CN108640706A - Filtering and adsorbing device and preparation method of flaky porous ceramic membrane - Google Patents

Abstract

The invention discloses a filtration and adsorption device and a method for preparing a sheet-shaped porous ceramic membrane, which relate to the technical field of water treatment. The one-piece filter cup is composed of a liquid storage cup and a separation cup which are integrally formed. An annular boss is designed at the connection between the liquid storage cup and the separation cup, and an O-shaped sealing ring is arranged on the annular boss. A sheet-shaped porous ceramic membrane is placed close to the upper part of the O-shaped sealing ring; the cylindrical limiter is directly placed in the liquid cup, and the bottom ring surface of the cylindrical limiter is pressed against the sheet-like porous ceramic membrane superior. By rationally designing the structure of the filter and adsorption device, the integrated filter and adsorption device has the advantages of simple use, easy replacement, and the like. By rationally designing the preparation method of the filter membrane, the prepared ceramic filter membrane has good adsorption performance, reproducibility and long service life.

Description

A kind of preparation method of filter adsorption device and sheet-like porous ceramic membrane

technical field

The invention relates to the technical field of water treatment, in particular to a filter adsorption device and a preparation method of a sheet-shaped porous ceramic membrane.

Background technique

Suction filtration, also known as decompression filtration and vacuum filtration, mainly uses an air pump to reduce the pressure in the filtration bottle to achieve the purpose of solid-liquid separation. The structure of the existing commonly used suction filtration equipment is shown in Figure 1, and mainly consists of a suction filter bottle 10 and a sand core filter device. The sand core filter device is composed of two parts. The liquid holding part 12 and the filter assembly 11 are detachably installed and fixed by a clip 13 . The top plane of the filter assembly 11 is provided with a sand-type microporous filter membrane 15 . When this suction filtration equipment is in use, at first the bottom of the filter assembly 11 is inserted in the suction filtration bottle 10, then the filter paper 14 of suitable size is cut and placed on the sand microporous filter membrane 15, and then the bottom ring surface of the liquid holding part 12 is used to The filter paper 14 is compressed, and then the clip 13 is installed between the liquid holding part 12 and the filter assembly 11 to achieve fastening. The pressure in the filter assembly 11 is reduced by the connected vacuum pump, so that the solution in the liquid holding part 12 achieves the purpose of solid-liquid separation, the solid is trapped in the liquid holding part 12 , and the liquid enters the suction filter bottle 10 . The above-mentioned commonly used suction filtration equipment mainly has the following disadvantages:

①, no adsorption function

Although a sand-type microporous filter membrane is designed on the filter assembly, this filter membrane is more for the purpose of solid-liquid separation and cannot achieve the function of adsorption and filtration. For example, it cannot absorb and remove organic pollutants such as methylene blue and printing and dyeing. waste water, etc.

② Difficult to clean and non-renewable

Sand microporous membranes are difficult to clean and are not reproducible. It is impossible or difficult to remove the sand-type microporous membrane of the filter assembly for replacement. After a period of use, the filter assembly and the sand-type microporous membrane are replaced together, which leads to high use costs.

③. Complex installation and inconvenient replacement

Before installation, the filter paper needs to be cut to the appropriate size. Then install and fix the liquid holding part and the filter assembly through the clips. After use, it is necessary to manually remove the liquid holding part and filter assembly, which is very cumbersome to handle.

In addition, as the core component of the traditional adsorption separation device - the membrane module has been widely concerned, especially the ceramic membrane, which is popular because of its good adsorption and separation performance. Ceramic membranes, also known as inorganic ceramic membranes, are asymmetric membranes prepared from inorganic ceramic materials through special processes. Ceramic membranes are mainly divided into two types: tubular ceramic membranes and sheet ceramic membranes. The tube wall of the tubular ceramic membrane is densely covered with micropores. Under the action of pressure, the raw material liquid flows in the membrane tube or outside the membrane, small molecular substances (or liquid) pass through the membrane, and macromolecular substances (or solids) are intercepted by the membrane, thereby achieving separation, Concentration, purification and environmental protection purposes. The sheet-like ceramic membrane (or flat ceramic membrane) is densely covered with micropores. According to the different molecular diameters of the permeated substances within a certain range of membrane pore size, the permeability is different. The pressure difference on both sides of the membrane is the driving force, and the membrane is The filter medium, under a certain pressure, when the feed liquid flows through the surface of the membrane, only water, inorganic salts, and small molecular substances are allowed to pass through the membrane, while macromolecular substances such as suspended solids, glue and microorganisms in the water are prevented from passing through. Ceramic membrane has high separation efficiency, stable effect, good chemical stability, acid and alkali resistance, organic solvent resistance, bacteria resistance, high temperature resistance, pollution resistance, high mechanical strength, good regeneration performance, simple separation process, low energy consumption, easy operation and maintenance. With many advantages such as simplicity and long service life, it has been successfully applied in many fields such as food, beverage, plant (drug) deep processing, biomedicine, fermentation, fine chemical industry and so on.

