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Composite organic-inorganic bentonite material and its synthesis process

A technology of inorganic bentonite and composite materials, applied in the direction of inorganic chemistry, chemical instruments and methods, silicon compounds, etc., can solve the problems of reduced specific surface area and pore volume, low thermal stability of surfactants, and low thermal stability. Achieve large porosity and specific surface area, good removal effect, high thermal stability

Inactive Publication Date: 2007-11-07
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Surfactant-modified organic bentonite has the following problems when used as an adsorbent: (1) The interlayer of bentonite is occupied by modifier molecules, the specific surface area and pore volume decrease sharply, and the adsorption effect on low-concentration adsorbates is poor and in the gas phase The adsorption speed is slow during adsorption, and the mass transfer resistance is large when adsorbing gas; (2) The organic modifier is usually loaded on the bentonite by cation exchange or physical adsorption, and the force is weak, and it is easy to absorb organic matter in water or in the regeneration process. In addition, the thermal stability depends on the decomposition temperature of the modified surfactant, and the surfactants suitable for synthesizing organobentonite are not high in thermal stability, so the thermal stability is poor (<250°C), which makes regeneration difficult
The problem with silanized organic bentonite is that the reactive hydroxyl groups in the structure of bentonite are mainly located on the outer surface, and most of the hydroxyl groups are wrapped in the silicon-oxygen tetrahedron. The aluminum hydroxyl groups are non-reactive hydroxyl groups, so the result of direct silanization of bentonite is organic carbon The content is low, and the silane group is mostly located on the surface, which has little effect on the layer, far inferior to the organic bentonite modified by cationic surfactant
It not only has the advantages of traditional organic bentonite, but also overcomes the shortcomings of its small specific surface area and pore volume and weak adsorption capacity for low-concentration adsorbates to a certain extent.
At the same time, it was also found that after bentonite was modified by polymeric metal ion pillars, the CEC dropped sharply, and some cationic surfactants entered the interlayer through physical adsorption rather than cation exchange, so the surfactant loading decreased and it was easy to fall off, and it still has not been solved. The problem of low thermal stability
[0007] Although the thermal stability of conventional inorganic pillared bentonite is better than that of organic bentonite, it obviously does not have the ability of organic bentonite to increase the adsorption capacity through high organic carbon content. However, the thermal stability is still not improved compared with organic bentonite, and the problem that the surfactant is easy to fall off is also difficult to overcome

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022]Example 1, under the conditions of continuous stirring and a temperature of 60°C, within 4 hours, a sodium carbonate aqueous solution with a concentration of 1.0mol / L was added dropwise to 0.5mol / LAlCl of 2 times the volume of the sodium carbonate aqueous solution 3 ·6H 2 In the O aqueous solution, the OH in the mixed solution - with Al 3+ The concentration ratio was 2.4, and the stirring was continued for 2 hours after the dropwise addition was completed, then the heating was stopped, and left to age for 24 hours to obtain a pillar liquid. Heat the pillar liquid to 60°C and keep the temperature constant. According to the proportion of bentonite mass and pillar liquid volume ratio of 50g / L, the calcium-based bentonite with a montmorillonite content of 95% is gradually mixed within 1 hour under stirring conditions. Disperse into the pillar liquid, continue to stir for 4 hours after the dispersion is completed, cool to room temperature, and stand for 24 hours; filter and...

Embodiment 2

[0023] Embodiment 2, other conditions are identical with embodiment 1, and silylating reagent adopts trimethylchlorosilane [Cl 3 Si(CH 3 ) 3 ] to obtain organic-inorganic bentonite composites with a BET surface area of ​​180m 2 / g, the pore volume is 0.15cm 3 / g, the average pore diameter is 2.30nm, the organic carbon content is 7.3%, and the silyl group content is 99.2mmol / 100g. The FTIR characterization results confirm that the silyl groups are combined with the surface of the host material through the Si-C covalent bond. The TG / DTA analysis results show that, The highest thermal stability temperature is 214°C.

Embodiment 3

[0024] Embodiment 3, other conditions are identical with embodiment 1, and silylating agent adopts 3-aminopropyl group-triethoxysilane [(CH 3 CH 2 O) 3 CH 2 SiCH 2 CH 2 CH 2 NH 2 ] to obtain organic-inorganic bentonite composites with a BET surface area of ​​160m 2 / g, the pore volume is 0.12cm 3 / g, the average pore diameter is 2.35nm, the organic carbon content is 9.4%, and the silane group content is 90.5mmol / 100g. The FTIR characterization results confirm that the silane group is bound to the surface of the host material through the Si-C covalent bond. The TG / DTA analysis results show that, The highest thermal stability temperature is 412°C.

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Abstract

The present invention discloses composite organic-inorganic bentonite material and its synthesis process. The present invention prepares composite organic-inorganic bentonite material with bentonite as the main material, and through cation exchange reaction with the water solution of polyhydroxy aluminum for inorganic modification of bentonite, roasting to obtain aluminum pillared interlayer bentonite with high porosity, great specific surface area and reactive hydroxyl radical, and the final silanizing reaction to graft silane radical containing organic radical onto the aluminum pillared interlayer bentonite to obtain the composite organic-inorganic bentonite material. The composite organic-inorganic bentonite material features high porosity, great specific surface area, high organic carbon content and high hydrophobicity.

Description

technical field [0001] The invention belongs to the field of clay mineral processing and utilization, and specifically relates to an organic-inorganic bentonite composite material and a synthesis method thereof, in particular to organic-inorganic bentonite which can be used in the fields of organic waste gas and wastewater adsorption treatment through inorganic and organic modification successively. Composite materials and methods for their preparation. Background technique [0002] Bentonite is a typical 2:1 layered clay mineral composed of montmorillonite as the main mineral, and is one of the most widely used non-metallic minerals. Bentonite has good properties such as water absorption, cohesiveness, adsorption, catalytic activity, thixotropy, suspension, plasticity, lubricity and cation exchange, so it can be used as a binder, absorbent, adsorbent, filling Agents, catalysts, thixotropic agents, flocculants, detergents, stabilizers and thickeners, etc., are widely used i...

Claims

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Application Information

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IPC IPC(8): C01B33/44B01J20/10
Inventor 朱利中田森林
Owner ZHEJIANG UNIV
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