Adsorption of sulphuric acid on smectite from acidic aqueous solutions

Abstract

The adsorption of sulphuric acid on smectite from acidic aqueous solutions was studied. The amounts of cations dissolved in each equilibrium solution were determined by chemical analysis. Simultaneously, the original smectite and the smectite after each test were characterized by infrared, X-ray diffraction and swelling index. The results obtained permitted us to determine that the substitutions of the exchange cations and the chemical attack occurred at very different acid concentrations and treatment times. It was established that during the acid treatment of the smectite, a progressive damage of its crystalline structure was produced. Finally, the influences of the substitution of exchange cations and of the chemical attack in the swelling index were determined.

Spectral Properties of Anomalous X-ray Pulsars

“…The origin of this high-energy tail is unexplained very well at present. However, this high-energy tail could be due to thermal Comptonization by a hot coronal plasma, or it could be due to non-thermal emission (Tavani & Liang 1996). Based on the energetics of particle acceleration and cooling near the Alfven radius, Böttcher & Liang (2001) simulated the thermal-nonthermal radiation from a neutron star with both a weakly magnetized (∼ 10 9 G) magnetospheric accretion shell and a normal magnetic case (∼ 10 12 G).…”

Effect of the Acid Treatment of Montmorillonite Clay in the Oleic Acid Esterification Reaction

“…The activation force and the number of acidic sites increase with the acid treatment, however, in excess, decreases the catalytic activity of clays because of the impairment of the octahedral layers. According to the literature 21 , the acid attack on clay minerals such, as montmorillonite, with a solution of high concentration causes leaching of ions located in sites octahedral responsible for the stability of the clay mineral, collapsing the structure. The chemical attack of the mineral acids on clay is initially by adsorption of the acid on the surface of the solid leading to replacement of exchangeable cations by protons, and then the adsorbed protons diffuse into the lamella, where the chemical reaction occurs.…”