# US 11,897,797 B2 · Method for remediating groundwater organic contamination by in-situ reaction zone

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- Number: US 11,897,797 B2
- Document ID: US11897797B2
- Status: Granted
- Kind: B2
- Application number: 18/198,994
- Filed: 2023-05-18
- Published: 2023-11-23
- Granted: 2024-02-13
- Earliest claimed: 2022-05-19
- Assignees: Chengdu University of Technology
- Applicants: Chengdu University of Technology
- Inventors: Shengyan Pu; Hui Ma; Dong Yu; Dongyuan Luo; Junyan Du; Xinxin Ni; Zhu Miao; Yu Wang
- Web page: https://patentgrep.com/patent/US11897797B2

## CPC

- C02F 1/705: {Reduction by metals}
- B09C 1/002: {involving in-situ ground water treatment}
- B09C 1/08: chemically
- C02F 1/722: {Oxidation by peroxides}
- C02F 2101/345: {Phenols}
- C02F 2101/36: containing halogen
- C02F 2101/363: {PCB's; PCP's}
- C02F 2103/06: Contaminated groundwater or leachate
- C02F 2209/06: pH
- C02F 2209/19: SO4-S
- C02F 2209/29: Chlorine compounds
- C02F 2209/40: Liquid flow rate
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- B09C: RECLAMATION OF CONTAMINATED SOIL (gatherers for removing stone or the like from the soil A01B43/00; sterilising soil by steam A01G11/00; removing undesirable matter, e.g. rubbish, from the land E01H15/00)

## Abstract

The present disclosure belongs to the field of environmental protection and relates to a method for remediating groundwater chlorophenols organic contamination. The method includes determining a location of a contamination source; setting up an injection well based on the location of the contamination source; and injecting a remediation reagent into groundwater in a to-be-remediated region through the injection well so as to degrade chlorophenols organic contamination in the groundwater in the to-be-remediated region.

## Claims

### Claim 1

A method for remediating groundwater chlorophenols organic contamination, comprising the following steps of:
step S1. determining a location of a contamination source;
step S2. setting up an injection well in upstream in a flowing direction of the groundwater of the contamination source; and
step S3. degrading chlorophenols organic contamination in groundwater in the to-be-remediated region by injecting a remediation reagent into groundwater in a to-be-remediated region through the injection well;
wherein,
the step S3 comprises: detecting a flow rate of the groundwater in the to-be-remediated region,
when the flow rate is greater than 4 m/d, the remediation reagent comprises sulfidated nanoscale zero-valent iron and hydrogen peroxide, wherein an iron-sulfur ratio in the sulfidated nanoscale zero-valent iron is 15; and
when the flow rate is smaller than or equal to 4 m/d, the remediation reagent comprises sulfidated nanoscale zero-valent iron modified by sodium carboxymethylcellulose and hydrogen peroxide, wherein the sodium carboxymethylcellulose in the sulfidated nanoscale zero-valent iron modified by sodium carboxymethylcellulose is used at a concentration of 1.0 g·L−1.

### Claim 2 (depends on 1)

The method of claim 1, wherein the sulfidated nanoscale zero-valent iron is prepared by the following steps:
adding absolute ethyl alcohol into a prepared FeSO4 solution for stirring, dropwise adding a NaOH solution with dissolved NaBH4, and then reacting to obtain nanoscale zero-valent iron; and
adding the obtained nanoscale zero-valent iron into a prepared Na2S solution, obtaining a sulfidated nanoscale zero-valent iron suspension liquid through ultrasonic, and thereby preparing the sulfidated nanoscale zero-valent iron.

### Claim 3 (depends on 1)

The method of claim 1, wherein the sulfidated nanoscale zero-valent iron modified by sodium carboxymethylcellulose is prepared by the following steps:
adding the sulfidated nanoscale zero-valent iron into a debubbled sodium carboxymethylcellulose solution, performing ultrasonic dispersion, then freezing and shaking well to obtain a sulfidated nanoscale zero-valent iron suspension liquid modified by sodium carboxymethylcellulose, and thereby obtaining the sulfidated nanoscale zero-valent iron modified by sodium carboxymethylcellulose after magnetic separation.

