CN111453832A - A method, medium material and application for remediating PAEs pollution in groundwater - Google Patents

Abstract

The invention discloses a medium material for repairing PAEs pollution in groundwater and its application in repairing PAEs pollution in groundwater. The medium material includes persulfate and ZVI as a persulfate activator, which cooperate to form PAEs oxidation system. The invention also discloses a method for repairing PAEs pollution in groundwater, which adopts ZVI and persulfate to be used together, both are added to the groundwater to be repaired, and the persulfate is activated and converted into sulfate free radicals by ZVI, Highly oxidative degradation of PAEs by free radicals. The invention adopts the ZVI-persulfate oxidation system to repair the PAEs pollution in the groundwater, which has little disturbance to the underground aquifer, can stably exist in the groundwater environment and can effectively degrade the PAEs in the groundwater.

Description

A method, medium material and application for remediating PAEs pollution in groundwater

technical field

The invention relates to the field of underground pollution remediation, in particular to a method, medium material and application for remediating PAEs pollution in groundwater.

Background technique

Phthalates (pathalate acid esters, PAEs) are widely used as additives in various industrial products and daily products, among which PAEs with smaller molecular weight are mainly used in cosmetics, pesticides, adhesives and other products while PAEs containing longer alkyl chains are added to plastic products and rubber products as plasticizers (Yang Zhihao et al., 2018), the most common and widely used are phthalate diesters (DEHP), phthalate Dibutyl formate (DBP) and dimethyl phthalate (DMP) (He et. al, 2019). When acute or chronic exposure occurs through ingestion or skin contact, PAEs may have deleterious effects on human health (Felipe et.al, 2003). In recent years, PAEs have been detected in groundwater (Deng et al., 2011).

At present, the most widely used technology for the removal of PAEs pollution in groundwater is advanced oxidation, which mainly includes photocatalytic oxidation (Lin et.al, 2011), ozone oxidation (Wen et.al, 2011), ultraviolet photolysis (Wang et.al, 2011) , 2014) and Fenton oxidation (Tay et.al, 2011). These technologies all have certain limitations. UV photolysis and photocatalytic photolysis can interfere with the protist community of underground aquifers while removing pollutants; the degradation rate of hydrogen peroxide itself is too fast to fully react with PAEs (Watts et.al, 2006); ozone dissolution is too low to exist well in groundwater environments (Scott et.al, 2006).

The references cited above are as follows:

1. Yang Zhihao, He Mingjing, Yang Ting. The pollution distribution characteristics and source analysis of phthalates in urban soil in Chongqing [J]. Environmental Science, 2018,39(07):3358-3364.

2. Alatriste-Mondragon, F.; Iranpour, R.; Ahring, B.K. Toxicity of di-(2-ethylhexyl)phthalate on the anaerobic digestion of wastewater sludge. WaterRes. 2003, 37, 1260-1269, doi: 10.1016/s0043 -1354(02)00387-1.

3. Deng Chen, Luo Dinggui, Chen Diyun. Simulation study on the migration of phthalates in the vadose zone soil layer [J]. China Environmental Science, 2011,31(12):2018-2022.

4. He,Y.;Wang,Q.;He,W.;Xu,F.The occurrence,composition and partitioning of phthalate esters(PAEs) in the water-suspended particulatematter(SPM)system of Lake Chaohu,China.Sci. Total Environ.2019,661,285-293,doi:10.1016/j.scitotenv.2019.01.161

5. Lin, Y.T.; Liang, C.; Chen, J.H. Feasibility study of ultravioletactivated persulfate oxidation of phenol.Chemosphere 2011, 82, 1168-1172, doi: 10.1016/j.chemosphere.2010.12.027.

6. G.Wen,J.Ma,Z.Q.Liu,L.Zhao,Ozonation kinetics for the degradation of phthalate esters in water and the reduction of toxicity in the process of O3/H2O2,J.Hazard.Mater.,195(2011) :371–377.

