Purification method for perchlorate-containing wastewater and application

Abstract

The application belongs to the technical field of wastewater treatment, and particularly relates to a purification treatment method and application of perchlorate wastewater. The method comprises the following steps: after first filtration treatment, anaerobic bacteria treatment and second filtration treatment of the perchlorate wastewater, purified wastewater is obtained; in the anaerobic bacteria treatment, the perchlorate wastewater is subjected to anaerobic treatment by using an anaerobic bacteria molecular sieve. The purification treatment method of the perchlorate wastewater provided by the application removes solid particles, heavy metal ions and part of the perchlorate in the perchlorate wastewater through the first filtration treatment; the perchlorate is decomposed to obtain chloride ions through the anaerobic bacteria treatment, and then the chloride salt is absorbed through the second filtration treatment for resource utilization. The method is widely applicable to perchlorate wastewater in various fields.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a method and application for purifying perchlorate wastewater. Background Technology

[0002] Perchlorate wastewater poses a potential hazard to the environment and human health. It can rapidly spread through water systems, entering surface water bodies such as rivers and lakes, as well as groundwater. If these water bodies are used as drinking water sources, it will inevitably harm human drinking water, directly impacting human health. Furthermore, perchlorate can interfere with thyroid function, affecting the health of humans and animals, especially the brain development of children. Therefore, perchlorate wastewater is an environmental problem that requires serious attention.

[0003] Currently, the main methods for treating perchlorate wastewater include: biological reduction, chemical reduction, membrane separation, electrochemical methods, and ion exchange. Biological or chemical reduction methods require the addition of organic or inorganic substances, which can cause secondary pollution of the wastewater. Membrane separation or electrochemical methods alone are costly and economically inefficient. While ion exchange is simple to operate and highly efficient, it can only treat wastewater containing low to medium concentrations of perchlorate, and the replacement and regeneration of the resin are also costly. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method and application for purifying perchlorate wastewater. The method combines multiple separation technologies to reduce the frequency of membrane and resin replacements, thereby lowering treatment costs. The treated wastewater exhibits a perchloric acid concentration below 0.35 mg / L, meeting discharge standards. This method is widely applicable to perchlorate wastewater in various fields.

[0005] This invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a method for purifying perchlorate wastewater, comprising the following steps:

[0007] After the perchlorate wastewater undergoes a first filtration treatment, an anaerobic bacteria treatment, and a second filtration treatment, purified wastewater is obtained.

[0008] In the anaerobic treatment, anaerobic molecular sieves are used to anaerobic treat the perchlorate wastewater.

[0009] The present invention provides a method for purifying perchlorate wastewater. A first filtration process removes solid particles, heavy metal ions, and some perchlorate from the wastewater. Anaerobic bacteria decompose perchlorate ions to obtain chloride ions, which are then absorbed by a second filtration process for resource recovery. This method is widely applicable to perchlorate wastewater in various fields.

[0010] In some possible implementations, the preparation of the anaerobic molecular sieve includes the following steps:

[0011] After loading polylactic acid binder onto the surface of the molecular sieve, an anaerobic bacteria spray solution is sprayed on it, and then dried and cured to obtain the anaerobic bacteria molecular sieve.

[0012] The anaerobic spray solution contains anaerobic bacteria, lecithin, and water;

[0013] The polylactic acid binder contains polylactic acid, lecithin, and ethanol.

[0014] In some possible implementations, the mass ratio of the anaerobic bacteria, the lecithin, and the water in the anaerobic bacterial spray is 0.23:(2-3):(1-3).

[0015] In some possible implementations, the mass ratio of polylactic acid, lecithin, and ethanol in the polylactic acid binder is (30-50):(5-10):1.

[0016] In some possible implementations, the polylactic acid has an average molecular weight of 800 to 1000.

[0017] In some possible implementations, the step of loading the polylactic acid binder onto the surface of the molecular sieve includes:

[0018] Molecular sieves are impregnated in polylactic acid binder, filtered, and then dried to a semi-cured state.

