Geopolymer for use in heavy metals adsorption, and advanced oxidative processes: A critical review

Rasaki, Sefiu Abolaji; Zhang, Bingxue; Guarecuco, Rohiverth; Thomas, Tiju; Yang, Minghui

doi:10.1016/j.jclepro.2018.12.145

Cited by 218 publications

(87 citation statements)

References 102 publications

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“…The adsorption properties of slags reported in Table 5 are significantly lower than those reported for commercial adsorbents (Table 1). Nevertheless, ironmaking and steelmaking slags are still comparatively attractive for use as low-cost adsorbents since they are inexpensive byproducts produced in large volumes [3,4,25,117]. In addition, ironmaking and steelmaking slags have high mechanical strength properties and, as such, the adsorbents derived from these materials are most likely to have desirable properties such as high resistance to abrasion and attrition when in use [117].…”

Section: Opportunities To Enhance the Adsorption Performance Of Slagsmentioning

confidence: 99%

“…Nevertheless, ironmaking and steelmaking slags are still comparatively attractive for use as low-cost adsorbents since they are inexpensive byproducts produced in large volumes [3,4,25,117]. In addition, ironmaking and steelmaking slags have high mechanical strength properties and, as such, the adsorbents derived from these materials are most likely to have desirable properties such as high resistance to abrasion and attrition when in use [117]. Thus, in order to overcome the obvious performance challenges and increase the utilisation potential of slags as adsorbents, several techniques have been proposed to modify the core functional properties of slags in order to improve their adsorption capacities.…”

Section: Opportunities To Enhance the Adsorption Performance Of Slagsmentioning

confidence: 99%

“…Alkali-activated slags, also known as geopolymers, are synthesised from the reaction of a solid aluminosilicate precursor under alkaline conditions to produce a product consisting of hydrous alkali-aluminosilicate and/or alkali-alkali-earth-aluminosilicate phases [74,[117][118][119][120][121][122][123]145]. Geopolymers are amorphous or partly crystalline materials composed of [SiO 4 ] 4− and [AlO 4 ] 5− 3D-tetrahedral structures linked randomly by covalently shared oxygen atoms [74,118,121,123,145].…”

Section: Alkali Activation and Geopolymerisation Of Slagsmentioning

confidence: 99%

See 2 more Smart Citations

Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities

et al. 2020

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This paper critically discusses the structure, properties and applications of ironmaking and steelmaking slags and their silicate-based variants as low-cost adsorbents for removing cations and anions from industrial effluents and wastewater. Undoubtedly, the performance of slag-based adsorbents depends on their physical, chemical and phase chemical properties. The presence of crystalline phases, for example, has a significant effect on the adsorption capacity. However, despite their low cost and ubiquity, their chemical and geometric heterogeneity significantly affects the performance and applications of slag-based adsorbents. These challenges notwithstanding, the efficacy of slag-based adsorbents can be significantly enhanced through purposeful activation to increase the specific surface area and density of adsorption sites on the surfaces of adsorbent particles. The synthesis of functionalised adsorbents such as geopolymers, zeolites and layered double hydroxides from silicate and aluminosilicate precursors can also significantly increase the performance of slag-based adsorbents. In addition, the ability to stabilise the dissolved and/or entrained toxic metal species in stable phases in slags, either through controlled post-process fluxing or crystallisation, can significantly enhance the environmental performance of slag-based adsorbents. Most critical in the design of future slag-based adsorbents is the integration of the engineered properties of molten and solidified slags to the recovery and stabilisation of dissolved and/or entrained metals.

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Section: Opportunities To Enhance the Adsorption Performance Of Slagsmentioning

confidence: 99%

Section: Opportunities To Enhance the Adsorption Performance Of Slagsmentioning

confidence: 99%

Section: Alkali Activation and Geopolymerisation Of Slagsmentioning

confidence: 99%

See 1 more Smart Citation

Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities

et al. 2020

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“…Many studies found that the adsorption phenomenon of heavy metals onto the surface C-S-H. The alkali activated materials were also prepared into adsorbent for removal heavy metals from aqueous solution [43][44][45][46][47][48][49][50][51][52][53]. Then the adsorption of heavy metal onto the surface of the alkali activated gels could be regards as one of the mechanisms of the immobilization.…”

