Rare earth elements, i.e., lanthanides, are important components of many recently developed technology applications. However, their increasing use in the industrial sector, medicine, and agriculture over the last few decades has provided them with the title of “new pollutants”. Different methods are now applied for the removal of various pollutants from wastewaters, whereby the emphasis is placed on adsorption due to its simplicity, high efficiency, and low cost. In the present study, geopolymers prepared from coal ash were examined regarding their capacity for the adsorption of lanthanides from model solutions. The obtained results indicate the efficient removal of lanthanides by prepared geopolymers, depicting them as effective adsorbents for this group of elements.
Monazite and xenotime are major ore minerals for rare earth elements (REE), Y, and actinides, a powerful tool for radiometric dating and indicators of the geological genesis of the parent rock. In this contribution, we present results of microanalysis of monazite and xenotime mineral grains found in heavy mineral sand fraction from Drava river. Investigated grains of monazite(-Ce) were found to be exhibiting varying concentrations of Th, indicating mixed hydrothermal (or greenschist-amphibolite grade) and igneous origin. Monazite was found to be isomorphically replaced by cheralite (CaTh(PO 4 ) 2 ) and subordinately by huttonite (ThSiO 4 ), forming monazitecheralite and monazite-huttonite solid solution. Chemical composition and the degree of isomorphic replacement of monazite grains are indicating their source from rocks of Eclogite belt and Granatspitz massif in Tauern Window, Austria. On the other hand xenotime(-Y) shows consistent concentrations of Y while concentrations of associated heavy rare earth elements (HREE) vary, indicating the origin of mixed affinities. IzvlečekMinerala monazit in ksenotim sta pomemben vir redkih zemelj, itrija in aktinidov. Lahko ju uporabimo tudi kot orodje za radiometrično datiranje (geokronologijo), ter kot indikator geneze matične kamnine. V prispevku predstavljamo rezultate mikroanalize zrn monacita in ksenotima zaznanih v frakciji težkih peskov reke Drave. Cerijev monacit ima spremenljive vsebnosti Th, kar kaže na njegov hidrotermalni izvor ali izvor iz metamorfnih (od faciesa zelenega skrilavca do amfibolitnega faciesa) in magmatskih kamnin. Rezultati mikroanalize monacita kažejo izomorfno nadomeščanje s ceralitom (CaTh(PO 4 ) 2 ) in v manjši meri s huttonitom (ThSiO 4 ), pri čemer tvorijo trdno raztopino. Kemijska sestava in stopnja izomorfnega nadomeščanja monacitnih zrn nakazujejo njihov izvor iz kamnin Eklogitnega pasu in masiva Granatspitz v Visokih Turah v Avstriji. V ksenotimu je najbolj zastopan element Y, ki ima v vseh zrnih enakomerne vsebnosti, medtem ko se vsebnosti težkih redkih zemelj (HREE) spreminjajo, kar kaže na izvor iz različnih geoloških okolij.
IZVLEČEK Paleogenski morski ježki iz osrednjega dela zahodne SlovenijeV prispevku so obravnavani morski ježki iz paleogenskih skladov osrednjega dela zahodne Slovenije. Njihova šte-vilna najdišča so v Goriških brdih, na širšem območju Vipavske doline, v Braniški dolini in na Vremščici. Obravnavani so izključno nepravilni morski ježki, primerki pravilnih niso najdeni. Ugotovljeni mikrofosili v najdiščih kažejo na njihovo spodnjeeocensko -cuisijsko starost. Največ primerkov je iz družin reda Spatangoida L. Agassiz, 1840.Ključne besede: morski ježki, paleogen, eocen, Goriška brda, Vipavska dolina, Braniška dolina, Vremščica, Slovenija ABSTRACT Paleogene sea urchins from central part of west SloveniaThe contribution deals with sea urchins in Paleogene beds of central western Slovenia. Their numerous localities occur at Goriška brda, in wider environs of Vipava river valley, in Branik valley and on Mt. Vremščica. Studied were exclusively the irregular sea urchins, since no regular forms were found. Microfossils found at localities indicate the Lower Eocene -Cuisian age. The most frequent specimens belong to families of order Spatangoida L. Agassiz, 1840.
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