CN111548803B

CN111548803B - Soil conditioner and preparation method and application thereof

Info

Publication number: CN111548803B
Application number: CN202010476150.5A
Authority: CN
Inventors: 朱英; 张爱生; 邵艳秋; 邵莹莹; 李静; 王启春
Original assignee: Shandong Shanke Ecological Environment Research Institute Co ltd; New Material Institute of Shandong Academy of Sciences
Current assignee: Shandong Shanke Ecological Environment Research Institute Co ltd; New Material Institute of Shandong Academy of Sciences
Priority date: 2020-05-29
Filing date: 2020-05-29
Publication date: 2021-12-17
Anticipated expiration: 2040-05-29
Also published as: CN111548803A

Abstract

The invention provides a soil conditioner and a preparation method and application thereof, belonging to the technical field of soil improvement. The soil conditioner is granular and is prepared from urban sludge composted materials, clay powder and CMC-MnO₂Mixing the nanometer particles. Not only directly use in farmland park heavy metal contaminated soil, get rid of multiple heavy metal, can also adsorb in later stage and get rid of some organic pollutants, can also provide the required nutrient element of soil simultaneously, improve soil environment, improve agricultural output. Therefore, it has good practical application value.

Description

Soil conditioner and preparation method and application thereof

Technical Field

The invention belongs to the technical field of soil improvement, and particularly relates to a soil conditioner and a preparation method and application thereof.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

Soil is one of the indispensable conditions for living of organisms and also an important component of ecological environment. With the utilization of soil by human social activities, pollutants or organic pollutants containing heavy metals enter the soil through various ways, so that corresponding heavy metal elements and organic pollutants in the soil are enriched. Heavy metals can exist in farmlands, rivers, lakes, marine water bodies and bottom sediments for a long time, and the heavy metals in soil exceed standards for a long time, so that the heavy metals in crops and aquatic products are accumulated excessively, the crops are reduced in yield and even die, and the human health is harmed through a food chain. The farmland soil heavy metal overproof elements in China under different research scales have obvious differences, and the farmland soil Cd element has the highest pollution probability.

The soil heavy metal pollution has the characteristics of concealment, long-term property and irreversibility, and the existing soil heavy metal pollution remediation technology comprises an engineering physical method, chemical remediation and biological remediation. However, these methods have certain disadvantages, for example, engineering restoration includes a soil-covering method, a leaching method, and an electric restoration method, but the soil-covering method has the disadvantages of large construction amount, high investment cost, soil structure destruction, soil fertility reduction, and piling or treating of the changed contaminated soil. The leaching method has a good treatment effect on the heavily polluted soil, but is easy to cause underground water pollution, and although heavy metal ions can be leached out of the soil, nutrient elements in the soil can be leached out, so that the soil fertility is reduced. The electric restoration method has high requirements on soil properties and is suitable for low-permeability clay and silt soil.

The chemical remediation is mainly characterized in that the water solubility, diffusivity and biological effectiveness of soil heavy metal pollutants can be reduced by applying the conditioner, and the harm of heavy metals to the ecological environment is reduced. Mainly comprises a precipitation method, an adsorbent addition method and an antagonism method. The chemical modifier has better modifying effect and moderate cost, and different modifiers are selected according to different heavy metal pollution and soil conditions, so that the chemical modifier is suitable for moderate pollution areas. However, the addition of the reagent is highly required, and if the reagent is not properly treated, secondary pollution is caused.

Bioremediation is a new method for treating contaminated soil by using biotechnology, and biological reduction and purification of heavy metals in soil or reduction of heavy metal toxicity are utilized. Mainly comprises microbial remediation and agricultural ecological remediation. Such as microbial engineering bacteria, EM beneficial microorganisms, an ecological protection system and the like. The method has good effect and easy operation, is increasingly paid attention by people, and becomes a hotspot of contaminated soil remediation research. But the agricultural ecological restoration of the polluted soil has long period and insignificant effect.

At present, the problem of heavy metal pollution of soil is more and more serious, and researches on the technology for repairing the heavy metal pollution of the soil are more and more concerned by researchers. The characteristics (such as types, forms, concentrations and the like) of pollutants, soil conditions (such as pH, permeability, underground water and the like), pollution degree, expected remediation targets are different, practical limitations, cost, application range of remediation technologies and other factors are also factors which become limitations of the selected remediation technologies, and the inventor finds that the high-efficiency and low-consumption soil heavy metal conditioner is difficult to have.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a soil conditioner and a preparation method and application thereof. The soil conditioner of the invention is prepared from municipal sludge composted product, clay powder and CMC-MnO₂The nano particles are prepared by mixing according to the weight ratio, can be directly used in heavy metal contaminated soil of farmlands and parks to remove various heavy metals, can adsorb and remove some organic pollutants at the later stage, and can provide nutrient elements required by the soil, improve the soil environment and improve the agricultural output. Therefore, it has good practical application value.

