Materials Science Forum Vol. 1025

Abstract: The historical development of fire suppression technology evolved in the 1930s since the application of Halons as a fire extinguishing agent. The fire may cause tremendous losses to organizations. It affects the chain of businesses and the stability of the economic growth of a country. The key issues of greenhouse effects and safety and health as well contributes to the sudden change of the technology of fire extinguishing systems. The establishment of the Montreal Protocol and Kyoto Protocols controls the producers to develop, supply and use of environmentally hazardous gasses worldwide. Hence, promote global sustainable for upcoming generations. This paper is highlighting the reasons gas type fire extinguishing agents extensively used substituting conventional methods against fire. The fundamental equations of Ozone Depleting Potential and Global Warming Potential were properly discussed to show how severe these gasses exposed to the environment. The effectiveness of these gases as a clean agent in extinguishing the fire may convince prospect users to carry out the decision of changes. Potential extinguishing agents will be deliberated to investigate their needs as new fire suppression agents. It will be then to be suggested and recommended for further studies.

Abstract: Recent advancement on biological wastewater treatment is via granular sludge technology. It is widely known that, aerobic granular sludge has been developed in a batch operation since its discovery. Yet, most of the wastewater treatment plant (WWTP) is operated in continuous mode. Now, the real challenge is how to adopt the granular technology while maintaining present operation mode of WWTP. Thus, this study attempts to evaluate the feasibility of developing aerobic granular sludge in continuous airlift reactors feed with two different substrates, namely glucose and acetate. Two identical airlift reactors (6 L) were employed and operated at room temperature (30°C). Prior to the substrate feeding, both reactors were inoculated with seed sludge obtained from a palm oil mill anaerobic pond. One of the reactors was fed with 2000 mg COD L^-1 of glucose (ALR1) and the other reactor with 2000 mg COD L^-1 of acetate (ALR2). The hydraulic retention time (HRT) and organic loading rate (OLR) for both reactors were maintained at 4 days and between 0.2 to 0.5 kg m^-3day^-1 respectively. Dissolved oxygen was maintained between 5.0 and 6.0 mg O₂L^-1 and supplied by air compressor. The reactor performance was monitored based on COD removal. Aerobic granules developed throughout the study period was evaluated based on granules size and morphology, sludge volumetric index (SVI₃₀) and SVI₅/SVI₃₀ ratio analysis. Results showed that ALR1 demonstrated the formation of filamentous-type aerobic granules with most of the SVI₃₀ average at 100 to 190 mL g^-1. Ratio SVI₅/SVI₃₀ analysis was evaluated at 0.2 and 0.5. The largest granules size obtained during the experiment was about 600 μm on day-136 and average granules size obtained at 200 to 400 μm. ALR1 able to achieve 95% COD removal. For ALR2, round shaped aerobic granules were developed with average SVI₃₀ from 100 to 1000 mLg^-1. SVI₅/SVI₃₀ analysis indicated an average ratio between 0.7 and 0.9. The average granules size was between 30 to 50 μm and the largest was 78 μm on day-60. 90% of COD removal efficiency was obtained in ALR2. In conclusion, ALR fed with acetate had indicated better aerobic granules characteristics as compared to glucose fed reactor. Furthermore, the study demonstrated that to develop aerobic granules in continuous reactors is feasible.

Abstract: Acid Mine Drainage (AMD) is one of the consequences of environmental impact due to surface coal mining and has big challenge how to treat the AMD both active and passive treatment efficient and effectively. The most expensive method to actively raise the pH and concentration heavy metal reduction of this wastewater is the use of chemical additives. We present the development of passive treatment with Swampy Forest (SF) system as a new natural and sustainable method with lower costs, and greater environmental sustainability. The SF system consists of selecting organic matter and combining it with the planting of selected grass and tree species in the form of a forest constructed wetland. As a preliminary to the construction of the SF, a batch reactor system was used to carry out experiments to find the best individual grass species for SF as the development of AMD passive treatment. The four grass species selected were shown to reduce the concentration of Fe and Mn, which generally has out of threshold value, thus achieving the threshold parameter to comply with applicable regulations for managing mine wastewater.

