CN115928110A - Hydrogenation dechlorination method of high-concentration chlorinated aromatic compound - Google Patents

Abstract

The invention discloses a method for hydrogenation dechlorination of high-concentration chlorinated aromatic compounds. The method comprises the steps of adding high-concentration chlorinated aromatic compounds into an alkaline solution to obtain catholyte, using alkaline aqueous solution as anolyte, and modifying electrodes with palladium As the cathode, stainless steel is used as the anode, and the electrolysis reaction is carried out in the electrolytic cell separated by the ion exchange membrane. After the electrolysis reaction is completed, the electrolyte solution of the dechlorination compound is obtained, and the electrolyte solution is separated and purified to obtain the dechlorination compound. The palladium modified electrode adopts Prepared by cathode deposition method. The hydrodechlorination method of high-concentration chlorinated aromatic compounds provided by the present invention simultaneously realizes high reactant concentration, high space-time yield, high selectivity, high current efficiency and high current density, and can not only greatly reduce the amount of catalyst palladium and It reduces electrolysis energy consumption and produces high value-added products in the process of chlorinated organic matter treatment.

Description

A method for dechlorinating high-concentration chlorinated aromatic compounds

Technical Field

The invention belongs to the field of water pollution treatment, and particularly relates to a hydrogenation dechlorination method for high-concentration chlorinated aromatic compounds.

Background Art

Chlorinated aromatic compounds (CAPs) are an important class of persistent organic compounds that are widely present in industrial wastewater produced in the synthesis of pesticides, medicines, dyes, etc. They are very toxic to organisms and the environment. Removing chlorine atoms from CAPs to generate less toxic aromatics or alkanes is a common environmental remediation route. Palladium-catalyzed electrochemical hydrogenation has attracted much attention due to its advantages of not requiring the addition of expensive or hazardous reducing agents, mild reaction conditions, and high reaction selectivity. Various CAPs in wastewater can be converted into the same substance through palladium-catalyzed selective hydrogenation and dechlorination reactions (for example, chlorophenols can be dechlorinated into phenol, chlorophenoxyacetic acids can be dechlorinated into phenoxyacetic acid, and chloropicolinic acid can be dechlorinated into picolinic acid). Highly chemically selective hydrogenation and dechlorination methods are expected to achieve the transformation of CAPs in industrial wastewater into treasure.

Unfortunately, most of the current palladium-catalyzed electrochemical hydrogenation dechlorination reaction research focuses on the treatment of CAPs at low concentrations (mg/L level) in water bodies, and requires a very high amount of palladium catalyst. For example, the invention patent application with application number 200910237763.7 discloses a palladium catalyst for treating chlorinated organic matter in water and a preparation method thereof, which uses electrochemical reduction oxidation coupling multifunctional palladium-supported catalyst as the catalyst of the electrochemical cathode. Although it has a reduction dechlorination effect and fully utilizes the reduction effect of the cathode to improve the electrochemical treatment efficiency of chlorinated organic matter in water, it still has the above-mentioned shortcomings. This leads to a series of problems such as high catalyst cost per unit CAPs treatment amount, low current efficiency, low current density, and difficulty in recovering dechlorinated products, making it difficult to generate economic benefits. Therefore, it is of great application value to invent a hydrogenation dechlorination method with low loading and high conversion rate and high selectivity for high-concentration CAPs.

Summary of the invention

In order to solve the above technical problems, the present invention provides a method for hydrogenation dechlorination of high-concentration chlorinated aromatic compounds, wherein a variety of CAPs are added to an alkaline solution to obtain a high-concentration electrolytic reaction solution, and then a palladium-modified conductive material is used as a cathode and a chemically inert conductive material is used as an anode to carry out an electrolytic reaction in an electrolytic cell separated by an ion exchange membrane, and various CAPs can achieve high current efficiency, high current density, high space-time yield and high selectivity for dechlorination. The present invention can effectively solve the problems of low reactant concentration, low palladium utilization, low current efficiency and low current density in the existing palladium-catalyzed dechlorination technology.

