Properties of Bamboo Charcoal and Cement-based Composite Materials and Their Microstructure

The objective of this work was to study the properties of bamboo charcoal and cement-based composite materials and their microstructure. The pastes with various bamboo charcoals were prepared and the relative properties such as setting times and strength were tested and the microstructures and pore characteristics of pastes with various bamboos were also studied. The experimental results indicated that bamboo charcoal affects the setting times of cement paste, but the introduction of water reducer relieves this condition. Bamboo charcoal also poses an impact on the hardened paste strength. The prominent strength decrease is found when more and larger size bamboo charcoal is mixed into the cement paste. Bamboo charcoal alters the paste microstructure and increases the porosity and pore volume, but it increases the pores with the diameter of less than 50 μm. The pastes with various bamboo charcoals are given with the good functions such as adjusting humidity and adsorption.

Co_(3)O_(4) with ordered pore structure derived from wood vessels for efficient Hg^(0) oxidation

Catalytic oxidation of Hgo to Hg~O is an efficient way to remove Hg^(0) from coal-fired flue gas.The catalyst with ordered pore structure can lower mass transfer resistance resulting in higher Hg^(0) oxidation efficiency.Therefore,in the present work,wood vessels were used as sacrificial template to obtain Co_(3)O_(4) with ordered pore structure.SEM and BET results show that,when the mass concentrations of Co(NO_(3))_(2)·6H_(2)O was 20%,the obtained catalyst(Co_(3)O_(4) [20%Co(NO_(3))_(2)])possesses better pore structure and higher surface area.It will expose more available surface active sites and lower the mass transfer resistance.Furthermore,XPS results prove that Co_(3)O_(4) [20%Co(NO_(3))_(2)]has the highest ratio of chemisorbed oxygen which plays an important role in Hg^(0) oxidation process.These results lead to a better Hg^(0) oxidation efficiency of Co_(3)O_(4) [20%Co(NO_(3))_(2)],which is about 90%in the temperature range of 200 to 350℃,Furthermore,Co_(3)O_(4) [20%Co(NO_(3))_(2)]has a stable catalytic activity,and its Hg^(0) oxidation efficiency maintains above 90%at 250℃even after 90 h test,A probable reaction mechanism is deduced by the XPS results of the fresh,used and regenerated catalyst of Co_(3)O_(4) [20%Co(NO3)2].Chemisorbed oxygen can react with Hg^(0) forming HgO with the reduction of Co^(3+)to Co^(2)+.And lattice oxygen and gaseous oxygen can supplement the consumption of chemisorbed oxygen to oxidize Co^(2+)to Co^(3+).

Pore structure of SWNTs with high hydrogen storage capacity

This paper reveals, by analyses of nitrogen cryo-adsorption isotherm, the energetic and structural heterogeneity of single-walled carbon nanotubes (SWNTs) which has a high hydrogen storage capacity. It was found that SWNTs had manifold pore structures and distributed surface energy. By comparison of the pore structures and energy distributions of SWNTs before and after hydrogen adsorption, it is preliminarily indicated that hydrogen adsorption occurred in micropores and mesopores with smaller diameter, and that the pores of different diameters determined different hydrogen adsorption processes and underwent different structure changes during hydrogen adsorption.