Development of microporosity in carbons derived from alkali digested coal

Insight into hydroxides-activated coals: Chemical or physical activation?

“…As example, the reaction (6) is the result of two consecutive reactions (3) and (5) [34]. On the other hand, all reactions have been proposed based on the TPD results and, for a different activating agent, others reactions can be proposed in order to explain the experimental results.…”

“…The preparation of AC by chemical activation of anthracites was study by several authors [12,17,18,24,34]. In these studies, different parameters affecting the final pore texture of AC were analysed: pre-treatment of coal, activated agents, activating agent/coal ratio, maximum a) The influence of nitrogen flow.…”

Cd(II) binding by particulate low-rank coals in aqueous media: sorption characteristics and NICA–Donnan models

“…(4) to take into account the effects of electrostatics on the free energies of deprotonation, a model in which charges are assumed to be distributed in a three-dimensional array. The porous structure of coal has also been documented by gas adsorption [32], small-angle X-ray scattering, ultra-small-angle neutron scattering, and TEM imaging [52]. Values of specific surface area of Loy Yang coal typically lie in the range 5-200 m 2 /g.…”

“…All surface charges in I = 0.05-0.6 M can be predicted with a Langmuir-Freundlich isotherm coupled with surface electrostatic (e.g., Gouy-Chapman) or whole-volume electrostatic (e.g., Donnan) models. The specific surface area of the hydrated coal particles, determined by an electrostatic treatment of the data, were also suggested to be on the order of 1000 m 2 /g, while those of the dry coal particles, obtained by N 2 (g)-BET, were on the order of 5 m 2 /g [33] with CO 2 (g) micropore area of 170 m 2 /g [32]. The large specific surface area of hydrated coal particles and the high concentration of carboxylic and phenolic groups (5-7 mmol/g) are thus likely to be responsible for the strong metal-binding capacity of low-rank coals.…”

Adsorption of Lead (II) and Zinc (II) from Aqueous Solution by Bituminous coal

“…Their large sorption capacity is linked to their high surface area and the presence of a wide spectrum of surface functional groups (carboxyl and phenolic) that enable activated coals to act as efficient adsorbents due to specific and non-specific metal ion-carboxylate and/or phenolate interactions (Martyniuk and Wieckowska 2004). The most common methods used for the activation of coals include heat treatment (Murakami et al 2001) and/or chemical treatments (Verheyen et al 1995;Toles et al 1996;Amarasekera et al 1998;Chingombe et al 2005;Del Mar Gómez-Tamayo et al 2008).…”