Geopolymer synthetized from sludge residue pretreated by the wet alkalinizing method: Compressive strength and immobilization efficiency of heavy metal

Sun, Shichang; Lin, Junhao; Zhang, Peixin; Lin, Fang; Ma, Rui; Quan, Zonggang; Song, Xin

doi:10.1016/j.conbuildmat.2018.03.068

Cited by 41 publications

(37 citation statements)

References 30 publications

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“…Geopolymers, in the family of inorganic aluminosilicate binder, has received extensive interests because of high temperature resistance [70,[102][103][104][105], low permeability [106][107][108][109][110], strong bonding and good durability [51,[111][112][113], excellent chemical corrosion resistance [114][115][116][117][118], and environmental friendliness [119,120], etc. Some of the uses that have been investigated for alkaline activated materials are: as sustainable construction material [121][122][123][124][125][126], mine backfilling [127,128], porous spheres as novel pH buffers [129,130], bricks [71,112,131,132], porous thermal insulation material [133], as road material [134], for immobilization of toxic metals and nuclear waste management [135][136][137][138][139][140], coatings for concrete [141]…”

Section: Curing Temperature and Timementioning

confidence: 99%

Factors Affecting the Compressive Strength of Geopolymers: A Review

et al. 2021

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Geopolymers are created by mixing a source of aluminosilicates, which can be natural or by-products from other industries, with an alkaline solution. These materials based on by-products from other industries have proven to be a less polluting alternative for concrete production than ordinary Portland cement (OPC). Geopolymers offer many advantages over OPC, such as excellent mechanical strength, increased durability, thermal resistance, and excellent stability in acidic and alkaline environments. Within these properties, mechanical strength, more specifically compressive strength, is the most important property for analyzing geopolymers as a construction material. For this reason, this study compiled information on the different variables that affect the compressive strength of geopolymers, such as Si/Al ratio, curing temperature and time, type and concentration of alkaline activator, water content, and the effect of impurities. From the information collected, it can be mentioned that geopolymers with Si/Al ratios between 1.5 and 2.0 obtained the highest compressive strengths for the different cases. On the other hand, high moderate temperatures (between 80 and 90 °C) induced higher compressive strengths in geopolymers, because the temperature favors the geopolymerization process. Moreover, longer curing times helped to obtain higher compressive strengths for all the cases analyzed. Furthermore, it was found that the most common practice is the use of sodium hydroxide combined with sodium silicate to obtain geopolymers with good mechanical strength, where the optimum SS/NaOH ratio depends on the source of aluminosilicates to be used. Generally speaking, it was observed that higher water contents lead to a decrease in compressive strength. The presence of calcium was found to be favorable in controlled proportions as it increases the compressive strength of geopolymers, on the other hand, impurities such as heavy metals have a negative effect on the compressive strength of geopolymers.

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Section: Curing Temperature and Timementioning

confidence: 99%

Factors Affecting the Compressive Strength of Geopolymers: A Review

et al. 2021

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“…Because of its excellent performance and energy saving, it has been widely used in many fields. Such as pavement repair [87], 3D printing [88], anticorrosive coatings [89], curing pol-lutants [90,91], etc. Despite many advantages, geopoly-mers have similar disadvantages to cement-based mate-rials, namely poor toughness and relatively low flexural strength [92].…”

Section: Research Progress Of Graphene Modified Geopolymermentioning

confidence: 99%

Review on the research progress of cement-based and geopolymer materials modified by graphene and graphene oxide

Liu

Huang

et al. 2020

Nanotechnology Reviews

181

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AbstractIn recent years, with the higher requirements for the performance of cement-based materials and the call for energy conservation and environmental protection, a wave of research on new materials has set off, and various high-performance concrete and more environmentally friendly geopolymers have appeared in the public. With a view to solving the defects of energy consumption, environmental protection and low toughness of traditional cement-based materials. At the same time, nanomaterials have become a focus of current research. Therefore, the research on the properties of cement-based materials and geopolymers modified by graphene and its derivatives has aroused extensive interest of researchers. Graphene-based nanomaterials are one of them. Because of their large specific surface area, excellent physical properties have been favored by many researchers. This paper reviews the research progress of graphene-based nanomaterials in improving the properties of cement-based materials and geopolymer materials, and points out the main challenges and development prospects of such materials in the construction field in the future.

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“…It should be noted that the heavy metal concentrations in the geopolymers were at extremely high levels, namely 20,000 and 40,000 mg/kg, but despite this, they were almost completely immobilized by the geopolymers. The typical contents in actual hazardous wastes, respectively, for Pb 2+ and Ni 2+ are: 398 and 90 mg/kg in municipal solid waste incineration fly ash [ 53 ], 1129 and 1420 mg/kg in municipal solid waste incineration bottom ash [ 54 ], 8966 and 50 mg/kg in waste glass from the spent fluorescent lamps [ 55 ], and 7060 and 93 mg/kg in sludge from wastewater treatment [ 56 ].…”

Section: Resultsmentioning

confidence: 99%

Immobilization of Heavy Metals in Boroaluminosilicate Geopolymers

et al. 2021

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Boroaluminosilicate geopolymers were used for the immobilization of heavy metals. Then, their mechanical properties, phase composition, structure, and microstructure were investigated. The addition of borax and boric acid did not induce the formation of any crystalline phases. Boron was incorporated into the geopolymeric network and caused the formation of N–B–A–S–H (hydrated sodium boroaluminosilicate) gel. In the range of a B/Al molar ratio of 0.015–0.075, the compressive strength slightly increased (from 16.1 to 18.7 MPa), while at a ratio of 0.150, the compressive strength decreased (to 12 MPa). Heavy metals (lead and nickel) were added as nitrate salts. The loss of the strength of the geopolymers induced by heavy metals was limited by the presence of boron. However, it caused an increase in heavy metal leaching. Despite this, heavy metals were almost entirely immobilized (with immobilization rates of >99.8% in the case of lead and >99.99% in the case of nickel). The lower immobilization rate of lead was due to the formation of macroscopic crystalline inclusions of PbO·xH2O, which was vulnerable to leaching.

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Geopolymer synthetized from sludge residue pretreated by the wet alkalinizing method: Compressive strength and immobilization efficiency of heavy metal

Cited by 41 publications

References 30 publications

Factors Affecting the Compressive Strength of Geopolymers: A Review

Factors Affecting the Compressive Strength of Geopolymers: A Review

Review on the research progress of cement-based and geopolymer materials modified by graphene and graphene oxide

Immobilization of Heavy Metals in Boroaluminosilicate Geopolymers

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