阅读说明：本技术 一种纳米磁性层状双羟基氢氧化物吸附剂的制备及应用 (Preparation and application of nano magnetic layered double hydroxide adsorbent ) 是由 杨潇剑 安蒙蒙 韩南南 刘朱鹏 叶玉东 陈泳坤 王金星 李雅倩 于 2021-09-06 设计创作，主要内容包括：本发明公开一种纳米磁性层状双羟基氢氧化物吸附剂的制备及应用。该磁性层状双羟基氢氧化物吸附材料是采用超声辅助共沉淀的方法来进行合成的。首先利用铁盐来制备纳米级磁性铁氧体,再将其与CaO、AlCl-(3)的混合液在超声下进行充分反应,从而制备出一种纳米磁性层状双羟基氢氧化物吸附剂,吸附剂层板特征明显,负载的磁性颗粒均匀地分布在表面,并且其对阴离子典型有机污染物酸性品红的去除率达到90%,在外加磁场作用下能够较为容易的从污水中分离开来。(The invention discloses a preparation method and application of a nano magnetic layered double hydroxide adsorbent. The magnetic layered double hydroxide adsorbing material is synthesized by adopting an ultrasonic-assisted coprecipitation method. Firstly, iron salt is used to prepare nano-scale magnetic ferrite, and then the nano-scale magnetic ferrite is mixed with CaO and AlCl 3 The mixed solution is fully reacted under the ultrasound, thereby preparing the nano magnetic layered double hydroxide adsorbent with the laminated characteristicObviously, the loaded magnetic particles are uniformly distributed on the surface, the removal rate of the loaded magnetic particles to the typical organic pollutant acid fuchsin of anions reaches 90%, and the loaded magnetic particles can be easily separated from sewage under the action of an external magnetic field.)

1. The nano magnetic layered double hydroxide adsorbent is characterized in that a prepared layered double hydroxide adsorbent has obvious plate characteristics, magnetic particles uniformly loaded on the surface of the prepared layered double hydroxide adsorbent reach a nano level, the unit adsorption capacity of the nano magnetic layered double hydroxide adsorbent to organic dye magenta is larger, the adsorption efficiency of the nano magnetic layered double hydroxide adsorbent is higher, and the nano magnetic layered double hydroxide adsorbent can be easily separated from polluted water under the action of a magnetic field.

2. The preparation method of the nano-magnetic layered double hydroxide adsorbent according to claim 1 comprises the following steps: (1) preparing a material; (2) taking a certain amount of FeSO₄•7H₂O、Fe₂(SO₄)₃Pouring into a three-neck flask, and then adding 200 mL of deionized water; the deionized water used in the invention is fully aerated with nitrogen before use to remove dissolved oxygen in the water; (3) setting a certain temperature, adding magnetons, stirring in a stirrer, adding ammonia water for regulating pH while adding, measuring pH while stirring, aging after regulating pH, separating solid and liquid by using a magnet, pouring and recovering concentrated ammonia water, and repeatedly washing solid particles with deionized water until the pH value is neutral; (4) after washing, drying the solid particles in an oven, and grinding and bagging the dried substances in an agate mortar for later use; (5) then adding the prepared magnetic substance into CaO and AlCl₃Preparing magnetic Ca/Al-LDH in the mixed solution under the ultrasonic assistance.

3. The nano-magnetic layered dihydroxy hydrogen hydroxide according to claim 2The method for preparing the adsorbent is characterized in that the Fe added in the step (2)²⁺And Fe³⁺The ratio of the amount of the substances is 1:1, and the concentration is between 0.4mol/L and 0.65 mol/L.

4. The method for preparing the nano-magnetic layered double hydroxide adsorbent according to claim 2, wherein the aging time in the step (3) is 60min, and the ammonia concentration is 25-28%.

5. The method for preparing a nano-magnetic layered double hydroxide adsorbent according to claim 2, wherein in the step (5), calcium oxide (CaO) is firstly poured into a conical flask, deionized water is added into the conical flask, ultrasonic treatment is carried out for 15min in ultrasonic waves, and then aluminum trichloride (AlCl) is sequentially and respectively added₃) And magnetic nano ferrite, and then continuing to perform ultrasonic treatment in the ultrasonic wave for 120 min.

6. The nano-magnetic layered double hydroxide adsorbent based on claim 1 is used for removing anionic organic pollutants in an environmental water sample.

Technical Field

The invention relates to the technical field of preparation and application of a layered double hydroxide negative magnetic adsorbent, in particular to preparation and application of a nano magnetic layered double hydroxide adsorbent.

