Ectopic remediation method for groundwater polluted by chlorinated nitrobenzenes

Abstract

The invention discloses an ex-situ remediation method suitable for chloronitrobenzene type polluted ground water. The method comprises the following steps: filtering polluted water to remove mechanical impurities, and then, adding reducing iron powder and stirring for reaction, wherein additive amount of the reducing iron powder is 30-40% of COD (Chemical Oxygen Demand) content, and reducing chloronitrobenzene with zero-valent iron to generate ferrous ions Fe<2+> and phenylamine; 3-5 days later after reduction reaction, adding FeSO4.7H2O of which the additive amount is 30% of COD content, and stirring to realize miscibility; gradually adding H2O2 with mass concentration of 30% into a reaction solution to realize oxidizing reaction according to the additive amount of 3-5 times of COD content, and oxidizing the ferrous ions into ferric ions; after the oxidizing reaction, adding Ca(OH)2 according to the amount of 0.1-0.2% of mass of polluted water solution, and regulating pH to 6-9; and finally, removing sediment by virtue of filtering and separating. The ex-situ remediation method uses a zero-valent iron reduction treatment method and a Fenton's reagent oxidizing treatment method in combination, has an obvious remediation effect on the chloronitrobenzene type polluted ground water, and has high pollutant removal rate.

Description

technical field

[0001] The invention belongs to the technical field of restoration and treatment of polluted groundwater, and relates to an ex-situ restoration method suitable for groundwater polluted by chlorinated nitrobenzenes. Background technique

[0002] Chloronitrotoluene compounds are widely used in national defense, printing and dyeing, plastics, pesticides and pharmaceutical industries. The annual discharge of chloronitrotoluene into the environment in the world exceeds 100 tons, causing great harm to the ecological environment. Many such The compound is listed as a priority pollutant by the U.S. Environmental Protection Agency, and it is of practical significance to strictly control the content of chloronitrotoluene in water. The benzene ring of chloronitrotoluene compounds has a dense electron cloud, and it is difficult to provide electrons. It is difficult to remove chloronitrobenzene compounds by oxidation. Moreover, the oxidation of chloronitrobenzene may pro...

Examples

Embodiment 1

[0018] The present invention is suitable for a small-scale test of an ex-situ remediation method for groundwater polluted by chlorinated nitrobenzenes

[0019] 1. Experimental method

[0020] 1. Experimental materials

[0021] The groundwater polluted by chloronitrotoluene compounds and petroleum hydrocarbons was collected from a site in Shengsi. The concentrations of 4-chloro-2-nitrotoluene and total petroleum hydrocarbons in sewage were 21 and 7.3 mg·L, respectively -1 , COD content is 3620mg·L -1 .

[0022] The reduced iron powder (Fe 0 ), hydrogen peroxide (H 2 o 2 ,30%), ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) and calcium hydroxide (Ca(OH) 2 ) are analytically pure.

[0023] 2. Experimental operation

[0024] The sewage was filtered with a 45nm microporous membrane before the experiment, and the initial pH was determined to be 3. Add 1g (30% of COD content) of Fe to 1L reaction solution 0 , after 5 days of reaction, add 1g FeSO 4 ·7H 2 O (30% of COD c...

Embodiment 2

[0034] 1. Experimental materials

[0035] Chloronitrotoluene compounds and petroleum hydrocarbons polluted groundwater from a site in Shanghai. The concentrations of 4-chloro-2-methylphenol and total petroleum hydrocarbons in sewage were 34 and 12 mg·L, respectively -1 , COD content is 3950mg·L -1 .

[0036] The reduced iron powder (Fe 0 ), hydrogen peroxide (H 2 o 2 ,30%), ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) and calcium hydroxide (Ca(OH) 2 ) are analytically pure.

[0037] 2. Experimental operation

[0038] The sewage was filtered with a 45nm microporous membrane before the experiment, and the initial pH was determined to be 3.2. Add 1.5g (40% of COD content) of Fe to 1L reaction solution 0 , after 3 days of reaction, add 1.2g FeSO 4 ·7H 2 O (30% of COD content), stir until miscible, and prepare 12g (10.5mL, 30%; 3 times of COD content) H 2 o 2 And gradually added to the reaction solution, the reaction time is more than 1 day, and the pH value of the ...

Embodiment 3

[0048] 1. Experimental materials

[0049] Chloronitrotoluene compounds and petroleum hydrocarbons polluted groundwater from a site in Shanghai. The concentrations of 5-chloro-2nitrobenzyl alcohol and total petroleum hydrocarbons in sewage were 26 and 10 mg·L, respectively -1 , COD content is 3790mg·L -1 .

