Chun Fang Zhou

Fabrication of photoluminescent ZnO/SBA-15 through directly dispersing zinc nitrate into the as-prepared mesoporous silica occluded with template

Photoluminescent ZnO/SBA-15 mesoporous materials are prepared by directly grind zinc nitrate into the as-prepared samples occluded with template, and this solvent-free method not only saves time and energy, but also enables a large amount of zinc oxide to be highly dispersed in the channels of mesoporous silica. The resulting composites exhibit photoluminescence (PL) properties with the ZnO quantum confinement, and the dispersed ZnO in SBA-15 illustrates a similar UV emission to crystalline ZnO nanostructures. Besides, this photoluminescence is used to try to detect the nitrosamine content in solution by quenching PL spectra for the first time, suggesting potential applications of ZnO/SBA-15 in sensing carcinogens such as N′-nitrosonornicotine (NNN) in the environment.

Solvent-free surface functionalized SBA-15 as a versatile trap of nitrosamines

Dispersion of copper oxide via a solvent-free method enables mesoporous silica SBA-15 to become a versatile trap of nitrosamines, exhibiting a high capability to capture volatile nitrosamines and tobacco special nitrosamines (TSNA). 3%CuO/SBA-15 can remove 85% of N-nitrosopyrrolidine (NPYR) in gaseous flow, one fifth more than that by the analogous via one-pot method, while 5%CuO/SBA-15 traps all N-nitrosonornicotine (NNN) in solution with a concentration of 0.6 mmol l−1, superior to NaY zeolite. The dispersion of the copper guest in SBA-15 is assessed by XRD, H2-TPR, NO2-TPD and UV-Vis methods.

Adsorption and room temperature degradation of N-nitrosodiphenylamine on zeolites

N-Nitrosodiphenylamine (NDPA) is selected as a model compound to reveal the specific adsorption and catalytic function of zeolites in the removal of carcinogenic nitrosamines from the environment. The bulky NDPA molecule is indeed adsorbed in the zeolite KA having a small aperture, by insertion of the –N–NO group into the channel and involving a specific interaction between the nitrosamine and the zeolite. Degradation of NDPA at room temperature on zeolite is reported for the first time, revealing the potential applicability of zeolites to eliminate nitrosamines under mild conditions. The acidity of zeolite is the key factor determining its ability to degrade NDPA and, among the zeolites evaluated, Hβ is the most effective catalyst with an activity much higher than that of other zeolites at ambient temperature.

New efficient Al-containing SBA-15 materials for removing nitrosamines in mild conditions

SBA-15 was modified by incoporating acidic zeolite fragments or plugging, and showed a significantly enhanced efficiency for the removal of nitrosamines in mild conditions. The impact of pore structure and acidicity of mesoporous materials on their adsorptive feature is examined, in comparison with those coated with copper oxide, in order to prepare new functional materials for environment protection.

Adsorption of bulky nitrosamines on zeolite with small pore size

Abstract Adsorption of bulky nitrosamines like N -nitrosohexamethyleneimine (NHMI) and N ′-nitrosonornicotine (NNN) on the zeolite with small pore size was firstly studied by use of TPSR (temperature programmed surface reaction), selective adsorption and FTIR methods, and the adsorption manner was discussed combined with simulation of the structure of nitrosamines. Both NNN and NHMI could be adsorbed on zeolite KA and NaA, furthermore they can be degraded in the process of TPSR, though the pore size of adsorbent was much smaller than the molecular diameter of the adsorbate.

Generating selective adsorptive sites on activated carbon

Micro-control of activated carbon surface by metal oxides was performed, in order to eliminate nitrosamines in environment, especially in cigarette smoke for the first time. Coating alumina and zinc oxide can promote the adsorption of nitrosamines in activated carbon, opening new avenues to generating selective adsorption sites on amorphous material through the modification on the polarity of surface.

Investigation on the adsorption of nitrosamines in zeolites

The function of zeolites as the capturer of nitrosamines is depicted in this paper. N -nitrosodimethylamine (NDMA) and N -nitrosopyrrolidine (NPYR) can be selectively adsorbed by zeolite NaY or NaZSM-5 in solution or gaseous phase. The adsorption capacity of zeolite is discussed in terms of adsorbate-adsorbent interaction, involving their pore structure and electrostatic attraction along with the impact of adsorption temperature. In addition, one of the tobacco specific nitrosamines, N′ -nitrosonornicotine (NNN), is also employed as a probe to explore how the bulky nitrosamines are adsorbed by zeolites. The especial function of adsorption enables zeolites to be utilized for removal of nitrosamines in environment.