Indonesian Journal of Chemical Science and Technology (IJCST)
Indonesian Journal of Chemical Science and Technology (IJCST) is published by The Chemistry Department of Mathematics and Natural Sciences Faculty, Universitas Negeri Medan (UNIMED) Indonesia. This scientific periodical specializes in the study of the Multidisciplinary Chemistry Field, including Pure Chemistry and Applied Chemistry. The journal publishes original research and review which submissions on original advances in the understanding of Chemical application and Engineering areas, are welcome. Indonesian Journal of Chemical Science and Technology (IJCST) has been accredited for 4th grade (SINTA 4) by the Ministry of Research, Technology, and Higher Education of the Republic of Indonesia since Vol. 6, No. 1, 2023 according to the decree No.152/E/KPT/2023. The following are the field within the scope of Indonesian Journal of Chemical Science and Technology : Basic Chemistry Analytical Chemistry Physical Chemistry Organic Chemistry Inorganic Chemistry Biochemistry Applied Chemistry Chemical Engineering Indonesian Journal of Chemical Science and Technology has become a CrossRef Member and all articles published by Indonesian Journal of Chemical Science and Technology will have unique DOI number. About Indonesian Journal of Chemical Science and Technology Country of Publication: Indonesia Publisher: Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Negeri Medan. Format: Print & Online ISSN: p-ISSN: 2622-1349, e-ISSN: 2622-4968 Frequency: Biannual Publication Dates: January and July Article Processing Charges: Yes Types of Journal: Academic/Scholarly Journals Open Access: Yes Indexed & Abstracted: Yes Policy: Peer-reviewed Review Time: Eight Weeks Approximately IJCST is Indexes/Abstracted in: Google Scholar Garda Rujukan Digital (GARUDA) PKP Index International Standard Serial Number (ROAD) Neliti BASE
Antioxidant activity of local Gompang Batu Plants (Lobelia nummularia Lam) in vitro DPPH Method
Free radicals are reactive atoms or molecules because they contain unpaired electrons that easily attack body structures, causing various diseases such as cancer, liver, heart and other degenerative diseases. Antioxidants are compounds or molecules that can reduce free radicals. Natural antioxidants are needed to reduce the effects of using synthetic antioxidants. The local plant gompang batu (Lobelia nummularia Lam) is found in Ruhut Bosi Village, Pangaribuan District and has been used by the community as a traditional medicine. This study aims to determine the content of secondary metabolites and antioxidant activity of ethanol extract of gompang batu in vitro using the DPPH (2,2 diphenyl-1-picrylhydrazyl) method. The results of the phytochemical screening test of the gompang batu plant contain secondary metabolites of flavonoids, alkaloids, steroids/terpenoids and saponins. The results of the antioxidant activity test of the ethanol extract of gompang batu obtained an IC50 value of 135,095 ppm (moderate category) and an IC50 value of vitamin C (as a positive control) of 39,390 ppm.
Antibacterial Potential of Gompang Batu Plant Extract (Lobelia nummularia Lam) Against Skin Disorder-Causing Bacteria
Skin disorders are common health problems that are often caused by bacterial infections such as Staphylococcus epidermis and Propionibacterium acnes. This study aims to analyze the antibacterial potential of n-hexane, ethyl acetate, and ethanol extracts of gompang batu (Lobelia nummularia Lam) plants against bacteria that cause skin disorders. Extraction was carried out by maceration with solvents of varying polarity. Antibacterial tests were carried out using the disc diffusion and microdilution methods with six treatments (chloramphenicol, DMSO, 1.25%; 2.5%; 5% and 10% extract). The results showed that the ethanol extract with a concentration of 10% had the most effective antibacterial activity with an inhibition zone of 14.0 mm (P. acnes bacteria) and 13.8 mm (S. epidermis bacteria). The MIC value of the extract ranged from 156.25 to 625 µg/mL and the MBC value of all extracts> 2500 µg/mL indicated bactericidal properties. Gompang batu has the potential as a natural antibacterial for skin infections. N-hexane extract contains steroids and tannins; ethyl acetate contains alkaloids, flavonoids, steroids and tannins; ethanol contains alkaloids, flavonoids, terpenoids and tannins.
