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All Journal FLUIDA Jurnal Rekayasa Proses
Iwan Ridwan
Politeknik Negeri Bandung
Chemical Engineering, Chemistry & Bioengineering Chemistry Energy Engineering Environmental Science Materials Science & Nanotechnology

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SINTESIS LI-NMC MELALUI METODE SOLID STATE MENGGUNAKAN MHP DAN NISO4 SEBAGAI VARIASI SUMBER NIKEL Haryadi; Iwan Ridwan; Muhammad Salman Alfarisi; Rizky Yanuar Haz
Fluida Vol. 18 No. 2 (2025): FLUIDA
Publisher : Department of Chemical Engineering, Politeknik Negeri Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35313/fluida.v18i2.6557

Abstract

Li-NMC-based cathodes are widely developed for next-generation batteries due to their high electrochemical performance and energy density. This study focuses on synthesizing Li-NMC type NMC811 using two nickel sources Mixed Hydroxide Precipitate (MHP) and nickel sulphate (NiSO4) through the solid state method. The process involved calcination at 500°C for 5 hours and sintering at 700oC, 800oC, and 900oC for 12 hours. The aim was to analyze the effect of temperature and nickel source on the crystallinity and crystal size of Li-NMC. X-Ray Diffraction (XRD) revealed that low crystallinity was observed at 700oC due to broad and weak diffraction peaks. Sintering at 800oC improved the structure and showed the presence of a Li0.88Mn2O4 phase. At 900oC, samples showed sharp peaks and high intensity, indicating excellent crystallinity. Crystal size analysis using the Debye-Scherrer equation showed that NiSO4 samples reached 41.98 nm at 800oC, while MHP samples achieved 71.69 nm at 900oC both exceeding the commercial size of 29.56 nm. These results suggest that 800-900oC is optimal for Li-NMC synthesis, and MHP is a promising alternative nickel source.
Characterization of caffeine crystals obtained from the extraction process of green robusta coffee beans Tri Hariyadi; Ayu Ratna Permanasari; Iwan Ridwan; Bambang Soeswanto; Teguh Taufiqurohim; Unung Leoanggraini; Fania Hidayati; Renata Naomi Cinta Sedjati; Mentik Hulupi
Jurnal Rekayasa Proses Vol 20 No 1 (2026): Volume 20, Number 1, 2026
Publisher : Jurnal Rekayasa Proses

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.24765

Abstract

Robusta coffee contains a higher caffeine content, ranging from 1.6–2.4%, nearly twice as much as Arabica coffee, which contains only 0.9–1.2%. Caffeine content is widely utilized in various fields, such as pharmaceuticals and the food and beverage industry. This study aims to analyze the effect of temperature and time on the solid–liquid extraction process of green coffee beans, as well as to evaluate the effectiveness of two different solvents in the liquid–liquid extraction process for obtaining caffeine crystals. Solid–liquid extraction was carried out at temperature variations of 70°C, 80°C, 90°C, and 97°C, with durations of 30 minutes, 45 minutes, 60 minutes, 75 minutes, and 90 minutes. Liquid–liquid extraction was performed using two types of organic solvents, namely chloroform and dichloromethane. The results were analyzed by measuring caffeine purity using a melting point apparatus and high-performance liquid chromatography (HPLC) based on retention time parameters, as well as determining caffeine concentration using a UV–Vis spectrophotometer. The optimum temperature and time for solid–liquid extraction were found to be 97°C for 60 minutes. Liquid–liquid extraction yielded a caffeine content of 2.18 mg/g using chloroform, and 1.38 mg/g using dichloromethane. Based on melting point and HPLC retention time testing, the caffeine crystals obtained from liquid–liquid extraction with dichloromethane showed higher purity, with a melting point of 236°C and a retention time of 2.06 minutes. These values are close to those of pure caffeine, which has a melting point of 236°C and a retention time of 2.01 minutes, compared to the caffeine crystals obtained using chloroform.
Co-Authors Bambang Soeswanto Fania Hidayati Haryadi, Haryadi Mentik Hulupi Muhammad Salman Alfarisi Permanasari, Ayu Ratna Renata Naomi Cinta Sedjati Rizky Yanuar Haz Teguh Taufiqurohim Tri Hariyadi Unung Leoanggraini