A biological filter material ceramsite for removing perchlorate in water and a preparation method thereof
By loading iron onto biological filter ceramic particles, iron-modified biological filter ceramic particles are prepared, which solves the problem of low perchlorate removal efficiency in existing technologies and achieves efficient and low-cost perchlorate removal.
Patent Information
- Application Number
- CN202411933918.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-26
- Publication Date
- 2026-06-26
AI Technical Summary
Existing biological filter media, ceramic particles, have low efficiency in removing perchlorate from water, with no application cases observed, and their preparation methods are complex and costly.
Iron-modified biological filter media ceramics were prepared by loading iron onto the filter media ceramic particles, thereby enhancing their ability to remove perchlorate. The method involved mixing, soaking, and drying the filter media ceramic particles with an iron modifier.
It significantly improves the removal efficiency of perchlorate by biological filter media ceramic particles, achieving a removal rate of over 50%, while being low in cost and simple and convenient.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the application of biological filter media ceramic particles in the field of water treatment, and more particularly to the use of iron salt modified biological filter media ceramic particles for the removal of perchlorate in water treatment processes. Background Technology
[0002] Biological filter media ceramsite is a granular water treatment material made primarily from high-quality clay and fly ash through a series of processes including drying, batching, pulverizing, pelletizing, high-temperature calcination, and sieving. In terms of its physical microstructure, this product features a well-developed and rationally distributed surface with an average micropore diameter of approximately 200 micrometers. Microorganisms growing within these micropores are not easily lost, maintaining their inoculum even during prolonged periods of inactivity, enabling aerated biological filters to operate intermittently for extended periods. Simultaneously, its large specific surface area facilitates the attachment, growth, and reproduction of numerous microorganisms, increasing the volumetric loading rate and significantly improving the degradation rate of the aerated biological filter. Furthermore, this product is lightweight, high-strength, abrasion-resistant, washout-resistant, and does not release toxic or harmful substances into the water. It possesses excellent physical, chemical, and hydraulic stability properties, making it suitable for various water treatment scenarios. With the increasing water reuse rate and stricter emission standards, biological filter media ceramsite has become the preferred filter material for water treatment, particularly for municipal sewage and industrial wastewater treatment, and for the biological pretreatment of slightly polluted water sources, with its application range becoming increasingly wide.
[0003] Biological filter media ceramsite exhibits excellent removal efficiency for phosphorus, ammonia nitrogen, and COD, with strong interception capacity and high-quality effluent. Optimized particle size distribution further enhances its dirt-holding capacity and increases filter media utilization, while slowing down the increase in head loss. The filtration rate of biological filter media ceramsite can reach 16 m / h, with a working cycle exceeding 24 hours and a cycle water production efficiency of 800-1000 m³ / h. 3 / m 2 It is 1.5-2 times that of quartz sand filter media. Nevertheless, there are currently no reported cases of the application of biological filter media ceramsite in the treatment of perchlorate-containing water. Summary of the Invention
[0004] The purpose of this invention is to address the shortcomings of existing biological filter media ceramic particles that do not remove perchlorate, and the lack of preparation of such particles, as well as the low removal efficiency of directly removing perchlorate using ceramic particles. This invention provides a heated filter media ceramic particle capable of removing perchlorate from water, along with its preparation method. The preparation method of this invention enhances the removal capacity of the biological filter media ceramic particles for perchlorate by loading iron onto them. The prepared biological filter media ceramic particles have a high saturated adsorption capacity for perchlorate, and the biological filter media ceramic particles prepared using this invention can significantly remove perchlorate from water, with a removal efficiency of over 50%. The iron-modified biological filter media ceramic particles prepared by this invention have a significant removal effect on perchlorate in water, and the preparation method is simple, convenient, and inexpensive.
[0005] To achieve the objectives of this invention, one aspect of this invention provides a method for preparing biological filter media ceramic particles that can remove perchlorate from water, comprising mixing the filter media ceramic particles with an iron modifier and then soaking them.
[0006] The particle size of the filter media ceramic particles is 3-15mm.
[0007] In particular, the apparent density of the filter media ceramsite is 1.4–1.65 g / cm³. 3 The bulk density is 0.8–1.3 g / cm³. 3 Intragranular porosity 40–75%; Packing void ratio 45–80%; Specific surface area ≥4 m² 2 / g; wear rate <2.2%.
