CN110052241A - A kind of preparation and application of cubic spinel type Mn/Al oxysome sludge organism Carbon Materials - Google Patents

Abstract

The invention belongs to the field of environmental functional materials and biomass resource utilization, and particularly relates to a one-step hydrothermal method for preparing cubic spinel-type Mn/Al oxygen body-sludge biochar material and its application. The preparation method includes the following steps: (1) adding the sludge to deionized water to make it evenly dispersed in the solution. (2) The manganese chloride and aluminum chloride are then dissolved into the solution containing the sludge powder and continuously stirred. During the stirring process, NaOH is added dropwise to the mixed solution. (3) Subsequently, the mixed solution was moved to a stainless steel hydrothermal reactor for reaction. (4) After the reaction is finished and naturally cooled, the filtered precipitate is washed with deionized water until neutral, and dried. The method has the advantages of simple process, stable source and low cost for preparing raw materials, and also provides a new way for the resource utilization of sludge, and provides a new phosphorus adsorbent, which has good environmental effect and social effect.

Description

Preparation and application of a cubic spinel-type Mn/Al oxygen body sludge biochar material

technical field

The invention belongs to the field of environmental functional materials and biomass resource utilization, and in particular relates to a cubic spinel type Mn/Al oxygen body-sludge biochar material and a preparation method and application thereof.

Background technique

With the development of urbanization and the unprecedented growth of the population, the discharge of a large amount of phosphorus-containing wastewater has made the eutrophication of water bodies increasingly serious, resulting in an imbalance in the distribution of species in the aquatic ecosystem, causing algal blooms and fish deaths. Therefore, there is an urgent need to develop an efficient and environmentally friendly method to remove phosphorus from water bodies.

In recent years, as a new type of biomass adsorption material, biochar has attracted the attention of researchers at home and abroad. Biochar is a porous carbon-containing material prepared by anoxic pyrolysis carbonization of biomass raw materials. Its morphological structure is relatively stable and carbon-rich. So far, the biomass raw materials commonly used in the preparation of biochar mainly include a variety of crop wastes and by-products, waste wood, manure and municipal sludge. However, the low yield of waste wood and the seasonality of crop waste will limit the preparation and large-scale promotion of biochar to a certain extent. In comparison, selecting municipal sludge as raw material to prepare sludge-based biochar has the advantages of stable source and low cost, and also provides a new way for the resource utilization of sludge, which has good environmental effects and social benefits. effect. Generally, biochar can show good adsorption performance for cations, but the adsorption effect for anions such as NO ₃ ^- and PO ₄ ^3- is not ideal. This is due to the fact that the surface of biochar is usually negatively charged, which limits its adsorption capacity. Adsorption attraction of negatively charged ions. In order to improve the adsorption capacity of biochar to phosphate, metal elements are usually added to the biochar to increase the zero net charge point of the biochar. The cubic spinel-type Mn/Al oxobody is composed of Mn ²⁺ and Al ³⁺ occupying tetrahedral and octahedral cation sites, respectively, and has a high zero net charge point. At present, the cubic spinel-type oxygen body and its derivative composites have been used for adsorption and removal of various pollutants, such as heavy metals, antibiotics and dyes, due to their high stability and large specific surface area. There are few reports on the adsorption of phosphorus in water. The invention uses sewage sludge as raw material, composites AlCl ₃ and MnCl ₂ hydrothermal carbon to synthesize cubic spinel type Mn/Al oxygen body-sludge biochar (MA-BC), and investigates its adsorption performance and mechanism to phosphorus. , which provides a new way to improve the preparation of biochar by adsorption and removal of phosphate in water, and realizes the resource utilization of sludge.

SUMMARY OF THE INVENTION

In view of the above-mentioned existing problems and technical analysis, an object of the present invention is to provide a preparation method of cubic spinel type Mn/Al oxygen body-sludge biochar material (MA-BC), which is simple to operate and easy to obtain raw materials , the prepared MA-BCs have larger specific surface area and total pore volume. Another object of the present invention is to provide the application of MA-BC, which not only realizes the resource utilization of sludge, but also provides a new phosphorus adsorbent.

