Jurnal Kimia dan Rekayasa

Kinetics of Irreversible Saponification Reactions in terms of changes in Reactant Concentration

Dwi Indah Lestari, Debi Anggun Sari, Zeolita Prabu Putri, Isma Uly Maranggi — Mon, 26 Jan 2026 00:00:00 +0700

This study aims to investigate the kinetics of the irreversible saponification reaction between triglycerides in cooking oil and sodium hydroxide (NaOH) by analyzing the changes in reactant concentrations over time. The reaction was carried out at 60 ^oC, and samples were collected every 5 minutes and analyzed by titration using 0.5 M HCl. The results showed that the concentration of NaOH decreased from 0.500 mol/L to 0.290 mol/L within 30 minutes, while triglycerides decreased from 0.203 mol/L to 0.133 mol/L. The kinetic data were evaluated using both second-order and pseudo first-order models to determine the most appropriate mechanism. The second-order model yielded an R² value of 0.9069 with a rate constant of 0.0125 L-mol^-1·min^-1, whereas the pseudo first-order model exhibited better linearity with an R² of 0.9296 and a rate constant of 0.0169 min^-1. These results indicate that although the reaction is mechanistically bimolecular, the experimental conditions particularly the relative excess of NaOH caused the reaction to behave in accordance with pseudo first-order kinetics. Thus, the observed kinetic behavior is more accurately described by the pseudo first-order model, in which the decrease in triglyceride concentration plays a dominant role in controlling the reaction rate. This study provides further insight into the kinetic characteristics of saponification under laboratory operating conditions.

Abstrak
Penelitian ini bertujuan untuk mempelajari kinetika reaksi saponifikasi irreversible antara trigliserida dalam minyak goreng dan natrium hidroksida (NaOH) melalui analisis perubahan konsentrasi reaktan terhadap waktu. Reaksi dijalankan pada suhu 60 ^oC, dan sampel diambil setiap 5 menit untuk dianalisis melalui titrasi menggunakan HCl 0,5 M. Hasil pengamatan menunjukkan bahwa konsentrasi NaOH menurun dari 0,500 mol/L menjadi 0,290 mol/L dalam 30 menit, sedangkan trigliserida turun dari 0,203 mol/L menjadi 0,133 mol/L. Data kemudian dianalisis menggunakan model kinetika orde dua dan pseudo first-order untuk menentukan mekanisme reaksi yang paling sesuai. Model orde dua memberikan nilai R² sebesar 0,9069 dengan konstanta laju 0,0125 L-mol^-1·min^-1, sedangkan model pseudo first-order menunjukkan linearitas lebih baik dengan R² 0,9296 dan konstanta laju 0,0169 min^-1. Perbedaan ini menunjukkan bahwa meskipun reaksi secara mekanistik bersifat bimolekuler, kelebihan relatif NaOH menyebabkan reaksi tampak mengikuti pola pseudo first-order. Dengan demikian, kinetika teramati lebih akurat dijelaskan oleh model pseudo first-order, dimana penurunan konsentrasi trigliserida menjadi faktor pengendali utama laju reaksi. Hasil penelitian ini memperkuat pemahaman mengenai perilaku kinetika saponifikasi pada kondisi operasi laboratorium.

Mediated Electrochemical Oxidation with Lead as Electrode for Organic Waste Treatment from Pulp Industry

Haryono, Juliandri, Atiek Rostika Noviyanti, Irwan Kurnia — Mon, 26 Jan 2026 00:00:00 +0700

The pulp industry is a type of industry based on natural materials, namely lignocellulose, which produces relatively large amounts of organic liquid waste. The use of various types of synthetic chemicals in the pulp production process results in waste from this industry being classified as hazardous and toxic waste. Various methods of liquid waste treatment can be applied, one of which is the Mediated Electrochemical Oxidation (MEO) method. The MEO method allows organic compounds in liquid waste to be oxidized into simple and relatively environmentally friendly inorganic compounds, such as carbon dioxide and water. The purpose of this study was to determine the effect of the potential difference between electrodes and time on the performance of the MEO method with lead electrodes in the treatment of organic liquid waste from the pulp industry. The potential difference between electrodes was studied at values of 3.0, 4.5 and 6.0 volts, while the electrolysis time in MEO was studied for 60, 90 and 120 minutes. The performance of the MEO method in the treatment of organic liquid waste was determined based on the degradation efficiency parameters. The results showed that the maximum degradation efficiency of organic waste was achieved when MEO was carried out at a potential difference between electrodes and an electrolysis time of 6.0 volts and 120 minutes. Under these MEO operating conditions, an organic waste degradation efficiency of 99.03% was achieved.

