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ALCHEMY Jurnal Penelitian Kimia
Published by Universitas Sebelas Maret
ISSN : 14124092     EISSN : 24434183     DOI : -
Core Subject : Science, Social, Engineering,
Chemical Engineering, Chemistry & Bioengineering Chemistry Energy Environmental Science Materials Science & Nanotechnology
ALCHEMY Jurnal Penelitian Kimia is a chemistry journal published by Sebelas Maret University, Surakarta. ALCHEMY Jurnal Penelitian Kimia publishes original research articles or review articles in organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry, biochemistry, and environmental chemistry.
Arjuna Subject : -
Articles 281 Documents
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Pengaruh Kadar Free Fatty Acid dalam Used Cooking Oil (UCO) dan Massa Katalis pada Proses Transesterifikasi terhadap Karakteristik dan Kelimpahan Used Cooking Oil Methyl Ester (UCOME) Nina Haryani; Elfrida Rasyidah Desvi Imanda; Andiga Asih Ambarwati Utami
ALCHEMY Jurnal Penelitian Kimia Vol 21, No 1 (2025): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.21.1.84661.94-103

Abstract

Salah satu pemanfaatan kembali minyak jelantah atau Used Cooking Oil (UCO) adalah diolah menjadi biodiesel Used Cooking Oil Methyl Ester (UCOME). Free Fatty Acid (FFA) dalam UCO diolah melalui reaksi transesterifikasi menjadi metil ester. Penelitian ini bertujuan untuk mempelajari pengaruh kadar FFA UCO dan massa katalis terhadap karakteristik dan yield UCOME yang dihasilkan. Variasi kadar FFA UCO yang digunakan yaitu 1,493%; 1,536%; 2,56%; dan 5,504%. Reaksi transesterifikasi dilakukan pada temperatur 60 – 65 ℃, pengadukan 350 rpm, serta rasio mol UCO dan metanol (1:6) dengan variasi massa katalis KOH yaitu 0,5%, 1,5%, dan 2,5% (b/b) UCO. Parameter uji karakteristik UCOME meliputi densitas, viskositas, API Gravity, dan Higher Heating Value (HHV). Analisis komponen kimia dilakukan menggunakan alat Gas Chromatography-Mass Spectrometry (GC-MS). Yield tertinggi sebesar 96,59% diperoleh pada hasil transesterifikasi sampel dengan kadar FFA 1,493%. Massa katalis KOH yang optimal adalah 1,5% (b/b UCO). Hasil GC-MS produk dengan kadar FFA awal <5% didominasi oleh metil ester rantai C11-C19. Karakteristik seluruh produk dengan kadar FFA awal <5% memenuhi standar biodiesel menurut SNI.The Effect of Free Fatty Acid Content in Used Cooking Oil (UCO) and Catalyst Mass in Transesterification Process on Used Cooking Oil Methyl Ester (UCOME)’s Characteristics and Yield. One way to take advantage of Used Cooking Oil (UCO) is by recycling it into Used Cooking Oil Methyl Ester (UCOME) biodiesel. The free fatty acids (FFA) in UCO are processed through a transesterification reaction into methyl esters. This study aims to review the effects of FFA content in UCO and the catalyst mass used on the characteristics and yield of UCOME produced. The variations in FFA content in UCO are 1.493%, 1.536%, 2.56%, and 5.504%. The transesterification reaction was carried out at a condition of 60 – 65 ℃, with stirring at 350 rpm, and mole ratio between UCO and methanol (1:6) with variations in the amount of KOH catalyst at 0.5%, 1.5%, and 2.5% w/w UCO. The UCOME characteristic test parameters include density, viscosity, API gravity, and Higher Heating Value (HHV). The highest yield of 96.59% was obtained from the transesterification of the sample with an FFA content of 1.493%. The optimal amount of KOH catalyst is 1.5% w/w UCO. The GC-MS results of products with initial FFA content <5% are dominated by C11-C19 methyl esters. The characteristics of all products with initial FFA content <5% fulfill the biodiesel standards according to SNI.
Pelapisan Phospolypid Lecithin pada Carbon Quantum Dots (CQDs) dari Tulang Ayam Terkonjugasi Silika Nanopartikel sebagai Penghantar Obat Vicky Ahava Ferdinansyah; Khoirun Nisa Ashar; Husna Habib Musthofa; Farikha Amalina Nurbaiti; Salma Aqilah Rachmadani; Fajar Rakhman Wibowo
ALCHEMY Jurnal Penelitian Kimia Vol 21, No 1 (2025): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.21.1.80594.33-42