Toxicity of Gompang Batu Plant Extract (Lobelia nummularia Lam) with BSLT (Brine Shrimp Lethality Test) Method as Raw Material for Medicine
Gompang Batu is a traditional medicinal plant found in Pangaribuan, North Tapanuli, Sumatra, Indonesia. Identification confirmed that gompang batu is Lobelia nummularia Lam from the Campanulaceae family. This study aims to determine the toxicity and phytochemical content of three types of gompang batu extracts. The Brine Shrimp Lethality Test (BSLT) method.was used for toxicity testing. Extraction was conducted through maceration using n-hexane, ethyl acetate, and ethanol solvents. LC50 values were 18.05 µg/mL for ethanol extract (very toxic), 27.59 µg/mL for ethyl acetate extract (very toxic), and 51.34 µg/mL for n-hexane extract (toxic). Phytochemical analysis showed that the ethanol extract contains abundant alkaloids, flavonoids, saponins, terpenoids and tannins. Ethyl acetate extract contains alkaloids, steroids, flavonoids, saponins, and tannins moderate tannins. N-hexane extract contains steroids and a small amount tannins. L. nummularia extract is classified as toxic and show potential as a medicinal raw material.
Thermodynamic and Kinetic Study on the Reaction Mechanism of Paracetamol Formation from 4-Aminophenol Using Computational Chemistry Methods
Paracetamol, also known as acetaminophen, is one of the most widely used drugs worldwide and is included in the WHO Essential Medicines List. The synthesis process of paracetamol is carried out through the acetylation reaction of 4-aminophenol with acetic anhydride, producing paracetamol and acetic acid as a by-product. This study aims to analyze the thermodynamic and kinetic aspects of the paracetamol formation reaction from 4-aminophenol using a computational chemistry approach. Calculations were performed using the Restricted Hartree-Fock (RHF) method with a 3-21G basis set implemented in the NWChem software, while molecular structure visualization was conducted using Jmol and Avogadro. The results show that the energy change (ΔE) is –25.0107 kJ/mol (exothermic). In addition, the activation energy (Ea) required to reach the transition state is recorded at 623.13 kJ/mol.
Thermodynamic and Kinetic Study of the Reaction Mechanism of Acetylsalicylic Acid Formation Using Computational Chemistry Methods
Acetylsalicylic acid or aspirin is one of the most widely used non-steroidal anti-inflammatory drugs (NSAIDs) in medicine because of its properties as an analgesic, antipyretic, and antiplatelet. This study aims to examine the thermodynamic and kinetic aspects of the reaction mechanism of aspirin formation from salicylic acid and acetic anhydride using a computational chemistry approach. The method used to determine energy is the computational chemistry method, the theory used is metode Restricted Hartree-Fock (RHF) with a basis set of 3-21G. The calculation results show the formation of energy (ΔE) of the reaction of -1.21 kJ/mol. The magnitude of the activation energy (Ea) from the computational chemistry calculation is 7.95 kJ/mol. The structure of the intermediate was also successfully identified and visualized, supporting a two-stage reaction mechanism with the presence of a transition state
Effectiveness of Metanil Yellow Adsorption Using CTAB-Modified Activated Carbon from Areca Nut Husk (Areca catechu L.)
This study investigates the adsorption efficiency of Metanil Yellow using activated carbon derived from areca nut husk (Areca catechu L.), which was chemically activated with KOH and modified with CTAB surfactant. The adsorbent was characterized using FTIR and UV-Vis spectroscopy to identify functional groups and determine optimum adsorption parameters. FTIR analysis confirmed the presence of functional groups such as –CH₂, –C–N, and –N⁺(CH₃)₃, indicating successful surface modification. UV-Vis analysis showed that the maximum adsorption occurred at a wavelength of 494 nm. The optimum conditions were achieved at an adsorbent mass of 1.5 g, dye concentration of 15 ppm, and contact time of 60 minutes, with adsorption efficiency reaching over 97%. These findings suggest that CTAB-modified areca nut husk activated carbon has strong potential as an effective and low-cost adsorbent for removing dyes from wastewater.
Adsorption of Metanil Yellow Dye with Sugarcane Bagasse (Saccharum offinarum L.) Activated Carbon Modified with Cetyl Trimethyl Ammonium Bromide (CTAB) Surfactant
Environmental pollution caused by textile industry wastewater containing synthetic dyes such as Metanil Yellow has become a serious concern due to its carcinogenic nature. This study aims to determine the adsorption capacity of activated carbon derived from sugarcane bagasse waste (Saccharum officinarum L.), which was activated using Potassium Hydroxide (KOH) and modified with the cationic surfactant Cetyl Trimethyl Ammonium Bromide (CTAB). The activated carbon was produced through carbonization at 500 °C for 2 minutes, followed by chemical activation using 5N KOH and surface modification with CTAB. FTIR characterization showed spectral changes with the appearance of new functional groups such as –CH₂ vibrations (2961 and 2849 cm⁻¹), –C–N (1020 cm⁻¹), and quaternary ammonium –N⁺(CH₃)₃ (1470 cm⁻¹), indicating successful interaction of CTAB molecules on the carbon surface. The adsorption results showed that optimum conditions were achieved at an adsorbent mass of 1.5 grams, Metanil Yellow concentration of 25 ppm, and a contact time of 30 minutes, with an adsorption efficiency of 94%.
