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Sainteknol : Jurnal Sains dan Teknologi
Published by Universitas Negeri Semarang
ISSN : -     EISSN : 25273604     DOI : https://doi.org/10.15294/sainteknol
Core Subject : Education,
Other
Sainteknol published a scientific paper on the results of research and studies in the field of science and technology. Published biannually in June and December contained the writings lifted from the results of research and critical-analysis study in science and technology.
Arjuna Subject : Umum - Umum
Articles 5 Documents
 1 
Search results for , issue "Vol. 22 No. 1 (2024): June 2024" : 5 Documents clear
Effervescent Powder Formulation of Ethanol Extract of African Leaves (Vernonia amygdalina) as an α-amylaseInhibitor Norainny Yunitasari; Nasyanka, Anindi Lupita; Luthfi, Sania Al; Ramadhanti, Nadya; Zulfiyana, Lindah Isna
Sainteknol : Jurnal Sains dan Teknologi Vol. 22 No. 1 (2024): June 2024
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v22i1.2478

Abstract

Vernonia amygdalina or African leaves are reported to have many biological activities, including antidiabetic. However, there are still many people who have not used this plant as an antidiabetic treatment. This research aims to create a medicinal preparation formula in effervescent form with the main ingredient being African leaves. Testing of the dosage formula includes organoleptic tests, water content, pH, and dispersing time. The research results showed that one of the three formulas had better stability after 7 days of storage. After 7 days of storage, the color of the formula became lighter, the pH value changed slightly (7-8), the water content was 2.3% and the dispersion time was 2.00 minutes. This formula can be used as input for further research regarding testing its activity as an antidiabetic through inhibiting alpha-amylase in vitro.
Synthesis of Glycerol Monooleate with MgO-Impregnated Natural Zeolite Catalyst Mukti, Nur Indah Fajar; Putri, Avicenna Mustika; Nur, Wahidah; Arobi, Ibnu; Arifa, Muhammad Ridho
Sainteknol : Jurnal Sains dan Teknologi Vol. 22 No. 1 (2024): June 2024
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v22i1.5441

Abstract

Glycerol Monooleate (GMO) is synthesized via esterification, which involves the reaction between glycerol and oleic acid to yield monoglyceride esters. The esterification reaction is intrinsically slow, requiring the use of a catalyst to decrease the activation energy. The catalyst used in this study is a naturally occurring zeolite catalyst that has been altered through acid treatment and impregnation with Mg(NO3)2, and then subjected to calcination to convert it into MgO. Typically, this research consists of two steps: an initial phase where a natural zeolite catalyst is altered, followed by a subsequent phase where glycerol monooleate production. This study investigates the effects of different variables on the reaction. The variables include temperature (140–180oC), catalyst loading (3-10 %weight), glycerol to oleic acid ratio (2:1, 3:1, 4:1), reaction time (0–180 minutes), and stirring speed (125-525 rpm). The research results demonstrate that the highest conversion rate was achieved with a temperature of 180oC, a catalyst concentration of 10%, and a reactant ratio of 3:1 (glycerol to oleic acid). The ideal response time was found to be 120 minutes. The reaction kinetics can be estimated by employing a pseudo reaction equation that follows a first-order rate law. The rate constant, represented by k', can be approximated using the Arrhenius equation. The reaction has an activation energy of -18.64 kJ.mol-1, and the value of A is 1.41 cm3.g-1.minute-1.
Experimental Investigation on Reduction of High Combined Water Contained Iron Ore by Ammonia-Methane-Mixed Gas Kurniawan, Ade; Iwamoto, Itsuki; Kashiwaya, Yoshiaki; Nomura, Takahiro
Sainteknol : Jurnal Sains dan Teknologi Vol. 22 No. 1 (2024): June 2024
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v22i1.7215