Abstract

Pengobatan kanker otak saat ini masih mengandalkan kemoterapi. Pada jaringan otak terdapat blood-brain barrier (BBB) yang menghambat pengiriman obat. Penelitian ini bertujuan untuk mengembangkan sistem penghantaran obat menggunakan Carbon Quantum Dots (CQDs) berbahan dasar tulang ayam terkonjugasi nanopartikel silika terkonjugasi (MSN) dan fosfolipid lesitin sebagai bahan yang potensial dalam mengobati kanker otak. Hasil CQDs yang disintesis secara hidrotermal menunjukkan pendaran cahaya biru di bawah sinar UV 365 nm dan puncak emisi pada 469 nm. MSN disintesis dan dikonjugasikan CQDs dengan metode solgel dan pemuatan doxorubicin (DOX) dengan adsorpsi obat. Pelapisan lipid pada DOX@MSN-CQDs dilakukan dengan teknik hidrasi lipid film dan ultrasonifikasi. Pelapisan lipid dan ukuran material pada MSN-CQDs dikonfirmasi menggunakan TEM dengan ukuran 93,77 ± 4,28 nm, FTIR, dan zeta potensial. Sintesis DOX@MSN-CQDs--L berhasil dilakukan diindikasikan dengan adanya perbedaan secara fisis dengan sifat lebih keruh dan warna yang lebih muda daripada MSN-CQDs. Hasil penelitian ini adalah pemuatan dan pelepasan doxorubicin berhasil dilakukan kapasitas pemuatan lebih dari 50% dan kumulatif pelepasan berkisar 73%. Material yang berhasil disintesis dalam penelitian ini berpotensi untuk diaplikasikan sebagai bahan teranostik dalam pengobatan kanker otak.The Coating of Phospolypid Lecithin on Carbon Quantum Dots (CQDs) Derived from Chicken Bone Conjugated with Silica Nanoparticle as Drug Delivery. Current brain cancer treatment still relies heavily on chemotherapy. However, the presence of the blood-brain barrier (BBB) in brain tissue hinders effective drug delivery. This study aims to develop a drug delivery system using carbon quantum dots (CQDs) prepared from chicken bone conjugated silica nanoparticles (MSN) and lecithin phospholipids as potential material for treating brain cancer. The CQDs synthesized via the hydrothermal method exhibited blue fluorescence under 365 nm UV light and an emission peak at 469 nm. MSN was synthesized and conjugated with CQDs using the sol-gel method, followed by doxorubicin (DOX) loading through drug adsorption. Lipid coating on DOX@MSN-CQDs was performed using the lipid film hydration technique and ultrasonication. The lipid coating and material size of MSN-CQDs were confirmed using TEM, with a size of 93.77 ± 4.28 nm, FTIR, and zeta potential measurements. The successful synthesis of DOX@MSN-CQDs-L was indicated by physical differences, such as a cloudier appearance and lighter color compared to MSN-CQDs. The results demonstrated successful DOX loading and release, with a loading capacity exceeding 50% and a cumulative release of approximately 73%. The materials successfully synthesized in this study have the potential to be applied as theranostic agents in brain cancer treatment.
Skrining Bakteri Termohalofilik Penghasil L-asparaginase dari Sumber Air Panas Wawolesea Sulawesi Tenggara dan Uji Aktivitas Enzimnya Muzuni Muzuni; Jamaluddin Jamaluddin; Suriana Suriana; Ardiansyah Ardiansyah; Nur Arfa Yanti
ALCHEMY Jurnal Penelitian Kimia Vol 20, No 1 (2024): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.20.1.73523.12-21