Synthesis and Characterization of Banana Frond-Nanocytosan Bioadsorbent
FTIR characterization of the activated carbon showed the presence of functional groups including –OH (3207 cm⁻¹), aliphatic C–H (2886–2837 cm⁻¹), C≡C or CO₂ (2352–2120 cm⁻¹), aromatic C=C (1592 cm⁻¹), C–O (1086 cm⁻¹), and metal–O (533 and 465 cm⁻¹). The FTIR spectrum of chitosan indicated the presence of –OH and –NH groups (3641 cm⁻¹), –COO⁻ (1411 cm⁻¹), and glucose ring structures (870 and 711 cm the optimum result was achieved with 1% nanochitosan-coated adsorbent at a mass of 2,5 g and a contact time of 30 minutes, resulting in an FFA reduction of 2.51%. The nanochitosan-coated activated carbon showed the highest adsorption efficiency at 73.74%.
Effect of Fermentation Time on Acidity, Electrical Voltage and Volume of Apple (Malus domestica), Mango (Mangifera indica), Starfruit (Averrhoa bilimbi) Solutions
This study aims to analyze the effect of fermentation time on the electrical voltage, acidity (pH), and solution volume of apple, mango, and starfruit extracts as natural electrolytes in electrochemical cells. The fruit extracts were fermented using baker's yeast (Saccharomyces cerevisiae) for five days at room temperature, with measurements of electrical voltage, pH, and volume on days 1, 3, and 5. The results showed an increase in electrical voltage over fermentation time, with the highest value in starfruit (0.9 Volt, pH 2, final volume 140 mL). The decrease in pH and solution volume during fermentation indicated an increase in acidity and ion concentration which strengthened the conductivity of the solution as an electrolyte. This study proves the potential of local fruit extracts as a source of environmentally friendly electrolytes for alternative energy based on bioelectrochemistry.
The Effect of Acids, Bases and Salts in Removing Rust Using the Electrolysis Method
Corrosion is a natural process of metal deterioration caused by chemical or electrochemical reactions with the surrounding environment, and it commonly occurs in iron and steel. This study examined the use of electrolysis as a simple method to reduce rust on iron surfaces by applying several electrolyte solutions. The solutions tested included sodium chloride, citric acid, acetic acid, sodium bicarbonate, and water, each at a concentration of 10%, while citric acid was also varied up to 100%. Electrolysis was performed for 10 to 30 minutes on both positive and negative poles. The findings showed that sodium chloride solution gave the highest effectiveness in rust removal, with 0.93% rust loss on the negative pole and 0.58% on the positive pole. Increasing solution concentration and treatment time further improved the rust removal rate, reaching 2.50% at 30 minutes.
Electrical Properties of Tropical Fruit Extracts: Effects of EM4 Fermentation and Thermal Processing
This study examines the electrical properties of fermented pineapple and lime extracts subjected to Effective Microorganism 4 (EM4) fermentation and thermal treatment at varying temperatures. The fermentation process was conducted over a period of six days, with temperature conditions set at 30°C and 70°C. The results indicate that the lime extract generated higher voltage and current outputs compared to the pineapple extract, particularly on the sixth day of fermentation. Furthermore, the thermal treatment revealed a more pronounced electrical response in lime extract, as evidenced by a greater increase in current at elevated temperatures. These findings suggest that lime extract, when combined with EM4 fermentation and optimal thermal conditions, exhibits greater potential for application in alternative bioelectric energy generation.
Computational Study of Fe(II) Complex Compound Structure Prediction with Thiocyanate (SCN-) and Pyridin (C5H5N) Ligands Using the RHF (Restricted Hartree Fock)
The formation of Fe(II) complex compounds with thiocyanate (SCN-) as well as pyridin (C5H5N) forms a tetrapyridinditiocyanateobesi(II) complex compound, [Fe(SCN)2(py)4]. The comparison of these complex compounds is still engineering, so the researchers examined the comparison of the structure of stable complex compounds on Fe(II) with thiocyanate and pyridin ligands, by continuing previous research using computational chemistry. Complex compounds that are more stable and the most suitable molecular formula based on computational calculations using RHF hybrid functions and 6- 31G basis sets, geometry optimization of molecules from NWChem version 6.6 and Jmol software version 14.28.29. The energy of the computational calculation using RHF/6-31G for the structure Fe(SCN)2(C₅H₅N)4: -1524.86976182444 KJ/mol; Fe(SCN)3(C₅H₅N)3 structure: -1557.98302881166 KJ/mol; and Fe(SCN)4(C₅H₅N)2 structure: -2083.53616162888 KJ/mol. The change in formation energy indicates that the structure of Fe(SCN)4(C₅H₅N)2 is the most stable. The most suitable molecular formula for the Fe(II) complex compound is [Fe(SCN)4(C₅H₅N)2].
