Jurnal Teknik Kimia USU

Pengaruh Suhu Ekstraksi dan Kecepatan Pengadukan terhadap Karakteristik Crude Ekstrak Stevia

2024-07-03T18:25:02+07:00

Stevia is a natural sweetener that is 250-300 times sweeter than sucrose and is low in calories. Stevia sweeteners are obtained from the extraction of stevia leaves. This study aims to determine the effects of temperature and stirring speed on the characteristics of crude stevia extract (yield, brix value, and IR spectrum). Maceration extraction was conducted with 70% ethanol for 1 hour, varying the temperature (28 ℃, 40 ℃, 55 ℃) and stirring speed (0 rpm, 50 rpm, 100 rpm, 150 rpm). The results showed that a temperature of 40 ℃ produced the highest yield at each stirring speed. The yield increased with the increase in stirring speed at each extraction temperature. The highest brix value was obtained at 55 ℃ and a stirring speed of 150 rpm. The IR spectrum results showed that the functional groups in the crude stevia extract were almost identical to those in commercial stevia.

Pengaruh Waktu Iradiasi Ultrasonik dengan Aktivasi Kalium Hidroksida terhadap Sifat Fisis Karbon Aktif dari Serbuk Karet End Life Tire

2024-01-30T11:37:24+07:00

Processing End Life Tire (ELT) rubber powder into activated carbon is an alternative for handling tire waste. One way to improve physical properties such as proximate characteristics, surface area and pore diameter of activated carbon is through chemical activation assisted by ultrasonic irradiation. This research aims to determine the effect of ultrasonic irradiation time with potassium hydroxide (KOH) activation on the quality of ELT rubber activated carbon. Activated carbon was synthesized and activated using 30% KOH at various ultrasonic irradiation times, namely 0 minutes, 15 minutes, 30 minutes, 45 minutes and 60 minutes. Based on the characterization results, activated carbon with an ultrasonic irradiation time of 30 minutes is the active carbon that has the most superior properties. The proximate characteristics of activated carbon meet the active carbon quality requirements of SNI 06–3730–1995 and have the highest surface area, namely 401.11 m^2/g and pore diameter of 2.1652 nm, which is included in the mesoporous structure category so that it has the potential to be applied as an adsorbent for heavy metals from contaminated fluid.

Pembuatan Sabun Transparan Berbasis Minyak Kelapa dengan Penambahan Ekstrak Buah Pedada (Sonneratia caseolaris) sebagai Bahan Antioksidan

2022-11-30T13:06:27+07:00

Mangrove Apple (Sonneratia caseolaris) is a fruit native from tropical area that has antioxidant activity. This study aims to produce transparent soap with pedada fruit antioxidant enhancing agents and the observation of transparent soap quality in accordance with SNI 03-3532-1994 and antioxidant activity of transparent soap. Research began with pre-treatment process, namely extraction of mangrove apple enhancing agent by maceration and infundation method using methanol and water solvent. The obtained extracts were then added as variation of coconut oil soap production formula. The obtained soaps were then tested for free alkali rate, free fatty acid rate, moisture content, foam stability, pH and antioxidant activity by DPPH method. The antioxidant activity of the obtained soap shows that with the formulation by 0.5 g of methanol maceration extract of mangrove apple resulted in soap with IC50 antioxidant activity of 122.30 μg/mL.

Transesterifikasi In Situ Minyak Biji Pepaya Menggunakan Ko-pelarut Tetrahidrofuran: Pengaruh Waktu Reaksi dan Penggunaan Katalis Natrium Hidroksida

2024-06-07T13:40:14+07:00

The papaya seed oil is a non-food oil that can be used as raw material for biodiesel. The transesterification process using oil as raw material requires long process stages so it is not efficient. In situ transesterification with a co-solvent is an alternative to overcome this problem. This research aims to obtain optimum conditions for the in situ transesterification reaction of papaya seed oil with THF co-solvent. The research operating conditions included stirring speed 450 rpm, reaction at room temperature, oil:methanol molar ratio = 1:101.39, catalyst:oil molar ratio = 0.5:1, oil:THF molar ratio = 1: 67.85, reaction time are 3, 8, 13, 18, 23, 28 minutes and reactions with and without a NaOH catalyst. The best research conditions were obtained in the in situ transesterification reaction of papaya seed oil with THF co-solvent using a NaOH catalyst at a reaction time of 33 minutes, producing a crude yield of 74.38% and methyl esters concentration of 98,036.4 ppm and physical properties of biodiesel that met SNI 7182-2015, namely density 0.89 g/mL and acid number 0.44 mg KOH/g sample.

Pengurangan Nilai COD pada Effluent Fermentor Biogas UASB-HCPB dengan Memanfaatkan Mikroalga Chlorella vulgaris

2024-07-18T09:26:08+07:00

Palm oil mill effluent (POME) is the main waste generated from the palm oil industry. LCPKS has a COD level of 57,000-60,400 mg/L. High levels of COD can harm the environment. LCPKS treatment techniques generally use a combination of anaerobic and aerobic waste treatment methods. The anaerobic process has been conducted using a UASB-HCPB reactor. But, the COD levels of anaerobic results have not reached the quality standards so that further processing is needed. Microalgae have the potential to reduce contaminant levels in wastewater. Chlorella vulgaris microalgae is a microalgae that is widely used in wastewater treatment. This study utilized Chorella vulgaris in reducing the COD levels of the effluent of the UASB-HCPB biogas fermentor with variations in lighting intensity and variations in the ratio of effluent to microalgae. It was found that the lighting intensity of light:dark (24:0) hours provided optimal microalgae growth so as to provide the best COD reduction with a COD reduction efficiency of 87.5%. The ratio of microalgae to effluent of 1000 mL: 500 mL showed the best COD reduction with an efficiency of 93.75%.

