Browsing by Subject "Sodium chlorite"

Now showing 1 - 3 of 3

Open Access
Radiochemical study of Co2+ sorption on chlorite and kaolinite
(Akademiai Kiado Rt., 1999) Shahwan, T.; Erten, H. N.
In this work, the sorption behavior of Co(II) ions on natural chlorite and kaolinite as a function of time, concentration and temperature was studied. 60Co radiotracer method and the batch technique were used. The kinetic results indicated that about one day of contact time was enough to achieve equilibrium. The sorption process was described by Freundlich type isotherms. Sorption of Co(II) ions on both clays was found to be endothermic with ΔH(o) (kJ/mol) and ΔS(o) (kJ/mol·K) being 33 and 0.14 for kaolinite and 17 and 0.102 for chlorite, respectively. The magnitudes of the corresponding ΔG(o) values suggest that sorption occur mainly via an ion exchange mechanism on both clays.
Open Access
Surface spectroscopic studies of Cs+, and Ba2+ sorption on chlorite-illite mixed clay
(De Gruyter Oldenbourg, 2000) Shahwan, T.; Sayan, S.; Erten, H. N.; Black, L.; Hallam, K. R.; Allen, G. C.
The sorption behavior of Cs+, and Ba2+ on natural clay was investigated using ToF-SIMS, XPS, and XRD. The natural clay was composed mainly of chlorite and illite in addition to quartz and calcite. Depth profiling up to 70 Å was performed at 10 Å steps utilizing ToF-SIMS to study the amount of sorbed Cs+ and Ba2+ as a function of depth in the clay matrix. The results suggest that Cs+ and Ba2+ ions were sorbed primarily by ion exchange coupled with hydrolytic sorption. According to ToF-SIMS and XPS results, the total sorbed amount of Ba2+ was larger than that of Cs+. Quantitative determination of the primary cations within the analyzed clay before and after sorption indicated that for Ba2+ sorption, Ca2+, Mg2+ and for Cs+ sorption Ca2+, K+ were the major exchanging ions. The XRD spectra of Ba-sorbed clay contained new peaks that were identified as BaCO3.
Open Access
Thermodynamic parameters of Cs+ sorption on natural clays
(Akademiai Kiado Rt., 2002) Shahwan, T.; Erten, H. N.
The sorption behavior of Cs+ on kaolinite, chlorite-illite, and bentonite clays as a function of time, cation concentration, and temperature was studied using the radiotracer method. Sorption data were well represented by Freundlich and Dubinin-Radushkevich type isotherms. Bentonite was found to have the highest sorption capacity and the highest exchange affinity to Cs+. In all three cases Cs+ sorption was found to be exothermic with ΔH° (kJ/mol) -13, -8, -19 and ΔS° (J/mol·K) -15, 31, and -3 for kaolinite, chlorite-illite, and bentonite, respectively. Negative ΔG° values were obtained in all cases, indicating the spontaneity of sorption. The magnitudes of ΔG° suggest that ion exchange is the primary sorption mechanism.