Effect of the addition of inhibitors of kirinyuh leaf (Chromolaena Odorata) in methanol extract on corrosion rate of ASTM 36 steel

Kirinyuh leaves (Chromolaena Odorata) contain alkaloids, saponins, flavonoids, phenols, and tannins with the potential as a natural inhibitor that can be used to inhibit the rate of corrosion. Kirinyuh leaf extract inhibitors were added at various concentrations of 100 ppm, 200 ppm, 300 ppm, 400 ppm, and 500 ppm, which were sprayed onto the sample surface before being soaked for seven days. Calculation of the corrosion rate using the method of weight loss (weight loss). The results showed that kirinyuh leaf extract effectively inhibited the corrosion rate. The smallest corrosion rate value was found in the sample with the addition of 400 ppm inhibitor concentration, which was 2.053 ppm. Meanwhile, an efficiency inhibitor was also found in the same concentration of inhibitor that is equal to 87%

Pengaruh Ukuran Partikel, Persen Padatan, dan pH pada Proses Flotasi Terhadap Perolehan Kembali Tembaga

Flotasi merupakan proses ekstraksi logam berdasarkan perbedaan tegangan permukaan dari mineral di dalam air dengan cara mengapungkan mineral ke permukaan. Faktor yang mempengaruhi nilai perolehan kembali Tembaga antara lain ditentukan oleh ukuran partikel, jumlah persen padatan dan kondisi larutan. Pada penelitian ini akan dilakukan pengamatan terhadap perolehan kembali mineral tembaga dengan melakukan variasi ukuran partikel, variasi persen padatan pada jumlah 33%, 42% dan 47% dan variasi pH larutan pada kondisi basa yaitu pH 10, 10.3 dan 10.6. Pengecilan ukuran partikel dilakukan dengan proses Grinding sampai mendapatkan ukuran + 212 mikron. Selanjutnya, pH larutan dikontrol dengan penambahan kapur. Analisis perolehan kembali mineral tembaga secara kuantittatif dilakukan dengan karakterisasi AAS. Hasil penelitian menunjukkan bahwa ukuran partikel yang optimum didapat pada pada variasi 3% +212 mikron dengan nilai 95.12%. Sedangkan, jumlah persen padatan 42% memberikan nilai tertinggi yaitu 95.12%. Selanjutnya, diperoleh pH terbaik untuk memperoleh tembaga yang optimum yaitu pada pH 10.6 sebesar 95.12

STUDI TEORITIS MATERIAL KATODA BATERAI ION LITIUM LiFePO4 BERDASARKAN KALKULASI TEORI FUNGSIONAL KERAPATAN

To fully utilize the intermittent renewable energy resources, energy storage applications such as lithium-ion batteries (LIBs) become very critical. Among LIBs components, cathode part is very important. LiFePO4 material is among the cathode material which has gained significant attention owing to its environmentally friendly and low-cost features compared to Co- or Ni-based cathodes. In this study, we present a theoretical investigation of LiFePO4 material using density functional theory calculations. We optimized LiFePO4 as well as FePO4 structures. Li ion intercalation potential into the structure was also calculated. In addition, the electronic structure of the material was also studied. The present study may provide an insight for further investigation of cathode materials for LIB applications.Dalam memanfaatkan energi baru dan terbarukan yang bersifat tidak berkesinambungan, aplikasi penyimpanan energi seperti baterai ion litium (BIL) menjadi sangat penting.  Di antara komponen BIL yang sangat penting adalah katoda. Material LiFePO4 merupakan salah satu katoda untuk BIL yang menarik perhatian sangat besar dikarenakan sifatnya yang relatif ramah lingkungan serta relatif tidak mahal dibandingan dengan katoda lain berbahan Co atau Ni. Pada penelitian ini, kami menyajikan hasil studi teoritis material LiFePO4 menggunakan kalkulasi teori fungsional kerapatan. Kami melakukan optimasi struktur LiFePO4 beserta FePO4. Kemudian, nilai potensial interkalasi ion Li ke dalam struktur juga diprediksi. Selain itu, struktur elektronik material tersebut juga dipelajari. Studi ini dapat menjadi bahan acuan yang dapat digunakan sebagai teknik dalam mempelajari material untuk aplikasi katoda pada BIL