Abstract

Reducing CO₂ emissions in the steel industry, which contributes 7% of global emissions, is crucial. Ammonia, as a hydrogen-based reducing agent offers one promising solution to address the decarbonization challenge in primary ironmaking process due to its high hydrogen storage density and ease of transport. However, for subsequent steelmaking process, the lack of carbon in the reduced ore from the ammonia-hydrogen iron reduction system must be addressed. In this study, we reduced iron ore using an ammonia-methane mixed reducing gas to introduce carbon into the reduced ore, from the raw material of porous ore prepared from a high combined water, goethite ore. We varied the reduction conditions to investigate how the reaction and carbon content would change, aiming to optimize the reduction process and enhance carbon content in the reduced iron.  The results show that ammonia is primarily consumed for iron reduction, facilitated by hydrogen from its decomposition, while methane decomposes into carbon and hydrogen. Methane decomposition begins around 800°C, significantly increasing the ore's carbon content. Higher temperatures accelerate both reduction and carbon incorporation. The ammonia-methane mixing ratio influences reduction efficiency and carbon content, with a higher ammonia ratio expediting these processes. At 850°C, a 1:1 ammonia-methane mixture yields higher carbon content than higher ammonia ratios. This study highlights the potential of ammonia-methane mixed gases for sustainable steel production by enhancing the reduction and carbonization of high-CW-content iron ores.
Cr(VI) Removal Using A Dual Chamber Microbial Fuel Cell Ferdinand, Julian; Yuniarto, Adhi
Sainteknol : Jurnal Sains dan Teknologi Vol. 22 No. 1 (2024): June 2024
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v22i1.7752

Abstract

Chromium ions is notably a hazardous heavy metal due to its toxic and carcinogenic nature, particularly in its hexavalent form, Cr(VI). One of the major Cr(VI) pollution source is from electroplating industry effluent, which may contain high concentrations that pose a risk of contamination of aquatic and soil ecosystems if not treated carefully. One of the alternative method known to be able to treat Cr(VI) wastewater is by using microbial fuel cell (MFC). This research focused on on the removal of Cr(VI) from synthetic electroplating wastewater using a 4L dual-chamber MFC under fed-batch condition, as well as investigating the impact of mixed liquor suspended solids (MLSS) and chemical oxygen demand (COD) concentrations to its performance. Observed parameters include the efficiency of Cr(VI) removal and power density. Septage sludge and acetate were both used as biomass and substrate source respectively. Based on this research, it can be concluded that the highest Cr(VI) removal efficiency and power density were achieved using specific MLSS and COD concentration that resulting in F/M ratio of 0,459 to 0,489 gCOD/gMLSS. From initial Cr(VI) concentration of 50 mg/L, the highest removal was obtained by MFC running with initial MLSS and COD concentrations of 3.500 and 1.500 mg/L respectively, achieving 62,17% over 312 hours. This setup also produced the highest power density of 48,22 mW/m².
Optimization of Alkaline Water Production from Rainwater through Electrolysis Method: Effect of Voltage and Time on pH and TDS Rinda Erliana, Savira; Isnina Noor Ubay; Pangestu, Indra Sakti; Atik, Moh. Umar Dani; Wafa, Almas Diqya
Sainteknol : Jurnal Sains dan Teknologi Vol. 22 No. 1 (2024): June 2024
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v22i1.12507

Abstract

Alkaline water is known to have health benefits due to its higher pH than ordinary water. In this study, the production of alkaline water from rainwater using electrolysis method was optimized, with variations in voltage and time to evaluate its effect on pH and Total Dissolved Solids (TDS). The experiment involved three voltage levels (12 Volt, 24 Volt, and 36 Volt) and three time intervals (10 minutes, 20 minutes, and 30 minutes). The results showed that increasing the voltage and electrolysis time contributed significantly to the increase in water pH, which reached the highest value at 36 Volt for 30 minutes. However, increasing the voltage and time also increased the TDS value linearly, which can affect the water quality if it exceeds a certain limit. This study concludes that the optimal voltage for producing alkaline water with suitable pH and TDS is 24 Volt with an electrolysis time of 20 minutes. Thus, this method offers an efficient and simple solution to produce alkaline water from rainwater, which could potentially benefit public health in areas with limited access to high-quality drinking water.

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