CN115745293B - Catalytic reduction dechlorination device containing load type PVDF membrane - Google Patents

Abstract

The invention relates to a catalytic reduction dechlorination device containing a loaded PVDF membrane, which comprises a catalytic reduction area, a mixed reaction area and a precipitation area connected in sequence. The top of the catalytic reduction area is provided with a water inlet and a water distributor connected to each other. A first packing layer is provided below the water distributor for treating sewage; Inlet, sloping plate area and mud discharge outlet, the sewage is separated from mud and water in the sedimentation area to obtain produced water.

Description

A catalytic reduction dechlorination device containing a loaded PVDF membrane

technical field

The invention belongs to the technical field of chlorine-containing organic wastewater treatment, and in particular relates to a catalytic reduction dechlorination device containing a loaded PVDF membrane.

Background technique

Wastewater discharged from industries such as pesticides, dyes, plastics, synthetic rubber, chemicals, and chemical fibers contains a large amount of chlorinated organic compounds. Chlorinated organic compounds are hydrophobic, difficult to be biodegraded, degrade slowly under natural conditions, and will continue to accumulate in the environment and biosphere, and have become one of the most common pollutants in soil and surface water systems. The vast majority of chlorinated organic compounds have the characteristics of high toxicity, refractory degradation, and bioaccumulation, and have carcinogenic, teratogenic, and mutagenic effects. The entry of chlorinated organic substances into the environment not only directly damages the ecological environment, but also causes harm to humans and other organisms in the ecological environment.

The treatment methods of chlorinated organics mainly include physical methods: only the transfer of chlorinated organics can not be achieved, and it is difficult to meet the discharge standards; biological methods: chlorinated organics are foreign compounds, which are difficult for microorganisms to digest and degrade under normal circumstances, which is very likely to cause microbial poisoning; chemical methods: mainly include oxidation and reduction methods. Oxidation methods include incineration, wet oxidation, photocatalytic oxidation and ozone oxidation. Oxidation method and zero-valent iron reduction method, these methods also have problems such as high energy consumption, harsh use conditions, and high cost for large-scale application.

Contents of the invention

In order to solve one of the above-mentioned problems, the present invention provides a catalytic reduction dechlorination device containing a loaded PVDF membrane. The catalytic reduction zone and the mixed reaction zone of the device are all provided with packing layers, and the packing layers are PVDF films loaded with nano-palladium-iron bimetallic particles. dechlorination efficiency. The device is suitable for the treatment of acid, alkali and neutral chlorine-containing wastewater, solves the problem of secondary pollution during the treatment of chlorinated organic matter, has low cost, and is convenient for popularization and application.

The catalytic reduction dechlorination device includes a sequentially connected catalytic reduction zone, a mixed reaction zone and a precipitation zone. The top of the catalytic reduction zone is provided with an interconnected water inlet and a water distributor, and a first packing layer is provided below the water distributor for treating sewage;

The bottom of the mixed reaction zone is provided with an aeration device, the middle part is provided with a second packing layer, and the top is connected with a dosing device for coagulation reaction; both the first packing layer and the second packing layer are equipped with loaded PVDF membranes;

The settling area includes a water production port, an inclined plate area and a mud discharge port from top to bottom, and the sewage is separated from mud and water in the settling area to obtain produced water.

Optionally, the first packing layer includes several first membrane modules arranged horizontally, each first membrane module is wavy and placed vertically, that is, the first membrane module includes several inclined first membranes and second membranes, the first membranes and the second membranes are alternately arranged, and the angles between all the upper and lower adjacent first membranes and second membranes are in the range of 60-150°, which can be the same or different, and can be changed in real time.

Optionally, the area of the first packing layer is provided with a first supporting frame, the first supporting frame includes several groups of vertically arranged first brackets parallel to each other, each group of first brackets is arranged horizontally, and includes a plurality of first positioning rods parallel to each other and two first supporting rods at both ends of the first positioning rods, the first positioning rods and the first supporting rods are at the same level, the two first supporting rods are parallel to each other, the first positioning rods are perpendicular to the first supporting rods, that is, several "I" shapes are formed; the two ends of the first supporting rods are connected to the two side walls of the catalytic reduction zone;

The upper and lower sides of the first diaphragm or the second diaphragm are respectively fixed on the first positioning rods of the two groups of first brackets adjacent up and down, and the upper and lower first positioning rods connected to the same first diaphragm or second diaphragm are not on the same vertical line, so as to ensure that the first diaphragm or the second diaphragm is arranged obliquely.