For realizing above-mentioned first purpose, the present invention has adopted following technical scheme:

A method for preparing a cubic spinel-type Mn/Al oxygen body-sludge biochar material, comprising the following steps:

(1) Add 2.5 g of powdered sludge to 50 mL of deionized water and stir for 1 h to make it evenly dispersed in the solution.

(2) Add 0.01 mol of manganese chloride tetrahydrate (MnCl ₂ ·4H ₂ O) and 0.02 mol of aluminum chloride hexahydrate (AlCl ₃ ·6H ₂ O) to the solution described in step (1), and continue with a magnetic stirrer Stir for 30 min.

(3) 5 M NaOH is added dropwise to the solution in step (2) until the pH of the solution is greater than or equal to 10.

(4) Transfer the solution described in step (3) to a 100 ml PTFE-lined stainless steel hydrothermal reactor, and react at 453 K for 12 h.

(5) After the reaction described in step (4) is completed, the obtained precipitate is washed with deionized water until neutral, and finally dried at 333 K for 24 h, the obtained sample is cubic spinel type Mn/Al oxygen Body Sludge Biochar (MA-BC).

For realizing the above-mentioned another purpose, the present invention has adopted the following technical scheme:

An application of the prepared cubic spinel-type Mn/Al oxygen body sludge biochar as a phosphorus adsorbent for efficiently adsorbing phosphorus.

The beneficial effects of the invention are as follows: using a simple one-step hydrothermal method, using municipal sludge as a raw material, and compounding AlCl ₃ and MnCl ₂ to synthesize MA-BC, the material has the advantages of good chemical stability and large specific surface area. The method has the advantages of simple process, stable source and low cost for preparing raw materials, and also provides a new way for the resource utilization of sludge, and has good environmental effect and social effect.

Description of drawings:

FIG. 1 is a field emission scanning electron microscope (FESEM) image of the MA-BC adsorption material of the present invention.

Fig. 2 is the XRD pattern of the MA-BC adsorption material of the present invention.

3 is a graph showing the influence of the MA-BC adsorption material of the present invention on the adsorption effect of phosphorus under different pH conditions.

Fig. 4 is a kinetic study diagram of the adsorption and removal of phosphorus by the MA-BC adsorbent of the present invention.

FIG. 5 is a graph showing the adsorption effect of the MA-BC adsorption material of the present invention on phosphorus with different concentrations.

Detailed ways:

The present invention will be described in detail below in conjunction with the examples, so that those skilled in the art can better understand the present invention, but the present invention is not limited to the following examples.

Example 1:

Preparation of cubic spinel-type Mn/Al oxygen body-sludge biochar: First, the dewatered sludge was dried at 105 °C to constant weight, and ground through a 200-mesh sieve. Then 2.5 g of powdered sludge was added to 50 mL of deionized water and stirred for 1 h to make it evenly dispersed in the solution, and then 0.01 mol of manganese chloride tetrahydrate (MnCl ₂ ·4H ₂ O) and 0.02 mol of chlorine hexahydrate were added. Aluminium (AlCl ₃ ·6H ₂ O) was dissolved into the solution containing the sludge powder and stirred continuously for 30 min with a magnetic stirrer. During the stirring process, 5 M NaOH was added dropwise to the mixed solution until the pH was greater than or equal to 10. Subsequently, the mixed solution was transferred to a 100 ml PTFE-lined stainless steel hydrothermal reactor and reacted at 453 K for 12 h. After the reaction was finished and cooled naturally, the filtered precipitate was washed with deionized water until neutral, and finally dried at 333 K for 24 h. The obtained sample was the cubic spinel-type Mn/Al oxide biochar (MA-BC ).

The SEM analysis results of the MA-BC adsorbent (Fig. 1) showed that the surface of the MA-BC was irregular and porous, with densely grown sheet-like substances. The XRD analysis results of MA-BC are shown in Figure 2. There are diffraction peaks at 2θ of 30.09°, 36.56°, 42.68°, 56.56°, and 63.04°, which correspond to (220) and (222) in the cubic spinel structure, respectively. The main characteristic peaks of , (400), (333) and (440) crystal planes, indicating that the cubic spinel-type Mn/Al oxygen bodies were successfully grown on the surface of sludge biomass.

