Materials Science Forum Vol. 1000

Abstract: Bio-Jet could be produced by the synthesis of vegetable oil through the hydrodeoxygenation, decarboxylation, decarbonization, and catalytic cracking process. Physical characteristics, activities, and selectivity of the catalyst used will determine the rate, conversion, and yield of the reaction that being carried out. This study aims to compare and obtain the best characteristics of NiMoP/γ-Al₂O₃ catalysts synthesized using two types of preparation, impregnation and microwave polyol methods, which will be used for bio-jet production. The impregnation method takes more than 24 hours for catalyst preparation, while microwave polyols that use microwaves can synthesize catalysts faster. Both catalysts have almost the same loading on the weight of the catalyst, which in the microwave polyol method has a more dispersed promotor and active site, although the crystallinity level is deficient and tends to be amorphous compared to the impregnation method with high crystallinity. In bio-jet synthesis reaction with operating conditions of 5% catalyst loading by comparison to Coconut Oil, 400°C, and 15 bar, the conversion, yield, and selectivity of catalyst impregnation were 91.705%, 47.639%, and 84.511%, while microwave polyol catalysts were 90.296%, 42.752%, and 82.517%, respectively. In conclusion, microwave polyol provides a more effective and efficient preparation method.

Abstract: The conductive polyaniline (PANi) with fine particles of sizes from 724 nm down to 191 nm has been successfully synthesized through chemical oxidation reaction. The synthesis of PANi was carried out in acidic media under HCl 1.5 M solution using ammonium persulphate (APS) as an oxidizing agent in the presence of anionic surfactants. Two different types of surfactant respectively Sodium Octyl Sulphate (SOS) and Sodium Dodecyl Sulphate (SDS) were brought into an investigation on the effect of the surfactant chain length of C₈ and C₁₂ to the particle size formation. Such molecular chain length is responsible for the particle size growth rate. It was found that the average particle size of PANi decreased gradually by the addition of SOS and SDS surfactants with 1 % concentration each. The particle of PANi with sizes 296 nm and 191 nm was obtained as analyzed by Particle Size Analyzer (PSA). These sizes are far below 724 nm, which obtained from the same reaction but with surfactant free. Other supporting indicators showed that the pH of reaction solution was somewhat more acidic after 7 hours of reaction when the surfactant with pH value range within 0.7 – 1.4 presence. The temperature of solution increased with time following the energy released reached 30-31°C within the first 30 minutes, which was lower when compared with that of surfactant free.

Abstract: Micro-fibrillated celluloses (MFCs) are made from oil palm empty fruit bunches (EFB). EFB is processed through several stages of the process, including washing, alkalization, and bleaching to remove impurities, lignin, and hemicellulose. Each treatment stage was characterized by differential scanning calorimeter (DSC) and thermogravimetric (TGA) analysis. Morphological analysis was characterized using Scanning Electron Microscope (SEM). The process results show that MFC has an average length and thickness of 450 and 80 microns for coarse fibers respectively, averaging 50 and 5 microns for fine fibers, respectively. Fibrillation fibers appear on the surface of fibers which are treated using alkalization and bleaching processes. The TGA results showed a decrease in weight occurred at a temperature of 40 to 109 °C for the first stage of the heating process and at a temperature of 247 to 382 °C for the second stage. The decrease in fiber weight is caused by evaporation of water content and degradation of cellulose compounds at each stage. The glass transition temperature of MFC was obtained at 236 °C. The thermal stability of cellulose from fibers treated using alkalization and bleaching processes proved the formation of cellulose crystals. Removal of lignin and hemicellulose is shown by the absorption of O-H and C-C bonds in FTIR spectroscopy. From these results, it is stated that micro-fibrillation cellulose is formed well through a series of processes given.

Abstract: Automotive industries are trying to reduce the weight of cars by replacing parts that are made of steel and aluminum with lighter material but equally strong. It is an emerging trend in these industries to utilize polypropylene reinforced with natural fiber as the alternative lightweight material. PP-natural fiber composite is projected to have market growth with compound annual growth rate (CAGR) of 9.5% within 2018-2025. Blending PP with natural fiber is a challenging process considering these two materials are not compatible enough to produce composite with desired mechanical properties. Prior treatment to the fiber is required to improve its compatibility with PP with cautionary that it does not degrading the mechanical strength of the fiber. The aim of this work was to study the effect of chemical treatment on Kenaf fiber to the tensile strength of the fiber. Kenaf fiber was bleached with NaClO solution at various concentration (1-10% v/w), temperature (25-55°C), and duration (1-6 hours). The effect of bleaching treatment to the chemical structure and the tensile strength of the fiber was analyzed using FTIR and UTM respectively. This study showed that the fiber with highest tensile strength was the one that treated with NaClO solution with concentration 1% v/w, at 25°C for 1 hour. This treatment removed impurities for the surface and reduced some amorphous part of the fiber. However further increasing NaClO concentration, mixing temperature and duration will damage the cellulose chain in Kenaf fiber which will decrease the mechanical strength of the fiber.

