Biomass fly ash geopolymer monoliths for effective methylene blue removal from wastewaters. (10th January 2018)

• Record Type: Journal Article
• Authors: Novais, Rui M.; Ascensão, Guilherme; Tobaldi, David M.; Seabra, Maria P.; Labrincha, João A.
• Is Part Of: Journal of cleaner production. Volume 171(2018)
• Page Start: 783
• Page End: 794
• Publication Date: 2018-01-10
• Subjects: Inorganic polymer -- Porosity -- Adsorption -- Waste -- Dye; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2017.10.078
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: 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. Graphical abstract: Highlights: Novel porous monolithic adsorbents for methylene blue extraction were developed. The geopolymers were produced using 66.6 wt% biomass fly ash (unexplored waste). Methylene blue uptake by the monolithic bodies up to 20.5 mg/g was observed. The removal efficiency can be controlled by pores' volume and connectivity. Adsorbents can be used in packed beds, regenerated and reused (at least 5 times).