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Generically Dependent Continuant
RDF description of Alkaline reactivity of arsenical natrojarosite - http://orbis.uaslp.mx/vivo/individual/scopus7529
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Jarosites are compounds that can undergo substitutions with several elements of environmental importance (such as As5%2b) during precipitation. Arsenic integrated in the structure could influence the solubility of the jarosite, potentially stabilizing the structure under a wide range of conditions that are tolerated by pure jarosite. Alkaline reactivity is characterized by the removal of sulfate and sodium ions from the lattice and by the formation of a gel consisting of iron hydroxides with adsorbed arsenate. The decomposition curves show an induction period, followed by a conversion period. The induction period is independent from the particle size and decreases exponentially as the temperature increases. The conversion period is characterized by the formation of a hydroxide halo around an unreacted arsenical natrojarosite core. The kinetic data are consistent with the chemical control of the process. The expression obtained in NaOH medium for [OH-] concentrations ranging from 3.84 × 10-3 to 1.08 × 10 -1 mol L-1 is the following: r0/v̄[1 - (1 - x)1/3] = 3.11 × 109 exp(-57.110/RT) [OH -]0.7t. The expression in Ca(OH)2 medium for [OH-] concentrations ranging from 2.21 × 10-2 to 6.98 × 10-2 mol L-1 is the following: r 0/v̄[1 - (1 - x)1/3] = 9.22 × 1011 exp(-48.610/RT) [OH-]1.51t. © 2011 Sociedade Brasileira de Química.
Alkaline reactivity of arsenical natrojarosite
Amorphous; Arsenate; Arsenical natrojarosite; Decomposition; Kinetics; Reactivity
Jarosites are compounds that can undergo substitutions with several elements of environmental importance (such as As5 ) during precipitation. Arsenic integrated in the structure could influence the solubility of the jarosite, potentially stabilizing the structure under a wide range of conditions that are tolerated by pure jarosite. Alkaline reactivity is characterized by the removal of sulfate and sodium ions from the lattice and by the formation of a gel consisting of iron hydroxides with adsorbed arsenate. The decomposition curves show an induction period, followed by a conversion period. The induction period is independent from the particle size and decreases exponentially as the temperature increases. The conversion period is characterized by the formation of a hydroxide halo around an unreacted arsenical natrojarosite core. The kinetic data are consistent with the chemical control of the process. The expression obtained in NaOH medium for [OH-] concentrations ranging from 3.84 × 10-3 to 1.08 × 10 -1 mol L-1 is the following: r0/v̄[1 - (1 - x)1/3] = 3.11 × 109 exp(-57.110/RT) [OH -]0.7t. The expression in Ca(OH)2 medium for [OH-] concentrations ranging from 2.21 × 10-2 to 6.98 × 10-2 mol L-1 is the following: r 0/v̄[1 - (1 - x)1/3] = 9.22 × 1011 exp(-48.610/RT) [OH-]1.51t. © 2011 Sociedade Brasileira de Química.
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Journal of the Brazilian Chemical Society
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