Abstract-Textile effluent is rich in hydrolyzed dyes that need to be removed. This study presents an evaluation of the potential of the enzyme horseradish peroxidase to remove the hydrolyzed dyes Reactive Blue 21 (RB 21) and Reactive Red 195 (RR 195) from cotton fiber and the effluent of the dyeing process. The parameters pH, dye concentration and temperature were evaluated to determine the optimal conditions to remove the dyes. The studies of removal of the dyeing effluent led to an increase of degradation for all tested colors. The use of the enzyme horseradish peroxidase as a biocatalyst can be a viable technological alternative to remove some hydrolyzed dyes.

Foi identificado xenótimo (YPO4) aluvionar em concentrados de bateia colhidos numa campanha de prospecção de terras raras desenvolvida pelo ex-IGM no centro-leste de Portugal. O xenótimo ocorre em grãos sub-rolados de dimensão média ≈ 250 µm e a sua identidade foi confirmada através de difracção de raios X e análises de microssonda electrónica. As concentrações mais significativas foram identificadas em Nisa, S.to António das Areias e Marvão. A geologia regional e o cortejo mineral das amostras sugerem que a proveniência do xenótimo possa estar nos maciços graníticos de Penamacor e Nisa e ainda as Arcoses da Beira Baixa e níveis de cascalheiras Plio-Plistocénicas com intercalações argilo-arenosas. Embora o seu interesse económico seja actualmente limitado, a procura deste mineral pode aumentar como resultado da potencial utilização de ítrio no fabrico de supercondutores estáveis à temperatura ambiente.

Trace amounts of alluvial xenotime (YPO4) were identified in black sands from pan concentrates collected during a rare earth reconnaissance survey, carried by the Instituto Geológico e Mineiro (IGM) in Central Eastern Portugal. The xenotime occurs as sub-rounded grains with an average size of ≈ 250 mm, and its identification was confirmed through XRD methods and EPMA analysis. It is believed that xenotime is more abundant than normally recognized and therefore frequently overlooked. The largest concentrations of this mineral occur in Nisa, S.to António das Areias and Marvão. The regional geology and the accompanying mineral suite suggest xenotime originates from the granitic massifs of Nisa and Penamacor as well as the Beira Baixa Arkoses and levels of Plio-Pleistocene gravels interspersed with sandy clay. Although its economic interest is presently limited, its demand may increase as a result of the potential use of yttrium in the manufacturing of superconductors that are stable at ambient temperature.