Method for treating high-chloride-ion tetracycline hydrochloride wastewater by coupling nitrogen self-doped ruthenium-based biochar with electrodialysis

Abstract

The invention discloses a method for treating high-chloride-ion tetracycline hydrochloride wastewater by coupling nitrogen self-doped ruthenium-based charcoal with electrodialysis. Aiming at the problems that the conductivity of a light chamber is reduced and tetracycline hydrochloride is polluted when high-chloride-ion tetracycline hydrochloride wastewater is treated by an electrodialysis technology, a nitrogen self-doped ruthenium-based charcoal coupled electrodialysis technology system is constructed, and a high-chloride-ion tetracycline hydrochloride wastewater treatment and resource utilization technology is established; the synchronous desalination and pollution reduction treatment of the high-salinity organic wastewater is realized. The nitrogen self-doped ruthenium-based biochar coupled electrodialysis treatment system constructed by the invention can solve the problem of low conductivity in the process of separating salt by electrodialysis, and the chloride ions in the water body are utilized to degrade organic pollutants in the light chamber, so that the resource utilization efficiency of the high-chloride-ion tetracycline hydrochloride wastewater is guaranteed.

Description

Technical Field

[0001] The invention relates to a method for simultaneously dechlorinating water and degrading tetracycline hydrochloride, in particular to an improved electrodialysis desalination chamber reaction system for simultaneously desalting and reducing pollution of high-salinity organic wastewater. Background Art

[0002] With the increasing demand for seafood in my country, the scale of mariculture is also expanding. The total amount of mariculture wastewater exceeds 5 billion tons each year. The high-salt characteristics increase the difficulty of treating mariculture wastewater. On the other hand, in order to ensure the safety of seafood supply, antibiotics are added to feed to eliminate pathogenic bacteria, prevent seafood diseases, and increase its yield. Tetracycline hydrochloride is the most widely used antibiotic in mariculture, which can treat fish vibriosis, shrimp blindness, shrimp sepsis and other diseases during mariculture. However, only a small part of the tetracycline hydrochloride added to seafood aquaculture water can be used, and more than 75% of the tetracycline hydrochloride will remain in the water, resulting in excessive antibiotics in the water environment and causing environmental pollution. The tetracycline hydrochloride remaining in the water can not only cause deformities or death of algae, fish and other aquatic organisms, but also induce the production of drug-resistant bacteria, directly threatening human health. Therefore, conducting research on high-chloride tetracycline hydrochloride wastewater as the target polluted water body can not only provide a reference for the treatment of marine aquaculture wastewater, but also help to solve the urgent need for resource utilization of high-salt organic wastewater.

[0003] As a common desalination technology, electrodialysis has the advantage of being able to operate at room temperature and pressure, avoiding the energy consumption caused by changing temperature and pressure, and is widely used in the desalination of high-salt organic wastewater. However, when electrodialysis technology is used to treat high-chloride ion tetracycline hydrochloride wastewater, the conductivity of the dilute chamber will decrease due to the continuous transfer of chloride ions to the concentrated chamber, aggravating the influence of concentration polarization; in addition, tetracycline hydrochloride in the dilute chamber will not only cause membrane pollution, but also increase the difficulty and cost of subsequent treatment. Therefore, how to alleviate the concentration polarization phenomenon aggravated by the decrease in conductivity of the dilute chamber during electrodialysis desalination, and how to solve the membrane pollution and effluent organic load problems caused by organic pollutants in the dilute chamber are the difficulties of current research.