7. L. Wang, G. Y. Fu, B. Zhao, Z. Zhang, X. Guo, H. Zhang, Degradation of di-n-butyl phthalate in aqueous solution by the O3/UV process, Desal. Wat Treat., 52 (2014) 824–833.

8. K.S.Tay, N.A.Rahman, M.R.B.Abas, Fenton degradation of dialkylphthalates: products and mechanism, Environ.Chem.Lett., 9(2011) 539–546.

9. R.J.Watts, A.L.Teel, Treatment of contaminated soils and groundwater using ISCO, Pract.Period.Hazard.Toxic Radioact.Waste Manage.t, 10(2006) 2–9.

10. G.H. Scott, E.P. Bruce, Engineering Issue Paper: in-situ chemical oxidation. EPA 600-R06-072, U.S. EPA, Office of Research and Development, Cincinnati, 2006.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a medium material for repairing PAEs pollution in groundwater, so that it can effectively degrade PAEs in groundwater.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

A medium material for repairing PAEs pollution in groundwater includes persulfate and ZVI (zero valent iron, zero valent iron) as a persulfate activator, and the two cooperate to form a PAEs oxidation system.

As a further improvement of the present invention, the persulfate is sodium persulfate or potassium persulfate.

Further, the concentration ratio of the ZVI to the persulfate is 6:1 to 7:1.

Further, the concentration ratio of the persulfate to PAEs is 10:1-12:1.

The invention also provides the application of the above-mentioned medium material in repairing the PAEs pollution in groundwater.

The invention also provides a method for repairing PAEs pollution in groundwater. ZVI and persulfate are used together, both of which are added to the groundwater to be repaired, the persulfate is activated and converted into sulfate free radicals by ZVI, and the free highly oxidative degradation of PAEs.

Further, the pH value of the groundwater to be repaired is 6-8.

Further, the persulfate is sodium persulfate or potassium persulfate.

Further, during use, the use concentration of the persulfate is 10-12 times the concentration of PAEs, and the use concentration of the ZVI is 6-7 times the concentration of the persulfate.

After adopting the above-mentioned technical scheme, the present invention has at least the following advantages:

The ZVI-persulfate oxidation system proposed in the present invention can be used for repairing PAEs pollution in groundwater, and the persulfate conversion rate is appropriate, and can be used as a groundwater PRB (permeable reactive barrier, permeable reactive wall) medium, which solves the problem that PAEs are difficult in the groundwater environment. degradation problem.

Description of drawings

The above is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Figure 1 shows the degradation curves of PAEs with different carbon chain lengths under different temperature conditions (a: 15°C, b: 20°C, c: 25°C, d: 30°C);

Figure 2 is a graph of changes in iron ion concentration and pH during DBP degradation under different temperature conditions (a: 15°C, b: 20°C, c: 25°C, d: 30°C);

Figure 3 is a diagram of persulfate-sulfate conversion under different temperature conditions (a: 15°C, b: 20°C, c: 25°C, d: 30°C).

Detailed ways

This embodiment provides a medium material for repairing PAEs pollution in groundwater, including persulfate and ZVI (zero valent iron) as a persulfate activator, and the two cooperate to form a PAEs oxidation system.

As we all know, sodium persulfate itself has stable properties and strong oxidizing properties. However, sodium persulfate needs to be converted into sulfate free radicals to take advantage of the high oxidative properties of free radicals to degrade organic matter. Existing activation methods include heat, UV light, microwaves and treatment with transition metal ions (Antoniou et.al, 2010; Fang et.al, 2012). Iron in transition metals has two valence states of +2 and +3 at the same time, which can be used for the activation of persulfate, and it is mostly found in various minerals in underground aquifers, and will not cause too much impact on the aquifer. ZVI (zero valent iron) has the advantages of high efficiency, high cost performance, non-toxicity (Li et.al, 2014) and slow release of Fe ²⁺ , and can be used for the activation of persulfate. The reaction equation is as follows:

The present invention has verified the effectiveness of the ZVI-persulfate oxidation system for degrading PAEs through the method of indoor batch experiments, and the specific experimental scheme is shown in Table 1:

Table 1 Batch experimental design table

离子浓度。During the experiment, the residual concentration of PAEs, Fe ²⁺ and

ion concentration.

