Modified activated carbon-microbial agent coupling body as well as preparation method and application thereof

Abstract

The invention discloses a modified activated carbon-microbial agent coupling body and a preparation method and application thereof, and belongs to the technical field of water environment pollution removal, and the method comprises the following steps: carbonizing dry coconut shell particles, and then activating to obtain activated carbon; modifying activated carbon to obtain modified activated carbon; in a sterile closed container, iso-butane is used as a unique carbon source and energy source, and rhodococcus rhodococcus is cultured on a minimum agar plate; putting the modified activated carbon on the minimum agar plate, and fully mixing the rhodococcus purpureus and the modified activated carbon to obtain a modified activated carbon-microbial agent coupling body; the modified activated carbon provided by the invention has rich porous structures and surface functional groups, provides efficient adsorption and enrichment of polycyclic aromatic hydrocarbons, effectively fixes rhodococcus purpureus capable of degrading polycyclic aromatic hydrocarbons, promotes colonization and growth of microorganisms by own carbon sources and trace elements, realizes green and efficient degradation of polycyclic aromatic hydrocarbons in water environment sediments, and has good application prospects. And the recovery of the river and lake ecosystem is accelerated.

Description

Technical Field

[0001] The invention relates to a modified activated carbon-microbial agent coupling body and a preparation method and application thereof, belonging to the technical field of water environment pollution removal. Background Art

[0002] PAHs are a class of organic pollutants that are difficult to degrade. They are widely present in water environments and easily enriched in sediments. The sources of PAHs include both natural generation and human activities. PAHs are mutagenic, teratogenic and carcinogenic, posing a major potential threat to the aquatic ecological environment, aquatic organisms and human health. It is worth noting that PAHs can enter the human body through the respiratory and digestive tracts and induce a variety of cancers. Therefore, how to effectively control PAH pollution in the water environment has become a hot topic of global concern.

[0003] At present, the methods for repairing PAH pollution in the water environment mainly include physical, chemical and biological remediation technologies. Physical remediation technologies such as sediment dredging can effectively remove contaminated sediments, but they are costly and may cause the risk of secondary pollution. Chemical remediation technology transforms PAHs through chemical oxidation or reduction reactions, which is effective, but requires a large amount of chemical reagents and harsh environmental conditions, and also has the risk of secondary pollution. Biological remediation technology uses microorganisms or plants to degrade or absorb PAHs, which has the advantages of low cost and environmental friendliness, but there are bottleneck problems such as long processing cycle and poor environmental adaptability. Due to the difficulty of degradation and environmental stability of PAHs, their remediation work still has certain challenges. Existing remediation technologies are mostly concentrated in a single method, resulting in low efficiency in the degradation of PAHs. Summary of the invention

[0004] The purpose of the present invention is to provide a modified activated carbon-microbial agent coupling body and a preparation method and application thereof, so as to solve the problem of low degradation efficiency of polycyclic aromatic hydrocarbons existing in the prior art.

[0005] To achieve the above objectives, the present invention is implemented by adopting the following technical solutions: In a first aspect, the present invention provides a method for preparing a modified activated carbon-microbial agent coupling body, comprising: The dried coconut shell particles are carbonized and then activated to obtain activated carbon; Modifying the activated carbon to obtain modified activated carbon; Rhodococcus rhodochrous was cultured on minimal agar plates in sterile closed containers with isobutane as the sole carbon and energy source; The modified activated carbon is placed on the minimum agar plate, and the Rhodococcus rhodochrous and the modified activated carbon are fully mixed to obtain a modified activated carbon-microbial agent coupling body.

[0006] Furthermore, the carbonizing of the dried coconut shell particles comprises: Put the dried coconut shell particles into a high-temperature furnace, set the heating rate to 10 ~ 20℃ / min, heat to 400 ~1000℃ and keep it warm for 2 ~ 6 hours, then take it out.

[0007] Furthermore, the activation comprises: adding an activator to the carbonized coconut shell particles, setting the ambient temperature to 800-1000°C, setting the ambient pressure to 0.2-0.5 MPa, the activator comprising phosphoric acid and potassium hydroxide, and the concentration of the activator being 1-6 mol / L.

