CN103933928B - Dehumidifying adsorbent and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of dehumidifying adsorbent and preparation method thereof, it comprises Si0 ₂with Al ₂0 ₃, and Si0 ₂with Al ₂0 ₃amount of substance than for 1:0.9 ~ 1.1; This preparation method comprises the following steps: magnetic separation baking step, calcination activation step, re-activation step, aging step, standing crystallization steps and washing and drying step, preparation method of the present invention have technique simple, be easy to the features such as operation, the inventive method preparation-obtained dehumidifying adsorbent has high hygroscopic capacity, desorption temperature also can save the features such as mass energy at 40 ~ 100 DEG C.

Description

Dehumidifying adsorbent and preparation method thereof

Technical field

The invention discloses a kind of dehumidifying adsorbent and preparation method thereof, the invention belongs to technical field of air purification.

Background technology

Air humidity is one and lives with people and to produce the important environmental parameters of close relation.The health of people is subject to the invasion and attack of " wetting ", and thermal balance is destroyed just has influence on health.The Yield and quality, intensity, outward appearance etc. of air humidity to product have great negative effect, and be that industrial products are produced, processed and vital factor in storage process, the production of a lot of product has very high requirement to ambient humidity.Particularly the requirement of new high-tech product to humidity is stricter.Can not produce under very large humidity, can not store in a humidity environment.

Museum, library etc., make collectibles never degenerate, indeformable, just must create good Conservation environment.These all be unable to do without dehumidifying technology.

Rotary dehumidifier belongs to an important branch of field of air conditioning, and runner is an one core component, the critical material of adsorbent runner especially.The hygroscopic agent extensively adopted at present is the composite, molecular sieve etc. of silica gel, halate and silica gel and halate.All there is shortcoming in various degree in these adsorbents, some hygroscopic capacities little at present, some poor stabilities.But it has a common shortcoming to be desorption and regeneration temperatures as high 140 ~ 180 DEG C, not only will consume the very large energy, also because this increasing the difficulty of unit design.

Molecular sieve is the moisture rack-like alumino-silicate porous mineral crystalline material that a class has marvellous pore passage structure and distinct crystal chemical property; not only there is predictable efficient function; also have based on multiple excellent properties such as the adsorptivity under ion-exchange and catalytics; be widely applied to each field such as petrochemical industry, intermetallic composite coating, metallurgy, machine-building, electronics, medicine, freezing, vacuum technique, agricultural, atomic energy, environmental protection, become a kind of important material in national economy.Adopt a large amount of waterglass, sodium metaaluminate and aluminum sulfate to make Material synthesis molecular sieve cost comparatively large, be mainly used in catalytic field.

Kaolin is a kind of natural minerals, and chemical molecular formula is Al ₂o ₃2SiO ₂2H ₂o.Main chemical compositions is Silicified breccias, is formed by one deck Si-O tetrahedron and the octahedra staggered accumulation of sharing by oxygen atom of one deck Al-O, can as the silicon source of synthesis of molecular sieve and aluminium source.Compared with the adsorbent synthesized with the gel method of routine, take kaolin as molecular sieve and the catalyst of Material synthesis, there is unique feature in grain size, hydrothermal stability, activity and preventing from heavy metal performance etc., and due to kaolin cheap, the adsorbent cost namely synthesized is low.Nano kaoline, due to huge specific area and the feature such as absorption property and stronger ion-exchange capacity, plasticity, has been used as the carrier of petrochemical industry synthesis industry catalyst, has had good stability.It yet there are no the report of application in the adsorbing domain of air-treatment at present.

Kaolin has abundant reserves in China, has now verified oil in place about 3,000,000,000 tons, and China is topmost kaolin producing country of the world, and output accounts for 78% of Gross World Product.Traditional chemical industry Material synthesis zeolite molecular sieve is replaced with the kaolin of wide material sources, relative low price, not only can efficiency utilization mineral resources, but also be the important channel of widening molecular sieve application and its potential value of exploitation.

Summary of the invention

An object of the present invention overcomes the deficiencies in the prior art, provides a kind of high hygroscopic capacity, desorption temperature at the dehumidifying adsorbent of 40 ~ 100 DEG C.

Another object of the present invention overcomes the deficiencies in the prior art, provides the preparation method that a kind of technique is simple, be easy to a kind of adsorbent that dehumidifies operated.

