Method for removing heavy metals in soil or plants by using triethylamine hydrogen sulfate ionic liquid

A technology of triethylamine hydrogen sulfate and ionic liquid, which is applied in the restoration of polluted soil and other directions, can solve the problems of low moisture tolerance, low thermal stability, high price, etc., and achieves cost control, simple process, and easy operation conditions. control effect

Active Publication Date: 2020-04-17

清华苏州环境创新研究院 +1

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AI-Extracted Technical Summary

Problems solved by technology

[0004] At the same time, current ionic liquids still have some disadvantages, suc...

Abstract

The invention relates to a method for removing heavy metals in soil or plants by using a triethylamine hydrogen sulfate ionic liquid ([TEA][HSO4]). The method comprises the following steps: slowly adding a concentrated sulfuric acid solution into a triethylamine solution at a constant low temperature; after mixing is finished, standing at the same temperature; removing residual moisture and amineby using a rotary evaporator to obtain a triethylamine hydrogen sulfate ionic liquid; and mixing heavy metal contaminated soil or plants and the obtained ionic liquid to remove heavy metals. Comparedwith the method in the prior art, the method of the invention is simple and clear in process, controllable in operation condition, excellent in cost benefit, remarkable in heavy metal removal effect and free of negative influence on a soil structure and an ecological system, wherein the ionic liquid has excellent recyclability.

Application Domain

Contaminated soil reclamation

Technology Topic

Contaminated soilsEnvironmental chemistry +8

Examples

Experimental program(4)

Example Embodiment

[0020] Example 1

[0021] A method of using triethylamine hydrogen sulfate ionic liquid ([TEA][HSO4]) to remove heavy metals in soil, the steps are as follows:

[0022] (1) Preparation of ionic liquid

[0023] In a constant low temperature (4°C) ice water bath, 150 mL of 5M concentrated sulfuric acid solution (95.0-98.0 wt.%) was slowly added to 104.5 mL of triethylamine solution (99 wt.%). After the mixing is completed, continue to stand for 30 minutes at the same temperature;

[0024] (2) Rotary evaporation

[0025] Put the clear solution obtained in step (1) into a rotary evaporator until the water and excess amine are completely sublimated and escaped;

[0026] In particular, after the mixing reaction is complete, the solution is placed in a rotary evaporator at a temperature of 80° C., a rotation speed of 200 r/min, and a time of 10 hours, until the excess water and amine are evaporated and escaped.

[0027] (3)Medium temperature solid-liquid reaction

[0028] After washing the soil contaminated by heavy metals, grind to fine particles (below 30 mesh), and dry at 60°C for use. The dried and sieved soil was mixed with triethylamine hydrogen sulfate ionic liquid in a ratio of 1:30, the temperature was 90°C, and the reaction time was 8 hours. After the reaction system is cooled to normal temperature, the soil sample is washed out with 97% ethanol solution and transferred to a 50mL centrifuge tube; centrifuge at 15°C, 2000xg rotation speed for 50 minutes to collect the ethanol centrifuge solution. The centrifugation process was repeated 3 times. After centrifugation, the soil was transferred to a cellulose sleeve, the ethanol centrifugal liquid was placed in a round-bottomed flask, and a Sox-type extraction device was used at 150°C for 20 hours to remove the ionic liquid residue in the soil sample.

[0029] The removal rate of soil heavy metal As was 82.1%, the removal rate of Cd was 96.6%, the removal rate of Fe was 54.9%, the removal rate of Mn was 94.8%, and the removal rate of Zn was 64.0%.

Example Embodiment

[0030] Example 2

[0031] A method of using triethylamine hydrogen sulfate ionic liquid ([TEA][HSO4]) to remove heavy metals in soil, the steps are as follows:

[0032] (1) Preparation of ionic liquid

[0033] In a constant low temperature (4°C) ice water bath, 150 mL of 5M concentrated sulfuric acid solution (95.0-98.0 wt.%) was slowly added to 104.5 mL of triethylamine solution (99 wt.%). After the mixing is completed, continue to stand for 30 minutes at the same temperature;

[0034] (2) Rotary evaporation

[0035] Put the clear solution obtained in step (1) into a rotary evaporator until the water and excess amine are completely sublimated and escaped;

[0036] In particular, after the mixing reaction is complete, the solution is placed in a rotary evaporator at a temperature of 85°C, a rotating speed of 100r/min, and a time of 12 hours, until the excess water and amine are evaporated and escaped.

[0037] (3)Medium temperature solid-liquid reaction

[0038] After washing the soil contaminated by heavy metals, grind to fine particles (below 30 mesh), and dry at 60°C for use. The dried and sieved soil was mixed with triethylamine hydrogen sulfate ionic liquid in a ratio of 1:20, the temperature was 90°C, and the reaction time was 6 hours. After the reaction system is cooled to normal temperature, the soil sample is washed out with 97% ethanol solution and transferred to a 50mL centrifuge tube; centrifuge at 15°C, 2000xg rotation speed for 50 minutes to collect the ethanol centrifuge solution. The centrifugation process was repeated 3 times. After centrifugation, the soil was transferred to a cellulose sleeve, the ethanol centrifugal liquid was placed in a round-bottomed flask, and a Sox-type extraction device was used at 150°C for 20 hours to remove the ionic liquid residue in the soil sample.

[0039] It was detected that the removal rate of soil heavy metal As was 58%, the removal rate of Cd was 96.4%, the removal rate of Fe was 61.8%, the removal rate of Mn was 91.2%, and the removal rate of Zn was 67.1%.

Example Embodiment

[0040] Example 3

[0041] A method of using triethylamine hydrogen sulfate ionic liquid ([TEA][HSO4]) to remove heavy metals in plants, the steps are as follows:

[0042] (1) Preparation of ionic liquid

[0043] In a constant low temperature (4°C) ice water bath, 150ml of 5M concentrated sulfuric acid solution (95.0-98.0wt.%) was slowly added to 104.5ml of triethylamine solution (99wt.%). After the mixing is completed, continue to stand for 30 minutes at the same temperature;

[0044] (2) Rotary evaporation

[0045] Put the clear solution obtained in step (1) into a rotary evaporator until the water and excess amine are completely sublimated and escaped;

[0046] In particular, after the mixing reaction is complete, the solution is placed in a rotary evaporator at a temperature of 80° C., a rotation speed of 200 r/min, and a time of 10 hours, until the excess water and amine are evaporated and escaped.

[0047] (3)Medium temperature solid-liquid reaction

[0048] After washing plants (willow branches and leaves) growing in heavy metal contaminated soil, they are ground to fine particles (0.35 mm) and dried at 60°C for use. The dried and sieved plants are mixed with triethylamine hydrogen sulfate ionic liquid in a ratio of 1:30, the temperature is 90°C, and the reaction time is 8 hours. After the reaction system is cooled to normal temperature, the plant samples are washed out with 97% ethanol solution and transferred to a 50 mL centrifuge tube; centrifuge at 15° C., 2000xg rotation speed for 50 minutes to collect the ethanol centrifuge solution. The centrifugation process was repeated 3 times. After centrifugation, the plant sample was transferred to a cellulose sleeve, the ethanol centrifugal liquid was placed in a round bottom flask, and a Sox-type extraction device was used at 150°C for 20 hours to remove the ionic liquid residue in the plant sample.

[0049] It was detected that the removal rate of heavy metal Cd in plants was 72.66%, the removal rate of Zn was 89.47%, the removal rate of Fe was 74.51%, the removal rate of Mn was 87.53%, and the removal rate of Cu was 100%.

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