Additive Manufacturing of Geopolymers Modified with Microalgal Biomass Biofiller from Wastewater Treatment Plants
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Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
2
INSTM—National Interuniversity Consortium of Materials Science and Technology, Via G. Giusti 9, 50121 Firenze, Italy
*
Author to whom correspondence should be addressed.
Materials 2019, 12(7), 1004; https://doi.org/10.3390/ma12071004
Received: 26 February 2019
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Revised: 22 March 2019
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Accepted: 25 March 2019
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Published: 27 March 2019
(This article belongs to the Special Issue Sustainability in Construction and Building Materials)
This paper deals with the additive manufacturing of metakaolin-based geopolymers and with the use of microalgal biomass from wastewater treatment plants as biofiller in this kind of cementitious material. The study was developed following the evolution stages of the material, which was prepared and printed as a soft paste and then hardened thanks to an inorganic polymerization reaction (geopolymerization). Thus, the characterization techniques adopted encompassed rheometry, mechanical tests performed on the hardened material, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and mercury intrusion porosimetry (MIP). Microalgal biomass addition, evaluated in this study at 1, 3 and 5 php with respect to the powder weight, affected both the properties of the fresh and of the hardened material. Regarding the former aspect, biomass reduced the yield stress of the pastes, improving the ease of the extrusion process, but potentially worsening the ability to build structures in height. When hardened, geopolymers containing microalgae showed mechanical properties comparable to the unfilled material and a microstructure characterized by smaller pores. Finally, a printing test was successfully performed with a larger printer to assess the feasibility of producing large-scale structures. Taking into account these results, this study demonstrates the possibility of using microalgal biomass as biofiller in geopolymers for additive manufacturing.
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Keywords:
additive manufacturing; 3D printing; liquid deposition modeling; geopolymers; metakaolin; biofillers; end-of-life materials; microalgae; SaltGae
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MDPI and ACS Style
Agnoli, E.; Ciapponi, R.; Levi, M.; Turri, S. Additive Manufacturing of Geopolymers Modified with Microalgal Biomass Biofiller from Wastewater Treatment Plants. Materials 2019, 12, 1004. https://doi.org/10.3390/ma12071004
AMA Style
Agnoli E, Ciapponi R, Levi M, Turri S. Additive Manufacturing of Geopolymers Modified with Microalgal Biomass Biofiller from Wastewater Treatment Plants. Materials. 2019; 12(7):1004. https://doi.org/10.3390/ma12071004
Chicago/Turabian StyleAgnoli, Emanuele, Riccardo Ciapponi, Marinella Levi, and Stefano Turri. 2019. "Additive Manufacturing of Geopolymers Modified with Microalgal Biomass Biofiller from Wastewater Treatment Plants" Materials 12, no. 7: 1004. https://doi.org/10.3390/ma12071004
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