The technical solution adopted by the present invention is as follows:

The present invention provides a method for hydrogenating and dechlorinating chlorinated aromatic compounds. The method comprises the following steps: adding the chlorinated aromatic compound represented by formula (I) into an alkaline aqueous solution to obtain a cathode liquid; using the alkaline aqueous solution as an anode liquid, a palladium-modified electrode as a cathode, and stainless steel as an anode; and performing an electrolytic reaction in an electrolytic cell separated by an ion exchange membrane; obtaining an electrolyte containing a dechlorinated compound represented by formula (II) after the electrolytic reaction is completed; and separating and purifying the electrolyte to obtain the dechlorinated compound represented by formula (II).

XRClnXRHn

(Ⅰ) (Ⅱ)

In formula (I), R is a single benzene ring or a single pyridine ring; X is a hydroxyl group, a carboxyl group or an acetoxy group, and n is a positive integer between 1 and 5; R, X and n in formula (II) are the same as those in formula (I).

The concentration of the chlorinated aromatic compound represented by formula (I) in the cathode liquid is 5 to 300 g/L.

The chlorinated aromatic compound represented by formula (I) is one or more of chloropicolinic acid, chlorophenol, chlorobenzoic acid and chlorophenoxyacetic acid.

The pH of the cathode liquid is in the range of 10-14, preferably 12-14, more preferably 14.

The pH value of the anolyte is 13-14, preferably 12-14, more preferably 14.

The conditions for the electrolysis reaction are: current density of 1-20 A/dm ² , preferably 2-15 A/dm ² , more preferably 2-12.5 A/dm ² , temperature of 0-100°C, preferably 10-80°C, more preferably 20-70°C.

The alkaline aqueous solution is prepared by mixing water and a supporting electrolyte; the supporting electrolyte is one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, lithium carbonate, tetramethylammonium hydroxide, tetraethylammonium hydroxide or tetrapropylammonium hydroxide, preferably sodium hydroxide; the concentration of the supporting electrolyte in the electrolyte is 0.1 to 2.0 mol/L, preferably 1 to 2.0 mol/L.

The anode may be in the form of a plate, a rod, a wire, a mesh, a net, a foam, a wool or a sheet, preferably in the form of a plate.

The electrolytic reaction of the present invention can be carried out intermittently or in a continuous or semi-continuous manner. The electrolyzer can be a stirred tank containing electrodes or a flow electrolyzer of any conventional design. The electrolyzer can be a diaphragm electrolyzer or a diaphragm-free electrolyzer, preferably an electrolyzer with a diaphragm.

The anode reaction of the present invention can be an oxygen evolution reaction that releases oxygen, or it can be a hydrogen oxidation reaction including the release of chlorine molecules and bromine molecules, the production of carbon dioxide through the oxidation of protective substances such as formate or oxalate, or the formation of valuable by-products through the oxidation of organic reactants, preferably the oxygen evolution reaction.

The palladium modified electrode is prepared by cathode deposition method; further, the palladium modified electrode is prepared by the following specific method:

(1) preparing an electrode substrate: using a conductive material as an electrode substrate, first cleaning the grease on the surface of the substrate with an organic solvent, and then etching the oxide layer on the surface of the substrate with an acidic aqueous solution to obtain a treated electrode substrate;

(2) Cathode deposition: The treated electrode substrate obtained in step (1) is used as the cathode, the inert material is used as the anode, the aqueous solution containing polyvinyl pyrrolidone, sodium sulfate and palladium salt is used as the cathode electrolyte, and the aqueous solution of sodium sulfate is used as the anode electrolyte, and a palladium modified electrode with a palladium loading of 0.5 to 5 g/ ^m2 is prepared by cathode deposition method.

In step (1), the electrode substrate is selected from metals such as nickel, stainless steel, titanium, and silver, or carbon such as graphite, carbon fiber, carbon felt, and glassy carbon, the organic solvent is one or more of acetone, ethanol, methanol, and ether, and the acidic aqueous solution is one or more of aqueous solutions of sulfuric acid, hydrochloric acid, and nitric acid.

In step (2), the inert material is one of graphite, platinum, titanium, silver and stainless steel.

In the cathode electrolyte of step (2), the concentration of polyvinyl pyrrolidone is 0.5g-5g/L, preferably 2g-4g/L, more preferably 2.5g/L, the palladium salt is one or more of palladium chloride, sodium tetrachloropalladate, palladium acetate, palladium sulfate, palladium nitrate, the palladium salt concentration is 5-50mg/L, preferably 20-30mg/L, more preferably 25mg/L, the sodium sulfate concentration is 5-50g/L, preferably 10-20g/L, more preferably 14.2g/L. In the anolyte of step (2), the sodium sulfate concentration is 5-50g/L, preferably 10-30g/L, more preferably 14.2g/L.