According to technical scheme provided by the invention, described dehumidifying adsorbent, it comprises Si0 ₂with Al ₂0 ₃, and Si0 ₂with Al ₂0 ₃amount of substance than for 1:0.9 ~ 1.1.

According to technical scheme provided by the invention, the preparation method of described a kind of adsorbent that dehumidifies comprises the following steps:

A, selection Si0 ₂with Al ₂0 ₃amount of substance ratio be that the magnetic separation of being carried out by kaolin of 2 ~ 2.5:1 is removed after impurity, dry under 100 ~ 200 DEG C of environment, being crushed to particle mean size after oven dry is again 0.10 ~ 0.30mm, obtains kaolin powder;

B, kaolin powder is carried out calcination activation, calcination activation temperature controls at 600 ~ 800 DEG C, and calcination activation time controling, at 0.5 ~ 2.5 hour, is once activated kaolin;

C, once will activate kaolin and to be added in alkali lye and to stir, mixed reactant is heated to 50 ~ 70 DEG C after stirring and carries out re-activation, the weight ratio once activating kaolin and alkali lye is 1:15 ~ 25, the concentration of alkali lye is 2 ~ 4.5mol/L, re-activation time controling was at 2 ~ 5 hours, and re-activation terminates to obtain re-activation kaolin;

D, adopt the frozen water mixing bath of 0 DEG C to carry out ageing re-activation kaolin, digestion time controls, at 1 ~ 3 hour, to obtain ageing mixture;

E, ageing mixture is warming up to 80 ~ 110 DEG C of standing crystallization 1 ~ 5 hour, obtains crystallization mixture;

F, adopt absolute ethanol washing to be 10 ~ 12 to its PH in crystallization mixture, then the crystallization mixture after washing is dried at 90 ~ 120 DEG C, obtain dehumidifying adsorbent.

Alkali lye described in step c is NaOH solution, Na ₂cO ₃solution, KOH solution or K ₂cO ₃solution.

Preparation method of the present invention have technique simple, be easy to the features such as operation, the inventive method preparation-obtained dehumidifying adsorbent has high hygroscopic capacity, desorption temperature also can save the features such as mass energy at 40 ~ 100 DEG C.

Detailed description of the invention

Below in conjunction with specific embodiment, the invention will be further described.

Embodiment 1

A kind of preparation method of the adsorbent that dehumidifies comprises the following steps:

A, selection Si0 ₂with Al ₂0 ₃amount of substance remove after impurity than the magnetic separation that kaolin is carried out for 2:1, dry under 100 DEG C of environment, being crushed to particle mean size after oven dry is again 0.30mm, obtains kaolin powder;

B, kaolin powder is carried out calcination activation, calcination activation temperature controls at 600 DEG C, and calcination activation time controling, at 2.5 hours, is once activated kaolin;

C, once will activate kaolin and to be added in NaOH solution and to stir, mixed reactant is heated to 50 DEG C after stirring and carries out re-activation, the weight ratio once activating kaolin and alkali lye is 1:15, the concentration of NaOH solution is 2mol/L, re-activation time controling was at 2 hours, and re-activation terminates to obtain re-activation kaolin;

D, adopt the frozen water mixing bath of 0 DEG C to carry out ageing re-activation kaolin, digestion time controls, at 1 hour, to obtain ageing mixture;

E, ageing mixture is warming up to 80 DEG C of standing crystallization 5 hours, obtains crystallization mixture;

F, adopt absolute ethanol washing to be 10 to its PH in crystallization mixture, then the crystallization mixture after washing is dried at 90 DEG C, obtain dehumidifying adsorbent, in this dehumidifying adsorbent, SiO ₂with Al ₂o ₃amount of substance than for 1:1.1.

Prepared dehumidifying adsorbent is 28 DEG C through being processed into corrugated honeycomb formula desiccant wheel in temperature, carries out moisture pick-up properties dynamic test under the environment of relative humidity 68%, the adsorbance of water is 17g/Kg, during regeneration temperature 80 DEG C, desorption rate is 93%, and regeneration temperature 40 DEG C of desorption rates are 66%.