[0004] In order to solve the concentration polarization problem aggravated by the low conductivity of the electrodialysis desalination chamber, granular electrode materials with conductivity, catalysis and chlorine evolution selectivity can be added to the desalination chamber to stabilize the conductivity of the desalination chamber and improve the degradation capacity of organic pollutants in the desalination chamber. Biochar itself is conductive and can stabilize the conductivity of the desalination chamber. Nitrogen doping improves the electrochemical and catalytic properties of biochar. The electronegativity of nitrogen atoms is greater than that of carbon atoms. The performance of biochar is improved by the trend of electron transfer from carbon atoms to nitrogen atoms. Under the concept of green chemistry, various nitrogen self-doped biochars with excellent performance can be prepared without the need for an external nitrogen source using nitrogen-rich biomass resources. Tea residue itself has a high nitrogen content, and a high mass ratio of nitrogen can also be detected in biochar prepared with tea residue as raw material. Using tea residue, which is rich in nitrogen, as raw material, it has the potential to prepare nitrogen self-doped biochar materials without the need for an external nitrogen source. Ruthenium oxide, as a precious metal oxide, has extremely high catalytic activity, mainly due to its excellent proton transfer ability and excellent reversible redox transformation performance. Studies have shown that using ruthenium oxide as an electrode component can improve the selectivity of the chlorine evolution reaction. Therefore, using nitrogen self-doped biochar prepared from tea residue as a carrier material and loading ruthenium oxide with chlorine evolution selectivity as an active substance, a nitrogen self-doped ruthenium-based biochar with good conductivity, catalytic ability, and chlorine evolution selectivity can be obtained, which can stabilize the conductivity of the electrodialysis dilution chamber and simultaneously degrade tetracycline hydrochloride in high-chloride ion tetracycline hydrochloride wastewater. Summary of the invention

[0005] In order to solve the problems of decreased conductivity in the dilute chamber, membrane pollution caused by organic pollutants and effluent organic load during electrodialysis treatment of high-chloride ion tetracycline hydrochloride wastewater, the present invention provides a nitrogen self-doped ruthenium-based biochar coupled electrodialysis reaction method that can be used for simultaneous desalination and pollution reduction of high-chloride ion tetracycline hydrochloride wastewater.

[0006] The technical solution adopted by the present invention is as follows.

[0007] The present invention provides a nitrogen self-doped ruthenium-based biochar coupled electrodialysis method for simultaneous desalination and pollution reduction of high-chloride ion tetracycline hydrochloride wastewater, and the specific steps are as follows:

[0008] (1) 5.0 g of tea residue and KOH activator were mixed in 50 mL of deionized water in a ratio of 1:2, 1:1 and 2:1, respectively. The mixture was magnetically stirred for 4 h to make it fully mixed. The activated tea residue was placed in a tubular furnace and dried at 80 °C. The dried tea residue was placed in a tubular furnace, which was filled with nitrogen and carbonized at 300-600 °C for 0.5-2.0 h. The biochar was repeatedly washed with ultrapure water and dried in an oven to obtain nitrogen self-doped tea residue biochar.

[0009] (2) Take 5 g of nitrogen-doped tea residue biochar and put it into a water bath; pour 200 mL of nitrogen-doped tea residue biochar with concentrations of 0.5, 1, 2, and 4 mg L -1 The ruthenium chloride solution was added, the temperature of the water bath was controlled at 40 °C and the soaking time was 48 h. The biochar particles after soaking were taken out and placed in a muffle furnace filled with nitrogen. The temperature of the muffle furnace was adjusted to 300-600 °C and heated for 2-4 h to obtain nitrogen self-doped ruthenium-based tea residue biochar.

[0010] (3) The electrodialysis reactor uses a membrane stack (10–30 pairs of membranes). The electrodialysis cation membrane is made of sulfonated resin, the anion membrane is made of quaternized resin, the electrode materials at both ends are ruthenium-iridium electrodes, the reaction voltage is 5–25 V, and the initial NaCl concentration of the fresh water is 10–30 g L -1 The initial tetracycline hydrochloride concentration in the freshwater chamber was 0.05–10 g L -1 The initial NaCl concentration in the concentration chamber was 0–20 g L -1 , the electrolyte in the electrode chamber is 20 g L -1 Na 2 SO 4 .

[0011] (4) Nitrogen self-doped ruthenium-based tea residue biochar granule electrodes were added to different dilute chambers, and quartz sand and nitrogen self-doped ruthenium-based tea residue biochar granule electrodes were placed in the dilute chamber in different proportions. The ratio of quartz sand to granule electrodes was set to 1:5, 1:3, 1:2, 1:1, 2:1, 3:1, and only nitrogen self-doped ruthenium-based tea residue biochar granule electrodes were placed. The water circulation flow rates of the dilute chamber and the concentrated chamber were set to 4–20 L h -1 The water circulation rate in the polar chamber is 25 L h -1 .

