Université de Neuchâtel

Water adsorption on activated carbons with different degrees of oxidation

Carrasco-Marín, Francisco ; Mueden, Abdelaziz ; Centeno, Teresa A. ; Stoeckli, Fritz ; Moreno-Castilla, Carlos

In: Journal of the Chemical Society, Faraday Transactions, 1997, vol. 93, no. 15, p. 2211-2215

A typical activated carbon, derived from olive stones, has been oxidized to different degrees with (NH4)2S2O8 and analysed by water vapour adsorption, immersion calorimetry, acid–base titration and temperature-programmed desorption of CO2 and CO monitored by mass spectrometry. These techniques led to a coherent description of the surfaces...

Université de Neuchâtel

On the characterization of acidic and basic surface sites on carbons by various techniques

López-Ramón, María Victoria ; Stoeckli, Fritz ; Moreno-Castilla, Carlos ; Carrasco-Marín, Francisco

In: Carbon, 1999, vol. 37, no. 8, p. 1215-1221

Active carbons of different origins have been oxidized with H2O2 and (NH4)2S2O8 and their oxygen surface complexes have been characterized by TPD, classical titration following Boehm's method and by neutralization calorimetry. The net enthalpies of neutralization, determined by immersion calorimetry into NaOH and HCl 2 N lead to...

Université de Neuchâtel

Specific and Nonspecific Interactions between Methanol and Ethanol and Active Carbons

López-Ramón, María Victoria ; Stoeckli, Fritz ; Moreno-Castilla, Carlos ; Carrasco-Marín, Francisco

In: Langmuir, 2000, vol. 16, no. 14, p. 5967–5972

The interaction of methanol and ethanol with active carbons of different origins and containing between 0.81 and 7 mmol g-1 surface oxygen has been examined by immersion calorimetry and by vapor adsorption at 293 K, benzene being the reference. The results obtained by these independent techniques are in excellent agreement. With respect to pure carbons, the surface oxygen leads to...

Université de Neuchâtel

Adsorption of Phenolic Compounds from Aqueous Solutions, by Activated Carbons, Described by the Dubinin−Astakhov Equation

Stoeckli, Fritz ; López-Ramón, María Victoria ; Moreno-Castilla, Carlos

In: Langmuir, 2001, vol. 17, no. 11, p. 3301–3306

It is shown that the adsorption of phenol and 3-chlorophenol from aqueous solutions, by basic active carbons and at an equilibrium solution pH below that of dissociation of the phenols, can be described by an equation of the DRK type with exponent n = 4. The principle of temperature invariance is fulfilled between 283 and 313 K, which means that predictions can be made on the basis of a...