[0019] In some possible implementations, the preparation of the polylactic acid adhesive includes the following steps:

[0020] Under the condition of stirring speed of 30 rpm to 80 rpm, lecithin is added to ethanol, and polylactic acid powder is added in more than 10 portions. Stirring is continued for 10 min to 15 min to obtain the polylactic acid binder.

[0021] In some possible implementations, the preparation of the anaerobic bacterial spray solution includes the following steps:

[0022] Under the condition of stirring speed of 50 rpm to 100 rpm, lecithin is added to water, followed by anaerobic bacteria, and stirring is continued for 10 min to 15 min to obtain the anaerobic bacterial spray solution.

[0023] In some possible implementations, the first filtration process includes at least one of the following: gravel filtration, activated carbon filtration, PP cotton filtration, ultrafiltration membrane filtration, and reverse osmosis filtration.

[0024] In some possible implementations, the second filtration process includes screen filtration, and also includes at least one of ion exchange resin filtration and activated carbon filtration.

[0025] Secondly, the present invention provides an application of the purification and treatment method for perchlorate wastewater provided by the present invention in the field of perchlorate wastewater treatment. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described and illustrated below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0027] Obviously, the following description is merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0028] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand the invention and is not intended to limit the subject matter of the claims.

[0029] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

[0030] The following is a detailed description of a purification treatment method and application of perchlorate wastewater according to an embodiment of the present invention.

[0031] The term "content" refers to the mass fraction.

[0032] The first aspect of this invention provides a method for purifying perchlorate wastewater, comprising the following steps:

[0033] S10. After the perchlorate wastewater undergoes first filtration, anaerobic bacteria treatment, and second filtration, purified wastewater is obtained.

[0034] In anaerobic treatment, anaerobic molecular sieves are used to treat perchlorate wastewater anaerobically.

[0035] The purification method for perchlorate wastewater provided in this invention includes a first filtration treatment to remove solid particles, heavy metal ions, and some perchlorate from the wastewater, reducing salinity without affecting the activity of anaerobic bacteria. Anaerobic bacteria then decompose perchlorate ions to obtain chloride ions, which are subsequently absorbed by a second filtration treatment for resource recovery. This method is widely applicable to perchlorate wastewater in various fields.

[0036] In some embodiments, in step S10 above, the first filtration process includes at least one of the following: sand filtration, activated carbon filtration, PP cotton filtration, ultrafiltration membrane filtration, and reverse osmosis filtration. In this case, sand filtration, activated carbon filtration, PP cotton filtration, ultrafiltration membrane filtration, and reverse osmosis filtration are all conventional filtration technologies in the art, and their materials and other filtration conditions can be adjusted as needed, and are not particularly limited in this embodiment of the invention. Furthermore, in the first filtration process, the selection of various filters can be adjusted according to the actual situation, as long as the salt concentration in the water is between 5 g / L and 20 g / L.

[0037] In some embodiments, in step S10 above, the perchlorate in the perchlorate wastewater is at least one of potassium perchlorate, sodium perchlorate, and ammonium perchlorate.

[0038] In some embodiments, in step S10 above, after the perchlorate wastewater undergoes the first filtration treatment, the salt concentration in the water is 5 g / L to 20 g / L. In the example, it can be a typical but non-limiting concentration such as 5 g / L, 15 g / L, or 20 g / L, or any range between two concentrations.

[0039] In some embodiments, in step S10 above, the anaerobic bacteria are perchlorate-reducing bacteria QD19-16.

[0040] In some embodiments, the preparation of anaerobic molecular sieves in step S10 above includes the following steps:

[0041] S101. After loading polylactic acid binder onto the surface of the molecular sieve, spray it with anaerobic bacteria spray solution and dry and solidify it to obtain anaerobic bacteria molecular sieve.

