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PublicationBiomass Waste Incorporation in La₀.₆Sr₀.₄Co₀.₂Fe₀.₈O₃-α˗Ba(Ce₀.₆Zr₀.₄)₀.₉Y₀.1O₃-δ composite cathode: effects on microstructural and physical properties(Chemistry Department, Universitas Gadjah Mada, 2025)This study explores the incorporation of rice straw as a pore-forming agent in fabricating the La₀.₆Sr₀.₄Co₀.₂Fe₀.₈O₃-α˗Ba(Ce₀.₆Zr₀.₄)₀.₉Y₀.1O₃–δ (LSCF-BCZY) composite cathode, focusing on its microstructural and physical properties. Conventional cathode materials often face challenges in balancing porosity and structural stability, with synthetic pore formers posing environmental and consistency concerns. To address these issues, rice straw was introduced into the cathode matrix at varying weight percentages, and the composites were sintered at 1000 °C. The addition of rice straw was evaluated using X-ray diffraction, scanning electron microscopy, and densitometry. The results revealed that increasing rice straw content significantly enhanced cathode porosity, rising from 5.53 to 27.74%, with a concomitant reduction in density from 1.33 to 0.93 g/cm3, while maintaining the crystalline stability of the LSCF-BCZY composite. Enhanced porosity suggests improved reactant diffusion to active sites, potentially benefiting the cell's performance in future energy applications. This work highlights the potential of agricultural waste as a sustainable and effective alternative to synthetic pore formers in cathode fabrication.
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PublicationLycopene and β‐carotene thermal degradation kinetics and colour‐antioxidant changes in gac (Momordica cochinchinensis) fruit aril paste(Institute of Food Science & Technology, 2024-02)This study investigated the impact of heating temperatures (70 °C to 90 °C for up to 14 h) on lycopene and β-carotene degradation kinetics in gac aril paste. Carotenoids extracted via low-volume hexane-assisted ultrasonic extraction revealed a first-order degradation pattern with high correlation coefficients (0.96–0.97). Lycopene degraded faster at 90 °C (k = 12.05 × 102 h−1) than at 70 °C (5.41 × 102 h−1), while β-carotene displayed relatively slower degradation. Corresponding half-life (t1/2) values for lycopene ranged from 5.75 to 12.81 h, while β-carotene displayed values of 9.48–20.2 h. β-carotene showed superior thermal stability compared to lycopene across all temperatures. Additionally, colour changes indicated decreased brightness with increasing temperature. The DPPH radical scavenging activity and FRAP values decreased during gac fruit heating. Overall, this study emphasises temperature-induced declines in lycopene and β-carotene levels in gac aril paste and offers insights into their degradation kinetics under thermal processing.
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PublicationAdsorption efficiency and photocatalytic activity of silver sulphide-activated carbon (Ag₂S-AC) composites(Elsevier B.V., 2025)Background: This study investigates the adsorption efficiency and photocatalytic activity of silver sulphide-activated carbon (Ag₂S-AC) composites derived from ground coffee waste (GCW). Methods: In this work, GCW was preceding to carbonized at 500 ± 2°C for hours and formed biochar. Then, GCW was subjected to activation using hydrochloric acid (HCl), phosphoric acid (H₃PO₄) and potassium hydroxide (KOH). The mixture was left to soak for 24 h at room temperature, followed by carbonization at 350 and 500˚C. In the meantime, the silver sulphide (Ag₂S) was synthesized by using an ion exchange method. Sodium sulphide (Na₂S) was used as sulphur source and mixed with silver nitrate (AgNO₃) and sodium citrate (NaCit) for two hours, then dried in oven at 50 ± 2°C for 10 h. Next, the carbonized AC was subsequently combined with synthesized silver sulphide, resulting in the creation of Ag₂S-activated carbon composites that functioned both as adsorbent and photocatalyst. Their capabilities as adsorbents and photocatalyst were studied by using copper ions (Cu2+) and methylene blue (MB) solution. Significance findings: Based on results, GCW and all the prepared activated carbons are in the amorphous phase, except for the Ag₂S-AC composites, where the Ag₂S peak reflection can be observed from the X-ray diffraction (XRD) pattern. GCW shows rough and dense surface morphology. The AC shows different pore sizes and structures depending on the chemical activators used, where AC-KOH shows the largest pore size (165.31 μm). The existence of micropores can be observed in all the activated carbon samples. For the adsorption of Cu2+, all samples show more than 99 % of the removal efficiency. While for photocatalytic testing, the Ag₂S-H₃PO₄ sample shows the highest degradation rate (97.7 %) of MB solutions.
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PublicationSiliceous waste material supported MOF-5 for carbon monoxide capture at low temperature(Springer Nature, 2025)This study investigated the removal of carbon monoxide (CO) by using modified metal–organic framework-5 (MOF-5) adsorbent. The incorporation of siliceous waste materials (i.e., rice husk ash (RHA) and coal fly ash (CFA)) and the effect of sonication and triethylamine (TEA) were investigated to determine their effect on CO capture performance. Experimental results showed that the combined use of sonication, TEA and the presence of siliceous waste materials in MOF-5 resulted in a significant increase in the CO adsorption capacity from 1.8 mg/g (pristine MOF-5) to 8.18 mg/g (modified MOF-5-RHA1000-CFA(2:1)-TEA/UB/b). Kinetic studies showed that the pseudo-second-order kinetic model could more accurately predict the CO adsorption on the modified MOF-5 adsorbent, suggesting that chemisorption is the main mechanism for CO capture. Characterization techniques using BET, FTIR, and SEM/EDX verified structural and compositional changes in the modified MOF-5. This study provided valuable insights into the potential of siliceous waste material supported MOF-5 for efficient CO capture, suggesting future research directions in understanding the sonication effect and optimizing synthesis conditions for improved sustainability and performance.
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PublicationAdvanced dual-wetting membrane for enhanced CO₂ capture: asymmetric hydrophobic and CO₂-philic thin film in membrane gas absorption(Korean Society of Industrial Engineering Chemistry, 2025-09)CO₂ is a major contributor to climate change, making efficient carbon capture essential for emission reduction. Membrane gas absorption (MGA) offers a cost-effective solution, with research often focusing on enhancing membrane hydrophobicity to reduce wettability. However, the potential of CO₂-philic membranes for mixed gas separation remains underexplored. This study addresses the gap by developing asymmetric wetting membranes (PVDF/EDA/GO) with a superhydrophobic side to prevent wetting and a CO₂-philic side to enhance CO₂ capture. The CO₂-philic surface was created by coating PVDF with ethylenediamine (EDA) and graphene oxide (GO). Computational analysis confirmed strong binding energy (−21.07 kcal/mol) between EDA and GO, forming a stable amine complex. The membranes displayed asymmetric wetting, with the CO₂-philic side showing a water static angle (WSA) of 49.6 ± 2.6°, and the superhydrophobic side achieved a WSA of 149.7 ± 3.3° and a water gliding angle (WGA) of 9.8 ± 1.1°. In MGA, these membranes demonstrated improved performance, with a CO₂ absorption flux of 0.0040 mol/m2s and CO₂/N2 selectivity of 6. This work highlights the promise of dual-wetting membranes for enhancing CO₂ capture in MGA systems.