Synthesis of Cinnamic Acid from Benzoin Extract Using Sulfuric Acid as a Catalyst
This study explores the synthesis of cinnamic acid from benzoin extract using sulfuric acid as a catalyst. Benzoin resin was extracted to obtain cinnamyl cinnamate, which was then hydrolyzed under acidic conditions to yield cinnamic acid. The synthesized compound was characterized using Fourier- transform infrared (FTIR) spectroscopy and gas chromatography-mass spectrometry (GC-MS). The FTIR spectra confirmed the presence of characteristic functional groups of cinnamic acid, while GC- MS analysis verified its purity and molecular structure. The optimized reaction conditions provided a significant yield, indicating the efficiency of this method in producing cinnamic acid from a natural source.
Kinetics and Equilibrium Properties of Cu(II) Adsorption Using Modified Activated Carbon from Empty Oil Palm Fruit Bunches
Oil palm empty fruit bunch (EFB) is a biomass waste containing lignocellulose that has the potential to be used as activated carbon to adsorb heavy metals such as Cu(II). This study aims to compare the adsorption performance of Cu(II) ions from three types of TKKS-based adsorbents, namely pure activated carbon (A.C), Fe-Cu metal modified activated carbon (A.C-Fe-Cu), and activated carbon composite with Cu(TAC)₂ (A.C-Cu(TAC)₂). Data were obtained from two previous studies and analyzed using first- and second-order pseudo-kinetic models, as well as Langmuir and Freundlich isotherm models. Results showed that all adsorbents followed a two-order pseudo-kinetic model with R² ≥ 0.998, indicating a chemisorption mechanism. A.C-Fe-Cu showed the highest maximum adsorption capacity (389.47 mg/g) and the best fit to both isotherm models, while A.C-Cu(TAC)₂ showed suboptimal results. Thus, the modification of TKKS with Fe-Cu metal synergistically increases the effectiveness of adsorption on Cu(II) ions and has potential for wastewater treatment applications.
Adsorption of Soluble Ammonia Using A Porous Polymer Composite Cu-(TAC) And Activated Carbon Empty Fruit Palm Oil
This study aims to determine the stages in the process of making activated carbon, synthesis of porous polymer composites Cu(TAC) and activated carbon composites (KA-Cu(TAC) for adsorption of dissolved ammonia (NH4OH). To know the characterization results of activated carbon and KA- Cu(TAC), as well as knowing the optimum mass, concentration, and contact time of activated carbon KA-Cu(TAC) for the adsorption of dissolved ammonia. The research stages started from Empty Oil Palm Bunches (EFB) used as biosorbents for carbon production at 500oC. The resulting product was activated with H3PO4, then modified with porous polymer Cu(TAC) to make a composite. The KA-Cu(TAC) composite was synthesized by reflux method. Then MOFs, activated carbon and KA-Cu(TAC) composite were characterized by BET. The BET characterization results showed that the successfully synthesized KA-Cu(TAC) composite experienced an increase in surface area.In the NH4OH adsorption process the optimum mass efficiency on activated carbon still increased at 8 grams while the KA-Cu(TAC) composite obtained an efficiency of 36, 6% and optimally at a mass of 4 g. At variations in concentration, the efficiency of the two samples still decreased. And the optimum time efficiency obtained in the NH4OH adsorption process with activated carbon was 70% and the KA-Cu(TAC) composite was 86.6%, both samples were equally optimal at 75 minutes
Influence of Citric, Acetic, and Ascorbic Acids on the Solubility of Paracetamol
This study examined the influence of citric, acetic, and ascorbic acids on the solubility of paracetamol, an analgesic with inherently low aqueous solubility. Paracetamol tablets were dissolved in different concentrations of organic acid solutions, and dissolution times were visually monitored. The most rapid dissolution occurred in 30% acetic acid solution (190 seconds), followed by the citric–acetic acid mixture. Increasing paracetamol mass extended dissolution time, with saturation reached at 3.5 g. Enhanced solubility was attributed to hydrogen bonding interactions between organic acids and paracetamol molecules. Compared with complex techniques such as solid dispersions or co-amorphous systems, this acid-assisted approach is simple, low-cost, and requires no specialized equipment. These findings highlight the role of weak organic acids as practical solubility enhancers and suggest a promising strategy to improve paracetamol bioavailability and therapeutic effectiveness.
