CN102941058A - Mesoporous iron oxide-titanium dioxide adsorbent and preparation as well as application - Google Patents

Abstract

The invention discloses a mesoporous iron oxide-titanium dioxide adsorbent and its preparation and application. The adsorbent is an iron oxide-titanium dioxide composite with a mesoporous structure; the molar ratio of Fe:Ti in the adsorbent is 0.03~ 0.07:1; the specific surface of the adsorbent is 160-220m ² /g, and the pore diameter is 3.0-5.0nm; the preparation method is to dissolve titanium sulfate and iron source in water and pour it into chitosan solution to prepare a mixed solution, The obtained mixed solution is added dropwise into boiling water and maintained for 1-3 hours, filtered, the filter residue is dried and roasted to obtain a product; the adsorbent is applied to reduce hydrocyanic acid in cigarette smoke. The adsorbent has good stability, high hydrogen cyanide adsorption activity, simple preparation, convenient operation, and low cost. It is used as an adsorbent to reduce hydrogen cyanide in cigarette smoke, and has high adsorption efficiency, which can effectively reduce the hydrogen cyanide in smoke. Hydrocyanic acid, reducing the physical harm of smokers.

Description

A kind of mesoporous iron oxide-titanium dioxide adsorbent and its preparation and application

technical field

The invention relates to a mesoporous iron oxide-titanium dioxide adsorbent as well as its preparation method and application, and belongs to the field of cigarette harm reduction and tar reduction.

Background technique

In recent years, people have carried out a lot of research on reducing the release of hydrocyanic acid in cigarette smoke. The methods that can be used mainly include diluting the smoke concentration, adding expanded tobacco or tobacco sheets, adding combustion enhancers, and using catalysts. In the early 1980s, Kiyoshi Ichikawa of Japan invented an activated carbon filter [U.S. Patent 4414988] containing a solution of protoporphyrin compounds impregnated with chelated ferrous ions, which can effectively remove CO and benzo in the flue gas. [a] Pyrene and hydrocyanic acid, etc. Meng Zhaoyu et al. invented a surface-modified mesoporous silicon-based molecular sieve (such as MCM-41, SBA-15, etc.) adsorbent for cigarette tip rods and a preparation method thereof [CN101077223], adding this adsorbent to cigarette filters to produce The composite mouth stick can significantly reduce the content of harmful substances such as tar, HCN, low-molecular aldehydes, ketones, nitrosamines, and condensed ring aromatics in the smoke, and can improve the sensory quality of cigarettes at the same time. Metal ions such as copper, cobalt, chromium and silver are loaded on activated carbon by ion exchange method (WO99/11358 (1999)), and a kind of activated carbon adsorbent has been developed, which can effectively adsorb harmful substances such as HCN. However, in activated carbon The "carbon smell" of cigarettes brings unpleasant feelings to smokers. Patents CN141695A and CN1462652A etc. describe the role of catalytic oxidation method in reducing hydrocyanic acid in cigarettes, showing higher catalytic activity. However, the production cost is relatively high, and in the production process, there will be uneven distribution in a single cigarette, which is difficult to control.

In the documents searched, the active components of the catalysts or adsorbents used are loaded on the surface of the carrier, and under certain conditions, they show the characteristics of poor stability and rapid deactivation.

However, there are few reports on the preparation of composite metal oxide adsorbents with mesoporous structure and their use to reduce harmful substances such as hydrocyanic acid in mainstream cigarette smoke.

Contents of the invention

An object of the present invention is to provide a mesoporous iron oxide-titanium dioxide adsorbent with good stability and high hydrocyanic acid adsorption activity.

Another object of the present invention is to provide a method for preparing a mesoporous iron oxide-titania adsorbent with simple preparation, convenient operation and low cost.

Another object of the present invention is to provide the above-mentioned mesoporous iron oxide-titanium dioxide adsorbent as an adsorbent for reducing hydrocyanic acid in cigarette smoke, with high adsorption efficiency, which can effectively reduce hydrocyanic acid in smoke and reduce smoking. harm to the body.

The invention provides a mesoporous iron oxide-titanium dioxide adsorbent, the adsorbent is an iron oxide-titanium dioxide composite with a mesoporous structure; the molar ratio of Fe:Ti in the adsorbent is 0.03-0.07:1; The specific surface of the adsorbent is 160-220m ² /g, and the pore diameter is 3.0-5.0nm.

The present invention also provides a kind of preparation method of mesoporous iron oxide-titanium dioxide adsorbent as mentioned above, after dissolving titanium sulfate and iron source in water, pour into chitosan solution to prepare mixed solution, the mixed liquid drop obtained After adding to boiling water, keep it for 1~3h, filter, dry the filter residue, and roast to obtain the product.

In the above preparation method, the titanium sulfate and the iron source are added in an amount of Fe:Ti in a molar ratio of 0.03-0.07:1.

