CN106006814A - Sediment/zeolite nitrogen control material prepared from lake sediment, method and application thereof - Google Patents

Abstract

The invention relates to a sediment/zeolite nitrogen control material prepared by using lake bottom mud and its method and application. The lake bottom mud is collected as a raw material, freeze-dried, ground and sieved to obtain a sediment powder for standby use; the zeolite is taken and ground Sieve to get the zeolite powder and set it aside; then take the treated sediment powder and heat it at a constant temperature, then cool it and set it aside; add the zeolite powder to the sediment powder in proportion, mix it evenly, and then add it to the mixed raw material Add water to infiltrate, extrude, and roast to obtain sediment/zeolite nitrogen-controlling materials; the present invention uses lake sediment as raw material and combines zeolite materials, so that the sediment/zeolite nitrogen-controlling materials have significantly improved ammonia nitrogen adsorption performance and ammonia nitrogen desorption capacity Significantly reduced; materials are cheap, high safety, good social and economic benefits, no ecological risk to the lake water body, energy saving and environmental protection; during the application process, the ammonia nitrogen concentration in the interstitial water of the sediment is significantly reduced, and the purpose of preventing and controlling the release of ammonia nitrogen from the lake bottom sediment is achieved.

Description

Sediment/zeolite nitrogen control material prepared from lake bottom mud and its method and application

technical field

The invention belongs to the technical field of lake bottom mud pollution control, and in particular relates to a sediment/zeolite nitrogen control material prepared by using lake bottom mud, a method and an application.

Background technique

Ammonia nitrogen is an important pollutant in water bodies, mainly from various industrial wastewater and urban domestic wastewater. Excessive ammonia nitrogen content in the water body can cause eutrophication of the water body, have a toxic effect on aquatic organisms, cause black and odorous water bodies, deteriorate the quality of the water environment, increase the difficulty and cost of water supply treatment, and thus affect human health. Sediment, also known as bottom mud, is an important destination and reservoir for pollutants entering rivers, lakes and other surface water bodies, and is also the internal source of overlying water pollution. Especially when exogenous pollution is effectively controlled or completely cut off, sediments will become an important source of water pollutants on surface water bodies. Since nitrogen released from sediments, especially ammonia nitrogen, is an important source of water nitrogen overlying eutrophic lakes, it is particularly important to control the release of ammonia nitrogen from sediments in eutrophic shallow lakes.

At present, the treatment methods of ammonia nitrogen wastewater mainly include stripping method, breakpoint chlorination method, ion exchange method and other traditional treatment methods, but there are few studies on the release control of ammonia nitrogen at the sediment-water interface of eutrophic lakes. The existing treatment technologies for eutrophic shallow lake sediments are mainly divided into two types: in-situ treatment technology and ex-situ treatment technology. Ex-situ treatment is mainly sediment dredging; in-situ treatment can be divided into physical, chemical and biological treatment techniques. Among them, physical treatment technologies mainly include in-situ covering and artificial aeration; chemical treatment technologies mainly include chemical passivation technology and chemical oxygenation; biological treatment technologies mainly include animal and plant, microorganism and ecological restoration treatment technologies. Ex-situ treatment is to excavate polluted sediments and send them to other places for treatment. Ex-situ treatment is mainly an environmental protection dredging technology. However, when the measures taken in the dredging project are improper, it will bring serious consequences, such as improper control of dredging depth, Deep pollutants will be released into the water body, breaking the original nitrogen and phosphorus dissolution balance, causing the sediment to be released for a long time after dredging. At the same time, the dredging process will affect the original aquatic ecosystem in the lake water environment and destroy the living environment of benthic organisms. , affecting the restoration of the lake ecosystem, and dredging requires high funds, and the cost of treatment is very expensive. Among the in-situ treatment technologies, in-situ covering technology, also known as sealing and masking technology, is a method of placing a layer of clean covering on the surface of polluted sediments to prevent the release of sediment pollutants to water bodies. However, it also has many shortcomings:

(1) Covering materials need a large amount of clean sediment and other materials, and the source is difficult;

(2) It is difficult to guarantee its uniformity when covering, and adding it will increase the thickness of the bottom mud and reduce the depth of the water body;

(3) In waters with fast water flow, covering materials are easily eroded, and covering technology is also destructive to benthic ecosystems.

Among the in-situ treatment techniques, the chemical treatment technique fixes the pollutants in the sediment by using chemical reagents. However, the use of chemical reagents will have the problem of poor chemical ecological safety, which will have a great impact on the organisms in the water body, which is difficult for the public to accept, and will easily cause secondary pollution of the water body.

Among in-situ treatment technologies, biological treatment technology uses organisms to degrade sediments and pollutants by adding plants, animals, and microorganisms, and eliminate or reduce their toxicity. In recent years, researchers at home and abroad have artificially constructed simulated ecosystems (such as artificial floating islands, artificial wetlands, etc.), the restoration of microorganisms, plants, and animals is unified to form a regional bioremediation technology, which is applied to engineering practice and has achieved good environmental, ecological and economic benefits. Benefits, however, ecological restoration technology cycle is long, the short-term effect is not obvious. Since the lake sediment-water interface is a complex environment, if its environmental conditions change slightly, the risk of releasing nutrients such as nitrogen and phosphorus will be great. In response to this problem, adsorption technology has been tried to control the release of ammonia nitrogen at the sediment-water interface of eutrophic shallow lakes in the world, because the adsorption technology has the advantages of simple operation, fast and efficient, no secondary pollution, and the adsorbent can be reused.

