Defluorination agent for deep defluorination and preparation method thereof

Abstract

The invention relates to the technical field of wastewater treatment, in particular to a fluorine removal agent for deep fluorine removal and a preparation method thereof, and the fluorine removal agent for deep fluorine removal comprises the following raw materials by weight: 2-5 parts of chitosan; 65-90 parts of polyaluminum chloride; 5-15 parts of magnesium oxide; 1-5 parts of titanium dioxide; 1-5 parts of manganese oxide; and 1-5 parts of lanthanum oxide. The fluorine removal agent has the beneficial effects that the obtained fluorine removal agent gets rid of the constraint of traditional calcium salt, a key catalyst (such as titanium dioxide, manganese dioxide and other transition metal oxides) is introduced through comparison and selection on the basis of controlling the compatibility material combination and synthesis reaction process, the catalyst has a catalysis function on a complex reaction, the adsorption capacity of the fluorine removal agent can be improved, and the fluorine removal effect is improved. And a micro-flocculation core growth position is provided to generate an adsorption and clamping effect. The fluorine ion content of the pretreated fluorine-containing wastewater (the fluorine ion content is 20 mg / L or below) can be reduced to 2 mg / L or below, and the fluorine ion removal rate reaches 90% or above.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a defluorinating agent for deep defluorination and a preparation method thereof. Background Art

[0002] With the rapid development of the fluorine chemical industry, the environmental pollution caused by the discharge of fluorine-containing wastewater is becoming increasingly serious. Fluorine is a double-edged sword. It is an indispensable component of the human body, animals, plants and nature, but excessive fluorine pollution caused by industrial production will also cause great harm to the human body, animals, plants and nature. Therefore, how to reduce the excessive fluorine pollution generated in the industrial production process to a level that is suitable for the survival of the human body, animals, plants and nature is the focus of scientific researchers and environmentalists in various countries.

[0003] In recent years, governments at all levels have attached increasing importance to river basin ecological management, and the emission standards for pollutants will become more stringent. Many industries related to fluorine wastewater will face the requirement to implement enterprise wastewater recycling and reuse. However, it is difficult for traditional chemical precipitation methods to treat fluorine-containing wastewater to meet the special emission standard values ​​of water pollutants, and it is also impossible to meet the industrial wastewater reuse standards. Therefore, for industries that produce a large amount of fluorine-containing wastewater, it is imperative to seek stable and reliable deep treatment technology and wastewater reuse technology.

[0004] Fluoride-containing wastewater has a wide range of sources, complex water quality, serious environmental pollution, and difficulty in treating fluoride pollutants, which limits the development of fluoride removal technology and leads to many bottlenecks. At present, flocculation sedimentation, adsorption and reverse osmosis are the most effective methods for deep treatment of fluoride-containing wastewater (to meet discharge standards or reuse effluent). However, in terms of treatment effect and economy, these methods still have many technical difficulties: (1) Increasingly stringent environmental emission requirements (fluoride-containing wastewater discharge may be subject to special emission standards, that is, fluoride concentration below 2.0 mg / L) pose greater challenges to current deep defluorination technology, and more efficient materials and more optimized technologies are urgently needed to achieve the control of fluoride pollutants.

[0005] (2) Existing defluorination adsorbents have disadvantages such as low adsorption saturation, short service life, and poor cost-effectiveness of defluorination.

[0006] Researchers have found that defluoridation agents remove fluoride ions during the deep treatment of fluoride-containing wastewater through electrostatic adsorption, complexation, chemical precipitation, hydrogen bonding, physical adsorption, and many other effects. Therefore, in the design and preparation of defluoridation agents, the fluoride removal efficiency of the product should be improved from the perspective of mechanism. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a defluorination agent for deep defluorination to achieve deep treatment of fluorine pollution and a preparation method thereof. In order to solve the above technical problems, the technical solution adopted by the present invention is: to provide a defluorination agent for deep defluorination, comprising the following raw material compositions in weight ratio: 2-5 parts of chitosan; 65-90 parts of polyaluminium chloride; 5-15 parts of magnesium oxide; 1-5 parts of titanium dioxide; 1-5 parts of manganese oxide; and 1-5 parts of lanthanum oxide.

[0008] Preferably, the above-mentioned defluorination agent for deep defluorination comprises raw materials in the following weight ratio: 2 parts of chitosan; 65 parts of polyaluminium chloride; 5 parts of magnesium oxide; 1 part of titanium dioxide; 1 part of manganese oxide; and 1 part of lanthanum oxide.

[0009] Preferably, the above-mentioned defluorination agent for deep defluorination comprises the following raw materials in the following weight ratio: 3 parts of chitosan; 70 parts of polyaluminium chloride; 10 parts of magnesium oxide; 3 parts of titanium dioxide; 3 parts of manganese oxide; and 3 parts of lanthanum oxide.

