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
Chemical Composition and Quality Parameters of Citronella (Cymbopogon nardus) Essential Oil Based on GC–MS and Physicochemical Analysis
Citronella (Cymbopogon nardus (L.) Rendle) essential oil is widely utilized in the perfume, cosmetic, and pharmaceutical industries, primarily due to its high content of citronellal, geraniol, and citronellol. This study aimed to evaluate the chemical composition and quality parameters of citronella essential oil using gas chromatography–mass spectrometry (GC–MS) and physicochemical analysis. The oil sample was obtained by steam distillation of fresh leaves and subsequently characterized in terms of specific gravity, refractive index, optical rotation, and flash point, while the chemical composition was determined based on GC–MS chromatogram peak areas. The physicochemical analysis showed a specific gravity of 0.894, refractive index of 1.477, optical rotation of −6.59°, and a flash point above 80 °C, indicating compliance with quality standards for citronella essential oil. GC–MS analysis identified 21 compounds, with trans-geraniol (70.65%), geranyl acetate (7.70%), β-citronellol (3.17%), and citronellal (1.78%) as the major constituents. These findings confirm that steam-distilled citronella essential oil exhibits good quality and a chemical profile that supports its potential for essential oil-based industrial applications.
Physical Properties of Polymer Composit Reinforced by Salak Bark Fiber (Salacca zalacca) and Nipah Bark Fiber (Nypa frutican)
Fiber composite is a material that has been widely used such as in vehicles, buildings and in industry. The use of natural fiber materials is prioritized because the costs incurred are relatively cheaper and also more environmentally friendly. This study aims to test the physical properties of composite reinforced by salak bark fibers and nipah bark fibers. The fibers are soaked using a solution of Sodium Hydroxide for 2 hours. The variation of the volume fraction used is 5% : 5% ; 5% : 10% ; 5% : 15 % ; 5% : 20%. The physical properties test carried out is a density and moisture content test. Based on the results of the study, the highest density value was 0.927 %. Meanwhile, the moisture content test value showed the highest moisture content value of 1.90%.
Characterization of the Physical and Biodegradation Properties of Biodegradable Plastic from Carboxymethyl Cellulose, Young Coconut Shells and Cassava Starch
Biodegradable plastics derived from renewable biomass were synthesized using carboxymethyl cellulose (CMC) isolated from young coconut husk and cassava starch at different CMC:starch ratios (1:1, 1:2, and 2:1). Physical characterization included tensile strength, elongation, Young’s modulus, and water resistance, while biodegradation performance was assessed through a 15-day soil burial test. The tensile strength reached its highest value at a ratio of 2:1 (2.0068 MPa), fulfilling the JIS 2-1707 requirement for biodegradable films. Elongation values were inversely related to CMC content, with the highest elongation (62.69%) observed at the 1:2 ratio. Water resistance was also optimal at the 1:2 ratio, indicating lower hydrophilicity compared to CMC-rich films. Biodegradation tests showed that bioplastics with higher CMC content (2:1) degraded fastest, achieving 97.37% mass loss on day 15. These findings demonstrate that the CMC:starch ratio significantly affects mechanical stability, moisture sensitivity, and biodegradation rate. Overall, the bioplastic films developed in this study exhibit promising properties for eco-friendly and lightweight packaging applications.
Optimization of Drying with a Food Dehydrator on the Quality of Tinuktuk Powder
Tinuktuk is a traditional Simalungun food product with immunomodulatory properties. To enhance convenience and extend shelf life, tinuktuk can be consumed as a powder produced by drying. In this study, drying optimisation was conducted using a food dehydrator at 40°C with drying times of 5, 6, 7, and 8 hours. Subsequently, tests were conducted to determine the quality of tinuktuk by analysing pH, water content, and ash content. The results showed that tinuktuk with optimal performance was obtained at 8 hours, as indicated by its pleasing texture and dryness. Specifically, the pH was 5.4, the water content was 8.20%, and the ash content was 6.31%.
