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Journal : Natural B

The effectiveness study of SnCl2.2H2O masking on the formation of QCM profile using wet etching technique with KOH solution Tri Andi Rusly; D.J. Djoko H. Santjojo; Setyawan P. Sakti; Masruroh Masruroh
Natural B, Journal of Health and Environmental Sciences Vol 4, No 2 (2017)
Publisher : Natural B, Journal of Health and Environmental Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (364.371 KB) | DOI: 10.21776/ub.natural-b.2017.004.02.5

Abstract

SnCl2.2H2O  has been successfully utilized to produce isotropic profile on the surface of a SiO2 crystall by a wet etching procces. The etching process was carried out by using a 40% KOH solution. In this research, the wet etching method is carried out by optimizing the etch time which was varied for 0,5 hour, 1 hour, 1,5 hour.  The profile was determined by applying a SnCl2.2H2O  on the surface of a QCM. The mask was applied by using a spray coating technique. The SnCl2.2H2O  material was chosen as the masking material because it has a high adhesive property to SiO2, does not react to the KOH etching solution and is corrosion resistance as well as low cost. The etching profile surface results and etch depth (Dz) were determined using topography measurement system (TMS 1200). The etching rate with 40% KOH during etching time of 30 minutes, 60 minutes, 90 minutes were 4.36 μm, 4.56 μm and 5.79 μm respectively. The optimum QCM surface isotropic profile was obtained at the etching rate of 4.56 μm / h by 60 minutes etching. 
Ch2FCF3 Gas Flow Rate Effects of SiO2 Plasma Etching Rate on Quartz Crystal Microbalance Antonius Prisma Jalu Permana; Dionysius Joseph Djoko HS; Masruroh Masruroh
Natural B, Journal of Health and Environmental Sciences Vol 3, No 4 (2016)
Publisher : Natural B, Journal of Health and Environmental Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (418.546 KB) | DOI: 10.21776/ub.natural-b.2016.003.04.1

Abstract

Effect of gas flow rate on the surface of quartz crystal SiO2 during plasma etching was studied. The etching process was applied using the capacitively coupled plasma (CCP) reactor generated with 100 W power AC generator at low frequency of 40 kHz using a gas flow of CH2FCF3. The main objective of this study was to determine the effect of changing gas flow rate on the plasma etching rate on the SiO2 surfaces. Gas flow rate was varied between 20-40 mL/min, while keeping all other plasma parameters constant. The etched surface of SiO2 was analyzed using white-light profilometer (Topography Measurement System (TMS 1200 Micro Lab)). The results show the physical etching processes influenced the rate of etching at a low gas flow rate, while the higher flow rate influence reactive ion etching (RIE) in the etching process. The maximum etching rate is found at 7.753 nm / min achieved in plasma etching process. 
Study of Adsorption and Desorption on Gold Metals by Biomass Saccharomyces cerevisiae. Thermodynamic Review Masruroh Masruroh; Lailatin Nuriyah; Siti Jazimah Iswarin; Eka Rahmawati
Natural B, Journal of Health and Environmental Sciences Vol 1, No 2 (2011)
Publisher : Natural B, Journal of Health and Environmental Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (55.194 KB) | DOI: 10.21776/ub.natural-b.2011.001.02.11

Abstract

A Study on biosorption of gold solution (Au) by Saccharomyces cerevisiae has been caried out. These studies included determination of optimum pH, optimum Au solution concentration,  isotherm and biosorption capacity based on termodinamycs theory, and mechanims of interaction between Au ion and Saccharomyces cerevisiae biosorben. Mechanisms of interaction were known with Au ion on Saccharomyces cerevisiae biosorben using aquadest and 1 M HCl. The result showed that the optimum adsorption process of Au solution by Saccharomyces cerevisiae biosorben took place on pH 5, adsorbat concetration of 100 mg/L was 2.2321 mg/g of yeast. The adsorption isoterm followed the Langmuir adsorption with regresion value of 0.8550 (R2= 0.8550), that indicates that the chemisorption process occurred on the first monolayer on the adsorbent surface. From the thermodynamics theory gives Gibbs free energy of the process a value of ΔG = -0.09195 kJ/mol and showing spontaneous physisorption process. The number of Au ion desorption by using HCL was 73.98%, whereas by using aquades it was 35.42%. It indicated that the main interaction between Saccharomyces cerevisiae biosorben and Au ion was chemisorption.