In order to make the included angle between the first membrane and the second membrane variable, further optionally, a single number of first brackets of the first support frame is movable, or a plurality of first brackets are movable. Taking the movable first support in odd number and the fixed first support in plural as an example, slide rails are provided at the positions corresponding to the first support rods on both side walls of the catalytic reduction zone, that is, two vertical parallel slide rails are provided on one side wall, and the two ends of all the first support rods are clamped in the corresponding slide rails. winding;

The first supporting rod of the odd-numbered first bracket is a sleeve structure, including an inner tube and an outer tube. Both ends of the first positioning rod are fixedly connected to the corresponding outer tube, and both ends of the inner tube are clamped in the slide rail.

Optionally, the catalytic reduction zone is also provided with a circulation port, the circulation port is located below the packing layer, and is connected to the water inlet of the catalytic reduction zone through a circulation pump, and is used to return part of the sewage treated by the loaded PVDF membrane to adjust the state of the water in the catalytic reduction zone;

The water outlet of the catalytic reduction zone is located at the bottom of the catalytic reduction zone and communicates with the catalytic reduction zone and the mixed reaction zone, and the sewage treated in the catalytic reduction zone is input into the mixed reaction zone.

Optionally, the mixing reaction zone is connected to an external dosing device through a dosing pipe, the dosing device includes a dosing pipe and a dosing pump, the dosing pipe is connected to the dosing pipe through the dosing pump, and is used to input coagulant or flocculant into the mixed reaction zone, and fully react under the agitation of the aeration device;

The water outlet of the mixed reaction zone is set on the top of the mixed reaction zone, and communicates with the mixed reaction zone and the sedimentation zone, and the sewage treated in the mixed reaction zone is input into the sedimentation zone.

Optionally, the second packing layer includes several second membrane modules arranged horizontally. The structure of the second membrane module is the same as that of the first membrane module. The difference is that the angles between all the upper and lower adjacent third diaphragms and fourth diaphragms are in the range of 60-180°, which can be the same or different, and can be changed in real time, that is, the second membrane modules can be wavy or straight at certain moments.

The second packing layer area is provided with a second support frame, the structure of the second support frame is the same as that of the first support frame, the difference is that the up and down movement range of the second bracket of the second support frame and the left and right movement range of the outer tube of the second support rod are larger, so that the second membrane module can be changed from a wave shape to a straight line shape.

The loaded PVDF membrane of the present invention has loaded nano-palladium and nano-iron particles, and the preparation method is as follows:

(1) Configure KOH solution, then dissolve KMnO ₄ to obtain KMnO ₄ -KOH solution; configure H ₂ SO ₄ solution, then dissolve NaHSO ₃ to obtain NaHSO ₃ -H ₂ SO ₄ solution; configure KOH solution, then dissolve KBH ₄ to obtain KBH ₄ -KOH solution; configure ethanol solution, and then dissolve Pd(O ₂ CCH ₃ ) ₂ to obtain Pd(O ₂ CCH ₃ ) ₂ -ethanol solution;

(2) Wash the PVDF membrane with deionized water, soak it in KMnO ₄ -KOH solution, and carry out the alkali elution chlorine reaction to obtain the intermediate membrane I;

(3) Wash the intermediate membrane I with deionized water, soak it in NaHSO ₃ —H ₂ SO ₄ solution, and carry out hydrophilic modification to obtain a modified PVDF membrane;

(4) Immerse the modified PVDF membrane in FeSO ₄ solution, and then vacuum dry to obtain a PVDF membrane loaded with Fe ²⁺ ; immerse the PVDF membrane loaded with Fe ²⁺ in KBH ₄ -KOH solution for redox reaction to obtain a PVDF membrane loaded with zero-valent iron;

(5) Immerse the PVDF membrane loaded with zero-valent iron in a Pd(O ₂ CCH ₃ ) ₂ -ethanol solution for chemical deposition to obtain the loaded PVDF membrane.

