Potentiometric Studies on Sulfato Complex of Aluminium(III) in Aqueous Solution at Elevated Temperatures

Abstract

Equilibria in aluminium sulfate solutions with a 1 mol kg−1 KCl medium and low pH range have been investigated by means of acidity measurements with a hydrogen ion concentration cell from 25 to 125 °C. The results were treated with a nonlinear least squares computer program to analyze the equilibrium constants for aluminium complexes by using a single parameter type of Debye–Hückel equation. The log(K/mol−1 kg) values of the formation constant for the reaction, Al3++SO42−\ightleftarrows[AlSO4]+ varied from 3.35 at 25 °C to 5.34 at 125 °C and were formulated as a function of temperature. The standard enthalpy and entropy of the complex formation computed from the variation of the formation constant with temperature are presented over the experimental temperature range. The species [Al(SO4)2]− was not detected under the present conditions.

Ion association and hydration in 3:2 electrolyte solutions by dielectric spectroscopy: Aluminum sulfate

“…It may be noteworthy that a similar result was obtained by Xiao et al (2002). The standard state (infinite dilution) value of the overall association constant so obtained, log K 0 A ¼ 3:56 AE 0:02 (Table 4), lies within the wide range of literature results (ignoring outliers as discussed above): log K 0 A ¼ 3:2 (Behr andWendt, 1962), 3.3 (Kalidas et al, 1971), 3.35 (Matsushima et al, 1988), 3.73 (Nishide and Tsuchiya, 1965), 3.84 (Xiao et al, 2002). A mean value of K 3 = 0.2 ± 0.05 was reported from pressure-jump relaxation experiments in dilute solutions (Kalidas et al, 1971), which is somewhat smaller than the present DRS result ðK 0 3 ¼ 0:6 AE 0:2 at I = 0) but still agrees within the stated error limits.…”

“…Ion association in aluminum sulfate solutions has been studied by potentiometry using various electrodes (Sharma and Prasad, 1970;Matsushima et al, 1988;Ridley et al, 1999;Xiao et al, 2002), conductivity (Nishide and Tsuchiya, 1965), solubility (Ridley et al, 1999), calorimetry (Lo et al, 1982), ultrasonic absorption (Bonsen et al, 1978;Kaatze et al, 1999), stopped-flow (Knoche and Ló pez-Quintela, 1983), and pressure/temperature jump (Miceli and Stuehr, 1968;Kalidas et al, 1971) methods. Spectroscopic techniques such as NMR (Akitt et al, 1969(Akitt et al, , 1972(Akitt et al, , 1985Jin and Ichikawa, 1988;Akitt and Howarth, 1989), Raman Schö nherr, 1989, 1991a,b;Rudolph and Mason, 2001) and UV-vis (Kryzhanovskii et al, 1971;McIntyre et al, 1982) have also been employed.…”

Effect of Sulfate on the Release Rate of Al3+ from Gibbsite in Low-Temperature Acidic Waters

“…Although the aluminum concentration was not measured in the original starting solutions, the concentration of Al measured in a second batch of solutions prepared from the same stock solutions were 10 -7. 13 and less than 10 -7.7 m for the H2SO4 and HCl solutions, respectively. The gibbsite was from the same batch as that used in the earlier studies (6,7).…”

“…Sodium sulfate ion pairs are weak (10) and comprise less than 1% of the total sulfate species. Aluminum sulfate complexes are significant (11)(12)(13)(14)(15)(16)(17), and form by the following reaction:…”

Electrochemical techniques for monitoring and controlling corrosion in water-cooled nuclear reactor systems

“…Various versions of the high temperature aqueous hydrogen concentration cell were subsequently developed by Mesmer et al [9][10][11][12][13], Palmer and/or Wesolowski and co-workers [14][15][16][17][18][19][20] and Macdonald et al [21][22][23]. Results using similar cells have also been reported by Shoesmith and Woon [24], Giasson and Tewari [25], Matsushima et al [26], and Bilal and Mueller [27].…”