Now showing 1 - 8 of 8
  • Publication
    Metakaolin/sludge based geopolymer adsorbent on high removal efficiency of Cu2+
    ( 2022)
    Pilomeena Arokiasamy
    ;
    ; ;
    Mohd Remy Rozainy Mohd Arif Zainol
    ;
    ;
    Marwan Kheimi
    ;
    Andrei Victor Sandu
    ;
    Petrica Vizureanu
    ;
    Rafiza Abdul Razak
    ;
    Activated carbon (AC) has received a lot of interest from researchers for the removal of heavy metals from wastewater due to its abundant porous structure. However, it was found unable to meet the required adsorption capacity due to its amorphous structure which restricts the fundamental studies and structural optimization for improved removal performance. In addition, AC is not applicable in large scale wastewater treatment due its expensive synthesis and difficulty in regeneration. Thus, the researchers are paying more attention in synthesis of low cost geopolymer based adsorbent for heavy metal removal due its excellent immobilization effect. However, limited studies have focused on the synthesis of geopolymer based adsorbent for heavy metal adsorption by utilizing industrial sludge. Thus, the aim of this research was to develop metakaolin (MK) based geopolymer adsorbent with incorporation of two types of industrial sludge (S1 and S3) that could be employed as an adsorbent for removing copper (Cu²⁺) from aqueous solution through the adsorption process. The effects of varied solid to liquid ratio (S/L) on the synthesis of metakaolin/sludge based geopolymer adsorbent and the removal efficiency of Cu²⁺ by the synthesis adsorbent were studied. The raw materials and synthesized geopolymer were characterized by using x-ray fluorescence (XRF), x-ray diffraction (XRD), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and micro XRF. The concentration of Cu²⁺ before and after adsorption was determined by atomic absorption spectroscopy (AAS) and the removal efficiency was calculated. The experimental data indicated that the synthesized geopolymer at low S/L ratio has achieved the highest removal efficiency of Cu²⁺ about 99.62% and 99.37% at 25%:75% of MK/S1 and 25%:75% of MK/S3 respectively compared to pure MK based geopolymer with 98.56%. The best S/L ratio for MK/S1 and MK/S3 is 0.6 at which the reaction between the alkaline activator and the aluminosilicate materials has improved and enhanced the geopolymerization process. Finally, this work clearly indicated that industrial sludge can be utilized in developing low-cost adsorbent with high removal efficiency
  • Publication
    Assessment of the suitability of ceramic waste in geopolymer composites: an appraisal
    ( 2021)
    Ismail Luhar
    ;
    Salmabanu Luhar
    ;
    ;
    Marcin Nabiałek
    ;
    Andrei Victor Sandu
    ;
    Janusz Szmidla
    ;
    Anna Jurczyńska
    ;
    Rafiza Abdul Razak
    ;
    Ikmal Hakem A Aziz
    ;
    ;
    Laila Mardiah Deraman
    Currently, novel inorganic alumino-silicate materials, known as geopolymer composites, have emerged swiftly as an ecobenevolent alternative to contemporary ordinary Portland cement (OPC) building materials since they display superior physical and chemical attributes with a diverse range of possible potential applications. The said innovative geopolymer technology necessitates less energy and low carbon footprints as compared to OPC-based materials because of the incorporation of wastes and/or industrial byproducts as binders replacing OPC. The key constituents of ceramic are silica and alumina and, hence, have the potential to be employed as an aggregate to manufacture ceramic geopolymer concrete. The present manuscript presents a review of the performance of geopolymer composites incorporated with ceramic waste, concerning workability, strength, durability, and elevated resistance evaluation.
  • Publication
    Phase transformation of Kaolin-Ground Granulated Blast Furnace Slag from geopolymerization to sintering process
    ( 2021) ; ; ;
    Mohamad Hasmaliza
    ;
    ;
    Ikmal Hakem A. Aziz
    ;
    Bartłomiej Jeż
    ;
    Marcin Nabiałek
    The main objective of this research was to investigate the influence of curing temperature on the phase transformation, mechanical properties, and microstructure of the as-cured and sintered kaolin-ground granulated blast furnace slag (GGBS) geopolymer. The curing temperature was varied, giving four different conditions; namely: Room temperature, 40, 60, and 80 °C. The kaolin-GGBS geopolymer was prepared, with a mixture of NaOH (8 M) and sodium silicate. The samples were cured for 14 days and sintered afterwards using the same sintering profile for all of the samples. The sintered kaolin-GGBS geopolymer that underwent the curing process at the temperature of 60 °C featured the highest strength value: 8.90 MPa, and a densified microstructure, compared with the other samples. The contribution of the Na2O in the geopolymerization process was as a self-fluxing agent for the production of the geopolymer ceramic at low temperatures.
