Abstract:
This invention describes the preparation of additive material and its application in the cigarette of tobacco. This material is titanate nanotube and was synthesized by using a hydrothermal route. Titanate nanotube can be used as additive material in the cigarette of tobacco and the harmful compounds in the mainstream cigarette smoke can be removed significantly.

Description:
TECHNICAL FIELD 
       [0001]    This invention describes the preparation of titanate nanotube and its application in the tobacco cigarette as additive material, in which the harmful compounds in the mainstream cigarette smoke can be removed significantly. 
       TECHNICAL BACKGROUND OF THE INVENTION 
       [0002]    Smoking has been proven to be significantly harmful effect on human&#39;s health. Cigarette smoke is composed primarily of tar, nicotine and carbon monoxide. Tar will increase a smoker&#39;s risk of lung cancer, emphysema and bronchial disorders; nicotine is highly addictive, while carbon monoxide causes the chance of cardiovascular diseases. In addition, tar contains various toxic or carcinogenic chemicals such as polycyclic aromatic hydrocarbons (PAHs) and tobacco-specific nitrosamines (TSNAs), even a trace amount of PAHs or TSNAs are able to cause serious health risk. Beside them, a lot of harmful compounds, including ammonia, hydrogen cyanide, aldehydes and phenolic compounds have also been recognized in cigarette smoke. 
         [0003]    To reduce toxic compounds in the mainstream cigarette smoke and decrease risk for the smokers, a series of additives and technologies have been developed. The additives were introduced into filter for capturing harmful compounds have been proven to be one of efficient routes and also received great attention. For instance, researchers in Nanjing University used zeolite and mesoporous silica coated with metals as the additives in the filter, the volatile nitrosamines in mainstream tobacco smoke (MS) can be captured efficiently. Chen et al. reported that carbon nanotubes can remove the nicotine and tar from MS. Hunan Tobacco Company utilized metal oxides (Al 2 O 3 , Fe 2 O 3 , Al 2 O 3 —Fe 2 O 3 ) as the additives in the filter, more than 28% of phenol on MS can be removed selectively. 
         [0004]    U.S. Patent (No. 20040025895) reported that the phenols in MS can be reduced efficiently using nanostructural Fe 2 O 3 . Another patent (U.S. Pat. No. 4,300,577) also described that the aldehyde, acrolein, crotonic aldehydes and hydrocyanic acid in MS can be removed simultaneously using an adsorbent containing amino group. However, the synthesis of these materials is very complicated, leading to increase cost of a cigarette. At the same time, the incorporated metal in cigarette filters might be inhaled into the human body and will cause unpredictable troubles. On the other hand, these materials in the cigarette filter can not remove simultaneously. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention is a new additive material in the cigarette filter for removing harmful compound from MS, which can be prepared simply. This material with a low cost and high safe for the smoker can simultaneously removed tar, nicotine, CO, NH 3 , hydrocyanic acid, pheniols, crotonic aldehydes and so on. 
         [0006]    5˜50 mg of titanate nanotubes were added in the filter tips of cigarettes. The synthetic route of titanate nanotubes is following: anatase TiO 2  powder (0.5˜100 g) and an aqueous solution of NaOH (5˜15 M, 10˜1000 mL) were mixed and then transferred into a Teflon container, which was kept in a Teflon-lined autoclave in an oven at 373˜423K for 1˜3 days. The white suspension was washed with 0.1 M HCl solution and deionized water several times until pH values were 1˜7, and then dried at 323˜373K for 1˜40 h. 
         [0007]    The advantages of the present invention: Firstly, the titanate nanotubes with a low cost and high safe can be prepared simply; secondly, the tar, nicotine, CO, NH 3 , hydrocyanic acid, pheniols and crotonic aldehydes in MS can be removed simultaneously when the titanate nanotubes were added in the filter of cigarette. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0008]      FIG. 1  X-ray powder diffraction (XRD) patterns of the titanate nanotubes were recorded using a diffractometer (Co Ka, PANalytical, X&#39;Pert). 
           [0009]      FIG. 2  Scanning electron microscope (SEM) of the titanate nanotubes were taken on a Hitachi S-4800. 
           [0010]      FIG. 3  Transmission electron micrograph (TEM) of the titanate nanotubes were taken on a JEOL 2010 instrument. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0011]    The Preparation of Titanate Nanotubes: 
         [0012]    Anatase TiO 2  powder (0.5˜100 g) and an aqueous solution of NaOH (5˜15 M, 10˜1000 mL) were mixed and then transferred into a Teflon container, which was kept in a Teflon-lined autoclave in an oven at 373˜423 K for 1˜3 days. The white suspension was washed with 0.1 M HCl solution and deionized water several times until pH values were 1˜7, and then dried at 323˜373 K in air for 1˜40 h. 
         [0013]    The synthesized titanate nanotubes has a layered structure, BET surface area is more than 300 m 2 ·g −1 . The length of nanotubes is typically ranging from several hundreds of nanometres to several tens of micrometres. The nanotube is composed of crystalline multilayer walls, in which the inner diameter and outer diameter are found to be ca.˜5 and 10 nm, respectively. 
       EXAMPLE 1 
       [0014]    Anatase TiO 2  (0.5 g) and an aqueous solution of NaOH (5 M, 10 mL) were mixed and then transferred into a Teflon container, which was kept in a Teflon-lined autoclave in an oven at 373 K for 1 day. The white suspension was washed with 0.1 M HCl or HNO 3  solution and deionized water several times until pH value of 1 was reached, and then dried at 373 K in air for 5 h. 
       EXAMPLE 2 
       [0015]    Anatase TiO 2  (1 g) and an aqueous solution of NaOH (10 M, 20 mL) were mixed and then transferred into a Teflon container, which was kept in a Teflon-lined autoclave in an oven at 393 K for 1 day. The white suspension was washed with 0.1 M HCl or HNO 3  solution and deionized water several times until pH value of 1 was reached, and then dried at 353 K in air for 10 h. 
       EXAMPLE 3 
       [0016]    Anatase TiO 2  (2 g) and an aqueous solution of NaOH (10 M, 50 mL) were mixed and then transferred into a Teflon container, which was kept in a Teflon-lined autoclave in an oven at 393 K for 3 days. The white suspension was washed with 0.1 M HCl or HNO 3  solution and deionized water several times until pH value of 1 was reached, and then dried at 353 K in air for 20 h. 
       EXAMPLE 4 
       [0017]    Anatase TiO 2  (10 g) and an aqueous solution of NaOH (10 M, 500 mL) were mixed and then transferred into a Teflon container, which was kept in a Teflon-lined autoclave in an oven at 403 K for 3 days. The white suspension was washed with 0.1 M HCl or HNO 3  solution and deionized water several times until pH value of 5 was reached, and then dried at 343 K in air for 40 h. 
       EXAMPLE 5 
       [0018]    Anatase TiO 2  (100 g) and an aqueous solution of NaOH (15 M, 1000 mL) were mixed and then transferred into a Teflon container, which was kept in a Teflon-lined autoclave in an oven at 423 K for 2 days. The white suspension was washed with 0.1 M HCl or HNO 3  solution and deionized water several times until pH value of 2 was reached, and then dried at 323 K in air for 30 h. 
         [0019]      FIG. 1  shows the XRD pattern of the titanate nanotubes. According to current structural investigations, it can be indexed to layered structural titanates (Na 2 Ti 3 O 7 , H 2 Ti 3 O 7 , or Na x H 2-x Ti 3 O 7 ). 
         [0020]    As depicted in  FIG. 2-3 , the titanate nanotubes are clearly observed whose lengths typically range from several hundreds of nanometres to several tens of micrometres. The nanotube is composed of crystalline multilayer walls, in which the inner diameter and outer diameter are found to be ca.˜5 and 10 nm, respectively. 
       Property Measurement 
       [0021]    The synthesized titanate nanotubes were added in the filter tips of cigarettes. Prior to smoking, all thus treated cigarettes were kept in a chamber of 60±3% relative humidity at 12 for more than 24 h. They were then machine-smoked under standard conditions. Cigarette smoke first passed through the additive, and then the smoke condensates were collected on Cambridge filter pads and weighed. The filter pads were extracted with a solvent and analyzed immediately by combined gas chromatography-mass spectrometry for nicotine and tar under the standard conditions ISO-10315 and ISO-4387, respectively. Based on the Health Canada Test Method, ammonia was determined by an ion chromatography and hydrogen cyanide was analyzed by an automated continuous flow colorimetric analyzer, while the carbonyls and phenolic compounds were measured by a high performance liquid chromatography. 
         [0000]    
       
