CN1260002C - Process for preparing porous clay isomeric material - Google Patents

Abstract

The invention discloses a preparation method of a porous clay material. The process of the method is: firstly, the waste organic bentonite after dehydration and drying is mixed and reacted with the co-surfactant; then the neutral inorganic precursor is added to carry out the stirring reaction; then the solid-liquid separation; the solid part is roasted to remove the surfactant and the adsorbed organic matter Dyes, that is, get the required porous clay heterogeneous material. The step of reacting cationic surfactant and clay in the conventional synthesis method is unnecessary, and no additional cationic surfactant needs to be added. The porous clay heterogeneous material prepared by the method conforms to the characteristics of similar materials prepared by conventional methods, and has large specific surface area, uniform pore distribution, pore diameter between micropores and mesopores, and high void order. Since the material uses extremely low-cost waste as a raw material and does not need to add cationic surfactants, the synthesis cost is greatly reduced and the preparation steps are simplified.

Description

A kind of preparation method of porous clay heterogeneous material

Technical field

The invention belongs to the technical field of inorganic porous materials, and in particular relates to a method for preparing porous clay heterogeneous materials, in particular to a method for preparing porous clay materials by using organobentonite treated with organic wastewater as the main clay raw material and providing cationic surfactants.

Background technique

Mesoporous materials represented by MCM-41, MCM48, FSM-16 and HMS are one of the research hotspots in the fields of chemistry, physics, materials and environmental protection in the world in recent years. In 1995, Galameau et al. (Nature, 1995, 374(6):529~531) firstly reported a class of mesoporous materials with good thermal stability and pore sizes ranging from ultra-large micropores to mesopores (1.4-2.2nm), namely porous clay heterogeneous materials (PCHs) . Like other mesoporous materials, this kind of material has the advantages of large pore size, uniform and adjustable pore size, high degree of void order, large specific surface area, etc., and also has better mechanical stability and hydrothermal stability. The synthesis of porous clay materials is different from the synthesis of conventional mesoporous materials, which uses the supramolecular structure formed by surfactants as a template, uses sol-gel chemical processes, and assembles through the interface orientation between organic matter and inorganic matter. Instead, organic cations and neutral amines that enter the interlayer pores act as co-surfactant templates to guide neutral inorganic precursors to perform interlayer hydrolysis and condensation polymerization in the interlayer pores of 2:1 layered clay minerals, and then undergo Roasting removes the surfactant, and finally a porous clay material is obtained. The main preparation steps are:

1) Cationic surfactants react with layered clay minerals to form organoclay complexes;

2) The organoclay complex reacts with a co-surfactant;

3) React with neutral inorganic precursors;

4) Roasting to remove the surfactant.

At present, the research on this material mainly focuses on synthesis conditions (ratio of raw materials, types and ratios of surfactants and co-surfactants, reaction conditions, calcination temperature, etc.), structural characterization, adsorption performance, catalytic performance and so on. However, larger-scale synthesis and application must also address issues such as optimization of synthesis process conditions, raw material sources and costs. The practical application of porous clay heterogeneous materials will be well promoted if the host clay raw materials and surfactants that are cheaper and more widely sourced can be used as raw materials.

Bentonite is a typical 2:1 layered clay mineral composed of montmorillonite as the main mineral. The organic bentonite formed after organic modification with surfactants has an adsorption efficiency of organic matter that is tens to hundreds of times higher than that of the original soil. , due to its excellent adsorption properties to organic matter, organic bentonite has become a research hotspot in the field of environmental science and engineering in the application of waste water (especially organic waste water) treatment and polluted environment remediation. However, the lack of cost-effective regeneration and disposal methods is still one of the main problems restricting the practical application of organobentonite in wastewater treatment. If organic bentonite adsorbed with organic pollutants can be used comprehensively, it will not only reduce the cost of wastewater treatment, but also avoid secondary pollution caused by waste adsorbents.

