ADSORPTION OF SILICIC ACID ON THORIA-DETERMINED BY INFRARED SPECTROSCOPY. Technical Report No. V

Technical Report · Tue Jun 30 04:00:00 EDT 1959

OSTI ID:4233543

Spaepen, G J; Wimber, R T; Wadsworth, M E

Adsorption isotherms were obtained for silicic acid adsorbed on thoria from aqueous solutions at 16, 49.6, and 71.5 deg C. Typical Langmuir isotherms were obtained from which the equilibrium constants could be calculated. Additional equilibrium constants were obtained by equilibrating in an autoclave from which flash samples wcre removed up to temperatures of 280 deg C. The amount of silica adsorbed was determined from infrared spectra of the adsorbate on the surface of the thoria. It was found that the silicic acid adsorbed with a positive enthalpy and entropy of adsorption. The equilibrium constant for adsorption increased with temperature to a maximum and then decreased above 215 deg C. The abnormal positive enthalpy and large positive entropy have been explained in terms of the adsorption of a silicic acid polymer on the surface of thoria involving the breakup of polymer chains and the splitting-out of water from the surface of thoria. At elevated temperatures the length of the polymer chain breaks down, thereby causing the equilibrium constant to go through a maximum and then diminish. (auth)

• Research Organization: Utah. Univ., Salt Lake City. Inst. of Metals and Explosives Research
• NSA Number: NSA-13-019208
• OSTI ID: 4233543
• Report Number(s): AECU-4299
• Country of Publication: United States
• Language: English

Related Subjects

ADSORPTION
DECOMPOSITION
HIGH TEMPERATURE
INFRARED RADIATION
METALLURGY AND CERAMICS
POLYMERS
PRESSURE VESSELS
SILICIC ACID
SILICON COMPOUNDS
SPECTROSCOPY
SURFACES
THERMODYNAMICS
THORIUM OXIDES