CN111646539A - UVC-LED-DSA electrode coupled photoelectrochemistry oxidized ammonia nitrogen synergistic removal system - Google Patents

Abstract

The invention discloses a UVC-LED-DSA electrode-coupled photoelectrochemical ammonia nitrogen oxidation synergistic removal system. The system comprises: a photoelectrochemical reactor, a DSA anode, a titanium cathode, a magnetic stirrer, a peristaltic pump, an anode gas outlet, and a cathode Air outlet, pH controller, DC power supply, thermocouple, temperature control device, UVC‑LED module (air-cooled cooling fan, heat sink, UVC‑LED lamp beads), quartz glass plate. The system of the invention mainly consumes electric energy, can operate efficiently at a lower current density, has a lower operating cost, and has a simple structure, small volume, simple operation and easy maintenance of the reaction device; the DSA anode used has good electrocatalytic activity It has good stability, corrosion resistance, electrical conductivity and processability, which can greatly improve the service life of the system; in addition, the photoelectrochemical oxidation reaction system mainly removes pollutants such as ammonia nitrogen and other pollutants quickly and efficiently by generating active chlorine and various free radical components. Green, environmentally friendly and other characteristics.

Description

A UVC-LED-DSA electrode coupled photoelectrochemical oxidation of ammonia nitrogen synergistic removal system

technical field

The invention relates to the fields of UV-LED photoelectrochemical oxidation technology, aquaculture water purification and sewage cleaning treatment, in particular to a UVC-LED-DSA electrode coupling photoelectrochemical oxidation ammonia nitrogen synergistic removal system.

Background technique

Since the end of the 20th century, in order to obtain more high-quality animal protein, the world's major fishing countries have begun to attach importance to the development of aquaculture, which has made aquaculture one of the fastest growing industries in agriculture. With the shortage of water resources in my country and the intensification of prevention and control of environmental pollution and food safety, the traditional and extensive aquaculture model is further restricted, and the continuous growth of aquatic product consumption demand makes aquaculture inevitable to be more intensive, efficient, green and sustainable. Continued technological transformation of industrial recirculating aquaculture. Industrial recirculating aquaculture technology is a technology that integrates modern technologies to realize the recycling of aquaculture water, reduce environmental pollution and improve water utilization. During the breeding process, proteins such as metabolites, bait residues, and biological corpses cannot be decomposed in time. Studies have shown that more than 80% of the bait eaten by fish in the recirculating aquaculture system is used as waste (mainly ammonia nitrogen and organic matter). Discharged into the water, resulting in the rise of ammonia nitrogen, nitrite nitrogen and other harmful substances in the water body, thereby polluting the water quality, causing toxic effects on the aquaculture, and causing a large number of deaths of the aquaculture. Therefore, the detection and effective removal of ammonia nitrogen content in water is a key link in environmental monitoring of recirculating aquaculture, and is of great significance to aquaculture and ecological protection.

At present, in the process of factory farming, the most commonly used water quality treatment method is biological water purification technology, among which the biofilm method is widely used, which mainly relies on the microorganisms attached to the biological carrier or the surface of the filter material to degrade Water ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and other harmful substances, so as to achieve the function of water purification. However, this method is restricted by factors such as temperature, water alkalinity, long biofilm attachment and maturation time, slow construction of nitrifying bacteria system, and low biomass. In addition, the removal of ammonia nitrogen by physical methods such as adsorption technology has been widely used in small and medium-sized aquaculture, but the activated carbon adsorption technology also has the limitations of small specific surface area of the adsorbent, difficult regeneration, and high cost.