At present, the main sediment-water interface ammonia nitrogen adsorption materials at home and abroad are: activated biochar, apatite, organoclay, natural and modified zeolite and calcite, etc. Among them, zeolite shows good ammonia nitrogen adsorption performance due to its large specific surface area and cation exchange capacity. For example, in the in-situ remediation method disclosed in the Chinese patent document CN102674646, a surface water body polluted sediment, by injecting nitrate into the sediment, using nitrate to remove organic pollutants in the sediment, inhibiting the release of phosphorus, and then covering the active The material is added to the bottom mud-water interface to form an active covering layer system. The active covering material includes natural zeolite or cationic surfactant modified zeolite, and the active covering layer system is used to control the ammonia nitrogen released from the bottom mud. And prevent the migration of nitrate in the pore water to the overlying water and prevent the pollution of nitrate in the overlying water. Through the above scheme, the in-situ restoration of the bottom sediment of surface water bodies such as lakes and rivers can be realized, and the release of organic matter such as nitrogen and phosphorus in the bottom sediment can be controlled. However, the above scheme still has many disadvantages as follows: 1. The modified zeolite needs to use a cationic surfactant in the modification process. Because the price of the cationic surfactant is relatively high, it greatly increases the pollution of the surface water body by using the modified zeolite. 2. The zeolite needs to be cleaned with distilled water after the cationic surfactant is mixed and modified. When the cleaning is not thorough, part of the cationic surfactant may be temporarily stored in the pore cavity of the zeolite. When the modified zeolite When used for in-situ remediation of surface water bodies, the cationic surfactants not adsorbed in the zeolite will be released into the overlying water body, causing secondary pollution of the water body; 3. Since the chemical reagent nitrate is used in the in-situ method, In order to reduce the proportion of nitrate nitrogen entering the overlying water, modified zeolite or a mixture of modified zeolite and natural zeolite wrapped in geotextiles was added to the bottom mud-water interface, but even if the nitrate nitrogen was reduced The proportion of nitrogen entering the overlying water is still unavoidable for nitrate to enter the overlying water, causing water pollution and poor ecological security. Moreover, it is cumbersome to use modified zeolite wrapped in geotextiles to cover the sediment. 4. In this in-situ repair method, the main function of adding nitrate to the sediment is to degrade and remove organic pollutants and inhibit the migration of phosphorus in the sediment. The adsorption of ammonia nitrogen and controlled release mainly rely on modified zeolite or a mixture of modified zeolite and natural zeolite. However, the amount of ammonia nitrogen adsorption of modified zeolite and natural zeolite is limited. The use amount of the mixture of zeolite and natural zeolite greatly increases the cost. It can be seen from the above that in the field of ammonia nitrogen control at the sediment-water interface, no suitable, cheap, green and ecologically safe ammonia nitrogen adsorption and controlled release materials have been found. How to find a suitable ammonia nitrogen adsorption and controlled release material to change the micro-environment of the sediment-water interface, thereby controlling the endogenous pollution load of the sediment, so as to facilitate the later ecological restoration of the water body is a research focus.

In "Analysis of Nitrogen and Phosphorus Adsorption/Desorption Characteristics of Taihu Lake Sediments" (Jiang Xia, Wang Qiujuan, Wang Shuhang, etc., Environmental Science, 2011, (05), 1285-1291), the average adsorption amount of ammonia nitrogen in Taihu Lake sediments is 23.55mg/kg , the adsorption capacity is larger in heavily polluted areas. It can be seen that lake sediments have a certain adsorption capacity for ammonia nitrogen. However, since lake sediments are affected by various environmental factors, there is a process of source-sink conversion of nutrient elements with seasonal changes. For details, please refer to "Taihu Lake Sediment-Water Interface Biogenic Elements Migration Mechanism and Quantification—1. Ammonium The spatial difference of the release rate of nitrogen and the source-sink flux" (Fan Chengxin, Zhang Lu, Qin Boqiang et al., Lake Science, 2004, (01), 10-20). Due to the difficulty in controlling the source-sink conversion process of sediments, there are risks in using sediments as ammonia nitrogen adsorption and controlled release materials, which will easily aggravate the pollution of water bodies, cause secondary pollution of water bodies, and poor ecological security. There are not many reports on the preparation of ammonia nitrogen adsorbents. For example, in the prior art, the adsorbent prepared from sediments is not used for the adsorption and controlled release of ammonia nitrogen in wastewater, but for the adsorption of heavy metal ions in wastewater. A Chinese patent document CN104437374A discloses a method using Dianchi The method and application of preparing the adsorbent from the bottom mud, soaking the bottom mud with distilled water, repeat soaking, washing and drying, adding chemical reagents such as glutaraldehyde activator, and then acidifying, carbonizing, washing and drying the obtained adsorbent, Utilizing the advantages of strong adsorption performance of the sediment, low cost, energy saving and environmental protection, etc., the cost is greatly reduced, and a significant adsorption effect is obtained. However, the adsorbent prepared from sediment in the above scheme is only used to adsorb heavy metal ions, and it is not mentioned that the adsorbent can adsorb and control ammonia nitrogen in eutrophic lakes or rivers. It can be seen that even if the adsorbent prepared by sediment Adsorbents have the advantages of low cost, strong adsorption performance, energy saving and environmental protection. However, due to the high risk of preparing ammonia nitrogen adsorption and controlled release materials from sediments, there is no ammonia nitrogen control material prepared from sediments in the prior art. For this reason, the present invention provides a sediment/zeolite nitrogen control material prepared by using lake bottom mud and its method and application, so as to achieve the purpose of "treating waste with waste", reduce costs, and the prepared nitrogen control material has high safety. The adsorption and control effect of ammonia nitrogen is excellent, and there is no ecological risk to the lake water body.

