Activated carbon beads for smoking articles

Abstract

Smoking article include a smokable material and an activated carbon particle downstream of the smokable material. The activated carbon particle is produced from a whole seed. The activated carbon particle has a length, width and height. At least two of the length width and height are independently in a range from about 1 mm to about 7.5 mm. The particles can be spheroids, in which case the length, width and height would be the same or similar.

Claims

1. A smoking article comprising: a smokable material; and an activated carbon particle downstream of the smokable material, the activated carbon particle produced from a whole seed without mechanical disruption, wherein the activated carbon particle has a length, width, and height, wherein at least two of the length, the width and the height are independently in a range from 1 mm to 7.5 mm wherein the whole seed is selected from achira seeds, amapola or poppy seeds, amaranto or amaranth seeds, mijo or millet seeds, mostaza or mustard seeds, pimiento Negra or black pepper seeds, palmera or palm seeds, aladierno seeds, bayon seeds, ginebre or juniper seeds, sabina seeds and falsa pimiento or false pepper seeds, or a combination.

2. The smoking article of claim 1, wherein the activated carbon particle is free of binder.

3. The smoking article of claim 1, wherein the activated carbon particle is an ellipsoid.

4. The smoking article of claim 1, wherein the activated carbon particle is a spheroid.

5. The smoking article of claim 1, wherein the activated carbon particle is produced from carbonization and physical activation of the whole seed.

6. The smoking article of claim 1, wherein the seed from which the activated carbon is produced has a diameter in a range from 1 mm to 10 mm.

7. The smoking article of claim 1, wherein the activated carbon particle has a diameter in a range from 2.5 mm to 7 mm.

8. The smoking article of claim 1, wherein the activated carbon particle has a weight in a range from 10 mg to 60 mg.

9. The smoking article of claim 1, wherein the activated carbon particle has a weight in a range from 20 mg to 40 mg.

10. The smoking article of claim 1, wherein the activated carbon particle has a surface area (BET) in a range from 500 m.sup.2/g to 2500 m.sup.2/g.

11. The smoking article of claim 1, further comprising a filter having filter material, wherein the activated carbon particle is disposed within the filter material.

12. The smoking article of claim 11, wherein activated carbon in the filter consists essentially of the activated carbon particle.

13. A method for manufacturing a filter for a smoking article, comprising: carbonizing and activating a whole seed selected from achira seeds, amapola or poppy seeds, amaranto or amaranth seeds, mijo or millet seeds, mostaza or mustard seeds, pimiento Negra or black pepper seeds, palmera or palm seeds, aladierno seeds, bayon seeds, ginebre or juniper seeds, sabina seeds and falsa pimiento or false pepper seeds, or a combination, the whole seed having a length, width and height, wherein at least two of the length, width and height are independently in a range from 1 mm to 10 mm to form an activated carbon particle from the whole seed without mechanical disruption; and incorporating without mechanical disruption the activated carbon particle into the filter.

14. The method of claim 13, wherein the activated carbon particle has a length, width, and height, wherein at least two of the length, the width and the height are independently in a range from 1 mm to 7.5 mm.

15. A method for manufacturing a smoking article, comprising incorporating a filter manufactured according to claim 13 into the smoking article downstream of a smokable material.

Description

EXAMPLES

(1) A variety of seeds were obtained, carbonized and activated.

(2) Table 1 below presents a summary of the natural sizes of some of the seeds employed.

(3) TABLE-US-00001 TABLE 1 Summary of some seeds studied Seed ~Diameter Papaver rhoeas 1 Amaranthus 1 hypochondriacus Panicum miliaceum 2 Sinapis alba 3 Piper nigrum 4 Phoenix dactylifera 5 × 4 Canna indica 5 Rhamnus alaternus 6 Osyris lanceolata 5 Juniperus oxycedrus 7 Juniperus phoenicea 6 Schinus molle 4

(4) These natural seeds were dried (for example, in an oven at 110° C. for 3 h) and carbonized to obtain spherical chars (or oval chars, case of the palm tree). For obtaining spherical (or oval) activated carbons, the method used was direct physical activation (e.g., CO.sub.2 or steam) of the seeds (one step procedure) or the activation of the spherical biochars (two steps procedure).

(5) As an example, the dried seeds were introduced into a horizontal oven through which nitrogen (N.sub.2) was flowed at a rate of 300 ml/min. After purging the oven for a few minutes, seeds were carbonized with a heating rate of 5° C./min to 850° C., and this temperature was maintained for 2 hours. Then, carbonized seeds were weighed to calculate the yield of the charring process. Table 2 below presents humidity percent of the precursor seeds during such drying step, the yields of the carbonization process, and the diameter sizes of the resulting carbonized seeds.

