Materials Science Forum Vol. 964

Abstract: Bio jet fuel becomes one of the feasible solutions for jet fuel inadequate supply in Indonesia. However, study in this field by far has been limited. In this study, bio jet fuel was synthesized from Crude Palm Oil (CPO) by Hydroprocessed Esters and Fatty Acid (HEFA) facilitated by Ni-Mo/SiO₂ catalyst, in which the support was derived from rice husk ash. The study focused on investigating the influence of catalyst-CPO mass ratio and temperature of the catalytic process. Experimental works consisted of silica-based catalyst preparation via impregnation method, followed by sample assessments. Catalytic reactions were conducted at 20-50 bars, with temperature of reaction 300°C and 400°C. Catalyst performance were evaluated from crystallinity, composition, and activity in the reaction. Catalyst characterization shows an amorphous structured with high dispersion of Ni-Mo in rice husk ash have been produced. The HEFA process successfully obtained bio jet fuel (C₁₀-C₁₅ hydrocarbons) with yield and selectivity of 45.17% and 45.46%, respectively. Overall, a systematic approach shows rice husk ash has potential to be developed as a catalyst support for bio jet fuel production from crude palm oil.

Abstract: CO emission is one of biggest problem in environmental sector due to increasing number of motorcycle user in every years. CO is poison gas which directly affects on the public health and earth’s atmosphere. The aim of this research to developed catalyst in catalytic converter system to oxidize CO to CO₂ by using MnO₂/zeolite NaY. Zeolite NaY was synthesized by using hydrothermal method following by wet impregnation to form MnO₂/zeolite NaY, then the composite was characterized by XRD, FTIR, SEM-EDX, N₂ physisorption, and catalytic activity oxidation of CO was carried out using 4 tag motorcycle. The XRD result represent zeolite NaY synthetic has similar diffraction peak with zeolite NaY (JCPDS 39-1380), then infrared spectrum exhibit T-O-T at fingerprint area which exhibit vibration of zeolite NaY. Octahedral crystal was successfully observe by using SEM which represent zeolite NaY crystal similar with previous study. N₂ physisorp shows that the composite has type IV of isotherm which exhibit the micropore and mesopore was form into material. Then, MnO₂/zeolite NaY has good thermal stability as well as catalytic activity for CO oxidation, where the longer reaction time successfully to reduce the concentration of CO. Conversely, CO₂ concentration dramatically increase as function of reaction time.

Abstract: Siwalan (Borassus flabellifer L.) is a palm family that is widely planted in the Tuban area of ​​East Java. Siwalan sap has a relatively high sugar content of about 10-15 g / 100 ml. The sap is obtained by tapping the inflorescences. In general, siwalan sap is used for fresh drinks or alcoholic beverages with maximum storage in 3 days. Based on the sugar content in the sap of siwalan, acetic acid products can be made through fermentation of glucose to ethanol, then the ethanol is fermented into acetic acid. Acetic acid is widely used as a preservative of food and health drinks. The purpose of this research is to study the effect of ethanol fermentation aerobic pH on acetic acid product. Anaerobic fermentation uses saccharomyces cereviceae to produce ethanol, and aerobic fermentation uses acetobacter aceti for acetic acid production. In aerobic ethanol fermentation using pH 3; 3.5; 4 and 5. The concentration of ethanol was analyzed using GC ULTRA Scientific Gas Chromatography, DSQ II detector, and MS 220 column. Acetic acid produced from the aerobic fermentation process was analyzed using an alkalimetric method. Anaerobic fermentation uses Saccharomyces cereviceae with 1-day log phase, while aerobic fermentation uses acetobacter aceti with a 5 day log phase. Aerobic fermentation to produce acetic acid was observed in 5 days to obtained maximum acetic acid concentration, the highest acetic acid concetration is about 2.595 g/l and yield of acetic acid is obtained 0.519% (b/v) at pH 5. Low acetic acid concentration due to low intitial sugar content in siwalan sap.