Fly ash is a kind of gray material, which is mainly produced by calcination of inorganic components such as clay minerals, quartz, calcite, pyrite and other minerals in coal. Therefore, the chemical composition of fly ash is mainly Al ₂ O ₃ and SiO ₂ , and there are also CaO, Fe ₂ O ₃ , MgO, Na ₂ O, K ₂ O, SO ₃ and incompletely combusted organic substances. Fly ash particles have a spherical structure and a large number of micropores, high activity, large specific surface area, easy grinding, low calcining temperature when made into products, and energy saving. It is an excellent raw material.

Because Al ₂ O ₃ , zirconia and other materials for making ceramic membranes are relatively expensive, and at the same time, the production of ceramic membranes requires high-temperature sintering, resulting in high production costs and difficult industrialization. Therefore, it is only obtained in high-end fields such as pharmaceuticals, food, and beverages. Preliminary application; however, in the field of wastewater treatment, especially in the field of industrial wastewater treatment, due to the low profit margin of the industry itself and the large daily treatment volume, if ceramic membranes are used for treatment, the high cost has not been put into practical application. In view of the fact that fly ash contains a large amount of Al ₂ O ₃ , SiO ₂ and other substances, if fly ash is used to make ceramic membranes, not only can the fly ash be recycled, but the ceramic membranes made will have potential in many aspects. Value. Therefore, it is of great significance both in terms of environmental protection and in terms of technology. The present invention is just based on this starting point, develops and researches.

Contents of the invention

In view of the above technical problems, the present invention provides a filter adsorption device and a preparation method of a sheet-shaped porous ceramic membrane. In order to achieve the above object, the technical solution adopted in the present invention is: a filter adsorption device, which is composed of a suction filter bottle, an integrated filter cup and a pressing mechanism, and the integrated filter cup is a liquid-holding cup made by integral molding It is composed of a separation cup, the liquid storage cup is placed on the upper part of the separation cup, and the lower part of the separation cup is inserted into the filter bottle; a ring-shaped boss is designed at the connection between the liquid storage cup and the separation cup, and a ring-shaped boss is arranged on the ring-shaped boss. An O-shaped sealing ring, a sheet-shaped porous ceramic membrane is closely attached to the upper part of the O-shaped sealing ring;

The pressing mechanism includes a hollow cylindrical limiter and a set of limiter ropes. The cylindrical limiter is directly placed in the liquid cup, and the bottom ring surface of the cylindrical limiter is pressed against the sheet. On the porous ceramic membrane, the outer diameter of the cylindrical limiting member is not greater than the outer diameter of the sheet-like porous ceramic membrane;

A lower limit hook is processed on the top outer surface of the liquid storage cup, and an upper limit hook is formed on the top outer surface of the cylindrical limiter. The two ends of a set of limit ropes connect the upper limit hook and the lower limit hook. .

As another object of the present invention, the preparation method steps of sheet-like porous ceramic membrane are as follows:

(1), the fly ash retrieved by the power plant is sieved and classified through a 500-mesh vibrating sieve;

(2) The total mass of powder raw materials is designed to be 20g. Put 16g of fly ash, 1.6g of Al ₂ O ₃ , 2g of starch and 0.4g of TiO ₂ into the ball mill tank. The mass ratio of material:ball is 1:2. Add balls for ball milling, the ball milling time is 0.5h;

(3) Put the ball-milled powder into a beaker, add 1.75mL of distilled water and stir for 10min, then pour the mixture into the mold of a molding machine and pressurize to 18MPa, and keep the pressure for a period of time to obtain a green body. Air-dried for 40 hours under natural conditions;

(4) Put the green body into a high-temperature furnace for temperature-programmed sintering, raise it from room temperature 25°C to 100°C at a rate of 1°C/min, keep it warm for 60 minutes, and then raise it to 300°C at a rate of 1°C/min, and keep it warm After 60 minutes, the pore-forming agent starch was fully thermally decomposed to form pores, then raised to 1200°C at a rate of 2°C/min, kept for 30 minutes, and finally lowered to room temperature at a rate of 2°C/min.