Background

In the current social production process, the produced wastewater is continuously increased along with the progress of the times. Wherein the waste water produced in the textile, printing and dyeing and paper making industries contains a large amount of anionic dye. The dye wastewater has the characteristics of complex components, high chromaticity, poor biodegradability, high chemical stability and the like, so that the removal of organic pollutants in the dye wastewater becomes a worldwide problem. The common treatment methods of the dye wastewater include a flocculation precipitation method, a chemical oxidation method, an advanced oxidation method, a biological method, an adsorption method and the like. These treatments, while each having unique advantages, have limited application due in large part to high cost, complexity of operation and difficulty in solid-liquid separation. The adsorption method has the advantages of simple and convenient experimental operation, high removal rate of anionic dye in water and the like, so that the adsorption method is widely applied.

Layered Double Hydroxides (LDHs) consist of positively charged layers and negatively charged anions filled between the layers. The chemical formula of the LDH material is mainly [ M_1-x ²⁺M_x ³⁺(OH)₂]^x+A_x/n ^n- mH₂O, wherein M²⁺Refers to divalent metal cations, e.g. Mg²⁺、Ca²⁺、Zn²⁺。M³⁺Refers to a trivalent metal cation, e.g. Al³⁺、Co³⁺、Fe³⁺。A^n-For the purpose of stabilizing the presence of anions in alkaline solutions, mainly between layers, e.g. Cl^-、NO^3-、OH^-、CO₃ ^2-、SO₄ ^2-Plasma complexing ions or organic ions and inorganic anions. The value of x is in the range of 0.20 to 0.33 and represents the mole fraction of the metal ion M3+, and M is the number of water molecules in the interlayer structure. The layered double hydroxide consists of mainly interlayer anionic component, interlayer cationic component, its charge density and M²⁺/M³⁺The molar ratio is determined jointly. Based on the special layered structure of LDH, its most important characteristics are: memory effect, controllability of layered cations, exchangeability of interlayer anions and their basicity. q wherein the exchangeability of the interlayer anions is its main property. Various anions in the solution are introduced into the interlayer by the ion exchange principle, so that the interlayer anions are released, and a corresponding intercalated LDH material can be obtained, thereby achieving the purpose of removing anion pollutants in the water body.

In recent years, partial research focuses on the development and application of magnetic adsorbents, namely, magnetic substances are loaded on adsorption materials to enable the adsorbents to show corresponding magnetism, so that a magnetic separation technology is applied to separation and recovery of saturated adsorbents in liquid-phase pollutants after adsorption is completed, long-time filtration or centrifugal operation is omitted, and the magnetic adsorbent has the advantages of high treatment and separation speed, high efficiency, simplicity and convenience in equipment operation, low construction and maintenance cost and the like. The commonly used magnetic substances are metallic simple substances, alloys or compounds such as Fe, Ni, Pd and the like, wherein the magnetic ferrite is the most simple and easily obtained and stable paramagnetic material.

CN113070038A discloses a magnetic nano material for removing azole bactericides in an environmental water sample, and Fe is firstly required to be removed₃O₄、Zn(NO₃)₂·6H₂O and Al (NO)₃)₃·9H₂And adding O into water according to a certain proportion, adjusting the pH value of the solution, stirring for a period of time, centrifuging, washing the product with methanol or absolute ethyl alcohol, and drying in vacuum to obtain the magnetic double-layer hydroxide. However, the observation of the result of a scanning electron microscope shows that the formed product is of a core-shell structure, the layered double hydroxide is of a shell, and the magnetism is Fe₃O₄Is the core of the product, and has a size of 1-2 μmOn the nanometer level, the removal rate of the triazolone and the epoxiconazole is only about 5 percent and 70 percent respectively.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the prepared layered double hydroxide adsorbent has obvious layered characteristics, magnetic particles uniformly loaded on the surface of the layered double hydroxide adsorbent reach a nanometer level, the unit adsorption capacity of the layered double hydroxide adsorbent to organic dye magenta is larger, the adsorption efficiency is higher, and the layered double hydroxide adsorbent can be easily separated from polluted water under the action of a magnetic field.

The present invention adopts the following technical means to achieve the above object.

1. The preparation method of the nano magnetic layered double hydroxide adsorbent comprises the following steps: (1) the material is prepared. (2) Taking a certain amount of FeSO₄•7H₂O、Fe₂(SO₄)₃Poured into a three-necked flask, and added 200 mL of deionized water. The deionized water used in the invention is fully aerated with nitrogen before use to remove dissolved oxygen in the water; (3) setting a certain temperature, adding magnetons, stirring in a stirrer, adding ammonia water for regulating pH while adding, measuring pH while stirring, aging after regulating pH, separating solid and liquid by using a magnet, pouring and recovering concentrated ammonia water, and repeatedly washing solid particles with deionized water until the pH value is neutral; (4) and after washing, drying the solid particles in an oven, and grinding and bagging the dried substances in an agate mortar for later use. (5) Then adding the prepared magnetic substance into CaO and AlCl₃Preparing magnetic Ca/Al-LDH in the mixed solution under the ultrasonic assistance.

Fe added in the step (2)²⁺And Fe³⁺The mass ratio of the materials is 1:1, Fe²⁺And Fe³⁺The concentration of (b) is between 0.4mol/L and 0.65 mol/L.

