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All Journal ALCHEMY Jurnal Penelitian Kimia
Yuniawan Hidayat
Sebelas Maret University
Chemical Engineering, Chemistry & Bioengineering Chemistry Energy Environmental Science Materials Science & Nanotechnology

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Preparation and Optimization of Coal Fly Ash-Based Geopolymer and Its Application as an Adsorbent for Basic Yellow 2 and Methylene Blue Dyes Eddy Heraldy; Edi Pramono; Yuniawan Hidayat; Khoirina Dwi Nugrahaningtyas; Angel Maydeleine; Intan Dwi Rahmadani
ALCHEMY Jurnal Penelitian Kimia Vol 22, No 1 (2026): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.22.1.98784.254-263

Abstract

The preparation of geopolymer from coal fly ash (CFA) solid waste of Jepara PLTU has been carried out by activating CFA using a 10 M NaOH solution and Na2SiO3. Characterization of CFA and geopolymer using X-ray fluorescence (XRF), X-ray diffractometer (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform Infra-Red (FTIR) spectroscopy. The adsorption process was studied under parameters including pH, geopolymer mass, contact time, and initial adsorbate concentration. The optimum conditions for the adsorption process of basic yellow 2 dye with fly ash-based geopolymer were optimum at solution pH of 11; adsorbent mass of 0.15 g; contact time of 120 minutes; and initial concentration of 80 ppm, while methylene blue adsorption was at solution pH of 11; adsorbent mass of 0.15 g; contact time of 120 minutes; and initial concentration of 60 ppm. Coal fly ash, a solid waste product from the Jepara PLTU, can be used to produce geopolymers through geopolymerization in the presence of activators such as NaOH and Na₂SiO₃. The adsorption capacities of these geopolymers for basic yellow 2 and methylene blue dye solutions are 26.55 and 19.825 mg/g, respectively.
Synthesis of Ni2+/Natural Zeolite by Electro-Ion Exchange I F Nurcahyo; Fitria Rahmawati; Lisa Agustina Nurlaila; Yuniawan Hidayat; Eddy Heraldy; Khoirina Dwi Nugrahaningtyas; Taufiiq-Yap Yun Hin
ALCHEMY Jurnal Penelitian Kimia Vol 22, No 1 (2026): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.22.1.80180.241-245

Abstract

Electro-ion exchange was carried out to synthesize Ni2+/natural zeolite at room temperature using various concentrations of Ni(NO3)2 of 0.05, 0.1, 0.15, and 2.0 M, zeolite wetting times of 0 and 24 hours, electrolysis times of 1, 2, and 3 hours, and voltages of 7.5, 15, and 28.4 V. The amount of Ni2+ that can be impregnated in the zeolite was monitored with Atomic Absorption Spectroscopy (AAS). The Ni2+/zeolite formed was characterized for its total acidity. The optimum conditions for this process are 28.4 V, 3 hours, and 0.1 M Ni(NO3)2. Under these optimum conditions, the Ni2+ content of the natural zeolite was 0.04 mmol/g, with a total acidity of 2.5 mmol/g. The increasing trend in the amount of Ni2+ content matched the trend in the total acidity. The synthesized Ni²⁺/natural zeolite is expected to be applied as a catalyst in reactions such as hydrogenation and hydrocracking.
Co-Authors Angel Maydeleine Eddy Heraldy Edi Pramono Fitria Rahmawati I F Nurcahyo Intan Dwi Rahmadani Khoirina Dwi Nugrahaningtyas Lisa Agustina Nurlaila Taufiiq-Yap Yun Hin