阅读说明：本技术 一种改性生物炭及其制备方法和应用 (Modified biochar and preparation method and application thereof ) 是由 李静 赵晋灵 钟帅 庞瑞 于 2020-04-29 设计创作，主要内容包括：本申请提供一种改性生物炭及其制备方法和应用。其中,改性生物炭的制备方法包括：选取棉花秸秆,并对棉花秸秆进行碳化处理,获得棉花秸秆生物炭；选取碱性溶液对所述棉花秸秆生物炭进行浸泡处理,获得初始改性生物炭；对所述初始改性生物炭进行抽滤和烘干处理,获得目标改性生物炭。进而可以对碱性重金属污染的土壤进行修复,治理土壤碱性重金属污染的问题。(The application provides modified biochar and a preparation method and application thereof. The preparation method of the modified biochar comprises the following steps: selecting cotton straws, and carbonizing the cotton straws to obtain cotton straw biochar; selecting an alkaline solution to soak the cotton straw biochar to obtain initial modified biochar; and carrying out suction filtration and drying treatment on the initial modified biochar to obtain the target modified biochar. And further, the soil polluted by the alkaline heavy metal can be repaired, and the problem of the alkaline heavy metal pollution of the soil can be solved.)

1. A preparation method of modified biochar is characterized by comprising the following steps:

selecting cotton straws, and carbonizing the cotton straws to obtain cotton straw biochar;

selecting an alkaline solution to soak the cotton straw biochar to obtain initial modified biochar;

and carrying out suction filtration and drying treatment on the initial modified biochar to obtain the target modified biochar.

2. The preparation method of the modified biochar as claimed in claim 1, wherein the volume ratio of the cotton straw biochar to the alkaline solution is 1: 100-200.

3. The preparation method of the modified biochar as claimed in claim 1, wherein the carbonizing treatment of cotton stalks to obtain the cotton stalk biochar comprises:

and firing the cotton straws to 600-700 ℃, and then carbonizing to obtain the cotton straw biochar.

4. The method for preparing modified biochar as claimed in claim 3, wherein the step of firing the cotton straw to 600-700 ℃ and then carbonizing the fired cotton straw to obtain the modified biochar comprises the following steps:

cleaning the cotton straws, and cutting the cotton straws into 1-6cm straw sections;

and firing the straw sections, carbonizing the straw sections for 3-5h after firing to 600-700 ℃, cooling to room temperature, taking out the straw sections, and sealing and storing the straw sections to obtain the cotton straw biochar.

5. The method for preparing modified biochar according to claim 1, wherein the soaking treatment of the cotton straw biochar by the selected alkaline solution to obtain initial modified biochar comprises the following steps:

and (3) selecting 2-5mol/L sodium hydroxide solution to soak the cotton straw biochar for 24-48h, and washing with ultrapure water until the pH value is not changed any more, thereby obtaining the initial modified biochar.

6. The method for preparing modified biochar according to claim 1, wherein the step of performing suction filtration and drying treatment on the initial modified biochar to obtain target modified biochar comprises the following steps:

and carrying out suction filtration on the initial modified biochar, and drying at 50-80 ℃ to obtain the target modified biochar.

7. A modified biochar, characterized in that it is prepared by the process according to any one of claims 1 to 6.

8. Use of the modified biochar of claim 7 in remediation of soil contaminated with alkaline heavy metals by applying the modified biochar to the soil contaminated with alkaline heavy metals.

9. The use according to claim 8, wherein the modified biochar of claim 7 is applied to alkaline cadmium-contaminated soil to remediate the alkaline cadmium-contaminated soil.

Technical Field

The application relates to the technical field of soil remediation, in particular to modified biochar and a preparation method and application thereof.

Background

Since the discovery of cadmium in the early 20 th century, the production of cadmium has increased year by year. Cadmium is a byproduct in the zinc smelting industry, is mainly used in batteries, dyes or plastic stabilizers, is widely applied to the fields of electroplating industry, chemical industry, electronic industry, nuclear industry and the like, and is easier to be adsorbed by crops than other heavy metals.