### Claim 4 (depends on 1)

The method of claim 1, wherein when the flow rate is greater than 4 m/d, an amount of the added sulfidated nanoscale zero-valent iron is 0.5 g per liter of groundwater, a concentration of H2O2 is 3 mM, and pH is 4.

### Claim 5 (depends on 1)

The method of claim 1, wherein when the flow rate is smaller than or equal to 4 m/d, an amount of the added sulfidated nanoscale zero-valent iron modified by sodium carboxymethylcellulose is 0.6 g per liter of groundwater, a concentration of H2O2 is 5 mM, and pH is 4.

### Claim 6 (depends on 1)

The method of claim 1, wherein before injecting the remediation reagent, a concentration of SO42− in the groundwater in the to-be-remediated is adjusted to a range of 1 mM to 100 mM, and a concentration of is adjusted to a range of 1 mM to 10 mM.

### Claim 7 (depends on 1)

The method of claim 1, wherein, a plurality of monitoring wells are arranged in a to-be-remediated region, when the remediation reagent is injected at interval time, a next injection node of the remediation reagent is determined through change conditions of one or more monitored parameters of a pollutant concentration, a total iron concentration distribution and a pH value in the groundwater monitored in real time by each monitoring well, wherein the injection node is at least at a moment when any one or more monitored parameters have an inflection point in a range curve in data obtained from all the monitoring wells.

### Claim 8 (depends on 7)

The method of claim 7, wherein at least one processing unit capable of receiving real-time monitored data of each monitoring well is configured to analyze the injection node of the remediation reagent, wherein, a monitoring frequency that the processing unit obtains the real-time monitored data of each monitoring well is adjusted at least in a periodic fluctuation mode based on the injection node of the remediation reagent, and a peak value of the monitoring frequency can be set higher than a peak value of a previous fluctuation period.

### Claim 9 (depends on 7)

The method of claim 7, wherein S-nZVI or CMC-S-nZVI in the remediation reagent can be recycled repeatedly under a condition of controlling a degradation rate of a pollutant to be at least greater than 70%.

### Claim 10 (depends on 2)

The method of claim 2, wherein before injecting the remediation reagent, a concentration of SO42− in the groundwater in the to-be-remediated is adjusted to a range of 1 mM to 100 mM, and a concentration of Cl− is adjusted to a range of 1 mM to 10 mM.

### Claim 11 (depends on 3)

The method of claim 3, wherein before injecting the remediation reagent, a concentration of SO42− in the groundwater in the to-be-remediated is adjusted to a range of 1 mM to 100 mM, and a concentration of Cl−1 is adjusted to a range of 1 mM to 10 mM.

### Claim 12 (depends on 4)

The method of claim 4, wherein before injecting the remediation reagent, a concentration of SO42− in the groundwater in the to-be-remediated is adjusted to a range of 1 mM to 100 mM, and a concentration of Cl− is adjusted to a range of 1 mM to 10 mM.

### Claim 13 (depends on 5)

The method of claim 5, wherein before injecting the remediation reagent, a concentration of SO42− in the groundwater in the to-be-remediated is adjusted to a range of 1 mM to 100 mM, and a concentration of Cl− is adjusted to a range of 1 mM to 10 mM.

### Claim 14 (depends on 2)

The method of claim 2, wherein before injecting the remediation reagent, a concentration of HCO3− in the groundwater is less than 10 mM, and a concentration of NO3− is less than 10 mM.

### Claim 15 (depends on 3)

The method of claim 3, wherein before injecting the remediation reagent, a concentration of HCO3− in the groundwater is less than 10 mM, and a concentration of NO3− is less than 10 mM.

### Claim 16 (depends on 4)

The method of claim 4, wherein before injecting the remediation reagent, a concentration of HCO3− in the groundwater is less than 10 mM, and a concentration of NO3− is less than 10 mM.

### Claim 17 (depends on 5)

The method of claim 5, wherein before injecting the remediation reagent, a concentration of HCO3− in the groundwater is less than 10 mM, and a concentration of NO3− is less than 10 mM.