A radial flow three-dimensional electrode electrolytic reactor for groundwater treatment and a construction method thereof

Abstract

The application discloses a radial flow type three-dimensional electrode electrolytic reactor for groundwater treatment and a construction method. The reactor comprises a reaction bin, a sewage pipe located at the center inside the reaction bin, a plurality of radial flow electrode plates arranged in a radial outward mode and in an equidistant manner around the outside of the sewage pipe, a plurality of water outlet holes provided at positions corresponding to the radial flow electrode plates on the outer wall of the lower part of the sewage pipe, and activated carbon carrier electrode particles loaded with Cu-Ce filled in the inside of the reaction bin. The method comprises the following steps: S1, sewage injection, S2, particle electrode injection, and S3, circulation treatment. The three-dimensional electrode is constructed, so that a micro electric field is formed between the cathode and the anode, the mass transfer distance of free radicals and organic matters is greatly shortened, the attachment sites are provided for the catalytic active components, the active components participate in the dissociation of the free radicals and the oxidation-reduction reaction of the organic matters, and the reaction rate of the electrocatalytic reaction and the treatment efficiency of the electrocatalytic process are greatly improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of groundwater treatment, in particular to a radial flow type three-dimensional electrode electrolytic reactor for groundwater treatment and a construction method. BACKGROUND

[0002] In recent years, with the continuous optimization of the industrial structure of the country, many chemical enterprises are closed down and reformed, and the pollution problems of the soil and groundwater at the original site of the plant are increasingly prominent. In addition, underground oil tanks leak and organic substances are widely used, and various types of organic household goods and chemical products produce toxic and difficult-to-decompose pollutants in production, which aggravates the phenomenon of organic pollutants entering the soil and groundwater, and gradually deteriorates the soil and groundwater environment. Among them, some organic pollutants such as VOCs have strong volatility and are not easy to dissolve in water, mainly exist in the form of non-aqueous phase liquid (NAPL) in groundwater or soil and other media, and form a non-miscible multi-phase flow system with other phases, which occurs between NAPL phase, liquid phase, solid phase and gas phase through dissolution, adsorption, volatilization and other ways in the underground medium environment, so that it is difficult to be treated.

[0003] At present, the commonly used method for treating the extracted groundwater is the advanced oxidation process, which includes photochemical oxidation method, Fenton method, ozone catalytic oxidation method and electrocatalytic oxidation method. The principle of electrocatalytic reduction is similar to that of electrocatalytic oxidation, which is divided into direct reaction and indirect reaction, that is, the pollutants are transferred to the electrode surface for electrochemical reaction, or the active groups generated by the electrode enter the water body and react with the pollutants. Due to the diversity of chlorinated organic compounds, there are relatively complex by-products in the dechlorination process, such as organic intermediates and chlorine-containing oxygen acids, and some by-products cannot be completely removed by the process of treating target pollutants, so the dechlorination by-products and degradation pathways are also one of the hotspots in the research of electrocatalysis.

[0004] The three-dimensional electrode structure was proposed in the 1960s. The particle or crumb-shaped particle electrode is added between the traditional anode and the traditional cathode. Due to electrostatic induction, positive and negative charges are respectively generated at both ends of the particle, a plurality of micro-electrodes can be constructed, the mass transfer distance of free radicals and organic matter is shortened, a three-dimensional reaction system is formed, and the attachment sites for the catalytically active components are provided.

[0005] At present, there are many researches on the equipment of electro-catalytic oxidation method, some people improve the structure of electrolytic cell or electrode plate, or increase some auxiliary means to improve the electrolysis efficiency, for example, the patent with the publication number CN104372375A discloses a water electrolytic cell device capable of accelerating oxygen / hydrogen separation from electrode plate, which comprises a water electrolytic cell body, the water electrolytic cell body has a containing space for containing electrolyte and is internally provided with electrodes and electrode plates, the water electrolytic cell device is further provided with a power control part and an ultrasonic vibration mechanism connected therewith. The invention increases the power control part and the ultrasonic vibration mechanism on the water electrolytic cell, the power control part can monitor the current and voltage loaded on the electrode plate in real time, and supply the most suitable voltage and current to the electrode plate according to the feedback result, so that the electrolysis reaction reaches the best state, and the generation amount of bubbles on the surface of the electrode plate is increased; at the same time, the ultrasonic vibration mechanism transmits vibration to the electrode plate in the form of ultrasonic wave, so that the electrode plate vibrates, the bubbles adhered thereto are forced to vibrate and quickly separate to float up, the generation of oxygen and hydrogen mixed gas is accelerated, and the utilization of the mixed gas is more convenient. However, the method of single ultrasonic application has limited effect on the improvement of electro-catalytic oxidation efficiency, and at present, it only stays in two-dimensional electrode, but the three-dimensional electrode needs to be further researched. SUMMARY

[0006] In view of the above problems, the present application provides a radial flow type three-dimensional electrode electrolytic reactor for groundwater treatment and a construction method.

