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Equilibrium Journal of Chemical Engineering
Published by Universitas Sebelas Maret
ISSN : -     EISSN : 26223430     DOI : https://dx.doi.org/10.20961/equilibrium.v4i1.42852
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Chemistry Energy Engineering Materials Science & Nanotechnology
Equilibrium Journal of Chemical Engineering (EJChE) publishes communication articles, original research articles and review articles in :. Material Development Biochemical Process Exploration and Optimization Chemical Education Chemical Reaction Kinetics and Catalysis Designing, Modeling, and Process Optimization Energy and Conversion Technology Thermodynamics Process System Engineering and products Membrane Technology Food Technology Bioprocess Technology Chemurgy Technology Waste Treatment Technology Separation and Purification Technology Natural Dyes Technology
Arjuna Subject : Teknik Kimia (semua kategori) - Kimia Proses dan Teknologi
Articles 98 Documents
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Preparation and Flocculation Performance of Polyacrylamide Grafted Banana Stem Cellulose: Effect of Acrylamide and Ammonium Peroxydisulfate Distantina, Sperisa; Nainggolan, Imanuel Daniel; Fernando, Yosea Ido; Kaavessina, Mujtahid
Equilibrium Journal of Chemical Engineering Vol 9, No 2 (2025): Volume 9, No 2 December 2025
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v9i2.110187

Abstract

ABSTRACT. Banana stem was identified as an attractive source of cellulose and a promising raw material for developing friendly bioflocculant hydrogels in water treatment. Polyacrylamide grafted banana stem cellulose (BS-g-PAA) was synthesized for flocculation application. The objective of this study was to investigate the effect of ammonium peroxydisulfate (APS) and acrylamide (AA) amount on the grafting efficiency and flocculation performance of obtained BS-g-PAA. In this study, 1 g banana stems flour was mixed in distilled water, followed by the addition of AA at different weight (10, 15, and 20 g) and APS at various weight (0.1, 0.15, and 0.2 g). The mixture was grafted using microwave irradiation at 540 W for 60 s per cycle, repeated for three cycles (total 180 s). The sample was then dried using an oven until constant weight and ground to obtain BS-g-PAA powder. The results of FTIR showed that the successful grafting of acrylamide onto the cellulose backbone. The grafting percentage increased with the increasing of AA amount, from 1,008% at 10 g AA to 2,098% at 20 g AA. Ammonium peroxydisulfate from 0.1 g to 0.2 g increased grafting percentage from 980% to 1,008%. BS-g-PAA hydrogel prepared by 1 g banana stem, 0.2 g APS, and 10 g AA produced the most effective turbidity reduction by reducing the turbidity value from 53.3 NTU of kaolin suspension to a final value of 15.29 NTU after 80 s flocculation test. These results demonstrated that hydrogels derived from banana stems may have promising potential as sustainable bioflocculants for wastewater treatment applications.Keywords:Banana stem, Ammonium peroxydisulfate, Acrylamide, Bioflocculant, Microwave grafting
Effect of Caffeine Adsorption by Activated Charcoal in Green Coffee Extract on Blood Glucose Reduction in Rats Arvianto, Rizky Ibnufaatih; Suhirman, Suhirman; Sunaryo, Tri
Equilibrium Journal of Chemical Engineering Vol 9, No 2 (2025): Volume 9, No 2 December 2025
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v9i2.107709