As shown in Figure 1, in this system, the degradation rates of DEHP, DBP and DMP at 15°C are about 32%, 47% and 5%, respectively; the order of the degradation rates at 15-20°C is: DBP >DEHP>DMP; DBP had the highest degradation rate under all temperature conditions in the experiment. The degradation rate of DEHP is greatly affected by temperature. However, DEHP, DBP and DMP could be degraded by the ZVI-persulfate oxidation system under all temperature conditions.

And throughout the experiment, Fe ²⁺ was always present (see Figure 2). In this system, the formation of Fe ²⁺ and the accompanying activation rate of persulfate (see Figure 3) are appropriate.

The ZVI-persulfate oxidation system proposed by the present invention has little disturbance to the underground aquifer, exists stably in the groundwater environment, and has an appropriate persulfate conversion rate, and can be used as a groundwater PRB (permeable reactive barrier, permeable reactive wall) medium, which solves the problem. In the past, the oxidation technology caused great disturbance to the environment and was not suitable for the groundwater environment.

The references cited above are as follows:

11. M.G.Antoniou, A.A.D.La Cruz, D.D.Dionysiou, Degradation of microcystin-LR using sulfate radicals generated through photolysis, thermolysis and e-transfer mechanisms, Appl.Catal.B., 96(2010) 290–298.

12. J. Fang, C. Shang, Bromate formation from bromide oxidation by the UV/persulfate process, Environ. Sci. Technol., 46(2012): 8976–8983.

13. H.Li,J.Wan,Y.Ma,Y.Wang,M.Huang,Influence of particle size of zero-valent iron and dissolved silica on the reactivity of activated persulfatefor degradation of acid orange 7,Chem.Eng. J., 237 (2014) 487–496.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Those skilled in the art make some simple modifications, equivalent changes or modifications by using the technical contents disclosed above, all of which fall within the scope of the present invention. within the scope of protection of the invention.

Claims (10)

1. A medium material for repairing PAEs pollution in groundwater, characterized in that it comprises persulfate and ZVI as a persulfate activator, and the two cooperate to form a PAEs oxidation system. 2 . The medium material according to claim 1 , wherein the persulfate is sodium persulfate or potassium persulfate. 3 . 3 . The medium material according to claim 2 , wherein the concentration ratio of the ZVI to the persulfate is 6:1 to 7:1. 4 . 4 . The dielectric material according to claim 3 , wherein the concentration ratio of the persulfate to the PAEs is 10:1 to 12:1. 5 . 5. The application of the medium material according to any one of claims 1 to 4 in repairing PAEs pollution in groundwater. 6. A method for repairing PAEs pollution in groundwater, characterized in that, ZVI and persulfate are used together, both are added to the groundwater to be repaired, and the persulfate is activated and converted into sulfate free radicals by ZVI, and the Highly oxidative degradation of PAEs by free radicals. 7 . The method for repairing PAEs pollution in groundwater according to claim 6 , wherein the pH value of the groundwater to be repaired is 6-8. 8 . 8 . The method for repairing PAEs pollution in groundwater according to claim 7 , wherein the pH value of the groundwater to be repaired is 7. 9 . 9 . The method for repairing PAEs pollution in groundwater according to claim 6 , wherein the persulfate is sodium persulfate or potassium persulfate. 10 . 10 . The method for remediating PAEs pollution in groundwater according to claim 9 , wherein, when used, the concentration of the ZVI is 6 to 7 times that of the persulfate, and the concentration of the persulfate is 10 to 10 . 12 times the concentration of PAEs.

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