[0007] The technical scheme of the present application is as follows:

[0008] A radial flow type three-dimensional electrode electrolytic reactor for groundwater treatment, comprising a reaction bin, a sewage pipe located at the center inside the reaction bin, a plurality of radial flow electrode plates arranged in a radial manner and equidistantly around the outside of the sewage pipe, and a plurality of water outlet holes provided on the outer wall of the lower part of the sewage pipe corresponding to the positions of the radial flow electrode plates.

[0009] A plurality of grooves are provided on the inner side of the radial flow electrode plate, and a group of stirring plates is provided corresponding to each groove, the stirring plates are equidistantly arranged, the stirring plates on the same stirring plate group are fixedly connected through a rotating ring, the rotating ring is rotatably connected to the outside of the sewage pipe, and the rotating rings are synchronously rotated through a driving motor.

[0010] A top cover is provided on the top of the reaction bin, an opening is provided in the middle of the top cover, the sewage pipe penetrates through the opening, a first water outlet pipe is provided on the side wall of the reaction bin near the lower part of the top cover, a water pump is connected to the end of the first water outlet pipe, a reflux pipe is provided at the water outlet end of the water pump, and the reflux pipe is communicated with the top of the sewage pipe.

[0011] The reaction bin is filled with particle electrodes, and a feeding pipe is provided on one side of the upper part of the reaction bin.

[0012] Further, each of the rotating rings is fixedly connected through two symmetrically arranged first connecting rods, the first connecting rods extend to the upper outer side of the reaction bin, each first connecting rod is provided with a second connecting rod at the end, the ends of each of the second connecting rods are commonly connected with a rotating disc, the center of the rotating disc coincides with the center of the sewage pipe, a limiting block is arranged on the inner side wall of the rotating ring, and the limiting block is in sliding connection with the limiting groove arranged on the outer wall of the sewage pipe.

[0013] Description: The first connecting rod and the second connecting rod are used to control the rotating ring, so that the rotating ring can rotate under the driving of the rotating disc, and the stability of the rotating ring during rotation is maintained by the limiting block and the limiting groove.

[0014] Further, a gear slot is arranged on the outer wall of the rotating disc, a driving gear is engagedly connected to one side of the outer wall of the rotating disc through the gear slot, the driving gear is driven to rotate by the driving motor, and the rear side of the driving motor is fixedly connected with the outer wall of the building through a fixing rod.

[0015] Description: The gear slot and the driving gear are used to drive the rotating disc to rotate.

[0016] Further, a plurality of support blocks with the same height are arranged at equal intervals at the bottom of the rotating disc, the support blocks are in sliding connection with the sliding grooves arranged on the bottom of the rotating disc, and the support blocks are fixedly arranged on the upper surface of the top cover.

[0017] Description: The support blocks are used to maintain the stability of the rotating disc during rotation.

[0018] Further, the radial flow electrode plates are 6-8, and the stirring plate groups are 3, and the stirring plates on each stirring plate group are 4-6.

[0019] Description: The number of radial flow electrode plates is optimized and adjusted, so that the treatment effect on the contaminated groundwater is further improved; generally, the more the electrode plates are arranged, the greater the current is and the better the treatment effect is, but in the present application, too many radial flow electrode plates will cause temperature rise, reduced rotating efficiency and increased failure rate, so the number of the radial flow electrode plates needs to be reasonably arranged; the stirring plate groups are arranged in the same way, too many stirring plate groups will occupy more space, so as to compress the movement space of the activated carbon carrier electrode particles, and too few stirring plate groups cannot well play the stirring role.

[0020] Further, the diameters of the water outlets distributed between two adjacent rotating rings are the same, and according to the position distribution of the water outlets, a first water outlet area is formed between the uppermost rotating ring and the rotating ring in the middle, a second water outlet area is formed between the rotating ring in the middle and the lower rotating ring, and a third water outlet area is formed below the lower rotating ring, the diameters of the water outlets gradually decrease from the first water outlet area to the third water outlet area, the diameter distribution of the water outlets in the first water outlet area is 20-30 mm, the diameter distribution of the water outlets in the second water outlet area is 10-20 mm, and the diameter distribution of the water outlets in the third water outlet area is 5-10 mm.

[0021] Description: By dividing multiple water outlet areas and optimizing the diameter distribution of the water outlets, the water outlet is more uniform, and because the water flows naturally downward, the lower water outlets are in contact with the electrode plate for a longer time, so the water outlets are designed to have diameters gradually decreasing from top to bottom, more water is distributed in the upper half of the radial flow electrode plate, thereby increasing the contact time of the water flow and the pollutants with the electrode plate and improving the treatment efficiency.