Abstract

ABSTRACT. Green coffee beans (Coffea Canephora) contain chlorogenic acid, an active compound known to aid in lowering blood glucose levels. However, the caffeine content in green coffee beans can reduce insulin sensitivity, thereby diminishing glucose tolerance. This study aims to improve the hypoglycemic potential of green coffee by removing caffeine through adsorption using activated carbon. Green coffee beans were extracted in water at 60–70°C, and caffeine adsorption was carried out with activated carbon. FTIR analysis was performed on the activated carbon to confirm caffeine adsorption, while HPLC analysis was conducted on the green coffee extract before and after adsorption to determine caffeine and chlorogenic acid contents. Hypoglycemic activity was evaluated in alloxan-induced albino Wistar rats (150–250 g). Statistical analysis using the t-test was employed to assess the effectiveness of caffeine adsorption in lowering blood glucose levels. Activated carbon reduced caffeine content by 23.71%, as confirmed by FTIR spectra showing hydrogen bonding interactions between the –OH groups of activated carbon and the C=O or N atoms of caffeine. Rats receiving the caffeine-reduced green coffee extract reached normal blood glucose levels faster than untreated diabetic rats. The effectiveness of caffeine adsorption was supported by the t-test results, which showed a significant reduction in mean blood glucose levels compared with the untreated diabetic group (p = 0.002) and from baseline values (p = 0.004). Although the treated diabetic group still differed significantly from the normal control (p = 0.021), the glucose level approached the normal range, indicating substantial recovery toward normoglycemia.Keywords:Green coffee beans, Caffeine, Chlorogenic acid, and Blood glucose
Comparative Study of Machine Learning Algorithms for Cr(VI) Adsorption Optimization: A Case Study Using KOH-Activated Wood Charcoal Afandy, Moh. Azhar; Sawali, Fikrah Dian Indrawati
Equilibrium Journal of Chemical Engineering Vol 10, No 1 (2026): Volume 10, No 1 July 2026 (First Online)
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v10i1.108769

Abstract

The removal of toxic Cr(VI) ions from industrial wastewater remains a pressing environmental concern due to their high mobility and carcinogenic nature. This study presents a data-driven approach for modeling and optimizing Cr(VI) adsorption onto KOH-activated wood charcoal using various machine learning (ML) algorithms. A dataset derived from batch adsorption experiments was used, involving three operational parameters: initial Cr(VI) concentration (10–50 mg/L), contact time (40–120 min), and adsorbent dose (0.5–1.5 g). Six supervised regression models such as Linear Regression, Decision Tree, Random Forest, Support Vector Machine (SVM), Gradient Boosting, and k-Nearest Neighbors (kNN) were evaluated. Model performance was assessed using the coefficient of determination (R²), root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE) dan mean square error (MSE). Gradient Boosting and Decision Tree showed superior predictive accuracy, with R² values of 0.89 and 0.87, respectively. Feature importance analysis revealed initial concentration as the most influential factor, followed by contact time and adsorbent dosage. These findings highlight the potential of ML as an effective tool for predicting and optimizing adsorption processes in environmental remediation. The integration of ML methods supports efficient decision-making, particularly under constraints of limited experimental data, and aligns with digital transformation strategies in wastewater treatment.
Modification of Sago Starch Through Lintnerization and Its Impact on Biodegradable Straw Properties Setyawardhani, Dwi Ardiana; Putri, Sinta Kristiana; Nisa, Putri Fadilla; Hidayati, Fikriyyah Nur; Sutoyo, Hananda Christy
Equilibrium Journal of Chemical Engineering Vol 10, No 1 (2026): Volume 10, No 1 July 2026 (First Online)
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v10i1.104868

Abstract

The increasing environmental burden caused by plastic waste necessitates the exploration of sustainable alternatives such as starch-based biodegradable products. Sago starch, a renewable polysaccharide offers potential for such applications. However, its inherent limitations such as poor thermal stability and water resistance restrict its use in biodegradable product. This study investigates the effect of lintnerization, a mild acid hydrolysis process on the physicochemical properties of sago starch and evaluates its performance in biodegradable straw production. Sago starch was modified through a 120-hour lintnerization process using 2.2 N HCl, followed by washing and drying to obtain crystalline starch. The resulting starch was characterized by XRD and SEM, and its application in straws was assessed via yield, organoleptic tests, tensile strength, water resistance, and biodegradability. The yield of crystalline starch reached 99.89%, with organoleptic scores indicating good visual and textural quality. XRD analysis revealed an increase in crystallinity from 33.32% to 49.98%, while SEM confirmed significant granule degradation. Incorporating crystalline starch improved straw water resistance up to 83.65% and tensile strength up to 7.05 MPa fulfilling industry standards. However, the biodegradability test results were unreliable due to uncontrolled external factors. These findings demonstrate that lintnerization enhances starch performance for biodegradable applications.
Machine Learning vs. Real-World Data: Assessing ANN Performance in COD Removal in Animal Feed Processing Wastewater Pertiwi, Beta Cahaya; Tirkaamiana, Dean; Matovanni, Maudy Pratiwi Novia; Sumada, Ketut
Equilibrium Journal of Chemical Engineering Vol 9, No 1 (2025): Volume 9, No 1 July 2025
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v9i1.104192