Abstract

L-asparaginase merupakan enzim yang mengubah L-asparagin menjadi L-aspartat. L-asparagin dapat dimanfaatkan oleh sel kanker leukemia sebagai salah satu sumber nutrisinya. Penambahan L-asparaginase dapat menghambat pertumbuhan sel kanker. Penggunaan L-asparaginase dalam skala industri lebih mengutamakan L-asparaginase yang memiliki aktivitas dan stabilitas optimum di suhu tinggi, karena kecepatan reaksi dalam menghidrolisis L-asparagin tinggi, stabil dari denaturan misalnya detergen dan senyawa organik, dan stabil pada kondisi asam maupun basa. L-asparaginase yang memiliki aktivitas dan stabilitas di suhu tinggi dapat dieksplorasi dari mikroorganisme yang hidup di lingkungan yang bersuhu dan bersalinitas tinggi. Tujuan penelitian ini adalah untuk memperoleh isolat bakteri termohalofilik penghasil enzim L-aparaginase dari sumber air panas Wawolesea dan untuk mengetahui aktivitas enzim L-asparaginase yang dihasilkannya. Bakteri termohalofilik penghasil enzim L-asparaginase diperoleh dengan tahapan: isolasi bakteri pada media NA yang mengandung NaCl 1,5% – 1,6%; seleksi bakteri penghasil L-asparaginase pada media M-9; produksi L-asparaginase dengan prinsip fermentasi pada media produksi serta pengukuran aktivitas dan aktivitas spesifik enzim L-asparaginase. Hasil isolasi menunjukkan adanya 14 isolat bakteri termohalofilik yang mampu menghasilkan enzim L-asparaginase. Aktivitas enzim L-asparaginase tertinggi yaitu 86,61 IU/mL pada isolat AAT3.2 dan terendah yaitu 38,24 IU/mL pada isolat CAT1.1. Aktivitas spesifik tertinggi 6767,98 IU/mg pada isolat CAT3.2 dan terendah 684,54 IU/mg pada isolat CAT1.1.Screening of L-asparaginase-Producing Thermohalophilic Bacteria from Wawolesea Hot Springs in Southeast Sulawesi and Their Enzyme Activity Test. The L-asparaginase is an enzyme that can convert L-asparagine to L-aspartate. L-asparagine can be utilized by leukemia cancer cells as a source of nutrition. The use of L-asparaginase on an industrial scale prioritizes L-asparaginase that exhibits optimal activity and stability at high temperatures due to the high reaction rate in hydrolyzing L-asparagine, stability against denaturants such as detergents and organic compounds, and stability under acidic or basic conditions. L-asparaginase with activity and stability at high temperatures can be explored from microorganisms that live in high-temperature and high-salinity environments. This study aimed to obtain isolates of thermohalophilic bacteria that produce L-asparaginase enzymes from Wawolesea hot springs and determine the activity of the L-asparaginase enzymes. Thermohalophilic bacteria producing L-asparaginase from Wawolesea hot springs were obtained by the following steps: isolation of bacteria on NA (Nutrient Agar) media containing 1.5% – 1.6% NaCl, selection of L-asparaginase-producing bacteria on M-9 media, production of L-asparaginase with the principle of fermentation on production media and measurement of activity and specific activity of L-asparaginase enzyme. The isolation results showed that there were 14 isolates of thermohalophilic bacteria capable of producing L-asparaginase. The highest L-asparaginase enzyme activity was 86.61 IU/mL in AAT3.2 isolates, and the lowest was 38.24 IU/mL in CAT1.1 isolates. The highest specific activity was 6767.98 IU/mg in isolate CAT3.2, and the lowest was 684.54 IU/mg in isolate CAT1.1.
Penggunaan Katalis Nikel Fosfida Berpenyangga Zeolit Alam untuk Optimasi Reaksi Esterifikasi Distilat Asam Lemak Sawit menjadi Biodiesel menggunakan Responce Surface Methodology-Box Behnken Design Isalmi Aziz; Hana Saidah; Adawiah Adawiah; Lisa Adhani
ALCHEMY Jurnal Penelitian Kimia Vol 20, No 2 (2024): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.20.2.86703.178-189

