Unesa Journal of Chemistry https://ejournal.unesa.ac.id/index.php/unesa-journal-of-chemistry <p><em>UNESA Journal of Chemistry</em>&nbsp;is published &nbsp;online 3 times a year (January, May and September) and covering all aspect of Chemistry, including :</p> <p>1. Analytical chemistry;</p> <p>2. Physical chemistry;</p> <p>3. Organic chemistry;</p> <p>4. Inorganic chemistry; and</p> <p>5. Biochemistry.</p> <p>The journal publishes original research papers and review articles. The paper published in this journal implies that the work described has not been, and will not be published elsewhere, except in abstract, as part of a lecture, review or academic thesis.</p> Department of Chemistry, Faculty of Mathematics and Natural Sciences, Surabaya State University, located at Jl Ketintang, Surabaya, East Java, Indonesia en-US Unesa Journal of Chemistry 2252-8180 Sintesis Nanopartikel Au-SiO2 Menggunakan Natrium Silikat dari Abu Ampas Tebu (AAT) https://ejournal.unesa.ac.id/index.php/unesa-journal-of-chemistry/article/view/49245 <p><em>Synthesis of Au-SiO<sub>2</sub> has been carried out using sodium silicate solution from bagasse ash (AAT) as the main source of silica. The purpose of this study was to determine the mole ratio of Au:Si in the relatively stable Au-SiO<sub>2</sub> nanoparticles<sub>,</sub> which could be observed from the maximum wavelength and the determination of full width half maximum (FWHM). This type of research is experimental research. This research went through stages, namely synthesis of sodium silicate from bagasse ash, synthesis of Au-SiO<sub>2</sub> and their characterization. The parameters studied were variations in the Au:Si mole ratio (1:19, 1:39 and 1:76), identifying the functional group Au-SiO<sub>2, </sub>determining the maximum wavelength and determining the stability of Au-SiO<sub>2</sub>. The identification of the Au-SiO<sub>2</sub> was carried out using the FTIR instrument and the maximum wavelength was determined using a UV-VIS spectrophotometer. The results obtained are clear liquid Au-SiO<sub>2</sub>, dark red at a ratio of 1:19, pink at a ratio of 1:38 and 1:76. </em><em>The results of identification with FTIR showed that the Au-SiO<sub>2</sub> nanoparticles contained N-H and C-H groups at wave numbers 1566,77 cm<sup>-1</sup> and 2923.02 cm<sup>-1</sup>, siloxane (Si-O-Si) and silanol (Si-OH) groups at wave numbers 1027.24 cm<sup>-1 </sup>and 902,12 cm<sup>-1</sup>.</em> <em>The results of measurements with a UV-VIS spectrophotometer show that Au-SiO<sub>2</sub> nanoparticles are relatively stable at a ratio of 1:76 with a maximum absorption wavelength in the range of 523-523.5 nm, it can be said that silica was able to maintain the stability of Au nanoparticles in storage for 8 days.</em></p> <p><strong><em>Key words: </em></strong><em>nanoparticle Au, silica, bagasse</em></p> Nur Aini Amaria Amaria ##submission.copyrightStatement## 2023-01-31 2023-01-31 11 3 143 152 Rice Husk Ash Characterization Using XRD https://ejournal.unesa.ac.id/index.php/unesa-journal-of-chemistry/article/view/49971 <p><em>Rice husk ash is a material that mostly contains silica (SiO<sub>2</sub>). Silica can be used as a raw material for various industries. This research is an experimental study, covering the synthesis of rice husk ash with various calcination temperatures, namely 800 <sup>o</sup>C, 900 <sup>o</sup>C, and 1000 <sup>o</sup>C. The purpose of this study was to identify the type of solid and crystalline phases of RHA so that the results of this study could be used as a basis for further research on the use of RHA. &nbsp;The results of the synthesis produced four types of samples, namely samples calcined at a temperature of 800 <sup>o</sup>C (coded S-800), calcined at 900 <sup>o</sup>C was gray (S-900 