The process parameters of the cathode deposition method are: the applied current density is 0.05-0.15 A/dm ² , preferably 0.06-0.10 A/dm ² , more preferably 0.075 A/dm ² , and the deposition time is 20-60 min, preferably 25-40 min, more preferably 30 min.

The present invention performs the desired electrolytic reduction by techniques known in the art. Generally, the raw material chlorinated aromatic compound or a mixture thereof is dissolved or partially dissolved in a solvent, a certain amount of supporting electrolyte is added, and then sufficient current is passed through the electrolytic cell until the desired degree of reduction is obtained. After the electrolytic reaction is completed, the reaction solution is further pH-adjusted and the product is recovered by conventional techniques, such as acid precipitation filtration or chemical extraction.

The reactions involved in the electrochemical reduction of high-concentration chlorinated aromatic compounds described in the present invention (taking chloropicolinic acid as an example):

(1) Neutralization reaction:

(2) Cathode reaction:

(3) Anode reaction:

2n OH-→1/2n O ₂ +2n e-

(4) Overall reaction:

The beneficial effects of the present invention are mainly reflected in: the method for hydrogenating and dechlorinating high-concentration chlorinated aromatic compounds provided by the present invention can simultaneously achieve high reactant concentration (200g/L), high current density (2-10A/ ^dm2 ), low electrolysis voltage (≤3V), high conversion rate (≥99%), high selectivity (≥98%), and low energy consumption per unit product produced by electrolysis (SEEC≤6kW hkg ^-1 ), which can not only greatly reduce the amount of catalyst palladium used and reduce electrolysis energy consumption, but also produce high value-added products in the process of treating chlorinated organic matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a scanning electron microscopic comparison diagram of the palladium-modified nickel foam cathode prepared in Example 1 and Comparative Example 1.

DETAILED DESCRIPTION

The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

The formula for calculating the energy consumption per unit product produced by electrolysis (SEEC) in the embodiment of the present invention is: SEEC = (I × t × U) / (1000 × △ C × V) (kW h kg ^-1 )

Where: I is the current (A), t is the time (h), U is the average electrolysis voltage (V), △C is the mass concentration of the target product (kg/L), and V is the volume of the electrolyte (L).

Example 1 Preparation of palladium modified nickel foam cathode (PdNPs/Ni)

Cut 2cm×2cm nickel foam as the electrode substrate, first clean the grease on the substrate surface with acetone, then etch the substrate surface oxide layer with nitric acid aqueous solution to obtain the treated electrode substrate. The above treated electrode substrate is used as the working electrode, graphite is used as the counter electrode, an aqueous solution containing 2.5g/L polyvinyl pyrrolidone, 25mg/L sodium tetrachloropalladate with a palladium concentration of 14.2g/L sodium sulfate is used as the cathode electrolyte, and an aqueous solution containing 14.2g/L sodium sulfate is used as the anode electrolyte. A current density of 0.075A/ ^dm2 is applied, and the deposition time is 30min.

Example 2 Electrochemical hydrogenation dechlorination of 3,6-dichloropicolinic acid (3,6-D) at a concentration of 0.1 mol/L

In a membrane electrolyzer separated by an ion exchange membrane, palladium-modified nickel foam is used as the cathode (modification method is in accordance with Example 1), stainless steel is used as the anode, and the distance between the cathode and the cathode is 5 cm. 30 mL 1.0 mol/L NaOH + 19.2 g/L 3,6-D is used as the cathode liquid; 30 mL 1.0 mol/L NaOH is used as the anode liquid. During the electrolysis process, the temperature is controlled at 25°C, the current density is controlled at 2.5 A/dm ² , and the electrolysis voltage is 1.8 V to 2.4 V. After 5 hours of electrolysis, the cathode liquid is transferred to a beaker, sulfuric acid is added to adjust the pH to 4, and then the conversion rate of 3,6-D is 100%, the yield of picolinic acid is 95%, and the SEEC is 6.08 kW h kg ^-1 by high performance liquid chromatography.