[0022] Further, the bottom side wall of the reaction chamber is provided with a second water outlet pipe and an air guide pipe, one side of the top cover is provided with a foam discharge port, the power lines provided on the side edges of the radial flow electrode plate all penetrate the top cover and are connected with an external power source, the bottom of the radial flow electrode plate is provided with a fixing block, a fixing groove is arranged in the fixing block, the fixing block is clamped to the bottom of the radial flow electrode plate, and the rear side wall of the fixing block is fixedly connected with the inner wall of the reaction chamber.

[0023] Description: The stability of the radial flow electrode plate during work is maintained by the fixing block.

[0024] Further, the particle electrode is a Cu-Ce-loaded activated carbon carrier electrode particle, and the preparation method of the Cu-Ce-loaded activated carbon carrier electrode particle is as follows:

[0025] S1, pretreatment: the activated carbon powder is washed with deionized water for three times, completely immersed in a hydrochloric acid solution with a molar concentration of 1 mol / L, ultrasonic treated for 30-40 min, then continuously soaked for 1-2 h, taken out, washed with deionized water until the pH is neutral, and placed in an oven at 100-105℃ for drying for 1-2 h, and the pretreated activated carbon powder is taken out and reserved;

[0026] S2, Cu-Ce loading: the molar concentration of 40-50 mmol / L of Cu(NO3)2 solution and Ce(NO3)2 solution is mixed in a weight ratio of 1:1 to obtain an impregnated salt solution, the pretreated activated carbon powder is immersed in the impregnated salt solution for 20-24 h, then placed in a 100-105℃ oven for drying for 1-2 h, and then placed in a muffle furnace for calcination at 500-550℃ for 2-3 h, and then washed with deionized water for three times, placed in a 100-105℃ oven for drying for 1-2 h, and then cooled to obtain the Cu-Ce loaded activated carbon carrier electrode particles.

[0027] Description: through the preferred Cu-Ce loaded activated carbon carrier electrode particles, the Cu and Ce bimetallics have a bimetallic synergistic effect, and have excellent catalytic activity, and the effect of electrocatalytic oxidation treatment of organic wastewater is significantly enhanced.

[0028] Further, in S1, the particle size of the activated carbon powder is less than 50 μm, the ultrasonic power is 80-100 Hz, and the weight ratio of the activated carbon powder to hydrochloric acid is 1:1-2.

[0029] Description: the ultrasonic treatment promotes the acid pickling effect of the activated carbon powder.

[0030] On the other hand, the application also provides a construction method of a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment, comprising the following steps:

[0031] S1, sewage injection: the sewage to be treated is injected into the sewage pipe, enters the reaction chamber through the water outlet hole (21) on the sewage pipe, and then the radial flow electrode plate is powered to form a radial flow mode from the center to the outside when the sewage flows out, and the current density is adjusted to 70-100 A / m 2 ;

[0032] S2, particle electrode injection: the particle electrode is added to the inside of the reaction chamber through the feeding pipe, and the addition amount is 200-240 g / L of sewage;

[0033] S3, circulating treatment: the water pump is started to pump out the sewage rising to the first water outlet pipe, and then re-injected into the inside of the sewage pipe through the backflow pipe to form a continuous circulating treatment, and the hydraulic retention time is 40-100 min, and the water pump flow rate is 1-3 L / h.

[0034] The beneficial effects of the application are:

[0035] (1) The application constructs a three-dimensional electrode by adding Cu-Ce loaded activated carbon carrier electrode particles into the radial flow electrolytic cell, thereby forming a micro-electric field between the anode and the cathode, greatly shortening the mass transfer distance of free radicals and organic matter, and providing an attachment site for the catalytically active component, so that the active component participates in the dissociation of free radicals and the oxidation-reduction reaction of organic matter, greatly improving the reaction rate of electrocatalytic reaction and the treatment efficiency of electrocatalytic process, thereby solving the problem of large electrode spacing at a distance from the water inlet pipe in the radial flow electrolytic cell reactor, and providing a solution for reducing the cost of electrocatalytic electrode materials.

[0036] (2) The radial flow electrode plates are arranged in a radial manner in the reaction chamber, which can effectively utilize the electrode area and improve the treatment effect, and the rotating stirring plate group improves the sewage flow rate during continuous rotation, promotes the contact efficiency between the Cu-Ce loaded activated carbon carrier electrode particles and the sewage, enhances the convective mass transfer of pollutants to the radial flow electrode plates, and strengthens the treatment effect.

[0037] (3) The application also improves and innovates the particle electrode of the prior art, and prepares Cu-Ce loaded activated carbon carrier electrode particles to replace the particle electrode of the prior art, wherein the Cu and Ce bimetallic metals have a bimetallic synergistic effect, have excellent catalytic activity, have a significant enhancing effect on the electrocatalytic oxidation treatment of organic wastewater, and have good application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a whole structure schematic diagram of a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment of the application;

[0039] Figure 2 is a front view of a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment of the application;

[0040] Figure 3 is a schematic diagram of the internal structure of a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment of the application;

[0041] Figure 4 is a top view of a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment of the application;

[0042] Figure 5 is a schematic diagram of the structure of the water outlet hole on the sewage pipe of a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment of the application;

[0043] Figure 6 is a schematic diagram of the connection structure of the radial flow electrode plate and the fixing block of a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment of the application;

[0044] Figure 7It is a limiting block and limiting groove connecting structure diagram of a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment of the present application;

[0045] Figure 8 It is a rotating disc and driving gear connecting structure diagram of a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment of the present application.