[0010] Preferably, the above-mentioned defluorination agent for deep defluorination comprises the following raw materials in the following weight ratio: 5 parts of chitosan; 90 parts of polyaluminium chloride; 15 parts of magnesium oxide; 5 parts of titanium dioxide; 5 parts of manganese oxide; and 5 parts of lanthanum oxide.

[0011] Another technical solution provided by the present invention is to provide a method for preparing the above-mentioned defluorination agent for deep defluorination, comprising the following steps: Chitosan, polyaluminium chloride, magnesium oxide, titanium dioxide, manganese oxide and lanthanum oxide are uniformly mixed in water, stirred on a magnetic stirrer for 0.5-4 hours, and then a stable colloidal structure is generated through a hydrolysis condensation reaction. The mixture is placed in a vacuum oven and dried for 12-24 hours, and then heated in a forced air oven at 80-120°C. After 8-24 hours, the mixture is taken out and ground to obtain a defluoridating agent.

[0012] Preferably, the preparation method of the above-mentioned deep defluorination defluorination agent specifically comprises the following steps: 3 g of chitosan, 70 g of polyaluminium chloride, 10 g of magnesium oxide, 3 g of titanium dioxide, 3 g of manganese oxide and 3 g of lanthanum oxide were uniformly mixed in 1000 ml of water, stirred on a magnetic stirrer for 2 hours, and then a stable colloidal structure was generated through a hydrolysis condensation reaction. The mixture was placed in a vacuum oven and dried for 14 hours, and then heated in a 100°C forced air oven. After 14 hours, the mixture was taken out and ground to obtain a defluoridating agent.

[0013] The beneficial effect of the present invention is that the defluoridation agent obtained by the present invention is free from the constraints of traditional calcium salts, and a key catalyst (such as transition metal oxides such as titanium dioxide and manganese dioxide) is introduced by comparison on the basis of controlling the compatibility of the components and the synthesis reaction process, which not only has a catalytic function for the complex reaction, but also can improve the adsorption capacity of the defluoridation agent, provide a micro-flocculation nucleus growth position to produce an adsorption and clamping effect. The fluoride ion content of the pretreated fluoride-containing wastewater (fluoride ion content below 20 mg / L) can be reduced to below 2 mg / L, and the fluoride ion removal rate can reach more than 90%. DETAILED DESCRIPTION

[0014] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation methods.

[0015] The key concept of the present invention is that in the preparation method of the defluoridation agent for deep defluoridation of the present invention, a large number of crystals are generated by rapid reaction during the hydrolysis condensation reaction, so that a microporous glandular structure is formed inside the molecule. The long-chain molecular segments in the synthesis process have a large specific surface area and a strong adsorption effect with a high Zeta potential. In the synthesis process, a large number of polyhydroxy cations are present, which have a high charge density and a medium degree of polymerization and a strong complexing ability.

[0016] Titanium dioxide, manganese oxide, lanthanum oxide and other metal oxides are also introduced in the synthesis reaction process of the defluoridating agent. The transition metal oxides have fine particles, large specific surface area, high positive charge content and large loading capacity. They not only have catalytic function for the complexation reaction of fluoride ions, but also can enhance the adsorption function of the defluoridating agent, produce adsorption encapsulation, strong electrostatic adsorption and other effects, and greatly improve the deep treatment efficiency of the defluoridating agent.

[0017] Embodiment 1 A method for preparing a defluorinating agent for deep defluorination comprises the following steps: 2 g of chitosan, 65 g of polyaluminium chloride, 5 g of magnesium oxide, 5 g of titanium dioxide, 3 g of manganese oxide and 1 g of lanthanum oxide are uniformly mixed in 800 ml of water, stirred on a magnetic stirrer for 2 hours, and then a stable colloidal structure is generated through a hydrolysis condensation reaction. The mixture is placed in a vacuum oven and dried for 14 hours, and then heated in a forced air oven at 80°C. After 14 hours, the mixture is taken out and ground to obtain a defluoridating agent.

[0018] The obtained defluoridating agent reduces the fluoride content of the pretreated fluoride-containing wastewater (fluoride ion content 19 mg / L) to below 2 mg / L, and the fluoride ion removal rate reaches more than 90%.

[0019] Embodiment 2 A method for preparing a defluorinating agent for deep defluorination comprises the following steps: 3 g of chitosan, 70 g of polyaluminium chloride, 10 g of magnesium oxide, 3 g of titanium dioxide, 3 g of manganese oxide and 3 g of lanthanum oxide were uniformly mixed in 1000 ml of water, stirred on a magnetic stirrer for 2 hours, and then a stable colloidal structure was generated through a hydrolysis condensation reaction. The mixture was placed in a vacuum oven and dried for 14 hours, and then heated in a 100°C forced air oven. After 14 hours, the mixture was taken out and ground to obtain a defluoridating agent.

