Jurnal Teknik Kimia USU

Esterifikasi dan Transesterifikasi Minyak Kelapa Sawit Off-grade Menjadi Biodiesel Menggunakan Katalis Barium Hidroksida

Nurfatihayati — 2025-03-27

This research aimed to produce biodiesel from off-grade palm oil using barium hydroxide (Ba(OH)₂) catalyst. The free fatty acid (FFA) content in off-grade palm oil is quite high, so the biodiesel production process is carried out in two-stages, i.e. esterification and transesterification. The esterification of off-grade palm oil (500 mL) was carried out at 60 ^oC for 1 hour, methanol:oil molar ratio of 12:1, stirrer speed of 400 rpm, and 1 wt-% sulfuric acid (H₂SO₄) as the catalyst. Next, the transesterification process used a methanol:oil molar ratio of 9:1, stirrer speed of 400 rpm, for 2 hours with the variation of temperatures (50, 60, and 70 ^oC) and Ba(OH)₂ catalyst amounts (1, 2 and 3 wt-%). The best result was obtained with 60 ^oC and Ba(OH)₂ catalyst amount 3 wt-%. Based on Gas Chromatography-Mass Spectroscopy (GC-MS) analysis, the best yield of fatty acid methyl ester was 98.97%, with major components being 40.87% palmitic acid and 35.87% oleic acid. The characteristics of biodiesel produced were density of 860.46 kg/m³, viscosity of 4.08 mm/s², flash point of 145 ^oC and acid value of 0.457 mg KOH/g biodiesel.

Pengaruh Jumlah Sel Elektroda Terhadap Produksi Gas Hidrogen dengan Proses Elektrolisis sebagai Sumber Energi Fuel Cell

Erlinawati — 2025-03-27

Hydrogen is an environmentally friendly, carbon-free renewable energy source that can be generated through reactions with oxygen to produce electricity. One method of producing hydrogen is via water electrolysis. The aim of this study was to determine the optimal conditions for hydrogen gas production, specific energy consumption, and the use of hydrogen gas as an energy source for Proton Exchange Membrane (PEM) fuel cells, using potassium hydroxide (KOH) at concentrations of 0.1 M, 0.2 M, 0.3 M, and 0.4 M. The electrolysis process was conducted at a voltage of 10 volts for 30 minutes. The results showed that the highest hydrogen gas production, 0.8927 L, was achieved with 18 electrode cells and a KOH concentration of 0.3 M. The optimal specific energy consumption was 33,269 joules under the same conditions. The maximum efficiency of the PEM fuel cell was 47.25%, while the minimum efficiency was 44.80%

Karakterisasi Adsorben dari Limbah Pelepah Kelapa Sawit Teraktivasi Natrium Hidroksida untuk Adsorpsi Mangan

Titien Sara — 2025-03-27

The use of heavy metals including manganese (Mn) in various industrial applications such as mining and metal processing has triggered water pollution and caused a negative impact on human health. This study aims to evaluate the adsorbent properties activated by sodium hydroxide from oil palm frond waste for Mn(II) adsorption from the water via a fixed-bed column at flow rates of 5, 10, and 15 mL/min. The morphology analysis exhibited high pore development in the adsorbent after the activation process using sodium hydroxide. Similar to the results of functional group analysis, the activated adsorbent indicated an increase in oxygen-containing functional groups that are beneficial aspects in the adsorption process. In the continuous adsorption applications, a flow rate of 5 mL/min presented an optimum adsorption capacity of 36.58 mg/g compared to flow rates of 10 mL/min and 15 mL/min: 28.94 mg/g and 22.07 mg/g, respectively. The findings of the present work denote the utility and effectiveness of oil palm frond waste as an eco-friendly raw material for the fabrication of adsorbent with relatively favorable properties for Mn(II) adsorption.