Contents of the invention

The purpose of the present invention is to provide a method for synthesizing porous clay heterogeneous materials.

The organic bentonite after adsorbing and treating organic wastewater is used as the main clay raw material for synthesis, and a co-surfactant is added as a template-directing agent to guide the interlayer hydrolysis and condensation polymerization of the neutral inorganic precursor in the interlayer pores of bentonite to form an inorganic-organic clay. Composite intermediates; organic-inorganic composite intermediates are roasted to remove surfactants to obtain porous clay heterogeneous materials.

The specific preparation steps of the porous clay heterogeneous material are as follows:

1) The organic bentonite after adsorption treatment of organic wastewater is separated from solid and liquid, dried in the air, and then dried at 50-100°C for 12-24 hours to remove adsorbed moisture;

2) Mixing the dried organobentonite and co-surfactant according to the mass ratio of organobentonite: co-surfactant = 1:0.5～1:2, stirring and reacting at 20～80°C for 15～60min;

3) At room temperature, according to organic bentonite: neutral inorganic precursor (mass ratio) = 1: 100 ~ 1: 200, slowly drop in the neutral inorganic precursor, and stir for 2 ~ 8 hours;

4) solid-liquid separation without washing, and the solid part is air-dried at room temperature to obtain an inorganic-organic composite intermediate;

5) Under an air atmosphere, heat up to 500-750°C at a rate of 2-5°C/min, and roast for 5-10 hours to remove surfactants and adsorbed organic pollutants.

The co-surfactant in the above method can be one of the neutral amines whose chemical formula is _C nH _n-1 NH ₂ (n is the number of carbon atoms, and n ranges from 6 to 18), and the neutral inorganic precursor is methyl orthosilicate One of ester, ethyl orthosilicate, propyl orthosilicate, and butyl orthosilicate. Organobentonite is an organoclay obtained by reacting a kind of quaternary ammonium salt type or alkylpyridine type cationic surfactant with bentonite.

The porous clay heterogeneous material prepared by the invention has a specific surface area of 400-900m ² /g, a pore volume of 0.1-0.5cm ³ /g, an average pore diameter of 13-30nm, a thermal stability temperature of at least 750°C, and a benzene saturated adsorption capacity of 0.2- 0.7g/g (at 25°C, the relative pressure of benzene at adsorption equilibrium is 0.5), and the saturated adsorption capacity of carbon tetrachloride is 0.3-0.8g/g (at 25°C, the relative pressure of carbon tetrachloride at adsorption equilibrium is 0.5). The porous clay heterogeneous material prepared by the invention is particularly suitable for the adsorption and separation of volatile organic compounds (VOCs).

The advantages of the present invention are:

1) Using waste organic bentonite from a wide range of sources and extremely cheap as a raw material, without additional cationic surfactants, reduces the cost of preparing raw materials;

2) The preparation steps are simplified, and the synthesis process of the organoclay composite is omitted;

3) The comprehensive utilization of organic bentonite in wastewater treatment can make full use of bentonite resources, reduce the cost of wastewater treatment, and avoid secondary pollution, thereby promoting the application of organic bentonite in wastewater treatment.

Detailed ways

The present invention will be further elaborated below by embodiment:

Embodiment 1, the organic bentonite (being called for short CTMAB bentonite) prepared by the ratio of 0.1mol cetyltrimethylammonium bromide/100g bentonite is at first used for adsorption treatment to contain the waste water of 1000mg/L p-nitrophenol (PNP), The saturated adsorption capacity of CTMAB bentonite is 96mgPNP/g, solid-liquid separation, CTMAB bentonite (PNP-CTMAB bentonite) after absorbing p-nitrophenol is dried in the air, and then dried at 80°C for 24h in an air atmosphere. Mix 14g of DNP-CTMAB bentonite with 13g of dodecylamine, stir and react at 50°C for 30min, slowly add 120ml of ethyl orthosilicate dropwise, and stir at room temperature for 4h after the dropwise addition. Separation of solid and liquid, drying of the solid part, and finally heating up to 560°C at a rate of 3°C/min in an air atmosphere, and roasting for 6h to remove surfactants and adsorbed organic pollutants to obtain porous clay heterogeneous materials.