In recent years, _TiO2 photocatalysis has made great progress in the removal of organic and inorganic pollutants in the field of environmental protection, and is considered to be a promising deep purification technology for environmental pollution. TiO ₂ is widely used in photocatalytic treatment of organic or inorganic wastewater due to its high photostability, stable chemical properties, insoluble, non-toxic, low cost, and high efficiency. The main principle of this method is that when light with energy greater than or equal to the band gap energy of TiO ₂ is irradiated, TiO ₂ has a photoelectric effect, and absorbs photons to generate electron (e-)-hole (h ⁺ ) pairs, which pass through the band gap to the solution from the solution. And the species adsorbed on its surface transfers charges, holes capture the electrons in the adsorbate on the surface of the particle, so that the species is oxidized, and the electron acceptor accepts surface electrons and is reduced. However, due to the wide band gap (3.2 eV) of TiO ₂ , it can only be excited by ultraviolet rays with shorter wavelengths. In addition, due to the recombination of electrons and holes generated by photoexcitation, the photon quantum efficiency is very low. Therefore, the photocatalytic technology developed based on _TiO2 photocatalysis can promote the _TiO2 photogenerated electron-hole pair due to the electrochemical assisted method. The principle of this method is still based on the photoelectric effect, which mainly degrades the adsorbate on the surface of the catalyst by generating electron-holes. In addition, in TiO ₂ photoelectric catalysis technology, the commonly used radiation source is 254nm ultraviolet mercury lamp, but with the official entry into force of the "Minamata Convention", the application of ultraviolet mercury lamp will be further restricted.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a UVC-LED-DSA electrode coupling photoelectrochemical ammonia nitrogen synergistic removal system for the deficiencies of the existing aquaculture water ammonia nitrogen removal technology and TiO ₂ photoelectric catalysis technology.

In order to achieve the above object, the present invention adopts the following technical solutions to realize:

A UVC-LED-DSA electrode-coupled photoelectrochemical ammonia and nitrogen synergistic removal system, comprising a photoelectrochemical reactor, a DSA anode, a titanium cathode, a magnetic stirrer, a peristaltic pump, an anode gas outlet, a cathode gas outlet, a pH controller, a direct current Power supply, thermocouple, temperature control device, UVC-LED module (air-cooled cooling fan, heat sink, UVC-LED lamp beads), quartz glass plate. The UVC-LED module includes an air-cooled cooling fan, a heat sink, and a UVC-LED lamp bead; the DSA anode and the titanium cathode are arranged in the photoelectrochemical reactor; For the liquid containing ammonia nitrogen, the peristaltic pump is used to transport the liquid in the photoelectrochemical reactor to the temperature control device and then flow back into the reactor to form a cycle; the thermocouple is set in the temperature control device to measure the temperature of the liquid; The magnetic stirrer is used to fully mix the liquid in the photoelectrochemical reactor; the top of the photoelectrochemical reactor is provided with a sealing cover, the quartz glass plate is arranged in the center of the sealing cover, and the UVC-LED mold The group is fixed above the quartz glass plate (15), and can radiate the ultraviolet rays emitted by the UVC-LED lamp beads to the surface of the DSA anode and the titanium cathode and the solution between the two electrodes; the anode gas outlet and the cathode gas outlet are arranged on the sealing cover. The pH controller is used to adjust the pH of the liquid in the photoelectrochemical reactor, and the pH value is controlled between 4 and 8; The DC stabilized power supply is used to supply power to the DSA anode, titanium cathode and UVC-LED module; when the DSA anode and titanium cathode are energized with the DC stabilized power supply, the UVC-LED module (air-cooled cooling fan, heat sink, and heat sink) are turned on synchronously. and UVC-LED lamp beads), and then stimulate the photoelectric effect on the electrode surface of the photoelectrochemical reactor and the efficient active radical reaction in the solution phase.

In the above technical solution, further, the ratio of the electrode plate area of the titanium cathode to the DSA anode is 1:1. The DSA anode is a titanium-based ruthenium-iridium electrode, that is, the surface coating of the electrode contains RuO ₂ , IrO ₂ and TiO ₂ . The two electrodes are powered by a DC regulated power supply, and the voltage and current adjustment ranges are 0-30V and 0, respectively. ~5A.

Further, the driving voltage of the air-cooled cooling fan is DC 12V, and the UVC-LED lamp beads are 9 in total, (3*3) welded on the substrate and fixed on the surface of the heat sink.

Further, the peak wavelength of the UVC-LED lamp bead is 275nm, the half-peak width is 11nm, the driving voltage is 5.4V, the half-view angle is 120°, and the radiation power is 30mW.

Further, the photoelectrochemical reactor is made of quartz glass, and sodium chloride with a mass concentration of 0.5% to 2.0% is used as the electrolytic liquid in the photoelectrochemical reactor, and the hydraulic retention time of the liquid is 10min.

Further, the pH controller uses 1M HCl or 1M NaOH to adjust the pH of the liquid in the reactor to control the pH value between 4 and 8.