         
               
             
               
               
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 The reduction results of the harmful compounds in cigarette smoke 
               
             
          
           
               
                   
                 Blank 
                 TNT 
                   
               
             
          
           
               
                   
                 Smoke analyte 
                 Yield 
                 Yield 
                 Red. % 
               
               
                   
                   
               
             
          
           
               
                   
                 tar (mg/cig) 
                 13.3 
                 4.1 
                 69.2 
               
               
                   
                 nicotine (mg/cig) 
                 1.2 
                 0.4 
                 66.7 
               
               
                   
                 NH3 (μg/cig) 
                 7.4 
                 0.2 
                 97.3 
               
               
                   
                 HCN (μg/cig) 
                 158.0 
                 89.2 
                 43.5 
               
               
                   
                 CO (mg/cig) 
                 18.1 
                 16.8 
                 7.2 
               
               
                   
                 Hydroquinone (μg/cig) 
                 71.9 
                 10.9 
                 84.8 
               
               
                   
                 Resorcinol (μg/cig) 
                 1.4 
                 0.5 
                 63.6 
               
               
                   
                 Catechol (μg/cig) 
                 72.4 
                 6.6 
                 90.8 
               
               
                   
                 Phenol (μg/cig) 
                 14.8 
                 1.4 
                 90.7 
               
               
                   
                 Formaldehyde (μg/cig) 
                 79.3 
                 24.0 
                 69.7 
               
               
                   
                 Acetaldehyde (μg/cig) 
                 474.4 
                 212.8 
                 55.1 
               
               
                   
                 Acetone (μg/cig) 
                 270.4 
                 214.4 
                 20.7 
               
               
                   
                 Acrolein (μg/cig) 
                 52.7 
                 30.4 
                 42.3 
               
               
                   
                 Propionaldehyde(μg/cig) 
                 53.2 
                 37.3 
                 29.8 
               
               
                   
                 Methylethylketone(μg/cig) 
                 82.9 
                 78.6 
                 5.2 
               
               
                   
                 Butyraldehyde (μg/cig) 
                 37.7 
                 28.8 
                 23.7 
               
               
                   
                 Crotonaldehyde (μg/cig) 
                 25.5 
                 9.6 
                 62.7 
               
               
                   
                   
               
               
                   
                 Red. = [Yield (Blank) − Yield (titanate nanotubes)]/Yield (Blank)] * 100; 
               
             
          
         
       
     
         [0022]    The above case is optimized based on our invention. Any change based on the technique on this invention, the function does not surpass the range of this invention, all belongs to the protection of this invention.