[0046] Wherein, 1-reaction bin, 11-first water outlet pipe, 12-feeding pipe, 13-second water outlet pipe, 14-air guide pipe, 2-sewage pipe, 21-water outlet hole, 22-limiting groove, 3-radial flow electrode plate, 31-slotted, 32-power line, 33-fixing block, 34-fixing groove, 4-stirring plate group, 41-stirring plate, 42-rotating ring, 43-first connecting rod, 44-second connecting rod, 45-limiting block, 5-driving motor, 51-driving gear, 52-fixing rod, 6-top cover, 61-opening, 62-foam discharge port, 7-water pump, 71-backflow pipe, 8-rotating disc, 81-gear slot, 82-supporting block, 83-sliding groove. DETAILED DESCRIPTION

[0047] Example 1

[0048] As shown in Figure 1 and Figure 3 , a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment, comprising a reaction bin 1, a sewage pipe 2 located at the center inside the reaction bin 1, 8 radial flow electrode plates 3 arranged outwardly and equidistantly around the outside of the sewage pipe 2, and a plurality of water outlet holes 21 provided on the outer wall of the lower part of the sewage pipe 2 corresponding to the positions of the radial flow electrode plates 3.

[0049] As shown in Figures 2-4 , Figure 7 , the inner side of the radial flow electrode plate 3 is provided with 3 slotted 31, and a set of stirring plate group 4 is provided at each slotted 31. The stirring plate group 4 comprises 4 stirring plates 41 arranged equidistantly in a circle, and each stirring plate 41 in the same stirring plate group 4 is fixedly connected by a rotating ring 42. The rotating ring 42 is rotatably sleeved on the outside of the sewage pipe 2. The rotating rings 42 are fixedly connected by two symmetrically arranged first connecting rods 43. The first connecting rods 43 extend to the outside of the upper part of the reaction bin 1. The ends of each first connecting rod 43 are provided with a second connecting rod 44. The ends of each second connecting rod 44 are jointly connected to a rotating disc 8. The center of the rotating disc 8 coincides with the center of the sewage pipe 2. The inner wall of the rotating ring 42 is provided with a limiting block 45. The limiting block 45 is slidably connected with the limiting groove 22 provided on the outer wall of the sewage pipe 2.

[0050] As shown in Figure 3 and Figure 8As shown, each rotating ring 42 is driven to rotate synchronously by the driving motor 5, the outer wall of the rotating disc 8 is provided with a gear slot 81, and the driving gear 51 is connected to the outer wall of the rotating disc 8 through the gear slot 81 on one side, the driving gear 51 is driven to rotate by the driving motor 5, the driving motor 5 is a commercially available gear reduction motor, the rear side of the driving motor 5 is fixedly connected to the outer wall through the fixed rod 52, and the bottom of the rotating disc 8 is provided with a plurality of support blocks 82 with the same height at equal intervals, the top of the support block 82 is slidably connected to the sliding groove 83 provided on the bottom of the rotating disc 8, and the support block 82 is fixedly arranged on the upper surface of the top cover 6.

[0051] As shown in Figure 3 and Figure 5 shown, the water outlet holes 21 distributed between the adjacent two rotating rings 42 have the same diameter, according to the position distribution of the water outlet holes 21, the first water outlet area is formed between the uppermost rotating ring 42 and the rotating ring 42 in the middle, the second water outlet area is formed between the rotating ring 42 in the middle and the rotating ring 42 below, and the third water outlet area is formed below the rotating ring 42 below, the diameter of the water outlet holes 21 gradually decreases from the first water outlet area to the third water outlet area, the diameter of the water outlet holes 21 in the first water outlet area is 25mm, the diameter of the water outlet holes 21 in the second water outlet area is 15mm, and the diameter of the water outlet holes 21 in the third water outlet area is 8mm.

[0052] The top of the reaction bin 1 is provided with a top cover 6, the middle of the top cover 6 is provided with an opening 61, the sewage pipe 2 penetrates through the opening 61, the side wall of the reaction bin 1 near the bottom of the top cover 6 is provided with a first water outlet pipe 11, the end of the first water outlet pipe 11 is connected with a water pump 7, and the water outlet end of the water pump 7 is provided with a backflow pipe 71 in communication with the top of the sewage pipe 2.

[0053] As shown in Figure 3 and Figure 6 shown, the power lines 32 provided on the side edges of the radial flow electrode plate 3 all penetrate through the rear of the top cover 6 and are connected with the external power supply, the bottom of the radial flow electrode plate 3 is provided with a fixing block 33, the fixing groove 34 provided in the fixing block 33 is clamped with the bottom of the radial flow electrode plate 3, and the rear wall of the fixing block 33 is fixedly connected with the inner wall of the reaction bin 1.