Exploring the Redox Reaction Potential of Local Fruits: Galvani Cell Trials Based on Areca nut (Areca catechu), Rimbang (Solanum torvum), and Bangkok starfruit (Averrhoa carambola)
This research aims to explore the potential of three fruits, such as areca nut (Areca catechu), rimbang (Solanum torvum), and star fruit (Averrhoa carambola), as a natural electrolyte source in generating electricity through a simple Galvani cell test. The research method includes making Galvani cells using fruit pieces as electrolyte media, measuring the voltage and current produced, and testing the ability to light an LED as an indicator of electrical output. The measurement results showed that areca nuts produced the highest voltage and current compared to rimbang and star fruit, demonstrating its effectiveness as a natural electrolyte. This finding indicates that local fruits have the potential to be an environmentally friendly electrochemical energy source material that can be applied in education and simple technology. This research opens opportunities for further development in utilizing local biological resources for electrochemical applications.
Sustainable Candle Production from Waste Cooking Oil and Waste Lubricating Oil
This study investigates the potential utilization of waste cooking oil and used lubricant oil as raw materials for candle production. These waste materials, often regarded as environmental pollutants, contain fats and hydrocarbons that can be converted into value-added products. The manufacturing process involved filtration, heating, and the incorporation of additives such as paraffin wax to enhance quality and stability, followed by molding. The resulting candles demonstrated acceptable physical properties, including melting points and burning times comparable to standard requirements. However, noticeable differences in color and odor were observed when compared to commercial candles. Despite these limitations, the valorization of waste cooking oil and used lubricant oil presents an environmentally friendly and cost-effective alternative, contributing to the development of sustainable products. Further research is recommended to optimize the blending ratios and additive compositions in order to improve the overall performance of the candles
Effect of Sugar, Salt, and Flavorings Addition on Temperature Changes and Specific Heat Capacity in Citric Acid, Acetic Acid, and Ascorbic Acid Solutions
This study aims to evaluate the effect of the addition of additives in the form of sugar, salt, and flavorings on changes in temperature and type heat capacity in citric acid, acetic acid, and ascorbic acid solutions. The methodology used is a quantitative experimental approach with direct observation of temperature changes as well as calculation of enthalpy changes (ΔH) in various combinations of acidic and additive solutions. The results of the analysis showed that the types of additives exerted different effects on the thermal stability and heat capacity of each acidic solution. Sugars tend to provide the most optimal thermal stability with minimal fluctuations in ΔH change, while salts cause the greatest fluctuations. Flavorings show a more varied and inconsistent pattern of change. These findings provide in-depth insights into the thermal characteristics of organic acid solutions with additive modification, contributing to the development of applications in the fields of food, pharmaceutical, and applied chemistry education.
Influence of Cooking Temperature on the Moisture Content and Organoleptic Properties of Pineapple, Banana, and Dragon Fruit Jam
Jam is a processed fruit product with high density and acidity, making it more stable than other fruit-based products. The jam-making process includes crushing the fruit, adding sugar, acid, thickening agents, and applying heat. Cooking temperature plays a critical role in determining the moisture content, texture, aroma, and taste of jam. This study investigates the influence of cooking temperature on the moisture content and organoleptic properties of pineapple (Ananas comosus), banana (Musa paradisiaca), and dragon fruit (Hylocereus spp.) jams. The jams were prepared by heating at various temperatures (900C, 1000C, 1100C), followed by moisture content measurement and organoleptic testing. Results showed that higher temperatures significantly reduced moisture content and enhanced sensory quality. Jams cooked at 110°C had the lowest moisture levels and the best organoleptic scores. These findings highlight the importance of temperature control in producing high-quality jam.
Influence of Temperature and Stirring Duration on the Solubility Kinetics of Palm Sugar (Arenga Pinnata) in Water: Implications for Food Processing Efficiency
Palm sugar (Arenga pinnata) is widely used in traditional and industrial food processing, where its solubility plays a crucial role in determining product consistency and efficiency. However, most previous studies have focused on the solubility of refined cane sugar, leaving limited understanding of how temperature and stirring conditions affect the dissolution behavior of palm sugar, which has a more complex composition. This study aims to examine the effect of temperature, solute mass, and stirring duration on the solubility of palm sugar in water. A laboratory-based experimental method was employed, varying temperature (50°C, 75°C, 100°C), sugar mass (20 g and 40 g), and stirring duration (1 and 2 minutes). In general, the findings indicate that higher temperature accelerates the dissolution rate, while greater solute mass extends dissolution time. These results confirm temperature as the dominant factor influencing dissolution kinetics. The implications of this study include improving household practices for faster sugar preparation, optimizing processing efficiency in small-scale food industries, and contributing to food science education by providing an applied example of solubility principles.
