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Browsing by Author "Gago, Sandra"

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  • Desulfurization process conciliating heterogeneous oxidation and liquid extraction: Organic solvent or centrifugation/water?
    Publication . Ribeiro, Susana O.; Nogueira, Lucie S.; Gago, Sandra; Almeida, Pedro L.; Corvo, Marta C.; De Castro, Baltazar; Granadeiro, Carlos; Balula, Salete
    The present work presents a strategic oxidative desulfurization system able to efficiently operate under sustainable conditions, i.e. using an eco-friendly oxidant and without the need of extractive organic solvents. The catalytic performance of Eu(PW11O39)2@aptesSBA-15 was evaluated for the oxidative desulfurization of a multicomponent model diesel using a solvent-free or biphasic systems. The results reveal its remarkable desulfurization performance achieving complete desulfurization after just 2 h of reaction. Moreover, the composite has shown a high recycling ability without loss of catalytic activity for ten consecutive ODS cycles. Interestingly, under solvent-free conditions it was possible to maintain the desulfurization efficiency of the biphasic system while being able to avoid the use of harmful organic solvents. In this case, a successful extraction of oxidized sulfur compounds was found conciliating centrifugation and water as extraction solvent. Therefore, this work reports an important step towards the development of novel eco-sustainable desulfurization systems with high industrial interest.
    2017-07-25Journal article Restricted access Show more
  • A novel red emitting material based on polyoxometalate@periodic mesoporous organosilica
    Publication . Granadeiro, Carlos; Ribeiro, Susana; Kaczmarek, Anna M.; Cunha-Silva, Luis; Almeida, Pedro L.; Gago, Sandra; Van Deun, Rik; De Castro, Baltazar; Balula, Salete
    The first lanthanopolyoxometalate-supported bifunctional periodic mesoporous organosilica (BPMO) composite is here reported. The incorporation of decatunsgstoeuropate anions ([Eu(W5O18)(2)](9-)) within the porous channels of an ethylene-bridged TIVIAPS-functionalized BPMO produced a luminescent material exhibiting a strong red emission under UV irradiation. Photoluminescence studies showed an efficient energy transfer process to the lanthanide emitting center in the material (antenna effect). A significant change in the coordination environment of Eu3+ ions was observed after its incorporation into the TMAPS-functionalized material. The possible reason for this is discussed within the paper.
    2016-11Journal article Restricted access Show more