[0008] In particular, the iron modifier is an Fe-containing agent. 2+ or Fe 3+ The solution, preferably containing Fe 3+ The solution.
[0009] In particular, the iron element concentration in the iron modifier is 0.1-1 g / L, preferably 0.5 g / L.
[0010] In particular, the mass ratio of iron in the iron modifier to the bio-filter ceramic particles is (0.01-0.1):1, preferably (0.03-0.07):1, and more preferably 0.05:1.
[0011] Another aspect of the present invention provides a method for modifying biological filter media ceramic particles capable of removing perchlorate from water, comprising the following steps:
[0012] 1) Pre-treat the filter media ceramic particles to obtain pre-treated filter media ceramic particles for later use;
[0013] 2) Mix the iron-containing compound with water to dissolve and prepare an iron modifier;
[0014] 3) Add the pretreated filter material ceramsite to the iron modifier, stir and mix evenly, then soak and dry to obtain the final product.
[0015] In particular, the pretreatment described in step 1) includes washing the filter media ceramic particles 5-10 times with clean water or deionized water, and then drying them at 100-120°C to constant weight.
[0016] In particular, during each washing of the ceramsite, the volume ratio of deionized water to ceramsite is (3-10):1), preferably 5:1.
[0017] In particular, the apparent density of the filter media ceramsite is 1.4–1.65 g / cm³. 3The bulk density is 0.8–1.3 g / cm³. 3 Intragranular porosity 40–75%; Packing void ratio 45–80%; Specific surface area ≥4 m² 2 / g; wear rate <2.2%.
[0018] In particular, the iron concentration in the iron modifier described in step 2) is 0.1-1 g / L, preferably 0.5 g / L.
[0019] In particular, the iron-containing compound mentioned in step 2) is ferric sulfate (Fe2(SO4)3), ferrous sulfate, ferric nitrate, ferrous nitrate, ferrous chloride, or ferric chloride (FeCl3), preferably ferric sulfate.
[0020] In particular, the mass ratio of iron in the iron modifier to the pretreated filter media ceramsite in step 3) is (0.01-0.1):1, preferably (0.03-0.07):1, and more preferably 0.05:1.
[0021] In particular, the soaking treatment temperature is room temperature, usually 10-40℃, preferably 15-30℃, and more preferably 25℃; the soaking treatment time is 1-4h, preferably 2h.
[0022] In particular, the process of mixing the iron modifier with the pretreated filter material ceramic particles in step 3) and soaking them at room temperature is carried out by oscillation in a low-temperature air bath oscillator.
[0023] In particular, the temperature of the oscillation treatment in step 3) is 10-40℃, preferably 25℃; the oscillation rate is 100-200rpm, preferably 100rpm; and the oscillation treatment time is 1-4h, preferably 2h.
[0024] In particular, the uniformly mixed filter media ceramic particles and iron modifier are subjected to the soaking treatment under oscillation conditions.
[0025] In particular, the soaking process is performed by oscillation in a low-temperature gas bath oscillator.
[0026] In particular, the oscillation rate is 100-200 rpm, preferably 100 rpm.
[0027] In particular, the drying temperature is 100-120°C; the drying time is 4-8 hours, preferably 5 hours.
[0028] In particular, the process includes filtering the mixture after oscillation treatment, rinsing the solid filter residue with deionized water at least 3-5 times, and then drying the iron-modifying agent-impregnated biological filter ceramsite at 100-120°C; the drying time is 4-8 hours, preferably 5 hours, and the modified biological filter ceramsite is obtained after drying.
[0029] In another aspect, the present invention provides a biological filter media ceramic particle that can remove perchlorate from water, prepared according to the above method.
[0030] In another aspect, the present invention provides an application of the biological filter media ceramic particles prepared according to the above method in the removal of perchlorate from water.
[0031] The present invention has the following beneficial effects:
[0032] (1) The method of the present invention opens up a new path for the application of traditional biological filter material ceramic particles in perchlorate removal;
[0033] (2) The preparation method of the iron-modified biological filter ceramic particles of the present invention is simple and convenient. By combining iron ions with biological filter ceramic particles, the specific surface area of iron compounds is increased, and the biological filter ceramic particles are endowed with the function of removing perchlorate.
