Dynamic of CO adsorption in a fixed bed of microporous and mesoporous activated carbon impregnated with sodium hydroxide and the application of response surface methodology (RSM) for determining optimal adsorption conditions.

Microporous and mesoporous activated carbon produced from longan-seed biomass were impregnated with NaOH and used to capture CO from a simulated flue gas in a fixed-bed column. The process variables that were studied included types of activated carbon as characterized by the volume ratio of micropores and mesopores (V/V), adsorption temperature, NaOH loading, gas feed rate and the adsorbent amount. All five process variables affected the two important breakthrough parameters, namely the breakthrough time (t) and CO adsorption capacity at breakthrough time (q), with different trends and degrees.

The Enhancement of CO and CH Capture on Activated Carbon with Different Degrees of Burn-Off and Surface Chemistry.

Activated carbon derived from longan seeds in our laboratory and commercial activated carbon are used to investigate the adsorption of methane (CH) and carbon dioxide (CO). The adsorption capacity for activated carbon from longan seeds is greater than commercial activated carbon due to the greater BET area and micropore volume. Increasing the degree of burn-off can enhance the adsorption of CO at 273 K from 4 mmol/g to 4.

Improving porous properties of activated carbon from carbon gel by the OTA method.

High-surface-area microporous-mesoporous carbons were produced from carbon gel by applying the three consecutive steps of air oxidation, thermal treatment, and activation (the OTA method) to the gel. The formation of mesopores occurs both inside and outside the nanoparticles which form the carbon gel, while micropores are predominantly created within the nanoparticles. The OTA method offered a greater increase in pore volume and BET surface area of the resulting activated carbon in comparison with conventional CO activation either under the same activation conditions or at the same degree of carbon burn-off.

The Use of High Surface Area Mesoporous-Activated Carbon from Longan Seed Biomass for Increasing Capacity and Kinetics of Methylene Blue Adsorption from Aqueous Solution.

Microporous- and mesoporous-activated carbons were produced from longan seed biomass through physical activation with CO under the same activation conditions of time and temperature. The specially prepared mesoporous carbon showed the maximum porous properties with the specific surface area of 1773 m/g and mesopore volume of 0.474 cm/g which accounts for 44.

The Analysis of Pore Development and Formation of Surface Functional Groups in Bamboo-Based Activated Carbon during CO Activation.

Pore development and the formation of oxygen functional groups were studied for activated carbon prepared from bamboo () using a two-step activation with CO, as functions of carbonization temperature and activation conditions (time and temperature). Results show that activated carbon produced from bamboo contains mostly micropores in the pore size range of 0.65 to 1.

A New Approach for Controlling Mesoporosity in Activated Carbon by the Consecutive Process of Air Oxidation, Thermal Destruction of Surface Functional Groups, and Carbon Activation (the OTA Method).

A new and simple method, based entirely on a physical approach, was proposed to produce activated carbon from longan fruit seed with controlled mesoporosity. This method, referred to as the OTA, consisted of three consecutive steps of (1) air oxidation of initial microporous activated carbon of about 30% char burn-off to introduce oxygen surface functional groups, (2) the thermal destruction of the functional groups by heating the oxidized carbon in a nitrogen atmosphere at a high temperature to increase the surface reactivity due to increased surface defects by bond disruption, and (3) the final reactivation of the resulting carbon in carbon dioxide. The formation of mesopores was achieved through the enlargement of the original micropores after heat treatment via the CO gasification, and at the same time new micropores were also produced, resulting in a larger increase in the percentage of mesopore volume and the total specific surface area, in comparison with the production of activated carbon by the conventional two-step activation method using the same activation time and temperature.

Monte Carlo Simulation and Experimental Studies of CO, CH and Their Mixture Capture in Porous Carbons.

Adsorption of carbon dioxide and methane in porous activated carbon and carbon nanotube was studied experimentally and by Grand Canonical Monte Carlo (GCMC) simulation. A gravimetric analyzer was used to obtain the experimental data, while in the simulation we used graphitic slit pores of various pore size to model activated carbon and a bundle of graphitic cylinders arranged hexagonally to model carbon nanotube. Carbon dioxide was modeled as a 3-center-Lennard-Jones (LJ) molecule with three fixed partial charges, while methane was modeled as a single LJ molecule.

Computational methodology for determining textural properties of simulated porous carbons.

We have refined and improved the computational efficiency of the TriPOD technique, used to determine the accessible characteristics of porous solids with a known configuration of solid atoms. Instead of placing a probe molecule randomly, as described in the original version of the TriPOD method (Herrera et al., 2011), we implemented a scheme for dividing the porous solid into 3D-grids and computing the solid-fluid potential energies at these grid points.

Effects of gasifying conditions and bed materials on fluidized bed steam gasification of wood biomass.

The effect of steam gasification conditions on products properties was investigated in a bubbling fluidized bed reactor, using larch wood as the starting material. For bed material effect, calcined limestone and calcined waste concrete gave high content of H(2) and CO(2), while silica sand provided the high content of CO. At 650 degrees C, calcined limestone proved to be most effective for tar adsorption and showed high ability to adsorb CO(2) in bed.