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Sainteknol : Jurnal Sains dan Teknologi
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This is an Open Access Journal

Open Access journal
ISSN (Print) 0216-4566 - ISSN (Online) 2527-3604
Published by Universitas Negeri Semarang

[79 journals]

Thermal Behavior and Kinetic of Degradation of PVA and PVA/CS/AL Blend
- Authors: Retno Wulandari, Yogi Angga Swasono, Muchamad Zain Nur Ichsan, Annisa Rifathin
  Pages: 1 - 10
  Abstract: Studying thermal behavior, especially regarding the kinetics of the degradation of materials has attracted attention in this recent years because it can provide information about the stability of materials in various conditions and how the mechanism of material degradation. In this research, the thermal behavior and kinetics of thermal degradation of polyvinyl alcohol (PVA) and polyvinyl alcohol (PVA)/cassava starch (CS)/alkaline lignin (AL) with glycerol as a plasticizer were investigated and compared by the thermogravimetric analyzer. The test was carried out for samples under non-isothermal conditions in nitrogen at a single heating rate of 10 °C/min. The activation energies were calculated using Coats-Redfern, Broido, and Horowitz-Metzger methods. The results showed that PVA/0 and PVA/CS/AL had four decomposition steps with the main degradation of PVA/0 and PVA/CS/AL in the second and third decomposition steps. The first degradation of PVA/0 and PVA/CS/AL occurred at 125 °C - 270 °C with a decomposed mass of 35.94%, and 135 °C – 250 °C with a decomposed mass of 31.84%, respectively. The second degradation of PVA/0 and PVA/CS/AL was at 270 °C - 385 °C with a decomposed mass of 40.33% and 250 °C – 395 °C with a decomposed mass of 38.62%. The values of activation energies using Coats-Redfern, Broido, and Horowitz & Metger methods of PVA/0 were 57.08 KJ/mol, 64.82 KJ/mol, and 70.57 KJ/mol, respectively. The values of activation energies using Coats-Redfern, Broido, and Horowitz & Metger methods of PVA/CS/AL were 74.49 KJ/mol, 82.17 KJ/mol, and 95.65 KJ/mol, respectively. The lower activation energy indicates that degradation reactions occur more easily. PVA/CS/AL has slightly better thermal stability than PVA/0.
  PubDate: 2023-06-09
  DOI: 10.15294/sainteknol.v21i1.42675
  Issue No: Vol. 21, No. 1 (2023)
Study of Heavy Metal Content in Lola Snail (Trochus niloticus) in The
Karang Island of Central Tapanuli Regency
- Authors: Aisyah Umi Ramadhani Samosir, Rahmatsyah Rahmatsyah, Rita Juliani
  Pages: 11 - 17
  Abstract: Research on the analysis of heavy metal content in the waters of Karang Island, Central Tapanuli Regency aims to know the metal content in Lola Snail meat, sediment, and Lola Snail shells. The research method begins with taking samples of Lola snails and sediments on Karang Island and preparing the samples. Then, the samples were analyzed by AAS (Atomic Absorption Spectrometry) to determine the content of heavy metal elements in the meat of Lola Snail, followed by XRD (X-Ray Diffraction) testing to determine the content of heavy metal elements in sediments, and also testing with EDX (Energy Dispersive X-Ray) to determine the content of heavy metals in the shell. The results of the analysis on the AAS test showed that the order of heavy metal concentrations in Lola snail meat at station I was Zn > Cr > Cu > Cd > Pb, while at station II was Zn > Cu > Cr > Cd > Pb. The results of the sequence of heavy metal concentrations using XRD in sediments around Karang Island at the station I was Zn > Cr > Cu > Cd > Pb, while at station II was Zn > Cd > Cu > Cr > Pb. The results of the analysis on the shells of Lola snails using EDX at both stations showed they did not contain heavy metal elements (Pb, Cd, Cu, Cr, and Zn), but only contained O, Ca, Mg, Na, Al, and Si elements.
  PubDate: 2023-06-16
  DOI: 10.15294/sainteknol.v21i1.43387
  Issue No: Vol. 21, No. 1 (2023)
The Potential of Earthworms (Eudrilus eugeniae) in Vermicompost Production
from Vegetable Market of Waste Cabbage and Fruit Skins
- Authors: Irene Nindita Pradnya, Nadya Alfa Cahaya Imani, Maharani Kusumaningrum, Hanif Ardhiansyah, Devina Dwiyuanita Nugraha, Amaliya Fairuz Syakila
  Pages: 18 - 27
