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All Journal Indonesian Journal of Chemistry Automotive Experiences Makara Journal of Science
Arfah, Rugaiyah Andi
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Aerospace Engineering Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Chemistry Control & Systems Engineering Electrical & Electronics Engineering Energy Materials Science & Nanotechnology Mechanical Engineering

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Synthesis, Molecular Characteristics, and Antibacterial Assessment of Marine Hydroid Aqueous Extract-Based Silver Bio-nanoparticles Mandey, Fredryk; Arfan, Aulia Rhamdani; Arfah, Rugaiyah Andi
Makara Journal of Science
Publisher : UI Scholars Hub

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Abstract

This investigation aims to synthesize, analyze the molecularity, and test the ability of bacterial inhibition capability of silver nanoparticles that have been synthesized by simply mixing silver nitrate and aqueous extracts of marine natural products with and without the addition of amylum as a stabilizing agent. This research, with and without the addition of amylum as a stabilizing agent, obtained 39.0 and 55.2 mg of solids of round-shaped morphology silver nanoparticles with diameters of 87.9 and 103.0 nm., respectively. In addition, the antibacterial testing assay against Staphylococcus aureus and Escherichia coli showed some considerably good results. S. aureus with the addition of amylum had inhibition zone diameters of 8.55 and 7.45 mm, whereas without the addition of amylum had inhibition zone diameters of 7.82 and 7.22 mm. E. coli with the addition of amylum had inhibition zone diameters of 7.0 and 7.65 mm, whereas E. coli without the addition of amylum had inhibition zone diameters of 7.82 and 7.22 mm.
The Utilization of Gracilaria sp. as Raw Material for Cellulose in Cellulose Acetate-Nickel Oxide (CA-NiO) as Electrode for Energy Storage Technology Karim, Abdul; Ahmad, Ahyar; Arfah, Rugaiyah Andi; Ermawar, Riksfardini Annisa; Karim, Harningsih; Putra, Andi Erwin Eka; Putri, Suriati Eka; Negara, Satria Putra Jaya; Larekeng, Siti Halimah
Indonesian Journal of Chemistry Vol 25, No 1 (2025)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.96533

Abstract

In the modern era, electrical energy has become a significant need that drives the large consumption of fossil fuels and their environmental impacts. Supercapacitors can reduce this large consumption of natural polymers such as cellulose acetate (CA), which can be synthesized from Gracilaria sp. Composites with CA can be an environmentally friendly alternative electrode with low toxicity. The results show that the cellulose has been successfully synthesized from the algae Gracilaria sp., which was proven by FTIR spectra analysis. The results also show that supercapacitor electrodes have been successfully made where the manufactured electrodes form a composite between CA and nickel oxide (NiO), with the highest specific capacitance and specific energy values of 15.5 × 102 F/g and 13.3 × 102 Wh/kg, respectively, on the CA-NiO2 electrode, but when the NiO concentration is higher than the CA concentration the specific capacitance and specific energy decrease as shown on the CA-NiO electrode with NiO mass of 0.6 g. Thus, the materials results of this study can be applied to electric vehicles and technology that requires electricity storage in the future.
Effectiveness of HNO3 and NaOH Pretreatment on Lignin Degradation in Areca Leaf Sheath Fibre (Areca catechu L.) for Bioethanol Production Wahyuti, Wahyuti; Karim, Abdul; Arfah, Rugaiyah Andi; Zakir, Muhammad; Maming, Maming; Baharuddin, Maswati
Automotive Experiences Vol 8 No 2 (2025)
Publisher : Automotive Laboratory of Universitas Muhammadiyah Magelang in collaboration with Association of Indonesian Vocational Educators (AIVE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31603/ae.13089

Abstract

Areca leaf sheaths are underutilized waste but have a high cellulose content of 72.27%, so they can be utilized for bioethanol production. This research aims to utilize areca leaf waste for bioethanol production through acid (HNO3 5%) and alkaline (NaOH 10%) pretreatment processes, enzyme hydrolysis, and fermentation. Pretreatment using 5% HNO3 and 10% NaOH solutions is carried out because it can break down the lignin bond and release it from cellulose and hemicellulose fibers. The enzymatic hydrolysis process uses cellulase enzymes at 37 °C for 48 hours to produce glucose. Glucose content analysis uses the DNS method and UV-Vis spectrophotometry instruments because it is accurate and can detect glucose in low concentrations. The fermentation process is carried out using Saccharomyces cerevisiae as a fermentation microorganism because it has high efficiency in bioethanol production for a duration of 3, 5, and 7 days. Based on the results of the analysis, pretreatment with HNO3 5% solution reduced the level of lignin in areca leaf sheaths by 2.31%. Meanwhile, pretreatment using a 10% NaOH solution lowered lignin levels to 1.81%. Reduced sugar levels after hydrolysis after pretreatment with HNO3 5% and NaOH 10% were 25.08 mg/mL and 16.37 mg/mL, respectively. The highest concentration of bioethanol in the 5% HNO3 pretreatment was achieved on the 7th day at 16.75%, while that of 10% NaOH on the 5th day was 14.75%. This difference is influenced by the availability of fermentable sugars, where HNO3 substrates take longer to decompose by S. cerevisiae than NaOH substrates. Based on the analysis, the bioethanol contains ethanol, thus the areca leaf sheath fibre feedstock has the potential to assist in the advancement of a sustainable biorefinery process that can reduce dependence on fossil fuels and increase added value.
Co-Authors Abdul Karim Ahyar Ahmad Andi Erwin Eka Putra Arfan, Aulia Rhamdani Fredryk Mandey Harningsih Karim Maming Maming Maswati Baharuddin Muhammad Zakir Negara, Satria Putra Jaya Riksfardini Annisa ERMAWAR SITI HALIMAH LAREKENG, SITI HALIMAH Suriati Eka Putri Wahyuti, Wahyuti