[0050] The reduced iron powder (Fe 0 ), hydrogen peroxide (H 2 o 2 ,30%), ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) and calcium hydroxide (Ca(OH) 2 ) are analytically pure.

[0051] 2. Experimental operation

[0052] The sewage was filtered with a 45nm microporous membrane before the experiment, and the initial pH was determined to be 3.5. Add 1.3g (35% of COD content) of Fe to 1L reaction solution 0 , after 4 days of reaction, add 1.1g (30% of COD content) FeSO 4 ·7H 2 O, stir until miscible, configure 8g (7mL, 30%; 2 times the content of COD) H 2 o 2 and gradually added to the reaction solution, the reaction time is about 1 day, and the pH value of the ...

technical field

[0001] The invention belongs to the technical field of restoration and treatment of polluted groundwater, and relates to an ex-situ restoration method suitable for groundwater polluted by chlorinated nitrobenzenes. Background technique

[0002] Chloronitrotoluene compounds are widely used in national defense, printing and dyeing, plastics, pesticides and pharmaceutical industries. The annual discharge of chloronitrotoluene into the environment in the world exceeds 100 tons, causing great harm to the ecological environment. Many such The compound is listed as a priority pollutant by the U.S. Environmental Protection Agency, and it is of practical significance to strictly control the content of chloronitrotoluene in water. The benzene ring of chloronitrotoluene compounds has a dense electron cloud, and it is difficult to provide electrons. It is difficult to remove chloronitrobenzene compounds by oxidation. Moreover, the oxidation of chloronitrobenzene may pro...

Examples

Embodiment 1

[0018] The present invention is suitable for a small-scale test of an ex-situ remediation method for groundwater polluted by chlorinated nitrobenzenes

[0019] 1. Experimental method

[0020] 1. Experimental materials

[0021] The groundwater polluted by chloronitrotoluene compounds and petroleum hydrocarbons was collected from a site in Shengsi. The concentrations of 4-chloro-2-nitrotoluene and total petroleum hydrocarbons in sewage were 21 and 7.3 mg·L, respectively -1 , COD content is 3620mg·L -1 .

[0022] The reduced iron powder (Fe 0 ), hydrogen peroxide (H 2 o 2 ,30%), ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) and calcium hydroxide (Ca(OH) 2 ) are analytically pure.

[0023] 2. Experimental operation

[0024] The sewage was filtered with a 45nm microporous membrane before the experiment, and the initial pH was determined to be 3. Add 1g (30% of COD content) of Fe to 1L reaction solution 0 , after 5 days of reaction, add 1g FeSO 4 ·7H 2 O (30% of COD c...

Embodiment 2

[0034] 1. Experimental materials

[0035] Chloronitrotoluene compounds and petroleum hydrocarbons polluted groundwater from a site in Shanghai. The concentrations of 4-chloro-2-methylphenol and total petroleum hydrocarbons in sewage were 34 and 12 mg·L, respectively -1 , COD content is 3950mg·L -1 .

[0036] The reduced iron powder (Fe 0 ), hydrogen peroxide (H 2 o 2 ,30%), ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) and calcium hydroxide (Ca(OH) 2 ) are analytically pure.

[0037] 2. Experimental operation

[0038] The sewage was filtered with a 45nm microporous membrane before the experiment, and the initial pH was determined to be 3.2. Add 1.5g (40% of COD content) of Fe to 1L reaction solution 0 , after 3 days of reaction, add 1.2g FeSO 4 ·7H 2 O (30% of COD content), stir until miscible, and prepare 12g (10.5mL, 30%; 3 times of COD content) H 2 o 2 And gradually added to the reaction solution, the reaction time is more than 1 day, and the pH value of the ...

Embodiment 3

[0048] 1. Experimental materials

[0049] Chloronitrotoluene compounds and petroleum hydrocarbons polluted groundwater from a site in Shanghai. The concentrations of 5-chloro-2nitrobenzyl alcohol and total petroleum hydrocarbons in sewage were 26 and 10 mg·L, respectively -1 , COD content is 3790mg·L -1 .

[0050] The reduced iron powder (Fe 0 ), hydrogen peroxide (H 2 o 2 ,30%), ferrous sulfate heptahydrate (FeSO 4 ·7H 2 O) and calcium hydroxide (Ca(OH) 2 ) are analytically pure.

[0051] 2. Experimental operation

[0052] The sewage was filtered with a 45nm microporous membrane before the experiment, and the initial pH was determined to be 3.5. Add 1.3g (35% of COD content) of Fe to 1L reaction solution 0 , after 4 days of reaction, add 1.1g (30% of COD content) FeSO 4 ·7H 2 O, stir until miscible, configure 8g (7mL, 30%; 2 times the content of COD) H 2 o 2 and gradually added to the reaction solution, the reaction time is about 1 day, and the pH value of the ...