Further, in the photoelectrochemical reaction process, the liquid temperature in the photoelectrochemical reactor is 23±2°C.

Further, the UVC-LED-DSA electrode-coupled photoelectrochemical ammonia nitrogen oxidation synergistic removal system is mainly used for the treatment of aquaculture water bodies containing ammonia nitrogen, and the removal rate of ammonia nitrogen for ammonia nitrogen solutions of different concentrations within a certain reaction time. up to more than 95%.

The beneficial effects of the present invention are:

Aiming at the problem of removing pollutants such as low-concentration ammonia nitrogen in the industrialized circulating water treatment system, the invention adopts the method of combining 275nm UVC-LED and DSA anode for the first time, and the efficiency of removing ammonia nitrogen is higher; - The photoelectrochemical process coupled with LED and electrochemical oxidation is an environmentally friendly water treatment application technology, and its removal principle of ammonia nitrogen is different from the traditional _TiO2 photocatalytic technology. In this photoelectrochemical process, after ultraviolet radiation , the reaction system can generate non-selective hydroxyl radicals (HO·) and active chlorine components (Cl·, Cl ₂ · ^- , Cl ₂ , HOCl, ClO ^- ) in situ, which can extend the ammonia nitrogen oxidation reaction from the electrode surface to the solution phase, thereby improving the ammonia nitrogen removal efficiency and speeding up the treatment rate. As an emerging ultraviolet technology, UV-LED has a wider range of wavelengths than the UV mercury lamp. The present invention finds that the ultraviolet absorption of active chlorine to 275nm UVC-LED lamp beads is better than that of 254nm mercury lamp, that is, active chlorine More efficient free radicals can be generated under UVC-LED radiation.

The invention makes full use of the obvious advantages of UV-LED, such as compact structure, stable performance, low energy consumption and long life, as well as the characteristics of electrochemical advanced oxidation technology, and explores a new water treatment technology suitable for the treatment of ammonia nitrogen in water in industrialized circulating aquaculture. The constructed photoelectrochemical oxidation reaction system mainly consumes electricity, and can operate efficiently at a lower current density, with low operating cost, and the reaction device is simple in structure, small in size, simple in operation and easy to maintain; the DSA anode used has good The electrocatalytic activity and stability, corrosion resistance, electrical conductivity and processability are good, which can greatly improve the service life of the system; in addition, the photoelectrochemical oxidation reaction system mainly removes pollutants such as ammonia nitrogen and other pollutants quickly and efficiently by generating active radical components. Green, environmentally friendly and other characteristics.

Description of drawings

Fig. 1 is the structural representation of the system of the present invention;

2 is a schematic structural diagram of a UVC-LED lamp bead array in the system of the present invention;

Fig. 3 is the radiation spectrum diagram of UVC-LED lamp beads in the system of the present invention;

Fig. 4 is the degradation effect diagram of the system of the present invention to ammonia nitrogen in 45min time;

5 is a photocurrent comparison diagram of DSA electrode and TiO ₂ electrode under different scanning voltages in the process of ammonia nitrogen oxidation in the system of the present invention;

Among them, (1) photoelectrochemical reactor, (2) DSA anode, (3) titanium cathode, (4) magnetic stirrer, (5) peristaltic pump, (6) anode gas outlet, (7) cathode gas outlet, ( 8) pH controller, (9) DC stabilized power supply, (10) thermocouple, (11) temperature control device, (12) air cooling fan, (13) heat sink, (14) UVC-LED lamp beads, (15) Quartz glass plate.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments.

As shown in Figures 1 to 3, a UVC-LED-DSA electrode coupled photoelectrochemical ammonia nitrogen oxide synergistic removal system is shown.

