Determination of noble metals in geological materials by radiochemical neutron-activation analysis

Ahmad, I.; Ahmad, Shujaat; Morris, D.F.C.

doi:10.1039/an9770200017

Cited by 37 publications

(5 citation statements)

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“…The determined mineralogical constituents are reported in Table 1, which reveals that the LM is mainly composed of hydrous oxides of iron bearing minerals. The elemental composition of the LM was characterized by using instrumental neutron activation analysis (INAA) [29,30], and the results are shown in Table 2.…”

Section: Characterization Of Adsorbentmentioning

confidence: 99%

Zirconium decontamination from aqueous media using lateritic minerals

Khalid¹,

Daud²,

Ahmad³

2005

Radiochimica Acta

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The sorption behavior of zirconium on minerals from a lateritic weathering has been carried out to evaluate its potential for the decontamination of zirconium ions from aqueous solutions. Various physico-chemical parameters such as selection of appropriate electrolyte, equilibration time, amount of adsorbent, concentration of adsorbate, effect of diverse ions and temperature were studied in order to simulate the best conditions under which this material can be used as an adsorbent, employing batch method and radiotracer technique. Maximum adsorption was observed at 0.005 mol L −1 acid solutions (HNO 3 , HCl, H 2 SO 4 and HClO 4 ) using 0.3 g of adsorbent for 1.499 × 10 −4 mol L −1 zirconium concentration in five minutes equilibration time. Studies show that the adsorption of zirconium decreases with the increase in the concentrations of all the acids. The adsorption data follows the Freundlich isotherm over the range of 7.5 × 10 −5 to 3.0 × 10 −3 mol L −1 zirconium concentration. The characteristic Freundlich constants i.e. 1/n = 0.55 ± 0.03 and K = 1.36 × 10 −3 ± 7.0 × 10 −5 mol g −1 have been computed for the sorption system. The sorption mean free energy from the Dubinin-Radushkevich isotherm is 11.2 ± 0.4 kJ mol −1 indicating ion-exchange mechanism of chemisorption. The uptake of zirconium increases with the rise in temperature (283-323 K). Thermodynamic quantities i.e. ∆G, ∆S and ∆H have also been calculated for the system. The sorption process was found endothermic.

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Section: Characterization Of Adsorbentmentioning

confidence: 99%

Zirconium decontamination from aqueous media using lateritic minerals

Khalid¹,

Daud²,

Ahmad³

2005

Radiochimica Acta

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“…The determined mineralogical constituents have been reported in Table 1, which revealed that the MM is mainly composed of hydrous oxides of iron bearing minerals. The chemical composition of the MM was established by using Instrumental Neutron Activation Analysis (INAA) [29,30] and the resuhs are given in Table 2. …”

Section: Characterisation Of Adsorbentmentioning

confidence: 99%

Adsorption Studies of Radioactive Silver Using Mineral Mixture

1999

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The adsorption behavior of mineral mixture for silver ions from aqueous solutions has been carried out as a function of appropriate electrolyte, equilibration time, amount of adsorbent, concentration of adsorbate, effect of diverse ions and temperature in Order to simulate the best conditions in which this material can be used as an adsorbent. The radiotracer technique was employed to determine the distribution of silver ("°"Ag) using a batch method. Maximum adsorption was observed at 0.005 mol L ' acid solutions (HNO,, H2SO4 and HCIO4) using 0.3 g of adsorbent for 1.29 X10"" mol L"' silver concentration in five minutes equilibration time. Studies show that the adsorption decreases with an increase in the concentrations of all the acids. The adsorption data follows the Freundlich isotherm over the ränge of 2.0 X IQ-' to 2.0X10"'mol L"' silver concentration. The characteristic Freundlich constants, i.e. l/n = 0.64 ±0.02 and K = 1.91 ±0.07 m mol g have been computed for the Sorption system. The uptake of silver increases with the rise in temperature (278-323 K).

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“…It has been demonstrated that errors due to self-shielding differences for neutrons between common rocks or laterite [19] and dilute aqueous solutions used as controls are not significant. However, there are geological materials, e. g., lepidolite, colemanite, pyrolusite, smaltite, monazite, which contain as major constituents some elements with high neutron-absorption cross-sections; in such cases preparation of comparators by small Standard additions of Ge and Sn to analysis samples is probably the best answer [20].…”

Section: Discussionmentioning

confidence: 96%