Contents of the invention

The technical problem to be solved by the present invention is that the ammonia nitrogen controlled-release materials in the prior art are not strong in the adsorption of ammonia nitrogen, especially the application effect in the sediment-water interface nitrogen release resistance control is not obvious, and the cost is high and the ecological security is poor. Low benefit, and then provide a sediment/zeolite controller prepared from lake bottom mud with stronger adsorption capacity for ammonia nitrogen, especially better effect of resistance and control of ammonia nitrogen release at the sediment-water interface, and low cost, green environmental protection and high ecological security. Nitrogen materials and methods, applications.

For this reason, a kind of method that utilizes lake sediment to prepare sediment/zeolite nitrogen control material provided by the invention comprises the steps:

(1) Collect lake bottom mud, freeze-dry, grind and sieve to obtain sediment powder, for subsequent use;

(2) Get zeolite, grind and sieve to obtain zeolite powder, and set aside;

(3) Get the sediment powder obtained in step (1) and carry out constant temperature heat treatment, then cool down and set aside;

(4) Add the zeolite powder obtained in step (2) in proportion to the sediment powder processed in step (3), mix evenly, and set aside;

(5) Add water to the raw materials mixed in step (4) to infiltrate, extrude, and then roast to obtain the sediment/zeolite nitrogen-controlling material.

In the step (4), the zeolite powder accounts for 10-90% of the total mass of the mixed raw materials.

Preferably, in the step (4), the zeolite powder accounts for 40-70% of the total mass of the mixed raw materials.

More preferably, the zeolite powder accounts for 40% of the total mass of the mixed raw materials.

In the step (3), the temperature of the constant temperature heating is 100-800°C.

Preferably, in the step (3), the temperature of the constant temperature heating is 400-600°C.

More preferably, the temperature of the constant temperature heating is 600°C.

In the step (3), the time for the constant temperature heat treatment is 1-3 hours. Preferably, the heat treatment time is 3 hours.

In the step (5), the temperature at which the mixed raw materials are roasted is 500-700° C., and the roasting time is 1-3 hours.

Preferably, the temperature at which the mixed raw materials are roasted is 600° C., and the roasting time is 2 hours.

In the step (1), the lake sediment is ground through a 50-150 mesh sieve. Preferably, the lake sediment is ground through a 100-mesh sieve.

In the step (2), the zeolite is ground through a 50-150 mesh sieve. Preferably, the zeolite is ground through a 100-mesh sieve.

In the step (5), the shape of the sediment/zeolite nitrogen-controlling material is spherical, flake, massive or porous. Preferably, the sediment/zeolite nitrogen-controlling material is spherical in shape with a diameter of 3-10 mm.

The amount of water added is 10%-50% of the weight of the mixed raw materials, preferably, the amount of water added is 10%-15% of the weight of the mixed raw materials.

The lake bottom mud includes SiO ₂ , Al ₂ 0 ₃ , Fe ₂ O ₃ , CaO, MgO, K ₂ O and/or TiO ₂ components.

Preferably, the content of SiO ₂ in the lake bottom mud is 20-25%, the content of Al ₂ O ₃ is 40-50%, the content of Fe ₂ O ₃ is 20-25%, the content of CaO is 3-8%, and the content of MgO _The content is 1-4%, the K2O content is 0.1-1%, and the _TiO2 content is 1-3%.

More preferably, the content of SiO ₂ in the lake bottom mud is 22.92%, the content of Al ₂ O ₃ is 44.56%, the content of Fe ₂ O ₃ is 22.01%, the content of CaO is 5.13%, the content of MgO is 2.81%, and the content of K ₂ The O content is 0.46%, and the _TiO2 content is 2.11%.

The loss on ignition of the lake sediment is 28-32%. Preferably, the loss on ignition of the lake sediment is 30.43%.

Preferably, the lake sediment is Dianchi Lake sediment.

The present invention also provides an application of the sediment/zeolite nitrogen-controlling material prepared by the method in the field of preparing ammonia nitrogen adsorption material. The ammonia nitrogen adsorption material is a lake sediment ammonia nitrogen release resistance control material.

The above technical solution of the present invention has the following advantages compared with the prior art:

(1) A method of utilizing lake bottom mud to prepare sediment/zeolite nitrogen-controlling material according to the present invention, by collecting lake bottom mud as raw material, freeze-drying, grinding and sieving to obtain sediment powder, for subsequent use; Zeolite, ground and sieved to obtain zeolite powder, set aside; then take the processed sediment powder and carry out constant temperature heat treatment, cooling; mix zeolite powder into the sediment in proportion, mix evenly; then mix The final raw material is soaked with water, extruded, and then roasted to obtain the sediment/zeolite nitrogen-controlling material; by using lake bottom mud as raw material, heat treatment, and then adding zeolite material therein, through the deposition after heat treatment The sediment/zeolite nitrogen control material prepared by infiltration, extrusion molding and roasting has a significant effect on the adsorption of ammonia nitrogen in the interstitial water of eutrophic lake or river sediments, making the sediment adsorb ammonia nitrogen. Combined with the adsorption performance of zeolite for ammonia nitrogen, the adsorption of ammonia nitrogen is greatly improved, and unexpected effects are obtained, and the sediment/zeolite nitrogen control material is highly safe, and there is no ecological risk to the lake water body , to achieve the purpose of "using waste to treat waste", energy saving and environmental protection, and due to the addition of sediment, the amount of zeolite used is reduced, and the cost is greatly reduced. Therefore, the ammonia nitrogen adsorption capacity of the ammonia nitrogen controlled release material in the prior art is solved. strong, high cost and poor ecological security;