At present, more and more cadmium is discharged into the environment through waste gas, waste water and waste residues to cause pollution, the pollution sources are mainly lead-zinc ores, non-ferrous metal smelting, electroplating, factories using cadmium compounds as raw materials or catalysts and the like, so that the heavy metal pollution condition of cultivated land in agricultural production areas in China is serious, and the cadmium content of rice in regions such as Hunan, Guangdong, Guangxi, Fujian, Zhejiang and the like exceeds 5-15% of the national food safety standard.

The pH of the soil is in a negative correlation with the cadmium effectiveness, the cadmium bioavailability on the alkaline polluted soil is lower than that on the acid soil, but the passivation and repair work of the alkaline heavy cadmium polluted soil is more difficult. Therefore, how to repair the cadmium-polluted soil becomes an urgent problem to be solved.

Disclosure of Invention

In view of this, the embodiment of the present application provides a modified biochar, and a preparation method and an application thereof, so as to solve technical defects in the prior art.

The application discloses a preparation method of modified biochar, which comprises the following steps:

selecting cotton straws, and carbonizing the cotton straws to obtain cotton straw biochar;

selecting an alkaline solution to soak the cotton straw biochar to obtain initial modified biochar;

and carrying out suction filtration and drying treatment on the initial modified biochar to obtain the target modified biochar.

Further, the volume ratio of the cotton straw biochar to the alkaline solution is 1: 100-200.

Further, the carbonizing treatment of the cotton straw to obtain the cotton straw biochar comprises the following steps:

and firing the cotton straws to 600-700 ℃, and then carbonizing to obtain the cotton straw biochar.

Further, the step of firing the cotton straws to 600-700 ℃ and then carbonizing to obtain the cotton straw biochar comprises the following steps:

cleaning the cotton straws, and cutting the cotton straws into 1-6cm straw sections;

and firing the straw sections, carbonizing the straw sections for 3-5h after firing to 600-700 ℃, cooling to room temperature, taking out the straw sections, and sealing and storing the straw sections to obtain the cotton straw biochar.

Further, the step of selecting an alkaline solution to soak the cotton straw biochar to obtain initial modified biochar comprises the following steps:

and (3) selecting 2-5mol/L sodium hydroxide solution to soak the cotton straw biochar for 24-48h, and washing with ultrapure water until the pH value is not changed any more, thereby obtaining the initial modified biochar.

Further, the step of performing suction filtration and drying treatment on the initial modified biochar to obtain target modified biochar comprises the following steps:

and carrying out suction filtration on the initial modified biochar, and drying at 50-80 ℃ to obtain the target modified biochar.

The application also discloses modified biochar which is prepared by the method.

The application also discloses an application of the modified biochar, and the modified biochar is applied to the soil polluted by the alkaline heavy metal to restore the soil polluted by the alkaline heavy metal.

Further, the modified biochar is applied to the soil polluted by the alkaline cadmium, and the soil polluted by the alkaline cadmium is repaired.

The application provides a modified biological charcoal obtains through utilizing alkaline solution to the cotton stalk modification, can improve the pH valve of self on the one hand, and then helps improving the pH valve of soil after applying into soil to reduce the mobility of heavy metal in soil, on the other hand can also improve its self adsorption efficiency and passivation ability, and then helps reducing the toxicity of heavy metal, improves soil repair ability.

According to the preparation method of the modified biochar, the cotton straws are carbonized, the adsorption capacity, the passivation capacity and other performances of the modified biochar can be effectively improved, the cotton straw biochar is soaked by selecting the alkaline solution, the pH value of the modified biochar can be effectively improved, and the soil restoration capacity of the modified biochar is further improved.

The application of the modified charcoal that this application provided, with this application the modified charcoal administer to alkaline heavy metal contaminated soil in, modified charcoal can improve the pH valve of soil, reduces the mobility of heavy metal in soil, can also further reduce the toxicity of heavy metal in the soil through modes such as electrostatic absorption, complexation, redox, and then restore alkaline heavy metal contaminated soil, administer the problem of soil alkaline heavy metal contamination.

Drawings

FIG. 1 is a schematic flow chart of the steps of a process for the preparation of modified biochar as described in example 1 of the present application;

FIG. 2 is a bar graph comparing the effective chromium content of the control and test groups as described in test example 1 of the present application.

Detailed Description

The following description of specific embodiments of the present application refers to the accompanying drawings.