Fig. 1 is the structural schematic diagram of the system of the present invention, including photoelectrochemical reactor 1, DSA anode 2, titanium cathode 3, magnetic stirrer 4, peristaltic pump 5, anode gas outlet 6, cathode gas outlet 7, pH controller 8, DC Regulated power supply 9 , thermocouple 10 , temperature control device 11 , air cooling fan 12 , heat sink 13 , UVC-LED lamp beads 14 , and quartz glass plate 15 . The photoelectrochemical reactor 1 is provided with a water inlet and a water outlet, and the liquid in the photoelectrochemical reactor 1 is transported to the temperature control device 11 by the peristaltic pump 5 to maintain the reaction in the reactor at a constant temperature of 23 ± 2 °C. The magnetic stirrer 4 fully mixes the liquid in the photoelectrochemical reactor 1 to maintain rapid mass transfer in the photoelectrochemical reactor 1; the thermocouple 10 is arranged in the temperature control device 11 for temperature measurement of the liquid ;The DC stabilized power supply 9 adopts 0~30V; 0~5A connects the DSA anode 2 and the titanium cathode 3, and supplies power to the UVC-LED module, and simultaneously turns on the UVC-LED module air cooling fan 12, heat sink 13, UVC-LED lamp beads 14, ultraviolet rays can be radiated to the surface of the cathode and the anode and the solution between the two electrodes through the quartz glass plate 15 in the center of the top sealing cover of the photoelectrochemical reactor 1, and further stimulate the photoelectric effect and the solution on the electrode surface of the photoelectrochemical reactor. Effective free radical reaction in the phase, at the same time, the pH controller 8 is used to adjust the solution in the reactor to maintain a suitable pH value in the range of 4-8.

As shown in FIG. 2 , there are 9 UVC-LED lamp beads 14 in a 3*3 array. All the UVC-LED lamp beads 14 are welded on the substrate and fixed on the surface of the heat sink 13 .

3 is the radiation spectrum diagram of the UVC-LED lamp beads 14 in the system of the present invention, the peak wavelength of the UVC-LED lamp beads 14 is 275 nm, the half-peak width is 11 nm, the driving voltage is 5.4V, and the half-angle of view is 120° , the radiation power is 30mW.

Below, the technical scheme of the present invention will be described by specific embodiments:

Example

The water body containing 10mg/L ammonia nitrogen is treated by the system of the invention, the water body salinity is 5‰, the water body circulation flow rate is 200mL/min, the water body temperature is maintained at 23±2°C, and the pH is maintained at 4-8. The liquid in the photoelectrochemical reactor 1 was treated by a two-electrode system. The anode was a titanium-based ruthenium-iridium DSA anode, and the cathode was a titanium electrode. The size of the electrode sheet was 10cm*6cm, the thickness of the electrode was 0.1cm, and the electrode current density was 3mA/ cm ² , UVC-LED lamp beads 14 are used to irradiate the photoelectrochemical reactor 1 with ultraviolet radiation, the radiation intensity is 2.2mW/cm ² , and 9 UVC-LED lamp beads 14 (3*3 array) are welded on the substrate (size is : 28mm*28mm), the centerline spacing of two adjacent UVC-LED lamp beads 14 is 7mm, the peak wavelength of the lamp beads is 275nm, the half-peak width is 11nm, the driving voltage is 5.4V, and the half-angle of view is 120°. The electrochemical system runs synchronously with the UVC-LED module. The treatment time for the water body is 45min, and at 35min, the removal rate of ammonia nitrogen in the water body is close to 100%, as shown in Figure 4, the rapid and efficient removal of low-concentration ammonia nitrogen can be achieved.

Figure 5 is the photocurrent comparison diagram of DSA electrode and TiO ₂ electrode under different scanning voltages in the process of ammonia nitrogen oxidation of the system of the present invention; it can be seen from the figure that in the scanning voltage range of -1 ~ 1.3V, under the condition of higher potential, The photocurrent in the coupling process of 275nm UV-LED and DSA electrode is obviously better than that of TiO2 photocatalytic process excited by 254nm UV mercury lamp, which further illustrates the removal of ammonia nitrogen by the photoelectrochemical process of UVC-LED-DSA electrode coupling mediated by activity. Better results.

The above-mentioned embodiments are only to illustrate the technical conception, characteristics and advantages of the present invention, and the purpose thereof is to enable those who are familiar with the technology to understand the content of the present invention and implement it, and cannot limit the scope of protection of the present invention with this. Equivalent changes or modifications made in the spirit of the invention shall all be included within the protection scope of the present invention.