(6) All of the selected seeds maintained their original shapes (spherical or oval), while the sizes of many of the seeds were somewhat reduced after the carbonization process. Interestingly all of the seed chars have suitable mechanical strength, and thus suitable activated carbon particles can be obtained from these seed chars.

(7) TABLE-US-00002 TABLE 2 Results of carbonized seeds under the following conditions: 850° C. at 5° C./min for 2 hours under 300 ml/min nitrogen flow Natural Natural Carbonized Yield Seed humidity (%) diameter (mm) diameter (mm) (%) Papaver rhoeas 5 1 1 22 Amaranthus 10 1 1 23 hypochondriacus Panicum 11 2 Agglomerated 23 miliaceum Sinapis alba 0 3 2 23 Piper nigrum 3 4 3 20 Phoenix 15 5 × 4 4 × 3 10 dactylifera Canna indica 7 5 4 22 Rhamnus 1 6 4 30 alaternus Juniperus 16 7 5 27 oxycedrus Juniperus 45 6 4 26 phoenicea Schinus molle 1 4 3 24

(8) During the example presented above (heating rate of 5° C./min), it was observed that in some cases (for example, Panicum miliaceum seeds) there was some agglomeration of the seeds due to the carbonization process. To prevent such agglomeration of the seeds, a lower heating ramp rate (1° C./min was) used. The seeds did not agglomerate at the reduced heating rate. Table 3 presents results using both heating rates (5° C./min and 1° C./min).

(9) TABLE-US-00003 TABLE 3 Results of the carbonized millet seeds at 850° C. for 2 hours with flow rate of nitrogen 300 ml/min but with different heating rate: a) 5° C./min and b) 1° C./min. Natural Carbonized seeds seeds 5° C./min 1° C./min Diameter (mm) 2 Agglomerated  2 Humidity (%) 15 — — Yield (%) — 23 23

(10) Some seeds were directly activated in one step preparation by physical activation (CO.sub.2, steam, or CO.sub.2 and steam) and some were first charred and then activated in a two steps preparation. As an example, seeds or carbonized seeds were introduced into the oven and were purged under an atmosphere of CO.sub.2 with a flow of 80 ml/min. After purging, the oven was heated at a rate of 5° C./min up to at 800° C. This temperature was maintained for a specific time for the activated seeds (between 5 and 30 hours). Finally, the activated seeds were weighed to calculate the activation percentage obtained in each case.

(11) Table 4 shows the activation conditions used for each carbonized seed as well as the information about the resulting diameter sizes and yields of the activation process.

(12) TABLE-US-00004 TABLE 4 Results of the activation process of different char seeds Natural Carbonized Activated Activation diameter diameter diameter time Activation Seeds (mm) (mm) (mm) (hours) (%) Sinapis 3 2 1 10 30 alba Phoenix 5 × 4 4 × 3 3 × 3 30 30 dactylifera Rhamnus 6 4 4 30 26 alaternus Canna 5 4 4 5 33 indica

(13) All the seeds maintained the spherical or ellipsoid morphology having suitable hardness after activation. The conditions for reaching a given activation degree depends on the precursor used.

(14) As an example of the suitability of these seeds to be charred or charred and activated can easily be observed considering than one of these seeds (Canna indica) was charred at a quite high carbonization temperature (900° C.) and activated at 880° C. very quickly (only 3 hours) up to a very high activation degree (89%). Even under these very severe conditions the resulting activated carbons maintain their spherical morphology having a suitable hardness and a very high BET surface area.

(15) The textural characterization of some activated seeds was performed using N.sub.2 adsorption at −196° C. and CO.sub.2 at 0° C. in a volumetric Autosorb-6B apparatus from Quantachrome. Before analysis, the samples were degassed at 250° C. for 4 h. The BET equation was applied to the nitrogen adsorption isotherm to get the apparent BET surface area. The Dubinin-Radushkevich equation was applied to the nitrogen adsorption isotherm to determine the total micropore volume and to the carbon dioxide adsorption isotherms to determine narrow micropore volumes. Table 5 summarizes some preliminary results of some activated seeds prepared from three different precursors.

(16) TABLE-US-00005 TABLE 5 The activation conditions and the textural properties of spherical activated (and oval) carbon prepared from different natural seeds. Textural properties Activation conditions V.sub.DR V.sub.DR T.sub.activation Time Activation S.sub.BET (N.sub.2) (CO.sub.2) Precursors (° C.) (h) (%) (m.sup.2/g) (cm.sup.3/g) (cm.sup.3/g) Phoenix 800 30 42 1143 0.52 0.44 dactylifera Rhamnus 800 30 26 812 0.38 0.36 alaternus Canna 800 5 33 856 0.39 0.35 indica Canna 880 3 89 1616 0.64 0.37 indica

(17) The results show that different activation degrees and different surface area can be obtained using different natural seeds. Thus, the selection of the seeds is relevant to obtaining a desired porosity range.