[0054] As shown in Figure 1 and Figure 2 shown, the reaction bin 1 is filled with a particle electrode, the particle electrode is activated carbon powder, the particle size of the activated carbon powder is less than 50μm, one side of the upper part of the reaction bin 1 is provided with a feeding pipe 12, the side wall of the bottom of the reaction bin 1 is provided with a second water outlet pipe 13 and an air guide pipe 14, and one side of the top cover 6 is provided with a foam discharge port 62.

[0055] Example 2

[0056] The difference between this embodiment and example 1 is that:

[0057] The sewage pipe 2 is externally circumferentially provided with 6 outward radiation type radial flow electrode plates 3, and the stirring plate group 4 comprises 4 circumferentially equidistantly arranged stirring plates 41.

[0058] Example 3

[0059] The difference between this embodiment and example 1 is that:

[0060] The first water outlet area has water outlet holes 21 with a diameter distribution of 20mm, the second water outlet area has water outlet holes 21 with a diameter distribution of 10mm, and the third water outlet area has water outlet holes 21 with a diameter distribution of 5mm.

[0061] Example 4

[0062] The difference between this embodiment and example 1 is that:

[0063] The first water outlet area has water outlet holes 21 with a diameter distribution of 30mm, the second water outlet area has water outlet holes 21 with a diameter distribution of 20mm, and the third water outlet area has water outlet holes 21 with a diameter distribution of 10mm.

[0064] Note: When the volume of the contaminated groundwater to be treated is larger, the diameter of the water outlet hole 21 is larger, and the diameter distribution of the three water outlet areas should be proportional. According to the volume of the contaminated groundwater to be treated, the parameters in example 1 or examples 3-4 are reasonably selected.

[0065] Example 5

[0066] The difference between this embodiment and example 1 is that the particle electrode is a Cu-Ce loaded activated carbon carrier electrode particle, and the preparation method of the Cu-Ce loaded activated carbon carrier electrode particle is:

[0067] S1, pretreatment: take activated carbon powder and wash it three times with deionized water, the particle size of the activated carbon powder is less than 50μm, completely immerse it in a hydrochloric acid solution with a molar concentration of 1mol / L, the weight ratio of the activated carbon powder to the hydrochloric acid is 1:1, after ultrasonic treatment for 30min, continue to soak for 1h, then take it out, the ultrasonic power is 80Hz, wash it with deionized water until the pH is neutral, and place it in a 100℃ oven to dry for 1h, then take out the pretreated activated carbon powder for standby;

[0068] S2, Cu-Ce loading: mix Cu(NO3)2 solution and Ce(NO3)2 solution with a molar concentration of 40mmol / L at a weight ratio of 1:1 to obtain an impregnated salt solution, immerse the pretreated activated carbon powder in the impregnated salt solution for 20h, then place it in a 100℃ oven to dry for 1h, and then place it in a muffle furnace to calcine at 500℃ for 2h, then take it out and wash it with deionized water three times, place it in a 100℃ oven to dry for 1h, and then cool it to obtain the Cu-Ce loaded activated carbon carrier electrode particle.

[0069] Example 6

[0070] The difference between this embodiment and Example 5 is that the particle electrode is a Cu-Ce loaded activated carbon carrier electrode particle, and the preparation method of the Cu-Ce loaded activated carbon carrier electrode particle is as follows:

[0071] S1, pretreatment: take the activated carbon powder and wash it with deionized water three times, the particle size of the activated carbon powder is less than 50 μm, completely immerse the activated carbon powder in a hydrochloric acid solution with a molar concentration of 1 mol / L, the weight ratio of the activated carbon powder to the hydrochloric acid is 1:2, after ultrasonic treatment for 40 min, continue to soak for 2 h, then take it out, the ultrasonic power is 100 Hz, wash it with deionized water until the pH is neutral, and place it in a 105°C oven to dry for 2 h, then take out the pretreated activated carbon powder for standby;

[0072] S2, Cu-Ce loading: mix Cu(NO3)2 solution and Ce(NO3)2 solution with a molar concentration of 50 mmol / L at a weight ratio of 1:1 to obtain an impregnated salt solution, immerse the pretreated activated carbon powder in the impregnated salt solution for 24 h, then place it in a 105°C oven to dry for 2 h, then place it in a muffle furnace to calcine at 550°C for 3 h, then take it out and wash it with deionized water three times, then place it in a 105°C oven to dry for 2 h, and then cool it to obtain the Cu-Ce loaded activated carbon carrier electrode particle.

[0073] Note: In Examples 5 and 6, the selected parameters are all within the reasonable range of conventional adjustment, and any one set of parameters in Examples 5 and 6 can achieve similar technical effects, and further research on the effects of impregnated salt solution concentration and calcination temperature will be carried out.