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: the nitrogen self-doped ruthenium-based biochar coupled electrodialysis system constructed by the present invention adds a nitrogen self-doped ruthenium-based biochar particle electrode with conductivity, electrocatalytic activity and chlorine evolution selectivity into the electrodialysis desalination chamber, which can stabilize the conductivity of the electrodialysis desalination chamber and efficiently convert chloride ions into active substances to degrade tetracycline hydrochloride during the desalination process, which not only ensures the electrodialysis desalination efficiency, but also can simultaneously degrade organic pollutants in the desalination chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is the preparation process of nitrogen self-doped ruthenium-based tea residue biochar particle electrode.

[0014] Figure 2The reaction principle is to add nitrogen self-doped ruthenium-based biochar as a particle electrode to the electrodialysis dilute chamber. Among them, the solution in the dilute chamber and the concentrated chamber is injected and extracted by a peristaltic pump; the concentrated chamber in the reactor refers to the reaction area where anions and cations continuously enter during the reaction and the concentration continues to increase; the dilute chamber in the reactor refers to the reaction area where anions and cations continuously flow out during the reaction and the concentration continues to decrease; the dilute chamber causes a sharp drop in ion concentration due to the outflow of a large number of anions and cations, and the conductivity of the entire electrodialysis system decreases, and the desalination effect will also decrease; in addition, tetracycline hydrochloride in the dilute chamber will also cause membrane pollution, increasing the difficulty and cost of subsequent treatment; the particle electrode with biochar as a carrier added to the dilute chamber can weaken the concentration polarization effect of the dilute chamber and stabilize the conductivity of the dilute chamber. The preparation of the particle electrode by nitrogen self-doping can improve the electrocatalytic activity of the electrode itself, and the loading of ruthenium-based materials with chlorine evolution selectivity can improve the ability of the particle electrode to convert chloride ions into active substances, thereby improving the ability of the dilute chamber of the electrodialysis reaction system to simultaneously remove chloride ions and tetracycline hydrochloride.

[0015] Figure 3 It is the change of tetracycline hydrochloride concentration in the dilute chamber of the nitrogen self-doped ruthenium-based biochar coupled electrodialysis reaction system in Example 1.

[0016] Figure 4 It is the change in chloride ion concentration in the desalination chamber of the nitrogen self-doped ruthenium-based biochar coupled electrodialysis reaction system in Example 2. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0018] like Figure 2 As shown, Figure 2 The reaction principle is to add nitrogen self-doped ruthenium-based biochar as a particle electrode to the electrodialysis dilution chamber. During the reaction, the anions and cations in the dilution chamber will enter the concentration chamber, causing the conductivity of the entire electrodialysis system to decrease, thereby affecting the desalination effect; in addition, tetracycline hydrochloride in the dilution chamber will also cause membrane pollution, increasing the difficulty of effluent treatment; adding a particle electrode with biochar as a carrier in the dilution chamber can weaken the concentration polarization effect of the dilution chamber and stabilize the conductivity of the dilution chamber. The preparation of particle electrodes by nitrogen self-doping can improve the electrocatalytic activity of the electrode itself. Loading ruthenium-based materials with chlorine selectivity can improve the ability of particle electrodes to convert chloride ions into active substances, thereby improving the ability of the dilution chamber of the electrodialysis reaction system to simultaneously remove chloride ions and tetracycline hydrochloride.

[0019] Example 1

[0020] (1) 5.0 g of tea residue and KOH activator were mixed in 50 mL of deionized water in a ratio of 1:2, and the mixture was magnetically stirred for 4 h to be fully mixed. The activated tea residue was placed in a tubular furnace and dried at 80 °C. The dried tea residue was placed in a tubular furnace, which was filled with nitrogen and carbonized at 300 °C for 1.5 h. The biochar was repeatedly washed with ultrapure water and dried in an oven to obtain nitrogen self-doped tea residue biochar.