Preparation of synthesis nanoparticles Fe3O4 based on iron sand Sumbawa

Iron sand generally contains minerals such as ilmenite, magnetite, and hematite. Based on the results of previous tests, the main composition of iron sand in Rhee, Sumbawa regency, is magnetite. One method to increase the Fe content in iron sand is by pre-treatment with NaOH. NaOH is also used to precipitate heavy metals in a mineral. In this study, three variations were carried out with the ratio of NaOH: iron sand, namely: 1: 4, 2: 4, and 3: 4 at a temperature of 300 C. Furthermore, the calcination results were followed by the synthesis of Fe3O4 nanoparticles using the coprecipitation method. The results of the XRF characterization showed an increase in Fe levels after being processed by the alkalization treatment. The highest concentration was obtained in 1:4, with a Fe percentage of 91.1%. The results of the XRD characterization showed that the synthesis of Fe3O4 was successfully carried out with single phase Fe3O4 amlording to the data reference 96-9005839 forms and the space group F d -3 m. Crystal size analysis Using the Debey-Scherrer equation, the respective sizes were 12.7 nm, 8.71 nm, and 9.76 nm, respectively

Effect of the addition of inhibitors of kirinyuh leaf (Chromolaena Odorata) in methanol extract on corrosion rate of ASTM 36 steel

Kirinyuh leaves (Chromolaena Odorata) contain alkaloids, saponins, flavonoids, phenols, and tannins with the potential as a natural inhibitor that can be used to inhibit the rate of corrosion. Kirinyuh leaf extract inhibitors were added at various concentrations of 100 ppm, 200 ppm, 300 ppm, 400 ppm, and 500 ppm, which were sprayed onto the sample surface before being soaked for seven days. Calculation of the corrosion rate using the method of weight loss (weight loss). The results showed that kirinyuh leaf extract effectively inhibited the corrosion rate. The smallest corrosion rate value was found in the sample with the addition of 400 ppm inhibitor concentration, which was 2.053 ppm. Meanwhile, an efficiency inhibitor was also found in the same concentration of inhibitor that is equal to 87%

Physical and Mechanical Properties of Fiber Board from Corn Husk Fiber

Using agricultural waste materials, namely corn husk fiber (CHF), to reduce agricultural waste and recycle corn husk waste into sustainable engineering materials is relatively significant due to the decreasing number of woods. This study aims to analyze the effect of the volume fraction of CHF with polyester (PE) on the physical and mechanical strength of fiberboard composites with variations in volume fraction of 25% fiber : 75% PE, 50% fiber : 50% PE, and 75% fiber : 25% PE. Composites are made by the hand layup method. Fibers were pretreated by immersing 5% NaOH for 2 hours. The results of testing the physical properties of the highest density composite board at a volume fraction of 25% fiber : 75% PE of 0.85 g/cm³ and the lowest moisture absorption value was at 0.49%. The results of the mechanical board test in the form of the modulus of elasticity (MOE) test got the highest test value at the fiber volume fraction 25% fiber : 75% PE, which was 1179.2 MPa as well as the highest modulus of rupture (MOR) test value was found in the volume fraction 25% fiber: 75% PE that is equal to 9.4 MPa. Based on this result research, the average strength of the mechanical properties increases with the increase in the number of matrices. That indicates a reasonably good bond between the fiber and the matrix. The results of the water content test also increased as the density value increased.DOI: 10.17977/um024v7i22022p13

Preparation of synthesis nanoparticles Fe3O4 based on iron sand Sumbawa

Iron sand generally contains minerals such as ilmenite, magnetite, and hematite. Based on the results of previous tests, the main composition of iron sand in Rhee, Sumbawa regency, is magnetite. One method to increase the Fe content in iron sand is by pre-treatment with NaOH. NaOH is also used to precipitate heavy metals in a mineral. In this study, three variations were carried out with the ratio of NaOH: iron sand, namely: 1: 4, 2: 4, and 3: 4 at a temperature of 300 C. Furthermore, the calcination results were followed by the synthesis of Fe3O4 nanoparticles using the coprecipitation method. The results of the XRF characterization showed an increase in Fe levels after being processed by the alkalization treatment. The highest concentration was obtained in 1:4, with a Fe percentage of 91.1%. The results of the XRD characterization showed that the synthesis of Fe3O4 was successfully carried out with single phase Fe3O4 amlording to the data reference 96-9005839 forms and the space group F d -3 m. Crystal size analysis Using the Debey-Scherrer equation, the respective sizes were 12.7 nm, 8.71 nm, and 9.76 nm, respectively