The iron source is one or more of ferrous nitrate, ferrous sulfate, ferrous citrate and ferrous chloride.

The chitosan solution described in the above preparation method is a chitosan acetic acid solution, wherein the acetic acid accounts for 5 to 15% by volume of the solution, and the concentration of chitosan in the solution is 50 to 100g /L.

In the above preparation method, the calcination temperature is 500-600°C, preferably 550°C; the calcination time is 1-2h, preferably 1.5h.

The present invention also provides an application of the above-mentioned mesoporous iron oxide-titanium dioxide adsorbent, specifically using the mesoporous iron oxide-titanium dioxide composite as the adsorbent to reduce hydrocyanic acid in cigarette smoke.

The above-mentioned application is to press the adsorbent into tablets, sieve, select 40-60 mesh particles, and disperse them in the cellulose acetate tow of the cigarette filter rod. It is preferable to make a binary composite filter stick containing 15-30 mg of adsorbent in each filter stick.

The specific preparation process of the mesoporous iron oxide-titanium dioxide adsorbent of the present invention and the preparation of the cigarette holder containing the adsorbent: dissolving titanium sulfate and iron source in deionized water, and then pouring into the solution containing 50 ~ 100g/L chitosan CH ₃ COOH solution (5-15% acetic acid by volume), stir evenly; then slowly add this solution into the boiling water solution, and keep it for 1.5-3 hours under vigorous stirring. Then filter and dry at room temperature for 12-36 hours. Calcined at 500-600°C for 1-2 hours in an air atmosphere to obtain the product.

The prepared mesoporous iron oxide-titanium dioxide adsorbent was pressed into tablets and sieved, and the 40-60 mesh particles were selected and dispersed in the acetate tow to make a binary composite filter rod for cigarettes, and the composite filter rod was wound into cigarettes. Each filter stick contains 15-30mg of adsorbent

Beneficial effects of the present invention:

In the prior art, metal oxides are loaded on the mesoporous carrier, but the loading is often uneven and not firm, which affects the efficiency of adsorption. The mesoporous iron oxide-titanium dioxide described in the present invention is different from the traditional supported iron oxide/mesoporous TiO ₂ or supported Fe ₂ O ₃ /TiO ₂ , and its outstanding feature is that the active components are embedded in the carrier skeleton structure, It is integrated with the carrier, which is beneficial to the stability and dispersibility of the active ingredient, reduces the loss of the active ingredient, and makes it have higher activity. Moreover, the adsorbent is simple in preparation method, convenient in operation and low in cost; when it is applied to cigarette mouthpieces, it can effectively reduce the potential harm caused by low activity components such as hydrocyanic acid. The invention has simple preparation, convenient operation and low cost.

Detailed ways

The following examples are intended to further illustrate the present invention rather than limit the present invention.

Example 1

4.02 g Ti(SO ₄ ) ₂ 9H ₂ 0 and 0.09 g ferrous nitrate (anhydrous) were dissolved in 5 ml deionized water, and then poured into 10 ml CH ₃ COOH solution containing 0.75 g chitosan (10% V/ V), stir well. This solution was then slowly added to 100 ml of boiling water and kept under vigorous stirring for 2 hours. Then filter and dry at room temperature for 24 hours. Calcined at 550°C for 1.5 hours in air atmosphere to obtain the product, which is marked as meso-Fe ₂ O ₃ -TiO ₂ . The specific surface of meso-Fe ₂ O ₃ -TiO ₂ measured by low temperature N ₂ adsorption-desorption method is 207m ² /g, and the average pore diameter is 3.9nm;

Tablet pressing, sieving, selecting 40-60 mesh particles and dispersing them in the cellulose acetate tow to make binary composite filter sticks for cigarettes, and rolling the composite filter sticks into cigarettes. Smoke on Filtrona COA200 linear smoking machine (puff volume 35ml/min), measure the content of hydrocyanic acid in cigarette smoke according to YC/T253-2008, and compare it with cigarettes without adding adsorbent. The results show that, compared with the control Compared with cigarettes, the added amount of adsorbent is different, and the reduction rate of hydrocyanic acid is different. When the added amount is 30mg/stick, 25mg/stick, 20mg/stick and 15mg/stick, the corresponding content of hydrocyanic acid in mainstream smoke The declines were 25.3%, 21.7%, 16.2% and 13.2% respectively.

Example 2

Change the amount of ferrous nitrate in Example 1 to 0.04g, and keep other conditions unchanged. The specific surface of the prepared adsorbent is ^213m2 /g, and the average pore diameter is 4.2nm; The particles are dispersed in the cellulose acetate tow to make binary composite filter rods for cigarettes, each cigarette filter rod contains 30 mg of catalyst, and the composite filter rods are wound into cigarettes. The results show that, compared with the control of cigarettes without adding the adsorbent, the adsorbent prepared by the invention can reduce the hydrocyanic acid content in the mainstream smoke by 9.3%.