[0020] The obtained defluoridating agent reduces the fluoride content of the pretreated fluoride-containing wastewater (fluoride content 18 mg / L) to below 2 mg / L, and the fluoride removal rate reaches more than 90%.

[0021] Embodiment 3 A method for preparing a defluorinating agent for deep defluorination comprises the following steps: 5 g of chitosan, 90 g of polyaluminium chloride, 15 g of magnesium oxide, 5 g of titanium dioxide, 5 g of manganese oxide and 5 g of lanthanum oxide are uniformly mixed in 1200 ml of water, stirred on a magnetic stirrer for 4 hours, and then subjected to hydrolysis and condensation reaction to form a stable colloidal structure, which is then placed in a vacuum oven and dried for 24 hours, and then heated in a 120°C forced air oven. After 24 hours, the defluoridating agent is taken out and ground.

[0022] The obtained defluoridating agent reduces the fluoride content of the pretreated fluoride-containing wastewater (fluoride ion content 20 mg / L) to below 2 mg / L, and the fluoride ion removal rate reaches more than 90%.

[0023] Embodiment 4 A method for preparing a defluorinating agent for deep defluorination comprises the following steps: 4 g of chitosan, 80 g of polyaluminium chloride, 12 g of magnesium oxide, 4 g of titanium dioxide, 4 g of manganese oxide and 4 g of lanthanum oxide were uniformly mixed in 1100 ml of water, stirred on a magnetic stirrer for 4 hours, and then subjected to hydrolysis and condensation reaction to form a stable colloidal structure. The mixture was placed in a vacuum oven and dried for 24 hours, and then heated in a 120°C forced air oven. After 24 hours, the mixture was taken out and ground to obtain a defluoridating agent.

[0024] The obtained defluoridating agent reduces the fluoride content of the pretreated fluoride-containing wastewater (fluoride ion content 20 mg / L) to below 2 mg / L, and the fluoride ion removal rate reaches more than 90%.

[0025] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A defluorinating agent for deep defluorination, characterized in that: The raw material composition comprises the following weight ratios: 2-5 parts of chitosan; 65-90 parts of polyaluminium chloride; 5-15 parts of magnesium oxide; 1-5 parts of titanium dioxide; 1-5 parts of manganese oxide; and 1-5 parts of lanthanum oxide.

2. The defluorination agent for deep defluorination according to claim 1, characterized in that: The raw material composition comprises the following weight ratios: 2 parts of chitosan; 65 parts of polyaluminium chloride; 5 parts of magnesium oxide; 1 part of titanium dioxide; 1 part of manganese oxide; and 1 part of lanthanum oxide.

3. The defluorination agent for deep defluorination according to claim 1, characterized in that: The raw material composition comprises the following weight ratios: 3 parts of chitosan; 70 parts of polyaluminium chloride; 10 parts of magnesium oxide; 3 parts of titanium dioxide; 3 parts of manganese oxide; and 3 parts of lanthanum oxide.

4. The defluorination agent for deep defluorination according to claim 1, characterized in that: The invention comprises the following raw material compositions in weight proportions: 5 parts of chitosan; 90 parts of polyaluminium chloride; 15 parts of magnesium oxide; 5 parts of titanium dioxide; 5 parts of manganese oxide; and 5 parts of lanthanum oxide.

5. A method for preparing the defluorination agent for deep defluorination according to any one of claims 1 to 4, characterized in that: The steps include: Chitosan, polyaluminium chloride, magnesium oxide, titanium dioxide, manganese oxide and lanthanum oxide are uniformly mixed in water, stirred on a magnetic stirrer for 0.5-4 hours, and then a stable colloidal structure is generated through a hydrolysis condensation reaction. The mixture is placed in a vacuum oven and dried for 12-24 hours, and then heated in a forced air oven at 80-120°C. After 8-24 hours, the mixture is taken out and ground to obtain a defluoridating agent.

6. The method for preparing a defluorinating agent for deep defluorination according to claim 5, characterized in that: The specific steps include: 3 g of chitosan, 70 g of polyaluminium chloride, 10 g of magnesium oxide, 3 g of titanium dioxide, 3 g of manganese oxide and 3 g of lanthanum oxide are uniformly mixed in 1000 ml of water, stirred on a magnetic stirrer for 2 hours, and then a stable colloidal structure is generated through a hydrolysis condensation reaction. The mixture is placed in a vacuum oven and dried for 14 hours, and then heated in a 100°C forced air oven. After 14 hours, the mixture is taken out and ground to obtain a defluoridating agent.