[0034] (3) The preparation method of iron-modified biological filter material ceramic particles of the present invention is low in cost, low in material consumption and energy consumption, and meets the requirements of low energy consumption, energy saving and environmental protection.
[0035] (4) The present invention is a biological filter ceramic particle for removing perchlorate from water by impregnating the filter ceramic particle with iron salt and loading iron salt on the biological filter ceramic particle; the iron modified biological filter ceramic particle of the present invention can synergistically exert the physical and chemical effects and microbial degradation function of the material during the application process, thereby enhancing the biological filter ceramic particle's ability to treat perchlorate and achieving a perchlorate removal rate of more than 50%.
[0036] 5. The iron-modified biological filter media ceramsite prepared by the method of the present invention has a saturated adsorption capacity of more than 87.867 mg / g for perchlorate, that is, the iron-modified biological filter media ceramsite of the present invention has a removal capacity of more than 87.867 mg / g for perchlorate. Attached Figure Description
[0037] Figure 1 This is a comparison chart showing the perchlorate removal capabilities of iron-modified biological filter media ceramsite and unmodified filter media ceramsite prepared by the method of this invention. Detailed Implementation
[0038] The present invention will be further described below with reference to specific implementation examples. Although detailed implementation methods and specific operation processes are given in the examples, the specific details in the examples are only for illustrating the present invention and do not represent all technical solutions under the concept of the present invention. Those skilled in the art can refer to the content of the present invention and appropriately change the raw materials and process parameters to realize the technology of the present invention, but all such changes are considered to be included in the spirit, scope and content of the present invention.
[0039] Example 1
[0040] This example demonstrates the preparation of iron-modified biological filter media ceramsite using the following method, which was then used to remove perchlorate from water:
[0041] 1. Pretreatment of filter media ceramic particles
[0042] Filter media ceramic particles with a particle size of 6-10mm are washed 5 times (usually 5-10 times) with deionized water. During each washing process, the volume ratio of deionized water to ceramic particles is 5:1 (usually (3-10):1). Then, the filter media ceramic particles are dried in an oven at a temperature of 105±5℃ (usually 100-120℃) until constant weight is obtained to obtain pretreated filter media ceramic particles for later use.
[0043] The filter media ceramsite suitable for this invention has a particle size of 6-10 mm and an apparent density of 1.4-1.65 g / cm³. 3 The bulk density is 0.8–1.3 g / cm³. 3 The particle porosity is 40-75%, the packing void ratio is 45-80%, the specific surface area is ≥4m² / g, and the wear rate is <2.2%.
[0044] 2. Preparation of iron modifier
[0045] Weigh 1.79g of ferric sulfate and dissolve it in a 1000mL volumetric flask. Add water to the mark and shake well to prepare an iron modifier with an iron concentration of 0.5g / L (the iron content in the iron modifier is usually 0.1-1g / L).
[0046] In a specific embodiment of the present invention, the concentration (or content) of iron in the iron modifier is 0.5 g / L as an example. Other iron contents, such as 0.1-1 g / L, are also applicable to the present invention.
[0047] In the specific embodiments of the present invention, ferric sulfate is used as an example of an iron-containing compound. Other iron-containing compounds such as ferrous sulfate, ferric chloride, ferrous chloride, ferric nitrate, and ferrous nitrate are also applicable to the present invention.
[0048] 3. Modification treatment
[0049] Add 10g of pretreated filter media ceramic particles to each of three 200mL conical flasks, and add 200mL of the iron modifier prepared in step 2) to each conical flask. The iron modifier immerses the filter media ceramic particles. The mass ratio of iron element in the iron modifier to the mass of filter media ceramic particles is 0.01:1 (usually (0.005-0.1):1).
[0050] After stirring evenly, the conical flask is placed in a low-temperature gas bath shaker. Under shaking conditions, the iron modifier is used to impregnate the filter media ceramic particles to modify them, thus obtaining iron salt modified biological filter media ceramic particles. The modification treatment temperature is 25℃ (usually 10-40℃); the modification treatment time is 2h (usually 1-4h); and the shaking speed is 100rpm (usually 100-200rpm).
[0051] The biological filter media modification treatment temperature of the present invention is selected at 10-40℃, which not only reduces energy consumption, but also reduces the modification time and improves the efficiency of the modification treatment.
