CN101856606A

CN101856606A - Preparation method of modified silicon gel absorbing agent used for protecting on-vehicle fuel batteries

Info

Publication number: CN101856606A
Application number: CN201010203104A
Authority: CN
Inventors: 邱介山; 万鹏
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2010-06-11
Filing date: 2010-06-11
Publication date: 2010-10-13
Anticipated expiration: 2030-06-11
Also published as: CN101856606B

Abstract

The invention relates to a preparation method of a kind of modified silicon gel absorbing agent used for protecting on-vehicle fuel batteries, which belongs to the branch of the non-metallic inorganic material technology and is applied to the field of gas absorption and separation. The preparation method uses 3-aminopropyl triethoxysilane as amino modifying agents, uses tetraethoxy silane as silicon gel precursors, and prepares and obtains modified silicon gel with uniformly decorated amino groups in a porous silicon gel framework through adding a certain number of amino modifying agents in the gel forming stage. The absorbing agent can be used for removing a trace amount of sulfur dioxide in the air, so cathodic catalysts of on-vehicle proton exchange membrane fuel batteries are protected from the poisoning effect of the sulfur dioxide. Compared with the prior art, the invention has the following advantages that: (1) the obtained absorbing agent has better capability for absorbing the trace amount of sulfur dioxide than active carbon fiber, the effect is shown through longer penetrating time and larger saturation adsorption capacity, in addition, the absorbing agent still has good absorbing capability when the humidity is lower; and (2) the obtained absorbing agent has simple and convenient preparation method, the operation is easy, the condition is mild, and the effects of energy saving and environment protection can be obtained.

Description

One class is used to protect the modified silica-gel preparation of adsorbent method of on-vehicle fuel

Technical field

The present invention relates to the modified silica-gel preparation of adsorbent method that a class is used to protect on-vehicle fuel, belong to inorganic non-metallic materials science technology branch, be applied to gas absorption and separation field.

Background technology

Advantages such as fuel cell is in the mode of electrochemical reaction the chemical energy of fuel to be converted into the TRT of electric energy, has the energy conversion efficiency height, and is pollution-free, and noise is low are the first-selected cleaning of 21 century of generally acknowledging, generation technology efficiently.Wherein Proton Exchange Membrane Fuel Cells as the 5th generation fuel cell, because of having the energy conversion efficiency height, but room temperature starts fast, and the high outstanding advantage of specific power all has broad application prospects at aspects such as electric motor car, portable electric appts, stationary electric power plant and military special power supplies.Proton Exchange Membrane Fuel Cells generally adopts carbon black to support platinum (Pt/C) as catalyst at present, in use has the catalyst poisoning problem.And the impurity poisoning effect is one of main arch-criminal of fuel-cell catalyst reduction in service life, and these impurity mainly comprise CO, H ₂S, SO ₂, NO _xDeng.SO wherein ₂Harm to fuel-cell catalyst is particularly serious, and bibliographical information is arranged, even SO in the air ₂When content is 2ppm, also can cause battery performance to reduce more than 50%; When content increases to 5ppm, the general who has surrendered is near 80% under the performance.And all there is the serious problem of atmosphere pollution in the most of city of China, SO in the road air ₂Content is higher, therefore develop a kind of simple and easy, from air, remove the material of sulfur dioxide fast and efficiently, efficiently move in order to the protection fuel cell, be the problem that current scientific worker needs solution badly.