Abstrak
Industri pulp merupakan salah satu jenis industri berbasis bahan alam, yaitu lignoselulosa, yang menghasilkan limbah cair organik relatif banyak. Pemanfaatan berbagai jenis bahan kimia sintetik pada proses produksi pulp mengakibatkan limbah dari industri tersebut termasuk sebagai limbah berbahaya dan beracun. Berbagai metode pengolahan limbah cair dapat diterapkan, salah satunya adalah metode Oksidasi Elektrokimia Termediasi (OET). Metode OET memungkinkan senyawa organik pada limbah cair untuk dioksidasi menjadi senyawa anorganik sederhana dan relatif ramah lingkungan, seperti karbon dioksida dan air. Tujuan penelitian ini adalah menentukan pengaruh beda potensial antar elektroda dan waktu terhadap kinerja metode OET dengan elektroda timbal pada pengolahan limbah cair organik dari industri pulp. Beda potensial antar elektroda dipelajari pada nilai 3,0, 4,5 dan 6,0 volt, sedangkan waktu elektrolisis pada OET dipelajari selama 60, 90 dan 120 menit. Kinerja metode OET pada pengolahan limbah cair organik ditentukan berdasarkan parameter efisiensi degradasi. Hasil penelitian menunjukkan bahwa efisiensi degradasi limbah organik maksimum dicapai ketika OET dilakukan pada beda potensial antar elektroda dan waktu elektrolisis sebesar 6,0 volt dan 120 menit. Pada kondisi operasi OET tersebut dicapai efisiensi degradasi limbah organik sebesar 99,03%.

HCL Activate Concentration Effect On Nanoporied Active Carbon Powder Of Sugarcane Bagasse And Contact Time For Adsorption Of Heavy Metal Lead Pb (II)

Narimo, Peni Pujiastuti, Tri Wijayanti — Mon, 26 Jan 2026 00:00:00 +0700

This far, bagasse waste has only been used as fuel, in its development can also be used as activated carbon for the adsorption of heavy metals including lead Pb (II). The making nanoporous activated carbon from bagasse are first by drying in the sun, after that crushing it , carbonizing it using a furnace at 300 ⁰C, and activating it with HCL and ultrasonic irradiation using sonication. The results of characteristic testing of nano-porous activated carbon powder showed with irradiation taking place at ultrasonic with an amplitude of 40%, namely an average pore radius of 3.3202 e+01 ⁰A, a surface area of 80.235 m²/ gr and a water content of 0.71%.
The adsorption test results with the sample solution of Pb(NO₃)₂ concentration 100 ppm with each variation HCL 1 N, 2 N, 3 N, 4 N, 5 N, 6 N and the results were tested by Atomic Absorption Spectrophotometry, indicating that the best concentration of HCL solution was 5 N which was able to reduce sample content of Pb (II) was 99.71%. The same thing was done for testing samples of Pb(NO₃)₂ solution with each variable activation time of activated carbon 1, 2 , 3 and 4 hours. The test results show that the best activated carbon activation time is 3 hours which can reduce the concentration of Pb (II) samples by 99.68%.