Abstract

This research established an artificial neural network (ANN) aimed at optimizing ozonation for chemical oxygen demand (COD) reduction in animal feed plant wastewater. Experimental data (200-1000 mg/L COD, 100-180 min treatment) were used to train a 10-8 neuron artificial neural network, resulting in a predicted removal rate of 97.4% at 180 minutes for 1000 mg/L COD (MSE=15.9, R²=0.34).  Experiments indicated a marginally higher efficiency of 97.83% at 160 minutes; however, the ANN's conservative recommendation of 180 minutes is more appropriate for industrial scalability. The model successfully identified non-linear degradation patterns of recalcitrant organics, illustrating the potential of artificial neural networks for optimizing wastewater treatment.  This study connects laboratory research with industrial application via machine learning, establishing a framework that balances efficiency and operational practicality. Future improvements may integrate real-time process data to increase accuracy.
Utilization of Bacterial Cellulose of Nata de Soya as an Alternative Raw Material for Honeycomb Paper Wrap Azis, Denisda Nabhan; Aziza, Sharfina Rani; Puspitaningtyas, Isnania; Putra, Mohammad Syafiq Alika; Margono, Margono
Equilibrium Journal of Chemical Engineering Vol 9, No 1 (2025): Volume 9, No 1 July 2025
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v9i1.92905

Abstract

ABSTRACT. The growing production of wood-based paper has contributed to deforestation and environmental pollution, underscoring the urgent need for alternative, sustainable raw materials. Bacterial cellulose derived from nata de soya presents a promising non-wood source for paper production. This study investigated the utilization of bacterial cellulose from nata de soya as a raw material for honeycomb paper wrap applications. Bacterial cellulose obtained from 18-day-old nata de soya was processed into paper with the addition of kaolin and tapioca as functional additives. Four formulations were evaluated: Formula 1 (100% bacterial cellulose), Formula 2 (62% bacterial cellulose and 38% kaolin), Formula 3 (76% bacterial cellulose and 24% tapioca), and Formula 4 (52% bacterial cellulose, 32% kaolin, and 16% tapioca). The resulting papers were characterized in terms of thickness, grammage, moisture content, tensile strength, and load-bearing capacity. The results demonstrated that Formula 4 exhibited the most favorable performance, with a thickness of 0.43 mm and a grammage of 191 g/m², complying with packaging paper standards (SNI 8218:2015). The moisture content was 5.66%, within the acceptable limit specified by SNI 7274:2008, and the tensile strength reached 1.659 kN/m, exceeding the minimum standard requirement. Furthermore, the honeycomb paper wrap produced using Formula 4 showed a load-bearing capacity comparable to that of commercial products. These findings indicate that bacterial cellulose paper formulated with a combination of kaolin and tapioca has strong potential as a sustainable alternative material for honeycomb paper wrap.Keywords:Bacterial cellulose, Deforestation, Honeycomb paper wrap, nata de soya, Tofu wastewater
Synthesis and Application of Coconut Shell Activated Carbon Fe3O4 Composite for Zn2+ Metal Ion Adsorption from Wastewater Rahadianto, Wahyu Triaji; Sugesti, Heni; Chandra, Yogi
Equilibrium Journal of Chemical Engineering Vol 9, No 2 (2025): Volume 9, No 2 December 2025
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v9i2.111786