[0074] Example 7

[0075] This embodiment describes a method for constructing a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment according to Example 5, which comprises the following steps:

[0076] S1, sewage injection: inject the sewage to be treated into the sewage pipe 2, and then into the reaction chamber 1 through the water outlet hole 21 on the sewage pipe 2, and then power the radial flow electrode plate 3, so that the sewage forms a radial flow pattern from the center to the outside when flowing out, and the current density is adjusted to 80 A / m 2 ;

[0077] S2, particle electrode injection: add particle electrodes to the inside of the reaction chamber 1 through the feeding pipe 12, and the addition amount is 220 g / L of sewage;

[0078] S3, circulating treatment: open the water pump 7 to pump out the sewage rising to the first water outlet pipe 11, and re-inject into the sewage pipe 2 through the backflow pipe 71, forming continuous circulating treatment, the hydraulic retention time is 60 min, the flow rate of water pump 7 is 2L / h.

[0079] Example 8

[0080] The difference between this embodiment and example 7 is:

[0081] S1, sewage injection: inject the sewage to be treated into the sewage pipe 2, enter into the reaction chamber 1 through the water outlet hole 21 on the sewage pipe 2, and then power on the radial flow electrode plate 3, so that the sewage forms a radial flow pattern from the center to the outside when flowing out, and the current density is adjusted to 70A / m 2 ;

[0082] S2, particle electrode injection: add particle electrodes into the reaction chamber 1 through the feeding pipe 12, the addition amount is 200g / L sewage;

[0083] S3, circulating treatment: open the water pump 7 to pump out the sewage rising to the first water outlet pipe 11, and re-inject into the sewage pipe 2 through the backflow pipe 71, forming continuous circulating treatment, the hydraulic retention time is 40 min, the flow rate of water pump 7 is 1L / h.

[0084] Example 9

[0085] The difference between this embodiment and example 7 is:

[0086] S1, sewage injection: inject the sewage to be treated into the sewage pipe 2, enter into the reaction chamber 1 through the water outlet hole 21 on the sewage pipe 2, and then power on the radial flow electrode plate 3, so that the sewage forms a radial flow pattern from the center to the outside when flowing out, and the current density is adjusted to 100A / m 2 ;

[0087] S2, particle electrode injection: add particle electrodes into the reaction chamber 1 through the feeding pipe 12, the addition amount is 240g / L sewage;

[0088] S3, circulating treatment: open the water pump 7 to pump out the sewage rising to the first water outlet pipe 11, and re-inject into the sewage pipe 2 through the backflow pipe 71, forming continuous circulating treatment, the hydraulic retention time is 100 min, the flow rate of water pump 7 is 3L / h.

[0089] Note: in examples 8 and 9, different sewage body volumes are mainly optimized, when the sewage body volume is large, the parameters in example 9 are selected, and when the sewage body volume is small, the parameters in example 8 are selected.

[0090] Working principle:

[0091] The working principle of the radial flow three-dimensional electrode electrolytic reactor for groundwater treatment according to the present application is further described below in combination with the construction method in Example 5.

[0092] When the S3 cycle processing is performed, the stirring plate group 4 needs to be rotated to improve the contact efficiency between the Cu-Ce loaded activated carbon carrier electrode particles and the sewage, the driving motor 5 is turned on to drive the driving gear 51 to rotate, thereby driving the rotating disc 8 to rotate under the meshing action of the tooth groove 81, thereby driving each rotating ring 42 to rotate through the second connecting rod 44 and the first connecting rod 43, while the limiting block 45 rotates in the limiting groove 22 to maintain the overall stability of each rotating ring 42 and the stirring plate group 4, and at the same time, the rotation and stirring of each stirring plate 41 can be realized, and the stirring plate 41 rotates through the slot 31 to avoid affecting the radial flow electrode plate 3.

[0093] Experimental Example 1

[0094] The actual sewage treatment effect of the radial flow three-dimensional electrode electrolytic reactor for groundwater treatment according to Example 5 of the present application is tested below, and compared with that of a common electrolytic tank reactor. The common electrolytic tank reactor of Comparative Example 1 is only provided with the same radial flow electrode plate 3 as in Example 1, without adding the Cu-Ce loaded activated carbon carrier electrode particles. The detection method is as follows: the qualitative semi-quantitative analysis of the test sample is performed by a 7890B type gas chromatograph-2YF-DC-019 type mass spectrometer, the detected compounds are automatically identified by Masshunter software, and the matching degree is higher than 80%; according to the Water and Wastewater Test Analysis Method (Fourth Edition), the metal ion content in the solution is determined by an iCAP7400DuoMFC type inductively coupled plasma emission spectrometer. The results are shown in Table 1.

