Catalytic ceramic membrane reaction device and application method thereof

Abstract

The invention discloses a catalytic ceramic membrane reaction device and an application method thereof, a catalytic disc type ceramic membrane is adopted, in a relatively closed reactor cavity, a nano disc type aerator is used for conveying and dispersing an oxidizing agent and adjusting the pressure in the reactor cavity, and the catalytic disc type ceramic membrane and the nano disc type aerator are arranged at an interval; the catalytic disc type ceramic membrane is uniformly mixed with the oxidizing agent in a rotating state, so that the mass transfer distance of the oxidizing agent entering membrane pores after being mixed with reaction feed liquid is shortened, the nano confinement catalytic reaction efficiency and the catalytic degradation efficiency of pollutants are greatly improved, and the pollutants in the wastewater are efficiently removed.

Description

Technical Field

[0001] The present invention relates to the technical field of membrane-confined catalytic deep water treatment, and particularly relates to a catalytic ceramic membrane reaction device and an application method thereof. Background Art

[0002] Ceramic membranes are a kind of porous physical screening materials, and their structures mainly include flat ceramic membranes, tubular ceramic membranes, disk ceramic membranes, etc. Through technological innovation and process improvement, the pore size of ceramic membranes can be adjusted to 0.05 - 5 μm, and they have been widely used in fields such as solid-liquid separation, gas-solid separation, and liquid-liquid separation. In particular, the catalytic ceramic membrane technology developed in recent years loads high-performance catalysts inside the membrane pores, utilizes the nano-confined space of the membrane pores to catalytically activate oxidants to generate reactive oxygen species (ROS), confines ROS and target pollutants in the nano-space, further shortens the mass transfer distance, increases the reaction efficiency, and realizes the efficient removal of pollutants.

[0003] Most of the existing catalytic ceramic membrane devices adopt a method of concentrating the catalytic ceramic membrane and the oxidant in the same open reaction pool, and during the mixing process of the oxidant and water, through the membrane pores, the nano-confined catalytic degradation of pollutants is realized. However, this method is limited by the degree of uniformity of the mixing of the oxidant and water. Especially for gaseous oxidants (such as ozone), the solubility of ozone bubbled out by the aeration head in the open pool is relatively low in water, and at the same time, large bubbles are gradually formed and float to the water surface and burst as time goes by, resulting in the problems of a large ozone dosage and low utilization efficiency, greatly limiting the water treatment efficiency of membrane-confined catalysis and also increasing the water treatment cost.

[0004] In order to solve the problem of low utilization efficiency of gaseous oxidants, the prior art uses solid (persulfate) or liquid oxidants (hydrogen peroxide, peracetic acid, etc.), dissolves these oxidants in water to form a pre-prepared solution with a relatively high concentration, and during the catalytic reaction process, the pre-prepared solution is mixed with the target pollutant solution, and the nano-confined catalytic reaction is carried out through the membrane pores of the catalytic ceramic membrane to degrade pollutants. Although this method can improve the utilization efficiency of the oxidant, due to the mixing process of the pre-prepared solution and the target pollutant solution being a concentration equilibrium process under static conditions, the mixing rate is slow, and the time for the mixed solution to pass through the membrane pores is mostly in the millisecond level. It is difficult to ensure the uniform mixing of the oxidant and the target pollutant solution before the catalytic reaction, which severely limits the membrane pore nano-confined catalytic reaction efficiency and the pollutant removal efficiency. Summary of the Invention

[0005] The object of the present invention is to overcome the deficiencies of the prior art and provide a catalytic ceramic membrane reaction device. By using a catalytic disc ceramic membrane, in a relatively enclosed reactor cavity, a nano-disc aerator is used to transport and disperse the oxidant and adjust the pressure in the reactor cavity, so that the catalytic disc ceramic membrane is uniformly mixed with the oxidant in a rotating state, thereby efficiently removing pollutants in wastewater. Another object of the present invention is to provide an application method of the above catalytic ceramic membrane reaction device.