Abstract: In this work, Fe₂O₃ nanooval is successfully synthesized with variation of glycine composition of 9, 12, and 15 mmol at hydrothermal temperature of 160 °C. The Fe₂O₃ nanooval is indexed by XRD as α-Fe₂O₃. SEM and TEM images show that the 12 mmol of glycine has the largest diameter with the perfect nanooval form. Nyquist plot shows that the 12 mmol of glycine sample has the best conductivity value of 8.26x10^-5 S/m. The CV of sample 12 mmol delivers the best intercalate/de-intercalate with ΔV of 0.82 V. The 12 mmol sample shows the largest specific discharge capacity of 631.62 mAh/g. It is attributed to high conductivity and high kinetics reaction of Li ion during charge-discharge process. Therefore, Fe₂O₃ nanooval is a promising candidate as anode for lithium-ion battery.

Abstract: Copolymer gel contains zwitterionic betaine N,N-dimethyl(acrylamidopropyl) ammonium propane sulfonate (DMAAPS) and thermosensitive N-isopropylacrylamide (NIPAM). Later, they were employed as reversible Zn (II) and Pb (II) adsorption-desorption in aqueous solution. The effects of temperature, monomer, cross-linker concentration, and type of ions on the swelling degree, and the adsorption amount of Zn (II) and Pb (II) ions onto the gel were investigated. In addition, the adsorption-desorption reversibility of ions was also examined. The adsorption ability and swelling degree of the gel were significantly influenced by temperature, monomer, and cross-linker concentrations. The amount of ions adsorbed onto the gel was inversely proportional to its temperature at various monomer concentrations. The swelling degree of the gel with NIPAM to DMAAPS molar ratio of 9:1 and 8:2 decreased with the increase of the temperature. However, for the gel prepared with NIPAM to DMAAPS molar ratio of 7:3, the swelling degree increased significantly as the temperature increased. It was obtained that the swelling degree of the gel in Zn(NO₃)₂ solution was higher than the swelling degree of the gel in Pb(NO₃)₂ solution. In contrast, the amount of ions adsorbed onto the gel in Zn(NO₃)₂ solution was slightly lower than in Pb(NO₃)₂ solution. Copolymer gel prepared with NIPAM to DMAAPS molar ratio of 8:2 exhibited the highest adsorption ability and swelling degree in Zn(NO₃)₂ and Pb(NO₃)₂ solutions. In addition, the copolymer gel of NIPAM-co-DMAAPS showed the reversible adsorption-desorption ability toward ions up to three cycles.

Abstract: In this work, Li_1.6Mn_1.67O₄ is successfully prepared by solid state reaction method and firstly prepared as adsorbent for geothermal fluid of Lumpur Sidoarjo. XRD shows the all samples are indexed as Li_1.6Mn_1.67O₄ with spinel structure. The further increase of calcination temperature, diffraction peaks of Li_1.6Mn_1.67O₄ are growing strong and sharp, implying an improved crystallinity and an increased grain size. SEM images of LMO adsorbent show irregular shape with particles size in the range of 15-52 μm. Li_1.6Mn_1.67O₄ at 700 oC has the highest capacity of lithium adsorption with capacity of 29.8 mg/g. It is attributed to the high crystalline of Li_1.6Mn_1.67O₄ at 700 oC compared with other samples. In addition, the higher calcining temperature will result in the increasing grain size and crystallinity that enhance the adsorption performance of the Li_1.6Mn_1.67O₄ adsorbent.

Abstract: In-situ transesterification method without catalysts to produce biodiesel (fatty acid ethyl esters, FAEE) from rice bran using subcritical water ethanol mixture has been investigated. This method was found to be efficient since the rice bran oil (RBO) extraction and reaction of RBO into FAEE occur simultaneously. In this process other chemical (ethyl levulinate, EL) was also formed along with FAEE. EL can be used to improve the biodiesel quality by improving the low temperature properties of biodiesel. In this study effect of co-solvent types (without co-solvent, ethyl acetate, chloroform, and n-hexane) and water ethanol ratio (20%, 40%, 50%, 60% and 80%, v/v) on the content and yield of FAEE and EL at subcritical water ethanol mixture (T= 160°C, P= 80 bar, and t= 2 h) were investigated systematically. The content and yield of FAEE and EL obtained was found to be affected by the type of co-solvent. The content of FAEE and EL obtained without co-solvent (ethanol and water polarity index were PI=5.2 and PI=10.2, respectively) and with co-solvent of ethyl acetate (PI= 4.4), chloroform (PI= 4.1) and n-hexane (PI= 0.1) were 55.80% and 3.92%, 68.63% and 1.15%, 65.56% and 2.14%, and 62.00% and 0.93%, respectively. Higher polarity index of co-solvent extracted more RBO, as consequent the yield of FAEE (79.79%) obtained was higher using ethyl acetate as co-solvent. This data also suggested that RBO contains more free fatty acids (FFA= 63.59%) rather than of triglycerides (TG= 24.94%). The content and yield of FAEE and EL decreased with increasing water ethanol ratio. The highest content of FAEE (60.57%) and EL (8.48%) and yield of FAEE (78.03%) and EL (10.92%) were obtained using water ethanol ratio of 20%, v/v.