Sintesis dan Karakterisasi Edible Film Berbahan Dasar Limbah Kulit Kopi dengan Penambahan Gliserol dan Sorbitol sebagai Plasticizer

Evita Wahyu — 2025-03-27

Edible film merupakan kemasan ramah lingkungan (biodegradable) dan bersifat edible (bisa dikonsumsi). Bahan penyusun utama edible film adalah hidrokoloid (polisakarida), lipid dan komposit keduanya. Salah satu jenis polisakarida berpotensi tinggi dan sedang menjadi pusat perhatian para peneliti untuk dijadikan edible film adalah pati. Namun edible film bersifat keras dan mudah rapuh sehingga perlu penambahan plasticizer untuk memperbaiki kelemahan tersebut. Pada penelitian ini digunakan campuran plasticizer gliserol dan sorbitol dengan perbandingan campurannya terhadap bahan baku 10%, 30%, 50% dan 70% (v/b pati) dan variasi konsentrasi gelatin 2 g, 4 g dan 6 g. Pati yang diekstrak dari kulit kopi memiliki kadar air 16% dengan persentase rendemen sebesar 4,39%. Hasil karakteristik edible film terbaik adalah variasi konsentrasi campuran plasticizer 10% dan konsentrasi gelatin 6 g dengan nilai kelarutan dalam air yang dihasilkan 71,37%, ketebalan 0,07 mm, kuat tarik 6,66 MPa, elongasi 22,93% dengan laju permeabilitas terhadap uap air sebesar 0,00433 g/m²s.

Adsorpsi Ion Amonium dari Larutan Encer Menggunakan Zeolit Alam Sarulla Termodifikasi KCl

Amir Husin — 2025-03-27

This study aims to evaluate the effectiveness of KCl-modified Sarulla natural zeolite in removing ammonium ions from aqueous solutions. The zeolite was modified by soaking in 0.5 M (ZA05) and 1.5 M (ZA15) KCl solutions for 24 hours at a solid/solvent ratio of 1:3 (weight/volume). The adsorption process was conducted in batch mode using an orbital shaker at a speed of 100 rpm, with contact times ranging from 0 to 210 minutes. The initial ammonium ion concentration was 100 mg/L, and the analysis was performed using a UV-visible spectrophotometer. The results showed that ZA05 and ZA15 adsorbents achieved ammonium ion removal efficiencies of 14.62% and 12.29%, respectively. Adsorption isotherm analysis using the Langmuir and Freundlich models demonstrated a good fit with the equilibrium data, with ZA15 exhibiting a higher maximum adsorption capacity than ZA05. This study confirms the potential of KCl-modified Sarulla natural zeolite as an effective adsorbent material for wastewater treatment.

Pembuatan Pengawet Alami Ikan Baronang (Siganus vermiculatus) dari Kayu Secang (Caesalpinia sappan L.) Menggunakan Ekstraksi Berbantu Gelombang Ultrasonik

Dea Syifa Fitriani — 2025-03-27

This research aims to make a natural preservative of secang wood against baronang fish. The active flavonoid compounds of secang wood can function as antioxidants, antimicrobials, and antibacterials. Secang wood extract is obtained by ultrasonic extraction with a 60% ethanol solvent. Variable temperature and extraction ratio are the most optimal at 50 °C and a ratio (w/v) of 1:20. The extracts obtained were analysed for total phenolic levels, antioxidant levels, water content, and ash content. The extract is then used as a baronang fish preservative with a concentration of 600 ppm and 1200 ppm at room temperature and refrigerator. The result is a phenolic content of 2,24 mgGAE/g, a water content of 38,96%, an ash content of 0,65%, and an antioxidant content of 109,25 ppm. Preservation results were analysed total plate number at 3 hours, 6 hours, and 9 hours, as well as the average microbial growth at 9 hours of incubation. The result exceeds the quality standard of fresh fish SNI 2729:2013, which is 5,70 CFU/g. The longer the storage time of baronang fish, the more microbes grow, which is closely related to organoleptic analysis, which decreases its freshness rate.