In order to solve the technical problems, the technical scheme of the invention is as follows:

in a first aspect of the invention, a soil conditioner is provided, wherein the soil conditioner is granular and is prepared from municipal sludge composted material, clay powder and CMC-MnO₂Mixing the nanometer particles.

Wherein the urban sludge composted material is prepared by uniformly mixing and fermenting dewatered sludge, peanut shells and compost backmixing materials.

The CMC-MnO₂The nanoparticles are made of carboxymethyl celluloseSodium vitamin solution and MnCl₂Preparation of solutions containing CMC-Mn²⁺A mixture of the complexes; then KMnO₄And NaOH are added into the mixture, and the mixture is shaken for reaction.

In a second aspect of the present invention, there is provided a process for producing the soil conditioner as described above, which comprises composting the municipal sludge, clay powder and CMC-MnO₂And (4) mixing the nano particles.

In a third aspect of the invention, there is provided the use of a soil amendment as described above in any one or more of:

a) improving the soil;

b) adsorbing heavy metals in soil;

c) adsorbing and degrading organic pollutants in soil;

d) promoting the growth of plants.

The beneficial technical effects of one or more technical schemes are as follows:

the soil conditioner provided by the technical scheme changes waste into valuable by utilizing the municipal sludge, and effectively improves the resource utilization rate. The organic fertilizer is directly applied to heavy metal contaminated soil in a farmland park, so that various heavy metals can be removed, some organic pollutants can be adsorbed and removed, the root system environment of crops is improved, and the agricultural production value is improved. Meanwhile, the preparation method of the technical scheme is simple and cheap, is simple and convenient to operate, and has good practical application value.

Detailed Description

It is to be understood that the following detailed description is exemplary and is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

In one embodiment of the present invention, a soil pollution improver is provided. The soil pollution modifier is prepared from municipal sludge composted product, clay powder and CMC-MnO₂The nano particles are mixed according to the weight proportion. Research shows that CMC-MnO is utilized₂The adsorbability of the nano particles adsorbs heavy metal ions and toxic and harmful ions in the soil, and products obtained after sludge composting can provide nutrient elements for the soil and degrade partial pollutants in the soil, so that the characteristics of the soil are improved, plants are prevented from being poisoned, and the normal growth of the plants is promoted.

In yet another embodiment of the invention, a soil conditioner is provided, the soil conditioner being in the form of granules and being composed of municipal sludge composted material, clay powder, CMC-MnO₂Mixing the nanometer particles.

In yet another embodiment of the present invention, the municipal sludge composted material, clay powder and CMC-MnO₂The mass ratio of the nanoparticles is 4-6: 1-2: 1, preferably 5:2: 1.

Wherein the urban sludge composted material is prepared by uniformly mixing and fermenting dewatered sludge, peanut shells and compost backmixing materials. The dewatered sludge is specifically dewatered sludge obtained after treatment of an urban domestic sewage treatment plant. The mass ratio of the dewatered sludge to the peanut shells to the compost return material is 2-4: 1:1, preferably 3:1: 1.

the CMC-MnO₂The nano-particles are prepared from sodium carboxymethyl cellulose solution and MnCl₂Preparation of solutions containing CMC-Mn²⁺A mixture of the complexes; then KMnO₄And NaOH are added into the mixture, and the mixture is shaken for reaction.

In another embodiment of the invention, the particle size of the soil conditioner particles is preferably not more than 2mm, which is beneficial to the slow release and effect of the conditioner.

In still another embodiment of the present invention, there is provided a method for preparing the soil conditioner as described above, which comprises composting the municipal sludge with the post-composting material, clay powder and CMC-MnO₂Nano-particlesAnd (4) mixing the granules.

The preparation method of the urban sludge composted material comprises the following steps: uniformly mixing the dewatered sludge, the peanut shells and the compost return material, and fermenting;

the mass ratio of the dewatered sludge to the peanut shells to the compost return material is 2-4: 1:1, preferably 3:1: 1.

the specific fermentation method of the urban sludge composted material comprises the following steps: spraying water to the mixed materials, stirring to make the water content of the mixed materials be 55-60%, turning the piles every two to three days to ensure the oxygen content of the piles, spraying water every two weeks, uniformly turning and continuing to ferment; the preparation is successful after about two months, and the product is soft, non-sticky and gray black.

The CMC-MnO₂The preparation method of the nano-particles comprises the following steps:

respectively preparing sodium carboxymethylcellulose (CMC) solution and MnCl₂Blowing the solution by nitrogen; then, MnCl was added under nitrogen purge₂Adding the solution into CMC solution to prepare the solution containing CMC-Mn²⁺A mixture of the complexes;

will contain KMnO₄Adding the stock solution of NaOH into the mixture drop by drop, and simultaneously carrying out oscillation treatment to obtain CMC-MnO₂Standing the nano-particle suspension, and separating to obtain CMC-MnO₂And (3) nanoparticles.