Abstract: Vegetables are essential in human diet but unfortunately it may also contribute to heavy metals’ consumption. High consumption of water spinach may cause harmful health effects due to contamination by heavy metals. Two different parts of water spinach (Ipomea aquatica), namely: i) leaves and, ii) stem were collected from markets around Bandar Pusat Jengka and UiTM area to determine and compare selected metals’ (Mn, Cu, Zn and Pb) concentrations to the standard permissible limit set by Food and Agriculture Organization (FAO) and World Health Organization (WHO). The samples were prepared by wet digestion using a mixture of HNO₃ and H₂O₂ and then analysed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Heavy metals’ concentration ranges were recorded as follow; 0.130 – 9.410 mg/kg for Mn, 0.120 – 0.330 mg/kg for Cu, 0.200 – 2.470 mg/kg for Zn and 0.003 – 0.210 mg/kg for Pb. Concentration of Mn was higher than other metals. All concentrations of selected metals were below the maximum standard set by FAO/WHO except for leaves in sample A. Nevertheless, it should be noted that consuming the I. aquatica for a long time with excess amount of heavy metals may contribute to health effects.

Abstract: Processing of petroleum crude oil with high total acid number (TAN) lead to corrosion problems in oil refinery equipment, storage, facilities and even reduces the performances of the oil. The purpose of this study is to overcome the corrosion problem in oil refinery by reducing the TAN in the oil to less than 1 mgKOH/g. A 2-methylimidazole in ethanol with the aid of Ni/Ce (10:90)/Al₂O₃ catalyst through the catalytic deacidification technique. The catalyst was prepared by using Incipient Wetness Impregnation (IWI) methods on alumina beads as catalyst support and calcined at 800°C, 900°C and 1000°C. Ni/Ce (10:90)/Al₂O₃ catalyst was characterized by using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction Spectroscopy (XRD) and Brunauer-Emmett-Teller (BET) to study physicochemical properties of the catalyst. The results shows that Ni/Ce (10:90)/Al₂O₃ catalyst successfully reduced TAN in crude oil to 0.50 from 4.22 mg KOH/g at 1000°C calcination temperature and catalyst loading of 0.39% (7 beads). XRD analysis proposed Al₂O₃ and CeO₂ fcc was the active site for Ni/Ce (10:90)/Al₂O₃ catalyst. C-H alkanes stretching, -CH₂- alkanes stretching and pure metal oxides stretching modes were detected on the catalyst at wavelength of 2952.49 to 2852.82, 1599.38, and 862.81 to 537.27 cm^-1 respectively by FTIR analysis after catalytic deacidification process which indicates that there were impurities that have adsorbed on the catalyst surface. As a conclusion, the catalysts successfully reduced the TAN value of acidic crude oil to less than 1.00 mg KOH/g.

Abstract: Polyvinylidene fluoride (PVDF) reveals outstanding properties such as lightweight, high flexibility and temperature independence material compared to other polymers. In this study, PVDF as a function of molecular weight was prepared by using an electrospinning method in order to study the influences of the molecular weight of the PVDF membrane on the morphology. Analytical techniques such as field emission scanning electron microscope (FESEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD) were used to characterize the electrospun PVDF membranes. FESEM was used for morphology characterization and also to measure the diameter of fibers while XRD and FTIR were employed to examine crystalline phase membranes. The lowest molecular weight has the smallest average diameter of fibers. Besides, a combination of both α-phase and β-phase crystalline was showed by XRD and FTIR results. This is because the crystalline phases and membrane morphology depend on the polymer molecular weight. In this research, it was found that the largest β-phase fraction for the electrospun PVDF membrane is 80.25 % with a molecular weight at 180,000 g/mol.