[0042] The anaerobic spray solution contains anaerobic bacteria, lecithin, and water;

[0043] Polylactic acid binders contain polylactic acid, lecithin, and ethanol.

[0044] In the preparation of the anaerobic molecular sieve described above, polylactic acid (PLA) binder is first loaded onto the molecular sieve, and then an anaerobic bacterial spray is sprayed on top, allowing the anaerobic bacteria to effectively adhere and fix to the surface of the molecular sieve. PLA binds the anaerobic bacteria, lecithin provides energy for the anaerobic bacteria, maintaining their growth and activity, and water and ethanol are used as solvents to uniformly disperse the anaerobic bacteria, lecithin, PLA, and lecithin.

[0045] In some embodiments, in step S10 above, the mass ratio of polylactic acid binder, anaerobic bacterial spray, and molecular sieve is (50-80):(20-30):1. In exemplary cases, this can be a typical but non-limiting mass ratio such as 70:25:1, 50:20:1, 75:28:1, or 80:30:1, or any range between two mass ratios. In this case, the polylactic acid binder and anaerobic bacterial spray can fully fill the mesoporous surface of the molecular sieve, forming a saturated anaerobic bacterial molecular sieve.

[0046] In some embodiments, in step S101 above, the mass ratio of polylactic acid, lecithin, and ethanol in the polylactic acid binder is (30-50):(5-10):1. In exemplary cases, this can be a typical but non-limiting mass ratio such as 30:5:1, 40:8:1, 30:10:1, or 50:10:1, or any range between two mass ratios. In this case, the viscosity of the polylactic acid binder is moderate, suitable for loading onto molecular sieves.

[0047] In some embodiments, the average molecular weight of polylactic acid is 800 to 1000.

[0048] In some embodiments, the preparation of the polylactic acid adhesive in step S101 above includes the following steps:

[0049] Under the condition of stirring speed of 30 rpm to 80 rpm, lecithin is added to ethanol, and polylactic acid powder is added in more than 10 portions. Stirring is continued for 10 min to 15 min to obtain polylactic acid binder.

[0050] In some embodiments, the step of loading the polylactic acid binder onto the surface of the molecular sieve in step S101 above includes:

[0051] S1000. Molecular sieves are impregnated in polylactic acid binder, filtered, and then dried to a semi-cured state.

[0052] In some embodiments, the step of impregnating the molecular sieve in the polylactic acid binder in step S1010 above includes:

[0053] Molecular sieves were dispersed in polylactic acid binder solution at a stirring speed of 10 rpm to 20 rpm, and then stirred for 2 min to 10 min to obtain a suspension.

[0054] In some specific embodiments, in step S1010 above, filtration includes the following steps: filtering the suspension using an 80-100 mesh sieve to obtain filter residue. In this case, filtration removes small-sized, unloaded molecular sieve particles and excess polylactic acid binder.

[0055] In some specific embodiments, the drying temperature in step S1010 is 20℃~30℃. In this case, the drying time of the filter residue can be effectively controlled, allowing it to dry to a semi-solid state. It should be noted that the drying time depends on the actual amount of molecular sieve and polylactic acid binder used, and is not particularly limited in this embodiment of the invention, as long as it can be dried to a semi-solid state. The drying method is conventional in the art, but as an example, it can be air drying, natural drying, etc.

[0056] In some embodiments, in step S101 above, the average particle size of the molecular sieve is 170 μm to 250 μm. In an exemplary example, it can be a typical but non-limiting average particle size such as 200 μm or any range between two average particle sizes. In this case, the molecular sieve contains abundant mesopores, which can accommodate more anaerobic bacteria.

[0057] In some embodiments, the molecular sieve in step S101 above is a mesoporous molecular sieve. It should be noted that the pore size and material of the mesoporous molecular sieve can be selected as needed, and no particular limitation is made in this invention. However, as an example, the average pore size of the mesoporous molecular sieve is 30nm to 50nm, and the material is SBA-15, MCM-41, etc.