Section: Leaching Propertiesmentioning

confidence: 99%

Low-Carbon Binder for Cemented Paste Backfill: Flowability, Strength and Leaching Characteristics

et al. 2019

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Blast furnace slag was used as the main raw material to prepare the alkali activated slag (AAS), a low-carbon binder, for cemented paste backfill (CPB). The optimum parameters for preparing the AAS binders using an orthogonal experiment were obtained. Under the optimum conditions (NaOH content was 3 wt. %, Ordinary Portland cement (OPC) content was 7 wt. %, and gypsum dosage was 4 wt. %), the 28 days compressive strength of the binder was 29.55 MPa. The flow ability of the fresh CPB slurry decreased with solid content due to the increased yield stress, while the flow ability increased when rising the binder dosage. A predictive model for the compressive strength of CPB samples was reached through multivariate analysis and the R2 values were higher than 0.9. Sensitivity analysis showed that the solid content is the most important parameter which influences on the development of the CPB strength with a correlation coefficient of 0.826. From the Toxicity Characteristic Leaching Procedure (TCLP) tests, the leaching concentrations of Pb and Cd were below the threshold. As a result, the AAS has potential application as an alternative binder and cemented paste backfill.

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“…Although many of the above-mentioned studies were dealing with tailings resulting from tungsten and gold mines, several studies have also been produced targeting copper mine tailings [16,[19][20][21][22][23]. From an environmental perspective, it is important to highlight that alkaline activation has already proved to be very effective for containing and neutralising different types of wastes [24][25][26][27][28][29][30][31][32][33][34][35] and, specifically, wastes resulting from mine operations [36][37][38][39], a capacity that reinforces the potential for this technique to stabilise mine tailings.Nevertheless, a decisive breakthrough has yet to be achieved, one might say. Alkali activation for mine tailings stabilisation, for an industrial application or landfilling, is not yet a common option because of the logistical difficulties associated with the implementation of such an operation.…”

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confidence: 99%

Recycling and Application of Mine Tailings in Alkali-Activated Cements and Mortars—Strength Development and Environmental Assessment

et al. 2020

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Mine tailings (MT) could represent a step forward in terms of the quality of the aggregates usually used in civil engineering applications, mostly due to its high density. The Portuguese Neves Corvo copper mine, owned by the Lundin Mining Corporation, produces approximately 3 million tonnes per year. Nevertheless, it cannot be used in its original state, due to its high levels of sulphur and other metals (As, Cr, Cu, Pb, Zn). This paper focuses on the stabilisation/solidification of high-sulphur MT, without any previous thermal treatment, using alkali-activated fly ash (FA). The variables considered were the MT/FA ratio and the activator type and concentration. A fine aggregate was then added to the pastes to assess the quality of the resulting mortar. Maximum compressive strengths of 14 MPa and 24 MPa were obtained for the pastes and mortars, respectively, after curing for 24 h at 85 • C. Thermogravimetric analysis, scanning electron microscopy, X-ray energy dispersive spectroscopy, X-ray diffraction, and infrared spectroscopy were used to characterize the reaction products, and two types of leaching tests were performed to assess the environmental performance. The results showed that the strength increase is related with the formation of a N-A-S-H gel, although sodium sulphate carbonate was also developed, suggesting that the total sodium intake could be optimized without strength loss. The solubility of the analysed metals in the paste with 78% MT and 22% FA was below the threshold for non-hazardous waste. potential use of MT as a replacement for natural aggregates, which are usually obtained through an extraction process that severely affects the environment, would not only reduce the consumption of natural resources but also decrease the volume of landfilled MT. However, this waste generates acid mine drainage when exposed to oxygen and water [5], which makes it impractical as an aggregate in common applications, like embankments or roads, if not previously stabilised.Another possible use is inclusion in alkali-activated mortar and concrete, a recent research topic, with promising results in terms of mechanical and environmental performance [5,6]. Some studies focused on the use of MT as a precursor, albeit requiring a previous thermal treatment [7][8][9][10][11], while others used a different approach by considering the MT as a filler and/or coarse aggregate in composite materials, cemented by aluminosilicate gel formed from the alkali activation of fly ash, metakaolin, waste glass, or slags [11][12][13][14][15][16][17][18][19]. Although many of the above-mentioned studies were dealing with tailings resulting from tungsten and gold mines, several studies have also been produced targeting copper mine tailings [16,[19][20][21][22][23]. From an environmental perspective, it is important to highlight that alkaline activation has already proved to be very effective for containing and neutralising different types of wastes [24][25][26][27][28][29][30][31][32][33][34][35] and, specifically, wastes resulting from m...

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Geopolymer for use in heavy metals adsorption, and advanced oxidative processes: A critical review

Cited by 218 publications

References 102 publications

Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities

Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities

Low-Carbon Binder for Cemented Paste Backfill: Flowability, Strength and Leaching Characteristics

Recycling and Application of Mine Tailings in Alkali-Activated Cements and Mortars—Strength Development and Environmental Assessment

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