Natural Dye Production from Beetroot Using Vinegar and Non-Solvent : pH and Colorfastness Testing on White Fabric
Natural dyes derived from plants are increasingly attractive due to their safety and environmental friendliness. This study aimed to investigate the effect of vinegar as a natural solvent on the colorfastness of beetroot (Beta vulgaris L.) dye applied to white fabric. The research involved extracting pigments from beetroot, applying them to fabric, and testing the solution’s pH, drying time, and wash fastness. The results showed that pure beetroot extract had a pH of 5.2, while the addition of vinegar reduced the pH to 2.5–3.1. Fabric dyed with beetroot + vinegar exhibited higher initial color intensity (score 11) compared to pure beetroot (score 9), but its colorfastness dropped sharply after washing (score 4 vs. 7). Vinegar addition also prolonged fabric drying time from 12 minutes (without vinegar) to 17.5 minutes (with 20 mL vinegar). These findings indicate that vinegar enhances initial dye brightness but reduces colorfastness after washing. Nevertheless, beetroot dye remains a safer and eco-friendly alternative to synthetic dyes, although further optimization is required to improve its durability.
Production of Natural Dye from Butterfly Pea Flower (Clitoria Ternatea T.) Extract Using Citric Acid Solvent from Bilimbi (Averrhoa bilimbi)
Natural dyes extracted from butterfly pea flowers (Clitoria ternatea L.) hold significant potential as alternatives to synthetic dyes in the food and textile industries. This study aims to evaluate the effectiveness of citric acid isolated from bilimbi (Averrhoa bilimbi L.) as a solvent for extracting anthocyanin pigments from butterfly pea flowers. Ultrasonic extraction was conducted using different solvents (citric acid and ethanol) and varying extraction durations. The results showed that the extract yield ranged from 2.6% to 5.5%, with an average of 3.99%. Ethanol produced a higher yield than citric acid; however, citric acid significantly reduced the extract’s pH to a range of 1–6, potentially enhancing anthocyanin pigment stability. Additionally, extraction time positively influenced yield up to an optimal point, after which degradation of active compounds led to a decline. These findings suggest that bilimbi-derived citric acid has potential as an eco-friendly solvent for natural dye production, though further optimization is needed to enhance extraction efficiency and color stability.
Kinetics and Equilibrium Properties of Fe(II) Adsorption Using Modified Empty Palm Oil Bunches Activated Carbon
The increasing palm oil production in Indonesia contributes to higher agricultural waste, particularly Empty Fruit Bunches (EFB). This waste can be processed into activated carbon as an adsorbent to remove Fe(II) ions from Palm Oil Mill Effluent (POME). This study reviews two EFB-based adsorbents: Fe-Cu modified activated carbon and a composite of activated carbon with Copper-TAC Metal Organic Frameworks (Cu(TAC)₂). Adsorption kinetics data show that the pseudo-second-order model fits best, with the highest regression coefficient (R² = 0.99637) found in the Cu(TAC)₂ composite, indicating a chemisorption mechanism. Adsorption equilibrium analysis using Freundlich isotherm revealed that while all materials fit the model, plain activated carbon had an unfavorable 1/n value (>1), suggesting weak interaction between adsorbent and adsorbate. Based on kinetic and isotherm analysis, the Cu(TAC)₂ composite was more effective for Fe(II) adsorption than Fe-Cu or unmodified activated carbon.
Effectiveness of Modified Empty Palm Oil Bunch-Based Activated Carbon for Reducing Ammonia Content in Palm Oil Wastewater
Indonesia, particularly North Sumatra, is a major producer of palm oil, generating significant waste such as empty fruit bunches (EFB) and ammonia-rich wastewater. Ammonia pollution poses serious environmental risks if not treated properly. This study explores the potential of three types of adsorbents—Fe-Cu modified activated carbon, AC-Cu(TAC)₂ composite, and unmodified activated carbon—for ammonia adsorption. Activated carbon was synthesized from EFB and further modified using Fe-Cu and Cu(TAC)₂. Adsorption experiments were conducted with variations in adsorbent mass, contact time, and NH₄OH concentration. The results showed that Fe-Cu modified activated carbon had the highest ammonia removal efficiency (90%), while the AC-Cu(TAC)₂ composite had the highest adsorption capacity. Equilibrium analysis revealed that the AC-Cu(TAC)₂ composite fit both Langmuir and Freundlich isotherm models (R² = 1), suggesting both monolayer and heterogeneous adsorption. The unmodified activated carbon followed the Langmuir model (R² = 0.9498), while Fe-Cu modified activated carbon did not fit either model. Kinetic studies indicated that Fe-Cu modified activated carbon followed a pseudo-first-order model (R² = 0.9936), implying physisorption, whereas both AC-Cu(TAC)₂ and unmodified activated carbon followed pseudo-second-order models (R² = 0.9779 and 0.9869), indicating chemisorption. These findings highlight the promising potential of modified EFB-based adsorbents for ammonia removal in wastewater treatment applications.