(18) Furthermore, the effects of activation time and activation temperature were studied. BY way of example, studies performed on Rhamnus seeds is presented. Some results obtained are shown in Table 6.

(19) TABLE-US-00006 TABLE 6 Activation conditions and textural properties of spherical activated carbon prepared from Rhamnus char using different activation time and temperature Textural properties Activation conditions V.sub.DR VDR T.sub.activation Time Activation S.sub.BET (N.sub.2) (CO.sub.2) Precursors (° C.) (h) (%) (m.sup.2/g) (cm.sup.3/g) (cm.sup.3/g) Rhamnus 800 10 6 492 0.20 0.25 Rhamnus 800 30 26 812 0.38 0.36 Rhamnus 800 40 33 889 0.40 0.33 Rhamnus 850 10 33 874 0.39 0.37

(20) Different char seeds of Rhamnus were activated using the same activation temperature (800° C.) but varying the activation times (10, 30 and 40 hours). The results show that increasing the activation time increases the activation degree and the surface area. In addition, the activation temperature was increased to 850° C. (setting an activation time of 10 hours) to study the effect of the activation temperature. As expected the results show that higher temperatures produce higher porosity activation using the same activation time.

(21) The surface oxygen concentration of a number of activated carbon particles was tested. For example, temperature-programmed desorption of oxygen on the surface of activated carbon particles derived from Columbian seeds was evaluated. The Columbian seeds were carbonized at 990° C. for 5 hours with a temperature ramp of 10° C. per minute under 100 ml/min N.sub.2 (22% yield) and were activated at 880° C. for three hours with a temperature ramp of 10° C. per minute under 80 ml/min CO.sub.2 (89% activation).

(22) The samples were characterized as follows. The characterization of all samples was performed using nitrogen (N.sub.2) adsorption at −196° C. and CO.sub.2 adsorption at 0° C. in a volumetric Autosorb-6B apparatus from Quantachrome. Before the analysis, the samples were outgassed at 250° C. for 4 hours. The BET equation was applied to the nitrogen adsorption data to get the apparent BET surface area (SBET) (Linares-Solano et al., Tanso 1998; 185:316-325). The Dubinin-Radushkevich equation was applied to the nitrogen adsorption data to determine the total micropore volume (pores with size <2 nm) V-DR-N2, and the total pore volume (V N2 at P/P0=0.95). The Dubinin-Radushkevich uation was applied to the carbon dioxide adsorption isotherms to determine narrow micropore volumes V-DR-CO2 (pores with size <0.7 nm).

(23) Surface oxygen content on the surface of the activated carbon can be determined by temperature-programmed desorption (TPD) under standard conditions. The surface oxygen content of the samples was determined as follows. TPD experiments were done in an equipment for differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA) (TA Instruments, SDT 2960 Simultaneous) coupled to a mass spectrometer (Balzers, OmniStar) to characterize the oxygen surface chemistry of all the samples, comprising measurement of water, carbon monoxide, carbon dioxide content under an inert atmosphere. See, for example, (i) Roman-Martinez et al. (1993), TPD and TPR characterization of carbonaceous supports and Pt/C catalysts, Carbon 31:894-902; (ii) Otake Y. and Jenkins R. G. (1993), Characterization of oxygen-containing surface complexes created on microporous carbon by air and nitric acid treatment, Carbon 31:109-21; and (iii) Zielge et al. (1996), Surface oxidized carbon fibers: I. Surface structure and chemistry, Carbon 34:983-98. In these experiments, 10 mg of sample were heated up to 950° C. (heating rate 20° C./min) under a helium flow rate of 100 ml/min.

(24) The total oxygen, CO and CO.sub.2 adsorption capacity of activated carbon particle derived from Columbian seeds is presented in Table 7 below.

(25) TABLE-US-00007 TABLE 7 Adsorption capacity of Columbian seed activated carbon particles Sample CO (μmol/g) CO.sub.2 (μmol/g) Total O (μmol/g) Carbonized seed 195 304 804 Activated seed 483 927 2338

(26) We can conclude that by varying the carbonization and activation conditions we can obtain seeds with different textural properties. Therefore, a selection of the natural seed precursor as well as a selection of the charring conditions (heating rate and temperature) and of the activation conditions (temperature and time) allow selection of the properties of the resulting biochar and bioactivated carbon (morphology, size, porosity, surface area and hardness).

(27) Thus, methods, systems, devices, compounds and compositions for ACTIVATED CARBON BEADS FOR SMOKING ARTICLES are described. Various modifications and variations of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are apparent to those skilled in chemistry; chemical engineering; filter manufacturing; cigarette manufacturing; or related fields are intended to be within the scope of the following claims.