Improving MCM‐41 as a Nitrosamines Trap through a One‐Pot Synthesis

Abstract

Copper oxide was incorporated into MCM-41 by a one-pot synthesis under acidic conditions to prepare a new mesoporous nitrosamines trap for protection of the environment. The resulting composites were characterized by XRD, N2 adsorption-desorption, and H2 temperature-programmed reduction techniques, and their adsorption capabilities were assessed in the gaseous adsorption of N-nitrosopyrrolidine (NPYR). The adsorption isotherms were consistent with the Freundlich equation. The copper salt was deposited onto MCM-41 during the evaporation stage and was fixed on the host in the calcination process that followed. MCM-41 was able to capture NPYR in air below 373 K but not at 453 K. Loading of copper oxide on MCM-41 greatly improved its adsorption capability at elevated temperatures. The influence of the incorporation of copper into MCM-41 samples and the adsorption behavior of these samples are discussed in detail.

Effective nitrosamines trap derived from the in situ carbonized mesoporous silica MCM-41

“…7 displays their actual efficiency in reducing the nitrosamines content of smoke. There were 2.29 nmol cig −1 of nitrosamine in the main smoke, and MCM-41 adsorbed about 18% of them, similar to that reported previously [16]. Most of the carbonized samples had the higher efficiency than parent MCM-41 in eliminating nitrosamines in tobacco smoke, with the exception of AM-1073 whose performance (18%) was the same as that of MCM-41.…”

“…The second, CTAB disperses in the channel of as-synthesized MCM-41 like the spoke in wheel with cation head rooted on the silica wall [15], which will affect the carbonization of micelles and the distribution of newly formed carbon. Besides, MCM-41 can provide the stronger geometric confinement than SBA-15 toward the tiny adsorbates such as volatile nitrosamines due to its smaller pore size [15,16], which is useful for the efforts of eliminating the carcinogenic pollutant in environment.…”

“…For this purpose the carbon-silica composite will be applied to eliminate the nitrosamines in the main smoke of cigarette, because tobacco smoke contains 5200 compounds and in which it is very difficult to selectively remove nitrosamines [17]. On the other hand, N-nitrosopyrrolidine (NPYR) is chosen as the probe for laboratorial experiments since it is a common volatile nitrosamine in smoke with a structure of five-member ring [16,18], and its adsorption and catalytic degradation have been investigated on many porous samples [19].…”

Capturing nitrosamines in tobacco-extract solution by hydrophobic mesoporous silica

“…The pollution caused by smoking is a global problem and the nitrosamines in tobacco smoke are the most active carcinogenic hence it is necessary to reduce the nitrosamines level of smoke. Consequently, a lot of effort has been reported including the zeolite-like additive used in filter or tobacco rod of cigarette through the way of selective adsorption or catalytic degradation of nitrosamines [1][2][3][4]. It is well known that a considerable part of tobacco-specific nitrosamines (TSNA) in smoke, say, 40-46% of the N -nitrosonornicotine in the mainstream smoke is transferred from tobacco leaf [5], and moreover, most of the TSNA in smoke are adhered on the particles whose size achieve micrometer grade exceeding the pore diameter of zeolite or mesoporous silica so that the adsorbent cannot capture them [3].…”

Microwave‐induced degradation of nitrosamines trapped in zeolites

“…Different situation was observed on CMn composite where the highest catalytic activity emerged on the sample of CM5 (1.48 µmol g −1 ) whereas the value on CM10 dramatically declined to 0.59 µmol g −1 (Table 1). MCM-41 had a larger surface area (1122 m 2 g −1 [24] ), but a smaller pore volume (0.58 cm 3 g −1 ) and pore size (2.1 nm) than SBA-15, which caused the similar difference between CMn and CSn samples. For instance, CM5 possessed the pore size of 2.5 nm and the pore volume of 0.70 cm 3 g −1 , obviously smaller than that of CS5 though its surface area (1080 m 2 g −1 ) was larger.…”