The main property indicators of the sample: the specific surface area is 660m ² /g, the pore volume is 0.25cm ³ /g, the average pore diameter is 24nm, the thermal stability temperature is at least 750°C, and the benzene saturated adsorption capacity is 0.35g/g (at 25°C, when the adsorption equilibrium The relative pressure of benzene is 0.5), and the saturated adsorption capacity of carbon tetrachloride is 0.50g/g (at 25°C, the relative pressure of carbon tetrachloride at adsorption equilibrium is 0.5).

Embodiment 2, the organobentonite (being called for short CPC bentonite) prepared by the ratio of 0.1mol cetylpyridinium chloride/100g bentonite is at first used for adsorption treatment to contain the waste water of 1000mg/L p-nitrophenol (PNP), the CPC bentonite The saturated adsorption capacity is 94mgPNP/g, solid-liquid separation, and the CPC bentonite (PNP-CPC bentonite) after absorbing p-nitrophenol is dried in the air, and then dried at 80°C for 24h in an air atmosphere. Mix 14g of DNP-CPC bentonite with 13g of dodecylamine, stir and react at 50°C for 30min, slowly add 120ml of ethyl orthosilicate dropwise, and stir at room temperature for 4h after the dropwise addition. Separation of solid and liquid, drying of the solid part, and finally heating up to 560°C at a rate of 3°C/min in an air atmosphere, and roasting for 6h to remove surfactants and adsorbed organic pollutants to obtain porous clay heterogeneous materials.

The main property indicators of the sample: the specific surface area is 550m ² /g, the pore volume is 0.23cm ³ /g, the average pore diameter is 22nm, the thermal stability temperature is at least 750°C, and the benzene saturated adsorption capacity is 0.25g/g (at 25°C, when the adsorption equilibrium The relative pressure of benzene is 0.5), and the saturated adsorption capacity of carbon tetrachloride is 0.45g/g (at 25°C, the relative pressure of carbon tetrachloride at adsorption equilibrium is 0.5).

Embodiment 3, the organobentonite (being called for short CTMAB bentonite) prepared by the ratio of 0.1mol cetyltrimethylammonium bromide/100g bentonite is at first used for adsorption treatment to contain the waste water of 1000mg/L p-nitrophenol (PNP), The saturated adsorption capacity of CTMAB bentonite is 96mgPNP/g, solid-liquid separation, CTMAB bentonite (PNP-CTMAB bentonite) after absorbing p-nitrophenol is dried in the air, and then dried at 80°C for 24h in an air atmosphere. Mix 14g of DNP-CTMAB bentonite with 28g of dodecylamine, stir and react at 50°C for 30min, slowly add 120ml of ethyl orthosilicate dropwise, and stir at room temperature for 4h after the addition is complete. Separation of solid and liquid, drying of the solid part, and finally heating up to 560°C at a rate of 3°C/min in an air atmosphere, and roasting for 6h to remove surfactants and adsorbed organic pollutants to obtain porous clay heterogeneous materials.

The main property indicators of the sample: the specific surface area is 680m ² /g, the pore volume is 0.26cm ³ /g, the average pore diameter is 24nm, the thermal stability temperature is at least 750°C, and the benzene saturated adsorption capacity is 0.42g/g (at 25°C, when the adsorption equilibrium The relative pressure of benzene is 0.5), and the saturated adsorption capacity of carbon tetrachloride is 0.55g/g (at 25°C, the relative pressure of carbon tetrachloride at adsorption equilibrium is 0.5).