Pengaruh Konsentrasi Enzim, Ragi, dan Lama Fermentasi terhadap Pembuatan Bioetanol Berbahan Baku Chlorella pyrenoidosa

2024-03-13T20:27:00+07:00

The demand for energy is inversely proportional to the current amount of energy in Indonesia. In order to face this problem, it is necessary to develop renewable energy sources. This study was conducted to analyze enzymes effect in the Chlorella pyrenoidosa hydrolysis, analyze yeast effect and the fermentation time of Chlorella pyrenoidosa on the bioethanol produced. The variables used are variation of α-amylase enzyme concentration of 25%, 35%, 45% (v/w), and variation of yeast concentration of 5%, 10%, 15% (w/v) and fermentation time of 7, 9, 11 days. From the analysis conducted, the highest glucose content was 13.119%, which was in the variation of 45% (v/w) α-amylase enzyme concentration. The amount of enzyme concentration used was in accordance with glucose production. The highest bioethanol was obtained with a sample involving 10% (v/b) yeast fermented for 9 days, which amounted to 27%.

Pengaruh Urutan Pencampuran Pemlastis pada Komponding Karet Terhadap Kinetika Vulkanisasi Menggunakan Model Deng-Isayev dan Kamal-Sorour

2024-01-30T11:46:46+07:00

Plasticizers play an important role in the rubber industry to facilitate the dispersion of additives into rubber. This research aims to study the effect of plasticizer mixing sequence on vulcanization kinetics. This relates to its effect on printing time and energy, as well as the cost of electricity used. Compound A was made by adding plasticizer at the mastication stage and compound B was made by adding plasticizer at the masterbatch stage. Kinetic parameters were determined using Deng-Isayev and Kamal-Sorour models. The results show that the Deng-Isayev model is closer to the experimental data than the Kamal-Sorour model. Compound A has a k value (3.0635x10^-6 sec^-1) and cure index (0.8403) slightly lower than compound B with a k value 3.3511x10^-6sec^-1 and cure index 0.9260. However, the mixing order of the plasticizers did not significantly affect the vulcanization performance, either the reaction speed constant, reaction order, induction time, optimal vulcanization time, and cure index.

Penentuan Kadar Flavonoid dan Kandungan Fitokimia Ekstrak Kulit Bawang Merah (Allium cepa L) dengan Berbantukan Microwave sebagai Potensi Bahan Aktif Tabir Surya

2024-05-07T10:46:41+07:00

The skin serves as a protective barrier against dust and ultraviolet (UV) radiation. Excessive UV exposure is associated with accelerated skin aging, erythema, hyperpigmentation, and carcinogenesis. This study aimed to quantify flavonoid concentrations and characterize phytochemical constituents in shallot skin extracts for their potential as active ingredients in sunscreen formulations. Shallot skin was subjected to microwave assisted extraction using 70% ethanol as the solvent. Phytochemical screening revealed the presence of flavonoids, tannins, saponins, and alkaloids in the extract. Flavonoid content was determined via UV-Vis spectrophotometry, yielding 36.33 mgQE/g. The high flavonoid concentration observed in shallot skin extract suggests its potential efficacy as an active ingredient in sunscreen formulations.

Ekstraksi Daun Kejibeling (Strobilanthes crispus) dengan Metode Continuous Ultrasound-Assisted Enzymatic Extraction: Pengaruh Temperatur dan Konsentrasi Enzim

2024-07-18T09:29:15+07:00

Continuous ultrasound-assisted enzymatic extraction (CUAEE) method has become a promising technique for extracting bioactive compounds from plant materials. In this study, the extraction of kejibeling (Strobilanthes crispus) leaves was carried out using the CUAEE method to optimize the extract yield. The experimental design involved extraction parameters including leaf particle size (d ≤0,177 mm), ethanol concentration (50%), extraction time (180 minutes), and varying parameters such as temperature (30 °C, 40 °C, 50 °C, and 60 °C), as well as cellulase enzyme concentration of 3% and 5%. The results showed that the optimal conditions for CUAEE were achieved at a temperature of 60 °C with an enzyme-solid ratio of 5%, producing a total phenolic content (TPC) of 12,097 mg EAG/g dry leaf powder and a total flavonoid content (TFC) of 2,291 EK/g dry leaf powder. The data obtained indicate that the continuous ultrasound-assisted enzymatic extraction method has the potential for large-scale production of phenolic acids and flavonoids.

Pengaruh Variasi Ukuran Partikel pada Pembuatan Bio-Briket dari Pelepah dan Tandan Buah Kosong Kelapa Sawit

2024-08-06T09:30:14+07:00

Palm oil empty fruit bunches (EFB) and fronds are solid waste originating from palm oil processing which can be used as the main raw material for making briquettes. This is supported by its contents, namely lignin, hemicellulose and cellulose. The smaller the particle size, the greater the compressive strength of the briquette, but the burning rate will be slower because the cavity/pores of the briquette are smaller. This research aims to determine the effect of particle (mesh) size on the characteristics of briquettes which include water content, ash content, density, compressive strength and burning rate as well as to determine the best composition of a mixture of empty oil palm fruit bunches and fronds. The results of this research show that the best particle size is 70 mesh briquettes with a raw material composition of 46% EFB and 46% fronds (1:1) with 8% tapioca flour adhesive. Biobriquettes with small particle sizes have lower calorific value. The results of this research indicate that the manufacture of briquettes is in accordance with the Standard Characteristics of SNI No. 1/6235/2000.