Electrical properties and the surface characteristics of lanthanum oxide/water interface

Roy, S. K.; Sengupta, P. K.

doi:10.1016/0021-9797(88)90083-5

Cited by 9 publications

(1 citation statement)

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“…PZC at pH 10.3 was obtained by mass titration by Subramanian et al [11] PZC obtained by potentiometric tiration and IEP obtained by electroosmosis at pH 9.6 are reported by Roy and Sengupta. [12] IEP at pH 6.7 was found by means of electrophoresis by Taha. [13] IEP at pH 9.5 was found by means of electroosmosis.…”

Section: Introductionmentioning

confidence: 99%

Letter: The IEP of Carbonate-Free Neodymium(III) Oxide

Kosmulski

Próchniak

Rosenholm

2009

Journal of Dispersion Science and Technology

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INTRODUCTIONSeveral metal oxides spontaneously react with atmospheric CO 2 to produce metal carbonates. The particles of these oxides, which have been exposed to atmospheric CO 2 are covered with carbonate layers. A relatively low mass fraction of carbonate may substantially change the surface properties of an oxide particle if it constitutes the external layer of that particle, which is the case for originally carbonate-free metal oxide exposed to atmospheric CO 2 . The presence of carbonate induces a shift in the points of zero charge and isoelectric points (PZC and IEP) of metal oxides to low pH. For example carbonatefree specimens of Y 2 O 3 had substantially higher PZC=IEP than the specimens containing carbonate. [1] Probably similar effects occur for oxides of scandium, lanthanum, and of trivalent lanthanides, which are chemical analogs of yttrium, but the effect of carbonate impurities on the PZC and IEP was mostly ignored in the studies devoted to surface charging of those materials.The availability of thermochemical data of lanthanide carbonates is limited, and the published results show substantial scatter, but the available data indicate that the oxides of lanthanides may spontaneously react with atmospheric CO 2 . For example DG f of Nd 2 (CO 3 ) 3 of À3219 kJmol À1 and of À3116 kJmol À1 is reported in the literature. [2,3] The latter article reports also DG f of NdOHCO 3 of À1476 kJmol À1 . Similar results have been published for other lanthanide carbonates. The above values suggest that DG of the reactions:

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Section: Introductionmentioning

confidence: 99%