Preparation Of Novel Porous Particle And The Study Of Its Harm Reduction Effectiveness For Mainstream Smoke

As one kind of excellent adsorbents, activated carbons (AC) have been widely used insugaring, medicine, food, chemical engineering and other industries. So far, among all theadditives in cigarette filter, AC is the most widely used and the most effective one. Itscontribution in reducing tar and harmful chemicals from mainstream cigarette smoke should notbe underestimated. However, AC filter also has some disadvantages, such as the influence on theflavor of the cigarette products. AC filter can remove certain harmful chemicals frommainstream cigarette smoke as well as some aroma components which can result in insufficientof aroma. At present, adding essence is the mainly solution to overcome this problem. Theresearches that specialize in the modification of AC to solve this problem are rarely reported. Inour country, most of the researches on AC used in cigarette filter are focus on that the reducingof tar, phenolic compounds, part of carbonyl compounds and other harmful chemicals withoutdeeply into micro-level. And seldom do the research on the adsorption effect of AC from its porestructure and surface chemical properties. Therefore, to find a sort of AC with specific porestructure which can remove more of harmful chemicals from mainstream smoke and does notinfluence the flavor of cigarette is particularly important.This paper discusses a new modification method to endow AC with selective adsorptivity.Basing on the findings of nonsolvent induced phase separation from a cellulose acetate (CA)ternary solution in a mixed solvent of acetone and water, we successfully covered a CA porousfilm on the surface of AC particles. Fixed the concentration of CA, we have got a series of CAporous films with different pore size through adjusting water content. Scanning electronmicroscopy (SEM) and Brunner-Emmet-Teller (BET) measurement were used to characterize thestructure properties of the CA films.To investigate the adsorption performance of modified AC particles in detail, benzene, pyrene, cinnamonitrile, phenol which are harmful chemicals and vanillin, benzoic acid, thymolwhich are aroma components, were selected as the model compounds used in the simulatingadsorption tests. All adsorption quantities of the AC samples were analyzed by high performanceliquid chromatography (HPLC) method. The adsorption results in gas condition indicate that themodified AC particles can absorb more harmful substances but much fewer aroma componentsthan the original AC. Contrast with the original AC, the adsorption capacity of the modified ACwith water content of5wt%increases about65%for benzene. But for benzoic, the adsorptioncapacity of the modified AC reduces more than half of the original one which demonstrates thatthe modified AC has improved selective adsorption property. The adsorption results in aerosolcondition also indicate that the modified AC particles can absorb more harmful substances butmuch fewer aroma components than the original AC. Contrast with the original AC, theadsorption capacity of the modified AC with water content of5wt%increases about97%forphenol. But for thymol, the adsorption capacity of modified AC reduces more than80%of theoriginal one.At the same time, we have also added the modified AC into the cigarette filter and studiedits harm reduction effectiveness for mainstream smoke compared with the original AC. Thecigarette smoke adsorption results show that the modified AC particles can absorb more harmfulsubstances, i.e., CO, HCN, NNK, B[a]P, phenol, crotonaldehyde, than the original AC. Theremoval effect is preferably. Contrast with the original AC, the removal of the modified AC withwater content of6.5wt%whose removal effect is relatively the best one increases5.4%and6.3%for B[a]P and NNN, respectively.