[0006] The object of the present invention is achieved by the following technical solutions:

[0007] A catalytic ceramic membrane reaction device provided by the present invention includes a reactor cavity, a catalytic disc ceramic membrane, a nano-disc aerator, a hollow tube, a variable-speed motor, and a rotating shaft; the reactor cavity is a closed container provided with a feed liquid inlet; the three catalytic disc ceramic membranes are distributed in a triangle to form a catalytic ceramic membrane module; the nano-disc aerator is two or more, arranged in parallel in the reactor cavity; the catalytic ceramic membrane module is arranged between two adjacent nano-disc aerators, and the nano-disc aerator corresponds to the middle of the triangular area of the catalytic ceramic membrane module; one end of the hollow tube is connected to the nano-disc aerator, and the other end is the inlet of the oxidant; the variable-speed motor drives the catalytic disc ceramic membrane to rotate through the rotating shaft; and the rotating shaft is hollow and serves as a permeate channel, one end of which is connected to the permeate discharge port in the middle of the catalytic disc ceramic membrane, and the other end is located outside the reactor cavity and is provided with a permeate discharge port.

[0008] Further, in the reaction device of the present invention, the reactor cavity is a cylinder with a diameter of 450 - 900 mm and a length of 150 - 800 mm; the nano-disc aerator is a disc ceramic membrane without catalytic function; for the catalytic disc ceramic membrane and the nano-disc aerator, the diameter of the support is 200 - 400 mm, the average pore diameter of the separation membrane layer is 50 - 200 nm, and the thickness is 20 - 50 μm.

[0009] In the above solution, the catalyst component in the catalytic disc ceramic membrane of the present invention accounts for 0.2 - 3 wt% of the matrix.

[0010] Another object of the present invention is achieved by the following technical solutions:

[0011] For the application method of the above catalytic ceramic membrane reaction device provided by the present invention, the pollutant concentration of the feed liquid is 0.1 - 20 mg / L; the gas oxidant is ozone, and its dosage is 0.5 - 10 mg / L; the liquid oxidants are persulfate, hydrogen peroxide, and peracetic acid, and their concentration is 0.2 - 2.0 mM; the membrane flux is 80 - 120 LMH, and it reacts continuously for more than 5 h at a rotation speed of 50 - 250 r / min, and the removal efficiency of pollutants in the permeate is 95 - 100%.

[0012] The present invention has the following beneficial effects:

[0013] (1) By utilizing the rotation of the catalytic disk-type ceramic membrane in the present invention, the feed liquid is promoted to form a turbulent flow, thereby improving the degree of uniform mixing of the oxidant and the feed liquid. At the same time, the nano-disk aerators are evenly distributed on both sides of a catalytic ceramic membrane unit, shortening the mixing distance between the oxidant and the feed liquid, and greatly improving the utilization efficiency of the oxidant.

[0014] (2) In the present invention, the catalytic disk-type ceramic membrane and the nano-disk aerators are concentrated in a relatively closed reaction cavity. By adjusting the volume of the inlet and outlet feed liquids, the pressure in the reaction cavity is regulated, improving the solubility of the oxidant, especially the gaseous oxidant, in water. The nano-disk aerators and the catalytic disk-type ceramic membrane are distributed at intervals, shortening the mass transfer distance from the mixture of the oxidant and the reaction feed liquid into the membrane pores, and greatly improving the nano-confined catalytic reaction efficiency and the catalytic degradation efficiency of pollutants.

[0015] (3) The reaction device of the present invention can achieve automatic control, is suitable for both gaseous oxidants and liquid oxidants, can automatically adjust the mixing ratio of the oxidant and the feed liquid, and effectively promotes the large-scale application of the catalytic ceramic membrane. Description of the Drawings

[0016] The present invention will be further described in detail below in conjunction with the embodiments and the drawings:

[0017] Figure 1 is a schematic structural diagram of the catalytic ceramic membrane reaction device according to Embodiment 1 of the present invention;

[0018] Figure 2 is Figure 1 a schematic diagram showing the arrangement of the catalytic ceramic membrane module and the nano-disk aerator in the illustrated embodiment.

