Encapsulation of toxic heavy metals from waste CRT using calcined kaolin base-geopolymer

Guzmán-Carrillo, H.R.; Gasca-Tirado, José Ramón; López-Romero, J. Mauricio; Luis, Morales-Aranibar; Eric, M.; Pineda-Piñón, Jorge; Pérez-Bueno, J.J.; Feregrino-Montes, C.; López-Naranjo, Edgar J.; Manzano-Ramı́rez, A.

doi:10.1016/j.matchemphys.2020.123745

Cited by 20 publications

(6 citation statements)

References 23 publications

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“…A comparatively big difference between the content of Pb in an extract from unstabilized soils (CRT powdered glass and raw material) and a geopolymer containing CRT glass is reported by Ogundiran et al [ 36 ]. Introducing CRT glass into the geopolymer mixture has not been very popular so far, but a lot of scientists successfully encapsulated separate heavy metals within the geopolymer matrix [ 37 , 59 , 60 , 61 , 62 , 63 ]. Many scientific investigations prove also similar capabilities of concrete for the encapsulation of lead from CRT glass and substantial reductions in Pb leaching [ 16 , 18 , 19 , 34 ].…”

Section: Discussionmentioning

confidence: 99%

“…For maximal CRT glass content equal to 20%, the requirements concerning leachable Pb were fulfilled [ 36 ]. According to the most recent studies reported by Carrillo et al [ 37 ], even up to 20% (with respect to the weight of metakaolin) of CRT glass of sizes 0.01 mm to 1.10 mm can be incorporated into the geopolymer matrix in a way that is (according to the leaching test) safe for the environment. Scientists indicate that low alkaline conditions promote immobilization of toxic metals.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of Metakaolin-Based Geopolymer with Cathode Ray Tube Glass

et al. 2021

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Geopolymers can be treated as an environmentally friendly alternative for concrete and enables utilization of various wastes. This paper focuses on the possibility of application of discarded cathode ray tube (CRT) glass inside a metakaolin-based geopolymer in the form of an aggregate, providing an ecological method of recycling of this hazardous material. The main goal of this paper was to develop an optimal composition of a new geopolymer and to describe its behavior under varying curing conditions. A geopolymer made of different mixtures was subjected to flexural and compressive strength tests. The density, mass loss, temperature changes, and metals leaching were determined as well. The results demonstrated that neither the content of CRT glass nor the curing regime has a significant influence on the mechanical behavior. However, the strength of the geopolymer containing 50% CRT glass by mass increased with time in contrast to a geopolymer with a higher CRT glass content. The development of temperature inside the mixture was dependent on the amount of metakaolin. The concentration of toxic metals in an aqueous extract decreased considerably after the encapsulation of CRT glass inside the geopolymer. The presented results indicate that discarded CRT glass can be considered an aggregate for a metakaolin-based geopolymer. The new material shows high strength and makes the CRT glass safe for the environment.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characteristics of Metakaolin-Based Geopolymer with Cathode Ray Tube Glass

et al. 2021

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“…In geopolymers, certain cations such as Na + and Ca 2+ are present in the voids of the three-dimensional mesh structure to neutralize the charge imbalance due to the partial replacement of Si 4+ by Al 3+ . At the same time, Mn 2+ will also be wrapped by the reticular structure of the geopolymer to achieve the effect of immobilization [ 44 ]. In addition, the free Mn 2+ will also generate stable Mn(OH) 2 under alkaline conditions during the reaction process, and the relevant reaction equation is shown below.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Electrolytic Manganese Slag–Solid Waste-Based Geopolymers: Compressive Strength and Mn Immobilization

Mi,

Zhao,

et al. 2024

Materials

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The massive stockpiling of electrolytic manganese residue (EMR) has caused serious environmental pollution. In this study, EMR, coal gangue (CG), and fly ash (FA) were used as raw materials to obtain the optimal mix ratio based on Design-Expert mixture design. The effects of activator modulus, liquid–solid (L/S) ratio, and curing temperature on the mechanical properties of geopolymers were investigated. The results showed that the compressive strength of the prepared geopolymer was 12.0 MPa, and the 28d leaching of Mn was 0.123 mg/L under the conditions of EMR:CG:FA = 0.43:0.34:0.23, L/S = 0.9, a curing temperature of 60 °C, and a curing time of 24 h. This indicates that the geopolymer is an environmentally friendly material with high compressive strength. The mineral composition of the geopolymer is mainly hydrated calcium silicate and geopolymer gel. In addition, a more stable new mineral phase, MnSiO3, was generated. The Fourier transform infrared (FTIR) spectrogram showed that the peak at 1100 m−1 was shifted to 1112 cm−1, which indicated that a geopolymerization reaction had occurred. Through scanning electron microscopy (SEM) and energy dispersive spectrum (EDS) analysis, it was identified that the geopolymerization produced a large amount of amorphous gelatinous substances with a relatively dense structure, the major elements being oxygen, silicon, aluminum, calcium, and sodium.

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“…While the strength and leachability results of S/S products are competitive with those using traditional binders [ 182 , 183 ], the costly activators that enable the synthesis of the geopolymers (sodium or potassium hydroxides, liquid water glass) block their widespread use. The situation is partly alleviated by the fact that geopolymers based on slag [ 184 ] and fly ash [ 58 , 185 ] are currently being produced and studied in addition to metakaolin-based geopolymers [ 99 , 186 ]. These raw materials, as waste materials, increase the ecological value of the solution, which, in addition to very good characteristics, opens the possibility of its dissemination.…”

Section: Characteristic Of Binders Amendments and Additivesmentioning

confidence: 99%

Does Current Knowledge Give a Variety of Possibilities for the Stabilization/Solidification of Soil Contaminated with Heavy Metals?—A Review

Lal

Fronczyk

2022

Materials

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Stabilization/solidification of contaminated soil is a process that allows simultaneous strengthening of the soil structure, disposal of contamination and recycling of industrial waste, implemented as substitutes for Portland cement or additives to improve the properties of the final product obtained. Extremely intensive development of studies pertaining to the S/S process prompted the authors to systematize the binders used and the corresponding methods of binding the contamination, and to perform an analysis of the effectiveness expressed in geomechanical properties and leachability. The study pays close attention to the types of additives and binders of waste origin, as well as the ecological and economic benefits of their use. The methods of preparing and caring for the specimens were reviewed, in addition to the methods of testing the effectiveness of the S/S process, including the influence of aging factors on long-term properties. The results of the analyses carried out are presented in the form of diagrams and charts, facilitating individual evaluation of the various solutions for the stabilization/solidification of soils contaminated with heavy metals.

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Encapsulation of toxic heavy metals from waste CRT using calcined kaolin base-geopolymer

Cited by 20 publications

References 23 publications

Characteristics of Metakaolin-Based Geopolymer with Cathode Ray Tube Glass

Characteristics of Metakaolin-Based Geopolymer with Cathode Ray Tube Glass

Synthesis of Electrolytic Manganese Slag–Solid Waste-Based Geopolymers: Compressive Strength and Mn Immobilization

Does Current Knowledge Give a Variety of Possibilities for the Stabilization/Solidification of Soil Contaminated with Heavy Metals?—A Review

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