CN108264649B

CN108264649B - Recovery method of environment-friendly soil eluting agent PASP

Info

Publication number: CN108264649B
Application number: CN201810052684.8A
Authority: CN
Inventors: 胡晓钧; 汪波; 姜伟杰
Original assignee: Shanghai Institute of Technology
Current assignee: Shanghai Institute of Technology
Priority date: 2018-01-19
Filing date: 2018-01-19
Publication date: 2021-02-26
Anticipated expiration: 2038-01-19
Also published as: CN108264649A

Abstract

The invention discloses a method for recovering environment-friendly soil eluting agent PASP. The method comprises the following specific steps: adjusting the pH value of the polluted soil eluent to 7.0-7.5 by using a pH regulator; adding a TMT-18 heavy metal capture agent into the polluted soil eluent, and stirring for 1-5 h; standing for 1-3 hours after stirring is finished, and carrying out solid-liquid separation to obtain liquid; adding potassium chloride into the liquid obtained in the step (3) for salting out, drying the obtained precipitate, and recovering to obtain the environment-friendly soil eluting agent PASP. The invention uses TMT-18 heavy metal catching agent and salting-out method to realize the rapid recovery of PSAP (PSAP) of the environment-friendly eluent, the recovery rate of PASP of the soil eluent can reach more than 80%, and the recovery cost is low, the operation is simple and feasible, and no secondary pollution is caused.

Description

Recovery method of environment-friendly soil eluting agent PASP

Technical Field

The invention relates to a soil leaching remediation technology, in particular to a method for recovering an environment-friendly soil leaching agent PASP.

Background

Statistically, in the past half century or more, about 2.2 million tons of cadmium, 93.9 million tons of copper, 78.3 million tons of lead, and 135 million tons of zinc, which are heavy metals worldwide, are discharged into soil on which humans live, and some of them permeate into soil with wastewater, rainwater, and other ways, and over time, soil of different countries and regions on the earth has been contaminated to different degrees. In europe, the area of farmland soil contaminated with heavy metals alone has reached as many as several million hectares, and in japan in asia, the area of farmland soil contaminated has exceeded 6000 hectares. The heavy metal content of some vegetables in australia and bangladesh has exceeded locally established standards and the problem of mercury contamination in spain has raised local government concerns. However, it is feared that the soil area polluted by heavy metals in China is also very serious. At present, the total standard exceeding rate of soil in China is 16.1%, wherein the point standard exceeding rates of cadmium, mercury, arsenic, copper, lead, chromium, zinc and nickel are 7.0%, 1.6%, 2.7%, 2.1%, 1.5%, 1.1%, 0.9% and 4.8% respectively.

TMT-18 series heavy metal ion trapping agents are high-tech water treatment agents (organic sulfides) which are prepared by Wuhan Boren Dico science and technology Limited company based on scientific research forces of China university of science and technology and Hubei university of industry and combining actual water quality conditions of Chinese heavy metal ion wastewater with great concentration. The product can rapidly react with various heavy metal ions (mercury, lead, copper, nickel, manganese, zinc, chromium and the like) in the wastewater at normal temperature to generate chelate which is insoluble in water and has good chemical stability, so that the aim of capturing and removing heavy metals is fulfilled, and particularly the TMT-18F type has the advantages of no toxicity, no odor, no secondary pollution, no water body discoloration when a large amount of the product is input, and is suitable for various occasions for removing heavy metals.

PASP (polyaspartic acid sodium salt) is a water-soluble polymer substance artificially synthesized in a biomimetic manner, has the characteristics of no phosphorus, no toxicity, no public nuisance and biodegradability, and is an internationally recognized 'green chemical'. The polyaspartic acid has strong performance of chelating heavy metal due to the structural characteristics of active groups such as peptide bonds, carboxyl and the like, and has excellent compatibility; therefore, the water-based leaching agent is very suitable for being used as an eluting agent for polluted soil. Chinese invention patent (CN107011908A) reports the relevant condition of PASP as soil eluting agent. In the aspect of engineering application, from the aspect of cost saving, after the soil leaching is finished, the PASP soil leaching agent needs to be recycled.

Disclosure of Invention

The invention aims to provide a method for recovering an environment-friendly soil eluting agent PASP, which can quickly recover the soil eluting agent PASP in eluent and has high recovery efficiency.

The purpose of the invention is realized by the following technical scheme.