Abstract

Biodiesel merupakan biofuel generasi pertama, bersifat terbarukan, dan ramah lingkungan yang dapat menggantikan bahan bakar diesel. Bahan bakunya dapat berupa distilat asam lemak sawit (DALMS) yang merupakan produk samping pengolahan minyak sawit mentah, memiliki kadar asam lemak tinggi dan bersifat nonedible. Sintesis biodiesel dari DALMS dilakukan melalui reaksi esterifikasi menggunakan katalis nikel fosfida berpenyangga zeolit alam (NiP/Za). Tujuan penelitian ini adalah menentukan karakteristik katalis dan kondisi optimum esterifkasi DALMS menjadi biodiesel menggunakan Response Surface Methodology-Box Behnken Design (RSM-BBD). Zeolit alam diberi perlakuan desilikasi dan aktivasi serta katalis disintesis dengan impregnasi basah. Esterifikasi dilakukan pada waktu 2 – 4 jam, suhu 45 – 65 ℃, konsentrasi katalis 5% – 15% (b/b). Hasil karakterisasi menunjukkan bahwa katalis memiliki fase kristal Ni2P dengan munculnya puncak pada 2θ: 40,5; 44,5; dan 47,21o, ukuran kristal 28,64 nm, luas permukaan 35,577 m2/g, volume pori 0,094 cc/g, dan diameter pori 3,8306 nm. Parameter waktu dan suhu berpengaruh signifikan terhadap konversi. Kondisi optimum esterifikasi DALMS menjadi biodiesel didapatkan pada suhu 45 ℃, waktu 4 jam, dan konsentrasi katalis 6% dengan konversi 4,67%.The Use of Natural Zeolite-Supported Nickel Phosphide Catalyst to Optimize the Esterification Reaction of Palm Fatty Acid Distillate into Biodiesel using Response Surface Methodology-Box Behnken Design. Biodiesel is a renewable and environmentally friendly first-generation biofuel that can replace diesel fuel. The raw material can be Palm fatty acid distillate (PFAD), a by-product of crude palm oil processing, which has a high fatty acid content and is nonedible. An activated natural zeolite-supported nickel phosphide catalyst (NiP/NZ) makes the esterification reaction easier, which turns PFAD into biodiesel. This study aimed to determine the characteristics of the catalyst and the optimum conditions for the esterification of PFAD into biodiesel using the Response Surface Methodology-Box Behnken Design (RSM-BBD). Natural zeolite was desilicated and activated. Then, the catalyst was synthesized by wet impregnation. Esterification was performed for 2 ‒ 4 h at a temperature of 45 – 65 ℃ and a catalyst dosage of 5% – 15% (w/w). The tests revealed that the catalyst consists of Ni2P crystals, exhibiting diffraction peaks at 2θ 40.5, 44.5, and 47.21°. The crystals are 28.64 nm in size, and the catalyst has a surface area of 35.577 m2/g, a pore volume of 0.094 cc/g, and a pore diameter of 3.8306 nm. Time and temperature parameters significantly affected the conversion of PFAD. The optimum condition for PFAD esterification into biodiesel was obtained at 45 ℃, 4 h, and 6% catalyst concentration with 4.67% conversion
Preparasi Karbon Aktif Sekam Padi dan Serbuk Gergaji Kayu Jati melalui Proses Refluks sebagai Adsorben Larutan Multi Ion Fe(II)/Cu(II) Cucun Alep Riyanto; Yohanes Ariesto; Fidelis Tertius Aluh Christyawardana; Yehez Kiel Sandy Pradana; Nicho Vernanda Wina Puspita; Iga Permata Sari; Jose D Michael Yonggulemba; Marturia Ester Tumbelaka; Sarawinda Hutagalung; Fuady Hanief; Wawan Rustyawan
ALCHEMY Jurnal Penelitian Kimia Vol 21, No 1 (2025): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.21.1.92401.104-120