Abstrak
Limbah Ampas tebu selama ini banyak digunakan hanya untuk bahan bakar penghasil energi panas dalam bentuk uap ( steam boiler ) pada pabrik gula, tetapi pada perkembangan berikutnya ampas tebu juga dapat dimanfaatkan sebagai karbon aktif untuk adsorpsi logam berat termasuk timbal Pb (II). Tahapan pembuatan karbon aktif nanopori dari ampas tebu dimulai dengan preparasi bahan baku yaitu pengeringan dibawah sinar matahari kemudian bahan di crusher, dikarbonisasi menggunakan furnace pada suhu 300 ⁰C, diaktivasi dengan aktivator HCL dan iradiasi ultrasonik memakai sonikasi. Hasil pengujian karakteristik serbuk karbon aktif nanopori dari ampas tebu menunjukkan pembentukan pori pada karbon aktif dengan iradiasi berlangsung pada gelombang ultrasonik dengan amplitudo 40 % yaitu radius pori rata rata 3.3202 e+01 ⁰A, luas permukaan 80.235 m²/ gram dan kadar air 0,71 %. Untuk hasil pengujian adsorpsi dengan sampel larutan Pb(NO₃)₂ konsentrasi 100 mg/L ( 100 ppm ) dengan masing masing variasi konsentrasi aktivator larutan HCL yaitu 1 N, 2 N, 3 N, 4 N, 5 N, 6 N dan hasilnya diuji dengan Spektrofotometri Atom Serapan (AAS) menunjukkan bahwa konsentrasi aktivator larutan HCL terbaik adalah 5 N, mampu menurunkan kadar sampel Pb (II) sebesar 99,71 %. Hal yang sama dilakukan untuk pengujian sampel larutan Pb(NO₃)₂dengan masing masing variabel lama waktu aktivasi karbon aktif yaitu 1 jam, 2 jam, 3 jam dan 4 jam, hasil pengujian menunjukkan bahwa waktu aktivasi karbon aktif terbaik adalah 3 jam mampu menurunkan kadar sampel Pb (II) sebesar 99,68 %.

Biodegrability Analysis Of Banana Stem Fiber And Polyethlene Terephthalate (PET) Polymer Composite As A Substitute For Styrofoam

Rahma Ayu Syafitri, Tri Widayatno — Mon, 26 Jan 2026 00:00:00 +0700

This study aims to examine the potential of banana stem fiber and polyethylene terephthalate (PET)-based composites as biodegradable materials to replace styrofoam. Banana stem fibers are used as natural reinforcement materials combined with PET and PLA resin, with variations in fiber length (2 cm and 6 cm) and composition ratios (10:90, 40:60, 55:45, and 70:30). The composite manufacturing process was carried out using the hand lay-up method, then tested through biodegradability tests, tensile tests, and electron microscopy (SEM) characterization. The results of the biodegradability test showed that the composite variation with a ratio of 10:90 and a fiber size of 6 cm had the highest degradation rate of 11.81%. In the tensile test, the highest strength value was recorded at 13.16 MPa in the same variation. The results of the strain and elastic modulus tests also showed that the composition and size of the fibers affected the mechanical properties of the composite. Meanwhile, the results of SEM characterization showed varying interactions between the fibers and the matrix. These results demonstrate that the banana stem fiber and PET composite has the potential to be an environmentally friendly alternative packaging material, demonstrating mechanical properties and biodegradability that support its application as a replacement for Styrofoam.

Abstrak
Penelitian ini bertujuan untuk mengkaji potensi komposit berbasis serat batang pisang dan polyethylene terephthalate (PET) sebagai material biodegradable pengganti styrofoam. Serat batang pisang digunakan sebagai bahan penguat alami yang dikombinasikan dengan PET dan resin PLA, dengan variasi panjang serat (2 cm dan 6 cm) serta rasio komposisi (10:90, 40:60, 55:45, dan 70:30). Proses pembuatan komposit dilakukan menggunakan metode hand lay-up, kemudian diuji melalui uji biodegrabilitas, uji tarik, dan karakterisasi mikroskop elektron (SEM). Hasil pengujian biodegrabilitas menunjukkan bahwa variasi komposit dengan rasio 10:90 dan ukuran serat 6 cm memiliki laju degradasi tertinggi sebesar 11,81%. Pada uji tarik, nilai kekuatan tertinggi tercatat sebesar 13,16 MPa pada variasi yang sama. Hasil uji regangan dan modulus elastisitas juga menunjukkan bahwa komposisi dan ukuran serat berpengaruh terhadap sifat mekanik komposit. Sementara itu, hasil karakterisasi SEM memperlihatkan interaksi yang bervariasi antara serat dan matriks. Dengan hasil tersebut, komposit serat batang pisang dan PET memiliki potensi sebagai alternatif bahan pengemas yang ramah lingkungan serta menunjukkan sifat mekanik dan biodegrabilitas yang mendukung aplikasinya sebagai pengganti styrofoam.