[0019] In the figure: reactor cavity 1, feed liquid inlet 1a,, catalytic disk-type ceramic membrane 2, nano-disk aerator 3, hollow tube 4, variable-speed motor 5, rotating shaft 6, permeate discharge port 6a. Detailed Embodiments

[0020] Embodiment 1:

[0021] Figure 1 、 Figure 2 As shown in

[0022] As Figure 1 shown, the reactor cavity 1 is a closed container provided with a feed liquid inlet 1a. Three catalytic disk-type ceramic membranes 2 are distributed in a triangular shape to form a catalytic ceramic membrane module (seeFigure 2 );The nano-disk aerator 3 is five (a disk-type ceramic membrane without catalytic function), and is arranged in parallel in the reactor cavity 1; the catalytic ceramic membrane module is three and is respectively arranged between two adjacent nano-disk aerators 3, and the nano-disk aerator 3 corresponds to the middle of the triangular area of the catalytic ceramic membrane module (see Figure 2 ). One end of the hollow tube 4 is connected to the nano-disk aerator 3, and the other end is the inlet of the oxidant. The variable-speed motor 5 drives the rotation of the catalytic disk-type ceramic membrane 2 through the rotating shaft 6; and the rotating shaft 6 is hollow and serves as a permeate channel, one end of which is connected to the permeate discharge port in the middle of the catalytic disk-type ceramic membrane 2, and the other end is located outside the reactor cavity 1 and is provided with a permeate discharge port 6a.

[0023] In the catalytic ceramic membrane reaction device of this embodiment, the reaction cavity 1 is a cylinder with a diameter of 500 mm and a length of 400 mm. For the catalytic disk-type ceramic membrane 2 and the nano-disk aerator 3, the thickness of the support body is 2.5 mm and the diameter is 200 mm, and the average pore diameter of the separation membrane layer is 100 nm and the thickness is 30 μm. The catalyst component in the catalytic disk-type ceramic membrane 2 accounts for 1.0 wt% of the matrix.

[0024] Its application method is as follows: the feed liquid is sulfamethoxazole with a concentration of 20 mg / L; the dosage of the gas oxidant ozone is 6 mg / L; the membrane flux is 80 LMH, and it reacts continuously for 12 h at a rotation speed of 150 r / min, and the removal efficiency of sulfamethoxazole in the permeate is 98.5%.

[0025] Example 2:

[0026] In the catalytic ceramic membrane reaction device of this embodiment, the difference from Example 1 is that: the nano-disk aerator 3 is three, and the catalytic ceramic membrane module is two; the reaction cavity 1 is a cylinder with a diameter of 750 mm and a length of 300 mm; for the catalytic disk-type ceramic membrane 2 and the nano-disk aerator 3, the diameter of the support body is 374 mm, the average pore diameter of the separation membrane layer is 150 nm, and the membrane layer thickness is 40 μm. The catalyst component in the catalytic disk-type ceramic membrane 2 accounts for 0.65 wt% of the matrix.

[0027] Its application method is as follows: the feed liquid is carbamazepine with a concentration of 10 mg / L; the concentration of the liquid oxidant hydrogen peroxide is 1.5 mM; the membrane flux is 100 LMH, and it reacts continuously for 10 h at a rotation speed of 80 r / min, and the removal efficiency of carbamazepine in the permeate is 100%.

[0028] The preparation method of the catalytic disk-type ceramic membrane 2 in the embodiment of the present invention is as follows:

[0029] (1) Preparation of the disk-type ceramic membrane support

[0030] Sieve and mix 85 wt% of alumina powder, 13 wt% of aluminum sol with a concentration of 1.5 mol / L, and 2 wt% of hydroxypropyl methylcellulose to obtain dry-pressed powder; adopt the semi-dry pressing forming method, form at a pressure of 12 MPa, and the pressure holding time is 20 s. After demolding, obtain the green body Ⅰ of the disc-shaped ceramic membrane support; adopt the same process to add ribs (permeate flux) into the mold during the dry pressing process to make the inside of the disc-shaped ceramic membrane support have a curved pit, and obtain the green body Ⅱ of the disc-shaped ceramic membrane support; align and paste the green bodies Ⅰ and Ⅱ of the disc-shaped ceramic membrane support (the binder is a viscous slurry formed by adding 42% water to the above dry-pressed powder), and after drying and calcining at a temperature of 1350 °C for 2 h of heat preservation, obtain the disc-shaped ceramic membrane support;