Abstract

Sekam padi dan serbuk gergaji kayu jati merupakan bahan berlignoselulosa yang berpotensi sebagai bahan karbon aktif. Penelitian ini bertujuan untuk menentukan pengaruh proses refluks terhadap karakter karbon aktif sekam padi (RHAC) dan serbuk gergaji kayu jati (TSAC) sebagai adsorben. Sekam padi dan serbuk gergaji kayu jati dikarbonisasi pada suhu 400 °C lalu direfluks menggunakan larutan NaOH 2 N pada suhu 100 °C. Karbon diimpregnasi dengan rasio karbon:H3PO4 1:3 (b/b). Karbon aktif RHAC/TSAC diaplikasikan menjerap multi ion Fe(II)/Cu(II) diikuti studi kinetika dan isoterm adsorpsinya. Hasil penelitian menunjukkan karbon aktif RHAC dan TSAC memiliki gugus aktif O–H, C-H stretching, C≡C, C=C/C=O, C–H, dan P=O dengan dominasi unsur C (~53%) dan O (~48,1%). Karbon aktif TSAC 2321 hasil refluks memiliki luas permukaan terbesar mencapai 49,6795 m²/g. Kajian kinetika adsorpsi multi ion Fe(II)/Cu(II) dengan RHAC dan TSAC mengikuti pemodelan pseudo second order (PSO), sedangkan kajian isoterm adsorpsi multi ion Fe(II)/Cu(II) mengikuti beragam pemodelan seperti Redlich-Peterson, Elovich, dan Jovanovich. Kapasitas adsorpsi terbaik RHAC 232 pada ion Fe(II) dan RHAC 2321 pada ion Cu(II) berturut-turut sebesar 0,3426 mg/g dan 0,4134 mg/g. Karbon aktif TSAC 232 dan 2321 cenderung menjerap ion Cu(II) dengan kapasitas adsorpsi masing-masing sebesar 0,4609 mg/g dan 0,5556 mg/g.Preparation of Activated Carbon from Rice Husk and Teak Sawdust using Reflux Process as Adsorbent for Multi Ion Fe(II)/Cu(II) Solutions. Rice husks and teak wood sawdust are lignocellulosic materials with potential as activated carbon sources. This study aims to determine the effect of the reflux process on the characteristics of RHAC and TSAC as an adsorbent. The rice husk and teak sawdust were carbonized at 400 °C and refluxed using 2 N NaOH solution at 100 °C. The carbon was impregnated using 30% H3PO4 with a carbon: H3PO4 ratio 1:3 (w/w). The RHAC/TSAC was applied to adsorb multi-ions Fe(II)/Cu(II), and its adsorption kinetics and isotherms studies were studied. The results showed that the RHAC and TSAC had O-H, C–H stretching, C≡C, C=C/C=O, C-H, and P=O functional groups with the dominance of C (~53%wt) and O (~48.1%wt) elements. The refluxed TSAC 2321 has the largest surface area of 49.6795 m²/g. The adsorption kinetics study of the Fe(II)/Cu(II) multi-ion using RHAC and TSAC follows the pseudo-second-order (PSO) modeling, while the adsorption isotherm study of the Fe(II)/Cu(II) multi-ion using RHAC and TSAC follows various models such as Redlich-Peterson, Elovich, and Jovanovich. The best adsorption capacity of RHAC 232 on Fe(II) ions and RHAC 2321 on Cu(II) ions is 0.3426 mg/g and 0.4134 mg/g, respectively. The TSAC 232 and 2321 tend to adsorb Fe(II) and Cu(II) ions with an adsorption capacity reaching 0.4609 mg/g and 0.5556 mg/g, respectively.
Sintesis dan Karakterisasi Film Pengemas Aktif dari Kombinasi Kitosan-Alginat dan Asam Sitrat Sulistiyana Sulistiyana; Baiq Amelia Riyandari; Nini Nurkamariati
ALCHEMY Jurnal Penelitian Kimia Vol 20, No 1 (2024): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.20.1.79153.120-129