Embodiment 2

A kind of preparation method of the adsorbent that dehumidifies comprises the following steps:

A, selection Si0 ₂with Al ₂0 ₃amount of substance remove after impurity than the magnetic separation that kaolin is carried out of 2.2:1, dry under 200 DEG C of environment, being crushed to particle mean size after oven dry is again 0.10mm, obtains kaolin powder;

B, kaolin powder is carried out calcination activation, calcination activation temperature controls at 800 DEG C, and calcination activation time controling, at 0.5 hour, is once activated kaolin;

C, will once activate kaolin and be added in Na ₂cO ₃stir in solution, mixed reactant is heated to 70 DEG C and carries out re-activation after stirring, the weight ratio once activating kaolin and alkali lye is 1:25, Na ₂cO ₃the concentration of solution is 4.5mol/L, and re-activation time controling was at 5 hours, and re-activation terminates to obtain re-activation kaolin;

D, adopt the frozen water mixing bath of 0 DEG C to carry out ageing re-activation kaolin, digestion time controls, at 3 hours, to obtain ageing mixture;

E, ageing mixture is warming up to 110 DEG C of standing crystallization 1 hour, obtains crystallization mixture;

F, adopt absolute ethanol washing to be 12 to its PH in crystallization mixture, then the crystallization mixture after washing is dried at 90 ~ 120 DEG C, obtain dehumidifying adsorbent, in this dehumidifying adsorbent, SiO ₂with Al ₂o ₃amount of substance than for 1:0.9.

Prepared dehumidifying adsorbent is 28 DEG C through being processed into corrugated honeycomb formula desiccant wheel in temperature, carries out moisture pick-up properties dynamic test under the environment of relative humidity 68%, the adsorbance of water is 15g/Kg, during regeneration temperature 80 DEG C, desorption rate is 91%, and during regeneration temperature 40 DEG C, desorption rate is 67%.

Embodiment 3

A kind of preparation method of the adsorbent that dehumidifies comprises the following steps:

A, selection Si0 ₂with Al ₂0 ₃amount of substance remove after impurity than the magnetic separation that kaolin is carried out for 2.5:1, dry under 150 DEG C of environment, being crushed to particle mean size after oven dry is again 0.20mm, obtains kaolin powder;

B, kaolin powder is carried out calcination activation, calcination activation temperature controls at 700 DEG C, and calcination activation time controling, at 1.5 hours, is once activated kaolin;

C, once will activate kaolin and to be added in KOH solution and to stir, mixed reactant is heated to 60 DEG C after stirring and carries out re-activation, the weight ratio once activating kaolin and alkali lye is 1:20, the concentration of KOH solution is 3mol/L, re-activation time controling was at 4 hours, and re-activation terminates to obtain re-activation kaolin;

D, adopt the frozen water mixing bath of 0 DEG C to carry out ageing re-activation kaolin, digestion time controls, at 2 hours, to obtain ageing mixture;

E, ageing mixture is warming up to 100 DEG C of standing crystallization 3 hours, obtains crystallization mixture;

F, adopt absolute ethanol washing to be 11 to its PH in crystallization mixture, then the crystallization mixture after washing is dried at 110 DEG C, obtain dehumidifying adsorbent, in this dehumidifying adsorbent, SiO ₂with Al ₂o ₃amount of substance than for 1:0.95.

Prepared dehumidifying adsorbent is 28 DEG C through being processed into corrugated honeycomb formula desiccant wheel in temperature, carries out moisture pick-up properties dynamic test under the environment of relative humidity 68%, the adsorbance of water is 17.5g/Kg, during regeneration temperature 80 DEG C, desorption rate is 95%, and during regeneration temperature 40 DEG C, desorption rate is 69%.

Embodiment 4

A kind of preparation method of the adsorbent that dehumidifies comprises the following steps:

A, selection Si0 ₂with Al ₂0 ₃amount of substance remove after impurity than the magnetic separation that kaolin is carried out for 2.4:1, dry under 180 DEG C of environment, being crushed to particle mean size after oven dry is again 0.25mm, obtains kaolin powder;

B, kaolin powder is carried out calcination activation, calcination activation temperature controls at 660 DEG C, and calcination activation time controling, at 1.5 hours, is once activated kaolin;

C, will once activate kaolin and be added in K ₂cO ₃stir in solution, mixed reactant is heated to 66 DEG C and carries out re-activation after stirring, the weight ratio once activating kaolin and alkali lye is 1:18, K ₂cO ₃the concentration of solution is 2.5mol/L, and re-activation time controling was at 4 hours, and re-activation terminates to obtain re-activation kaolin;

D, adopt the frozen water mixing bath of 0 DEG C to carry out ageing re-activation kaolin, digestion time controls, at 2.5 hours, to obtain ageing mixture;

E, ageing mixture is warming up to 95 DEG C of standing crystallization 2 hours, obtains crystallization mixture;

F, adopt absolute ethanol washing to be 10.5 to its PH in crystallization mixture, then the crystallization mixture after washing is dried at 115 DEG C, obtain dehumidifying adsorbent, in this dehumidifying adsorbent, SiO ₂with Al ₂o ₃amount of substance than for 1:1.05.