Compared with the prior art, the beneficial effects of the present invention are as follows:

1), the present invention sets out from two angles, to overcome the defective that the suction filtration equipment of prior art exists. Firstly, by rationally designing the structure of the filter and adsorption device, the integrated filter and adsorption device has the advantages of simple use and easy replacement. At the same time, the filter membrane, the core component of the filter and adsorption device, is improved. By rationally designing the preparation method of the filter membrane, the prepared ceramic filter membrane has good adsorption performance, is reproducible, and has a long service life.

2) The present invention uses fly ash as the main raw material and starch as the pore-forming agent to increase the porosity and water flux of the porous ceramic membrane; and uses Al ₂ O ₃ and TiO ₂ as the sintering aids. At the same time, the main purpose of adding a certain amount of TiO ₂ is to increase the flexural strength of the porous ceramic membrane; adding a certain amount of Al ₂ O ₃ is to change the ratio of SiO ₂ and Al ₂ O ₃ in the fly ash to form excellent performance after high temperature sintering porous ceramic materials. The main crystal phase of the prepared porous ceramic membrane is the mullite crystal phase, and the porous ceramic membrane with the mullite crystal phase has a higher strength. Generally, the flexural strength of the porous ceramic membrane with the mullite crystal phase as the main crystal phase Up to 1400-1500MPa, suitable for sewage filtration treatment under relatively high pressure.

3), the present invention uses fly ash to develop inorganic porous ceramic membranes, which not only improves the utilization rate of fly ash, but also reduces the preparation cost and raw material tension of inorganic ceramic membranes. After the industrial wastewater and high-temperature waste gas are filtered and adsorbed through the prepared inorganic porous ceramic membrane, the problem of environmental pollution can be alleviated, and a large amount of energy and resources can be saved.

Description of drawings

A filter and adsorption device and a method for preparing a sheet-shaped porous ceramic membrane of the present invention will be further described in detail below in conjunction with the examples and accompanying drawings.

Fig. 1 is the structural schematic diagram of existing commonly used suction filtration equipment.

Fig. 2 is a schematic structural view of the first embodiment of the filter adsorption device of the present invention.

FIG. 3 is a partially enlarged schematic diagram of A in FIG. 2 .

Fig. 4 is a schematic structural view of the second embodiment of the filtration and adsorption device of the present invention.

FIG. 5 is a partially enlarged schematic diagram of the location B in FIG. 4 .

Fig. 6 is the calcining temperature programming curve in the preparation method.

Detailed ways

Example 1

As the first embodiment of the filtration and adsorption device of the present invention, please refer to Fig. 2-3, which mainly consists of a suction filter bottle 10 and an integrated filter cup. The cup 22 and the separation cup 21 are composed, the liquid holding cup 22 is placed on the top of the separation cup 21, and the bottom of the separation cup 21 is inserted into the filter bottle 10, meanwhile, the separation cup 21 is also designed with a suction nozzle connected to the vacuum pump.

Compared with the prior art, the main improvement of the filter adsorption device of the present invention lies in the integrated filter cup, an annular boss 23 is designed at the part where the liquid holding cup 22 and the separation cup 21 are connected, and the annular boss 23 is provided with There is an O-shaped sealing ring 24, and a sheet-shaped porous ceramic membrane 50 is arranged close to the upper part of the O-shaped sealing ring 24.

When using the filtration and adsorption device of this embodiment, first insert the bottom of the integrated filter cup into the suction filtration flask 10, and then place the sheet-like porous ceramic membrane 50 on the O-ring 24 to start the suction filtration operation. The sheet-like porous ceramic membrane 50 can be easily dismantled, cleaned and replaced without replacing other parts of the filter and adsorption device. The filter and adsorption device of this embodiment has the advantages of simple use and easy replacement through the design of an integrated filter cup.

Example 2

As the second embodiment of the filtration and adsorption device of the present invention, please refer to Fig. 4-5, the difference between it and the first embodiment mainly lies in the addition of a pressing mechanism. The pressing mechanism includes a hollow cylindrical stopper 30 and a group of stopper ropes 40. The cylindrical stopper 30 is directly placed in the liquid cup 22, and the bottom ring surface of the cylindrical stopper 30 Pressed on the sheet-shaped porous ceramic membrane 50 , the outer diameter of the cylindrical limiting member 30 is not larger than the outer diameter of the sheet-shaped porous ceramic membrane 50 .

At the same time, a lower limit hook 26 is formed on the top outer surface of the liquid holding cup 22, and an upper limit hook 31 is formed on the top outer surface of the cylindrical limiter 30. The two ends of a set of limit ropes 40 are respectively connected. Upper limit hook 31 and lower limit hook 26.