  Abstract: Traditional markets are one of the highest contributors to waste. Traditional markets can produce a lot of waste, one of the wastes with a large amount is organic waste. The alternative that can be done to deal with organic waste and can be converted into a product is to make compost using the vermicompost method. The aim of this study was to find out the length of time for composting in the manufacture of compost, to determine the optimal amount of Eudrilus eugeniae in the composting process, and to find out the optimal distribution of waste in composting. The incubation process for compost was carried out for 8 weeks, with sampling at weeks 4, 6, and 8. Sampling was carried out to analyze the macronutrient content consisting of C-Organic, nitrogen, and potassium. Content analysis was carried out using UV/VIS spectrophotometry for analysis of C-Organic content, Kjeldahl method for nitrogen content analysis, and Atomic Absorption Spectrophotometer (AAS) for potassium content analysis. The specifications for compost from organic waste are based on the Indonesian National Standard (SNI 19-7030-2004). This research resulted in C-Organic content of 6.1-8.1%, nitrogen content of 0.32-0.43%, and potassium content of 0.16-0.23%.
  PubDate: 2023-06-16
  DOI: 10.15294/sainteknol.v21i1.43485
  Issue No: Vol. 21, No. 1 (2023)
Kinetic Modelling of Liquid-Solid Extraction of Bioactive Compounds from
Ginger Waste using Subcritical Water
- Authors: Mohamad Endy Yulianto, Bakti Jos, Budiyono Budiyono
  Pages: 28 - 35
  Abstract: Kinetic modelling played a key role in the development of subcritical water extraction for bioactive compounds such as: shogaol and gingerol from ginger waste. Liquid-solid extraction kinetics could predict the extraction phenomenon and increase the efficacy of extraction process. The aim of this study was to develop a mathematical model of leaching kinetics and determine the rate constant of extraction process (k) of shogaol and gingerol in ginger pulp which is in the subcritical water phase. The research was carried out in two work stages, namely modeling and experimentation. The modeling was done by comparing three extraction kinetic models, namely pseudo first order, pseudo second order and the distribution coefficient. The model was postulated and validated with experimental data using Matlab. The subcritical water extraction process of shogaol and gingerol in ginger waste was occurred at 140 ℃ with a pressure of 3.5 bar. The extracts had been separated from raffinate and further analyzed using HPLC-MS. The results showed that the pseudo first order kinetic model described well the phenomenon of subcritical water extraction with regression values was 0.9882 for gingerol and 0.9682 for shogaol respectively. The rate constant of extraction process (k) for gingerol and shogaol were 0.1101 and 0.3130 , respectively. This showed that the shogaol extraction rate was higher than the gingerol extraction rate.
  PubDate: 2023-06-16
  DOI: 10.15294/sainteknol.v21i1.44589
  Issue No: Vol. 21, No. 1 (2023)
Production of Liquid Soap from Virgin Coconut Oil with the Active
Ingredient Citronella Oil
- Authors: Prima Astuti Handayani, Didit Rizky Aditiya, Jannatin Ockta Almaidah
  Pages: 36 - 42
  Abstract: The use of hand-washing soap is able to kill germs because it can remove oil and dirt that sticks to the hands. In making this liquid soap, active substances from nature, which is citronella oil, are used as anti-bacterial and anti-fungal agents. This study aims to study the factors that influence the response of free alkali and optimum conditions in the manufacture of liquid soap. The optimization method uses Response Surface Methodology (RSM) based on Central Composite Design. Experimental variables were carried out at reaction temperature (60-80°C), KOH concentration (30-50%), and reaction time (30-50 minutes). The results of the analysis using statistical software obtained the optimum operating conditions for the reaction time of 56,818 minutes, KOH concentration of 46,818%, and reaction temperature of 86,818°C with a free alkali value response of 0.04158%. These results meet the SNI 06-4085-1996 standard with a free alkali value below 0.1%.
  PubDate: 2023-06-28
  DOI: 10.15294/sainteknol.v21i1.44060
  Issue No: Vol. 21, No. 1 (2023)