Abstract

Abstract. Industrial wastewater containing heavy metals such as Zn²⁺ ions is one of the hazardous pollutants that can pose serious risks to the environment and human health. The presence of Zn²⁺ in aquatic systems at high concentrations can lead to acute toxicity, thus requiring effective and sustainable treatment methods. Adsorption has become one of the most widely developed treatment approaches due to its advantages, including high efficiency, low operational cost, and environmental friendliness. This study aims to synthesize and characterize Fe₃O₄/activated carbon composites as adsorbents for the removal of Zn²⁺ ions from wastewater. Fe₃O₄ was synthesized through a coprecipitation method using FeCl₃·6H₂O and FeSO₄·7H₂O precursors, and subsequently combined with thermally activated coconut-shell carbon to enhance surface area and adsorption capacity. The composite was characterized using X-Ray Diffraction (XRD). Adsorption tests were conducted using various composite masses 0.04 g, 0.05 g, 0.06 g, 0.07 g, and 0.08 g to examine the effect of adsorbent dosage. The best performance was obtained at an adsorbent mass of 0.08 g with an optimum contact time of 75 minutes. Under these conditions, an initial Zn²⁺ concentration of 30 ppm decreased significantly, achieving a maximum removal efficiency of 91% and 84.63% under other test conditions. These findings indicate that the Fe₃O₄/activated carbon composite exhibits high effectiveness and selectivity in adsorbing Zn²⁺ ions and holds strong potential for development as a wastewater treatment material based on renewable and environmentally friendly local resources.Keywords: Activated Carbon, Adsorption, Coconut Shell, Fe₃O₄ Composite, Zn²⁺ Ions
Synthesis and Characterization of Novel Bi-Functional Catalyst from Mixture of Agro-Wastes Using Hydrothermal-Sulphonation Method Nwachukwu, Ifeanyi Michael; Ulakpa, Wisdom Chukwuemeke; Eyide, Odeworitse; Ekpenkhio, Josephine Eguare; Akhabue, Christopher Ehiaguina
Equilibrium Journal of Chemical Engineering Vol 9, No 2 (2025): Volume 9, No 2 December 2025
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v9i2.101280

Abstract

Abstract. This research illustrates the development of a bi-functional catalyst derived from a blend of agricultural waste materials, employing a hydrothermal method. The precursor materials included cocoa pods, eggshells, snail shells, and orange peels. The resulting bi-functional catalyst underwent characterization through a variety of techniques, such as FTIR, XRF, XRD, SEM, TGA-DTA, and both single-point and multi-point BET analyses. The FTIR and XRD analyses distinctly indicated the transformation of calcium carbonate (CaCO3) from the agro-waste precursors into calcium oxide (CaO). XRD further validated the crystalline structures and identified the oxide minerals present within the catalyst using an X-ray diffractometer. The DTA-DSC curve displayed notable endothermic peaks at 400 °C, indicating a decomposition reaction that leads to the formation of a new compound. The surface area of the bi-functional catalyst was assessed using single-point and multi-point Brunauer-Emmett-Teller (BET) methods, yielding values of 87.94 m²/g and 159.4 m²/g, respectively. Additionally, the adsorption surface area of the catalyst's pore size was measured at 165 m²/g, while the Langmuir surface area was found to be 2792 m²/g, as determined by the Barrett-Joyner-Halenda (BJH) method. The mean pore volume was calculated to be 812.5 cc/g, and the average pore diameter was 2.138 nm, as established through BJH analysis. The diverse surface property results underscore the substantial influence of surface area on the catalyst's activity, as a larger surface area facilitates more efficient interactions between reactants and active sites. Consequently, the agricultural waste materials represent a promising source of calcium oxide for various applications across numerous scientific and engineering disciplines. Keywords: Bi-functional, Cocoa pods, Eggshells, Snail shells, Orange peels 
Synthesis of Gelatin-Free Halal Capsule Shells Based on Microcrystalline Cellulose from Solid Sugar Palm (Aren) Waste Pradaniz, Erika Putri; Prawesti, Widya Ayu; Iwahyuningtyas, Intan; Naufiannida, Nasywa Alya; Maharani, Anggistia; Fadilah, Fadilah
Equilibrium Journal of Chemical Engineering Vol 9, No 2 (2025): Volume 9, No 2 December 2025
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v9i2.105387

