of polymerization: Add 6g of boric acid to the product from step S3 and stir until homogeneous;

[0042] S5. Static aging: The product from step S4 is aged at room temperature for 30 hours to obtain a highly efficient phosphorus removal agent.

[0043] Take 1L of phosphorus-containing water (TP 0.78mg / L) and add 0.05g of the above-mentioned high-efficiency phosphorus removal agent for coagulation and sedimentation. Example 4

[0044] A highly efficient phosphorus removal agent, taking the preparation of 1.0 kg as an example, is prepared according to the following ratio and method (by mass percentage):

[0045] S1. Prepare ultrafine coconut shell powder activated carbon with a particle size of 2μm to 10μm. The ultrafine coconut shell powder activated carbon is commercially available.

[0046] S2. Polymerization reaction: Preheat 0.764 kg of hydrochloric acid to 50°C, slowly add 0.174 kg of activated alumina and mix for 2 hours. Add 0.028 kg of ferric chloride and 0.03 kg of manganese chloride respectively and continue the reaction for 2 hours. After the reaction is completed, let it stand and cool.

[0047] S3, Compounding: Mix 1g of ultrafine coconut shell powder activated carbon with a particle size of 2μm ~ 10μm with the polymerization product of step S2 until homogeneous;

[0048] S4. Adjust the degree of polymerization: Add 3g of boric acid to the product from step S3 and stir until homogeneous;

[0049] S5. Static aging: The product from step S4 is aged at room temperature for 25 hours to obtain a highly efficient phosphorus removal agent.

[0050] Take 1L of phosphorus-containing water (TP 0.78mg / L) and add 0.05g of the above-mentioned high-efficiency phosphorus removal agent for coagulation and sedimentation.

[0051] Comparative Example 1

[0052] The difference from Example 1 is that the phosphorus removal agent does not contain manganese, but all other aspects are the same as in Example 1.

[0053] Comparative Example 2

[0054] The difference from Example 1 is that the phosphorus removal agent does not contain boron, but all other aspects are the same as in Example 1.

[0055] Table 1 shows the phosphorus content and phosphorus removal rate of the effluent from phosphorus-containing water bodies after treatment in Examples 1-4 and Comparative Examples 1-2.

[0056] Table 1. Phosphorus content and phosphorus removal rate of effluent from phosphorus-containing water bodies treated in Examples 1-4 and Comparative Examples 1-2

[0057]

[0058] The phosphorus removal agent of this invention has high phosphorus removal efficiency, strong stability, and a dosage that is 40-70% of that of traditional polyaluminum / iron. It is low-cost and can treat phosphorus-polluted water bodies with TP levels of less than 0.05 mg / L, meeting the requirements of Class II or above surface water quality indicators, and reducing the amount of slag generated in the later stage by more than 10%.

[0059] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a phosphorus removal agent, characterized in that, Includes the following steps: S1. Prepare particles with a diameter of 2μm. ~ 10μm of Charcoal and activated carbon; S2. Polymerization reaction: Preheat 0.726 kg of hydrochloric acid to 50°C, slowly add 0.130 kg of activated alumina and mix for 2 hours. Then add 0.043 kg of ferric chloride and 0.09 kg of manganese chloride and continue the reaction for 2 hours. After the reaction is completed, let it stand and cool. S3, Compound: Weigh 5g of particles with a diameter of 2μm ~ The 10μm charcoal activated carbon was mixed evenly with the polymerization product of step S2. S4. Adjust the degree of polymerization: Add 6g of boric acid to the product from step S3 and stir until homogeneous; S5. Static aging: The product from step S4 is aged at room temperature for 30 hours to obtain 1.0 kg of phosphorus removal agent.

2. The application of the phosphorus removal agent obtained by the preparation method according to claim 1 in the treatment of phosphorus-containing water bodies.

Images