Mechanisms of Heavy Metal Immobilisation using Geopolymerisation Techniques – A review

Vu, Tran Huyen; Gowripalan, Nadarajah

doi:10.3151/jact.16.124

Cited by 64 publications

(14 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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

View full text Add to dashboard Cite

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.

show abstract

Section: Curing Temperature and Timementioning

confidence: 99%

Factors Affecting the Compressive Strength of Geopolymers: A Review

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The greatest advantages of geopolymers are strong bonding and good durability, high-temperature resistance, low permeability, great chemical corrosion resistance, and environmental friendliness [ 1 ]. Potential fields of application of geopolymer materials include geopolymer concrete, precast construction elements, materials on pavement, repair materials, protective coatings, immobilization of toxic metals, nuclear waste management, and three-dimensional printing materials [ 7 , 8 , 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Changes in the Microstructure of Geopolymer Mortar after Exposure to High Temperatures

Dudek

Sitarz

2020

Materials

View full text Add to dashboard Cite

The inorganic structure formed at the stage of setting of the geopolymer binder ensures high durability of the material under high-temperature conditions. However, changes in the microstructure of the material are observed. The purpose of the study was to analyze changes in the structure of geopolymer mortar after exposure to high temperatures T = 200, 400, 600, 800, and 1000 °C. Mortars with a binder based solely on fly ash (FA) and mixed in the 1:1 ratio with a binder containing fly ash and ground granulated blast-furnace slag (GGBFS) were tested. The descriptions of their microstructures were prepared based on digital microscope observations, scanning electron microscope (SEM) observations, EDS (energy dispersive spectroscopy) analysis, and mercury intrusion porosimetry (MIP) porosity test results. Changes in the material due to high temperature were observed. The differences in the microstructure of the samples are also visible in the materials that were not exposed to temperature, which was influenced by the composition of the materials. Porosity increases with increasing annealing temperature. The distribution of individual pores also changes. In both materials, the proportion of pores larger than 1000 nm increases with the temperature increase. Moreover, the number of cracks and their width also increases, reaching 20 µm in the case of GGBFS. Furthermore, the color of geopolymers has changed. The obtained results extend the current state of knowledge in the field of changes in the microstructure of geopolymers subjected to high temperature.

show abstract

“…The remediation of contaminated water is of prime significance because of the escalating freshwater consumption of water, resulting in a grave shortage in most large parts of the world. To address this challenge, water and wastewater treatments, by means of geopolymers, have proven to be unique owing to their three-dimensional (3D) network structure, which marvelously makes geopolymers the most promising adsorbents [ 175 , 176 ]. Previous studies have revealed the immobilization of different heavy metals in geopolymers, for instance, Pb +2 , and shown that geopolymers are competent enough to absorb the heavy metals Pb +2 , Cu +2 , Cr +3 , Cd +2 , etc.…”

Section: Applications Of Geopolymers For Water and Wastewater Treatmentmentioning

confidence: 99%

A State-of-the-Art Review on Innovative Geopolymer Composites Designed for Water and Wastewater Treatment

Luhar

Abdullah

et al. 2021

Materials

View full text Add to dashboard Cite

There is nothing more fundamental than clean potable water for living beings next to air. On the other hand, wastewater management is cropping up as a challenging task day-by-day due to lots of new additions of novel pollutants as well as the development of infrastructures and regulations that could not maintain its pace with the burgeoning escalation of populace and urbanizations. Therefore, momentous approaches must be sought-after to reclaim fresh water from wastewaters in order to address this great societal challenge. One of the routes is to clean wastewater through treatment processes using diverse adsorbents. However, most of them are unsustainable and quite costly e.g. activated carbon adsorbents, etc. Quite recently, innovative, sustainable, durable, affordable, user and eco-benevolent Geopolymer composites have been brought into play to serve the purpose as a pretty novel subject matter since they can be manufactured by a simple process of Geopolymerization at low temperature, lower energy with mitigated carbon footprints and marvellously, exhibit outstanding properties of physical and chemical stability, ion-exchange, dielectric characteristics, etc., with a porous structure and of course lucrative too because of the incorporation of wastes with them, which is in harmony with the goal to transit from linear to circular economy, i.e., “one’s waste is the treasure for another”. For these reasons, nowadays, this ground-breaking inorganic class of amorphous alumina-silicate materials are drawing the attention of the world researchers for designing them as adsorbents for water and wastewater treatment where the chemical nature and structure of the materials have a great impact on their adsorption competence. The aim of the current most recent state-of-the-art and scientometric review is to comprehend and assess thoroughly the advancements in geo-synthesis, properties and applications of geopolymer composites designed for the elimination of hazardous contaminants viz., heavy metal ions, dyes, etc. The adsorption mechanisms and effects of various environmental conditions on adsorption efficiency are also taken into account for review of the importance of Geopolymers as most recent adsorbents to get rid of the death-defying and toxic pollutants from wastewater with a view to obtaining reclaimed potable and sparkling water for reuse offering to trim down the massive crisis of scarcity of water promoting sustainable water and wastewater treatment for greener environments. The appraisal is made on the performance estimation of Geopolymers for water and wastewater treatment along with the three-dimensional printed components are characterized for mechanical, physical and chemical attributes, permeability and Ammonium (NH4+) ion removal competence of Geopolymer composites as alternative adsorbents for sequestration of an assortment of contaminants during wastewater treatment.

show abstract

Mechanisms of Heavy Metal Immobilisation using Geopolymerisation Techniques – A review

Cited by 64 publications

References 58 publications

Factors Affecting the Compressive Strength of Geopolymers: A Review

Factors Affecting the Compressive Strength of Geopolymers: A Review

Analysis of Changes in the Microstructure of Geopolymer Mortar after Exposure to High Temperatures

A State-of-the-Art Review on Innovative Geopolymer Composites Designed for Water and Wastewater Treatment

Contact Info

Product

Resources

About