A), calcined at 900 <sup>o</sup>C was white (S-900 P), and samples were calcined at a temperature of 1000 <sup>o</sup>C (S-1000). Characterization using X-Ray Diffraction (XRD) showed that all samples included crystalline solids with the tridymite crystal phase and cristobalite were detected in samples S-800,</em> <em>S-900 P, S-900 A, and S-1000. Cristobalite and tridymite are silica mineral polymorphs with the same chemical formula as quartz, SiO<sub>2</sub>, but have different crystal structures. The percentage of crystallinity of the sample was calculated by comparing the sample which has the highest peak intensity (S-1000). The crystallinity results for S-1000, S-900 P, and S-900 A were 100%, 96%, 79%, and 32%. The lower the calcination temperature, the smaller the percentage of crystallinity.</em></p> <p>&nbsp;</p> <p><strong><em>Keywords: rice husk ash, calcined, silica, XRD, crystalline solid</em></strong></p> samik samik Nita Kusumawati Maria Monica Sianita Dina Kartika Maharani Amalia Putri Purnamasari Mukhlash Imaduddin M Iqbal Al Ghifari ##submission.copyrightStatement## 2023-01-31 2023-01-31 11 3 153 159 Pengaruh Variasi Penimbangan Terhadap Akurasi Penentuan Bilangan Asam Pada Alkyd Resin https://ejournal.unesa.ac.id/index.php/unesa-journal-of-chemistry/article/view/49220 <p>-</p> <p><em>Alkyd resin is a modified polyester with the addition of fatty acids and other components. Alkyds are derived from polyols and organic acids including dicarboxylic acids or anhydrous carboxylic acids and triglyceride oils. The quality of an alkyd resin is determined based on its parameters including solid content, viscosity, acid number, color and clarity. High acid numbers can cause the paint to turn yellow easily, therefore accuracy is needed in analyzing acid numbers. To determine the acid number is done by acidimetric titration method. Products A, B, and C were weighed respectively: 0.5g, 2g, 4g, 6g, 8g, 10g, 12g, 14g, into a 300 ml erlenmeyer which already contained 100 ml of solvent. Enter the magnetic stirrer and stir until completely dissolved over the electric heater. Add 2 drops of 1% phenolphthalein indicator into the Erlenmeyer. Pour the 0.2 alcoholic KOH solution into a 50 ml burette. The titration was carried out until the solution changed from colorless to pink. Record the volume obtained (ml). From the research conducted, the smaller the sample being weighed, the larger the deviation from the analysis of the acid number from the theoretical weighing sample (10 grams). Based on the % accuracy allowed is 3%, the weighing variable that can be tolerated is 8–14 grams. Weighing samples less than 8 grams or above 14 grams will produce acid numbers which have very large deviations.</em></p> <p><em>&nbsp;</em></p> <p><strong><em>Key words: Alkyd resin, Acid number, KOH solution, Titration</em></strong></p> Firman Adji Nur Hidayat I Gusti Made Sanjaya ##submission.copyrightStatement## 2023-01-31 2023-01-31 11 3 160 164 REVIEW ARTICLE: UTILIZATION OF ACTIVATED NATURAL ZEOLITE CATALYST IN BIODIESEL SYNTHESIS WITH ESTERIFICATION AND TRANSESTERIFICATION METHOD https://ejournal.unesa.ac.id/index.php/unesa-journal-of-chemistry/article/view/47056 <p><em>The depletion of petroleum fuels can become a problem if not addressed quickly. This can lead to scarcity and an increase in the price of fuel oil. Alternative energy has begun to be developed as a solution to this problem, one of which is biodiesel. Biodiesel synthesis has the main ingredient&nbsp; in the form of oils such as palm oil, used cooking oil, rubber seed oil, crude palm oil, and others. The biodiesel synthesis reaction is a transesterification reaction that tends to be slow and long, so a catalyst is needed so that the reaction can run quickly. There are two catalysts that