(2) A method of utilizing lake bottom mud to prepare sediment/zeolite nitrogen-controlling material according to the present invention optimizes the nitrogen-controlling material by controlling the mass percentage of zeolite in the nitrogen-controlling material to be 10-90%. Nitrogen material specific surface area, total pore volume, and CEC content, thereby improving the ammonia nitrogen adsorption performance of the nitrogen control material, reducing the ammonia nitrogen adsorption-desorption equilibrium concentration of the material itself, and then achieving the inhibition and control of the release of ammonia nitrogen from the lake sediment;

(3) A method of utilizing lake bottom mud to prepare sediment/zeolite nitrogen-controlling materials according to the present invention, by further adjusting the mass percentage of zeolite in the nitrogen-controlling materials to 30%-50%, both can ensure The specific surface area, total pore volume, and CEC content of the nitrogen-controlling material, and avoid excessive sediment content, block the zeolite pores and cavities, inhibit the cation exchange capacity of the zeolite, and also reduce the zeolite from static to a certain extent. Part of the adsorption capacity produced by electricity and dispersion force, the prepared nitrogen control material has the largest adsorption capacity for ammonia nitrogen in wastewater;

(4) A method of utilizing lake sediment to prepare sediment/zeolite nitrogen-controlling material according to the present invention, by controlling the heat treatment temperature of the sediment powder to be 100-800°C, the adsorption capacity of the sediment to ammonia nitrogen is increased , which reduces the adsorption-desorption equilibrium concentration of the sediment;

(5) In the method for preparing sediment/zeolite nitrogen-controlling materials by using lake bottom mud according to the present invention, by further adjusting the heat treatment temperature of the sediment powder to 400-600°C, not only significantly improve the prepared The adsorption capacity of the nitrogen-controlling material to ammonia nitrogen reduces the adsorption-desorption equilibrium concentration of the material itself, and also avoids that the internal structure of the nitrogen-controlling material may be damaged due to excessive temperature, which affects the nitrogen-controlling material's ability to absorb ammonia nitrogen. Adsorption performance, and by controlling the temperature of the heat treatment of the sediment, the service life of the sediment/zeolite nitrogen-controlling material is extended, and it can be used for a long time, and still maintains a good effect of preventing and controlling the release of ammonia nitrogen;

(6) A kind of method that utilizes lake bottom mud to prepare sediment/zeolite nitrogen-controlling material of the present invention, by controlling the time of heat treatment is 1-3 hour, has guaranteed that the nitrogen-controlling material that prepares is large to the adsorption capacity of ammonia nitrogen , the desorption amount is the smallest;

(7) A method for preparing sediment/zeolite nitrogen-controlling materials using lake bottom mud according to the present invention, by adding water to the raw materials mixed in step (4) to infiltrate and shape, and then roasting at high temperature, so that the prepared The adsorption capacity of nitrogen control materials for ammonia nitrogen is further improved, and the impurities inside the materials are removed by roasting to increase the specific surface area, especially the zeolite in the mixed raw materials, so that the adsorption capacity of nitrogen control materials for ammonia nitrogen is further improved;

(8) A method of utilizing lake bottom mud to prepare sediment/zeolite nitrogen-controlling materials according to the present invention, by controlling the roasting temperature of the mixed raw materials in the step (5) to be 500-700° C. , which not only significantly increases the adsorption capacity of the prepared nitrogen-controlling material to ammonia nitrogen, but also reduces the adsorption-desorption equilibrium concentration of the material itself, and by controlling the temperature at which the raw material mixed with the sediment and zeolite is roasted, the sediment/zeolite The service life of the zeolite nitrogen control material is extended, it can be used for a long time, and still maintains a good effect of preventing and controlling the release of ammonia nitrogen;

(9) A method of utilizing lake bottom mud to prepare sediment/zeolite nitrogen-controlling material according to the present invention, the shape of described sediment/zeolite nitrogen-controlling material is spherical, flaky or porous, which is more conducive to the Describe the adsorption of nitrogen control materials to ammonia nitrogen;

(10) A kind of sediment/zeolite nitrogen-controlling material prepared by using lake bottom mud according to the present invention has remarkable adsorption performance to ammonia nitrogen, and the amount of ammonia-nitrogen desorption of the nitrogen-controlling material is small, so that it can be widely used in In the field of preparation of ammonia nitrogen adsorption materials, it can be effectively applied in the field of prevention and control of ammonia nitrogen release at the lake sediment-water interface, and has high application and promotion value in the treatment of lake polluted sediment and the prevention and control of eutrophication.

Description of drawings

In order to make the content of the present invention more easily understood, the present invention will be described in further detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

Fig. 1 is the described sediment/zeolite nitrogen control material of different proportioning in the experimental example of the present invention to the adsorption isotherm diagram of low concentration ammonia nitrogen;

Fig. 2 is the high-concentration ammonia nitrogen adsorption isotherm diagram of the described sediment/zeolite nitrogen-controlling material of different proportions in the experimental example of the present invention;

Fig. 3 is the adsorption isotherm diagram of the described sediment/zeolite nitrogen-controlling material of different proportions in the experimental example of the present invention;

Fig. 4 is a diagram showing the removal effect of the sediment/zeolite nitrogen-controlling material in different proportions on the removal of ammonia nitrogen in sediment interstitial water in the experimental example of the present invention.

detailed description

The lake sediment used in the following Examples 3-9 was collected from the surface layer (0-15cm) in the heavily polluted area (24.908056oN; 102.690278oE) in the northeast of Dianchi Lake in May 2014.