Optionally, in step (1), the mass concentration of the KOH solution is 16-20%, and the mass concentration of KMnO ₄ in the KMnO ₄ -KOH solution is 8-10%;

The mass concentration _{of H2SO4} solution is 40-45%, and the mass concentration _{of NaHSO3} in _NaHSO3 - _H2SO4 solution is 18-20%;

The mass concentration of KOH solution is 15-20%, and the mass concentration of KBH ₄ in KBH ₄ -KOH solution is 11-15%;

The concentration of the ethanol solution is 70-75wt%, and the mass concentration of Pd(O ₂ CCH ₃ ) ₂ in the Pd(O ₂ CCH ₃ ) ₂ -ethanol solution is 10%.

Optionally, in step (2), the temperature of the alkali elution chlorine reaction is 18-20°C, and the time is 1-2h; PVDF molecules are in the strong alkali and strong oxidation environment of the KMnO ₄ -KOH solution, part of the HF is removed and double bonds are formed, and the membrane body turns from white to brown. The PVDF membrane in step (2) can be prepared, and finished product can also be purchased.

Optionally, in step (3), the temperature of the hydrophilic modification is 20-28°C, and the time is 4-6h; under acidic conditions, the double bond on the intermediate membrane I undergoes a nucleophilic addition reaction to generate polyols, and a hydrophilic group—hydroxyl (-OH) is generated on the membrane, making the PVDF membrane hydrophilic.

Optionally, in step (4), the modified PVDF membrane is immersed in FeSO ₄ solution for 15-20min, the mass concentration of FeSO ₄ solution is 10-13%, and then placed in a drying oven at 115°C for 2-3h in vacuum;

The PVDF membrane loaded with Fe ²⁺ is immersed in the KBH ₄ -KOH solution for 15-20min, and the newly formed zero-valent iron particles are easily oxidized by oxygen in the air. Therefore, after cleaning the PVDF membrane loaded with zero-valent iron with absolute ethanol, it is quickly put into absolute ethanol for preservation.

Optionally, in step (5), the PVDF membrane loaded with zero-valent iron is immersed in Pd(O2CCH3)2-ethanol solution for 10-15min, and nano-palladium particles are loaded by chemical deposition, and the specific reaction is Pd ²⁺ +Fe→Pd↓+Fe ²⁺ .

In the invention, after the PVDF membrane is hydrophilically modified, it is easily wetted by water, which is beneficial for loading nanoparticles. The sewage passes through the packing layer from top to bottom, and the chlorinated organic matter in the sewage reacts with the nano-palladium/iron in the loaded PVDF membrane to generate inorganic chlorine, and the zero-valent iron on the loaded PVDF membrane is partially oxidized to Fe ²⁺ , and enters the sewage. Then, the sewage enters the mixed reaction area. Under the action of aeration, the oxygen in the air oxidizes Fe ²⁺ to Fe ³⁺ , and the Fe ³⁺ coagulates with polyacrylamide (PAM) to form flocs. The flocculated water enters the sedimentation area, passes through the inclined plate, and the flocs settle to the bottom area to form sludge, which is discharged through the sludge discharge pump.

Description of drawings

Fig. 1 is a kind of overall structure schematic diagram of the catalytic reduction dechlorination device that contains load-type PVDF film;

Fig. 2 is the structural representation of the first filler layer;

Fig. 3 is the schematic diagram of the three-dimensional structure of the first packing layer;

Fig. 4 is a schematic diagram of the sliding rail of the first packing layer.

In the drawings, 1-water distributor, 2-first packing layer, 3-aeration device, 4-second packing layer, 5-water production port, 6-sloping plate area, 7-sludge discharge port, 8-first membrane module, 9-first diaphragm, 10-second diaphragm, 11-first bracket, 12-first positioning rod, 13-first support rod, 14-sliding rail, 15-inner pipe, 16-outer pipe, 17-dosing pipe.