Embodiment 4, the organobentonite (being called for short CTMAB bentonite) prepared by the ratio of 0.1mol cetyltrimethylammonium bromide/100g bentonite is at first used for adsorption treatment to contain the waste water of 1000mg/L p-nitrophenol (PNP), The saturated adsorption capacity of CTMAB bentonite is 96mgPNP/g, solid-liquid separation, CTMAB bentonite (PNP-CTMAB bentonite) after absorbing p-nitrophenol is dried in the air, and then dried at 80°C for 24h in an air atmosphere. Mix 14g of DNP-CTMAB bentonite with 13g of dodecylamine, stir and react at 50°C for 30min, slowly add 200ml of tetraethyl orthosilicate dropwise, and stir at room temperature for 4h after the dropwise addition. Separation of solid and liquid, drying of the solid part, and finally heating up to 560°C at a rate of 3°C/min in an air atmosphere, and roasting for 6h to remove surfactants and adsorbed organic pollutants to obtain porous clay heterogeneous materials.

The main property indicators of the sample: the specific surface area is 680m ² /g, the pore volume is 0.28cm ³ /g, the average pore diameter is 24nm, the thermal stability temperature is at least 750°C, and the saturated adsorption capacity of benzene is 0.46g/g (at 25°C, when the adsorption equilibrium The relative pressure of benzene is 0.5), and the saturated adsorption capacity of carbon tetrachloride is 0.62g/g (at 25°C, the relative pressure of carbon tetrachloride at adsorption equilibrium is 0.5).

Embodiment 5, the organobentonite (being called for short CTMAB bentonite) prepared by the ratio of 0.1mol cetyltrimethylammonium bromide/100g bentonite is at first used for adsorption treatment to contain the waste water of 1000mg/L p-nitrophenol (PNP), The saturated adsorption capacity of CTMAB bentonite is 96mgPNP/g, solid-liquid separation, CTMAB bentonite (PNP-CTMAB bentonite) after absorbing p-nitrophenol is dried in the air, and then dried at 80°C for 24h in an air atmosphere. Mix 14g of DNP-CTMAB bentonite with 13g of n-hexylamine, stir and react at 50°C for 30min, slowly add 120ml of ethyl orthosilicate dropwise, and stir at room temperature for 4h after the addition is complete. Separation of solid and liquid, drying of the solid part, and finally heating up to 560°C at a rate of 3°C/min in an air atmosphere, and roasting for 6h to remove surfactants and adsorbed organic pollutants to obtain porous clay heterogeneous materials.

The main property indicators of the sample: the specific surface area is 510m ² /g, the pore volume is 0.19cm ³ /g, the average pore diameter is 21nm, the thermal stability temperature is at least 750°C, and the benzene saturated adsorption capacity is 0.31g/g (at 25°C, when the adsorption equilibrium The relative pressure of benzene is 0.5), and the saturated adsorption capacity of carbon tetrachloride is 0.39g/g (at 25°C, the relative pressure of carbon tetrachloride at adsorption equilibrium is 0.5).

Embodiment 6, the organic bentonite (being called for short CTMAB bentonite) prepared by the ratio of 0.1mol cetyltrimethylammonium bromide/100g bentonite is at first used for adsorption treatment to contain the waste water of 1000mg/L p-nitrophenol (PNP), The saturated adsorption capacity of CTMAB bentonite is 96mgPNP/g, solid-liquid separation, CTMAB bentonite (PNP-CTMAB bentonite) after absorbing p-nitrophenol is dried in the air, and then dried at 80°C for 24h in an air atmosphere. Mix 14g of DNP-CTMAB bentonite with 13g of dodecylamine, stir and react at 50°C for 30min, slowly add 120ml of ethyl orthosilicate dropwise, and stir at room temperature for 4h after the dropwise addition. Separation of solid and liquid, drying of the solid part, and finally heating up to 700°C at a rate of 3°C/min in an air atmosphere, and roasting for 6 hours to remove surfactants and adsorbed organic pollutants to obtain porous clay heterogeneous materials.

