title: Novel porous fly-ash containing geopolymer monoliths for lead adsorption from wastewaters.
abstract: In this study novel porous biomass fly ash-containing geopolymer monoliths were produced using a simple and flexible procedure. Geopolymers exhibiting distinct total porosities (ranging from 41.0 to 78.4%) and low apparent density (between 1.21 and 0.44g/cm(3)) were fabricated. Afterwards, the possibility of using these innovative materials as lead adsorbents under distinct conditions was evaluated. Results demonstrate that the geopolymers' porosity and the pH of the ion solution strongly affect the lead adsorption capacity. Lead adsorption by the geopolymer monoliths ranged between 0.95 and 6.34mglead/ggeopolymer. More porous geopolymers presented better lead removal efficiency, while higher pH in the solution reduced their removal ability, since metal precipitation is enhanced. These novel geopolymeric monoliths can be used in packed beds that are easily collected when exhausted, which is a major advantage in comparison with the use of powdered adsorbents. Furthermore, their production encompasses the reuse of biomass fly-ash, mitigating the environmental impact associated with this waste disposal, while decreasing the adsorbents production costs.
authors.affiliation: Department of Materials and Ceramic Engineering/CICECO- Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal. Electronic address: ruimnovais@ua.pt.
authors.forename: Rui M
authors.initials: RM
authors.lastname: Novais
authors.affiliation: Department of Materials and Ceramic Engineering/CICECO- Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: L H
authors.initials: LH
authors.lastname: Buruberri
authors.affiliation: Department of Materials and Ceramic Engineering/CICECO- Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: M P
authors.initials: MP
authors.lastname: Seabra
authors.affiliation: Department of Materials and Ceramic Engineering/CICECO- Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: J A
authors.initials: JA
authors.lastname: Labrincha
keywords: Biomass fly ash; Geopolymers; Lead adsorption; Monoliths; Porosity