Kinetics Study Addition Reaction for Methyleugenol with Formic Acid to Produce The Methyleugenol Formic Ester as Intermediate Compound of Hypertension Drug
The methyl eugenol formic ester is the intermediate formation of the 1-(3,4-dimethoxy phenyl)-2-amino-2-cyano propane compound, a hypertension drug. This study aimed to find the value of the reaction order and study the mechanism of an addition reaction of methyl eugenol with formic acid to produce the methyl eugenol formic ester. Gas chromatography analysis of the residual methyl eugenol determines the reaction order. There are two dominant products in the synthesis of methyl eugenol formic ester, resulting in the formation reaction of methyl eugenol formic predictable in a two-way reaction mechanism. The determination of the energy of the reactants, products, and transition compounds in the formation reaction of methyl eugenol formic ester compound prescribed through computational studies using NWChem 6.0 and visualization using Jmol. The results of the analysis of the data obtained several conclusions: The value of the reaction ordered for methyl eugenol with formic acid is the first order. Based on the computational result shows that the enthalpy change for the reaction product is ΔH(1) = -47,810 KJ/mol and ΔH(2) = -60,545 KJ/mol. The activation energy for both transition compounds is Ea(1) = 163,1937 KJ/mol and Ea(2) = 370,3477 KJ/mol. This fact indicates that the formation of methyl eugenol formic ester compound using the method (1) was more likely than (2). The prediction is based on the determination of Ea with the computational chemistry following the experimental result, which shows the product of (1) more than the product of (2).
Temperature Influence on Chemical Reaction Rates and Gas Formation
Reaction rate is fundamentally defined as the change in the concentration of reactants or products per unit time, and is known to be influenced by several determinants, including surface area, temperature, catalysts, and reactant molarity or concentration. The present study specifically investigates the validity of the widely accepted principle that temperature plays a significant role in modulating reaction rates. Experimental variations were introduced, both in terms of temperature levels and the types of chemical mixtures employed. The findings confirm that temperature indeed accelerates gas generation across all tested reaction systems. However, in mixtures exhibiting higher viscosity, gas formation proceeds more slowly due to reduced molecular mobility. Consequently, in the softener–baking soda system, the onset and progression of gas evolution show noticeable differences compared to less viscous mixtures.
Creative Ice Cream Experiment Using the Freezing Point Depression Principle
This research aims to explore creative approaches in ice cream production by utilizing the effect of freezing point depression. Through these experiments, we employed various additives that influence the physical properties of ice cream, resulting in a final product that is softer, creamier, and able to maintain optimal texture at different temperatures. The experimental method involved varying the types of additives combined with the base ice cream mixture. The measured parameters included freezing point depression, texture, and softness of the produced ice cream. The collected data were analyzed to determine how each additive affected the physicochemical characteristics of the product. The results showed that differences in sugar content among the ingredients significantly influenced the degree of freezing point depression in the ice cream.
Growth Response of Mung Bean Plants Vigna radiata L. and Spinach Amaranthus hybridus L. Under Acidic and Alkaline Conditions
This study investigates the growth response of mung bean Vigna radiata L. and spinach Amaranthus hybridus L. under controlled acidic neutral and alkaline environments across a wide pH gradient from pH 3 to pH 14. The work provides a comparative assessment of two species with distinct physiological characteristics to clarify how hydrogen ion concentration shapes vegetative development. The novelty of this study lies in its direct evaluation of extreme pH conditions using a uniform experimental design that allows both species to be examined under identical chemical exposure, enabling a clear contrast of tolerance thresholds. Plant height was recorded daily for 13 days to capture early stage vegetative dynamics. Both species exhibited their highest stability near pH 7 while severe deviations from neutrality reduced growth through nutrient imbalance and physiological stress. Mung bean showed moderate tolerance at pH 9.5 whereas spinach displayed enhanced performance within mild alkalinity. Strong acidity and strong alkalinity produced structural damage in both species. The findings highlight the critical role of soil pH in plant performance and provide foundational insight into species specific tolerance ranges that can support more informed management of crops grown in chemically variable environments.