can be used, namely homogeneous catalysts and heterogeneous catalysts. The use of heterogeneous catalysts is easier because at the end of the reaction they can be separated easily. One of the heterogeneous biodiesel catalysts that can be used is natural zeolite catalyst. The use of natural zeolite catalysts has many advantages such as its relatively cheap price, abundant abundance in nature, and environmental friendliness. Utilization of natural zeolite as a biodiesel catalyst requires the activation of natural zeolite which can be carried out with acid or alkaline solutions. Therefore, in this review article, we discuss the % yield of biodiesel with the help of natural zeolite catalysts which are activated by acid or base</em><em> from ten articles</em><em>. The highest % biodiesel yield was obtained at 100% in the production of biodiesel from used cooking oil with an acid-activated Wonosari natural zeolite catalyst in the form of 6M HCl in an esterification reaction of 2% by weight of oil. Then proceed with the transesterification reaction with KOH as a base catalyst at a temperature of 60℃ with a molar ratio of oil and methanol 1:6 for 1 hour, </em><em>and </em><em>stirring speed of 1200 rpm.</em> <em>&nbsp;Based on the results of this review article, natural zeolite that has been activated by acid or base can be used as a catalyst in biodiesel synthesis using the transesterification </em><em>and esterification </em><em>method.</em></p> <p>&nbsp;</p> <p><strong><em>Key words: </em></strong><strong><em>Biodiesel, Biodiesel Catalyst, Natural Zeolite</em></strong></p> Siti Novita Sari Ulfa Samik Samik ##submission.copyrightStatement## 2023-01-31 2023-01-31 11 3 165 181 THE EFFECT OF NANOSILVER ADDITION TOWARD ANTIOXIDANT ACTIVITY OF NANOPLATINUM ON REDUCTION FREE RADICALS https://ejournal.unesa.ac.id/index.php/unesa-journal-of-chemistry/article/view/37050 <p><em>Manusia secara alami mengalami penurunan fungsi tubuh yang mengakibatkan pemusnahan radikal bebas tidak bekerja secara maksimal. Stress oksidatif yang disebabkan oleh radikal dapat berpengaruh pada beberapa penyakit degeneratif seperti penuaan dini, kanker, dan penyakit jantung coroner. Sebagai upaya dilakukan penelitian yang bert</em><em>ujuan untuk menganalisis dan membahas pengaruh nanosilver terhadap aktivitas antioksidan nanoplatina dalam meredam radikal bebas pada berbagai variasi waktu, serta untuk menganalisis dan membahas konsentrasi nanosilver terbaik yang mendukung aktivitas antioksidan nanoplatina.</em><em> Konsentrasi yang digunakan nanoplatina 20 ppm dan Nanosilver 5 sampai 25 ppm.</em> <em>Menurut penelitian sebelumnya, untuk mengetahui aktivitas antioksidan menggunakan spektrofotometer UV-Vis sebagai alat untuk mengkarakterisasi nanopartikel platina dan metode DPPH untuk menguji aktivitas peredaman radikal bebas karena berpotensi sebagai antioksidan. Hasil penelitian menunjukkan bahwa </em><em>penambahan nanosilver dengan konsentrasi 5, 10, 15, 20 dan 25 ppm memberikan pengaruh yang signifikan terhadap aktivitas antioksidan dari nanoplatina.</em><em> Hasil persen peredaman rata-rata gabungan nanosilver 20 ppm dengan variasi kosentrasi nanoplatina 5, 10, 15, 20, dan 25 ppm masing-masing adalah 75,90 %; 82,90 %; 86,61 %; 87,95 %; dan 85,19%. Pengaruh penambahan nanoplatinum terhadap aktivitas antioksidan nanosilver memiliki kesinergisan karena adanya peningkatan hasil persen peredaman dari setiap peningkatan konsentrasi dengan hasil optimum pada penambahan nanoplatina 20 ppm dengan hasil persen peredaman 87,95% [Hesti, Nita. (2017)].</em></p> <p><em>&nbsp;</em></p> <p><em>Kata Kunci : Nanosilver, Nanoplatina, Aktivitas antioksidan, DPPH</em></p> della bonita anggia putri Titik Taufikurrohmah ##submission.copyrightStatement## 2023-01-31 2023-01-31 11 3 182 191