Detailed ways

The present embodiment provides a catalytic reduction dechlorination device containing a loaded PVDF membrane, as shown in Figures 1-4, comprising a sequentially connected catalytic reduction zone, a mixed reaction zone and a precipitation zone, the top of the catalytic reduction zone is provided with an interconnected water inlet and a water distributor 1, and a first packing layer 2 is provided below the water distributor 1 for treating sewage;

The bottom of the mixed reaction zone is provided with an aeration device 3, the middle part is provided with a second packing layer 4, and the top is connected with a dosing device for coagulation reaction; both the first packing layer 2 and the second packing layer 4 are equipped with loaded PVDF membranes;

The settling area includes a water production port 5, an inclined plate area 6 and a mud discharge port 7 from top to bottom, and the sewage is separated from mud and water in the settling area to obtain produced water.

Optionally, the first packing layer 2 includes several horizontally arranged first membrane modules 8, each first membrane module 8 is wavy and vertically placed, that is, the first membrane module 8 includes several inclined first diaphragms 9 and second diaphragms 10, the first diaphragms 9 and the second diaphragms 10 are arranged alternately, and the angles between all the first and second diaphragms 9 and 10 adjacent up and down are in the range of 60-150°, which can be the same or different, and can be changed in real time.

Optionally, the area of the first packing layer 2 is provided with a first support frame, the first support frame includes several groups of first brackets 11 arranged vertically and parallel to each other, each group of first brackets 11 is arranged horizontally, and includes several first positioning bars 12 parallel to each other and two first support bars 13 at both ends of the first positioning bar 12, the first positioning bars 12 and the first support bars 13 are at the same level, the two first support bars 13 are parallel to each other, and the first positioning bars 12 are perpendicular to the first support bars 13, that is, several "I" shapes are formed; the first support bars The two ends of 13 are connected to the two side walls of the catalytic reduction zone;

The upper and lower sides of the first diaphragm 9 or the second diaphragm 10 are respectively fixed on the first positioning rods 12 of two groups of first brackets 11 adjacent up and down, and the upper and lower first positioning rods 12 connected to the same first diaphragm 9 or second diaphragm 10 are not on the same vertical line, so as to ensure that the first diaphragm 9 or the second diaphragm 10 is arranged obliquely. The bottom edge of the first membrane 9 and the top edge of the second membrane 10 adjacent up and down of the same first membrane module 8 can be fixed on the same first positioning rod 12 .

Since the first membrane module 8 is wave-shaped, that is, has crests and troughs, when several first membrane modules 8 are horizontally arranged at a certain interval, the crests and troughs of the left and right adjacent first membrane modules 8 are close to each other, that is, the crest on the left bulges into the crest on the right, and the trough on the right sinks into the trough on the left.

In order to make the included angle between the first diaphragm 9 and the second diaphragm 10 changeable, it is further optional that the singular first brackets 11 of the first supporting frame are movable, or the plurality of first brackets 11 are movable, and the first membrane module 8 of the present invention has a wave-shaped structure, and it is not necessary to move all the first brackets 11, and the inclination angle of the diaphragm can be changed only by moving the top or bottom edge of the diaphragm.

Taking the movable first support 11 in odd number and the fixing of first support 11 in plurality as an example, slide rails 14 are provided on the two side wall surfaces of the catalytic reduction zone corresponding to the first support rods 13, that is, two vertical parallel slide rails 14 are arranged on one side wall surface, and the two ends of all first support rods 13 are clamped in the corresponding slide rails 14. It is fixed in the slide rail 14, and plays a role of limiting the upper and lower first support rods 13, preventing the upper and lower diaphragms from overlapping and winding;

The first supporting rod 13 of the singular first bracket 11 is a sleeve structure, including an inner tube 15 and an outer tube 16.

For example, when the angle between the first pair of first diaphragm 9 and the second diaphragm 10 needs to be changed, the second first support 11 is fixed, and the first support rod 13 of the first first support 11 moves downward on the slide rail 14, while the outer tube 16 moves to the left, and the angle between the first diaphragm 9 and the second diaphragm 10 becomes smaller; The movement on 14 can be controlled by a driving device (such as a hydraulic cylinder) outside the catalytic reduction zone, and the movement of the casing can be provided with a push-pull device on the side wall to push the outer pipe 16 to move.