[0095] Table 1 Comparison of treatment results of the present application and comparative examples

[0096]

[0097] It can be seen that the COD removal rate of the reactor of the present application for contaminated groundwater has been significantly improved, while the electrode plate area applied for treating per unit volume of wastewater is greatly reduced, and the electric power consumption for treating the same volume of contaminated groundwater is slightly higher than that of the common electrolytic tank reactor.

[0098] Experimental Example 2

[0099] The actual sewage treatment effect of the radial flow three-dimensional electrode electrolytic reactor for groundwater treatment according to Example 5 of the present application is tested below, and the influence of the concentration of the mixed salt solution is further studied. In Comparative Example 2, the molar concentration of the mixed salt solution is 0.5 mmol / L, and in Comparative Example 3, the molar concentration of the mixed salt solution is 15 mmol / L, and the results are shown in Table 2.

[0100] Table 2 Comparison of treatment results of the present application and comparative examples

[0101] Case COD removal % The present invention 92.39 Comparative Example 2 85.25 Comparative Example 3 86.37

[0102] It can be observed that in the range of 0-50 mmol / L, with the increase of the impregnation concentration of the particle electrode, the catalytic ability of the particle electrode is enhanced and the COD removal rate is increased due to the increase of the content of Cu 2+ and Ce 3+ active components. When the impregnation concentration reaches 50 mmol / L, the Cu 2+ leaching concentration reaches a certain level, and further increasing the impregnation concentration will cause more serious Cu 2+ leaching. Excessive leaching concentration will not only cause the loss of active components and lead to unstable catalytic effect, but also cause secondary pollution to the target water body. Therefore, 50 mmol / L is selected as the optimal impregnation concentration.

[0103] Example 3

[0104] Next, we test the actual sewage treatment effect of a radial flow three-dimensional electrode electrolytic reactor for groundwater treatment according to Example 5 of the present application, and further study the influence of calcination temperature. In Comparative Example 4, the calcination temperature is 400°C, and in Comparative Example 5, the calcination temperature is 600°C. The results are shown in Table 3.

[0105] Table 3 Comparison of treatment results of the present application and comparative examples

[0106] Case COD removal % The present invention 92.39 Comparative Example 4 90.75 Comparative Example 5 91.21

[0107] It can be observed that when the calcination temperature is between 400°C and 500°C, with the increase of the temperature, the combination ability of Cu 2+ and Ce 3+ with the surface of activated carbon is enhanced, the catalytic degradation effect is significantly improved, and the leaching concentration is reduced. When the temperature is above 500°C, with the increase of the temperature, the COD removal effect is decreased, and the Cu 2+ leaching concentration is increased, which may be due to the structure collapse and the exfoliation of the skin active metal oxide at high temperature, resulting in the weakening of the catalytic ability of Cu 2+ and Ce 3+ active components. The comparison of experimental phenomena and the optimal temperature range is close to the description in the literature. Therefore, 500°C is selected as the optimal temperature for calcination of activated carbon.

Claims

1. A radial flow three-dimensional electrode electrolysis reactor for groundwater treatment, characterized in that, It includes a reaction chamber (1), a sewage pipe (2) located at the center of the reaction chamber (1), and a number of radial current electrode plates (3) arranged in an outwardly radiating manner around the outside of the sewage pipe (2) at equal intervals. A number of water outlet holes (21) are provided on the lower outer wall of the sewage pipe (2) corresponding to the location of the radial current electrode plates (3). The radial current electrode plate (3) has several slots (31) on its inner side. A set of stirring plate group (4) is provided at each slot (31). The stirring plate group (4) includes several stirring plates (41) arranged at equal intervals in the circumference. Each stirring plate (41) on the same stirring plate group (4) is fixedly connected by a rotating ring (42). The rotating ring (42) is rotatably sleeved on the outside of the sewage pipe (2). Each rotating ring (42) is driven to rotate synchronously by a drive motor (5). Each of the rotating rings (42) is fixedly connected by two symmetrically arranged first connecting rods (43). The first connecting rods (43) extend to the upper outer side of the reaction chamber (1). Each of the first connecting rods (43) is provided with a second connecting rod (44) at the end. Each of the second connecting rods (44) is connected to a turntable (8) at the end. The center of the turntable (8) coincides with the center of the sewage pipe (2). A limiting block (45) is provided on the inner side wall of the rotating ring (42). The limiting block (45) is slidably connected to the limiting groove (22) corresponding to the outer wall of the sewage pipe (2). The reaction chamber (1) is provided with a top cover (6) and an opening (61) in the middle of the top cover (6). The sewage pipe (2) passes through the opening (61). A first water outlet pipe (11) is provided on the side wall of the reaction chamber (1) near the bottom of the top cover (6). A water pump (7) is connected to the end of the first water outlet pipe (11). A return pipe (71) is provided at the water outlet end of the water pump (7). The return pipe (71) is connected to the top of the sewage pipe (2). The reaction chamber (1) is filled with particle electrodes, and a feeding pipe (12) is provided on one side of the upper part of the reaction chamber (1); The particle electrode is a Cu-Ce-loaded activated carbon support electrode particle, and the preparation method of the Cu-Ce-loaded activated carbon support electrode particle is as follows: S1. Pretreatment: Take activated carbon powder and wash it three times with deionized water. Then, completely immerse it in a hydrochloric acid solution with a molar concentration of 1 mol / L. After ultrasonic treatment for 30-40 minutes, continue soaking for 1-2 hours. Take it out, wash it with deionized water until the pH is neutral, and dry it in an oven at 100-105℃ for 1-2 hours. Take out the pretreated activated carbon powder for later use. S2, Cu-Ce loading: Cu(NO3)2 solution and Ce(NO3)2 solution, both with a molar concentration of 40-50 mmol / L, are mixed at a weight ratio of 1:1 to obtain an impregnation salt solution. The pretreated activated carbon powder is impregnated in the impregnation salt solution for 20-24 hours, then dried in an oven at 100-105℃ for 1-2 hours, and then calcined in a muffle furnace at 500-550℃ for 2-3 hours. After removal, it is washed three times with deionized water, dried in an oven at 100-105℃ for 1-2 hours, and cooled to obtain Cu-Ce loaded activated carbon carrier electrode particles.