  • Publication
    Self-Fluxing mechanism in geopolymerization for Low-Sintering temperature of ceramic
    ( 2021) ; ; ;
    Hasmaliza Mohamad
    ;
    ;
    Penphitcha Amonpattaratkit
    ;
    Joanna Gondro
    ;
    Wojciech Sochacki
    ;
    Norfadhilah Ibrahim
    Kaolin, theoretically known as having low reactivity during geopolymerization, was used as a source of aluminosilicate materials in this study. Due to this concern, it is challenging to directly produce kaolin geopolymers without pre-treatment. The addition of ground granulated blast furnace slag (GGBS) accelerated the geopolymerization process. Kaolin–GGBS geopolymer ceramic was prepared at a low sintering temperature due to the reaction of the chemical composition during the initial stage of geopolymerization. The objective of this work was to study the influence of the chemical composition towards sintering temperature of sintered kaolin–GGBS geopolymer. Kaolin–GGBS geopolymer was prepared with a ratio of solid to liquid 2:1 and cured at 60 °C for 14 days. The cured geopolymer was sintered at different temperatures: 800, 900, 1000, and 1100 °C. Sintering at 900 °C resulted in the highest compressive strength due to the formation of densified microstructure, while higher sintering temperature led to the formation of interconnected pores. The difference in the X-ray absorption near edge structure (XANES) spectra was related to the phases obtained from the X-ray diffraction analysis, such as akermanite and anothite. Thermal analysis indicated the stability of sintered kaolin–GGBS geopolymer when exposed to 1100 °C, proving that kaolin can be directly used without heat treatment in geopolymers. The geopolymerization process facilitates the stability of cured samples when directly sintered, as well as plays a significant role as a self-fluxing agent to reduce the sintering temperature when producing sintered kaolin–GGBS geopolymers.
  • Publication
    Alkaline-Activation technique to produce low-temperature sintering activated-HAp ceramic
    ( 2023) ; ; ;
    Hasmaliza Mohamad
    ;
    ;
    Andrei Victor Sandu
    ;
    Petrica Vizureanu
    ;
    Madalina Simona Baltatu
    ;
    Patimapon Sukmak
    The fabrication of hydroxyapatite (HAp) ceramics prepared by existing conventional sintering requires high-temperature sintering of 1250 °C to 1300 °C. In this paper, the activated metakaolin (MK)/HAp specimens were prepared from varied mix design inputs, which were varied solid mixtures (different amounts of MK loading in HAp) and liquid-to-solid (L/S) ratios, before being pressed and sintered at 900 °C. Phase analysis, thermal analysis, surface morphology, and tensile strength of the specimens were investigated to study the influences of the Al, Si, Fe, Na, and K composition on the formation of the hydroxyapatite phase and its tensile strength. XRD analysis results show the formation of different phases was obtained from the different mix design inputs HAp (hexagonal and monoclinic), calcium phosphate, sodium calcium phosphate silicate and calcium hydrogen phosphate hydrate. Interestingly, the specimen with the addition of 30 g MK prepared at a 1.25 L/S ratio showed the formation of a monoclinic hydroxyapatite phase, resulting in the highest diametrical tensile strength of 12.52 MPa. Moreover, the increment in the MK amount in the specimens promotes better densification when sintered at 900 °C, which was highlighted in the microstructure study. This may be attributed to the Fe2O3, Na2O, and K2O contents in the MK and alkaline activator, which acted as a self-fluxing agent and contributed to the lower sintering temperature. Therefore, the research revealed that the addition of MK in the activated-HAp system could achieve a stable hydroxyapatite phase and better tensile strength at a low sintering temperature.
      3  10
  • Publication
    Hydroxyapatite/Dolomite alkaline activated material reaction in the formation of low temperature sintered ceramic as adsorbent materials
    ( 2022-09-26)
    Kamarzamann F.F.