[0058] In some embodiments, the preparation of the anaerobic bacteria spray solution in step S101 above includes the following steps:

[0059] S1011. Under the condition of stirring speed of 50 rpm to 100 rpm, lecithin is added to water, then anaerobic bacteria are added, and stirring is continued for 10 min to 15 min to obtain anaerobic bacterial spray solution.

[0060] In some embodiments, in step S1011 above, the mass ratio of anaerobic bacteria, lecithin, and water in the anaerobic bacterial spray solution is 0.23:(2-3):(1-3). In exemplary cases, this can be a typical but non-limiting mass ratio such as 0.23:2:1, 0.23:3:2, or 0.23:2:3, or a range between any two mass ratios. In this case, lecithin provides all the nutrients necessary for the anaerobic bacteria to maintain growth and biological activity.

[0061] In some embodiments, in step S101 above, the drying and curing temperature is 15°C to 35°C. In an exemplary example, it can be a typical but non-limiting temperature such as 15°C, 20°C, or 30°C, or any range between two temperatures.

[0062] In some embodiments, in step S10 above, the anaerobic bacteria treatment includes the following steps:

[0063] S102. Add anaerobic molecular sieves at a stirring speed of 10 rpm to 30 rpm and continue stirring for 24 h to 48 h.

[0064] In some embodiments, in step S102 above, the amount of anaerobic molecular sieve added is 100 g / L to 200 g / L. In exemplary cases, it can be a typical but non-limiting addition amount such as 100 g / L, 150 g / L, or 200 g / L, or any range between two addition amounts. It should be noted that the amount of anaerobic molecular sieve added can also be changed according to the perchlorate content in the actual wastewater. The addition amount in this embodiment of the invention is only set for wastewater with a salt concentration of 5 g / L to 20 g / L.

[0065] In some embodiments, in step S10 above, the second filtration process includes screen filtration and at least one of ion exchange resin filtration and activated carbon filtration. In this case, screen filtration prevents anaerobic bacteria from entering the next process, avoiding material contamination. The ion exchange resin and activated carbon adsorb chloride ions obtained from the decomposition of anaerobic bacteria in the water, as well as undecomposed perchlorate, chlorate, and chlorite ions. It should be noted that the materials used for the ion exchange resin to adsorb perchlorate are conventional in the art, and those skilled in the art can select them as needed. No particular limitation is made in this invention, but as an example, styrene-based ion exchange resins, etc., can be used.

[0066] A second aspect of the present invention provides an application of the purification and treatment method for perchlorate wastewater provided in the present invention in the field of perchlorate wastewater treatment.

[0067] The following description, in conjunction with specific embodiments, provides further details.

[0068] Example 1

[0069] Example 1 provides a method for purifying perchlorate wastewater, the steps of which are as follows:

[0070] (1) After the perchlorate wastewater is filtered by sand, activated carbon, PP cotton, ultrafiltration membrane and reverse osmosis, the salt concentration of the wastewater is 15 g / L.

[0071] (2) The wastewater filtered in step (1) is then treated with anaerobic bacteria:

[0072] 1) The selected anaerobic bacteria were perchlorate-reducing bacteria QD19-16.

[0073] 2) Preparation of polylactic acid adhesive:

[0074] ① Select polylactic acid with an average molecular weight of 900. The mass ratio of polylactic acid, lecithin and ethanol is 40:8:1.

[0075] ② Under the condition of stirring speed of 40 rpm, lecithin was added to ethanol, and polylactic acid powder was added in 10 portions. Stirring was continued for 12 minutes to obtain polylactic acid binder.

[0076] 3) Preparation of anaerobic bacteria spray solution:

[0077] ① The mass ratio of anaerobic bacteria, lecithin, and water was selected as 0.23:3:2.