Pelindian Bijih Emas Menggunakan Natrium Tisulfat 1 M dan Hidrogen Peroksida 30% : Pelindian Bijih Emas Menggunakan Natrium Tisulfat 1 M dan Hidrogen Peroksida 30%

salah satu mineral yang memiliki nilai ekonomis yang tinggi sehingga menjadikan mineral ini seringdieksploitasi secara besar-besaran khususnya di Kabupaten Sumbawa Barat adalah mineral logam emas (Au). Pada umunya proses pelindian emas menggunakan metode sianidasi dan amalgamasi, akan tetapi kedua metodeini memiliki tingkat toksisitas yang tinggi terhada lingkungan. Salah satu metode alternatif pelindian bijih emasmenggunakan natrium tiosulfat. Penggunaan natrium tiosulfat dinilai sangat efektif, dikarenakan perolehan emasyang tinggi, resiko terhadap lingkuingan yang rendah, pelarutan emas lebih cepat dibandingkan dengan sianidadan reagen yang digunakan juga cukup ekonomis. Pelindian dilakukan menggunakan bijih emas ukuran 200mesh yang di ambil di Desa Pekirum dengan natrium tiosulfat sebagai reagen dan hidrogen peroksida sebagaioksidator. Pada penelitian ini, proses pelindian dilakukan dengan menggunakan konsentrasi natrium tiosulfat 1M, konsentrasi H?O? 30%, waktu pelindian selama 6 jam dan pada temperatur 60°C. Hasil karakterisasimenggunakan AAS menunjukkan bahwa persentase perolehan emas menggunakan natrium tiosulfat dan H?O? sebesar 49,42%.One of the minerals that has high economic value, so that this mineral is often exploited on a large scale, especially in West Sumbawa Regency, is the metallic gold mineral (Au). In general, the gold leaching processuses cyanidation and amalgamation methods, but these two methods have a high degree of toxicity to theenvironment. One alternative method of leaching gold ore is using sodium thiosulfate. The use of sodiumthiosulphate is considered very ef ective, due to high gold recovery, low risk to the environment, faster dissolution of gold compared to cyanide and the reagent used is also quite economical. Leaching was carriedout using 200 mesh size of gold ore taken at Pekirum Village with sodium thiosulphate as a reagent andhydrogen peroxide as an oxidizing agent. In this study, the leaching process was carried out using aconcentration of 1 M sodium thiosulphate, 30% H?O? concentration, 6 hours of leaching time and a temperatureof 60°C. The characterization results using AAS showed that the percentage of gold recovery using sodiumthiosulfate and H?O

PELINDIAN BIJIH EMAS MENGGUNAKAN TIOSULFAT DENGAN PERBANDINGAN RASIO PADAT-CAIR 1:20 PADA TEMPERATUR 90? PELINDIAN BIJIH EMAS MENGGUNAKAN TIOSULFAT DENGAN PERBANDINGAN RASIO PADAT-CAIR 1:20 PADA TEMPERATUR 90?

Leaching of gold ore using sodium thiosulfate reagent has been successfully carried out. The gold ore used in this study is gold ore from the Pakirum region, West Sumbawa District, West Nusa Tenggara Province. The use of thiosulfate reagent in this gold separation process is due to its very low toxicity level, can extract various types of ores, and provides a high recovery rate and very fast kinetics compared to cyanide. In this study, the leaching process was carried out using a solid-to-liquid ratio of 1:20 at 90? with a particle size of 200 mesh, using thiosulfate reagent concentration of 0.6M with the help of 30% H?O? oxidizing agent. Gold content testing in this study was carried out using the AAS (Atomic Absobtion Spektrophotometer) test, because AAS has a fairly good level of accuracy and precision. The result of this study indicate that the highest gold recovery is 98.27% in leaching time of 6 hours. While the lowest gold yield was 65.51% at the 2 hours leaching time.Pelindian emas dengan menggunakan reagen Natrium tiosulfat telah berhasil dilakukan. Biji emas yang digunakan pada penelitian ini adalah bijih emas dari wilayah Pakirum, Kabupaten Sumbawa Barat, Provinsi Nusa Tenggara Barat. Pelnggunaan relageln tilolsulfat pada prolsels pelmilsahan elmas ini karena tilngkat tolksisitas yang sangat relndah, dapat melngekstrak biljilh delngan belrbagail tilpel, dan melmbelrilkan tilngkat relcolvelry yang tilnggil selrta kilneltilka yang sangat celpat dilbandilngkan silanilda. Pada penelitian ini, proses pelindian dilakukan dengan menggunakan rasio padat-cair 1 : 20 pada suhu 90? dengan ukuran partikel 200 mesh, menggunakan reagen tiosulfat konsentrasi 0.6M, dengan bantuan oksidator H?O? 30%. Pengujian kandungan kadar emas pada penelitian ini dilakukan dengan menggunakan pengujian AAS (Atomic Absobtion Spektrophotometer), karena AAS memiliki tingkat keakuratan dan presisi yang cukup baik. Hasil pada penelitian ini menunjukkan bahwa perolehan emas tertinggi yaitu sebesar 98.27% dalam waktu pelindian selama 6 jam. Sedangkan hasil perolehan emas terendah yaitu sebesar 65.51% pada waktupelindian ke 2 jam