Example 3

Change the ferrous nitrate consumption in embodiment 1 to 0.12g, other conditions are constant, the prepared adsorbent specific surface is 201m ² /g, and the average aperture is 4.2nm, the prepared adsorbent is pressed into tablets, sieved, Select 40-60 mesh particles and disperse them in cellulose acetate tow to make binary composite filter sticks for cigarettes. Each cigarette filter stick contains 30 mg of catalyst, and the composite filter sticks are rolled into cigarettes. The results show that, compared with the control of cigarettes without adding the adsorbent, the adsorbent prepared by the invention can reduce the hydrocyanic acid content in the mainstream smoke by 27.9%.

Example 4

Ferrous nitrate in Example 1 was changed to ferrous sulfate, and other conditions remained unchanged, the specific surface of the obtained adsorbent was ^183m2 /g, and the average pore diameter was 4.1nm; the prepared adsorbent was pressed into tablets and sieved , select 40-60 mesh particles and disperse them in cellulose acetate tow to make binary composite filter rods for cigarettes, each cigarette filter rod contains 30 mg of catalyst, and the composite filter rods are rolled into cigarettes. The results show that, compared with the control of cigarettes without adding the adsorbent, the adsorbent prepared by the invention can reduce the hydrocyanic acid content in the mainstream smoke by 27.4%.

Example 5

Ferrous nitrate in Example 1 was changed to ferrous chloride, and other conditions remained unchanged, the prepared adsorbent was pressed into tablets and sieved, and the obtained adsorbent had a specific surface area of ^211m2 /g and an average pore diameter of 4.2nm Select 40-60 mesh particles and disperse them in cellulose acetate tow to make binary composite filter sticks for cigarettes. Each cigarette filter stick contains 30 mg of catalyst, and the composite filter sticks are rolled into cigarettes. The results show that, compared with the control of cigarettes without adding the adsorbent, the adsorbent prepared by the invention can reduce the hydrocyanic acid content in the mainstream smoke by 23.8%.

Example 6

The ferrous nitrate in Example 1 was changed to a mixture of ferrous citrate and ferrous nitrate, and other conditions remained unchanged, the specific surface of the prepared adsorbent was 200~ ^205m2 /g, and the average pore diameter was 4.0~4.1nm; Prepare adsorbent, press tablet, sieve, select 40~60 mesh particles and disperse in acetate tow to make binary composite filter stick of cigarettes, each cigarette filter stick contains 30mg of catalyst, and roll the composite filter stick into cigarettes . The results show that, compared with the control of cigarettes without adding the adsorbent, the adsorbent prepared by the invention can reduce the hydrocyanic acid content in the mainstream smoke by 24.7%.

Claims (10)

1. mesoporous iron oxide-titanium dioxide adsorbent is characterized in that, described adsorbent is the iron oxide-titanium dioxide compound with meso-hole structure; The Fe:Ti mol ratio is 0.03 ~ 0.07:1 in the described adsorbent; Described adsorbent specific surface is 160～220m ²/ g, the aperture is 3.0～5.0nm.

2. preparation method who prepares mesoporous iron oxide-titanium dioxide compound, it is characterized in that, pour into after titanium sulfate and source of iron is water-soluble and prepare mixed liquor in the chitosan solution, keep 1 ~ 3h after being added drop-wise in the boiling water to the mixed liquor that obtains, filter, with filter residue and drying, roasting, obtain product.

3. preparation method according to claim 2 is characterized in that, titanium sulfate and the source of iron amount take Fe:Ti as mol ratio 0.03 ~ 0.07:1 adds.

4. preparation method according to claim 3 is characterized in that, described source of iron is ferrous nitrate, ferrous sulfate, ferrous citrate, one or several in the frerrous chloride.

5. preparation method according to claim 2 is characterized in that, described chitosan solution is chitosan-acetic acid solution, and wherein to account for the volume percent content of described solution be 5 ~ 15% to acetic acid, and the concentration of shitosan in described solution is 50 ~ 100g/L.

6. preparation method according to claim 2 is characterized in that, sintering temperature is 500～600 ℃; Roasting time is 1 ~ 2h.

7. preparation method according to claim 6 is characterized in that, sintering temperature is 550 ℃; Roasting time is 1.5h.

8. the application of the mesoporous iron oxide-titanium dioxide compound of each gained is characterized in that, the iron oxide-titanium dioxide compound that will have a meso-hole structure is applied to reduce hydrogen cyanide in the cigarette smoke as adsorbent.

9. application according to claim 7 is characterized in that, with described compound compressing tablet, sieve, chooses 40 ~ 60 order particles, and the acetate fibres that is scattered in cigarette filter rod is intrafascicular..

10. application according to claim 9 is characterized in that, makes the binary compound filter candle that contains adsorbent 15～30mg in every filter stick.