Method for efficient conversion of soil weak-acid-bound cadmium by compoundbacterial agent

Abstract

The invention relates to a method for efficient conversion of soil weak-acid-bound cadmium by compoundbacterial agent. The compound bacterial agent is obtained by mixing and enrichment culture of two floras as follows: (1) aflora I comprising candida, phialemonium,rhodosporidium toruloides and cryptococcus; (2) a flora II comprising acidithiobacillus thiooxidans, leptospirillum ferrooxidans, acidithiobacillus caldus,sulfobacillus thermosulfidooxidans, acidithiobacillus ferrooxidansand ferroplasma thermophilum. The obtained compoundbacterial agent is guided into cadmium polluted soil after culture, cadmium is fully reacted after stirring for a certain time, and cadmium can be efficiently converted into soil weak-acid-bound cadmium.

Description

technical field

[0001] The invention relates to a microbiological method for treating heavy metal cadmium, which utilizes green biotechnology, especially a method for efficiently converting soil weak acid-bound cadmium by using a compound bacterial agent. Background technique

[0002] In recent years, soil heavy metal remediation is more and more biased towards bioremediation, among which phytoremediation is more common, but factors such as domestication and cultivation of high-enrichment plants and long growth cycles limit the development of phytoremediation, while bioleaching has the advantages of cost-effectiveness stand out. Bioleaching technology has long been widely used in the field of metallurgy. However, due to the complex soil system and various forms of heavy metals, bioleaching technology has not yet been involved in the treatment of heavy metals in soil. Most of them are limited to laboratory shake flask leaching. is difficult to achieve.

[0003] Soil polluti...

Examples

Embodiment 1

[0028] Embodiment 1: collection, cultivation and domestication of cadmium-tolerant microorganisms

[0029]Group 1 consists of 71.5% Candida, 13.5% Phialemonium, 10% Rhodosporidium toruloides, 5% Cryptococcus; Candida (Candida) includes Candida parapsilosis (Candida parapsilosis), Tropical Candida (Candidatropicalis) and stout Candida (Candida valida), the number ratio of the three bacteria is 5:2:3; Cryptococcus (Cryptococcus) includes The ratio of Cryptococcus laurentii, Cryptococcus victoriae and Filobasidiella bacillispora is 3:2:2;

[0030] Before mixing, the bacteria were respectively acclimatized in cadmium-containing medium. The specific steps and conditions of acclimation were as follows: put the bacteria in 100mL sterilized medium containing 10% 9K, 8‰ glucose, 4‰ sulfur powder and a concentration gradient of 0.5mmol / L, 1.0mmol / L, 1.5mmol / L, 2.0mmol / L, ..., 14.5mmol / L, 15.0mmol / L CdSO 4 In the culture medium, acclimate 30 generations under the condition of rotation...

Embodiment 2

[0036] In this embodiment, the field effect verification is carried out in the experimental soil. The situation is as follows. Take the polluted farmland soil in the VIP experimental demonstration area of ​​environmental governance in Beishan Town, Changsha City, Hunan Province, and measure the Cd content in the soil for 3 times. The average value is 2.31ppm. The specific steps of applying the microbial preparation of the present invention are as follows: ① uniformly apply the microbial preparation on the polluted soil surface area according to the ratio of 40L / mu-60L / mu. ②Use an agricultural tiller to plow the ground for 1 hour, settle overnight and then drain to the recovery pond to measure the cadmium content in the soil. ③ Repeat steps ① and ② once every 1-2 days, and the microbial preparations can be recycled, that is, the cadmium in the solution has been recycled to treat the microbial preparations. Repeating this treatment three times can restore the soil polluted by he...

technical field

[0001] The invention relates to a microbiological method for treating heavy metal cadmium, which utilizes green biotechnology, especially a method for efficiently converting soil weak acid-bound cadmium by using a compound bacterial agent. Background technique

[0002] In recent years, soil heavy metal remediation is more and more biased towards bioremediation, among which phytoremediation is more common, but factors such as domestication and cultivation of high-enrichment plants and long growth cycles limit the development of phytoremediation, while bioleaching has the advantages of cost-effectiveness stand out. Bioleaching technology has long been widely used in the field of metallurgy. However, due to the complex soil system and various forms of heavy metals, bioleaching technology has not yet been involved in the treatment of heavy metals in soil. Most of them are limited to laboratory shake flask leaching. is difficult to achieve.

[0003] Soil polluti...

Examples

Embodiment 1

[0028] Embodiment 1: collection, cultivation and domestication of cadmium-tolerant microorganisms

[0029]Group 1 consists of 71.5% Candida, 13.5% Phialemonium, 10% Rhodosporidium toruloides, 5% Cryptococcus; Candida (Candida) includes Candida parapsilosis (Candida parapsilosis), Tropical Candida (Candidatropicalis) and stout Candida (Candida valida), the number ratio of the three bacteria is 5:2:3; Cryptococcus (Cryptococcus) includes The ratio of Cryptococcus laurentii, Cryptococcus victoriae and Filobasidiella bacillispora is 3:2:2;

[0030] Before mixing, the bacteria were respectively acclimatized in cadmium-containing medium. The specific steps and conditions of acclimation were as follows: put the bacteria in 100mL sterilized medium containing 10% 9K, 8‰ glucose, 4‰ sulfur powder and a concentration gradient of 0.5mmol / L, 1.0mmol / L, 1.5mmol / L, 2.0mmol / L, ..., 14.5mmol / L, 15.0mmol / L CdSO 4 In the culture medium, acclimate 30 generations under the condition of rotation...

Embodiment 2

[0036] In this embodiment, the field effect verification is carried out in the experimental soil. The situation is as follows. Take the polluted farmland soil in the VIP experimental demonstration area of ​​environmental governance in Beishan Town, Changsha City, Hunan Province, and measure the Cd content in the soil for 3 times. The average value is 2.31ppm. The specific steps of applying the microbial preparation of the present invention are as follows: ① uniformly apply the microbial preparation on the polluted soil surface area according to the ratio of 40L / mu-60L / mu. ②Use an agricultural tiller to plow the ground for 1 hour, settle overnight and then drain to the recovery pond to measure the cadmium content in the soil. ③ Repeat steps ① and ② once every 1-2 days, and the microbial preparations can be recycled, that is, the cadmium in the solution has been recycled to treat the microbial preparations. Repeating this treatment three times can restore the soil polluted by he...