Key Engineering Materials Vol. 797

Abstract: Molecular modelling method has been extensively used by process simulators to forecast the expected outcome of certain processes. The objective of this study is to predict the behavior of standard and modified epoxy resins with water using molecular dynamic technique. An arbitrary cell containing adhesive and water molecules was built using the Amorphous Cell Module and dynamic simulation was conducted using Forcite module at two different temperatures; 20 and 50°C for both standard and modified adhesive. From the analysis, the mean square displacement (MSD) for water molecules in a standard adhesive system was higher than Albipox which leads to a higher value of diffusion coefficient. Higher MSD for water in the system with standard adhesive means that it is easier for water molecules to move in the system. It moves to a wider or larger area compared to the water with Albipox in the system. This also shows that the usage of Albipox was successful to control the moisture uptake of water. The predicted diffusion coefficient of water also follows the trend of the experimental data where it increased when the temperature increased for both systems. Based on the result presented in this paper, it has been concluded that molecular modelling was able to predict the interaction of standard and modified adhesive with water.

Abstract: The present study reports the synthesis of zinc oxide (ZnO) nanoparticles (NPs) using Jackfruit banana peel (Musa Species.) extracts (BPE) as reducing and stabilizing agent. This green synthesis is considered promising an alternative technique that cost effective, nontoxic and environmental friendly. Zinc acetate dehydrate solution ((CH₃COO)₂.2H₂O) was used as the precursor for ZnO synthesis and the concentration was varied in the range of 0.100 M – 0.010 M at constant pH of solutions, 12. The synthesized ZnO NPs were then characterized using fourier transform infrared spectroscopy (FTIR), ultraviolet visible (UV-Vis) absorption spectroscopy, x-ray Diffractometer and Brunauer-Emmett-Teller (BET). The band gap energy was found in the range of 3.44 eV - 3.58 eV while XRD analysis shows a crystalline structure in hexagonal wurtzite shape. These unique characteristics open the possibilities of various potential application in medical and industry as well as for development of antimicrobial agent for food packaging applications.

Abstract: In this study, Zinc Oxide (ZnO) Nanoparticles (NPs) were synthesized from banana peels (Jackfruit banana) extract (BPE) at different pH condition. The samples were then characterized to identify the optimum pH condition for producing ZnO NPs and at the same time determine the crystallite and particles size of ZnO. This paper covered a section of green chemistry since green application has become an attention nowadays. Slo-gel method is the method used to synthesize the ZnO NPS because the advantages in terms of eco-friendly, less time consumption, cost effective and easy to apply. BPE is one of raw material that has the ability to act as stabilizer and reducing agent. The samples were characterized using Fourier Transform Infrared Red (FTIR) Spectroscopy, UV-visible spectrometer (UV-Vis), X-ray diffraction (XRD) and Brunaner-Emmett-Teller (BET). It was found that the presence of ZnO were recorded from FTIR spectra at wavenumber 350-390 cm^-1 for all samples which indicating the presence of ZnO bond. The UV-Vis spectrometer was recorded to observe the absorption peak, the highest absorption peak at 367 nm and the band gap was 3.38 Ev at pH 12. XRD analysis showed the ZnO nanoparticles formed to have hexagonal wurtzite structure and the crystallite size between 16 to 23 nm and the smallest crystallite size was smallest at pH 12. BET analysis showed that the surface area of ZnO NPs between 15 to 53 m²/g and the average particles size of ZnO NPs between 20 to 66 nm. As a conclusion, ZnO NPs can be produced from BPE at optimum pH of 12.

Abstract: Waste cooking oil (WCO) is an under-utilized, highly abundant raw material from food industry. In this study, WCO was used to prepare solid polymer electrolyte (SPE) films via solvent-free method. WCO was first pretreated and converted into polyol using epoxidation and hydroxylation reaction. Then, WCO-based polyol was combined with diisocyanate, LiCF₃SO₃ and carboxymethyl cellulose (CMC) to obtain polyurethane SPE films. CMC was added to SPE as bio-filler to observe the effect on ionic conductivity and mechanical properties of SPE. SPE films were characterized using Fourier transformed infrared spectroscopy, electrochemical impedance spectroscopy, x-ray diffraction spectrometer (XRD), differential scanning calorimetry and tensile strength. Addition of CMC resulted in increase of ionic conductivity up to 1.19 x 10^-5 S/cm for 15% CMC. The ionic conductivity supported with reduced crystalline peaks intensity in XRD to show that the amorphous nature of SPE increased as more CMC added. Tensile strength also increased with addition of CMC and peaked at 10% CMC (34.17 MPa) due to effective hydrogen bond interaction between CMC and PU or salt. However, increased CMC amount further to 15% reduced tensile strength due to agglomeration of CMC particles. As a conclusion, addition of CMC is a viable method to improve both ionic conductivity and mechanical property of SPE.

Abstract: This paper represents the biodegradation characterization of thermoplastic starch (TPS) films derived from Tacca leontopetaloides starch; namely thermoplastic starch with glycerol as plasticizer (TPS/GLY), thermoplastic starch with glycerol added with acetic acid (TPS/ACE) and thermoplastic starch with glycerol added with acetic acid with rice husk biochar reinforcement (TPS/BCRH) after aerobic biodegradation under controlled composting conditions. From the experiments, scanning electron micrograph (SEM) of the films showed homogeneous and even surface before the biodegradation but changed into grainy and uneven after subjecting to 45 days of biodegradation. Mechanical properties of all TPS films reduced significantly as expected. Even so, adding rice husk biochar did offer some strength to the TPS formulation. However, Fourier transform infrared (FT-IR) analysis suggested that 45 days of aerobic biodegradation was not capable to alter the chemical structure of the films as the characteristic peaks of all films are quite similar to before the biodegradation took place. The study also found that Aspegillus sp was the degrading TPS microorganism.

