Papers by Keyword: Oxygen Functional Groups

Abstract: The aim of this study is to investigate changes in microstructure and oxygen functional groups of liquefied wood activated carbon fibers using density functional theory, FTIR, X-ray photoelectron spectroscopy. Samples were immersed with hydrogen peroxide (H₂O₂) at three concentrations (15, 20, and 25 wt%), three temperatures (90, 70, and 50 °C) for three periods of time (1, 2, and 3 h). The results reveals that the pores average radius narrow, and micropores turn into mesopores or macropores with the increasing process, which brings about the surface area of treated samples decrease. Numerous oxygen functional groups are observed in the treated samples, and the ratios of oxygen and carbon increase from 3.2% before treated to 14.7% with H₂O₂ modification. The results confirm that the average pore radius and surface area decrease during treatment due to concentration and temperature. What is more, oxygen functional groups increase significantly with increasing treatment concentration.

Abstract: For solving the problems of high energy consumption and high capacity of water-absorption, microwave dehydration technology of lignite was studied in this paper. A self-developed microwave system was used for the experiment on dehydration of lignite from eastern Inner Mongolia. It was proved that the condition of moisture migration was improved and microwave dehydration had a unique mechanism. By analyzing the effects of microwave powers, coal particle sizes, and lignite qualities on drying characteristics, it was found that the moisture decreased when the microwave power increased. it was found that the higher the power was, the faster the moisture decreased; the smaller the particle size was, the faster the moisture decreased; the less the lignite was, the faster the moisture decreased. Through the scanning electron microscope analysis, it was concluded that microwave had no significant effect on the smooth particles, and the fibrous particles and clusters particles tended to be smooth under the effect of microwave. Therefore, the interface of lignite was relatively stable, and not easy to reabsorb water after microwave.

Abstract: Because of the increased demand for coal resources, the use of low-quality lignite increased. Heating-Pressing Utilizing is a better method to process fine lignite particles. The water resistance of lignite briquettes is important. In this study, the Baorixile lignite was dried in a lab-scale tube reactor and on pilot line. The oxygenic functional groups of lignite were analyzed at different temperature. The result indicated that carboxyl groups and phenols decreased as the temperature increasing, and phenols plays a more important role on the waterproof of lignite briquettes, especially at high temperature.

Abstract: In this study, a new nanoporous carbon was prepared by anodic oxidation treatment to remove noxic ammonia gas. The acid- and base values of the nanoporous carbon were determined by Boehm’s titration method. And, the surface properties of the carbons were investigated by XPS analysis. Also, N2/77K adsorption isotherm characteristics, including the specific surface areas and nano/micropore volumes were studied by BET and t-plot methods, respectively. The ammonia removal efficiency was confirmed by gas-detecting tube technique. As a result, it was revealed in the case of acidic treatment on nanoporous carbons that the ammonia removal was greatly effective due to the increase of OH groups in carbon surfaces without significant changes of nanostructural properties. It was then found that the acidic anodization of nanoporous carbons was a suitable method for the effective removal of ammonia gas, which could be attributed to the increase of acceptor-donor interactions between acidic oxygen functional groups of carbon adsorbent and basic adsorbate in an adsorbent-adsorbate system.