Ice-templated geopolymer beads for dye removal

Elettra Papa; Matteo Mor; Annalisa Natali Murri; Elena Landi; Valentina Medri

doi:10.1016/j.jcis.2020.03.104

Ice-templated geopolymer beads for dye removal

J Colloid Interface Sci. 2020 Jul 15:572:364-373. doi: 10.1016/j.jcis.2020.03.104. Epub 2020 Mar 31.

Authors

Elettra Papa¹, Matteo Mor², Annalisa Natali Murri², Elena Landi², Valentina Medri²

Affiliations

¹ National Research Council of Italy, Institute of Science and Technology for Ceramics (CNR-ISTEC), Via Granarolo 64, 48018 Faenza, RA, Italy. Electronic address: elettra.papa@istec.cnr.it.
² National Research Council of Italy, Institute of Science and Technology for Ceramics (CNR-ISTEC), Via Granarolo 64, 48018 Faenza, RA, Italy.

PMID: 32268222
DOI: 10.1016/j.jcis.2020.03.104

Abstract

Geopolymer beads, conceived as alternative low cost adsorbents for wastewater treatment, were shaped by a dripping technique in liquid nitrogen, through an ice-templating process. PEG600 was added as a binder to ease the process, standardizing the beads dimension. The beads were investigated in terms of morphology, microstructure and mechanical strength, following compressive tests by ISO 18591. Functional tests, to verify the adsorption capacity, were conducted using methylene blue (MB) with different concentrations and for different contact time. The removal efficiency was mainly related to the morphology and porosity of the beads, which in turn was directly related to the water content added to the geopolymer slurry. In general, all beads reached an average removal efficiency of 98% after 24 h. However, the best performing beads were able to uptake MB very quickly, attaining a removal efficiency of 76% after only 30 min.

Keywords: Adsorption; Beads; Geopolymer; Ice-templating; Injection-solidification; Wastewater treatment.