[0008] Furthermore, the modified activated carbon is modified to obtain modified activated carbon, comprising: adding hydrogen peroxide to the activated carbon for surface oxidation treatment, wherein the concentration of the hydrogen peroxide is 3 to 6 wt %.

[0009] Furthermore, after obtaining the modified activated carbon, the method further includes a step of screening the modified activated carbon, wherein the screening of the modified activated carbon includes: screening the modified activated carbon to retain the modified activated carbon with a size of 200 to 800 μm.

[0010] Furthermore, the concentration of the isobutane is 1.4-1.6% v / v.

[0011] Furthermore, the culture conditions are: temperature of 28-32°C and time of 24-48h.

[0012] Furthermore, in the mixing step, the mass fraction of the modified activated carbon is 0.1 to 0.4 wt %.

[0013] In a second aspect, the present invention provides a modified activated carbon-microbial agent coupling body, which is prepared by any method described in the first aspect.

[0014] In a third aspect, the present invention provides an application of a modified activated carbon-microbial agent coupling body, wherein the modified activated carbon-microbial agent coupling body prepared by any of the methods described in the first aspect is evenly spread on the surface of sediment in a water environment, and then mixed into the sediment to remove polycyclic aromatic hydrocarbons; Among them, the spreading thickness of the modified activated carbon-microbial agent coupling body is 2~10cm, and the thickness of the sediment is 0.1~15cm.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. Coconut shell-based activated carbon is prepared from coconut shells. The raw materials come from natural coconuts and are very pure. They do not contain complex organic compounds or impurities such as heavy metals that may exist in raw materials such as coal and wood. They are more suitable for water environment applications and will not cause secondary pollution.

[0016] 2. After specific modification, coconut shell-based activated carbon has a highly dispersed microporous structure, huge specific surface area and rich surface functional groups. It can not only efficiently adsorb trace pollutants in the enriched water environment, which is beneficial to the direct removal of pollutants and the subsequent microbial degradation process; it can also provide microorganisms with sufficient habitat space and attachment sites, which is beneficial to the fixation and reproduction of functional microorganisms; finally, it is also rich in trace elements and nutrients, which is beneficial to the growth and metabolism of functional microorganisms, greatly improving the removal efficiency of polycyclic aromatic hydrocarbons in the water environment.

[0017] 3. After specific modification, the surface chemical properties of coconut shell-based activated carbon are changed, thereby improving the adsorption and selectivity of PAHs. This adsorption technology is not only efficient, fast and environmentally friendly, but can remove a large number of PAHs from sediments in a short time, reducing the repair cycle, and the adsorption process does not require the addition of chemical reagents, avoiding the generation of secondary pollution, and is highly safe for aquatic ecosystems.

[0018] 4. Rhodococcus rhodochrous has excellent tolerance to harsh environments, diverse metabolic pathways, and the ability to express a variety of enzymes that transform environmental pollutants. Rhodococcus rhodochrous (ATCC 21198) has the ability to effectively repair polycyclic aromatic hydrocarbons pollutants. In the sediment remediation process, the strain can significantly accelerate the degradation of polycyclic aromatic hydrocarbons through effective fixation and growth promotion of modified coconut shell-based activated carbon, showing good application potential.

[0019] 5. The prepared coupling body utilizes the combination of in-situ remediation and bioremediation, and the adsorption, carrier and degradation of modified coconut shell-based activated carbon form a synergistic effect. Compared with traditional methods, the use of this coupling body to remove polycyclic aromatic hydrocarbons has the advantages of low cost, long-lasting effect, environmental friendliness, and high efficiency in degrading organic matter, which is conducive to the rapid recovery of the ecological environment of rivers and lakes and sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the preparation and degradation process provided by an embodiment of the present invention; Figure 2 It is a comparative schematic diagram of the degradation rates of several polycyclic aromatic hydrocarbons such as naphthalene, phenanthrene and pyrene detected after adding the modified activated carbon-microbial agent coupling body in the water environment provided by the embodiment of the present invention; Figure 3 It is a comparative schematic diagram of the degradation rates of polycyclic aromatic hydrocarbons detected after adding modified activated carbon-microbial agent coupling body, modified activated carbon and Rhodococcus rhodochrous in the water environment provided by the embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the protection scope of the present invention.

[0022] Example 1.