Abstract

Salah satu permasalahan yang terjadi di bidang pangan adalah penurunan kualitas pangan karena proses oksidasi lipid. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan variasi konsentrasi asam sitrat terhadap karakteristik film Kompleks Polilektrolit (KPE) Kitosan Alginat. Penelitian ini menggunakan metode eksperimen dengan pendekatan kuantitatif. Film KPE pada penelitian ini diperoleh dari penambahan asam sitrat dengan variasi konsentrasi 0 ppm(A0), 5 ppm(A1), 10 ppm(A2) dan 20 ppm(A3) ke dalam larutan kitosan-alginat. Parameter uji karakteristik film meliputi uji ketebalan, kadar air, kelarutan, densitas, transparansi film, FTIR dan aktivitas antioksidan. Hasil uji statistik menunjukkan penambahan asam sitrat dengan variasi konsentrasi berpengaruh signifikan terhadap karakteristik film kitosan alginat. Penambahan asam sitrat mampu meningkatkan ketebalan, densitas, dan transparansi film, namun menurunkan kadar air dan kelarutan film. Film kitosan alginat dengan penambahan asam sitrat memiliki nilai ketebalan dengan kisaran 0,0123-0,0187 mm dan telah memenuhi standar ketebalan edible film menurut Japanese Industrial Standard (JIS). Kadar air film berada pada rentang 11,74-15,85% dan telah memenuhi standar kadar air film sesuai SNI 06-3735-1995. Nilai kelarutan film berada pada rentang 8,33-12,215%, nilai transparansi film berada pada rentang 0,5127-4,9910, sedangkan nilai densitas film berada pada rentang 0,2105-2,0350 g.mL-1. Nilai aktivitas antioksidan tertinggi dimiliki oleh film dengan konsentrasi asam sitrat tertinggi (film A3).Synthesis and Characterization of Active Packaging Film from a Combination of Chitosan Alginate and Citric Acid. One problem in the food sector is a decrease in food quality caused by the lipid oxidation process. This research aims to determine the effect of adding citric acid at different concentration levels to chitosan-alginate polyelectrolyte complex (PEC) films. This research used an experimental method with a quantitative approach. The concentrations of citric acid used in this research were 0 ppm(A0 film), 5 ppm(A1 film), 10 ppm(A2 film), and 20 ppm(A3 film). The physical properties tests of the films included thickness, water content, solubility, density, and transparency. The chemical properties test of the films included FTIR and antioxidant activity. Statistical test results showed that adding citric acid with varying concentrations significantly affected the characteristics of chitosan alginate films. Adding citric acid could increase film thickness, density, and transparency while decreasing film water content and solubility. The characteristics of chitosan alginate film with the addition of citric acid resulted in a film thickness of 0.0123 - 0.0187 mm. The range of the film density was 0.2105 - 2.0350 g.mL-1, while the range of water content was 11.74-15.85%. These values correspond to SNI 06-3735-1995. The value of film solubility was 8.33–12.215%. The transparency of films was 0.5127–4.9910. Antioxidant activity was tested using a DPPH solution, which showed that the highest concentration of citric acid in films had the greatest antioxidant activity.
Removal of Heavy Metals: Pb(II), Ni(II) And Cd(II) By Fe3O4@SiO2-TMPDT Adsorbent Prepared From Rice Husk Ash Sri Hastuti; Tri Martini; Atmanto Heru Wibowo; Dina Fitriana; Wihda Zuhara; Hesti Mutma&#039;inah; Rima Indriyana Putri
ALCHEMY Jurnal Penelitian Kimia Vol 21, No 1 (2025): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.21.1.91934.53-63

Abstract

The adsorption of Pb(II), Ni(II), and Cd(II) metal ions onto Fe3O4@SiO2-TMPDT adsorbent was carried out through batch experiments. In this study, Fe3O4@SiO2-TMPDT adsorbent was synthesized through a sol-gel process using sodium silicate extracted from rice husk ash (Na2SiO3)RHA with the addition of magnetite (Fe3O4) and modifier N1-(3-trimethoxysilylpropyl) diethylenetriamine (TMPDT). The synthesized adsorbent was then characterized by FTIR. The Fe3O4@SiO2-TMPDT adsorbent was prepared with suspension Fe3O4:(Na2SiO3)RHA ratios (v/v) of 1:4, 2:3, and 1:1, and varying the amounts of TMPDT of 1; 2.5 and 5 mL. The optimum pH to perform conditions adsorption for Pb(II) metal ions was determined to be 4, while Ni(II) and Cd(II) were 5. In addition, the adsorption process followed a pseudo-second-order kinetic model, and the adsorption isotherm was consistent with the Langmuir isotherm. The adsorption capacities for Pb(II), Ni(II), and Cd(II) were 11.760 mg/g, 1.864 mg/g, and 1.888 mg/g, respectively.
Cyclic Voltammetry Study of the Influence of Concentration of K3[Fe(CN)6] and Glucose on Glassy Carbon Electrode Adella Fajaretta Gunawan; Arie Hardian; Anceu Murniati
ALCHEMY Jurnal Penelitian Kimia Vol 21, No 1 (2025): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.21.1.87604.43-52