The water distributor 1 of the present invention can use the conventional water distributor 1 on the market. When the catalytic reduction area is in normal operation, the liquid level of the sewage to be treated is higher than the top surface of the first packing layer 2, and the sewage passes through the first packing area from top to bottom, and the organic chlorine in the sewage fully contacts with the surface of the membrane and the palladium-iron catalyst loaded therein to degrade. The plurality of stacked wave-shaped first membrane modules 8 of the present invention can increase the accessible membrane area, at the same time disturb the water flow, and promote the contact between the sewage and the membrane surface. The wavy included angle of the first membrane module 8 is adjustable, so as to adjust the water flow state inside the first packing layer 2 according to the water inlet state, such as adjusting the water flow velocity and direction, so as to improve the treatment efficiency; in addition, real-time adjustment during operation helps to remove the sludge or solid impurities accumulated in the membrane gap by means of the change of the water flow itself, so as to clean the first packing layer 2. Because the diaphragm is inclined, the distance between the upper and lower first brackets 11 and the horizontal distance of the first positioning rod 12 on the top and bottom of the same diaphragm need to be changed to ensure that the diaphragm is always straight and not bent. The present invention adopts a relatively simple structure and moves the fewest parts to simplify the control as much as possible.

In the present invention, the first membrane module 8 is designed to be stacked in a wavy shape, so that sewage can flow down along both sides of the membrane, and the catalysts loaded on the two layers of the membrane can be fully utilized. Concrete, sewage falls on the upper surface of the first membrane 9 first, and flows down along this surface, and in the process of flowing down, part sewage may infiltrate into the lower surface of the first membrane 9 through the membrane hole, and flow down along this surface, the sewage on the lower surface of the first membrane 9 may drop to the upper surface of the first membrane 9 of the adjacent first membrane assembly 8 (because the crest of the adjacent first membrane assembly 8 bulges into the wave crest of the first membrane assembly 8, the two parts are in an up-down relationship), and so on, the upper surface, the lower surface and the membrane All the supported catalysts in the pore channels can be utilized, which improves the utilization of membrane materials.

Optionally, the catalytic reduction zone is also provided with a circulation port, the circulation port is located below the packing layer, and is connected to the water inlet of the catalytic reduction zone through a circulation pump, and is used to return part of the sewage treated by the loaded PVDF membrane to adjust the state of the water in the catalytic reduction zone;

The water outlet of the catalytic reduction zone is located at the bottom of the catalytic reduction zone and communicates with the catalytic reduction zone and the mixed reaction zone, and the sewage treated in the catalytic reduction zone is input into the mixed reaction zone.

Optionally, the mixed reaction zone is connected to an external dosing device through a dosing pipe 17, the dosing device includes a dosing pipe 17 and a dosing pump, the dosing pipe 17 is connected to the dosing pipe 17 through the dosing pump, and is used to input coagulant or flocculant into the mixed reaction zone, and fully react under the agitation of the aeration device 3;

The water outlet of the mixed reaction zone is set on the top of the mixed reaction zone, and communicates with the mixed reaction zone and the sedimentation zone, and the sewage treated in the mixed reaction zone is input into the sedimentation zone.

Optionally, the second packing layer 4 includes several second membrane modules arranged horizontally. The structure of the second membrane module is the same as that of the first membrane module 8. The difference is that the angles between all the upper and lower adjacent third diaphragms and fourth diaphragms are in the range of 60-180°, which can be the same or different, and can be changed in real time, that is, the second membrane modules can be wavy or straight at certain moments.

The second packing layer 4 area is provided with a second support frame, the structure of the second support frame is the same as that of the first support frame, the difference is that the range of up and down movement of the second support of the second support frame and the left and right movement range of the outer tube 16 of the second support rod are larger, so that the second membrane module can be changed from a wave shape to a straight line.

Specifically, the second packing layer 4 includes several second membrane modules arranged horizontally, each second membrane module is wavy and placed vertically, that is, the second membrane module includes several inclined third diaphragms and fourth diaphragms, the third diaphragms and fourth diaphragms are alternately arranged, and the angles between all the upper and lower adjacent third diaphragms and fourth diaphragms are in the range of 60-180°, which can be the same or different, and can be changed in real time.