[0078] ② Under the condition of stirring speed of 50 rpm, lecithin was added to water, followed by anaerobic bacteria, and stirring was continued for 10 minutes to obtain anaerobic bacterial spray solution.

[0079] 4) Preparation of anaerobic bacterial molecular sieves:

[0080] ① SBA-15 molecular sieve with an average particle size of 200 μm and an average pore size of 40 nm was selected, and the mass ratio of polylactic acid binder, anaerobic bacteria spray liquid and molecular sieve was 70:25:1.

[0081] ②Immerse the molecular sieve in polylactic acid binder, filter it through a 90-mesh sieve, and dry it at 20°C until it reaches a semi-cured state.

[0082] ③ Spray the anaerobic bacteria spray solution onto the semi-cured polylactic acid binder and dry and cure it at 20°C to obtain the anaerobic bacteria molecular sieve.

[0083] 5) Under the condition of stirring speed of 10 rpm, add 150 g / L of anaerobic molecular sieve to the wastewater after filtration in step (1) and continue stirring for 36 h.

[0084] (3) After anaerobic treatment, the wastewater is filtered by a filter screen, then filtered by ion exchange resin and activated carbon to obtain purified wastewater.

[0085] Example 2

[0086] Example 2 provides a method for purifying perchlorate wastewater, the steps of which are basically the same as those in Example 1, except that:

[0087] In (1), the salt concentration of the filtered wastewater is 5 g / L.

[0088] In (2) of the above, the mass ratio of polylactic acid, polylactic acid, lecithin and ethanol is 50:10:1;

[0089] In step 3), the mass ratio of anaerobic bacteria, lecithin, and water is 0.23:2:1.

[0090] In step 4), the mass ratio of polylactic acid binder, anaerobic bacterial spray, and molecular sieve is 50:20:1.

[0091] In step 5), the amount of anaerobic molecular sieve added is 100 g / L.

[0092] Example 3

[0093] Example 3 provides a method for purifying perchlorate wastewater, the steps of which are basically the same as those in Example 1, except that:

[0094] In (1), the salt concentration of the filtered wastewater is 20 g / L.

[0095] In (2) of the above, the mass ratio of polylactic acid, polylactic acid, lecithin and ethanol is 30:10:1;

[0096] In 3), the mass ratio of anaerobic bacteria, lecithin, and water is 0.23:2:3;

[0097] In step 4), the mass ratio of polylactic acid binder, anaerobic bacterial spray, and molecular sieve is 80:30:1.

[0098] In step 5), the amount of anaerobic molecular sieve added is 200 g / L.

[0099] Example 4

[0100] Example 4 provides a method for purifying perchlorate wastewater, the steps of which are basically the same as those in Example 1, except that:

[0101] In (1), the salt concentration of the filtered wastewater is 20 g / L.

[0102] In (2) of the above, the mass ratio of polylactic acid, polylactic acid, lecithin and ethanol is 30:5:1.

[0103] In 3), the mass ratio of anaerobic bacteria, lecithin, and water is 0.23:3:2.

[0104] In step 4), the mass ratio of polylactic acid binder, anaerobic bacterial spray, and molecular sieve is 75:28:1.

[0105] In step 5), the amount of anaerobic molecular sieve added is 200 g / L.

[0106] Comparative Example 1

[0107] Comparative Example 1 provides a method for purifying perchlorate wastewater, the steps of which are as follows:

[0108] (1) After the perchlorate wastewater is filtered by sand, activated carbon, PP cotton, ultrafiltration membrane and reverse osmosis, the salt concentration of the wastewater is 15 g / L.

[0109] (2) The wastewater is purified by filtration through ion exchange resin and activated carbon.

[0110] To verify the advancement of the purification method for perchlorate wastewater in this invention, the perchlorate content in the purified wastewater of the embodiments and comparative examples was detected by spectrophotometry. The results are shown in Table 1 below.