When the filter adsorption device of this embodiment is in use, first insert the bottom of the integrated filter cup into the suction filter bottle 10, then place the sheet-like porous ceramic membrane 50 on the O-ring 24, and then put it into the cylindrical filter cup. position member 30, and then use the limit rope 40 to press the bottom ring surface of the cylindrical limit member 30 on the sheet-shaped porous ceramic membrane 50, and then the suction filtration operation can be started.

Before the compression mechanism is designed, the sheet-shaped porous ceramic membrane can basically achieve a perfect fit with the O-ring under the action of its gravity and the pressure of the liquid in the liquid cup. The purpose of designing the compression structure is to further reduce the gap between the sheet-like porous ceramic membrane and the O-ring, and minimize the gap as much as possible. This point does not have a great impact on solid-liquid separation. When the filter and adsorption device uses adsorption to separate organic pollutants, in order to improve the effect of adsorption and removal, it is very important to further reduce the gap between the two.

Example 3

The preparation method of sheet-like porous ceramic membrane, the steps are as follows:

(1), the fly ash retrieved by the power plant is sieved and classified through a 500-mesh vibrating sieve;

(2) The total mass of powder raw materials is designed to be 20g. Put 16g of fly ash, 1.6g of Al ₂ O ₃ , 2g of starch and 0.4g of TiO ₂ into the ball mill tank. The mass ratio of material:ball is 1:2. Add balls for ball milling, the ball milling time is 0.5h;

(3) Put the ball-milled powder into a beaker, add 1.75mL of distilled water and stir for 10min, then pour the mixture into the mold of a molding machine and pressurize to 18MPa, and keep the pressure for a period of time to obtain a green body. Air-dried for 40 hours under natural conditions;

(4) Put the green body into a high-temperature furnace for temperature-programmed sintering. Since starch is completely thermally decomposed at 283°C, the green body needs to be kept at this temperature for a holding time. The heating curve of the sintering of the sheet-shaped porous ceramic membrane is as follows As shown in Figure 6, the rate of 1 °C/min is raised from room temperature 25 °C to 100 °C, and the temperature is maintained for 60 minutes. 60min. At this time, the heat preservation is to make the pore-forming agent starch fully thermally decompose to form pores, and then rise to 1200°C at a rate of 2°C/min, and hold the heat for 30min. At this time, the heat preservation is mainly to completely sinter the particles. min rate down to room temperature.

Example 4

The performance advantages of sheet-like porous ceramic membranes are mainly reflected in the following aspects:

1. Porous ceramic membrane has good adsorption performance

1.1 Adsorption of methylene blue solution

1.1.1 Determination of maximum adsorption rate

Prepare a volume of 100 mL of methylene blue solution with a concentration of 10 mg/L; the prepared methylene blue solution is circulated through the adsorption device of Example 2 (loading the sheet-shaped porous ceramic membrane prepared in Example 3, the same below) for adsorption treatment. After a certain number of times, measure the absorbance of the filtrate and compare it with the initial absorbance of the methylene blue solution. Through experiments, it can be obtained that the adsorption and removal rate of the porous ceramic membrane for the first treatment of the methylene blue solution is as high as 90.1%, indicating that the adsorption treatment effect of the porous ceramic membrane is better, and multiple filtration and adsorption treatments are not required. The removal rate increased slowly during the third membrane filtration, and reached a maximum of 93.6% after the fourth membrane filtration.

1.1.2 Determination of maximum adsorption capacity

Several volumes of 100mL methylene blue solutions with the same concentration of 10mg/L were prepared, and were subjected to adsorption treatment by the filtration and adsorption device of Example 2, and the absorbance of the filtrate after each adsorption was measured. After repeated experiments, it can be obtained that as the volume of the same concentration of methylene blue solution in membrane filtration increases, the absorbance of the corresponding filtration solution gradually increases, and the removal rate decreases accordingly. When the total filtration volume of the methylene blue solution with a concentration of 10mg/L reaches 1200mL, the corresponding removal rate is almost unchanged. 800mL.

1.2 Adsorption of printing and dyeing wastewater

In order to further explore the effect of the porous ceramic membrane on the actual printing and dyeing wastewater, and provide a certain reference value for industrial applications, take a small amount of printing and dyeing wastewater and centrifuge to take the supernatant, dilute it by 20 times, and use the filter adsorption device of Example 2 to adsorb it. . The wastewater actually treated in the study was the printing and dyeing wastewater without any treatment from Zhejiang Mizuda Printing and Dyeing Group Co., Ltd. Through experiments, it is obtained that the decolorization rate of the porous ceramic membrane to treat printing and dyeing wastewater diluted 20 times is about 42%, and the COD removal rate is about 31%.