The HPLC analysis conditions were as follows: a chromatographic column (150 mm length × 4.6 mm i.d., 5 μm particle size) was used as the separation column, the mobile phase volume ratio was a mixture of acetonitrile/methanol/water = 2/3/5 (containing 30 mmol/L phosphoric acid), the injection volume was 20 μL, the injection temperature was 30°C, the flow rate was 1 mL/min isocratic elution, the wavelength of the UV detector was 260 nm, and the external standard method was used to determine the standard curve for the quantitative calculation of reactants and products.

Example 3 Electrochemical hydrogenation dechlorination of 3,6-dichloropicolinic acid (3,6-D) at a concentration of 1 mol/L

In a diaphragm electrolyzer separated by an ion exchange membrane, palladium-modified nickel foam is used as cathode (modification method is in accordance with Example 1), stainless steel is used as anode, and the distance between the cathode and cathode is 5 cm. 30 mL 1.0 mol/L NaOH + 192 g/L 3,6-D is used as cathode liquid; 30 mL 1.0 mol/L NaOH is used as anode liquid. During the electrolysis process, the temperature is controlled at 25°C, and different current densities are applied in stages according to the electrolysis time of 0 h to 1 h, 1 h to 3 h, and 3 h to 8 h, which are 25 A/dm ² , 12.5 A/dm ² , and 2.5 A/dm ² , respectively, and the electrolysis voltages are 6.7 V to 11.2 V, 4.7 V to 5.5 V, and 2.9 V to 3.7 V, respectively. After 8 hours of electrolysis, the cathode solution was transferred to a beaker, sulfuric acid was added to adjust the pH to 4, and then HPLC analysis showed that the conversion of 3,6-D was 100%, the yield of picolinic acid was 95%, and the SEEC was 8.94 kW h kg ^-1 .

The HPLC analysis conditions were as follows: a chromatographic column (150 mm length × 4.6 mm i.d., 5 μm particle size) was used as the separation column, the mobile phase volume ratio was a mixture of acetonitrile/methanol/water = 2/3/5 (containing 30 mmol/L phosphoric acid), the injection volume was 20 μL, the injection temperature was 30°C, the flow rate was 1 mL/min isocratic elution, the wavelength of the UV detector was 260 nm, and the external standard method was used to determine the standard curve for the quantitative calculation of reactants and products.

Example 4 Electrochemical hydrogenation dechlorination of 4-amino-3,6-dichloropicolinic acid (4-N-3,6-D) at a concentration of 0.1 mol/L

In a diaphragm electrolyzer separated by an ion exchange membrane, palladium-modified nickel foam is used as the cathode (modification method is in accordance with Example 1), stainless steel is used as the anode, and the distance between the cathode and the cathode is 5 cm. 30 mL 1.0 mol/L NaOH + 20.7 g/L 4-N-3,6-D is used as the cathode liquid; 30 mL 1.0 mol/L NaOH is used as the anode liquid. During the electrolysis process, the temperature is controlled at 25°C, the current density is controlled at 2.5 A/dm ² , and the electrolysis voltage is 1.9 V to 2.4 V. After 8 hours of electrolysis, the cathode liquid is transferred to a beaker, sulfuric acid is added to adjust the pH to 4, and then the conversion rate of 4-N-3,6-D is 96%, the yield of 4-amino-picolinic acid is 95%, and the SEEC is 8.87 kW hkg ^-1 .

The HPLC analysis conditions were as follows: a chromatographic column (150 mm length × 4.6 mm i.d., 5 μm particle size) was used as the separation column, the mobile phase volume ratio was a mixture of acetonitrile/methanol/water = 2/3/5 (containing 30 mmol/L phosphoric acid), the injection volume was 20 μL, the injection temperature was 30°C, the flow rate was 1 mL/min isocratic elution, the wavelength of the UV detector was 260 nm, and the external standard method was used to determine the standard curve for the quantitative calculation of reactants and products.