Described zeolite is purchased from Dutch natural zeolite;

The muffle furnace was purchased from Nabertherm, Germany, model: L5/11/P330+.

Example 1

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) Collect lake bottom mud as raw material, freeze-dry, and grind through a 20-mesh sieve to obtain sediment powder for later use; wherein, the content of Al ₂ O ₃ in the lake bottom mud is 30%, Fe ₂ O ₃ The content of CaO is 10%, the content of CaO is 20%, the content of MgO is 8%, the content of K ₂ O is 1%, and the others are 31%; the loss on ignition of the lake bottom mud is 30.43%;

(2) get zeolite, grind through 200 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Put the sediment powder processed in step (1) into a muffle furnace for constant temperature heating treatment, the heating temperature is 50°C, heat for 0.5 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 95% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw material mixed in step (4), the amount of water added is 5% of the weight of the raw material mixed, extruded into blocks, and then roasted, the temperature of the roasted is 450 °C, the calcination time is 3.5 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 2

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) Collect lake bottom mud as raw material, freeze-dry, and grind through a ₂₀₀ -mesh sieve to obtain sediment powder for subsequent use; wherein, the _SiO2 content in the lake bottom mud is 30%, and the _Al2O3 content is 30%, _Fe2O3 content is ₃₀ %, CaO content is 1%, others are 9%; the loss on ignition of the lake bottom mud is 30.8%;

(2) get zeolite, grind through 20 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Place the sediment powder processed in step (1) in a muffle furnace for constant temperature heating treatment, the heating temperature is 900°C, heat for 3.5 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder processed in step (3), the zeolite accounts for 8% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw material mixed in step (4), the amount of water added is 60% of the weight of the raw material mixed, extruded into flakes, and then roasted, the temperature of the roasted is 750 °C, the calcination time is 0.5 h, and the sediment/zeolite nitrogen-controlling material is obtained.

Example 3

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) collecting lake bottom mud as raw material, freeze-drying, and grinding through a 50-mesh sieve to obtain sediment powder for subsequent use;

(2) get zeolite, grind through 150 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Place the sediment powder processed in step (1) in a muffle furnace for constant temperature heating treatment, the heating temperature is 100°C, heat for 1 hour, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the Dianchi Lake sediment after the treatment in step (3), the zeolite accounts for 90% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw materials mixed in step (4), the amount of water added is 10% of the weight of the raw materials mixed, extruded into a spherical shape with a diameter of 2 mm, and then roasted, the roasted The temperature is 500° C., and the calcination time is 3 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 4

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) collecting lake bottom mud as raw material, freeze-drying, and grinding through a 150-mesh sieve to obtain sediment powder for subsequent use;

(2) get zeolite, grind through 50 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Put the sediment powder processed in step (1) into a muffle furnace for constant temperature heating treatment, the heating temperature is 800°C, heat for 3 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 80% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw materials mixed in step (4), the amount of water added is 50% of the weight of the raw materials mixed, extruded into a spherical shape with a diameter of 12mm, and then roasted, the roasted The temperature is 700° C., and the calcination time is 1 hour to obtain the sediment/zeolite nitrogen-controlling material.

Example 5

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) collecting lake bottom mud as raw material, freeze-drying, and grinding through a 100-mesh sieve to obtain sediment powder for subsequent use;

(2) get zeolite, grind through 100 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Place the sediment powder processed in step (1) in a muffle furnace for constant temperature heating treatment, the heating temperature is 400°C, heat for 2 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 70% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw materials mixed in step (4), the amount of water added is 30% of the weight of the raw materials mixed, extruded into a spherical shape with a diameter of 3mm, and then roasted, the roasted The temperature is 550° C., and the calcination time is 2.5 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 6

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) collecting lake bottom mud as raw material, freeze-drying, and grinding through an 80-mesh sieve to obtain sediment powder for subsequent use;

(2) get zeolite, grind through 120 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Place the sediment powder processed in step (1) in a muffle furnace for constant temperature heating treatment, the heating temperature is 500°C, heat for 2.5 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 60% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to the raw materials mixed in step (4) to infiltrate, the amount of water added is 20% of the weight of the mixed raw materials, extruded into a spherical shape with a diameter of 10mm, and then roasted, the roasted The temperature is 650° C., and the calcination time is 1.5 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 7

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) collecting lake bottom mud as raw material, freeze-drying, and grinding through a 130-mesh sieve to obtain sediment powder for subsequent use;

(2) get zeolite, grind through 80 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Put the sediment powder processed in step (1) into a muffle furnace for constant temperature heating treatment, the heating temperature is 300°C, heat for 1.5 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 50% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw materials mixed in step (4), the amount of water added is 15% of the weight of the raw materials mixed, extruded into a spherical shape with a diameter of 5mm, and then roasted, the roasted The temperature is 600° C., and the calcination time is 2 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 8

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) collecting lake bottom mud as raw material, freeze-drying, and grinding through a 100-mesh sieve to obtain sediment powder for subsequent use;