[0052] This invention has found that increasing the iron content while keeping the mass of the expanded clay particles constant increases the opportunity for contact and ion exchange between the iron in the modified biological filter media and perchlorate ions. However, as the iron content increases, the porosity and adsorption sites of the expanded clay particles themselves become more limited, meaning that the adsorption and removal effect on perchlorate does not increase with the increase in iron content. Therefore, the mass ratio of iron in the iron modifier to the pretreated filter media expanded clay particles is (0.01-0.1):1, preferably (0.03-0.07):1, and more preferably 0.05:1.
[0053] 4. Washing and drying
[0054] After 2 hours of modification treatment, the biological filter ceramic particles soaked and wetted with iron modifier were removed.
[0055] Rinse the filter media ceramic particles with deionized water 4 times (usually at least 3 times, preferably 3-5 times);
[0056] Then, the rinsed filter media ceramic particles are placed in an oven at a temperature maintained at 110℃ (usually 100-120℃) for drying for 5 hours (usually 4-8 hours) to obtain the iron salt modified biological filter media ceramic particles of the present invention (denoted as 0.01 ceramic particles).
[0057] The biological filter media ceramsite of this invention contains clay with excellent adsorption properties, especially for metal ions. Furthermore, clay minerals have a large specific surface area and high cation exchange capacity, enabling the ceramsite to effectively adsorb heavy metal ions, including iron ions.
[0058] The clay in the biological filter media, ceramsite, adsorbs heavy metal ions through its unique layered structure and surface charge characteristics. Furthermore, the tetrahedral or octahedral clay in the ceramsite is prone to isomorphic substitution, leading to charge imbalance and exposing oxygen atoms on the fracture surfaces of the clay components. These oxygen atoms carry a permanent negative charge, strongly attracting metal ions. In addition, the fine particle size, unsaturated charge, large specific surface area, and interlayer domains of the clay mineral components in the ceramsite all contribute to the adsorption of water and cations, further enhancing the adsorption capacity of the biological ceramsite. The iron ions in the iron modifier are adsorbed onto the ceramsite, achieving iron modification. The iron ions adsorbed on the ceramsite then undergo ion exchange with perchlorate ions in the water, achieving efficient removal of perchlorate from the water.
[0059] Example 2
[0060] 1) Pretreatment of filter media ceramic particles
[0061] The same as step 1) of Example 1.
[0062] 2) Preparation of iron modifier
[0063] Except for weighing 0.358g of ferric sulfate and preparing an iron modifier with an iron concentration of 0.1g / L, the rest is the same as step 2) of Example 1.
[0064] 3. Modification treatment
[0065] Except that the mass ratio of iron element in the iron modifier to the mass of filter media ceramic particles is 0.03:1; the modification treatment temperature is 20℃ (usually 10-40℃); the modification treatment time is 4h (usually 1-4h); the rest is the same as step 3) of Example 1 (denoted as 0.03 ceramic particles).
[0066] 4. Washing and drying
[0067] The same as step 4) in Example 1.
[0068] Example 3
[0069] 1) Pretreatment of filter media ceramic particles
[0070] The same as step 1) of Example 1.
[0071] 2) Preparation of iron modifier
[0072] Except for weighing 3.58g of ferric sulfate and preparing an iron modifier with an iron concentration of 1g / L, the rest is the same as step 2) of Example 1.
[0073] 3. Modification treatment
[0074] Except that the mass ratio of iron element in the iron modifier to the mass of filter media ceramic particles is 0.07:1; the modification treatment temperature is 10℃ (usually 10-40℃); the modification treatment time is 1h (usually 1-4h); the rest is the same as step 3) of Example 1 (denoted as 0.07 ceramic particles).
[0075] 4. Washing and drying
[0076] The same as step 4) in Example 1.
[0077] Example 4
[0078] 1) Pretreatment of filter media ceramic particles
[0079] The same as step 1) of Example 1.
[0080] 2) Preparation of iron modifier
[0081] The same as step 2) in Example 1.
[0082] 3. Modification treatment
[0083] Except that the mass ratio of iron element in the iron modifier to the mass of filter media ceramic particles is 0.05:1; the modification treatment temperature is 30℃ (usually 10-40℃); the modification treatment time is 3h (usually 1-4h); the rest is the same as step 3) of Example 1 (denoted as 0.05 ceramic particles).
