Synthesis of porous biomass fly ash-based geopolymer spheres for efficient removal of methylene blue from wastewaters
| Autor: | Rui M. Novais, Robert C. Pullar, Maria Paula Seabra, David M. Tobaldi, João A. Labrincha, João Carvalheiras |
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| Rok vydání: | 2019 |
| Předmět: |
Inorganic polymer
Dye Settore ING-IND/22 - Scienza e Tecnologia dei Materiali 020209 energy Strategy and Management Biomass 02 engineering and technology Geopolymer Industrial and Manufacturing Engineering chemistry.chemical_compound Adsorption 0202 electrical engineering electronic engineering information engineering Porosity 0505 law General Environmental Science Settore CHIM/03 - Chimica Generale e Inorganica Renewable Energy Sustainability and the Environment Chemistry Settore CHIM/07 - Fondamenti Chimici delle Tecnologie 05 social sciences Sorption Building and Construction Waste Fly ash 050501 criminology Sewage treatment Methylene blue Nuclear chemistry |
| Zdroj: | Journal of Cleaner Production. 207:350-362 |
| ISSN: | 0959-6526 |
| Popis: | In this work, and for the first time, fly ash (FA)-based geopolymer (d = 2.6 mm) spheres were used to extract methylene blue from synthetic wastewaters. The influence of sorption time, dye initial concentration and adsorbent amount on the dye removal efficiency and uptake by the porous spheres was evaluated. The adsorbents' recyclability and their dye fixation efficiency were also considered. The initial dye concentration strongly affected the uptake and removal efficiency by the porous bodies, the former rising from 1.1 to 30.1 mg/g when the dye initial concentration jumped from 10 to 250 ppm, and the latter increasing from 82.3% to 94.3% when the dye initial concentration varied from 10 to 125 ppm. Results showed a much faster (24 h) and higher (30.1 mg/g) methylene blue uptake in comparison with the other bulk-type geopolymers reported to date (30 h; 15.4 mg/g). The cumulative methylene blue uptake shown by these innovative spheres (79.7 mg/g) surpasses all other powdered geopolymer adsorbents, being among the highest values ever reported for geopolymers. The adsorbent was successfully regenerated and reused eight times. Regeneration was found to negatively affect the MB uptake, but nevertheless, even after eight regeneration cycles a very high MB removal efficiency (83%) was maintained. The use of these bulk-type waste-based geopolymer adsorbents is a low-cost, more eco-friendly, safer and easier alternative to the use of powdered adsorbents in wastewater treatment systems, since these ∼3 mm spheres may be used directly in packed beds, and were produced using significant amounts of waste material. |
| Databáze: | OpenAIRE |
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