(2) get zeolite, grind through 100 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Put the sediment powder processed in step (1) into a muffle furnace for constant temperature heating treatment, the heating temperature is 600°C, heat for 2 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 40% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw materials mixed in step (4), the amount of water added is 12% of the weight of the raw materials mixed, extruded into a spherical shape with a diameter of 7mm, and then roasted, the roasted The temperature is 600° C., and the calcination time is 2 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 9

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) collecting lake bottom mud as raw material, freeze-drying, and grinding through a 100-mesh sieve to obtain sediment powder for subsequent use;

(2) get zeolite, grind through 100 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Put the sediment powder processed in step (1) into a muffle furnace for constant temperature heating treatment, the heating temperature is 100°C, heat for 2 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 30% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw material mixed in step (4), the amount of water added is 14% of the weight of the raw material mixed, extruded into flakes, and then roasted, the temperature of the roasted is 600 °C, and the calcination time is 2 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 10

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) Collect lake bottom mud as raw material, freeze-dry, and grind through a 100-mesh sieve to obtain sediment powder for subsequent use _; wherein, the _SiO2 content in the lake bottom mud is 21.14%, and the _Al2O3 content is 45.26%, Fe ₂ O ₃ content is 22.01%, CaO content is 5.13%, MgO content is 3%, K ₂ O content is 0.46%, TiO ₂ content is 3%; the loss on ignition of the lake sediment is 30.43 %;

(2) get zeolite, grind through 100 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Place the sediment powder processed in step (1) in a muffle furnace for constant temperature heating treatment, the heating temperature is 200°C, heat for 2 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 20% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw material mixed in step (4), the amount of water added is 13% of the weight of the raw material mixed, extruded into blocks, and then roasted, the temperature of the roasted is 600 °C, and the calcination time is 2 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 11

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) Collect lake bottom mud as raw material, freeze-dry, and grind through a 100-mesh sieve to obtain sediment powder for subsequent use _; wherein, the _SiO2 content in the lake bottom mud is 22.92%, and the _Al2O3 content is 44.56%, Fe ₂ O ₃ content is 22.01%, CaO content is 5.13%, MgO content is 2.81%, K ₂ O content is 0.46%, TiO ₂ content is 2.11%; the loss on ignition of the lake sediment is 30.43 %;

(2) get zeolite, grind through 100 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Put the sediment powder processed in step (1) into a muffle furnace for constant temperature heating treatment, the heating temperature is 300°C, heat for 2 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 45% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw material mixed in step (4), the amount of water added is 13% of the weight of the raw material mixed, extruded into flakes, and then roasted, the temperature of the roasted is 600 °C, the roasting time is 2 hours, and the sediment/zeolite nitrogen-controlling material is obtained.

Example 12

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) Collect lake bottom mud as raw material, freeze-dry, and grind through a 100-mesh sieve to obtain sediment powder for subsequent use; wherein, the _SiO2 content in the lake bottom mud is ₂₅ %, and the _Al2O3 content is 40%, Fe ₂ O ₃ content is 25%, CaO content is 3%, MgO content is 4%, K ₂ O content is 1%, TiO ₂ content is 2%; The loss on ignition of the lake bottom mud is 32% %;

(2) get zeolite, grind through 100 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Place the sediment powder processed in step (1) in a muffle furnace for constant temperature heating treatment, the heating temperature is 400°C, heat for 2 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 35% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw material mixed in step (4), the amount of water added is 13% of the weight of the raw material mixed, extruded into a porous shape, and then roasted, the temperature of the roasted is 600 °C, and the calcination time is 2 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 13

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) Collect lake bottom mud as raw material, freeze-dry, and grind through a 100-mesh sieve to obtain sediment powder for subsequent use _; wherein, the _SiO2 content in the lake bottom mud is 23.14%, and the _Al2O3 content is 45.26%, Fe ₂ O ₃ content is 22.01%, CaO content is 5.13%, MgO content is 3%, K ₂ O content is 0.46%, TiO ₂ content is 1%; the loss on ignition of the lake sediment is 30.43 %;

(2) get zeolite, grind through 100 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Put the sediment powder processed in step (1) into a muffle furnace for constant temperature heating treatment, the heating temperature is 500°C, heat for 2 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 10% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw material mixed in step (4), the amount of water added is 13% of the weight of the raw material mixed, extruded into blocks, and then roasted, the temperature of the roasted is 600 °C, and the calcination time is 2 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 14

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) Collect lake bottom mud as raw material, freeze-dry, and grind through a 100-mesh sieve to obtain sediment powder for subsequent use; wherein, the _SiO2 content in the lake bottom mud is ₂₀ %, and the _Al2O3 content is 50%, the content of _Fe2O3 is ₂₀ %, the content of CaO is 8%, the content of MgO is ₁ %, the content of K2O is 0.1%, and the content of _TiO2 is 1.9%; the loss on ignition of the lake sediment is 30.43 %;

(2) get zeolite, grind through 100 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Put the sediment powder processed in step (1) into a muffle furnace for constant temperature heating treatment, the heating temperature is 700°C, heat for 2 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 30% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw material mixed in step (4), the amount of water added is 13% of the weight of the raw material mixed, extruded into flakes, and then roasted, the temperature of the roasted is 600 °C, and the calcination time is 2 hours to obtain the sediment/zeolite nitrogen-controlling material.