A method for recovering an environment-friendly soil eluting agent PASP comprises the following specific steps:

(1) adjusting the pH value of the polluted soil eluent to 7.0-7.5 by using a pH regulator;

(2) adding a TMT-18 heavy metal capture agent into the polluted soil eluent, and stirring for 1-5 h;

(3) standing for 1-3 hours after stirring is finished, and carrying out solid-liquid separation to obtain liquid;

(4) adding potassium chloride into the liquid obtained in the step (3) for salting out, drying the obtained precipitate, and recovering to obtain the environment-friendly soil eluting agent PASP.

In the invention, in the step (1), the pH regulator is 4-10 wt% NaOH solution or 4-10 wt% HNO₃And (3) solution.

In the invention, in the step (2), the mass-to-volume ratio of the TMT-18 heavy metal capture agent to the polluted soil eluent is 1: 8-1: 15 g/mL.

In the invention, in the step (2), the stirring speed is 160-250 r/min.

In the invention, in the step (3), the solid-liquid separation adopts a filtration separation or centrifugal separation mode.

In the invention, in the step (4), the drying temperature is 45-55 ℃.

Compared with the prior art, the invention has the beneficial effects that:

the invention can use TMT-18 as heavy metal trapping agent and salting-out method to realize the rapid recovery of PSAP (PSAP) of environment-friendly eluent, the recovery rate of PASP of soil eluent can reach more than 80%, and the recovery cost is low, the operation is simple and feasible, and no secondary pollution is caused.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the following examples.

Example 1

1. 5% NaOH and 5% HNO were used₃The solution is a pH value regulator which regulates the pH value of polluted soil eluent to 7, and the eluent is sourced from example 2 of Chinese invention patent (CN 107011908A);

2. weighing TMT-18 heavy metal capture agent with the weight (g) of polluted soil eluent (ml) of 1: 10;

3. adding 10 g of heavy metal capture agent TMT-18 into 100 ml of polluted soil eluent, and stirring at the speed of 180 revolutions per minute for 2 hours at room temperature;

4. standing for 2 hours, and filtering by using a suction filtration method to remove precipitates;

5. adding potassium chloride for salting out to generate precipitate in the PASP eluent;

6. placing the solution in a centrifuge tube, centrifuging for 10 minutes at the speed of 5000 rpm, and pouring out supernatant;

7. and (3) placing the PASP precipitate in an oven, and drying at 50 ℃ to obtain the recovered environment-friendly soil eluting agent PASP, wherein the recovery rate of the soil eluting agent PASP can reach more than 80%, and the purity of the recovered soil eluting agent PASP can reach more than 80% by measuring the purity of the recovered soil eluting agent by Differential Scanning Calorimetry (DSC).

Example 2

1. 8% NaOH and 8% HNO were used₃The solution is a pH value regulator which regulates the pH value of an eluent of the polluted soil to 7.5, wherein the eluent is sourced from example 1 of Chinese patent (CN 107011908A);

2. weighing TMT-18 heavy metal capture agent with the weight (g) of polluted soil eluent (ml) of 1: 8;

3. adding 50 g of heavy metal capture agent TMT-18 into 400 ml of polluted soil eluent, and stirring at room temperature at the speed of 160 r/min for 2 hours;

4. standing for 1 hour, and filtering by using a suction filtration method to remove precipitates;

Example 3

1. 5% NaOH and 5% HNO were used₃The solution is a pH value regulator which regulates the pH value of polluted soil eluent to 7, and the eluent is obtained from example 1 of Chinese patent (CN 107011908A);

2. weighing TMT-18 heavy metal capture agent with the weight (g) of polluted soil eluent (ml) being 1: 15;

3. adding 20 g of heavy metal capture agent TMT-18 into 300 ml of polluted soil eluent, and then stirring at the speed of 250 revolutions per minute for 2 hours at room temperature;

4. standing for 3 hours, and filtering by using a suction filtration method to remove precipitates;

Claims

1. The method for recovering the environment-friendly soil eluting agent PASP is characterized by comprising the following specific steps of:

(4) adding potassium chloride into the liquid obtained in the step (3) for salting out to obtain a precipitate, and drying the obtained precipitate to obtain the environment-friendly soil eluting agent PASP after recovery.

2. The recycling method according to claim 1, wherein in the step (1), the pH adjusting agent is 4 to 10 wt% NaOH solution or 4 to 10 wt% HNO₃And (3) solution.

3. The recovery method according to claim 1, wherein in the step (2), the mass-to-volume ratio of the TMT-18 heavy metal capture agent to the contaminated soil eluent is 1:8 to 1:15 g/mL.

4. The recycling method according to claim 1, wherein in the step (2), the stirring rate is 160-250 rpm.

5. The recovery method according to claim 1, wherein in the step (3), the solid-liquid separation is performed by filtration or centrifugation.

6. The recycling method according to claim 1, wherein in the step (4), the drying temperature is 45-55 ℃.