At present about sulfur dioxide removal research, developed both at home and abroad and many mature technique, comprise absorption method, electrochemical method, plasma desulfuration, microorganism removal method and photocatalysis etc.Absorption method can be divided into chemiadsorption and physisorphtion again, and the adsorbent that is widely used at present comprises document (Srivastava, R.K., W.Jozewicz and C.Singer.SO ₂Scrubbing technologies:A review.Environmental Progress, 2001,20 (4): 219-227) Zong Shu lime-limestone sorbent, document (Chen Yinfei, Zhuo Guanglan, Ge Zhonghua, Lv Dewei removes low concentration SO under the MgAlFe composite oxides high temperature ₂Performance, colleges and universities' Chemical Engineering journal, 2000,14 (4): 346-351) disclosed metal oxide sorbents, document (Liu, Y., Z.G.Zhang, Q.Tang and Z.D.Cao.Applying ACF todesulfurization process from flue gas.Plasma Science ﹠amp; Technology, 6 (4): 2419-2322) Zong Shu (modification) activated carbon fiber adsorbing substance etc.But these adsorbents are applied to high-load SO more ₂Remove, to also rare development of the absorption of trace sulfur dioxide research, and be in the starting stage especially at sulfur dioxide removal Study on Technology in the road air of on-vehicle fuel.Work under high temperature or high pressure and above these adsorbents are many, be not suitable for the job requirement of on-vehicle fuel normal temperature and pressure.And silica gel absorber is big owing to having specific area, is easy to carry out advantages such as chemical modification, will be highly suitable for the requirement of this research after modification.In view of the above, we have developed a kind of amido modified Bio-sil, and this adsorbent has shown the ability that well removes trace sulfur dioxide as the expection imagination.

Summary of the invention:

The purpose of this invention is to provide a kind of preparation method who possesses the amino modified silica gel of good trace sulfur dioxide adsorption capacity.

The technical solution used in the present invention is: a class is used to protect the modified silica-gel preparation of adsorbent method concrete steps of on-vehicle fuel as follows:

(1) be 2.15: 3.8: 1 according to mass ratio: 0.033 ratio is that the HCl solution of 0.05mol/l adds in the round-bottomed flask respectively successively with tetraethoxysilane, absolute ethyl alcohol, deionized water and concentration, stir, reacted 1-14 days, obtain transparent limpid sol precursor;

(2) with prepared sol precursor, with quality is its 0-3 absolute ethyl alcohol dilution doubly, splash into quality after mixing fast and be amino modified dose of sol precursor 11～33%, stir and obtain transparent solid gel down rapidly, after treating this solid gel ageing 0.5-3h, it is smashed, place baking oven to descend dry 1-3 days at 50-80 ℃; The even grinding of silica gel particle after the drying processing promptly got amino modified silica gel absorber.

Described amino modified dose is the 3-aminopropyl triethoxysilane.

The core of technique scheme is the selection of amino modified dose and preparing gel condition.The 3-aminopropyl triethoxysilane that is promptly added can covalently evenly be modified at amino in the Bio-sil skeleton after by the ethyoxyl hydrolytic condensation, helps rapid acquiring trace sulfur dioxide; Because the strong basicity of himself can play catalytic action to becoming the glue process, impel the quick formation of gel simultaneously.This method is chosen in and adds modifier A PTES again after the TEOS hydrolytic condensation forms colloidal sol, rather than with APTES and TEOS cohydrolysis, purpose is to avoid the strong basicity of APTES to make silica gel precipitate too fast formation, destroys sol-gel process, causes silica gel product specific area and porosity to reduce.

The invention has the beneficial effects as follows: it is amino modified dose with the 3-aminopropyl triethoxysilane that this class is used to protect the preparation method of the amino modified silica gel absorber of on-vehicle fuel; with the tetraethoxysilane is the silica gel presoma; by becoming the glue stage to add a certain amount of amino modified dose, be prepared into the modified silica-gel that evenly is modified with amino group in the Bio-sil skeleton.This modified silica-gel has the good ability that removes trace sulfur dioxide, compares with activated carbon fiber adsorbing substance to have longer time of break-through and bigger saturated adsorption capacity.This adsorbent can be used for removing of trace sulfur dioxide in the air, thereby protects vehicle-mounted fuel battery cathode with proton exchange film catalyst to avoid the poisoning effect of sulfur dioxide.Following advantage is compared with prior art arranged: can be the at normal temperatures and pressures efficient rapid acquiring trace sulfur dioxide of the adsorbent that (1) obtains; (2) this adsorbent has the ability of better adsorb traces sulfur dioxide than NACF, shows longer time of break-through and bigger saturated adsorption capacity, and still have better adsorption capacity than low humidity the time; (3) preparation method is easy, processing ease, mild condition, energy-conserving and environment-protective.