Abstract

ABSTRACT. Capsules are one of the most used drug delivery media. Capsule shells are made from gelatin, a protein derived from hydrolyzed collagen, which is extracted from animal skin, tissue, and bones. Gelatin from animals is susceptible to contamination with pathogens. Alternative ingredients that are safe to use include those derived from vegetables, such as palm starch dregs. The cellulose content in solid sugar palm waste is quite high, so it has potential for use in making capsule shells. However, cellulose does not dissolve easily in water. Improving this property can be done by changing the size. Microcrystalline Cellulose (MCC) is obtained by acid hydrolysis of cellulose, resulting in the loss of the amorphous portion, leaving the crystalline portion. Its good dispersion in water makes MCC a matrix-forming agent when mixed with HPMC, a gelatin substitute. This research intends to examine the impact of involving MCC derived from solid sugar palm waste on the characteristics of the capsule shell. The properties include uniformity of weight, water content, ash content, pH, and solubility. The acid hydrolysis method is used in the synthesis of MCC. FTIR results show that MCC has the same functional groups as α-cellulose. SEM results show that although some parts are nano-sized, there are still other parts that are micron-sized. Capsule shells were made with varying concentrations of MCC 1%, 4%, 7%, and 10% with the addition of HPMC 2%, PEG-400 2%, and water. The results show that the best variation is at 4% MCC, which meets the standards of Farmakope Indonesia VI edition. On average, the capsule’s weight is 0.0938 grams, water content is 13.73%, ash content is 1.35%, pH 6, solubility in water is 19 minutes 49 seconds, and solubility in acid is 2 minutes 40 seconds.Keywords:α-selulosa, Capsule shell, Microcrystalline celluloses, Drug delivery, Palm starch dregs.
Density Evaluation of Alkyl Ester from Different Types of Alcohol and Vegetable Oil Sawitri, Dyah Retno; Azzam, Khusnul; Isnani, Ani Chalwa; Husein, Darryl Al
Equilibrium Journal of Chemical Engineering Vol 9, No 2 (2025): Volume 9, No 2 December 2025
Publisher : Program studi Teknik Kimia UNS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/equilibrium.v9i2.107798

Abstract

ABSTRACT. Alkyl ester, also known as biodiesel, is an alternative renewable energy source and is produced through the reaction of vegetable oil and alcohol. One of the important characteristics of biodiesel lies in the density value. This study evaluates the density value of alkyl esters from several raw materials. The raw materials used include palm oil and rice bran oil. In comparison, the types of alcohol used include methanol, ethanol, and isopropanol. The density values of palm oil ethyl ester and rice bran oil ethyl ester were measured at 30 – 100°C. The density measurement results were then compared with the simulation results using ASPEN Plus® software. The density of alkyl esters was measured over a temperature range of 30-100°C. The density measurements were then compared with the simulation results using ASPEN Plus® software. The measurement and simulation results showed that the density was higher in the order ethyl > methyl > isopropyl ester for palm oil. When viewed from the vegetable oil, the density of rice bran oil ethyl ester is higher than that of palm oil ethyl ester. The results of measuring biodiesel from rice bran oil and palm oil at 40°C show that only the isopropyl ester has a density that does not meet the quality requirements of biodiesel as defined by the Indonesian National Standard. Keywords:Biodiesel, Density, Palm oil, Rice bran oil 

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