Abstract

Biosensors are cost-effective, user-friendly devices with rapid response, sensitivity, selectivity, and stability. This study investigated the impact of K3[Fe(CN)6] concentration and glucose on glassy carbon electrode (GCE) performance. The cyclic voltammetry method determined the effects of varying K3[Fe(CN)6] and glucose concentrations on GCE. GCE characterization utilized K3[Fe(CN)6] solutions (1 – 5 mM) in 0.2 M KCl and achieved an optimum scan rate of 75 mV/s within -1.5 to 1 V vs. Ag/AgCl. Reversible Fe2+/Fe3+ redox occurred at 1mM (ipa/ipc= 0.99), with the highest reduction peak at 5mM. Glucose tests (1mM to 5mM) in 0.1 M NaOH exhibited an optimal scan rate of 200 mV/s within a potential range of -10 – 10 V at 1 mM (ipa/ipc= 1.01), with the highest oxidation peak at 5 mM. GCE effectively measured concentration effects, with ipa/ipc values close to 1, indicating reversible redox processes at low concentrations. Higher concentrations yielded stronger peak currents due to increased electroactive species.
Synthesis of Acrylated Alkyd Resins from Castor Oil and Their Performance Evaluation in Environmental Implications for Coating Applications Nadia Baqer Hussein; Doaa Jalil Al-Taie
ALCHEMY Jurnal Penelitian Kimia Vol 21, No 1 (2025): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.21.1.96504.162-179

Abstract

This study presents the synthesis of acrylated alkyd resins derived from castor oil for environmentally-friendly coating applications. A novel approach to alkyd resin synthesis was developed and involved free-radical polymerization with acrylic monomers to enhance drying time, chemical resistance, and solubility. The method advantages controlled radical polymerization to optimize the acrylic-to-alkyd ratio and oil length, resulting in improved film properties, including higher crosslink density and faster drying rate compared to traditional methods. The study also focuses on challenges, such as the observed negative impact on certain film characteristics, which include reduced chemical resistance at high levels of acrylic modification. The limitations underscore the importance of balancing acrylic and alkyd phases to achieve optimal performance. Comprehensive physicochemical analyses, which include FTIR and 1HNMR, confirm the formation of the hybrid structure, while performance tests reveal significant advantages over conventional solvent-borne alkyds. This work establishes a foundation for advanced coating binders that combine sustainability with enhanced functionality while recognizing the need for further optimization to mitigate limitations at high modification levels.
Improved Physico-Mechanical Properties and Microstructure of Modified Kenaf Fiber Reinforced Composites Eka Marya Mistar; Muhammad Muhammad
ALCHEMY Jurnal Penelitian Kimia Vol 21, No 1 (2025): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.21.1.92620.64-71

Abstract

This study examined the properties of chemically modified kenaf fiber using propionic anhydride as reinforcement in vinyl ester composites. The composites reinforced by unmodified and modified kenaf fibers were fabricated using 10, 20, 30, 40, and 50% (w/w) via a hand lay-up technique. This study’s characterization included water absorption, thickness swelling, tensile and flexural strengths, and morphological analyses. The optimum physical, mechanical, and morphological properties were observed from the composite with 40% modified kenaf fiber. The optimized composite showed a considerable enhancement in the water absorption, tensile strength, and flexural strength of 1.82%, 54.90 MPa, and 55.85 MPa, respectively. These findings were supported by the fracture morphology after the mechanical test, exhibiting an enhanced interfacial modified kenaf fiber-matrix bonding. The improved characteristics of the composite were ascribed to the impact of the modification process within the fiber-matrix structures. Modified kenaf fiber via propionylation can be applied as a reinforcement material in the vinyl ester matrix.

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