[0023] like Figure 1 As shown, the present invention provides a modified activated carbon-microbial agent coupling body, comprising the following steps: Step 1: Grind the dried coconut shell into uniform particles, and then put it into a high-temperature furnace for carbonization. The conditions for the carbonization treatment are: heating rate of 10°C / min, rising to 400°C and keeping warm for 2 hours, adding phosphoric acid activator to the carbonized coconut shell for activation treatment. The conditions for the activation treatment are: temperature of 800°C, pressure of 0.2 MPa, and concentration of phosphoric acid activator of 2 mol / L.

[0024] Step 2: Add hydrogen peroxide to the activated carbon for surface oxidation treatment to further improve the performance of the activated carbon. The concentration of hydrogen peroxide is 3wt%. Finally, screening is performed to obtain modified activated carbon that meets the particle size requirements. The particle size of the activated carbon after screening is 200 ~ 800um.

[0025] Step 3: In a sterile sealed container, 1.5% v / v isobutane is used as the only carbon source and energy source, and Rhodococcus rhodochrous ATCC 21198 is cultured on a minimal agar plate under the following culture conditions: temperature of 30°C and time of 24 hours.

[0026] Step 4: Add the sieved modified activated carbon to the agar plate for culturing Rhodococcus rhodochrous and mix them thoroughly. The mass fraction of the added modified activated carbon is 0.1wt%, and finally a modified activated carbon-microbial agent coupling body is obtained.

[0027] The modified activated carbon-microbial agent coupling body prepared in Example 1 was evenly spread on the sediment surface with a spreading thickness of 2 cm; and a rotary mechanical mixing unit was used to mix it into the near-surface sediment and into a 5 cm sediment layer.

[0028] Example 2.

[0029] The present invention provides a modified activated carbon-microbial agent coupling body, comprising the following steps: Step 1: Grind the dried coconut shell into uniform particles, and then put it into a high-temperature furnace for carbonization. The conditions of the carbonization treatment are: heating rate of 15°C / min, rising to 700°C and keeping warm for 4 hours, adding phosphoric acid activator to the carbonized coconut shell for activation treatment. The conditions of the activation treatment are: temperature of 900°C, pressure of 0.4 MPa, and concentration of phosphoric acid activator of 4 mol / L; Step 2: adding hydrogen peroxide to the activated carbon for surface oxidation treatment to further improve the performance of the activated carbon. The concentration of hydrogen peroxide is 5wt%. Finally, screening is performed to obtain modified activated carbon that meets the particle size requirements. The particle size of the activated carbon after screening is 300 ~ 500um. Step 3: In a sterile sealed container, 1.5% v / v isobutane was used as the sole carbon source and energy source to culture Rhodococcus rhodochrous ATCC 21198 on a minimal agar plate under the following culture conditions: temperature 30°C, time 36 h; Step 4: Add the sieved modified activated carbon to the agar plate for culturing Rhodococcus rhodochrous and mix them thoroughly. The mass fraction of the added modified activated carbon is 0.3wt%, and finally a modified activated carbon-microbial agent coupling body is obtained.

[0030] The modified activated carbon-microbial agent coupling body prepared in Example 2 was evenly spread on the sediment surface with a spreading thickness of 8 cm; and a rotary mechanical mixing unit was used to mix it into the near-surface sediment and into a 10 cm sediment layer.

[0031] like Figure 2 As shown in the figure, within one month of using the modified activated carbon-microbial agent coupling body to remediate PAHs in the water environment, the degradation rates of naphthalene, phenanthrene, and pyrene, which are difficult to degrade PAHs, can reach more than 90%. Figure 3 As shown, compared with the use of modified activated carbon and Rhodococcus rhodochrous alone, the modified activated carbon-microbial agent coupling body showed more outstanding efficiency in degrading polycyclic aromatic hydrocarbons in the water environment, which also fully demonstrated that the modified activated carbon-microbial agent coupling body can greatly improve the degradation efficiency of polycyclic aromatic hydrocarbons.

[0032] The present invention significantly improves the degradation rate of polycyclic aromatic hydrocarbons by applying the modified activated carbon-microbial agent coupling body to the remediation of organic polycyclic aromatic hydrocarbons in the water environment, effectively improves the recovery of the aquatic ecosystem, makes the water environment healthier, and is conducive to the rapid recovery and sustainable development of river and lake ecosystems.