Example 15

A method for preparing sediment/zeolite nitrogen-controlling materials from lake sediment described in this embodiment comprises the following steps:

(1) Collect lake bottom mud as raw material, freeze-dry, and grind through a 100-mesh sieve to obtain sediment powder for subsequent use _; wherein, the _SiO2 content in the lake bottom mud is 22.92%, and the _Al2O3 content is 44.56%, Fe ₂ O ₃ content is 22.01%, CaO content is 5.13%, MgO content is 2.81%, K ₂ O content is 0.46%, TiO ₂ content is 2.11%; the loss on ignition of the lake sediment is 30.43 %;

(2) get zeolite, grind through 100 mesh sieves, obtain zeolite powder, for subsequent use;

(3) Place the sediment powder processed in step (1) in a muffle furnace for constant temperature heating treatment, the heating temperature is 800°C, heat for 2 hours, then cool to room temperature, and set aside;

(4) Add the zeolite powder in proportion to the sediment powder after step (3), the zeolite accounts for 90% of the total mass of the mixed raw materials, mix evenly, and set aside;

(5) Add water to soak in the raw material mixed in step (4), the amount of water added is 13% of the weight of the raw material mixed, extruded into blocks, and then roasted, the temperature of the roasted is 600 °C, and the calcination time is 2 hours to obtain the sediment/zeolite nitrogen-controlling material.

Experimental example

This experimental example investigates the effect of sediment/zeolite nitrogen control materials on the thermodynamic parameters of ammonia nitrogen adsorption at different concentrations and the removal effect of ammonia nitrogen in sediment interstitial water.

1. Experimental materials

Sample: the sediment/zeolite nitrogen-controlling material prepared according to the method of Example 8, wherein the percentages of the zeolite in step (4) accounting for the total mass of the mixed raw materials are set to 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% are samples;

Ammonium stock solution: Weigh 3.8190g of high-grade pure ammonium chloride (NH ₄ Cl) dried at 100°C and dissolve it in ammonia-free water, and set the volume to 1000mL. This solution contains 1mg of ammonia nitrogen per milliliter. 0, 0.1, 0.4, 0.8, 1.2, 3, 5, 10, 20, 40, 80, 120, 150, 200mg/L ammonia nitrogen solution, for later use.

2. Experimental method

1. Evaluation of the adsorption performance of sediment/zeolite nitrogen control materials on ammonia nitrogen

Through high-concentration ammonia nitrogen adsorption thermodynamic experiments, the influence of the sediment/zeolite nitrogen control material of the present invention on the maximum adsorption capacity of ammonia nitrogen is simulated.

Specific steps are as follows:

Weigh 0.5 g of the sediment/zeolite nitrogen-controlling material in different proportions into a 100 mL centrifuge tube, and add 50 mL of NH ₄ Cl solutions of different concentration series (0, 25, 50, 100, 125, 150, 175, 200 , 225, 250, 275, 300mg/L), put it in a constant temperature shaker at 25°C, shake at 200rpm for 4h, then take out the centrifuge tube, centrifuge at 5000r/min for 15min, pass through a 0.45μm filter membrane, and take the supernatant for determination Ammonia concentration.

Through the calculation of experimental data, the adsorption isotherms of high-concentration ammonia nitrogen with different ratios of sediment/zeolite nitrogen-controlling materials were obtained, as shown in Figure 2. Using the Langmuir model fitting calculation, different ratios of sediment/zeolite nitrogen-controlling materials were obtained. The maximum adsorption capacity of ammonia nitrogen is shown in Figure 3. Among them, the Langmuir equation is as follows:

Q＝ _Qmax ×C/( _Kd +C)

In the formula: Q is the equilibrium adsorption amount of sample ammonia nitrogen in mg/kg; Q _max is the maximum adsorption amount in mg/kg; C is the concentration of ammonia nitrogen in the equilibrium solution in mg/L.

2. Evaluation of adsorption-desorption characteristics of sediment/zeolite nitrogen-controlling materials for ammonia nitrogen

Through low-concentration ammonia nitrogen adsorption thermodynamic experiments, the influence of the sediment/zeolite nitrogen control material of the present invention on ammonia nitrogen adsorption-desorption parameters is simulated.

Specific steps are as follows:

Weigh 0.5 g of the sediment/zeolite nitrogen-controlling material in different proportions into a 100 mL centrifuge tube, and add 50 mL of NH ₄ Cl solutions of different concentration series (0.0, 0.15, 0.30, 0.45, 0.60, 0.75, 0.90, 1.05 . membrane, and the supernatant was taken to measure the concentration of ammonia nitrogen.

Through the calculation of experimental data, the adsorption isotherms of low-concentration ammonia nitrogen with different ratios of sediment/zeolite nitrogen-controlling materials were obtained, as shown in Figure 1. Using the linear distribution model fitting operation, different ratios of sediment/zeolite nitrogen-controlling materials were obtained The adsorption-desorption equilibrium concentration of ammonia nitrogen (as shown in Figure 3). Among them, the linear equation is as follows:

Q=a+b*C

ENC ₀ = (-a)/b

Q is the equilibrium adsorption amount of ammonia nitrogen in the sample, mg/kg; C is the concentration of ammonia nitrogen in the equilibrium solution, mg/L; ENC ₀ is the adsorption-desorption equilibrium concentration.