Preparation of Banana Peel Activated Carbon Coated with Nanochitosan from Shrimp shells
Banana peel, an agricultural waste, contains valuable compounds suitable for use as an adsorbent to remove hazardous dyes and heavy metals from the environment. Activated carbon was prepared from banana peel using HCl as an activating agent. Chitosan was synthesized from shrimp shells through deproteinization, demineralization, and deacetylation, followed by characterization using FTIR. Nanochitosan was produced via ionic gelation and characterized using Particle Size Analyzer (PSA). The resulting nanochitosan was successfully coated onto activated carbon. FTIR analysis showed shifts in absorption intensity in both carbon and activated carbon, indicating successful activation and functional modification. The presence of chitosan was confirmed by the identification of N–H functional groups at 3248 cm⁻¹. PSA results showed that the synthesized nanochitosan had a particle size of approximately 86.14 nm. These findings demonstrate the successful synthesis of activated carbon coated with nanochitosan, with potential applications in environmental remediation through improved adsorption performance.
The Effect of Alkaline Base Activator Type on Biochar Character of Coconut Shell as a Heterogeneous Catalyst Support
Biochar derived from coconut shells shows promise as a support for heterogeneous catalysts. This study evaluated the effectiveness of alkaline activators (KOH 2 M, NaOH 2 M, and Ca(OH)₂ 2 M) in enhancing biochar properties. Biochar was produced by pyrolysis at 500 °C for 2 h, followed by chemical activation and calcination at the same temperature. The materials were characterized using FTIR, XRD, TGA, and Surface Area Analysis. Results indicate that alkaline activation modifies the biochar surface by increasing O–H, C=O, and C–O functional groups, improving polarity and adsorption capacity. The samples were predominantly amorphous and thermally stable, with minimal mass loss (0.149 mg). Among the activators tested, NaOH 2 M was the most effective, yielding a surface area of 306.233 m²/g, pore volume of 1.841 cc/g, and pore diameter of 1.202 nm. These properties suggest that NaOH-activated coconut shell biochar is a suitable carrier material for catalytic applications.
Synthesis of Zeolite from Fly Ash and Aluminum Can Waste as a Nickel (Ni) Adsorbent
Palm oil boiler fly ash and waste aluminum cans are abundant industrial residues that remain underutilized. This study aims to synthesize Y-type zeolite from boiler fly ash and aluminum can waste for application as an adsorbent to reduce nickel (Ni²⁺) content in industrial wastewater. The experiment employed variations in aluminum can mass (1 g, 2 g, 3 g) and boiler fly ash mass (60 g, 80 g, 100 g). Zeolite synthesis and its adsorption performance were evaluated in two stages. The obtained zeolite was characterized using FTIR and XRD to confirm Y-type zeolite formation, while AAS analysis determined nickel concentration. The optimal adsorption efficiency of 87.69% was achieved with 2 g aluminum can waste and 80 g boiler fly ash. These findings demonstrate that combining fly ash and aluminum waste can effectively produce zeolite Y with high potential as a sustainable adsorbent for heavy metal removal from wastewater.
Synthesis and Characterization of Liquid Natural Rubber (LNR) from SIR-10 as a Basic Material for Making Rubber Compounds
Liquid Natural Rubber (LNR) is synthesized from Standard Indonesian Rubber (SIR-10) through the process of deproteinization and oxidative degradation using phenylhydrazine/O₂. Deproteinization was carried out by the Soxhlet extraction method using acetone solvents to reduce protein content that can inhibit the degradation process. Furthermore, the rubber was oxidatively degraded and characterized using Fourier Transform Infrared (FTIR) and intrinsic viscosity measurements with an Ostwald viscometer. The FTIR results showed the emergence of new absorption bands at 3273 cm⁻¹ (O–H) and 1713 cm⁻¹ (C=O) indicating the formation of oxidized functional groups. Viscosity analysis showed a significant decrease in molecular weight from 3.717 × 10⁵ g/mol (SIR-10) to 2.375 × 10³ g/mol (LNR). These results confirmed that SIR-10 was successfully converted into LNR which has the potential to be used as a base material in the manufacture of rubber compounds.