In another embodiment of the present invention, the specific conditions of the oscillation process are as follows: oscillating and reacting for 10-30 min at 200-300 rpm, preferably oscillating and reacting for 20min at 25 rpm.

In yet another embodiment of the present invention,

the concentration of the sodium carboxymethylcellulose (CMC) solution is 10-60 mg/L;

the MnCl₂The concentration of the solution is 2-5 mM;

the KMnO₄The concentration of the solution is 2-5 mM;

the concentration of the NaOH solution is 4-10 mM.

The CMC-MnO₂The concentration of the nanoparticle suspension is 0.2-2 mM. By controlling the addition concentration and reaction conditions of the raw materials, the CMC-MnO with proper shape and size can be obtained₂NanoparticlesAnd the capability of adsorbing heavy metal pollution is improved.

In another embodiment of the present invention, there is provided a use of the soil conditioner described above in any one or more of:

a) improving the soil;

b) adsorbing heavy metals in soil;

c) adsorbing and degrading organic pollutants in soil;

d) promoting the growth of plants.

The soil conditioner can effectively remove heavy metal pollution of soil, can degrade partial pollutants in the soil due to the activity of microorganisms in a sludge composted product after being applied for a period of time, provides some nutrient elements required by the soil, improves the microbial environment of the soil, improves the soil fertilizer and finally promotes the growth of crops.

The invention is further illustrated by the following examples, which are not to be construed as limiting the invention thereto. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Example 1

A soil pollution improver is prepared by the following steps:

(1) preparation of sludge compost product

Uniformly mixing 5 parts of municipal sludge, 1 part of peanut shell and 1 part of compost return material according to the weight ratio, spraying water, stirring until the water content is 60%, and fermenting; turning the pile every two to three days to ensure the oxygen content of the pile body, spraying water every two weeks and turning evenly and then continuing fermentation; the fermentation was continued for about two months.

(2)CMC-MnO₂Nanoparticle preparation

(at 0.4mmol/L CMC-MnO₂) For example, 55.6mg/L sodium carboxymethylcellulose (CMC) solution and 4mM MnCl were prepared₂The solution was purged with nitrogen for 20 min. Then, under a nitrogen purge, 3mL of MnCl₂The solution was added to 45mL of CMC solution to prepare a CMC-Mn-containing solution²⁺A mixture of the complexes. Then, the solution containing 4mM KMnO₄And 8mM NaOH 2mL stock solution was added drop-wise to the mixture while the reactor was shaken at 250rpmAnd (6) oscillating. After a continuous reaction for 20min, 50mL of 0.4mM CMC-MnO is obtained₂The nanoparticle suspension was kept still at room temperature (21. + -. 1) ℃ for 24 hours.

(3) Preparation of soil pollution improver

The sludge compost product, the clay powder and the CMC-MnO prepared by the method₂After the nano particles are mixed according to the weight ratio of 5:2:1, the mixture is prepared into particles with the particle size of about 2mm, which is beneficial to improving the slow release and the effect of the particles.

Example 2

A soil pollution improver is prepared by the following steps:

(1) preparation of sludge compost product

(2)CMC-MnO₂Nanoparticle preparation

(at 0.2mmol/L CMC-MnO₂) For example, 55.6mg/L sodium carboxymethylcellulose (CMC) solution and 2mM MnCl were prepared₂The solution was purged with nitrogen for 20 min. Then, under a nitrogen purge, 3mL of MnCl₂The solution was added to 45mL of CMC solution to prepare a CMC-Mn-containing solution²⁺A mixture of the complexes. Then, the solution containing 2mM KMnO₄And 4mM NaOH 2mL stock solution added drop wise to the mixture while the reactor was shaken at 250 rpm. After a continuous reaction for 20min, 50mL of 0.2mM CMC-MnO is obtained₂The nanoparticle suspension was kept still at room temperature (21. + -. 1) ℃ for 24 hours.

(3) Preparation of soil pollution improver

The sludge compost product, the clay powder and the CMC-MnO prepared by the method₂The nanoparticles are mixed according to a weight ratio of 5:2:1 to be prepared into particles with a particle size of about 2 mm.

Example 3

A soil pollution improver is prepared by the following steps:

(1) preparation of sludge compost product

(2)CMC-MnO₂Nanoparticle preparation

(at 2mmol/L CMC-MnO₂) For example, 11.12mg/L sodium carboxymethylcellulose (CMC) solution and 4mM MnCl were prepared₂The solution was purged with nitrogen for 20 min. Then, under a nitrogen purge, 3mL of MnCl₂The solution was added to 45mL of CMC solution to prepare a CMC-Mn-containing solution²⁺A mixture of the complexes. Then, the solution containing 4mM KMnO₄And 8mM NaOH 2mL stock solution added drop wise to the mixture while the reactor was shaken at 250 rpm. After a continuous reaction for 20min, 50mL of 2mM CMC-MnO is obtained₂The nanoparticle suspension was kept still at room temperature (21. + -. 1) ℃ for 24 hours.