Optionally, the area of the second packing layer 4 is provided with a second support frame, the second support frame includes several sets of vertically arranged second brackets parallel to each other, each group of second brackets is arranged horizontally, and includes several second positioning bars parallel to each other and two second support bars at both ends of the second positioning bars, the second positioning bars and the second support bars are at the same level, the two second support bars are parallel to each other, the second positioning bars are perpendicular to the second support bars, that is, several "I" shapes are formed; the two ends of the second support bars are connected to the two side walls of the mixed reaction zone;

The upper and lower sides of the third diaphragm or the fourth diaphragm are respectively fixed on the second positioning rods of the upper and lower adjacent two sets of second brackets. The bottom edge of the third diaphragm and the top edge of the fourth diaphragm adjacent up and down of the same second membrane module can be fixed on the same second positioning rod.

The sewage treated in the catalytic reduction zone enters the mixed reaction zone and continues to contact the membrane while passing through the second packing layer 4 from bottom to top to degrade the remaining organic chlorine in the sewage. At the same time, the sewage in the mixed reaction zone needs to react with a coagulant or flocculant. The second packing layer 4 can cooperate with the aeration device 3 to disturb the sewage water flow and promote the reaction. Since more flocs or sludge will be produced in the mixing reaction zone, when the second membrane module inside the second packing layer 4 is wave-shaped, sludge is more likely to accumulate in the gaps, so the second support frame has a larger moving range, so that the second membrane module can become linear, which can eliminate the peaks and troughs of sludge accumulation, and is conducive to the sewage bringing most of the sludge into the sedimentation area, thus realizing the cleaning of the second packing layer 4.

Optionally, the sloping plate area 6 is provided with a number of slanting plates parallel to and inclined to each other. After the sewage undergoes coagulation or flocculation reaction, it carries most of the sludge into the sedimentation area, and first enters the slanting plate area 6 for mud-water separation.

Optionally, the bottom of the settling area can be inverted conical, and a mud scraper is provided to facilitate sludge discharge. As the scraper, the conventional scraper in this field can be used.

The loaded PVDF membrane described in this embodiment is loaded with nano-palladium and nano-iron particles, and the preparation method is as follows:

(1) configure 20wt% KOH solution, then dissolve KMnO ₄ to obtain KMnO ₄ as 10wt% KMnO ₄ -KOH solution; configure 45wt% H ₂ SO ₄ solution, then dissolve NaHSO ₃ to obtain NaHSO ₃ as 20 wt% NaHSO ₃ -H ₂ SO ₄ solution; configure 20 wt% KOH solution, and then dissolve KBH ₄ to obtain KBH ₄ as 15wt% KBH ₄ -KOH solution; configure 75wt% ethanol solution, and then dissolve Pd ₍ O ₂ CCH ₃ ) ₂ to obtain Pd(O ₂ CCH ₃ ) 2 -ethanol solution with 10wt% Pd(O ₂ CCH ₃ ) ₂ ;

(2) Wash the PVDF membrane with deionized water, soak it in KMnO ₄ -KOH solution, carry out the alkali elution chlorine reaction, react at 20°C for 2 hours, and obtain the intermediate membrane I;

(3) Wash the intermediate membrane I with deionized water, soak it in NaHSO ₃ -H ₂ SO ₄ solution, carry out hydrophilic modification, and react at 25°C for 5 hours to obtain a modified PVDF membrane;

(4) Immerse the modified PVDF membrane in 10wt% _FeSO4 solution for 15min, then vacuum-dry at 115°C for 3h to obtain a PVDF membrane loaded with Fe2 ^{+; immerse the PVDF membrane loaded with Fe2+ in} _KBH4 -KOH solution, and carry out redox reaction for 15min to obtain a PVDF membrane loaded with zero-valent iron; after cleaning the PVDF membrane loaded with zero-valent iron with absolute ethanol, quickly put it into absolute ethanol for preservation;

(5) Immerse the PVDF membrane loaded with zero-valent iron in Pd(O ₂ CCH ₃ ) ₂ -ethanol solution for 10 min, and carry out chemical deposition to obtain the loaded PVDF membrane.

