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All Journal REKAYASA Jurnal Redoks Martabe : Jurnal Pengabdian Kepada Masyarakat JURNAL PENDIDIKAN TAMBUSAI Jurnal Riset Teknologi Pencegahan Pencemaran Industri Jurnal Bio-Geo Material Dan Energi Jurnal Engineering Jurnal Karya Abdi Masyarakat Jurnal Pengabdian Masyarakat Pinang Masak Jurnal Teknologi dan Inovasi Industri Pengabdian Cendekia Nata Palemahan: Journal of Environmental Engineering Innovations
Alfernando, Oki
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Religion Agriculture, Biological Sciences & Forestry Arts Humanities Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Health Professions Industrial & Manufacturing Engineering Mathematics Physics Public Health Social Sciences Other

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Journal : rekayasa

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The Effect of Temperature Variation on the Liquefaction of High-Density Polyethylene Plastic Waste Alfernando, Oki; Marpaung, Gabriel Adi Pratama
Rekayasa Vol 17, No 2: Agustus, 2024
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v17i2.24252

Abstract

This study aims to determine the comparison of oil yields obtained from processing HDPE plastic waste by comparing quantitatively and qualitatively the fuel oil produced. The processing of plastic waste into oil by pyrolysis process was carried out at a temperature variation of (400; 500; 600; 700; 800)°C for 120 minutes. In one experiment, 500 grams of plastic waste, 250 grams of dolomite catalyst, and 250 ml of H2SO4 solvent were required. This research was conducted at the Laboratory of SKL Engineering Department, Jambi University with the parameters tested including volume, mass, %-yield, density, and GC-MS analysis. The results showed that quantitatively the lowest volume, mass, and %-yield were at the 400oC temperature variation, and the highest at 500oC. At 500oC pyrolysis temperature variation, the resulting density was 0.744 grams/ml, and the results of GC-MS analysis produced carbon chains C5-C12 97.6081% (gasoline), C13 2.3919% (kerosene), and aromatic compounds contained in it amounted to 14.3786%.
Sustainable River Water Treatment Using Coffee Grounds: A Case Study on the Batanghari River Raudhatussya'rifah, Ra'ida; Heraningsih, Sarah Fiebrina; Alfernando, Oki; Widyastuti, Nita; Amelia, Dera; Meiyola, Nada Karima; Amanda, Nathasya Putri; Sakinah, Syarri; Ancel, Violetta Fanissa
Rekayasa Vol 18, No 3: Desember, 2025
Publisher : Universitas Trunojoyo Madura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21107/rekayasa.v18i3.31002

Abstract

The Batanghari River is increasingly contaminated by organic and inorganic pollutants resulting from intensive human activities, posing significant risks to both ecosystems and public health. This study evaluates the potential of spent coffee grounds—a low-cost, eco-friendly organic waste—as a biosorbent to purify the river water, specifically focusing on the removal of soluble contaminants measured by Total Dissolved Solids (TDS). The coffee grounds were prepared via thermal activation (110 °C for 30 min) and systematically tested in a batch adsorption system using dosages of 1, 2, and 3 grams to determine the optimal dosage for water quality improvement. The treatment demonstrated high efficacy across multiple water quality parameters. The adsorbent achieved an outstanding turbidity removal efficiency of 91.96%, effectively eliminating suspended particles. The optimal reduction in TDS was recorded at 4.9 mg/L using the 3-gram dosage, confirming success against soluble contaminants. Concurrently, the pH level increased from 6.65 to 8.16 at the 2-gram dose, reflecting improved water neutrality, and physical observations confirmed the murky, foul-smelling water became visibly clearer and odorless. Isotherm analysis revealed that the adsorption process is governed by the Langmuir model, confirming a favorable monolayer adsorption mechanism. This is evidenced by a maximum adsorption capacity (Qmax) of 10.50 mg/g and a separation factor (RL) of 0.21. These results robustly establish spent coffee grounds as a highly accessible and sustainable solution for environmental remediation, offering a viable pathway for restoring river water quality while utilizing agricultural waste. 
Co-Authors Abiyoga, Nurza Purwa Ade Adriadi Ade Nurdin Akbar, Firdaus Aldillah Herlambang Alya Deenanti, Dara Amanda, Nathasya Putri Amelia, Dera Ancel, Violetta Fanissa Ayu Lestari, Rara Azzahra, Nadila Putri Badariah Badariah Bahar, Fetty Febriasti Diah Riski Gusti Dila Oktarise Dwina Dufan Saragih, Juro DWI RAHMAWATI Dwina, Dila Oktarise Dyah Kumalasari Ermadani Ermadani Ezra Sitorus, Fajar Feerzet Achmad Fetty Febriasti Bahar Galih Prabasari, Ira Galih, Ira Haleza, Nur Hariestya Viareco Haviz, M Hutagalung, Winny Laura Christina Ilman, Dzulfanur Intan Lestari Lestary, Rara Ayu Lince Muis Lince Muis Manurung, Pandapotan Maruli Tua Marpaung, Gabriel Adi Pratama Mauliza Duana, Chindy Meiyola, Nada Karima Mundarti, Sri Nazarudin Okta Priadi Oktarise Dwina, Dila Pane, Patricia Permata Putri Prabasari, IG Prabasari, Ira Galih Putri, Fiona Dehansa Rahma Amalia Rainiyati Rainiyati Raudhatussya'rifah, Ra'ida Raudhatussya’rifah, Ra’ida Revis Asra Rinaldi Rinaldi Rosmawati Sipayung Sakinah, Syarri Sarah Fiebrina Heraningsih Shafira, Rizka Simamora, Syintia Laura Sinurat, Riristiani Sipayung, Rosmayati Stevence Manalu, Laurentsius Suryadi, Hadistya Suryadri, Hadistya Syafutra, Muhammad Anggih Viareco, Hariestya Widyastuti, Nita Yuhermita, NM