2. The radial flow three-dimensional electrode electrolysis reactor for groundwater treatment according to claim 1, characterized in that, The turntable (8) has a toothed groove (81) on its outer side wall. A drive gear (51) is connected to one side of the turntable (8) through the toothed groove (81). The drive gear (51) is driven to rotate by the drive motor (5). The rear side of the drive motor (5) is fixedly connected to the outer wall through a fixing rod (52).

3. The radial flow three-dimensional electrode electrolysis reactor for groundwater treatment according to claim 1, characterized in that, The turntable (8) has several support blocks (82) of the same height at equal intervals at the bottom. The top of the support block (82) is slidably connected to the slide groove (83) provided at the bottom of the turntable (8). The support block (82) is fixedly set on the upper surface of the top cover (6).

4. The radial flow three-dimensional electrode electrolysis reactor for groundwater treatment according to claim 1, characterized in that, There are 6 to 8 radial current electrode plates (3), 3 stirring plate groups (4), and 4 to 6 stirring plates (41) on each stirring plate group (4).

5. A radial flow three-dimensional electrode electrolysis reactor for groundwater treatment according to claim 4, characterized in that, The outlet holes (21) distributed between two adjacent rotating rings (42) have the same diameter. According to the position distribution of the outlet holes (21), the first water outlet area is formed between the uppermost rotating ring (42) and the middle rotating ring (42), the second water outlet area is formed between the middle rotating ring (42) and the lower rotating ring (42), and the third water outlet area is formed below the lower rotating ring (42). The diameter of the outlet holes (21) gradually decreases from the first water outlet area to the third water outlet area. The diameter distribution of the outlet holes (21) in the first water outlet area is 20-30 mm, the diameter distribution of the outlet holes (21) in the second water outlet area is 10-20 mm, and the diameter distribution of the outlet holes (21) in the third water outlet area is 5-10 mm.

6. A radial flow three-dimensional electrode electrolysis reactor for groundwater treatment according to claim 1, characterized in that, The bottom side wall of the reaction chamber (1) is provided with a second water outlet pipe (13) and a gas guide pipe (14). The top cover (6) is provided with a foam outlet (62) on one side. The power line (32) provided on the side of the radial current electrode plate (3) passes through the top cover (6) and is connected to an external power source. The bottom of the radial current electrode plate (3) is provided with a fixing block (33). The fixing groove (34) provided inside the fixing block (33) is engaged with the bottom of the radial current electrode plate (3). The rear side wall of the fixing block (33) is fixedly connected to the inner wall of the reaction chamber (1).

7. A radial flow three-dimensional electrode electrolysis reactor for groundwater treatment according to claim 1, characterized in that, In S1, the particle size of the activated carbon powder is less than 50 μm, the ultrasonic power is 80-100 Hz, and the weight ratio of activated carbon powder to hydrochloric acid is 1:1-2.

8. A method for constructing a radial flow three-dimensional electrode electrolysis reactor for groundwater treatment according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Wastewater Injection: The wastewater to be treated is injected into the wastewater pipe (2) and enters the reaction chamber (1) through the outlet (21) on the wastewater pipe (2). Then, electricity is applied to the radial current electrode plate (3) so that the wastewater flows out in a radial flow pattern from the center outward. The current density is adjusted to 70-100 A / m. 2 ; S2, Particle Electrode Injection: Particle electrodes are added into the reaction chamber (1) through the feed pipe (12), with an addition amount of 200-240 g / L wastewater; S3. Circulation treatment: Turn on the water pump (7) to extract the sewage that rises to the first outlet pipe (11) and re-inject it into the sewage pipe (2) through the return pipe (71) to form a continuous circulation treatment. The hydraulic residence time is 40 to 100 minutes and the flow rate of the water pump (7) is 1 to 3 L / h.

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