Technological advances in the field of nanomaterials have made several silica processing industries start producing silica nanoparticles so that the search for new sources capable of producing silica has been in great demand. One of the mineral resources that has the potential to be developed is silica (SiO2). Pumice is an amorphous porous volcanic rock consisting of silica. In this study, nanosilica was made from pumice stone by extracting it using NaOH solution at various concentrations of 2.5 M, 2.7 M, 2.9 M, 3.1 M and 3.3 M to observe its effect on the amount and chemical composition of nanosilica powder. resulting, the nanosilica phase formed and the size of the nanosilica. This silica extraction is made by sol-gel method using reflux. Silica gel formation was carried out using 5M H2SO4 and the refining process of silica powder using 1.25 M HCl then calcined at 800oC for 6 hours and characterized by XRF, XRD, TEM and FTIR. The results obtained in this study indicate the effect of NaOH concentration on the amount of powder produced, which increases with the increase in the concentration of NaOH used. The SiO2 composition of all samples showed optimum results in samples with a concentration of 2.7 M NaOH, namely 97.1% which also had SiO-Si and Si-OH bonds, had an amorphous phase and the mean particle size was (11.9 ± 2). , 6) nm.

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A study has been conducted on the extract concentration effect of Maja Peel as an inhibitor of low carbon API 5L in corrosive medium of NaCl 3% and H2SO4 3%. The soaking process of low carbon API 5L was done for 35 days with variation of addition inhibitor concentrations at 0%, 0,4%, 0,5%, 0,6%, 0,7%, and 0,8%. The testing of Corrosion rate is done by weight loss method. The results showed that the highest corrosive rate in corrosive medium of NaCl 3% and H2SO4 3% was at 0% which is inhibitor concentration, 0,06 x 10 4 mm/y and 16,55 x 10 4 mm/yconcentration. Meanwhile, the lowest corrosion rate at 0.8% inhibitor concentration for corrosive medium ofNaCl 3% and 0.5%for H2SO43% corrosive medium. Hence, the greatest effectiveness of corrosion occurs at the concentration of 0.8% in a corrosive medium of NaCl 3% with effectiveness of 85,71% and 0.5% in corrosive medium of H2SO4 3% with the effectiveness of 79.35%. The characterization result of X-Ray Diffraction (XRD) shows that the phase formed is pure Fe. Characterization of Scanning Electron Microscopy (SEM) showed uneven clusters and smaller sizes, holes and cracks also with less than 0.8% inhibitors for corrosive medium of NaCl 3% and 0.5% for corrosive medium of H2SO43% compared with 0% inhibitor of maja peel extract on corrosive medium ofNaCl 3% and H2SO4 3%. Characterization of Energy Dispersive Spectroscopy (EDS) in samples with corrosive medium of H2SO43% obtained the element S (Sulfate).Keywords: low carbon API 5L, the extract of maja peel, corrosion inhibitor, NaCl, and H2SO4.Abstrak. Telah dilakukan penelitian mengenai pengaruh konsentrasi ekstrak kulit buah maja sebagai inhibitor pada baja karbon API 5L dalam medium korosif NaCl 3% dan H2SO4 3%. Perendaman baja karbon API 5L dilakukan selama 35 hari dengan variasi konsentrasi penambahan inhibitor ekstrak kulit buah maja 0%, 0,4%, 0,5%, 0,6%, 0,7%, dan 0,8%. Pengujian laju korosi dilakukan dengan metode kehilangan berat. Hasil penelitian menunjukkan laju korosi terbesar pada medium korosif NaCl 3% dan H2SO4 3%adalah pada konsentrasi inhibitor 0% , yaitu sebesar 0,06 x 10 4 mm/y dan 16,55 x 10 4 mm/y. Sementara, laju korosi terendah yaitu pada konsentrasi inhibitor 0,8% untuk medium korosif NaCl 3% dan 0,5% untuk medium korosif H2SO4 3%. Sehingga efektivitas korosi yang paling besar terjadi pada konsentrasi 0,8% pada medium korosif NaCl 3% dengan efektivitas sebesar85,71%, dan 0,5% pada medium korosif H2SO4 3% dengan efektivitas sebesar 79,35%. Hasil karakterisasi X-RayDiffraction (XRD) memperlihatkan bahwa fasa yang terbentuk adalah Fe murni. Karakterisasi Scanning Electron Microscopy (SEM) memperlihatkan cluster (gumpulan) tidak merata dan ukuran lebih kecil, lubang (hole) dan retakan (crack) juga lebih sedikit dengan inhibitor 0,8% untuk medium korosif NaCl 3% dan 0,5% untuk medium korosif H2SO4 3% dibandingkan dengan inhibitor 0% ekstrak kulit buah maja pada medium korosif NaCl 3% dan H2SO4 3%. Karakterisasi Energy Dispersive Spectroscopy (EDS) pada sampel dengan medium korosif H2SO4 3% didapatkan uns...