    ;
    ; ;
    Abdul Kadir A.
    ;
    ;
    Wan Ibrahim W.M.
    ;
    Victor Sandu A.
    Hazardous pollutants, especially heavy metals in wastewater, have become a major concern due to the high potential of causing serious problems to humans and aquatic ecosystems, such as adverse health effects, environmental damage, and air pollution. The adsorption process is widely used to remove heavy metals because it is inexpensive, simple, and environmentally friendly. However, recent studies have shown that some adsorbents such as activated carbon, ion exchange resins, and carbon nanotubes are becoming more expensive due to their complex production. Considering these problems, alkali-activated materials (AAMs) can be considered as a new potential adsorbent material due to their excellent physical, chemical, and mechanical properties, which make them suitable for use in the field of civil engineering. Dolomite is one of the AAMs that is capable of adsorbing hazardous pollutants such as heavy metals in wastewater due to its unique structure. This material is also classified as a cost-effective adsorbent because it is abundant and can be found all over the world. Nevertheless, few studies have focused on the adsorption method using dolomite as a precursor material to remove heavy metals in wastewater, and currently only limited studies focus on the relationship between dolomite and hydroxyapatite (HAP). In addition, some studies have shown that the properties of geopolymers can be improved (up to 40%) when a moderate amount of calcium-containing material is added to the geopolymer. Although they have been used as a stand-alone material with excellent properties, combining them with another material could be another way to improve their properties. Therefore, this review provides an in-depth analysis on the properties of dolomite as a new potential precursor material in combination with HAP for contaminant removal. This would help to find the best parameters for the geopolymerization process between dolomite and HAP to meet the adsorption method requirements. This paper also investigated the ability of HAP as a carrier with the combination of bacterial strains via an immobilization process to improve the properties of dolomite as a geopolymer adsorbent. A microbial community can also act as an adsorbent for the removal of heavy metals and inorganic/organic contaminants from wastewater. This review can serve as a basis for understanding the ability of dolomite/HAP as a new alkali-activated material in geopolymer adsorbents in combination with immobilizing bacteria to remove heavy metals in wastewaters.
      1  4
  • Publication
    Metakaolin/sludge based geopolymer adsorbent on high removal efficiency of Cu2+
    ( 2022)
    Pilomeena Arokiasamy
    ;
    ; ;
    Mohd Remy Rozainy Mohd Arif Zainol
    ;
    ;
    Marwan Kheimi
    ;
    Jitrin Chaiprapa
    ;
    Andrei Victor Sandu
    ;
    Petrica Vizureanu
    ;
    ;
    Activated carbon (AC) has received a lot of interest from researchers for the removal of heavy metals from wastewater due to its abundant porous structure. However, it was found unable to meet the required adsorption capacity due to its amorphous structure which restricts the fundamental studies and structural optimization for improved removal performance. In addition, AC is not applicable in large scale wastewater treatment due its expensive synthesis and difficulty in regeneration. Thus, the researchers are paying more attention in synthesis of low cost geopolymer based adsorbent for heavy metal removal due its excellent immobilization effect. However, limited studies have focused on the synthesis of geopolymer based adsorbent for heavy metal adsorption by utilizing industrial sludge. Thus, the aim of this research was to develop metakaolin (MK) based geopolymer adsorbent with incorporation of two types of industrial sludge (S1 and S3) that could be employed as an adsorbent for removing copper (Cu2+) from aqueous solution through the adsorption process. The effects of varied solid to liquid ratio (S/L) on the synthesis of metakaolin/sludge based geopolymer adsorbent and the removal efficiency of Cu2+ by the synthesis adsorbent were studied. The raw materials and synthesized geopolymer were characterized by using x-ray fluorescence (XRF), x-ray diffraction (XRD), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) and micro XRF. The concentration of Cu2+ before and after adsorption was determined by atomic absorption spectroscopy (AAS) and the removal efficiency was calculated. The experimental data indicated that the synthesized geopolymer at low S/L ratio has achieved the highest removal efficiency of Cu2+ about 99.62 % and 99.37 % at 25 %:75 % of MK/S1 and 25 %:75 % of MK/S3 respectively compared to pure MK based geopolymer with 98.56 %. The best S/
      2  8