Prepared dehumidifying adsorbent is 28 DEG C through being processed into corrugated honeycomb formula desiccant wheel in temperature, carries out moisture pick-up properties dynamic test under the environment of relative humidity 68%, the adsorbance of water is 17.5g/Kg, regeneration temperature desorption rate 80 DEG C time is 96%, and regeneration temperature desorption rate 40 DEG C time is 69%.

Containing a certain amount of Silicified breccias in kaolin, can be used for synthesizing the adsorbent with certain adsorption capacity, but without modification kaolin due to activity lower, therefore it be not suitable for directly be used as sorbing material, so magnetic separation and fragmentation will be carried out to it, to increase its specific area.

By calcination activation step, mother crystal is destructurized, the hydrogen bond rupture of kaolin interlayer, the crystallization water removes, and the kaolin of orderly lamella crystal structure is transformed into the metakaolin of disordered structure, the moieties of mother crystal internal layer is exposed, and sloughing due to the crystallization water, form duct, the kind of surface-active point and increasing number simultaneously, formation has chemically active silica, alumina crystal structure, and its reactivity is increased.Control heating rate, final temperature and certain roasting time, perfect pore structure can be formed.

Can be made the activation completely of not fully activation in high-temperature activation by re-activation step, make siliceous raw material and aluminum raw material after the molten process of alkali, alkali plays mineralizer effect, can reach overall activation.Promote that in calcined kaolin, hexa-coordinate aluminium changes active four-coordination aluminium into, alkali promotes that sial polymeric form is to the transformation of the sodalite and highly active sodium metasilicate with β basket structure.

The crystallization rate of novel molecular sieve can be significantly improved by aging step, reduce product grains degree.

The present invention also can add diatomite, bentonite and bivalent metal ion etc. when re-activation.Bentonite is the moisture clay pit based on montmorillonite, has bloating tendency, caking property and adsorptivity; Diatomaceous main component is SiO2, has extremely strong absorption affinity, special vesicular structure and large specific area, and water absorption rate is 2 ~ 4 times of own vol.Add the sorbing material formed, adsorbance increases, and hole and crack are well, active high, easy desorption.

By crystallization steps, make ageing mixture be easy to crystallization saturated, be conducive to reducing crystal size.

Claims (2)

1. dehumidify the preparation method of adsorbent, it is characterized in that this preparation method comprises the following steps:

A, selection SiO ₂with Al ₂o ₃amount of substance ratio be the kaolin of 2 ~ 2.5:1, carried out magnetic separation and remove after impurity, dry under 100 ~ 200 DEG C of environment, being crushed to particle mean size after oven dry is again 0.10 ~ 0.30mm, obtains kaolin powder;

B, kaolin powder is carried out calcination activation, calcination activation temperature controls at 600 ~ 800 DEG C, and calcination activation time controling, at 0.5 ~ 2.5 hour, is once activated kaolin;

C, once will activate kaolin and to add in alkali lye and to stir, mixed reactant is heated to 50 ~ 70 DEG C after stirring and carries out re-activation, the weight ratio once activating kaolin and alkali lye is 1:15 ~ 25, the concentration of alkali lye is 2 ~ 4.5mol/L, re-activation time controling was at 2 ~ 5 hours, and re-activation terminates to obtain re-activation kaolin;

D, adopt the frozen water mixing bath of 0 DEG C to carry out ageing re-activation kaolin, digestion time controls, at 1 ~ 3 hour, to obtain ageing mixture;

E, ageing mixture is warming up to 80 ~ 110 DEG C of standing crystallization 1 ~ 5 hour, obtains crystallization mixture;

F, adopt absolute ethanol washing to be 10 ~ 12 to its pH in crystallization mixture, then the crystallization mixture after washing is dried at 90 ~ 120 DEG C, obtain dehumidifying adsorbent.

2. the preparation method of a kind of adsorbent that dehumidifies as claimed in claim 1, is characterized in that: the alkali lye described in step c is NaOH solution, Na ₂cO ₃solution, KOH solution or K ₂cO ₃solution.