Claims (9)

1. A photoelectrochemistry oxidation ammonia nitrogen collaborative removal system coupled with a UVC-LED-DSA electrode is characterized in that: the system comprises a photoelectrochemical reactor (1), a DSA anode (2), a titanium cathode (3), a magnetic stirrer (4), a peristaltic pump (5), an anode gas outlet (6), a cathode gas outlet (7), a pH controller (8), a direct current stabilized voltage power supply (9), a thermocouple (10), a temperature control device (11), a UVC-LED module and a quartz glass plate (15); the UVC-LED module comprises an air-cooling heat dissipation fan (12), a heat dissipation sheet (13) and UVC-LED lamp beads (14); the DSA anode (2) and the titanium cathode (3) are arranged in the photoelectrochemical reactor (1); the photoelectrochemical reactor (1) is filled with liquid containing ammonia nitrogen to be treated, the peristaltic pump (5) is used for inputting the liquid containing ammonia nitrogen to be treated into the temperature control device (11) for temperature adjustment, and the liquid flows back to the photoelectrochemical reactor (1) to form a cycle; the thermocouple (10) is arranged in the temperature control device (11) and is used for measuring the temperature of the liquid; the magnetic stirrer (4) is used for fully mixing the liquid in the photoelectrochemical reactor (1); the top of the photoelectrochemical reactor (1) is provided with a sealing cover, the quartz glass plate (15) is arranged in the center of the sealing cover, the UVC-LED module is fixed above the quartz glass plate (15) and can radiate ultraviolet rays emitted by UVC-LED lamp beads (14) to the surfaces of a DSA anode (2) and a titanium cathode (3) and a solution between the two electrodes; the anode gas outlet (6) and the cathode gas outlet (7) are arranged on the sealing cover and are used for discharging gas generated after ammonia nitrogen oxidation; the pH controller (8) is used for adjusting the pH of the liquid in the photoelectrochemical reactor (1); the direct current stabilized power supply (9) is used for supplying power to the DSA anode (2), the titanium cathode (3) and the UVC-LED module.

2. The photoelectrochemical ammonia nitrogen oxide synergistic removal system coupled with the UVC-LED-DSA electrode according to claim 1, wherein: the area ratio of the titanium cathode to the DSA anode is 1: 1; the DSA anode (2) is a titanium-based ruthenium iridium electrode, namely the surface coating of the electrode contains RuO₂、IrO₂And TiO₂。

3. The photoelectrochemical ammonia nitrogen oxide synergistic removal system coupled with the UVC-LED-DSA electrode according to claim 1, wherein: the voltage and current adjusting ranges of the DSA anode (2) and the titanium cathode (3) are 0-30V and 0-5A respectively.

4. The photoelectrochemical ammonia nitrogen oxide synergistic removal system coupled with the UVC-LED-DSA electrode according to claim 1, wherein: the driving voltage of the air-cooled heat dissipation fan (12) is DC 12V; 9 UVC-LED lamp pearls (14), 3 x 3 weld on the base plate and fix on fin (13) surface.

5. The photoelectrochemical ammonia nitrogen oxide synergistic removal system coupled with the UVC-LED-DSA electrode according to claim 1, wherein: the peak wavelength of the UVC-LED lamp bead (14) is 275nm, the half-peak width is 11nm, the driving voltage is 5.4V, the half visual angle is 120 degrees, and the radiation power is 30 mW.

6. The photoelectrochemical ammonia nitrogen oxide synergistic removal system coupled with the UVC-LED-DSA electrode according to claim 1, wherein: the photoelectrochemical reactor (1) is made of quartz glass, sodium chloride with the mass concentration of 0.5-2.0% is used as electrolytic liquid in the photoelectrochemical reactor (1), and the hydraulic retention time of the liquid is 10 min.

7. The photoelectrochemical ammonia nitrogen oxide synergistic removal system coupled with the UVC-LED-DSA electrode according to claim 1, wherein: the pH controller (8) adjusts the pH of the liquid in the photoelectrochemical reactor (1) through 1M HCl or 1M NaOH, and controls the pH value to be 4-8.

8. The photoelectrochemical ammonia nitrogen oxide synergistic removal system coupled with the UVC-LED-DSA electrode according to claim 1, wherein: the liquid temperature in the photoelectrochemical reactor (1) is 23 +/-2 ℃.

9. The synergistic UVC-LED-DSA electrode-coupled photoelectrochemical ammonia nitrogen oxide removal system according to any one of claims 1 to 8, wherein: the system is used for treating the aquaculture water containing ammonia nitrogen.

Images