[0033] More specific beneficial effects and principle analysis are as follows: After specific modification, coconut shell-based activated carbon has a highly dispersed microporous structure, a huge specific surface area and abundant surface functional groups. It can not only efficiently adsorb trace pollutants in the enriched water environment, but also provide sufficient habitat space and attachment sites for microorganisms. It is rich in trace elements and nutrients, supports the rapid colonization and growth of microorganisms, and is an excellent microbial carrier. It is worth noting that coconut shell-based activated carbon comes from natural coconuts, is relatively pure, and does not contain complex organic compounds or impurities such as heavy metals that may exist in raw materials such as coal and wood, making it more suitable for water environment applications. At the same time, studies have found that Rhodococcus rhodochrous ATCC 21198 has a wide range of metabolic capabilities due to its tolerance to harsh environments. It can effectively transform a variety of environmental pollutants, including difficult-to-degrade polycyclic aromatic hydrocarbons, and has great application potential in the bioremediation of polycyclic aromatic hydrocarbons. Based on this, the present invention proposes a modified activated carbon-microbial agent coupling body and its preparation method and application, which is expected to become an economical, efficient and environmentally friendly new way to treat polycyclic aromatic hydrocarbons pollution in water environments.

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a modified activated carbon-microbial agent coupling body, characterized in that: include: The dried coconut shell particles are carbonized and then activated to obtain activated carbon; Modifying the activated carbon to obtain modified activated carbon; Rhodococcus rhodochrous was cultured on minimal agar plates in sterile closed containers with isobutane as the sole carbon and energy source; The modified activated carbon is placed on the minimum agar plate, and the Rhodococcus rhodochrous and the modified activated carbon are fully mixed to obtain a modified activated carbon-microbial agent coupling body.

2. The method for preparing the modified activated carbon-microbial agent coupling body according to claim 1, characterized in that: The method of carbonizing the dried coconut shell particles comprises: Put the dried coconut shell particles into a high-temperature furnace, set the heating rate to 10 ~ 20℃ / min, heat to 400 ~ 1000℃ and keep it warm for 2 ~ 6 hours, then take it out.

3. The method for preparing the modified activated carbon-microbial agent coupling body according to claim 1, characterized in that: The activation comprises: adding an activator to the carbonized coconut shell particles, setting the ambient temperature to 800-1000°C, setting the ambient pressure to 0.2-0.5 MPa, the activator comprising phosphoric acid and potassium hydroxide, and the concentration of the activator being 1-6 mol / L.

4. The method for preparing the modified activated carbon-microbial agent coupling body according to claim 1, characterized in that: The modified activated carbon includes: adding hydrogen peroxide to the activated carbon for surface oxidation treatment, wherein the concentration of the hydrogen peroxide is 3-6wt%.

5. The method for preparing the modified activated carbon-microbial agent coupling body according to claim 1, characterized in that: After obtaining the modified activated carbon, the method further includes a step of screening the modified activated carbon, wherein the screening of the modified activated carbon includes: screening the modified activated carbon to retain the modified activated carbon with a size of 200 to 800 μm.

6. The method for preparing the modified activated carbon-microbial agent coupling body according to claim 1, characterized in that: The concentration of the isobutane is 1.4-1.6% v / v.

7. The method for preparing the modified activated carbon-microbial agent coupling body according to claim 1, characterized in that: The culture conditions are: temperature of 28-32°C and time of 24-48h.

8. The method for preparing the modified activated carbon-microbial agent coupling body according to claim 1, characterized in that: In the mixing step, the mass fraction of the modified activated carbon is 0.1 to 0.4wt%.

9. A modified activated carbon-microbial agent coupling body, characterized in that: The method is prepared by any one of claims 1 to 8.

10. An application of a modified activated carbon-microbial agent coupling body, characterized in that: The modified activated carbon-microbial agent coupling body prepared by the method according to any one of claims 1 to 8 is evenly spread on the surface of sediment in the water environment, and then mixed into the sediment to remove polycyclic aromatic hydrocarbons; Among them, the spreading thickness of the modified activated carbon-microbial agent coupling body is 2~10cm, and the thickness of the sediment is 0.1~15cm.

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