CN100560490C - The method of alkali-free Hydrothermal Preparation chrysotile nano-tubes - Google Patents

Abstract

A kind of method of alkali-free Hydrothermal Preparation chrysotile nano-tubes, its step is: (1) takes by weighing mass ratio is 1: 1 MgO and SiO ₂Each 1 gram of powder, the distilled water of adding 70ml after mixing, drops into reactor, sealed reactor; (2) rotating speed of the magnetic stirring apparatus of described reactor is 100r/min, through 3-4 hour reactor is warmed up to 350 ℃ by room temperature, and pressure reaches 6.5-7.5MPa, is incubated 38-42 hour, naturally cools to room temperature then, promptly.The chrysotile nano-tubes that is obtained is a kind of water chestnut square crystal structure, and its diameter is even, and external diameter is about 30～50nm, the about 6～8nm of internal diameter, and length reaches the hundreds of nanometer.The present invention is having only under the situation of distilled water with magnesium oxide and silicon oxide, and solution is successfully prepares chrysotile nano-tubes, environmentally safe under the neutral condition.

Description

The method of alkali-free Hydrothermal Preparation chrysotile nano-tubes

Technical field

The present invention relates to the preparation method of chrysotile nano-tubes, further be meant the method for synthetic chrysotile nano-tubes under alkali free environment.

Background technology

Chrysotile is a kind of natural many walls of hollow nanotube, and its chemical formula is Mg ₃Si ₂O ₅(OH) ₄This mineral substance is made up of accumulation horizon, and each layer structural unit is formed by connecting by active oxygen and " brucite " octahedral sheet by tetrahedral si-o film.It has non-inflammability, and resistance to chemical corrosion can be used for fire prevention, electrical isolation, material of construction aspect, and aspects such as fragility substrate and chemical filter.In addition, the matrix material of chrysotile adding inorganics and polymeric constituent formation is widely used in industry.In the nanosecond science and technology field, chrysotile has very high application potential.The chrysotile fiber is transparent, and pipeline enclosure is every greatly, and length can reach centimetre-sized, is a kind of comparatively ideal quantum wire growth templates.

Chinese scholars is attempted synthetic Mg ₃Si ₂O ₅(OH) ₄Nanotube.In the past few years, Falini etc. are with MgCl ₂, NaOH and mesopore silicon oxide are raw material, use hydrothermal method at 300 ℃ of growth piped Mg ₃Si ₂O ₅(OH) ₄Crystal; Xu etc. allow MgCO with solution method ₃4Mg (OH) ₂H ₂O and nanoporous silicon oxide react under 400 ℃ of conditions and obtained chrysotile nano-tubes in 4 hours; Foresti etc. adopt SiO ₂, MgCl ₂Preparation stoichiometry chrysotile in the NaOH aqueous solution; Malaysian China etc. adds MgO with deionized water, SiO ₂, be mixed into turbid solution, then with NaOH with solution pH value furnishing 13, made chrysotile nano-tubes in 36 hours in reaction kettle for reaction;

But they adopt to prepare chrysotile under alkaline condition, have environmental pollution.

Summary of the invention

The objective of the invention is,, propose a kind of method of alkali-free Hydrothermal Preparation chrysotile nano-tubes, under the condition of not using basic solvent, utilize the Hydrothermal Preparation chrysotile nano-tubes, environmentally safe at the defective that prior art exists.

Technical scheme of the present invention is, the method for described alkali-free Hydrothermal Preparation chrysotile nano-tubes is realized by following steps:

(1) takes by weighing MgO and SiO ₂Each 1 gram of powder, the distilled water of adding 70ml after mixing, drops in the reactor, seals this reactor; The granularity of used MgO is 325 orders, SiO ₂Granularity be 10nm-20nm;

(2) rotating speed of the magnetic stirring apparatus of described reactor is 100r/min, through 3 hours-4 hours reactor is warmed up to 350 ℃ by room temperature, and pressure reaches 6.5MPa-7.5MPa, is incubated 38 hours-42 hours, naturally cools to room temperature then, promptly.

Among the present invention, after above-mentioned reaction finished, remaining 7ml-8ml was yellow solution in the reactor, surveys its pH value, is about 7.0, was neutral; This has also confirmed the fact that pressure constantly descends in the insulating process.Experimental pressure has arrived 7.3MPa and has begun insulation, and through the insulation of 40h, pressure drops to 2MPa at last.Can infer thus pressure reduce with solution in water-content reduce very big relation arranged, illustrate that in insulating process the water of 60ml has been participated in reaction, product Mg nearly ₃Si ₂O ₅(OH) ₄In OH ^-Radical ion is by H ₂O provides; The OH key replaces alkali to provide by water in the product.Under neutral mild conditions, successfully prepare chrysotile nano-tubes, the restriction that can only obtain under alkaline environment before having broken through is more conducive to environmental protection.

The present invention is a raw material with magnesium oxide and silicon oxide, is having only under the situation of distilled water, and solution is successfully prepares chrysotile nano-tubes (referring to Fig. 1 to 6) under the neutral condition; The chrysotile nano-tubes that is obtained is a kind of water chestnut square crystal structure, and its diameter is even, and external diameter is 30nm-50hm, the about 6nm-8nm of internal diameter, and length reaches the hundreds of nanometer.The chrysotile nano-tubes for preparing under neutral environment can be used for study on the modification; And, study aspects such as its luminescent properties and electrical property as the template growth quantum wire semiconductor.

As known from the above, the present invention is a kind of method of alkali-free Hydrothermal Preparation chrysotile nano-tubes, under the condition of not using basic solvent, utilizes the Hydrothermal Preparation chrysotile nano-tubes, environmentally safe.

Description of drawings

Fig. 1, Fig. 2 are the SEM image of product;

Fig. 3, Fig. 4 are the TEM image of product;

Fig. 5, Fig. 6 are the HRTEM image of product.

Embodiment

The method of alkali-free Hydrothermal Preparation chrysotile nano-tubes of the present invention the steps include:

(1) takes by weighing MgO and SiO ₂Each 1 gram of powder, the distilled water of adding 70ml after mixing, drops in the reactor, seals this reactor; The granularity of used MgO is 325 orders, SiO ₂Granularity be 15nm;

(2) rotating speed of the magnetic stirring apparatus of described reactor is 100r/min, through 3.5 hours reactor is warmed up to 350 ℃ by room temperature, and pressure reaches 7MPa, is incubated 40 hours, naturally cools to room temperature then, promptly.

Claims (1)

1, a kind of method of alkali-free Hydrothermal Preparation chrysotile nano-tubes is characterized in that, its step is:

(1) takes by weighing MgO and SiO ₂Each 1 gram of powder, the distilled water of adding 70ml after mixing, drops in the reactor, seals this reactor; The granularity of used MgO is 325 orders, SiO ₂Granularity be 10nm-20nm;

(2) rotating speed of the magnetic stirring apparatus of described reactor is 100r/min, through 3 hours-4 hours reactor is warmed up to 350 ℃ by room temperature, and pressure reaches 6.5MPa-7.5MPa, is incubated 38 hours-42 hours, naturally cools to room temperature then, promptly.

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