[0111] Table 1

[0112] Example 1 15 0.19 Example 2 5 0.13 Example 3 20 0.27 Example 4 20 0.35 Comparative Example 1 15 2.01

[0113] Note: In Table 1 above, C1 represents the salt concentration of the wastewater obtained after perchlorate wastewater is filtered through sand, activated carbon, PP cotton, ultrafiltration membrane and reverse osmosis; C2 represents the concentration of perchlorate in the purified wastewater.

[0114] From Table 1 above, we can obtain:

[0115] (1) The purification method for perchlorate wastewater provided in this embodiment of the invention includes a first filtration treatment to remove solid particles, heavy metal ions, and some perchlorate from the perchlorate wastewater, reducing the salinity so as not to affect the activity of anaerobic bacteria; the anaerobic bacteria treatment decomposes perchlorate ions to obtain chloride ions, which are then absorbed by the second filtration treatment for resource recovery. The method is widely applicable to perchlorate wastewater in various fields.

[0116] (2) The perchlorate wastewater purification method provided in the present invention produces wastewater with a perchlorate concentration of less than 0.35 mg / L.

[0117] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for purifying treatment of perchlorate-containing wastewater, characterized by, Includes the following steps: After the perchlorate wastewater undergoes a first filtration treatment, an anaerobic bacteria treatment, and a second filtration treatment, purified wastewater is obtained. In the anaerobic treatment, anaerobic molecular sieves are used to anaerobic treat the perchlorate wastewater. In the anaerobic molecular sieve, the molecular sieve is a mesoporous molecular sieve; The anaerobic molecular sieve has an average particle size of 170μm~250μm. After the first filtration treatment, the salt concentration in the perchlorate wastewater is 5 g / L to 20 g / L. The preparation of the anaerobic molecular sieve includes the following steps: after loading polylactic acid binder onto the surface of the molecular sieve, spraying anaerobic bacterial spray liquid, and drying and solidifying to obtain the anaerobic molecular sieve. The anaerobic spray solution contains anaerobic bacteria, lecithin, and water; The polylactic acid binder contains polylactic acid, lecithin, and ethanol; The step of loading polylactic acid binder onto the surface of a molecular sieve includes: immersing the molecular sieve in the polylactic acid binder, filtering, and drying to a semi-cured state; The preparation of the polylactic acid adhesive liquid includes the following steps: under the condition of stirring speed of 30 rpm to 80 rpm, lecithin is added to ethanol, and polylactic acid powder is added in more than 10 portions, and stirring is continued for 10 min to 15 min to obtain the polylactic acid adhesive liquid. The preparation of the anaerobic bacteria spray solution includes the following steps: under the condition of stirring speed of 50 rpm to 100 rpm, lecithin is added to water, then anaerobic bacteria are added, and stirring is continued for 10 min to 15 min to obtain the anaerobic bacteria spray solution. The anaerobic bacteria are perchlorate-reducing bacteria QD19-16.

2. The method for purifying perchlorate-containing wastewater according to claim 1, characterized by, In the anaerobic bacterial spray solution, the mass ratio of the anaerobic bacteria, the lecithin, and the water is 0.23:2~3:1~3.

3. The method for purifying perchlorate-containing wastewater according to claim 2, characterized by, In the polylactic acid adhesive, the mass ratio of polylactic acid, lecithin and ethanol is 30~50:5~10:

1.

4. The method for purifying perchlorate wastewater according to claim 2 or 3, characterized in that, The polylactic acid has an average molecular weight of 800-1000.

5. The method for purifying perchlorate wastewater according to claim 1, characterized in that, The first filtration process includes at least one of the following: sand filtration, activated carbon filtration, PP cotton filtration, ultrafiltration membrane filtration, and reverse osmosis filtration. And / or, the second filtration process includes screen filtration, and further includes at least one of ion exchange resin filtration and activated carbon filtration.

6. The application of the purification treatment method for perchlorate wastewater as described in any one of claims 1 to 5 in the field of perchlorate wastewater treatment.