(3) Preparation of soil pollution improver

Comparative example

A soil pollution improver is prepared by the following steps:

(1) preparation of sludge compost product

(2) Preparation of soil pollution improver

The prepared sludge compost product and clay powder are mixed according to the weight ratio of 5:2 and then are prepared into particles with the particle size of about 2 mm.

Examples of the experiments

Adopting farmland soil in laboratoryThe test is carried out, and the soil ratio of the conditioner is 10: 1 proportion of soil conditioner added in the examples and the comparison, and C of carbamazepine in the soil after 96 hours of treatment_t/C₀The values and the measurement results are shown in Table 1, and C of carbamazepine in the soil after 720min treatment under different ph conditions is measured_t/C₀The values and measurement results are shown in Table 2.

TABLE 1 Carbamazepine C in soil before and after application_t/C₀Value of

TABLE 2 Carbamazepine C in amendment soil applied under different ph conditions_t/C₀Value of

The invention can not only effectively remove the heavy metal pollution of the soil, but also degrade partial pollutants in the soil due to the activity of microorganisms in the sludge composted product after being applied for a period of time, simultaneously provide some nutrient elements required by the soil, improve the microbial environment of the soil, improve the soil fertilizer and finally promote the growth of crops.

It should be noted that the above examples are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the examples given, those skilled in the art can modify the technical solution of the present invention as needed or equivalent substitutions without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. The soil conditioner for removing carbamazepine is characterized by comprising urban sludge composted materials, clay powder and CMC-MnO₂Mixing the nano particles;

the municipal sludge composted material, clay powder and CMC-MnO₂The mass ratio of the nanoparticles is 4-6: 1-2: 1;

the urban sludge composted material is prepared by uniformly mixing and fermenting dewatered sludge, peanut shells and compost backmixing materials; the mass ratio of the dewatered sludge to the peanut shells to the compost return material is 2-4: 1: 1;

respectively preparing sodium carboxymethylcellulose solution and MnCl₂Blowing the solution by nitrogen; under nitrogen purge, MnCl is added₂Adding the solution into CMC solution to prepare the solution containing CMC-Mn²⁺A mixture of the complexes;

will contain KMnO₄Adding the stock solution of NaOH into the mixture drop by drop, and simultaneously carrying out oscillation treatment to obtain CMC-MnO₂Standing the nano-particle suspension, and separating to obtain CMC-MnO₂A nanoparticle;

the concentration of the sodium carboxymethyl cellulose solution is 10-60 mg/L;

the MnCl₂The concentration of the solution is 2-5 mM;

the KMnO₄The concentration of the solution is 2-5 mM;

the concentration of the NaOH solution is 4-10 mM;

the CMC-MnO₂The concentration of the nanoparticle suspension is 0.2-2 mM.

2. The soil amendment of claim 1, wherein the post-compost municipal sludge material, clay powder, and CMC-MnO₂The mass ratio of the nanoparticles was 5:2: 1.

3. The soil amendment of claim 1, wherein the mass ratio of dewatered sludge, peanut shells, and compost return material is 3:1: 1.

4. A soil amendment according to claim 1, wherein the soil amendment particles have a particle size of no more than 2 mm.

5. A process for the preparation of a soil amendment according to any of claims 1 to 4, characterised in thatThe preparation method comprises composting the municipal sludge, clay powder and CMC-MnO₂And (4) mixing the nano particles.

6. The method of claim 5, wherein the method of preparing the post-municipal sludge composting material comprises: uniformly mixing the dewatered sludge, the peanut shells and the compost return material, and fermenting;

the mass ratio of the dewatered sludge to the peanut shells to the compost return material is 2-4: 1: 1.

7. The method of claim 6, wherein the mass ratio of the dewatered sludge, peanut shells, and compost return material is 3:1: 1.

8. the method of claim 5, wherein the post-municipal sludge composting material fermentation process comprises: spraying water to the mixed materials, stirring to make the water content of the mixed materials be 55-60%, turning the piles every two to three days to ensure the oxygen content of the piles, spraying water every two weeks, uniformly turning and continuing to ferment; the fermentation is soft, non-sticky and gray black, and the preparation is successful.

9. The method according to claim 5, wherein the specific conditions of the shaking treatment are as follows: oscillating and reacting for 10-30 min under the condition of 200-300 rpm.

10. Use of a soil amendment as claimed in any one of claims 1 to 4 for the adsorptive degradation of soil carbamazepine.