Example 2:

The effect of different pH values on the adsorption and removal of phosphorus by MA-BC in Example 1: Weigh 0.1 g of MA-BC into a conical flask containing 100 mL of a phosphate solution with a concentration of 50 mg/L, and add 0.1 M HCl and The pH of the solution was adjusted to 2-10 with NaOH, and the interval was 1, and then the conical flask was placed in a constant temperature shaker with a temperature of 298 K for 24 h. After the adsorption was completed, the supernatant was taken, filtered with a 0.45 μm membrane, and the phosphate concentration was detected with a UV-vis spectrophotometer. The results are shown in Fig. 3, when the pH is equal to 3, the adsorption capacity is the largest, which is 28.2 mg/g. When the pH was equal to 2, the adsorption amount was the smallest, about 0.2 mg/g. When the pH was greater than 3, the adsorption amount showed a decreasing trend with the increase of pH.

Example 3:

The kinetic study of the MA-BC prepared in Example 1 for adsorption and removal of phosphorus: Weigh 0.1 g of MA-BC into a conical flask containing 100 mL of a phosphate solution with a concentration of 50 mg/L, adjust The pH of the solution was 3, and then the conical flask was placed in a constant temperature shaker with a temperature of 298 K for 48 h, and the flask was shaken for 48 h at different time periods (1 min, 5 min, 10 min, 30 min, 1 h, 2 h, 5 h, 12 h, 24 h, 36 h, 48 h) Take the supernatant, filter it with a 0.45 μm membrane, and use a UV-vis spectrophotometer to detect the phosphate concentration. The results are shown in Fig. 4. The adsorption rate was faster before 10 min, then began to decrease, and finally reached equilibrium at about 36 h, and the adsorption amount at equilibrium was 31.2 mg/g.

Example 4:

The MA-BC prepared in Example 1 was used for the adsorption of solutions with different phosphorus concentrations: 0.1 g MA-BC was added to a solution containing 100 mL of the specified phosphate concentration (20 mg/L, 50 mg/L, 80 mg /L, 150 mg/L, 200 mg/L, 300 mg/L), adjust the pH of the solution to 3, and then place the conical flask in a constant temperature shaker with a temperature of 298 K for 24 h. After the adsorption was completed, the supernatant was taken, filtered with a 0.45 μm membrane, and the phosphate concentration was detected with a UV-vis spectrophotometer. The results are shown in Figure 5. With the increase of the initial concentration of phosphate, the equilibrium adsorption capacity of MA-BC showed a trend of first increasing and then flattening, and the maximum adsorption capacity was 58.77 mg/g.

Claims (2)

1. a kind of preparation method of cubic spinel type Mn/Al oxysome sludge organism Carbon Materials, which is characterized in that including following step It is rapid: (1) the powdered sludge of 2.5 g to be added in 50 mL deionized waters and stirring 1 h keeps its evenly dispersed in the solution； (2) 0.01 mol, tetra- chloride hydrate manganese (MnCl is added into step (1) described solution₂·4H₂O) and 0.02 mol six is hydrated chlorine Change aluminium (AlCl₃·6H₂O 30 min), and with magnetic stirring apparatus are persistently stirred；(3) 5 are added dropwise into step (2) described solution M NaOH, until pH value of solution is more than or equal to 10；(4) step (3) described solution is moved to the polytetrafluoroethyllining lining of 100 ml In stainless steel hydrothermal reaction kettle, 12 h are reacted at 453 K；(5) heavy to what is after reaction, obtained described in step (4) Shallow lake is cleaned with deionized water to neutrality, 24 h is finally dried at 333 K, gained sample is cubic spinel type Mn/Al oxygen Body sludge organism charcoal (MA-BC).

2. the application of cubic spinel type Mn/Al oxysome sludge organism charcoal prepared by a kind of claim 1, it is characterised in that: Efficient absorption phosphorus is used for as phosphorus adsorbent.