Adsorption of acid dye onto activated Algerian clay

In this work, activated clay from Algeria was used as adsorbent for the removal of methyl orange (MO) from aqueous solution, for this, the effects of several parameters such as contact time, adsorbent dose, pH value of aqueous solution and temperature on the adsorption of MO were also studied. The results showed that nearly 30 min of contact time are found to be sufficient for the adsorption to reach equilibrium and the adsorption was favourable at lower pH. The acid dye concentration is measured with UV-visible spectrophotometer at a wavelength of 464 nm. The adsorption capacity of MO found to be 32.57 mg/g. The Pseudo-first-order and pseudo-second-order models were used to fit the experimental data. The adsorption kinetic process was found to follow a pseudo second order model.The Langmuir and Freundlich isotherms models were used to describe adsorption data, the results indicates that Langmuir and Freundlich models provide better correlation of the experimental data. The negative values of ΔG° at different temperatures show that the adsorption process is spontaneous. The values of ΔH and ΔS were found to be 1.04 kJ/mol and 3.35 J/mol.K, respectively. The positive value of ΔH confirms that the adsorption is endothermic and the adsorption process is chemical nature

Impact of potassium on the heats of adsorption of adsorbed CO species on supported Pt particles by using the AEIR method

International audienceThe heats of adsorption at several coverages of the linear and bridged CO species (denoted L and B, respectively) adsorbed on the Pt0 sites of the 2.9 wt% Pt/10% K/Al2O3 catalyst are determined using the Adsorption Equilibrium Infrared spectroscopy method. The addition of K on 2.9% Pt/Al2O3 modifies significantly the adsorption of CO on the Pt particles: (a) the ratio L/B is decreased from 8.4 to 1, (b) a new adsorbed CO species is detected with an IR band at 1763 cm−1, (c) the heats of adsorption of L and B CO species are significantly altered and the positions of their IR bands are shifted. The heats of adsorption of L CO species are decreased: i.e. 206 and 105 kJ/mol at low coverages on Pt/Al2O3 and Pt/K/Al2O3 respectively. Two B CO species denoted B1 and B2, with different heats of adsorption are observed on Pt/K/Al2O3. The heats of adsorption of B2 CO species (major B CO species) are significantly larger than those measured in the absence of K: i.e. 94 and 160 kJ/mol at low coverages on Pt/Al2O3 and Pt/K/Al2O3 respectively, whereas those of B1 CO species (minor species) are similar: 90 kJ/mol at low coverages. These values are consistent with the qualitative High Resolution Electron Energy Loss Spectrometry literature data on Pt(1 1 1) modified by potassium

Mechanistic study of Diesel soot combustion over an AgMnOx catalyst

International @ INGENIERIE+NOG:DBI:CMIInternational audienceNon

Mechanistic study of diesel soot combustion over an AgMnOx catalyst

AIR:INGENIERIE:SURFACES+NOG:BBA:DBI:CM

Mechanistic study of diesel soot combustion over an AgMnOx catalyst

AIR:INGENIERIE:SURFACES+NOG:BBA:DBI:CM

Common Fixed Points of Mappings and Set-Valued Mappings in Symmetric Spaces with Application to Probabilistic Spaces

The main purpose of this paper is to give some common fixed point theorems of mappings and set-valued mappings of a symmetric space with some applications to probabilistic spaces. In order to get these results, we define the concept of E-weak compatibility between set-valued and single-valued mappings of a symmetric space