2. Porous ceramic membranes are renewable

The adsorbed porous ceramic membrane was placed in an ethanol solution for ultrasonic oscillation, and the color of the precipitated liquid gradually deepened as time went on. By measuring its absorbance, it can also be found that its absorbance is gradually increasing. After 60 min, the absorbance of the eluate no longer increased. It shows that through certain means (such as ultrasonic vibration in ethanol solution, etc.), the substances adsorbed by the porous ceramic membrane can be re-precipitated, thereby realizing the regeneration and reuse of the porous ceramic membrane.

3. Excellent physical properties

After testing, it can be seen that the average pore diameter of the porous ceramic membrane sample prepared by sintering in Example 3 is 2 μm, the porosity is 41.3%, the flexural strength is 8.96 MPa, the water flux is 1201 L/(m ² ·h·MPa), and the water absorption rate 22.61%, acid resistance is 96.5%, alkali resistance is 95.1%, bulk density is 1.69g/mL, sheet film diameter is 50mm, thickness is 7mm, mass after sintering is 19g, sintering shrinkage rate is 9.1%.

The above content is only an example and description of the concept of the present invention. Those skilled in the art make various modifications or supplements to the described specific embodiments or replace them in similar ways, as long as they do not deviate from the concept of the invention Or beyond the scope defined in the claims, all should belong to the protection scope of the present invention.

Claims (3)

1. A filter adsorption device is characterized in that it is made up of a suction filter bottle (10), an integrated filter cup and a pressing mechanism, and the integrated filter cup is made of an integrally formed liquid-holding cup (22) and a separate cup (21), the liquid holding cup (22) is placed on the top of the separation cup (21), and the bottom of the separation cup (21) is inserted into the suction filter bottle (10); between the liquid holding cup (22) and the separation cup (21 ) is designed with an annular boss (23), an O-ring (24) is arranged on the annular boss (23), and a piece is arranged on the upper part of the O-ring (24). Shaped porous ceramic membrane (50); The pressing mechanism includes a hollow cylindrical limiter (30) and a set of limiter ropes (40), the cylindrical limiter (30) is directly placed in the liquid cup (22), and the cylinder The bottom annulus of shape stopper (30) is pressed on sheet-like porous ceramic membrane (50), and the outer diameter of cylindrical stopper (30) is not greater than the outer diameter of sheet-like porous ceramic membrane (50); A lower limit hook (26) is formed on the top outer peripheral surface of the liquid holding cup (22), an upper limit hook (31) is formed on the top outer peripheral surface of the cylindrical limiter (30), and a set of limit ropes The two ends of (40) are connected with upper limit hook (31) and lower limit hook (26). 2. filter adsorption device as claimed in claim 1, is characterized in that, the preparation method step of described sheet-like porous ceramic membrane is as follows: (1), the fly ash retrieved by the power plant is sieved and classified through a 500-mesh vibrating sieve; (2) The total mass of powder raw materials is designed to be 20g. Put 16g of fly ash, 1.6g of Al ₂ O ₃ , 2g of starch and 0.4g of TiO ₂ into the ball mill tank. The mass ratio of material:ball is 1:2. Add balls for ball milling, the ball milling time is 0.5h; (3) Put the ball-milled powder into a beaker, add 1.75mL of distilled water and stir for 10min, then pour the mixture into the mold of a molding machine and pressurize to 18MPa, and keep the pressure for a period of time to obtain a green body. Air-dried for 40 hours under natural conditions; (4) Put the green body into a high-temperature furnace for temperature-programmed sintering, raise it from room temperature 25°C to 100°C at a rate of 1°C/min, keep it warm for 60 minutes, and then raise it to 300°C at a rate of 1°C/min, and keep it warm After 60 minutes, the pore-forming agent starch was fully thermally decomposed to form pores, then raised to 1200°C at a rate of 2°C/min, kept for 30 minutes, and finally lowered to room temperature at a rate of 2°C/min. 3. The filtration and adsorption device as claimed in claim 2, characterized in that the average pore diameter of the prepared sheet-shaped porous ceramic membrane is 2 μm, the porosity is 41.3%, the flexural strength is 8.96MPa, and the water flux is 1201L/ (m ² ·h·MPa), the water absorption rate is 22.61%, the acid resistance is 96.5%, the alkali resistance is 95.1%, the bulk density is 1.69g/mL, the diameter of the sheet film is 50mm, the thickness is 7mm, after sintering The mass is 19g, and the sintering shrinkage rate is 9.1%.