Abstract: Utilization of brown algae especially in Madura, where it’s close to Surabaya, only limited for food. This become a reference for developing and increasing the potential of this algae by extracting one of the ingredients, namely alginate. This paper deals with the characterization of sodium alginate extracted from sargassum sp. using modified-purified calcium routes. The extracted sodium alginate will be further used as composite hydrogel materials and compared with commercial sodium alginate. Hereafter, the synthesized composite is expected to be bio-ink for 3d printer. Chemical composition analysis were analyzed using X-Ray Fluorosense (XRF) followed by Fourier-transform infrared spectroscopy (FTIR) analysis to identify the functional group of composite and X-Ray Diffraction (XRD). Furthermore, viscosity bath is performed to compare the viscosity of extracted and commercial one. The result shows that modified-purified calcium routes in the extraction process of sodium alginate is desirable for improving their properties. Interestingly enough, with the goal of using it as bio-ink in 3d printed fabrication, the synthesized composite shows viscosity, 300 cSt, which meets the criteria for bio-ink in 3d printer.

Abstract: Stainless steel 316L is one of material that commonly used as medical bone implants. The needs of bone implants is quite high, even increases each year. However, bone implants itself has risks associated with bacteria and fungi. Various microorganisms can act as pathogens that have the abilityto stick to the surface of the implant material and forms biofilms that initiating infection inside the body. The method that can be used to prevent the infection is surface modifcation by applying antimicrobial coating on the implant material surfaces. Scientifically, silver (Ag) and zinc (Zn) are materialsthat have good antibacterial and biocompatibility properties. In this study, AgZn was deposited on SS 316L substrate using Radio Frequency (RF) Sputtering method. The aims of this study are to analyze the effect of the deposition time (15 minutes till 45 minutes). The surface area ratio of target material is 80% Ag 20% Zn. The morphology, mechanical properties, and antimicrobial properties of the thin film were studied. The variations of deposition time cause the difference in AgZn thin film thickness deposited on the surface of the substrate. The thickest thin film was obtained at 45 minutes deposition time, which is 1.61 μm thickness. Deposition time can also increase surface roughness and antimicrobial ability due to agglomerization of Ag and Zn on the surface of the sample. The best antimicrobial ability is found at deposition time of 45 minutes, resulting 11,3 mm of inhibition zone width

Abstract: Amoxicillin trihydrate suits to be encapsulated into a modified matrix to increase its bioavailability. In this study, the effect of drug loading methods on drug dissolution mechanism from chitosan-poly(N-vinylpyrrolidone) hydrogel with CaCO₃ as the effervescent agent has been studied. It was found that the encapsulation efficiency of in situ and post loading methods were 93% and 75%, respectively. The dissolution values were 94% and 98%, respectively for in situ and post loading. The dissolution test data was incorporated into zero-order, first-order, Higuchi and Korsmeyer-Peppas models to evaluate the kinetic and the mechanism of the drug dissolutions. The in situ loading method fits well to first-order model (R² = 0.9772), while the post loading method fits well to Higuchi model (R² = 0.9880). Based on Korsmeyer-Peppas model, the dissolution mechanism of in situ loading was Fickian diffusion (n = 0.4024), while post loading was a combination of diffusion and erosion (n = 0.5532). From the SEM images, it showed that the surface and cross-sectional of the post loading method hydrogel formed pores and pore channels, both before and after the dissolution test. Meanwhile, on the surface and the cross-sectional of in situ loading method hydrogel had pores and pore channels only after dissolution test.