Research on the formation of TiO2 nanofiber has been carried out with PVP variations of 1.1; 1,2; 1.3; 1.4 and 1.5 grams using electrospinning. This study aims to determine the effect of PVP variation on the viscosity and morphology of TiO2 nanofibers and to determine the crystal structure of the fibers. Synthesis of TiO2 was carried out using the sol-gel method. TTIP is used as a precursor, ethanol as a solvent, acetic acid as a catalyst and PVP as a fiber-forming polymer. The results of the viscosity measurement show that the amount of PVP used in the sample is directly proportional to the level of solution viscosity. Based on the results of SEM characterization, it showed relatively uniform nanofiber morphology with fiber diameter ranging from 94 nm - 735 µm. The results of TEM characterization showed that the size of TiO2 nanofiber particles ranged from 7-15 nm. The results of XRD analysis showed that the crystal structures formed at a calcination temperature of 450 oC were the anatase and rutile phases.

Penelitian tentang pengaruh variasi penambahan abu ampas tebu dan serat ampas tebu terhadap sifat fisis dan mekanis pada mortar telah dilakukan. Bahan-bahan yang digunakan dalam penelitian ini antara lain abu ampas tebu, serat ampas tebu, semen portland, CaCl dan air. Abu ampas tebu diperoleh dari pembakaran ampas tebu pada suhu 700 ˚C selama 2 jam. Serat ampas tebu diperoleh dari pencacahan ampas tebu menggunakan mesin disk mill dengan ayakan berukuran 5 mm. Perbandingan semen, abu ampas tebu dan serat ampas tebu yang digunakan yaitu sampel A (90%:0%:10%), sampel B (85%:5%:10%) dan sampel C (80%:10%:10%), dengan penambahan CaCl sebesar 5% dari massa total dan 250 ml air. Pengujian yang dilakukan yaitu uji fisis (daya serap air dan kerapatan) dan uji mekanis (kuat tekan, kuat lentur dan kuat tarik belah) serta karakterisasi scanning electron microscope-energy dispersive x-ray spectroscopy (SEM-EDS). Mortar sampel A masuk dalam kategori mortar tipe S dengan kuat tekan sebesar 132,28 kg/cm2, mortar sampel B masuk dalam kategori mortar tipe M dengan kuat tekan sebesar 176,16 kg/cm2 dan mortar sampel C masuk dalam kategori mortar tipe S dengan kuat tekan sebesar 170,68 kg/cm2, secara keseluruhan sampel C memiliki nilai yang lebih tinggi baik secara fisis maupun mekanisnya, mikrostruktur sampel C lebih baik dibandingkan sampel A dan B karena memiliki butiran yang lebih kecil serta terdapat banyak gumpalan yang menyebabkan ukuran pori mengecil sehingga kerapatannya meningkat, penambahan abu ampas tebu meningkatkan jumlah unsur oksigen yang dapat menambah kekuatan mekanis mortar.