Abstract: Polybenzimidazole (PBI) nanofiber membranes were prepared using electrospinning potential of 15 kV and 0.2 ml/h flow rate at different PBI concentrations (6.5 and 7.5 w/v%) with the solvent mixture ratio (DMAc:DMF) of 1:1 and 2:1, respectively. This study investigated the properties of the polymeric solution and the effects of solvent ratio and concentration on morphology, hydrophobicity and mechanical properties of PBI nanofiber membranes. The solvent mixture ratio and spinning solution properties are not significantly different than the effect of polymer concentration on the viscosity. The viscosity and surface tension of spinning solutions increases with an increase in the concentration of PBI. It was observed that the average diameter of nanofibers was 75 and 97 nm for 6.5 and 7.5 w/v% PBI spinning solution, respectively. Moreover, the contact angle values range from 111 to 125°. This observation reflects that the nanofiber membranes are hydrophobic. Another finding is that the nanofiber membranes with 7.5 w/v% of PBI showed excellent mechanical properties with the maximum stress value of 4.20 ± 0.29 MPa. The finding also shows that the polymer concentration on the spinning solution influences the structure and morphology of the nanofibers. On the other hand, the solvent mixture ratio does not have any significant impact on the nanofiber membranes properties.

Abstract: Phenolic resins are thermosetting material that is commercially produced via the condensation process of phenol and formaldehyde. However, due to the usage of petro-based materials in the production of phenolic resins, several approaches have been made, and one of the approaches is by substituting the raw materials, especially phenol, with lignin. In this study, acetosolv lignin was used to produce lignin-formaldehyde (LF) and compared with phenol-formaldehyde (PF) resin. The resinification reaction was conducted at 85 °C for 4h. The functional group, curing behavior and the shear strength of the resins was analyzed using FTIR-ATR, DSC and Universal Testing Machine, respectively. The formation of PF and LF resins was confirmed by the presence of the methylene bridge functional group at 1460 cm^-1. The curing curve shows the shift of LF resin to a higher temperature compared to the PF resin. Furthermore, the evaluation of bonding strength shows that LF resin possesses a low shear strength compared to PF resin. However, both resins pass to be adhesives for the manufacture of plywood panels based on standard JIS K-6852.

Abstract: Fiber morphology of 3 species of bamboo namely Bambusa vulgaris, Gigantochloa levis, and Gigantochloa scortechinii at age of 1, 3, and 5 years, was evaluated. It shows that different species of bamboo have different properties in terms of their fiber morphology that consist of fiber length, fiber diameter, and lumen diameter. Fiber diameter, fiber length, and cell wall thickness increased with the increasing of the bamboo age but the lumen diameter decreased when the bamboo gets older. G. levis at age 1 to 3 and G. scortechinii at age 1 have high potential to be the raw materials for the pulp and paper industry.

Abstract: Alkaline treatment has a function to disrupt hydrogen bonding in network structure and to remove some hemicellulose, lignin and extractives for efficient contact with the matrix when preparing composites. Kelempayan (Neolamarkia cadamba) particles were treated using 0.5, 1 and 2% sodium hydroxide (NaOH) solution at a temperature of 90 °C for 60 minutes periods of immersion. The particles were washed with running tap water to neutralize excess NaOH and oven dried at 80 °C. The treated particles were then grounded to a fine size before being sieved to 60 mesh size of sawdust. Finally, the treated samples were air dried before chemical analysis. The sampling and preparation of sawdust were carried out according to the TAPPI Standard T257 cm - 02 (2002). The changes occurring on Kelempayan’s surface were assessed using Scanning Electron Microscopy (SEM). Chemical analysis indicated that hemicellulose, lignin and extractives became decreased by increasing alkaline concentration. Morphological analysis showed that treated surface was cleaner and rougher than that of untreated.