The deionized water is preferably exposed to nitrogen for more than 15min in the step (2).

Setting the temperature at 45 ℃ in the step (3), adding magnetons, stirring in a stirrer for 15min, and adding a precipitator ammonia water to adjust the pH to be about 11. And then aged.

And (4) aging for 60min in the step (3), adding deionized water for washing, and adjusting the pH value to be about 7.

The concentration of the ammonia water in the step (3) is 25-28%.

In the step (4), the temperature of the oven needs to be kept at 50-70 ℃, and the drying time is 5-8 h.

2. The nano magnetic layered double hydroxide adsorbent is applied to purification of magenta dye wastewater: 0.5g of prepared high-purity magnetic layered double hydroxide adsorbing material is added into 50mL of acid fuchsin solution with the concentration of 100mg/L, the acid fuchsin solution is placed into a constant-temperature water bath oscillator to be continuously oscillated for 60min, the adsorption effect is optimal, and finally, under the action of a magnetic field, the treated acid fuchsin solution and solid particles are easy to separate.

The invention has the beneficial effects that: the layered double hydroxide adsorbent in the nano magnetic layered double hydroxide adsorbent prepared by the method has obvious layered characteristics, magnetic particles uniformly loaded on the surface of the layered double hydroxide adsorbent reach a nano level, the unit adsorption capacity of the layered double hydroxide adsorbent to the organic dye fuchsin is larger, the adsorption efficiency is higher, and the layered double hydroxide adsorbent can be easily separated from a polluted water body under the action of a magnetic field.

Drawings

FIG. 1 is a scanning electron microscope image of the nano-magnetic layered double hydroxide adsorbent prepared by the present invention.

FIG. 2 is a scanning electron microscope image of the layered double hydroxide adsorbent prepared by the present invention.

FIG. 3 is an SEM-EDS element distribution image of the nano-magnetic layered double hydroxide adsorbent prepared by the invention.

FIG. 4 is an SEM-EDS elemental distribution image of the layered double hydroxide adsorbent prepared according to the present invention.

Fig. 5 shows the effect of the nano-magnetic layered double hydroxide adsorbent prepared by the present invention on the adsorption amount of acid fuchsin under different treatment times.

FIG. 6 shows the effect of the nano-magnetic layered double hydroxide adsorbent prepared by the present invention on the adsorption amount of acid fuchsin at different dosage amounts.

Fig. 7 shows the effect of the nano-magnetic layered double hydroxide adsorbent prepared by the invention on the adsorption amount of acid fuchsin under different pH values.

Detailed Description

The invention relates to a preparation and application of a high-purity magnetic layered double-hydroxide adsorbing material, which comprises the following steps: firstly weighing 5.56 g of ferrous sulfate and 8.00g of ferric sulfate by using an analytical balance, pouring the ferrous sulfate and the ferric sulfate into a three-neck flask, then adding 200 mL of deionized water, adding magnetons into the flask, stirring the mixture in a stirrer for 15min at the temperature of 45 ℃, adding a precipitator ammonia water into the mixture to adjust the pH value to be about 11, then aging the mixture for 60min, pouring the prepared magnetic substance into a beaker, repeatedly washing the magnetic substance to be neutral by using the deionized water, drying the magnetic substance in a drying box at the temperature of 60 ℃, grinding the dried substance by using an agate mortar and bagging the ground substance for later use.

The magnetic layered double hydroxide adsorbing material is synthesized by adopting a coprecipitation method, and the synthesis process is as follows: firstly, 0.5604 g of calcium oxide (CaO) weighed by an analytical balance is poured into a conical flask, 50mL of deionized water is added, ultrasonic treatment is carried out in ultrasonic waves for 15min, and then 0.8177 g of aluminum trichloride (AlCl) are sequentially and respectively added₃) 0.3495 g of newly prepared magnetic substance is continuously subjected to ultrasonic treatment in ultrasonic waves for 120 min, and is aged for 60min under the condition of constant-temperature water bath at 45 ℃, then the supernatant is poured off, and is finally dried in a drying oven at 60 ℃, and the dried substance is ground by an agate mortar and is bagged for later use.

Corresponding characterization tests were performed on the magnetic nanomaterials prepared in the examples, as follows.

(1) Fig. 1 and fig. 2 show that the prepared layered double hydroxide adsorbent has obvious plate characteristics, and the loaded magnetic particles are uniformly distributed on the surface of the LDH and reach the nanometer level.

(2) The SEM-EDS scan results of fig. 3 and 4 indicate that the Fe element has been uniformly supported on the surface of the LDH after the negative magnetic treatment.

The results of the single-factor experiments in fig. 5, 6 and 7 show that the adsorption of the magnetic layered dihydroxy hydroxide to acid fuchsin is optimal and the removal rate reaches about 90% under the conditions of pH 5, the addition amount of 0.5g and the time of 60 min.

Finally, it should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned embodiments, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.