Cd²⁺and Cr³⁺ Cation Immobilization by Using Geopolymer Based on PT. IPMOMI Fly Ash

Abstract

This study investigates the immobilization of Cd2+ and Cr3+ by using geopolymer paste based on PT. IPMOMI fly ash. The best composition of geopolimers paste was determined based on the highest magnitude of its 7 days compressive strength. Geopolymer pastes were prepared by varying SiO2/Al2O3 and Na2O/SiO2 molar ratio of the starting materials. X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were employed to examined these compositions. The molar ratio of SiO2/Al2O3 6.46 was found to produce the highest compressive strength of the resulting geopolymer paste, i.e 25 MPa and increased to 33.17 MPa by adjusting the ratio of Na2O/SiO2 to 0.65. Cd2+ and Cr3+ cations were added into geopolymers resin at the level of 1000 – 16000 ppm (mg/kg fly ash) and it was found to improve their compressive strength. The addition of 4000 ppm of Cd2+ increased the compressive strength to 38.6 MPa while the inclusion of 6800 ppm of Cr3+ reached 47.83 MPa. Further addition of cations reduced these values and the lowest compressive strength was observed on the addition of 16000 ppm of Cd2+ and Cr3+, i.e 8.65 MPa and 4.39 MPa, respectively. Leaching test was conducted by using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) and the distribution of heavy metal cations were examined by using SEM-EDX. The results showed that geopolymer pastes were able to immobilize Cr3+ at the studied level as there was no trace of Cr3+ detected after 6.5 hours of leaching. Geopolymer pastes were also found to completely immobilize Cd2+ at the level of 1000 ppm albeit the addition of 16000 ppm results in 6.26% leached out of this cation.

Unveiling the charge transfer behavior within ZSM-5 and carbon nitride composites for enhanced photocatalytic degradation of methylene blue

“…4 and Table 1 ). 36 As presented in Fig. 4a and Table 1 , all GZ samples composed of major elements such as carbon (C) and nitrogen (N) as representative elements for g-C 3 N 4 as well as silicon (Si), aluminium (Al), and oxygen (O) as representative elements for ZSM-5.…”

The Effect of Corrosive Environment on Geopolymer Concrete Tensile Strength

“…These compounds are the source of strength in the concrete with the hydration process. On the other hand, geopolymer concrete is a green technology which is currently being developed [5][6][7][8][9][10][11] for the material structure [12]. The main factor that becomes the appeal of geopolymer concrete is the polymerization process, the process of transforming material alumino-silicate oxide and alkaline activator into polysilicate product that has high mechanical strength without using cement.…”

SINTESIS GEOPOLIMER DENGAN BAHAN DASAR KAOLIN CAPKALA SEBAGAI ADSORBEN ION Pb(II) DALAM LARUTAN (SYNTHESIS OF GEOPOLYMERS WITH BASE MATERIALS KAOLIN CAPKALA AS ADSORBENT ION Pb(II) IN SOLUTION)

“…Geopolimer memiliki kuat tekan yang lebih baik daripada beton, tahan terhadap pemanasan tinggi dan tahan terhadap asam [2] . Mekanisme kimia yang terjadi antara geopolimer dengan logam adalah logam yang bereaksi dan membentuk jaringan geopolimer dimana ion logam bertindak sebagai keseimbangan muatan, dan dienkapsulasi secara fisik [3] . Ion Pb(II) ini berpartisipasi dalam polikondensasi fase gel Si/Al yang membentuk PbO di dalam jaringan geopolimer [4] .…”