[0021] (2) Take 5 g of nitrogen self-doped tea residue biochar and put it into a water bath. Pour 200 mL of 4 mg L -1 The ruthenium chloride solution was added, the temperature of the water bath was controlled at 40°C and soaked for 48 hours, the soaked biochar particles were taken out and placed in a muffle furnace filled with nitrogen, the temperature of the muffle furnace was adjusted to 300°C and heated for 2 hours to obtain nitrogen self-doped ruthenium-based tea residue biochar.

[0022] (3) The electrodialysis reactor uses a membrane stack (10 pairs of membranes). The electrodialysis positive membrane is made of sulfonated resin, the negative membrane is made of quaternized resin, the electrode materials at both ends are ruthenium iridium electrodes, the reaction voltage is 10 V, and the initial NaCl concentration of the fresh water is 10 g / L. -1 The initial concentration of tetracycline hydrochloride in the freshwater chamber was 1 g L -1 The initial NaCl concentration in the concentration chamber is 10 g L -1 , the electrolyte in the electrode chamber is 20 g L -1 Na 2 SO 4 .

[0023] (4) Nitrogen self-doped ruthenium-based tea residue biochar granule electrodes were added to different dilute chambers, and quartz sand and nitrogen self-doped ruthenium-based tea residue biochar granule electrodes were placed in the dilute chamber in different proportions. The ratio of quartz sand to granule electrodes was set to 1:1, and only nitrogen self-doped ruthenium-based tea residue biochar granule electrodes were placed. The water circulation flow rate of the dilute chamber and the concentrated chamber was set to 10 L h -1 The water circulation rate in the polar chamber is 25 L h -1 .

[0024] In Example 1, the nitrogen self-doped biochar prepared by carbonizing at 300°C for 1.5 h has a high nitrogen content. 200 mL of the biochar was poured into the mixture with a concentration of 4 mg L -1 The ruthenium chloride solution can increase the loading amount of ruthenium oxide, thereby obtaining a particle electrode with strong electrocatalytic and chlorine evolution performance, which is suitable for the treatment of water bodies with high chloride ion content and high tetracycline hydrochloride concentration.

[0025] Example 2

[0026] (1) 5.0 g of tea residue and KOH activator were mixed in 50 mL of deionized water in a ratio of 2:1, and the mixture was magnetically stirred for 4 h to be fully mixed. The activated tea residue was placed in a tubular furnace and dried at 80 °C. The dried tea residue was placed in a tubular furnace, which was filled with nitrogen and carbonized at 500 °C for 2.0 h. The mixture was repeatedly washed with ultrapure water and dried in an oven to obtain nitrogen self-doped tea residue biochar.

[0027] (2) Take 5 g of nitrogen self-doped tea residue biochar and put it into a water bath. Pour 200 mL of 4 mg L -1 The ruthenium chloride solution was added, the temperature of the water bath was controlled at 40°C and soaked for 48 hours, the biochar particles after soaking were taken out and placed in a muffle furnace filled with nitrogen, the temperature of the muffle furnace was adjusted to 500°C and heated for 3 hours to obtain nitrogen self-doped ruthenium-based tea residue biochar.

[0028] (3) The electrodialysis reactor uses a membrane stack (30 pairs of membranes). The electrodialysis positive membrane is made of sulfonated resin, the negative membrane is made of quaternized resin, the electrode materials at both ends are ruthenium iridium electrodes, the reaction voltage is 25 V, and the initial NaCl concentration of the fresh water is 30 g / L -1 The initial concentration of tetracycline hydrochloride in the freshwater chamber was 1 g L -1 The initial NaCl concentration in the concentration chamber is 20 g L -1 , the electrolyte in the electrode chamber is 20 g L -1 Na 2 SO 4 .