Example 5 Electrochemical Hydrogenation Dechlorination of 2,4-Dichlorophenol (2,4-DCP) at a Concentration of 0.1 mol/L

In a diaphragm electrolyzer separated by an ion exchange membrane, palladium-modified nickel foam is used as the cathode (modification method is in accordance with Example 1), stainless steel is used as the anode, and the distance between the cathode and the cathode is 5 cm. 30 mL 1.0 mol/L NaOH + 16.3 g/L 2,4-DCP is used as the cathode liquid; 30 mL 1.0 mol/L NaOH is used as the anode liquid. During the electrolysis process, the temperature is controlled at 25°C, the current density is controlled at 2.5 A/dm ² , and the electrolysis voltage is 1.8 V to 2.4 V. After 8 hours of electrolysis, the cathode liquid is transferred to a beaker, sulfuric acid is added to adjust the pH to 4, and then the conversion rate of 2,4-DCP is 98%, the yield of phenol is 96%, and the SEEC is 12.68 kW hkg ^-1 by high performance liquid chromatography.

The HPLC analysis conditions were as follows: a chromatographic column (250 mm length × 4.6 mm i.d., 5 μm particle size) was used as the separation column, the mobile phase volume ratio was a mixture of methanol/water = 4/1 (containing 30 mmol/L phosphoric acid), the injection volume was 20 μL, the injection temperature was 20°C, the flow rate was 1 mL/min isocratic elution, the wavelength of the UV detector was 280 nm, and the external standard method was used to determine the standard curve for the quantitative calculation of reactants and products.

Embodiment 6 to Embodiment 20

Examples 6 to 20 were carried out according to the experimental parameters of Table 1, and the remaining operations were the same as those of Example 2. 3,6-Dichloropicolinic acid, 4-chlorophenoxyacetic acid, 4-chloroformic acid, 4-chlorophenol, and 2,4,6-trichlorophenol were represented by 3,6-D, 4-CPA, 4-CBA, 4-CP, and 2,4,6-TCP, respectively.

Table 1 Experimental conditions and results of Examples 6 to 20

Comparative Example 1 Conventional palladium-modified nickel foam cathode (Pd/Ni) catalyzes electrochemical hydrogenation and dechlorination of 3,6-dichloropicolinic acid (3,6-D) at a concentration of 0.1 mol/L (compared with Example 2)

The preparation of the Pd/Ni cathode was carried out according to Example 1, but without adding polyvinyl pyrrolidone during the preparation process.

In the diaphragm electrolyzer separated by ion exchange membrane, Pd/Ni is the cathode, stainless steel is the anode, and the distance between the cathode and the cathode is 5 cm. 30 mL 1.0 mol/L NaOH + 19.2 g/L 3,6-D is the cathode liquid; 30 mL 1.0 mol/L NaOH is the anode liquid. During the electrolysis process, the temperature is controlled at 25 ° C, the current density is controlled at 2.5 A/dm ² , and the electrolysis voltage is 1.8 V ~ 2.4 V. After 5 hours of electrolysis, the cathode liquid is transferred to a beaker, sulfuric acid is added to adjust the pH to 4, and then the conversion rate of 3,6-D is 95%, the yield of picolinic acid is 59%, and the SEEC is 10.86 kW h kg ^-1 by high performance liquid chromatography.

Comparative Example 1 shows that the electrochemical dechlorination of 3,6-D treated with the conventional Pd/Ni cathode cannot achieve the desired results (low yield, low current efficiency).

Comparative Example 2 Electrochemical hydrogenation dechlorination of 3,6-dichloropicolinic acid (3,6-D) at a low concentration of 0.001 mol/L (compared with Example 2 and Example 3)

In a membrane electrolyzer separated by an ion exchange membrane, palladium-modified nickel foam is used as the cathode (modification method is in accordance with Example 1), stainless steel is used as the anode, and the distance between the cathode and the cathode is 5 cm. 30 mL 1.0 mol/L NaOH + 192 mg/L 3,6-D is used as the cathode liquid; 30 mL 1.0 mol/L NaOH is used as the anode liquid. During the electrolysis process, the temperature is controlled at 25°C, the current density is controlled at 0.075 A/dm ² , and the electrolysis voltage is 1.9 V to 2.3 V. After 5 hours of electrolysis, the cathode liquid is transferred to a beaker, sulfuric acid is added to adjust the pH to 4, and then the conversion rate of 3,6-D is 100%, the yield of picolinic acid is 99%, and the SEEC is 11.15 kW hkg ^-1 by high performance liquid chromatography.

Comparative Example 2 shows that the electrochemical dechlorination of low-concentration 2,4-D cannot obtain ideal results (low current density, low current efficiency, and low space-time yield).