Wherein, the preparation method of the PVDF membrane in step (2) is as follows:

Add 0.05g of PVDF powder into 5ml of N,N-dimethylacetamide (DMAc) solvent, stir and dissolve at 60°C, add 0.25g of pore-forming agent polyvinylpyrrolidone (PVP), and continue stirring until there is no sediment; keep the obtained casting solution sealed, and keep it at room temperature in the dark for 20 hours to remove all bubbles in the casting solution;

Under the conditions of room temperature and humidity of 60%, pour the defoamed casting solution onto a smooth glass plate, and then use a scraper to scrape out a liquid film with a uniform thickness;

Immerse the glass plate carrying the liquid film into a 20vol.% ethanol solution. At this time, the DMAc as the solvent phase slowly transfers to the solvent phase to form a porous PVDF film; after the liquid film on the glass plate becomes a solid PVDF film and completely separates from the glass plate, take out the glass plate and leave the newly formed PVDF original film in the fixative solution to continue soaking for 24 hours, so that the solvent phase can be completely released into the non-solvent phase; take out the prepared PVDF original film, clean it with distilled water, and put it in distilled water for later use.

Claims (7)

1. The catalytic reduction dechlorination device containing the supported PVDF membrane is characterized by comprising a catalytic reduction zone, a mixed reaction zone and a precipitation zone which are connected in sequence, wherein the top of the catalytic reduction zone is provided with a water inlet and a water distributor which are connected with each other, and a first filler layer is arranged below the water distributor and used for treating sewage;

the bottom of the mixing reaction zone is provided with an aeration device, the middle part of the mixing reaction zone is provided with a second filler layer, and the top of the mixing reaction zone is connected with a dosing device and is used for carrying out coagulation reaction; the first packing layer and the second packing layer are uniformly distributed with a load type PVDF film;

the sedimentation zone comprises a water producing port, an inclined plate zone and a mud discharging port from top to bottom, and the sewage is subjected to mud-water separation in the sedimentation zone to obtain produced water;

the first filler layer comprises a plurality of first membrane assemblies which are horizontally arranged, and each first membrane assembly is wavy and vertically arranged;

the first membrane component comprises a plurality of inclined first membranes and second membranes, the first membranes and the second membranes are alternately arranged, and angles between all the upper and lower adjacent first membranes and second membranes are within the range of 60-150 degrees and can be changed in real time;

the second filler layer comprises a plurality of second membrane assemblies which are horizontally arranged, each second membrane assembly is wavy and vertically arranged, each second membrane assembly comprises a plurality of inclined third membranes and fourth membranes, the third membranes and the fourth membranes are alternately arranged, and angles between all the upper and lower adjacent third membranes and fourth membranes are within the range of 60-180 degrees and can be changed in real time.

2. The catalytic reduction dechlorination device according to claim 1, characterised in that the area of the first packing layer is provided with a first support frame comprising several groups of first supports arranged vertically and parallel to each other;

each group of first supports are horizontally arranged and comprise a plurality of first positioning rods which are parallel to each other and two first support rods at two ends of each first positioning rod, the first positioning rods and the first support rods are all at the same horizontal height, the two first support rods are parallel to each other, and the first positioning rods are perpendicular to the first support rods to form a plurality of I-shaped structures; two ends of the first supporting rod are connected with two side walls of the catalytic reduction zone;

the upper side edge and the lower side edge of the first diaphragm or the second diaphragm are respectively fixed on the first positioning rods of the two groups of first brackets which are adjacent up and down, and the first positioning rods above and below the connection of the same first diaphragm or the second diaphragm are not on the same vertical line so as to ensure that the first diaphragm or the second diaphragm is obliquely arranged.