Preparation and Characterization of Adsorbents from Tea Drains Coated With Nanochitosan From Green Mussels Shells
Tea dregs are abundant organic waste containing high cellulose content, making them a potential raw material for activated carbon production. Chemical activation using NaOH was selected to enhance adsorption capacity. Chitosan was obtained from green mussel shells through demineralization, deproteinization, and deacetylation processes. This study aimed to synthesize an adsorbent based on tea dregs activated carbon coated with nanochitosan derived from green mussel shells. Characterization was conducted using Fourier Transform Infrared Spectroscopy (FTIR) to identify functional groups and Particle Size Analyzer (PSA) to determine chitosan particle size. FTIR analysis indicated decreased absorption intensity of –OH, C=O, C–O, and C–H groups after activation, suggesting removal of organic components and increased carbon purity. The isolated chitosan exhibited NH₂ groups at 1653 cm⁻¹, while PSA results showed an average particle size of 62.08 nm. The resulting composite adsorbent demonstrated promising characteristics for water treatment, particularly in heavy metal adsorption applications.
Preparation and Characterization of Biochar from Coconut Shells with The Addition of Cu Metal as a Heterogeneous Catalyst
Biochar is a carbon-rich solid produced by pyrolyzing biomass in the absence of oxygen. This study prepared and characterized coconut shell biochar modified with copper (Cu) as a heterogeneous catalyst. Coconut shells were selected for their high carbon content and porous structure. Biochar was produced by pyrolysis at 500 °C for 2 h under nitrogen, activated with KOH (1:4 w/w), and calcined at 500 °C. Copper was introduced by impregnating the activated biochar with a Cu(NO₃)₂·6H₂O solution, stirring for 5 h, followed by calcination at 500 °C. Characterization using FTIR, XRD, SEM-EDX, and BET identified functional groups, crystal structure, morphology, elemental composition, and surface area. Results indicate that Cu addition enhances functional group intensity, sharpens XRD peaks, increases surface area, and promotes more uniform pore distribution. These changes suggest improved catalytic potential for biomass conversion, particularly in steam reforming applications.
The Effect of Acid Activator Type on Character Biochar from Coconut Shell as a Heterogeneous Catalyst Carrier
This study examines the effect of acid activators (H₃PO₄, H₂SO₄, and HCl) on the characteristics of coconut shell biochar as a heterogeneous catalyst carrier. Biochar was produced through pyrolysis at 500°C, 2M acid activation at 60°C, and calcination at 550°C, then characterized using TGA, FTIR, XRD, and BET. Acid activation increased the surface area from 4.025 m²/g to 369.335 m²/g (HCl), 359.557 m²/g (H₃PO₄), and 324.938 m²/g (H₂SO₄). FTIR showed modification of P-O, S=O, and hydroxyl-carbonyl functional groups. The crystal structure remained amorphous with HCl producing the highest intensity. HCl gave the best results with a surface area of ​​369.335 m²/g, a micropore area of ​​631.7 m²/g, and superior thermal stability (mass loss of 0.587 mg), indicating potential as a heterogeneous catalyst carrier.
Temperature Effect on Oil Solubilization Kinetics and Activation Energy of Moringa oleifera Biosurfactant Detergent
The environmental impact of synthetic surfactants in detergents has encouraged the development of eco-friendly alternatives from natural sources, such as Moringa oleifera leaves. This study aimed to determine the activation energy and evaluate the oil solubilization performance of a Moringa oleifera-based biosurfactant detergent compared with a synthetic detergent at various temperatures. The biosurfactant was prepared through maceration followed by acid activation using HCl. Product evaluation included organoleptic analysis, pH and density measurements, and kinetic analysis based on the Arrhenius equation. The results showed that the formulated biosurfactant met SNI quality standards, with pH values ranging from 8 to 10 and density between 1.176 and 1.199 g/mL. Arrhenius analysis revealed a lower activation energy for the Moringa oleifera detergent (4.16 kJ/mol) compared to the synthetic detergent (6.92 kJ/mol). These findings indicate enhanced oil solubilization efficiency and support its potential as a sustainable detergent alternative.
Kinetics of extraction of essential oils from ginger variations (Zingiber officinale Rosc.)
Ginger as one of the root plants can produce essential oils. Meanwhile, essential oils can be produced from plants. Essential oils are extracted from Emprit ginger, Red ginger and Gajah ginger using ethanol solvent to temperatures below 40°C. This research includes one-component equilibrium which includes the process of changing the molecules of substances which are influenced by changes in concentration, pressure or volume and most importantly changes in temperature. Emprit ginger tends to show order 1. Gajah ginger tends to follow order 1, while Red ginger tends to follow both orders so it is difficult to determine the right order, therefore requiring more time variations. Then the most essential oil lumps were obtained in Red ginger at 6.89 grams, Gajah ginger at 2.87 grams and Emprit ginger at 0.65 grams.