Inovasi Edible Coating Buah Mangga Berbasis Kitosan Kulit Udang dengan Aditif Ekstrak Daun Asam Jawa sebagai Antimikroba

Deska Rizki Pratama — 2025-03-27

Edible coating is a thin layer that can be consumed which protects the surface of the fruit from environmental influences. This study evaluates the effectiveness of shrimp shell chitosan-based edible coating with tamarind leaf extract as an antimicrobial, along with glycerol and tween 80, in preserving mango quality during 15 days of storage. The variables evaluated were the concentration of tamarind leaf extract (0.5, 1.0, and 1.5%) and mango storage duration (0, 3, 6, 9, 12, and 15 days). While the amount of chitosan used was constant. The parameters measured included total microbial count, weight loss, fruit skin color, total soluble solids, titratable acidity, and vitamin C content. The results showed that the combination of shrimp shell chitosan and tamarind leaf extract as an antimicrobial significantly reduced the degradation of mango quality, with the 0.5% concentration of tamarind leaf extract being the most effective in maintaining quality and extending shelf life of mango until 15 days.

Karakteristik Bioadsorben Limbah Ikan dengan Aktivator Kalsium Hidroksida (Ca(OH)2)

Dodi Satriawan — 2025-03-27

This research aims to conduct an initial analysis of the characteristics of bioadsorbent from fish waste which will be used as a pollutant adsorption. Fish waste was obtained from Tempat Pelelangan Ikan (TPI) in Cilacap district, Central Java. The fish waste obtained is dried by drying with solar thermal for 2 – 3 days. The carbonization process of fish waste is carried out by pyrolysis at a temperature of 550 ^oC for 4 hours until fish waste charcoal is produced. Charcoal is ground to 100 mesh size. The charcoal was then weighed 50 g and activated with 1 L of 5% Ca(OH)₂ at a temperature of 70 ^oC with stirring at 350 rpm for 2 hours; 4 hours; and 6 hours. Analysis of characteristic bioadsorbent refers to SNI 06-3730-1995. Bioadsorbent from fish waste activated at an activation time of 6 hours has the best characteristics in terms of water content and ash content of 2,75% and 20,2% respectively, while the best characteristics in terms of volatile matter content and iodine absorption capacity are found in bioadsorbent without activation of 44,33% and 1.250,46 mg/g respectively.

Penyediaan Biofilm Berbasis Pektin Kulit Buah Cempedak (Artocarpus champaden L.) Terisi Carboxymethyl Cellulose dengan Variasi Konsentrasi Gliserol Untuk Menurunkan Susut Bobot Buah Mangga

Fachreza Amri Batu Bara — 2025-03-27

Cempedak peel contains 38.85% pectin compounds and has the potential to become biofilm raw material. The characteristics of pectin-based biofilm can be improved by the addition of a glycerol plasticizer. This study aims to determine the effect of variations in glycerol concentration (0%; 3%; 5%; 7% and 9%) on biofilm charactersitics and biofilm application on the shelf life of mango fruit. Pectin was extracted using 5% citric acid at 85°C or 90 minutes. Biofilms were applied on mango fruit for 8 days. Analysis of pectin compounds showed a yield 22.09%; ash content 7.40%; equivalent weight 588.235 mg; methoxyl content 6.20%; galacturonic acid content 36.12%. Analysis of physical properties and biofilm application on mango fruit showed a density value of 2.833 g/mL; water solubility 79.41%; mango weight loss of 33.47%; and a deacrease in vitamin C of 5%. SEM-EDX analysis showed the pectin particles were homogeneous fine grains and dominated by the element of oxygen (O) 88.84%. FTIR analysis of cempedak fruit peel pectin and biofilm showed functional groups of O-H; C-H (methyl); C=O; C-O; C-C.

Pemanfaatan Sampah Plastik Multilayer, Styrofoam dan Oli Bekas untuk Pembuatan Paving Block

Royani — 2025-03-27

Plastic is an essential material in our daily lives. This study identifies that among various types of waste, multilayer plastic and styrofoam are one of the most difficult to manage optimally. One alternative to reduce this problem is to use waste as a mixture material for paving blocks. The composition of multilayer plastic and styrofoam used in this study were 65%:35%, 55%:45%, 45%:55%, and 35%:65%.This research only produced paving block samples that passed the visual test, size test, and average water absorption test. However, none of the samples passed the compressive strength, abrasion resistance, and sodium sulfate resistance tests according to the SNI 03-0691-1996 standards. Meanwhile, the water absorption test results for the 65%:35% and 55%:45% multilayer plastic-styrofoam samples met the quality standard C (for pedestrian use), while the 45%:55% and 35%:65% samples met the quality standard B (for parking equipment use).