3. The catalytic reduction dechlorination device according to claim 2, characterised in that the first support frame is movable in the singular or in the plural;

the two side wall surfaces of the catalytic reduction area are respectively provided with a sliding rail corresponding to the first supporting rods, one side wall surface is provided with two vertical sliding rails which are parallel to each other, two ends of all the first supporting rods are clamped in the corresponding sliding rails, two ends of the first supporting rods of the first single-number support are respectively provided with a sliding block and can move up and down in the sliding rails, the first supporting rods of the first multiple supports are fixed in the sliding rails, the limiting effect on the upper and lower first supporting rods is achieved, and overlapping winding of upper and lower diaphragms is prevented;

the first support rod of the first singular support is of a sleeve structure and comprises an inner tube and an outer tube, two ends of the first positioning rod are fixedly connected to the corresponding outer tube, and two ends of the inner tube are clamped in the sliding rail.

4. The catalytic reduction dechlorination device according to claim 1, wherein the catalytic reduction zone is further provided with a circulation port, the circulation port is arranged below the packing layer and is connected with a water inlet of the catalytic reduction zone through a circulation pump, and the circulation port is used for partially refluxing sewage treated by the supported PVDF membrane and adjusting the state of water inflow of the catalytic reduction zone;

the water outlet of the catalytic reduction zone is arranged at the bottom of the catalytic reduction zone and is communicated with the catalytic reduction zone and the mixed reaction zone, and the sewage treated by the catalytic reduction zone is input into the mixed reaction zone.

5. The catalytic reduction dechlorination device according to claim 1, wherein the mixing reaction zone is connected with an external dosing device through a dosing pipe, the dosing device comprises a dosing pipe and a dosing pump, the dosing pipe is connected with the dosing pipe through the dosing pump, and is used for inputting coagulant or flocculant into the mixing reaction zone, and fully reacts under the stirring action of the aeration device;

the water outlet of the mixed reaction zone is arranged at the top of the mixed reaction zone and is communicated with the mixed reaction zone and the sedimentation zone, and the sewage treated by the mixed reaction zone is input into the sedimentation zone.

6. The catalytic reduction dechlorination device according to claim 1, characterised in that the region of the second packing layer is provided with a second support frame comprising several groups of second supports arranged vertically and parallel to each other,

each group of second brackets are horizontally arranged and comprise a plurality of second positioning rods which are parallel to each other and two second supporting rods at two ends of each second positioning rod, the second positioning rods and the second supporting rods are all at the same horizontal height, the two second supporting rods are parallel to each other, and the second positioning rods are perpendicular to the second supporting rods to form a plurality of I-shaped structures; two ends of the second supporting rod are connected with two side walls of the mixed reaction zone;

the upper side edge and the lower side edge of the third diaphragm or the fourth diaphragm are respectively fixed on the second positioning rods of the two groups of the second brackets which are adjacent up and down.

7. The catalytic reduction dechlorination device according to claim 1, wherein the supported PVDF membrane is loaded with nano palladium and nano iron particles, and the preparation method is as follows:

(1) Preparing KOH solution, and redissolving KMnO ₄ Obtaining KMnO ₄ -KOH solution; configuration H ₂ SO ₄ Solution, re-dissolving NaHSO ₃ Obtaining NaHSO ₃ -H ₂ SO ₄ A solution; preparing KOH solution, and redissolving KBH ₄ Obtaining KBH ₄ -KOH solution; preparing ethanol solution, and redissolving Pd (O) ₂ CCH ₃ ) ₂ Pd (O) is obtained ₂ CCH ₃ ) ₂ -an ethanol solution;

(2) Cleaning PVDF film with deionized water, soaking in KMnO ₄ In KOH solution, alkali washing and dechlorination reaction are carried out to obtain an intermediate film I;

(3) Washing the intermediate film I with deionized water, soaking in NaHSO ₃ -H ₂ SO ₄ Hydrophilic modification is carried out in the solution to obtain a modified PVDF membrane;

(4) Immersing the modified PVDF film into FeSO ₄ In the solution, then vacuum drying is carried out to obtain the loaded Fe ²⁺ A PVDF membrane of (C); will be loaded with Fe ²⁺ Is immersed in KBH in PVDF film ₄ Performing oxidation-reduction reaction in KOH solution to obtain a PVDF film loaded with zero-valent iron;

(5) Immersing zero-valent iron-loaded PVDF film in Pd (O ₂ CCH ₃ ) ₂ And (3) in ethanol solution, carrying out chemical deposition to obtain the supported PVDF film.