Abstract: Clean water is essential source for household purpose. However, many surface water contain high salt concentration was found. In this work, membrane was made using tetraethyl orthosilicate (TEOS) as silica precursors and citric acid as single organo catalyst. Membranes were calcined at 200 and 250 °C using Rapid thermal processing (RTP). All membranes were tested via pervaporation. Pervaporation processes allow membrane to separate salt from water as vapour phase with vacuum condition required. Permeate was collected in the cold trap after condenses. This study focus to the performance of organo silica membrane in variance of refluxed 0 and 50 °C and feed concentrations (0.3, 3.5 and 5wt% NaCl) at room temperature (~25 °C). Optimum condition was obtained at reflux 50 °C with high siloxane and Si-C bonds. Carbon content from citric acid promote silica network more strength. The good performances in variance feed concentration were also showed at reflux 50°C with 0.3324 kg.m-2.h-1 (0.3 wt%), 0,2290 kg.m^-2.h^-1 (3.5 wt%) and 0.2168 kg.m^-2.h^-1 (5 wt%). These membranes are categorized as mesoporous and achieve excellent salt rejection >95%.

Abstract: A ceramic membrane has been produced from a natural zeolite. A series of samples has been sintered at range temperature from room temperaure to 900°C. The influence of the sintering temperature on the specific surface area, pore diameter, and surface roughness has been investigated. It has been found that a decrease for value of the specific surface area and average pore diameter from 300°C to 900°C was attributed to a change of the crystalline structure of tridimite from partially to fully crystallized samples. The fabricated membrane has been used successfully to evaluate the separation performance during the treatment of coconut sap. The membranes have a steady state flux from 0.12 to 0.22 mL/min.cm² at an applied pressure of 1 bar.

Abstract: Smoking can cause various ongoing complications in the body. One of the dangerous components of cigarette smoke is carbon monoxide which is one of the most toxic pollutants produced from cigarette gas emissions. Reducing levels in the air can utilize the adsorbent in the form of activated carbon which has the capacity and selectivity to these pollutants. Activated carbon was prepared from corn stalks which were activated by KOH at 750 °C based on previous research. The activated carbon which produced have Iodine number equal to 602 mg/g and SBET reached 599 m²/g. To strengthen the adsorption power, the results of activated carbon will be modified by impregnation of NiO metal. Metal impregnation varied with loading percentage 0.5, 1 and 2%. Modified activated carbons were then characterized by the Iodine Number test, BET test, SEM test, and EDX test. Each of the modified activated carbon will be tested for the capacity and selectivity of adsorption of CO and cigarette smoke. The best modified activated carbon is Mod 0.5% with Iodine number equal to 844 mg/g and SBET reached 839 m²/g. The best adsorption ability is obtained by 0.5% NiO-modified activated carbon which able to reduce CO gas levels by 29.9% and for cigarette smoke reaching 82.16%.

Abstract: The technology of natural gas adsorbed can be called Adsorbed Natural Gas (ANG) technology use porous adsorbents to adsorb natural gas. The material is activated carbon (AC), which has a large specific surface area. Activated carbon made from cassava peel waste because of abundance as agricultural waste in Indonesia. Cassava peel has a high cellulose and lignin content. Cassava peel through the carbonization process with furnace temperature 500 ° C in vacuum condition for 1.5 hours. Then, chemical activation with a different activator agent KOH and NaOH by mass ration (3:1). After that, physic activation with N₂ and CO₂ gas of 150 mL/minute using temperature muffle furnace 750 ° C. Product of physic activation modified using (Ni (NO₃)₂). Characterization of activated carbon performed with iodine test, SEM, EDX, adsorption, and desorption testers. The best of activated carbon is activated carbon impregnated KOH and with physic activation at 750 ° C, which has 612 mg / g of iodine number. Then, after activated carbon modified using (Ni (NO₃)₂) has the best performance with 1% NiO, has 662 mg / g of iodine number, and 657 m2 / g of S_BET. Then, activated carbon through adsorption and desorption test by ANG technology has 0.02928 kg/kg of adsorption capacity and 39.17% of desorption percent.

Abstract: Carbon capture storage provides an alternative to reducing global warming. In order to reduce the cost of carbon capture storage, high mass transfer packings for CO₂ absorption from flue gas is an alternative. The study modeled and numerically simulated CO₂ absorption by monoethanolamine solution with super mini ring contactor. The model considered the effect of the mass and momentum transfers, as well the chemical reaction. The simulation results show that the driving force of the reactive absorption is higher than the ordinary absorption in term of the low concentration of CO₂ in the liquid phase. The CO₂ concentration in the bulk gas is approximately 7.56 mol/m³. It decreases to around 5.75 mol/m³ after crossing the concentration boundary layer.

Abstract: The self-assembly of block copolymers has attracted attention for many decades because it can yield polymeric nanoobjects with a wide range of morphologies. Membrane emulsification is a fairly novel technique for preparation of various types of emulsions, which relies on the dispersed phase passing through a membrane in order to effect droplet formation. In this study, we have prepared polymeric nanoparticles of different morphologies using self-assembly of asymmetric block copolymers in connection with membrane emulsification. Shirasu Porous Glass (SPG) membranes has been employed as the membrane emulsification equipment, and poly (oligoethylene glycol acrylate)-block-poly (styrene) (POEGA-b-PSt) copolymers prepared via RAFT polymerization. It has been found that a number of different morphologies can be achieved using this novel technique, including spheres, rods, and vesicles. Interestingly, the results have shown that the morphology can be controlled not only by adjusting experimental parameters specific to the membrane emulsification step such as membrane pore size and pressure, but also by changing the nature of organic solvent. As such, this method provides a novel route to these interesting nanoobjects, with interesting prospects in terms of exercising morphology control without altering the nature of the block copolymer itself.