Experimental Observation of Phase Behavior and Turbidity in Oil–Water–Sodium Hypochlorite Ternary Systems
This study experimentally examines the phase behavior of ternary mixtures composed of oil, distilled water, and sodium hypochlorite (NaOCl) solution using a turbidity (cloud-point) observation method rather than numerical liquid–liquid equilibrium calculations. Three oils—coconut oil, olive oil, and baby oil—were tested to evaluate how their physicochemical properties influence visible phase behavior. Oil and NaOCl were first mixed at different ratios, followed by the gradual addition of distilled water until turbidity appeared, marking the boundary between temporary dispersion and phase separation. The required water volume was recorded as an indicator of this boundary. Coconut oil separated rapidly into two layers, olive oil formed short-lived cloudy dispersions, and baby oil showed similar behavior with slight temperature changes, possibly due to slow interaction with hypochlorite. The results confirm that both oil type and composition ratio strongly govern observable phase behavior in oil–water–NaOCl ternary systems.
Effect of Temperature on the Substitution Equilibrium of Longan, Beetroot, and Coconut Juice on the Total Acid Content and Vitamin C Content of Cow's Milk Yogurt
Variations in fermentation temperature and types of fruit juice added to yogurt affect the acid content, pH, and vitamin C content. This study analyzed yogurt with the addition of longan, beetroot, and coconut juice at fermentation temperatures of 35°C, 40°C, and 45°C. The results showed that beetroot juice had a stable acid content at all temperatures, while longan and coconut juices fluctuated. Increasing the fermentation temperature generally decreased the pH due to acid production by lactic acid bacteria, with pH stabilization occurring at a temperature of 40°C. Vitamin C content increased with increasing fruit juice concentration, but decreased during fermentation due to oxidation, with the greatest decrease in 12-hour fermentation. Beetroot juice was more stable in maintaining acid and vitamin C levels than longan and coconut juices. These results indicate that the selection of fruit juice types and fermentation temperatures is very important in maintaining the quality of yogurt.
Corrosion Reaction Kinetics of Rusty Iron in HCl, H₂SO₄, and NaOH: Determination of Reaction Order and Dissolution Rate
Corrosion is the degradation of metals resulting from chemical interactions with their surrounding environment, leading to significant impacts on industrial systems and infrastructure. This study investigates the corrosion kinetics of rusted iron in hydrochloric acid (HCl), sulfuric acid (H₂SO₄), and sodium hydroxide (NaOH) solutions by determining dissolution rates and reaction order. The corrosion behavior was evaluated using a mass loss method, in which the initial and final masses of rusted iron were measured after immersion in solutions of varying concentrations and exposure times. The results indicate that H₂SO₄ exhibits the highest dissolution rate, followed by HCl, while NaOH shows the lowest corrosion activity. Kinetic analysis reveals that the dissolution process follows first-order reaction kinetics. Furthermore, increasing acid concentration significantly accelerates the corrosion rate, whereas alkaline conditions result in comparatively slower iron dissolution.
The Effect of Composition, Temperature, and Mole Fraction on Solubility in Ternary Diagram of Oil, Water, Soapnuts (Sapindus Rarak DC.)
This study analyzed the effect of composition, temperature, and mole fraction on solubility in a three-component equilibrium system consisting of oil, water, and soapnuts (Sapindus rarak DC.) as a natural surfactant. The study was conducted by extracting soapberry through boiling and titrating at temperatures of 30°C, 50°C, and 70°C with oil-surfactant ratios (1:5, 2:4, 3:3, 4:2, and 5:1). The volume of water to the turbidity point was measured to observe solubility. The results showed that the composition ratio and temperature affected solubility. Increasing the oil ratio required more water for the emulsion, while a higher surfactant ratio stabilized the emulsion. Higher temperatures increased solubility, but extreme temperatures caused phase separation. The optimal ratio for a stable emulsion was 3:3 at 70°C with the lowest water volume (1.3 mL). This study produced a ternary diagram depicting the solubility region.