[0031] (2) Preparation of the separation membrane layer

[0032] Adopt the dip-coating method to prepare the separation membrane layer on the surface of the disc-shaped ceramic membrane support. After drying at a temperature of 90 °C, calcine at 1200 °C and keep the temperature for 2 h to obtain a disc-shaped ceramic membrane with a separation membrane layer, and its pore size is 50 - 200 nm;

[0033] (3) Preparation of the catalytic disc-shaped ceramic membrane

[0034] Immerse the above disc-shaped ceramic membrane with a separation membrane layer in a metal nitrate solution with a concentration of 0.02 - 1.5 mol / L. Adopt the pumping and pressing method to make the ceramic membrane fully saturated in the solution, then take it out and dry it in vacuum (the vacuum degree is 0.8 Mpa and the temperature is 90 °C). Place the completely dried ceramic membrane loaded with the metal precursor in a muffle furnace and calcine it at a temperature of 550 °C for 3 - 6 h to obtain the catalytic disc-shaped ceramic membrane.

[0035] The above nitrate can be one or a combination of iron nitrate (Fe(NO3)3·9H2O), cobalt nitrate (Co(NO3)2·6H2O), nickel nitrate Ni(NO3)2, manganese nitrate (Mn(NO3)2·6H2O), silver nitrate (AgNO3), copper nitrate (Cu(NO3)2).

[0036] The nano disc-shaped aerator 3 in the embodiment of the present invention is the disc-shaped ceramic membrane with a separation membrane layer obtained in step (2) of the preparation method of the above catalytic disc-shaped ceramic membrane 2, that is, the disc-shaped ceramic membrane without catalytic function.

Claims

1. A catalytic ceramic membrane reaction device, characterized in that: It includes a reactor cavity (1), a catalytic disk ceramic membrane (2), a nano disk aerator (3), a hollow tube (4), a variable-speed motor (5), and a rotating shaft (6); the reactor cavity (1) is a closed container provided with a feed liquid inlet (1a); the three catalytic disk ceramic membranes (2) are distributed in a triangle to form a catalytic ceramic membrane module; the nano disk aerators (3) are two or more, arranged in parallel in the reactor cavity (1); the catalytic ceramic membrane module is arranged between two adjacent nano disk aerators (3), and the nano disk aerator (3) corresponds to the middle of the triangular area of the catalytic ceramic membrane module; one end of the hollow tube (4) is connected to the nano disk aerator (3), and the other end is the inlet of the oxidant; the variable-speed motor (5) drives the rotation of the catalytic disk ceramic membrane (2) through the rotating shaft (6); and the rotating shaft (6) is hollow and serves as a permeate channel, one end of which is connected to the permeate discharge port in the middle of the catalytic disk ceramic membrane (2), and the other end is located outside the reactor cavity (1) and is provided with a permeate discharge port (6a).

2. The catalytic ceramic membrane reaction device according to claim 1, characterized in that: The reactor cavity (1) is a cylinder with a diameter of 450 - 900 mm and a length of 150 - 800 mm; the nano disk aerator (3) is a disk ceramic membrane without catalytic function; for the catalytic disk ceramic membrane (2) and the nano disk aerator (3), the diameter of the support body is 200 - 400 mm, and the average pore diameter of the separation membrane layer is 50 - 200 nm and the thickness is 20 - 50 μm.

3. The catalytic ceramic membrane reaction device according to claim 1, wherein: The catalyst component in the catalytic disk ceramic membrane (2) accounts for 0.2 - 3 wt% of the matrix.

4. The application method of the catalytic ceramic membrane reaction device according to any one of claims 1 to 3, characterized in that: The pollutant concentration of the feed liquid is 0.1 - 20 mg / L; the gas oxidant is ozone, and its dosage is 0.5 - 10 mg / L; the liquid oxidants are peroxymonosulfate, hydrogen peroxide, and peracetic acid, and their concentration is 0.2 - 2.0 mM; the membrane flux is 80 - 120 LMH, continuously reacting for more than 5 h at a rotation speed of 50 - 250 r / min, and the removal efficiency of pollutants in the permeate is 95 - 100%.

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