Proses sintesis silika (SiO2) berbasis bahan alam telah dilakukan dengan metode kopresipitasi menggunakan NaOH. Bahan dasar pasir alam yang digunakan berasal dari pasir pantai Bancar, Tuban, Jawa Timur, Indonesia. Penelitian ini bertujuan untuk mengetahui SiO2 berbasis bahan alam menggunakan uji XRF dan XRD. Penelitian dilakukan dengan perlakuan yang berbeda. Kajian awal dari analisis X-ray Fluorescence (XRF) menunjukkan bahwa pasir alam pantai Bancar yang digunakan mengandung unsur Si 81,7 wt%. Berdasarkan pola X-ray Diffraction (XRD) mengindikasikan bahwa SiO2 hasil sintesis yang terbentuk adalah silika kuarsa dengan background amorf. Kandungan SiO2 yang didapatkan menunjukkan kesesuaian yang baik dilakukan dengan analisis menggunakan software Rietica diperoleh GoF < 4% dan menggunakan software MAUD diperoleh estimasi ukuran kristal silika hasil kopresipitasi ∼52,7 ± 21,9 nm. Diharapkan kandungan SiO2 yang diperoleh memiliki potensi yang menjanjikan sebagai aplikasi material teknologi tinggi.

Volume magnetic susceptibility measurements have been widely used in numerous studies related to river sediment characterization. A study of the transport distance effect toward the frequency-dependent volume magnetic susceptibility is needed to identify the superparamagnetic grain behavior in river sediments. The purpose of this study is to identify the presence of superparamagnetic grains and to obtain the relation between transport distances and frequency-dependent volume magnetic susceptibility in river sediments. The sediment samples were taken and measured by using the Bartington MS2B Susceptibilitymeter at two different frequencies of 470 Hz and 4700 Hz. The measurement results show that the sediment transport distance is directly proportional to the frequency-dependent volume magnetic susceptibility. Superparamagnetic grain content is identified to tend to be higher as the distance of sediment transport increases.

In this work, hydrophobic of modified SiO2 coating for self cleaning material were prepared by dip-coating methods and solvothermal manual. SiO2 was successfully prepared from silica sand by purified followed sol-gel methods. Tetraetoxysilane (TEOS) and Hexamethyldisilanze (HMDS) were used as surface chemical modification agents with varied mass of SiO2, which were 1, 2, 3, and 4 g. X-ray fluorescence spectrometer (XRF) , X-ray powder diffraction (XRD), Particle size analyzer (PSA), Ultraviolet–visible spectrophotometer (UV-Vis), and Water contact angle (WCA) were employed to investigate the element composition, crystal structure, size of particles, transparency, and hydrophobicity of coating. The results indicated that modified SiO2 coatings has hydrophobic feature as self cleaning material (WCA > 90˚) for indium tin oxide (ITO) glass.

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Batteries and supercapacitors are one of the energy storage devices that had been used for a practical application most electronic devices such as mobile phone. The development of these energy storage devices is faced by the poor performance of (the) electrode. Electrode commonly used for batteries and supercapacitors is derived from nonrenewable carbon resources such as graphite. However, the availability of this material is becoming a long-term problem for the development of batteries and supercapacitors. Biomass from (the) waste plant as a green source for battery electrode is one of alternative carbon which has great potential, due to the low price, easy to process and has high stability. This paper reports the study of the biomass conversion into carbon electrode material having high electrical conductivity or low electrical resistivity using carbonization and pyrolysis process. The process involved FeCl3 as an activating agent to reduce the electrical resistivity of the material as low as possible. The research was studying the effect of biomass sources and the processing method on the electrical resistivity of the electrode produced. The biomasses used in the study were corncob, water hyacinth, rice straw, and coconut husk. The material is the waste plant which is available in abundant. The morphological analysis of the carbon surface was conducted using Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX). The lowest electrical resistivity was produced from corncob material through the carbonization process at 300°C for 2 h, activated by 4 M FeCl3 solution and followed by pyrolysis process at 800°C for 6 h. The FeCl3 is suspected responsible for the decreasing of the carbon resistivity or increasing the electrical conductivity produced, this correlates with the increase of the surface area of the material. The lowest electrical resistivity (highest electrical conductivity) produced from corncob has a value of 1 Ω with the surface area of 601 m2/g. This is considered better than graphite in term of electrical resistivity in which graphite has electrical resistivity between 10 - 30 Ω. The result of SEM images shows that the carbon surface activated by FeCl3 has more pores compared to the carbon without activation.