(674a) Soluble Inert Template for Preparing Nanostructured Carbon Materials From Forest and Plant Bioproducts

Nanostructured carbon materials is critical for multiple purification/separation processes such as water purification, natural gas purification, as well as used as catalyst supports for catalytic chemical processes, and advanced energy storage materials. Soluble inert templates, which reduce preparation cost by simplifying post template removal steps, are most hopeful substitutes for silica or other insoluble porous templates in preparation of nanostructured carbon materials. However, until now, the role of inert salts, such as NaCl, in preparation of nanostructured carbon materials is not clear. In references for ultrasound spray pyrolysis, soluble salts, generated in degradation of precursors or added into precursor solutions, have been recognized as temporary template for synthesis mesoporous or nanostructured carbon materials, while NaCl was identified as chemical activation catalyst for dehydration and irritation in preparing activated carbon with high surface from nuts shell.

In this project, porous structure of carbon materials was also modified by changing salt composition and preparation parameters such as feedstock, temperature procedure, gas composition of atmosphere, and gas flow rate. The pore structure of generated carbon materials were characterized with N₂ isothermal adsorption using a Micromeritics ASAP2010  automated gas adsorption analyzer. Specific surface areas were calculated using the Brunauer–Emmett–Teller (BET) model for the nitrogen isotherm.

Inert soluble salts such as NaCl and KCl were used as templates, while carbon dioxide (CO₂), carbon monoxide (CO), and steam (H₂O) were used as the activating agents to simulate syngas and flue gas process streams in heat treatment of feedstock. The amount of CO₂ in the gas mixture was diluted with inert N₂ while the total flow was held constant to verify catalytic effect of salts. The influence of syngas composition with varying ratios of CO₂:CO is studied to determine the optimum and tolerable amount of CO in the activating agent. 

Therefore, nanostructure of carbon materials has been rationally manipulated by changing salt composition and preparation parameters such as feedstock, temperature procedure, gas composition of atmosphere, and gas flow rate in this project. Furthermore, the nanostructured carbon material, with hierarchical porous structure, was prepared from different herbaceous feedstock in this project.  The results of this project shown that inert soluble salts, such as NaCl and KCl, not only functioned as template for forming mesoporous structure but also as catalysts for speeding up generation of microporous structure through gasification of biomass in gas containing steam, CO₂ or O₂.