In-depth investigation of the long-term strength and leaching behaviour of inorganic polymer mortars containing green liquor dregs

Novais, Rui M.; Carvalheiras, João; Senff, L.; Seabra, M.P.; Pullar, Robert C.; Labrincha, J.A.

doi:10.1016/j.jclepro.2019.02.170

Cited by 15 publications

(9 citation statements)

References 44 publications

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“…The alkali-activated foams were produced using a composition developed by the authors [18,19] containing a 70/30 fly ash and metakaolin blend activated with a 75/25 sodium silicate/sodium hydroxide solution (in weight). The molarity of the sodium hydroxide solution (8 M) and the foaming agent amount (0.1 wt.% aluminium plus 0.05 wt.% surfactant) were selected following our previous findings [20] and considering both technical and economic reasons.…”

Section: Synthesis Of the Adsorbentmentioning

confidence: 99%

Unravelling the Affinity of Alkali-Activated Fly Ash Cubic Foams towards Heavy Metals Sorption

et al. 2022

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In this work, alkali-activated fly ash-derived foams were produced at room temperature by direct foaming using aluminum powder. The 1 cm3 foams (cubes) were then evaluated as adsorbents to extract heavy metals from aqueous solutions. The foams’ selectivity towards lead, cadmium, zinc, and copper ions was evaluated in single, binary, and multicomponent ionic solutions. In the single ion assays, the foams showed much higher affinity towards lead, compared to the other heavy metals; at 10 ppm, the removal efficiency reached 91.9% for lead, 83.2% for cadmium, 74.6% for copper, and 64.6% for zinc. The greater selectivity for lead was also seen in the binary tests. The results showed that the presence of zinc is detrimental to cadmium and copper sorption, while for lead it mainly affects the sorption rate, but not the ultimate removal efficiency. In the multicomponent assays, the removal efficiency for all the heavy metals was lower than the values seen in the single ion tests. However, the superior affinity for lead was preserved. This study decreases the existing knowledge gap regarding the potential of alkali-activated materials to act as heavy metals adsorbents under different scenarios.

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Section: Synthesis Of the Adsorbentmentioning

confidence: 99%

Unravelling the Affinity of Alkali-Activated Fly Ash Cubic Foams towards Heavy Metals Sorption

et al. 2022

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“…The mixture design was selected following previous work (Novais et al, 2019a). The foams synthesis protocol is described in the Supplementary Material.…”

Section: Mixture Design and Foams Preparationmentioning

confidence: 99%

Highly efficient lead extraction from aqueous solutions using inorganic polymer foams derived from biomass fly ash and metakaolin

Novais

Carvalheiras

Seabra

et al. 2020

Journal of Environmental Management

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This work reports a simple and safe, but powerful, route to depollute lead-containing aqueous solutions. Inorganic polymer foams (cm-size) were used as bulk-type adsorbents. The influence of the specimens' porosity and activator molarity on the foams' physical properties and on their lead extraction ability was studied. Then, the best performing samples were deeply evaluated as lead adsorbents by studying the impact of pH, lead concentration, contact time, ionic strength and solution volume. Lead sorption kinetics is strongly affected by the pollutant concentration, pH and the solution ionic strength. Under the most favourable conditions the foams showed an impressive removal capacity (105.9 mg/g at pH 5, 23 � C, C 0 ¼ 800 ppm, deionised water), surpassing all other reported values on the use of bulk-type inorganic polymers. The foams' lead uptake is 2.3 times higher than the previous best performing bulk-type specimens (mm-size spheres), and sorption is 12.5-15 times faster. The foams can be easily regenerated using mild acidic conditions, and then reused as adsorbent, suggesting that the main adsorption mechanism is ion exchange.

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“…Most of the studies published so far in this field focus on the use of inorganic-based wastes as immobilisation agents (Chen et al, 2019b; Moukannaa et al, 2019; Novais et al, 2019). However, inorganic binders seem to be inefficient to avoid the release of DOC and total dissolved solids (TDS) in water (Du et al, 2018; Korotenko et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Non-conventional stabilisation/solidification treatment of industrial wastes with residual powdered paints

Vaccari

Castro

2019

Waste Manag Res

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Stabilisation/solidification technologies are widely used for rendering industrial wastes inert. In this study, residual powdered paints were applied to treat different types of industrial wastes by stabilisation/solidification: Fumes from steel-making process, sludge from coagulation/flocculation treatments and powders from brushing and polishing metallic objects. Stabilisation/solidification trials were performed both under static conditions and in motion. It was observed that the residual paints could polymerise well in 60 min at 120 °C. The addition of water during the treatment resulted in highly porous and friable materials and, therefore, is not recommended. The mixture between wastes and paint influenced polymerisation. Specific heating conditions needed to be tested for each waste, varying from 80 °C to 150 °C. Significant reduction on leachability after treatment could be reached in most cases. Reduction on chlorides release up to 92.0% were achieved. Contents of other elements on the leachates, such as copper, molybdenum, nickel, zinc and dissolved organic carbon, could also be reduced in percentages up to 96.9%, 97.6%, 98.8%, 95.7% and 96.9%, respectively. For some types of wastes, however, especially those containing high contents of copper and mineral oils, the treatment was ineffective. Polymerisation in motion apparently improved binding capacity, but tests with increased content of paints are recommended to reduce the release of dissolved organic carbon.

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In-depth investigation of the long-term strength and leaching behaviour of inorganic polymer mortars containing green liquor dregs

Cited by 15 publications

References 44 publications

Unravelling the Affinity of Alkali-Activated Fly Ash Cubic Foams towards Heavy Metals Sorption

Unravelling the Affinity of Alkali-Activated Fly Ash Cubic Foams towards Heavy Metals Sorption

Highly efficient lead extraction from aqueous solutions using inorganic polymer foams derived from biomass fly ash and metakaolin

Non-conventional stabilisation/solidification treatment of industrial wastes with residual powdered paints

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