3. The removal effect of sediment/zeolite nitrogen control materials on different concentrations of ammonia nitrogen in sediment interstitial water

Take the 0-20cm bottom mud of Dianchi Lake, centrifuge it at 5000r/min for 5-30min, take the supernatant and pass it through a 0.45um microporous membrane to obtain the sediment interstitial water, and use the ammonia nitrogen standard stock solution to prepare the sediment interstitial water to the ammonia nitrogen concentration 0.8, 1.2, 2, 3, 5, 10 and 20 mg/l interstitial aqueous solution, mix the prepared sediment/zeolite nitrogen control material according to the ratio of water:material mass percentage of 100:1, and then in 25 ℃ , mixed and oscillated in a 200r/min constant temperature oscillator for 4h, 8h, 12h and 24h, and the test and calculation obtained the removal effect of sediment/zeolite nitrogen-controlling materials on different concentrations of ammonia nitrogen in sediment interstitial water (Figure 4).

3. Experimental results

Since the basic framework of zeolite is composed of silicon-oxygen (SiO ₄ ) tetrahedrons and aluminum-oxygen (AlO ₄ ) tetrahedrons connected to each other, in which the valence electrons of one oxygen atom in the aluminum-oxygen tetrahedrons are not neutralized and are negatively charged, In order to maintain charge neutrality, a nearby positively charged cation (M+) must be adsorbed. However, these cations have a weak binding ability to aluminosilicate, so they show a strong cation exchange capacity. For details, see "Theremoval of copper and nickel from aqueous solution using Y zeolite ionexchangers” (Keane M A. Colloids and Surfaces A: Physicochemical and Engineering Aspects 1998, 138 (1), 11-20.); Oxygen tetrahedrons are connected in different ways, and many pores and cavities will be formed in the zeolite structure. Considering both, zeolite exhibits strong ammonia nitrogen adsorption performance.

As can be seen from Fig. 3, in the material of the present invention, the ammonia nitrogen maximum adsorption capacity of the material containing 100% sediment is 3522mg/kg, and the adsorption-desorption equilibrium concentration is 0.21mg/l; The ammonia nitrogen maximum of the material containing 100% zeolite The adsorption capacity is 6615 mg/kg, and the adsorption-desorption equilibrium concentration is 0.22 mg/l. It shows that the adsorption performance of natural zeolite materials for ammonia nitrogen is significantly higher than that of pure sediment materials, but their desorption capacity for ammonia nitrogen is comparable. With the increase of the amount of zeolite mixed, the maximum adsorption capacity of the sediment/zeolite nitrogen-controlling material to ammonia nitrogen changes in an "M" curve, but the adsorption-desorption equilibrium concentration presents a "W" curve change, and the maximum adsorption capacity coincides with the minimum adsorption- Analytical equilibrium concentrations correspond. Therefore, we can optimize the optimal ratio of nitrogen control materials with high adsorption capacity and low desorption capacity, which are 40% zeolite, 60% zeolite and 70% zeolite respectively, and the ratio of 40% zeolite has the best effect and the lowest cost.

The removal effect of ammonia nitrogen in sediment interstitial water with different ratios of sediment/zeolite nitrogen control materials is shown in Figure 4. The nitrogen control materials with a ratio of 40%-80% zeolite have a better removal effect on ammonia nitrogen. Among them, 40% zeolite Compared with the nitrogen control materials, the removal effect of ammonia nitrogen concentration in sediment interstitial water is the best, especially for interstitial water with low ammonia nitrogen concentration.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, on the basis of the above description, other changes or changes in different forms can also be made. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (10)

1. one kind utilizes the method that bottom mud in lake prepares deposit/zeolite control nitrogen material, it is characterised in that Comprise the steps:

(1) gathering bottom mud in lake, freeze-dried, grinding is sieved, and obtains deposit powder body, standby；

(2) taking zeolite, grinding is sieved, and obtains zeolite powder body, standby；

(3) take step (1) to process the described deposit powder body that obtains and carry out heated at constant temperature process, then Cooling, standby；

(4) the described deposit powder body after step (3) processes is proportionally added into step (2) to process The described zeolite powder body obtained, mix homogeneously, standby；

(5) in step (4), the raw material of mixing adds water infiltration, extruded, then carry out roasting, Obtain described deposit/zeolite control nitrogen material.

Method the most according to claim 1, it is characterised in that in described step (4), described Zeolite powder body accounts for the 10%-90% of the gross mass of mixed raw material.

Method the most according to claim 1 and 2, it is characterised in that in described step (4), Described zeolite accounts for the 40%-70% of the gross mass of mixed raw material.

4. according to the method described in claim 1-3 any one, it is characterised in that described step (3) In, the temperature of described heated at constant temperature is 100-800 DEG C, and the time that described heated at constant temperature processes is 1-3 hour.

5. according to the method described in claim 1-4 any one, it is characterised in that described step (3) In, the temperature of described heated at constant temperature is 400-600 DEG C.

6. according to the method described in claim 1-5 any one, it is characterised in that described step (4) In, described zeolite accounts for the 40% of described mixing raw material gross mass.

7. according to the method described in claim 1-6 any one, it is characterised in that described step (5) In, the raw material of described mixing carries out the temperature of roasting and is 500-700 DEG C, and the time of described roasting is 1-3h.

8. according to the method described in claim 1-7 any one, it is characterised in that described step (5) In, described deposit/zeolite control nitrogen material be shaped as spherical, lamellar, bulk or cellular；Described The 10%-50% of the weight of the raw material that the water yield is described mixing added.

9. the deposit that the method described in claim 1-10 any one prepares/zeolite control nitrogen material Purposes at preparation ammonia nitrogen absorption Material Field.

Purposes the most according to claim 11, it is characterised in that described ammonia nitrogen absorption material is Lake sediment ammonia nitrogen release resistance control material.