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PublicationDiverse material based geopolymer towards heavy metals removal: a review( 2023)
;Pilomeena Arokiasamy ; ; ;Monower Sadique ; ; ;Mohd Remy Rozainy Mohd Arif ZainolMetakaolin is a commonly used aluminosilicate material for the synthesis of geopolymer based adsorbent. However, it presents characteristics that restrict its uses such as weak rheological properties brought on by the plate-like structure, processing challenges, high water demand and quick hydration reaction. Industrial waste, on the other hand, contains a variety of components and is a potential source of aluminosilicate material. Geopolymer adsorbent synthesized by utilizing industrial waste contains a wide range of elements that offer better ion-exchangeability and increase active sites on the surface of geopolymer. However, limited studies focused on the synthesized of geopolymer based adsorbent by utilizing industrial waste for heavy metal adsorption in wastewater treatment. Therefore, this paper reviews on the raw materials used in the synthesis of geopolymer for wastewater treatment. This would help in the development of low cost geopolymer based adsorbent that has a great potential for heavy metal adsorption, which could deliver double benefit in both waste management and wastewater treatment.19 2 -
PublicationSustainable geopolymer adsorbents utilizing silica fume as a partial replacement for metakaolin in the removal of copper ion from synthesized copper solution(Elsevier Ltd, 2025-07)
;Pilomeena Arokiasamy ; ;Eva Arifi ; ;Md Azree Othuman Mydin ;Andrei Victor Sandu ;Shafiq IshakBiochar has great significance for controlling heavy metal pollution. Nevertheless, its application is impeded by certain shortcomings, such as a limited adsorption capacity, a slow adsorption rate, and poor reusability. Besides, the physical adsorption capacity of raw biochar to heavy metals is suboptimal. As a result, researchers prefer to use geopolymer-based adsorbents for the removal of heavy metals due to their excellent immobilization effect. However, no research has been done on the synthesis of geopolymer-based adsorbent using silica fume for heavy metal adsorption. Thus, the aim of this study is to partially replace metakaolin (MK) with silica fume (S1) (25, 50, 75 and 100 %) in geopolymer formulation at varied S:L ratio (0.4, 0.6, 0.8 and 1.0) to study the impact on the geopolymerization and its following properties in the removal efficiency of copper (Cu2 +). Characterization techniques such as Energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM) and Energy dispersive X-ray spectroscopy (EDX) were used to study the physicochemical properties of the developed geopolymer. The concentration of Cu2+ before and after adsorption was determined by Atomic absorption spectroscopy (AAS) and the removal efficiency was calculated. Based on the experimental result, the geopolymer prepared with 25 % MK and 75 % S1 at S:L of 0.6 maintained the high removal efficiency of Cu2+ (99.62 %) with 100 % MK geopolymer (98.56 %). The generation of N-A-S-H gel with the 75 % replacement level of S1 producing more reactive Si and Al binding sites for Cu2+ adsorption. In addition, S1 contains exchangeable cations such as Ca2+, Mg2+ and Na+ which further promote the adsorption of Cu2+ by ion exchange. Moreover, the mechanisms such as chemical bonding and precipitation were involved in the adsorption of Cu2+. Hence, this research could serve as a basis for the development of solid waste based geopolymers that could remove heavy metal ions from aqueous solution.