Author(s):
Bernardo, Maria ; Lapa, Nuno ; Pinto, Filomena ; Nogueira, Miguel ; Matos, Inês ; Ventura, Márcia ; Ferraria, Ana Maria ; Rego, Ana Maria Botelho do ; Fonseca, Isabel Maria
Date: 2023
Persistent ID: http://hdl.handle.net/10362/153088
Origin: Repositório Institucional da UNL
Project/scholarship:
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F50006%2F2020/PT;
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDP%2F50006%2F2020/PT;
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F04565%2F2020/PT;
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDP%2F04565%2F2020/PT;
Subject(s): Spent Tire Rubber; Chars; Adsorption; Lead; Tungsten; SDG 8 - Decent Work and Economic Growth; SDG 12 - Responsible Consumption and Production
Description
Open access funding provided by FCT|FCCN (b-on). This work was funded by (a) Valorpneu S.A. through the INOV.AÇÃO 2018 Award; Associate Laboratory i4HB (LA/P/0140/2020); Maria Bernardo thanks FCT (Fundação para a Ciência e Tecnologia) for funding through program DL 57/2016 – Norma transitória. A.M. Ferraria thanks Instituto Superior Técnico for Scientific Employment contract IST-ID/131/2018. This work was also financially supported by GREENERING COST Action CA18224.
Spent tire rubber-derived chars and their corresponding H3PO4 and CO2-activated chars were used as adsorbents in the recovery of Pb(II) ion and (W(VI)) oxyanion from synthetic solutions. The developed chars (both raw and activated) were thoroughly characterized to have insight about their textural and surface chemistry properties. H3PO4-activated chars presented lower surface areas than the raw chars and an acidic surface chemistry which affected the performance of these samples as they showed the lowest removals of the metallic ions. On the other hand, CO2-activated chars presented increased surface areas and increased mineral content compared to the raw chars, having presented higher uptake capacities for both Pb(II) (103–116 mg/g) and W(VI) (27–31 mg/g) ions. Cation exchange with Ca, Mg and Zn ions was appointed as a mechanism for Pb removal, as well as surface precipitation in the form of hydrocerussite (Pb3(CO3)2(OH)2). W(VI) adsorption might have been ruled by strong electrostatic attractions between the negatively charged tungstate species and the highly positively charged carbons’ surface. The results shown in this work allow concluding that the valorisation of spent tire rubber through pyrolysis and the subsequent activation of the obtained chars is an alternative and a feasible option to generate adsorbent materials with a high uptake capacity of critical metallic elements.
