Biomass fly ash geopolymer monoliths for effective methylene blue removal from wastewaters


For the first time biomass fly ash geopolymer monoliths were used as adsorbents for the removal of methylene blue from synthetic wastewaters. Highly porous and lightweight fly ash-based geopolymers were produced and then evaluated as methylene blue adsorbents. The geopolymers' porosity strongly affects the dye extraction, a threefold increase (from 5.4 to 15.4 mg/g) being observed when the porosity rises from 40.7 to 80.6%. The maximum uptake reported here (15.4 mg/g) surpasses several other powdered adsorbents, which demonstrates the interesting potential of this innovative adsorbent. Moreover, these monolithic adsorbents can be used directly in packed beds as membranes, this being a major advantage over powdered adsorbents. Furthermore, these adsorbents were successfully regenerated and reused (up to five cycles) without compromising the performances. In fact, enhanced methylene blue uptake (up to 20.5 mg/g) was observed after regeneration. Additionally, an unexplored waste stream was used as raw material which mitigates the waste environmental footprint contributing towards a circular economy. (C) 2017 Elsevier Ltd. All rights reserved.



subject category

Science & Technology - Other Topics; Engineering; Environmental Sciences & Ecology


Novais, RM; Ascensao, G; Tobaldi, DM; Seabra, MP; Labrincha, JA

our authors


This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement.

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