Effects of nickel(II) oxide on the thermal decomposition of alkali persulfates

Barbooti, Mahmood M.; Jasim, Fadhil; Tobia, S. K.

doi:10.1016/0040-6031(77)85022-3

Cited by 18 publications

(5 citation statements)

References 8 publications

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“…Other authors observed the α−β transformation of K 2 SO 4 at 592 • C or 612 • C, respectively [6,7], but these investigations were performed with mixtures instead of pure K 2 SO 4 . Electrical conductivity measurements on single crystals have been carried out by Choi et al [8], the transition temperature range extends to 3 K and transition occurs at 586.9 • C on heating and 581.5 • C on cooling, with a thermal hysteresis of 5.4 K. Chen et al performed electrical complex impedance measurements on K 2 SO 4 single crystals [9].…”

Section: Introductionmentioning

confidence: 99%

The solid state phase transformation of potassium sulfate

Anooz

Bertram

Klimm

2007

Solid State Communications

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Potassium sulfate single crystals that are grown from aqueous solutions lose upon the first heating up to 1% of mass that is assumed to be water. This mass loss occurs in the vicinity of the PT from orthorhombic to hexagonal K2SO4. Only in the first heating run of K2SO4 that has not yet released water, pretransitional thermal effects can be observed in the DTA curve. If K2SO4 crystals are grown from solutions containing 4 wt.% Cd, Cu, or Fe, only Cu or Fe can be incorporated significantly with concentrations of several 0.1%. The phase transformation temperature measured for such solid solutions depends on the heating rate. For pure K2SO4, the phase transformation temperature is independent on heating rate 581.3 deg. C and the enthalpy of transformation is (5.8+/-0.2) kJ/mol.Comment: 11 pages, 6 figures, 1 tabl

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Section: Introductionmentioning

confidence: 99%

The solid state phase transformation of potassium sulfate

Anooz

Bertram

Klimm

2007

Solid State Communications

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“…Several investigators have used TG, DTG and DTA to study the non-isothermal (dynamic) decompositions of pure Na.,S2Os and K2S2Os and the decompositions catalyzed by metal oxides such as CuO, TiO2, Zn [1][2][3][4][5], oxides with a corundum structure such as A1203, Cr203 and F%Oa, and oxides with a cubic structure such as CdO [6], to establish their catalytic effects on the decomposition and concluded that these effects increased with the p-type semiconductor characters of the catalyst, thereby supporting previous findings [6].…”

mentioning

confidence: 54%

Thermal and x-ray studies of binary rare earth sesquioxides — Alkali metal persulfate systems

Jasim

Idan

1981

Journal of Thermal Analysis

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Three binary systems, each consisting of mixtures of different molar ratios of a rare earth (4] metal) sesquioxide and sodium or potassium persulfate (peroxodisulfate) have been investigated under static (air) atmospheres using a derivatograph. For each system (RzO a --MeSzOs, where R is Sin, Gd, or Dy, and M is K or Na), the molar ratios that represent stoichiometric reactions were fixed. Calculations were based on data obtained from T, TG, DTG and DTA curves. Intermediate and final products were mainly identified by X-ray diffractometry. Double salts of Sm, Gd, and Dy were thermally prepared by solid-state reactions. It was found that one such double salt KDy(SO4)e, forms a eutectic mixture with K2SO a and also that both Gd and Dy sesquioxides behave as p-type semiconductors and therefore exhibit catalytic activities towards the thermal decomposition of persulfates and pyrosulfates. OptimaI catalysis was obtained with molar ratios of 1 : 3. The activities increased as the ionic radii of these metals decrease: Sm, Gd, Dy.Several investigators have used TG, DTG and DTA to study the non-isothermal (dynamic) decompositions of pure Na.,S2Os and K2S2Os and the decompositions catalyzed by metal oxides such as CuO, TiO2, Zn [1-5], oxides with a corundum structure such as A1203, Cr203 and F%Oa, and oxides with a cubic structure such as CdO [6], to establish their catalytic effects on the decomposition and concluded that these effects increased with the p-type semiconductor characters of the catalyst, thereby supporting previous findings [6].It was found that some of the rare earth sesquioxides act as semiconductors at high temperatures. For instance, both Gd2Oa and Dy~O3 exhibit p-type semiconductor activities at pressures of 10 -9"~ and 10 -11'3 atm and at temperatures of 727-1177 ~ and 727-t377 ~ respectively [8]. Furthermore, it has been shown [7,9] that Sm203, Gd2Oa and Dy2Oz exert catalytic effects by lowering the thermal decomposition temperatures of lithium perchlorate and lithium carbonate.A thermogravimetric study of the thermal decomposition of formic acid over lanthanide oxides such as Sm2Oa and Dy2Oa revealed that the decomposition occurs at 300-400 ~ via a lanthanide formate intermediate, which transformed to an oxycarbonate and then cracked to liberate COz, with reformation of the lanthanide oxide [10].The present paper deals with the influences of the three sesquioxides on the decompositions of the peroxodisulfates of sodium and potassium and their

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“…Hence each S 2 O 8 2anion resides on the surface in such a manner that each tetrahedral moiety is linked to the surface via two oxygen atoms, thereby exposing a terminal S=O group and bridging to the second tetrahedron through the remaining oxygen atom. This may be correlated with the appearance of a shoulder in the IR spectrum at 920 cm -1 since it has been reported that such bridging is responsible for a band at 910 cm -1 in the IR spectrum of tetrasulphatotitanium(IV) ( Barbooti et al 1977).…”

Section: Persulphated Samplesmentioning

confidence: 69%

Physicochemical and Textural Characterization of Perchlorated and Persulphated Titania

Moussa

2000

Adsorption Science & Technology

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Samples of perchlorated and persulphated rutile were obtained by soaking the solid in aqueous solutions of HClO 4 and (NH 4 ) 2 S 2 O 8 of 0.05 M, 0.10 M and 0.20 M concentration and characterized by XRD and FT-IR spectroscopic studies and by acidity and textural assessment. The XRD results indicated that the interaction of titania with the loaded anions, i.e. ClO -4 and S 2 O 8 2-, resulted in an increase in the volume of the unit cell mainly due to an increase in the c 0 value of the tetragonal crystal lattice. The IR spectra showed that both ClO -4 and S 2 O 8 2-anions were linked to the surface via bidentate bridging. Such behaviour created strong acidic sites as probed by pyridine (pK a = 5.3) whose number increased with increasing anion loading. The acidity of the perchlorated samples was higher than that of the persulphated materials. Textural analysis showed that the specific surface areas of both samples responded to the loading process to a lower extent than the total pore volume and correspondingly to the average hydraulic radius, since the latter changed in relation to the total pore volume.

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Effects of nickel(II) oxide on the thermal decomposition of alkali persulfates

Cited by 18 publications

References 8 publications

The solid state phase transformation of potassium sulfate

The solid state phase transformation of potassium sulfate

Thermal and x-ray studies of binary rare earth sesquioxides — Alkali metal persulfate systems

Physicochemical and Textural Characterization of Perchlorated and Persulphated Titania

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