Abstract: This study aims to investigate the interaction during the co-pyrolysis of Cangzhou coal and sawdust/rice husk. The synergistic is analyzed in the thermal behavior of the blends and the kinetics by thermogravimetric analysis (TG), also in the products yield (oil and char) from the fast co-pyrolysis and the oil characterization by GC-MS and UV fluorescence spectroscopy. Firstly TG experiment indicated the synergistic effect occurs during the co-pyrolysis process of the coal and rice husk occurs during the all the main pyrolysis (300-550°C) and that of the sawdust between 300-410°C (for the 50:50 and the 75:25 blends) and 300-550°C (for the 25:75 blend). Then the co-fast pyrolysis in a novel auger reactor increased the oil yield compared to the predicted values. The synergistic interaction promoted the oxygenated compounds, limited the SO_x emissions, was less reactive and did not promote the aromatic components.

Abstract: Food waste is a potential source of renewable carbon that can be utilized as a feedstock for biofuel production. Instead of disposing it in the landfills, food waste can be processed through thermochemical process known as torrefaction, which is conducted between 200°C and 300°C under inert atmosphere, to produce energy-dense biochar. Due to high oil content in the food waste, wet rendering process is introduced as a pre-treatment step to remove the oil from food waste. In this study, the potential of food waste as a renewable energy source is studied, where the biochar produced from direct torrefaction (DT) is compared with the biochar produced from torrefaction process that is preceded with wet rendering (WR) process. Food waste was torrefied in the fixed bed reactor at temperatures 220°C, 240°C and 260°C, with various residence times (15 min, 30 min and 45 min). The produced biochars were characterized in terms of its elemental composition, High Heating Value (HHV) and proximate analysis which includes moisture content, fixed carbon, ash content and volatile matter. It was found that the torrefied food waste shows improved physical properties when compared to raw food waste. The moisture content showed significant reduction while the fixed carbon increased with increasing torrefaction and residence time. This effects were further improved with WR, especially HHV which indicates that the WR process followed by torrefaction may be able to further improve the produced biochar.

Abstract: In this study, to convert high moisture content waste into bio-char, slow pyrolysis of cooked rice waste was proposed. The effects of temperature and duration of slow pyrolysis of cooked rice waste on the fuel properties of the biochar produced were investigated, namely the carbon content and energy density. The cooked rice waste was dried overnight at 80°C prior to pyrolysis to reduce moisture content. The carbon content was measured by using Thermo Finnigan Flash EA 1112 Series Elemental Analyser CHNS-O. Energy density was measured by using IKA Works C—5000 Control bomb calorimeter. Results demonstrated that pyrolysed rice waste at 250°C and 4 hour duration had the highest carbon content (60.30%). Moreover, the calorific values for pyrolysed cooked rice wastes demonstrated that biochar derived from cooked rice waste could be a promising alternative renewable energy source.

Abstract: In this work, the ignition and combustion characteristics of mixed rice straw and sewage sludge pellets in air atmosphere were investigated using a plasma combustion system. One common pellet shape (solid spherical pellet) and another new shape (hollow spherical) are used in this study. High-speed camera was used to record and observe ignition and combustion process of pellets. In case of hollow pellets, the shape and distribution of flame are found to be better compared to solid pellets. Also, it is clear that the values of volatile combustion times in case of hollow pellets are low compared to solid pellets. The overall heat transfer enhanced in case of hollow pellet due to the large area subjected to hot gases and the high surface to volume ratio. Hollow pellet consumed less time for internal ignition and volatiles char combustion compared to solid pellet. Volatiles and char combustion lasted for 63.05 and 61 s, respectively for hollow pellet while these values were found to be 72.8 and 83 s, respectively for solid pellet.

Abstract: Biomass-based pyrolysis is a thermo-chemical conversion of biomass feedstock with low oxygen supplied level to produce bio-char, bio-oil and bio-syngas products via slow, intermediate and fast pyrolysis, respectively. The specific yields from pyrolysis process depend on operating conditions to maximize outputs. Bio-char can be used as soil improvement, animal feed supplements, filter material, carbon storage, and energy source. This study has focused on the development a simulation model for slow pyrolysis process utilizing biomass from oil palm empty fruit bunches (EFB) in Aspen Plus software. The facts that EFBs are abundant in Malaysia and have huge feedstock potentials could be realized, among them, through process design dan analysis in the Aspen Plus. Simulation model was developed based on EFB proximate and ultimate analyses and aimed for optimal product fraction yields and for the elemental composition of the pyrolysis products, considering several factors or effects such as pyrolysis temparature, pressure and inert gas flowrate. Simulation results showed the optimal value of bio-char yield was 68.6 wt. % at 9 bars, 300 °C, and 0.1 kg/min of inert gas flow rate. Eventhough the developed simulation model was an equilibrium-based one, it is useful especially in determining the optimal values of the key effects for the slow pyrolysis process.