[0084] 4. Washing and drying
[0085] The same as step 4) in Example 1.
[0086] Experimental Example: Removal of Perchlorate from Iron-Modified Biofilter Ceramic Particles
[0087] Take 10g of each of the iron salt modified biological filter media ceramic particles prepared in Examples 1-4 and place them in 4 groups of 500mL Erlenmeyer flasks, with 3 Erlenmeyer flasks in each group. Also take 10g of each of the 3 unmodified biological filter media ceramic particles and place them in 3 groups of 500mL Erlenmeyer flasks as controls.
[0088] Add 200 mL of the prepared sodium perchlorate solution (10 g / L) to each of the conical flasks. Place the flasks in a shaker and shake for 2 hours at 25°C and 200 rpm. After shaking, take 2 mL of the supernatant from each flask and use an ion chromatograph to detect the remaining concentration of perchlorate in the supernatant. The results are as follows. Figure 1 As shown.
[0089] The removal rate of perchlorate is calculated according to formula (1): Formula (1) is as follows:
[0090]
[0091] In formula (1): C0—the original concentration of the perchlorate solution before adsorption, mg / L; C i —The concentration of perchlorate in the effluent, mg / L, after a period of adsorption.
[0092] The adsorption capacity of biological filter media ceramic particles for perchlorate is calculated according to formula (2), which is as follows:
[0093]
[0094] In formula (2): C0—the original concentration of the perchlorate solution before adsorption, mg / L; C t —Concentration of perchlorate in the effluent after 2 hours of adsorption, mg / L; V —Volume of adsorbate solution, mL; M —Mass of adsorbent biological filter media ceramic particles, g.
[0095] The results of the determination of the unit adsorption capacity of biological filter media ceramic particles for perchlorate (the saturated adsorption capacity of modified biological filter media ceramic particles for perchlorate) are as follows: Figure 1 As shown.
[0096] Figure 1 The test results show that the iron salt modified biological filter media ceramic particles can efficiently remove perchlorate, with a perchlorate removal rate of over 50%; the perchlorate removal rate of the original ceramic particles is 20.15%, and the perchlorate removal rate of the iron salt modified biological filter media ceramic particles prepared by the method of this invention is significantly improved.
[0097] Under the above-mentioned influent and application conditions, the iron-modified biological filter media ceramic particles prepared using the method of the present invention can achieve a maximum perchlorate removal capacity of 87.867 mg / g (that is, the saturated adsorption capacity of iron-modified biological filter media ceramic particles for perchlorate is 87.867 mg / g).
Claims
1. A method for producing a biological filter material ceramsite for removing perchlorate from water, characterized by, This includes mixing filter media ceramic particles with an iron modifier and then subjecting them to vibration treatment to obtain iron-modified biological filter media ceramic particles.
2. The production method according to claim 1, wherein The particle size of the biological filter media ceramic particles is 3-15mm.
3. The production method according to claim 1, wherein The concentration of the iron modifier is 0.1-1 g / L.
4. The production method according to claim 1, wherein The mass ratio of iron to biological filter media ceramsite in the iron modifier is (0.01-0.1):1, preferably (0.03-0.07):1, and more preferably 0.05:
1.
5. A method for producing a biological filter material ceramsite for removing perchlorate from water, characterized by, The steps include the following: A) The filter media ceramic particles are washed and pretreated, then dried to obtain pretreated filter media ceramic particles for later use; B) Mix the iron-containing compound with water to dissolve and prepare an iron modifier; C) Mix the iron modifier with the pretreated filter media ceramic particles, stir and vibrate to impregnate the pretreated filter media ceramic particles with the iron modifier, and the product is obtained.
6. The production method according to claim 5, wherein The iron-containing compound in step B) is a compound containing Fe 2+ or Fe 3+ .
7. The production method according to claim 5, wherein The iron-containing compound mentioned in step B) is ferric sulfate, ferrous sulfate, ferric nitrate, ferrous nitrate, ferrous chloride, or ferric chloride.
8. The production method according to claim 5, wherein In step C), the mass ratio of iron in the iron modifier to the biological filter media ceramic particles is (0.01-0.1):1, preferably (0.03-0.07):1, and more preferably 0.05:
1.
9. A biological filter material ceramsite for removing perchlorate from water, characterized by, Prepared according to the method described in any one of claims 1-8.