[0029] (4) Nitrogen self-doped ruthenium-based tea residue biochar granule electrodes were added to different dilute chambers, and quartz sand and nitrogen self-doped ruthenium-based tea residue biochar granule electrodes were placed in the dilute chamber in different proportions. The ratio of quartz sand to granule electrodes was set to 1:1, and only nitrogen self-doped ruthenium-based tea residue biochar granule electrodes were placed. The water circulation flow rate of the dilute chamber and the concentrated chamber was set to 20 L h -1 The water circulation rate in the polar chamber is 25 L h -1 .

[0030] like Figure 3 and Figure 4 As shown, the rice husk control group is the treatment effect of replacing rice husk biochar with ruthenium-based tea residue biochar doped with nitrogen in the dilute chamber; wherein, the preparation conditions of rice husk are: heating under nitrogen conditions, the heating temperature is 500°C, and the heating time is 2h. In Example 2, the water circulation flow rate of the reactor membrane stack, the dilute chamber and the concentrated chamber is increased, and the processing capacity per unit time can be increased, which is suitable for pollution scenarios with large demand for high chloride ion tetracycline hydrochloride wastewater treatment.

[0031] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for treating high-chloride tetracycline hydrochloride wastewater by nitrogen self-doped ruthenium-based biochar coupled with electrodialysis, characterized in that: The specific steps are as follows: 5.0 g of tea residue and KOH activator were mixed in 50 mL of deionized water in a ratio of 1:2, 1:1 and 2:1, respectively. The mixture was magnetically stirred for 4 h to be fully mixed. The activated tea residue was placed in a tube furnace and dried at 80 °C. The dried tea residue was placed in a tube furnace, which was filled with nitrogen. The temperature was maintained at 300-600 °C for carbonization for 0.5-2.0 h, and the mixture was repeatedly washed with ultrapure water and dried in an oven to obtain nitrogen self-doped tea residue biochar. 5 g of nitrogen self-doped tea residue biochar was put into a water bath, and 200 mL of 0.5, 1, 2, and 4 mg L -1 The ruthenium chloride solution was added, the temperature of the water bath was controlled at 40 °C for 48 h, the biochar particles after soaking were taken out and placed in a muffle furnace filled with nitrogen, the temperature of the muffle furnace was adjusted to 300-600 °C and heated for 2-4 h to obtain nitrogen self-doped ruthenium-based tea residue biochar; the electrodialysis-three-dimensional electrode reactor used a group of membrane stacks (10 pairs of membranes), the electrodialysis positive membrane material was sulfonated resin, the negative membrane was quaternized resin, the electrode materials at both ends were ruthenium iridium electrodes, the reaction voltage was 5-25 V, and the initial NaCl concentration of the fresh water inlet was 10-30 g L -1 The initial concentration of tetracycline hydrochloride in the freshwater chamber is 0.05-10 g L -1 The initial NaCl concentration in the concentration chamber is 0-20 g L -1 , the electrolyte in the electrode chamber is 20 g L -1 of Na2SO4; the nitrogen self-doped ruthenium-based tea residue biochar particle electrodes were added to different dilute chambers, and quartz sand and nitrogen self-doped ruthenium-based tea residue biochar particle electrodes were placed in the dilute chamber in different proportions, and the ratio of quartz sand to particle electrodes was set to 1:5, 1:3, 1:2, 1:1, 2:1, 3:1 and only nitrogen self-doped ruthenium-based tea residue biochar particle electrodes were placed, and the water circulation flow rate of the dilute chamber and the concentrated chamber was set to 4-20Lh -1 The water circulation rate in the polar chamber is 25 L h -1 Adding nitrogen self-doped ruthenium-based biochar to the electrodialysis desalination chamber can stabilize the conductivity of the desalination chamber and avoid the reduction of desalination efficiency caused by the sharp drop in the conductivity of the desalination chamber during the electrodialysis desalination process. The biomass carbon-based material can make the particle electrode conductive, nitrogen self-doping can make the particle electrode obtain better electrocatalytic performance, and the loaded ruthenium-based material can make the particle electrode improve the chlorine evolution selectivity. The particle electrode added to the desalination chamber can stabilize the conductivity of the desalination chamber and use the chloride ions in the desalination chamber to degrade tetracycline hydrochloride, thereby achieving the purpose of simultaneous desalination and degradation of organic pollutants.

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