Ming Bo Yue

Efficient CO2 Capturer Derived from As-Synthesized MCM-41 Modified with Amine

A new strategy to synthesize a highly efficient CO(2) capturer by incorporating tetraethylenepentamine (TEPA) into as-synthesized MCM-41 (AM) is reported. The amine guest can be distributed in the micelle of the support, forming a web within the mesopore to trap CO(2) molecules and resulting in a high adsorption capacity for CO(2) up to 237 mg g(-1). Four samples of the as-synthesized MCM-41 with a different amount or type of surfactant are employed as supports to investigate the influence of micelles on the CO(2) adsorption, and the spokelike structure of the micelle in the channel of the support is proven to be essential to the distribution of guest amine. Among these supports, the AM sample is the most competitive due to the advantages of energy and time saving in preparation of the support along with the resulting higher CO(2) adsorption capacity. At the optimal loading of 50 wt % TEPA, the AM-50 sample exhibits a high adsorption capacity of 183 mg g(-1) in the sixth adsorption cycle at 5 % CO(2) concentration.

Directly transforming as-synthesized MCM-41 to mesoporous MFI zeolite

Mesoporous MFI zeolite is fabricated through impregnating a structure-directing agent into as-synthesized MCM-41 followed by dry-gel conversion to transform amorphous silica to zeolite crystal. The original surfactant in the as-synthesized MCM-41 is used as the necessary mesoporogen to direct the mesopore genesis of zeolites, using the process of streaming to spur the transformation and tailoring the texture of mesoporous ZSM-5 by adjusting the Si : Al ratio in the MCM-41 source. The resulting sample is characterized by X-ray diffraction, IR spectroscopy, TEM and N2 adsorption to evaluate the textural properties of the mesoporous zeolite. Two kinds of nitrosamines with different structures are used as probe molecules to survey the adsorption function of the resulting mesoporous zeolite. Mesoporous zeolites exhibit good adsorption capacities and exceed either microporous zeolite or mesoporous silica. This synthesis strategy omits the fabrication and removal of the carbon template and simplifies the synthesis process of mesoporous zeolites, saving energy and time.

Hierarchical Composites to Reduce N-Nitrosamines in Cigarette Smoke

In order to reduce the harmful constituents in cigarette smoke, two hierarchical composites were synthesized. Based on, zeolites HZSM-5 or NaY fragments were introduced into the synthetic system of mesoporous silica SBA-15 or MCM-41 and assembled with the mesoporous materials. These porous composites combine the advantages of micro- and mesoporous materials, and exhibit higher effects than activated carbon on reducing tobacco specific nitrosamines (TSNA) and some vapor phase compounds in smoke.

Attempts to Synthesize Zeolitic Composites from Stellerite

A feasible method to synthesize NaA and NaY zeolite from stellerite, the very cheap raw material found in China, was reported in this article to reduce the cost of zeolite synthesis for the first time. After stellerite is calcined above 973 K with sodium carbonate, this natural zeolite can be slowly dissolved in alkali solution and partly forms the gels, then transforms to zeolite NaA or NaY by structural rearrangement. The effect of synthetic conditions such as the ratio of different cation used in the reactive mixture on the resulting zeolite is examined. Furthermore, a new NaA/MCM-41 composite possessing both micropore and mesopore is synthesized by adding the NaA zeolite into the synthetic system, and the impact of zeolite additive on the pore structure of final porous composite is also explored.