Claims (10)

1. A process for the hydrodechlorination of chlorinated aromatic compounds in high concentrations, said process comprising: adding a chlorinated aromatic compound shown in a formula (I) into an alkaline aqueous solution to obtain catholyte, taking the alkaline aqueous solution as anolyte, a palladium modified electrode as a cathode and stainless steel as an anode, carrying out an electrolytic reaction in an electrolytic tank separated by an ion exchange membrane, obtaining an electrolyte containing a dechlorinated compound shown in a formula (II) after the electrolytic reaction is finished, and separating and purifying the electrolyte to obtain the dechlorinated compound shown in the formula (II), wherein the chlorinated aromatic compound shown in the formula (I) is characterized in that: the palladium modified electrode is prepared by adopting a cathode deposition method;

XRCln XRHn

（Ⅰ） （Ⅱ）

in the formula (I), R is a single benzene ring or a single pyridine ring; x is hydroxyl, carboxyl or methoxy acetate, and n is one of positive integers between 1~5; r, X and n in formula (II) are the same as formula (I).

2. The process for the hydrodechlorination of chlorinated aromatic compounds in high concentrations according to claim 1, characterized in that: the palladium modified electrode is prepared by the following specific method:

(1) Taking a conductive material as an electrode matrix, firstly cleaning grease on the surface of the matrix by using an organic solvent, and then etching an oxide layer on the surface of the matrix by using an acidic aqueous solution to obtain a treated electrode matrix;

(2) And (2) taking the treated electrode matrix obtained in the step (1) as a cathode, taking an inert material as an anode, taking an aqueous solution containing polyvinylpyrrolidone, sodium sulfate and palladium salt as a catholyte, taking an aqueous solution of sodium sulfate as an anolyte, and preparing the palladium modified electrode by adopting a cathodic deposition method.

3. The process for the hydrodechlorination of chlorinated aromatic compounds in high concentrations according to claim 2, characterized in that: in the step (1), the electrode substrate is a metal selected from nickel, stainless steel, titanium and silver or carbon selected from graphite, carbon fiber, carbon felt and glassy carbon, the organic solvent is one or more of acetone, ethanol, methanol and ether, and the acidic aqueous solution is one or more of aqueous solutions of sulfuric acid, hydrochloric acid and nitric acid.

4. The process for the hydrodechlorination of chlorinated aromatic compounds in high concentrations according to claim 2, characterized in that: in the electrolyte in the step (2), the concentration of polyvinylpyrrolidone is 0.5 g-5 g/L, the palladium salt is one or more of palladium chloride, sodium tetrachloropalladate, palladium acetate, palladium sulfate and palladium nitrate, the concentration of palladium is 5-50mg/L, and the concentration of sodium sulfate is 5-50g/L.

5. The process for the hydrodechlorination of chlorinated aromatic compounds in high concentrations according to claim 2, characterized in that: the cathode deposition method comprises the following process parameters: the applied current density is 0.05 to 0.15A/dm ² The deposition time is 20 to 60min.

6. The process for the hydrodechlorination of chlorinated aromatic compounds in high concentrations according to claim 2, characterized in that: the palladium loading capacity of the palladium modified electrode is 0.5 to 5g/m ² 。

7. The process for the hydrodechlorination of chlorinated aromatic compounds in high concentrations according to claim 1, characterized in that: the concentration of the chlorinated aromatic compound shown in the formula (I) in the catholyte is 5-300g/L.

8. The process for the hydrodechlorination of chlorinated aromatic compounds in high concentrations according to claim 1, characterized in that: the chlorinated aromatic compound shown in the formula (I) is one or more of chloropicolinic acid, chlorophenol, chlorobenzoic acid and chlorophenoxyacetic acid.

9. The process for the hydrodechlorination of chlorinated aromatic compounds in high concentrations according to claim 1, characterized in that: the conditions of the electrolytic reaction are as follows: the current density is 1 to 20A/dm ² The temperature is 0 to 100 ℃.

10. The process for the hydrodechlorination of chlorinated aromatic compounds in high concentrations according to claim 1, characterized in that: the alkaline aqueous solution is prepared by mixing water and supporting electrolyte; the concentration of the supporting electrolyte in the electrolyte is 0.1 to 2.0mol/L.

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