Effect of Fixatives on the Thermal Stability of Perfume Formulations from Rose, Jasmine, and Frangipani Extracts
Perfume is a mixture of aromatic compounds, essential oils, fixatives, and solvents designed to produce a long-lasting aroma. This study investigated the effect of temperature on the stability of jasmine, rose, and frangipani flower extracts in perfume formulations using benzyl alcohol and benzyl salicylate as fixatives. Essential oils were extracted using the leaching method, and aroma and mass stability were evaluated at 25 °C, 50 °C, and 70 °C. Jasmine extract showed high volatility at all temperatures, with significant mass loss. Rose extract exhibited greater thermal stability than jasmine and frangipani. In contrast, frangipani extract experienced the highest mass reduction, particularly at 70 °C, indicating high temperature sensitivity. Benzyl alcohol reduced evaporation but was less effective at high temperatures, whereas benzyl salicylate provided better aroma stabilization. Hedonic testing showed that jasmine and rose perfumes were preferred. These results demonstrate that fixative selection plays a crucial role in improving perfume aroma durability.
A Review: Modified Graphene-Based Voltammetric Sensors for Heavy Metal Detection in Water Samples
Heavy metal contamination in aquatic environments poses a serious environmental and public health concern, requiring analytical methods that are sensitive, selective, and suitable for on-site analysis. Voltammetric electrochemical sensors have emerged as a promising alternative to conventional techniques due to their low cost, portability, rapid response, and high sensitivity. Graphene, with its high surface area, excellent electrical conductivity, and chemical stability, has been widely utilized as an electrode material to enhance sensor performance. However, pristine graphene often exhibits limited selectivity toward specific metal ions. To address this limitation, various surface modification strategies have been developed, including functionalization with chelating ligands, ion-selective polymers, nanoparticles, and composite materials. This review provides a comprehensive overview of recent advances in modified graphene-based voltammetric sensors for heavy metal detection in water samples, covering voltammetric principles, graphene modification strategies, analytical performance, and practical environmental applications.
Utilization of Coconut Shell Activated Carbon as an Eco-Friendly Adsorbent for Cu(II) Remediation in a Continuous Column System
Copper (II) contamination in aquatic environments poses severe toxic risks. This study investigates the use of coconut shell-activated carbon as an eco-friendly adsorbent for Cu(II) remediation in a continuous column system. Coconut shell was prepared via carbonization at 400–500°C, followed by 0.1 M NaOH activation. FTIR and SEM analysis confirmed the presence of active functional groups (O–H, C=O, C–O) and a porous morphology suitable for ion diffusion. Continuous adsorption trials, conducted at a flow rate of 25 mL/min with 100 mg/L Cu(II), showed that performance increased with contact time. The system achieved a maximum adsorption capacity of 2.390 mg/g and 15.948% effectiveness at 25 minutes. Consequently, coconut shell-activated carbon demonstrates significant potential as a cost-effective adsorbent for continuous heavy-metal wastewater treatment. Keywords: Activated Carbon, Coconut Shell, Adsorption, Continuous Column System
The Improvement of Mechanical Properties of PCL/Microcellulose Biocomposites from Corn Cobs by Adding PCLacac as a Compatibilizer
Biocomposites have wide potential in eco-friendly packaging, agriculture, and biomedical applications such as scaffolds and drug delivery. This study uses poly(ε-caprolactone) (PCL) as a biocompatible, flexible matrix and microcellulose from corn cobs as a renewable, abundant, and low-cost filler. The PCL–microcellulose combination is expected to improve mechanical properties while adding value to agricultural waste. To enhance compatibility between matrix and filler, short-chain synthetic PCL (PCLacac) was added at 0%, 2.5%, 7.5%, and 10%. Serving as a compatibilizer, PCLacac promotes interaction with cellulose hydroxyl groups. The prepared biocomposites were molded according to ASTM D638 standards and characterized. Tensile results showed that the addition of 2.5% PCLacac gave the highest increase in tensile strength. FTIR analysis confirmed hydrogen bonding between PCL carbonyl and cellulose hydroxyl groups, indicated by absorption band shifts. Thus, optimal PCLacac addition (2.5%) enhances mechanical performance and transforms low-value corn cob waste into high-value biocomposites.
Biocomposite, cellulose, compatibilizer, corn cob, PCL
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.
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.
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 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.
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.
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.
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.
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.
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).