On the L_o/σ Range of the TVFM

Abstract

Adsorption isotherms of nitrogen, carbon dioxide, methanol, dichloromethane, benzene and neopentane were determined on a range of molecular sieve and super-activated carbons with the objective of establishing the range of validity of the Theory of Volume Filling of Micropores (TVFM) in terms of the ratio of pore width to molecular diameter, L o /σ. It is shown that, in the absence of molecular-sieving effects, both the characteristic curve concept and the DR equation are valid over the whole of the micropore range, corresponding to values of L o /σ less than or equal to 5 and to at least a slight enhancement in the characteristic energy, E 0 , of the adsorbent when compared with the corresponding value obtained with non-porous carbon blacks. On the other hand, estimation of the mean micropore width was only possible for values of L o /σ up to ca. 2.3, corresponding to at least a two-fold enhancement in E 0 . Results obtained using N 2 at 77 K showed some significant differences to those obtained with organic adsorptives at higher temperature.

Adsorption of volatile organic compounds onto activated carbon cloths derived from a novel regenerated cellulosic precursor

“…The temperature used for the isotherm determinations did not exert by itself a strong influence on the textural parameters. The E 0 values suggested the existence of a stronger adsorbate-adsorbent interaction in the ACC having narrower pores [32,34]. In the case of ACC 864, the nitrogen volume adsorbed near saturation was on average 10% higher than the total volume obtained by using the organics as adsorbates, likely due to constrictions in some pore entrances.…”

Reactivity and porosity development during pyrolysis and physical activation in CO2 or steam of kraft and hydrolytic lignins

“…Furthermore, very little work has so far been carried out with hydrolytic lignin in comparison to kraft lignins [7]. The study was restricted to physical activation as we have particular interest in materials, namely carbon molecular sieves (CMS), with micropore sizes in the range of 0.4-0.8 nm and which are used for separations involving O 2 , N 2 , CO 2 and CH 4 , for example [39][40][41][42]. It has so far proven difficult to obtain CMS with micropore volumes greater than about 0.2 cm 3 g À1 [43].…”

Utilization of Biomass Waste at Water Treatment

“…Table 1 presents some findings related to using natural adsorbents, without any treatment, in eliminating MB from the aqueous phase. Enset midrib leaf 35.5 5.66 1 [9] Sugarcane bagasse 9.4 24 [18] Chlorella vulgaris microalgae 275 --72 [20] Corn husk 30.3 6.2 0.25 [21] Ficus carica bast treated with H 2 SO 4 55.56 7.8 1.33 [22] Natural adsorbents (review) ------ [12,13] Potato peel 48.7 --1.0 [23] Date palm leaves 43.1 6.5 2.7 [16] Modified zeolites 133.1 [24] Hylocereus undatus (dragon fruit peels) 192.31 5.6 0.15-2 [25] MB has become increasingly important in the field of water treatment because it is environmentally persistent, toxic, carcinogenic, and mutagenic [26][27][28][29][30][31][32][33][34][35][36]. These effects are quite similar to the side effects caused by the majority of organic pollutants present in water used for household activities by rural populations in developed countries.…”