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

Abstract

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.

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

“…Their framework is composed by AlO 4 and SiO 4 units linked alternatively by shared oxygen atoms [37]. The oxygen tetrahedra containing the Al 3+ ions has a negative charge, which is balanced by cations such as Na + [38], and this explains the negative zeta potential. The results shown in Figure 2 are in line with previous studies on the topic [39,40].…”

A Bibliometric Analysis of Research Trends in Geopolymer

“…The quantity and analysis of publications on a time-period basis give a good estimate of the trends and status quo in a specific research field and can inform researchers of the probable future research trends in the area. The findings show an increase in geopolymer research, which can be attributed to the discoveries of more precursor materials such as laterite [ 35 ] and growing interest in applications such as fire and heat-resistant structures [ 30 ], water and wastewater treatment [ 57 ], immobilization of heavy metals [ 45 ], cements and concretes [ 58 ], and brick manufacturing [ 26 ]. Furthermore, researchers striving to optimize mix designs and strength, develop low-cost user-friendly activators, utilize low-temperature curing conditions, and advance durability properties have influenced the growth of geopolymer research.…”

A Scientometric Review on Mapping Research Knowledge for 3D Printing Concrete

“…Following the employment of said desirables, a total of 953 records are kept. Similarly, multiple studies have been conducted by using same method [ 41 , 42 , 43 , 44 , 45 ].…”