The main property indicators of the sample: the specific surface area is 600m ² /g, the pore volume is 0.24cm ³ /g, the average pore diameter is 23nm, the thermal stability temperature is at least 750°C, and the benzene saturated adsorption capacity is 0.33g/g (at 25°C, when the adsorption equilibrium The relative pressure of benzene is 0.5), and the saturated adsorption capacity of carbon tetrachloride is 0.47g/g (at 25°C, the relative pressure of carbon tetrachloride at adsorption equilibrium is 0.5).

Embodiment 7, the organobentonite (being called for short CTMAB bentonite) prepared by the ratio of 0.1mol cetyltrimethylammonium bromide/100g bentonite is at first used for adsorption treatment to contain the waste water of 1000mg/L p-nitrophenol (PNP), The saturated adsorption capacity of CTMAB bentonite is 96mgPNP/g, solid-liquid separation, CTMAB bentonite (PNP-CTMAB bentonite) after absorbing p-nitrophenol is dried in the air, and then dried at 80°C for 24h in an air atmosphere. Mix 14g of DNP-CTMAB bentonite with 13g of dodecylamine, stir and react at 50°C for 30min, slowly add 120ml of orthobutyl silicate dropwise, and stir at room temperature for 4h after the dropwise addition. Separation of solid and liquid, drying of the solid part, and finally heating up to 560°C at a rate of 3°C/min in an air atmosphere, and roasting for 6h to remove surfactants and adsorbed organic pollutants to obtain porous clay heterogeneous materials.

The main property indicators of the sample: the specific surface area is 560m ² /g, the pore volume is 0.22cm ³ /g, the average pore diameter is 25nm, the thermal stability temperature is at least 750°C, and the benzene saturated adsorption capacity is 0.30g/g (at 25°C, when the adsorption equilibrium The relative pressure of benzene is 0.5), and the saturated adsorption capacity of carbon tetrachloride is 0.42g/g (at 25°C, the relative pressure of carbon tetrachloride at adsorption equilibrium is 0.5).

Claims (5)

1. adobe isomery material synthesis method, it is characterized in that with the organobentonite behind the adsorption treatment organic wastewater as synthetic main body clay raw material, add cosurfactant as the template direction agent, instruct neutral inorganic precursor between bentonite bed, to carry out interlayer hydrolysis and condensation polymerization in the duct, form inorganic-organic compound intermediate; The compound intermediate of organic and inorganic obtains adobe isomery material after surfactant is removed in roasting.

2. a kind of adobe isomery material synthesis method according to claim 1 is characterized in that the concrete preparation process of said synthetic method is as follows:

1) with the organobentonite behind the adsorption treatment organic wastewater through Separation of Solid and Liquid, in air, dry, 50～100 ℃ of drying 12～24h are to remove ADSORPTION STATE moisture then;

2) with dried organobentonite and cosurfactant by organobentonite: cosurfactant=1: 0.5～mass ratio mixed in 1: 2, in 20～80 ℃ of stirring reaction 15～60min;

3) at room temperature, by organobentonite: the mass ratio of neutral inorganic precursor=1: 100～1: 200 slowly splashes into neutral inorganic precursor, stirring reaction 2～8h;

4) Separation of Solid and Liquid need not washing, and solid portion dries under the room temperature in air, obtains inorganic-organic compound intermediate;

5) under air atmosphere, be warming up to 500～750 ℃ with 2～5 ℃/min speed, roasting 5～10h is to remove the organic pollution of surfactant and absorption.

3. a kind of adobe isomery material synthesis method according to claim 1 is characterized in that said organobentonite is that a kind of and bentonite of quaternary or alkyl pyridine type cationic surfactant reacts the organic clay that obtains.

4. a kind of adobe isomery material synthesis method according to claim 1 is characterized in that said cosurfactant is formula C _nH _N-1NH ₂Neutral amine, n is a carbon number, the n scope is 6～18.

5. a kind of adobe isomery material synthesis method according to claim 1 is characterized in that said neutral inorganic precursor is a kind of in methyl silicate, ethyl orthosilicate, positive silicic acid propyl ester, the butyl silicate.