Description of drawings

Fig. 1 is the isothermal nitrogen adsorption desorption curve of amino modified silica gel absorber.

Fig. 2 is the pore size distribution curve of amino modified silica gel absorber.

Fig. 3 is amino modified silica gel and carbon fiber adsorption and catalytic combustion trace SO ₂Dynamic saturated adsorption capacity.

The specific embodiment:

The invention will be further described below by embodiment.

Embodiment one

(1) be 2.15: 3.8: 1 according to mass ratio: 0.033 ratio is that the HCl solution of 0.05mol/l adds in the round-bottomed flask respectively successively with tetraethoxysilane, absolute ethyl alcohol, deionized water and concentration, stir, reacted 1 day, obtain transparent limpid sol precursor;

(2) get the sol precursor that a certain amount of step (1) makes, without the absolute ethyl alcohol dilution, splashing into quality fast is the 3-aminopropyl triethoxysilane of sol precursor quality 11%, stirs after following 5 seconds and obtains transparent solid gel.Behind this solid gel ageing 0.5h, smash, place baking oven to descend dry 1 day at 80 ℃, the even grinding of the silica gel particle of drying promptly got amino modified silica gel absorber.

The desiccant gel intensity that obtains is little, grind into powder adsorbent easily, and product has the ability of good adsorption trace sulfur dioxide.The adsorbent specific area is about 520m ²/ g, average pore size is about 4nm.Isothermal nitrogen adsorption desorption curve and pore size distribution curve are as shown in Figure 1, 2.

When gas flow is 100sccm, SO ₂Concentration is 20ppm (N ₂Be carrier gas), relative humidity is 40% o'clock, (the about 1000m of specific area of viscose-based active carbon fiber under the dynamic saturated adsorption capacity of this adsorbent and the same terms ²About/g) compare and increased near 6 times, shown in the histogram among Fig. 3.

Embodiment two

(1) be 2.15: 3.8: 1 according to mass ratio: 0.033 ratio is that the HCl solution of 0.05mol/l adds in the round-bottomed flask respectively successively with tetraethoxysilane, absolute ethyl alcohol, deionized water and concentration, stir, reacted 14 days, obtain transparent limpid sol precursor;

(2) get the sol precursor that a certain amount of step (1) makes, adding quality is the absolute ethyl alcohol dilution of 3 times of colloidal sol quality, and splashing into quality fast is the 3-aminopropyl triethoxysilane of sol precursor quality 33%, and stirring down, 1min promptly obtains transparent solid gel.Behind this solid gel ageing 3h, smash, place baking oven to descend dry 3 days at 50 ℃, the even grinding of the silica gel particle of drying promptly got amino modified silica gel absorber.

The desiccant gel intensity that obtains is similar to product among the embodiment one.

Embodiment three

(2) get the sol precursor that a certain amount of step (1) makes, adding quality is the absolute ethyl alcohol dilution of 3 times of colloidal sol quality, and splashing into quality fast is the 3-aminopropyl triethoxysilane of sol precursor quality 11%, stirs promptly to obtain transparent solid gel down.Behind this solid gel ageing 0.5h, smash, place baking oven to descend dry 3 days at 80 ℃, the even grinding of the silica gel particle of drying promptly got amino modified silica gel absorber.

The silica gel absorber that obtains is similar to embodiment one, has good adsorb traces sulfur dioxide ability, and adsorption reaction speed is very fast, still has the good adsorption effect under the condition of high-speed.

Claims

1. a class is used to protect the modified silica-gel preparation of adsorbent method of on-vehicle fuel, and it is characterized in that: the concrete steps of this method are as follows:

2. a class according to claim 1 is used to protect the modified silica-gel preparation of adsorbent method of on-vehicle fuel, it is characterized in that: described amino modified dose is the 3-aminopropyl triethoxysilane.