Effect of Electrode Type and Current Strength on the Mass of Substance Reduced at the Cathode in the Electrolysis Process
This study investigates the effect of electrode type and current strength on the mass of hydrogen gas produced at the cathode during the electrolysis of sodium chloride solution. A simulation based on Faraday’s law was conducted using three electrode materials—carbon, copper, and zinc—under controlled current settings of 0.10 A, 0.20 A, and 0.30 A for a fixed electrolysis duration of 30 minutes. Current efficiency values were assigned to each electrode to model realistic performance differences, with copper exhibiting the highest efficiency, followed by zinc and carbon. The results show that increasing the current leads to a linear rise in the mass of hydrogen produced for all electrode types, confirming the proportional relationship between electric charge and cathodic reduction predicted by Faraday’s law. Additionally, copper electrodes produced the highest hydrogen yield at all current levels, while carbon generated the lowest, indicating that electrode characteristics influence electrochemical efficiency. Overall, the findings demonstrate that current strength is the dominant factor determining the mass of reduced species at the cathode, whereas electrode material provides a secondary yet significant contribution to electrolysis effectiveness.
Effect of Sugar Addition on the Electric Current Strength of Mixtures with Vinegar, Lime Extract, Coffee, Salt Solution, and 70% Alcohol
This study aims to examine the electric current strength of sugar mixed with various electrolyte and non-electrolyte solutions. The research employed an experimental approach using vinegar, lime extract, coffee solution, salt solution, and 70% alcohol combined with sugar solutions. A battery system and a digital multimeter were utilized to measure the resulting current in each mixture. The findings indicate that increasing the amount of sugar leads to a reduction in current strength, whereas decreasing the sugar content results in a higher current output.
Influence of EM4 Inoculum on Biogas Yield and pH Dynamics in Lettuce and Cabbage Waste Fermentation
Biogas production from vegetable waste offers a practical pathway for reducing organic residues and supporting small-scale renewable energy systems. This study investigates the influence of EM4 inoculum on gas accumulation and pH dynamics during an 8-day batch fermentation of lettuce and cabbage waste. Four reactors were prepared containing 200 g vegetable waste and 200 mL water with or without 30 g EM4. Gas accumulation was quantified by balloon circumference at day 2, day 4, day 6 and day 8 and converted to volume using geometric calculations. Lettuce generated the highest peak volumes with maximum values exceeding 330 cm³ while cabbage produced less than 60 cm³ under comparable conditions. pH trajectories showed that cabbage plus water decreased from pH 7 to pH 6 whereas lettuce plus water increased from pH 7 to pH 8. Reactors containing EM4 stabilised at pH 6 throughout the fermentation indicating inoculum-supported buffering. These results demonstrate that substrate characteristics strongly influence early-stage gas formation and that EM4 moderates pH fluctuations even under uncontrolled ambient conditions. The findings provide initial evidence that lettuce is a more degradable feedstock than cabbage and emphasise pH regulation as a key requirement for improving methane-oriented biogas performance in simple batch systems.
Effect of Organic and Inorganic Compounds on the Conductivity of Salt Solutions
This study examines the effects of selected organic and inorganic compounds on the electrical conductivity of salt solutions. Organic substances (sugar, coffee, tea, and a surfactant-based cleaner) and inorganic additives (ammonium chloride in cough medicine, povidone–iodine, and carbonated beverage) were mixed with salt solutions at varying concentrations to evaluate their influence on ion availability and mobility. The results show that conductivity increases proportionally with salt concentration, confirming that ion content is the primary factor governing charge transport. Inorganic ionic additives significantly enhanced conductivity by releasing additional ions into the solution, whereas non-ionic organic compounds consistently reduced conductivity at low salt levels by diluting ionic species and hindering ion mobility. Conductivity in organic mixtures increased only when salt concentration became dominant. These findings highlight the contrasting mechanisms of organic and inorganic additives in modifying electrolyte behavior and provide useful insight for chemistry education and simple electrochemical analysis.
Analysis of the Effect of Varying Concentrations of Strong Acids (HCl) and Weak Acids (CH3COOH) with Mixing of Bases (Detergent) on the Temperature Increase of the Reaction Results
Neutralization reactions between acids and bases are generally exothermic processes that release heat because of water formation from H⁺ and OH⁻ ions. This study aims to investigate the effect of varying concentrations of a strong acid (HCl) and a weak acid (CH₃COOH) on the temperature increase produced when these acids are reacted with a detergent-based alkaline material. Experiments were conducted using three acid concentrations—0.1 M, 0.3 M, and 0.5 M—each mixed with 3 g, 5 g, and 7 g of detergent in a reaction volume of 25 mL. The results indicate that increasing acid concentration correlates positively with greater temperature elevation. The largest temperature increase, 5.7°C, was observed in the reaction between 0.5 M HCl and 7 g of detergent, whereas the lowest increase, 0.5°C, occurred in the reaction between 0.1 M CH₃COOH and 3 g of detergent. Differences in ionization strength between strong and weak acids significantly influence the amount of heat released during neutralization. These findings demonstrate that both acid strength and base mass play important roles in determining the exothermic energy output of acid–base reactions.