Key Engineering Materials Vols. 594-595

Abstract: The eco-friendly synthesis of nanozeolite need to be developed in order to minimize the consumption of unwanted excess extracted solutions or solvents and maximize the utilization of beneficial wastes as its raw materials. Thus, the synthesis of nanozeolite NaA from rice husk ash (RHA) without extraction of silica from RHA and without organic template has been successfully achieved. Nanozeolite NaA was synthesized from rice husk ash (RHA) via this main step: aging the aluminosilicate suspension (3.190 Na₂O: Al₂O₃: 1.4SiO₂:235.07H₂O) for 3 days at room temperature with agitation rate of 150 rpm followed by heating at 55 °C for 18 hours. The nanozeolite NaA was confirmed by XRD, FTIR, FESEM and particle size distribution analysis where the highest particle size was in the range of 100 to 400 nm. Its efficiency in removing ammonium ions in aqueous solution was found to be better than that of microsized zeolite NaA thus proved that the lower particle sizes of zeolite NaA (nanosize) tended to have higher adsorption sites and higher exchange capacity.

Abstract: Biological degradation is one of the most beneficial and economical methods to clean up contaminated marine soils. Although biodegradation by microorganisms encourages the natural process of contaminant removal and serve as potentially cost-effective treatment, limited facts in microbes and contaminant interactions lead in treatment failure. The present study had identified the existence of potential microbes in marine soils dredged from the coasts of Peninsular Malaysia. These included the genera of Serratia, Vibrio, Enterobacter, and Pseudomonas. Among these, Vibrio and Serratia have potential to degrade oil and grease as well as Polycyclic Aromatic Hydrocarbons (PAHs). Irrespective of any additions of particular nutrients, the existence of these genera whereupon reduces the potential for bioaugmentation treatment. Major problem in bioaugmentation is rapid decline in number of introduce microbes due to abiotic or biotic stress. The first stage needed to develop treatment strategies are by understanding the environmental conditions and factors that limit the ability of microbes to degrade the contaminants. Considering these understanding, biodegradation treatments of contaminated dredged marine soils is ease to design. This theoretical framework therefore aims to assess on the bacteria capability to degrade correlated with the contaminant concentration.

Abstract: Waste tyres which are mainly generated from automotive industries have become a major environmental problem to the local authorities, the tyre industries and tyre dealer. When tyres are no longer usable due to worn-out, defect or service failure they are usually dumped in the landfill sites. Pyrolysis is a process of the thermal decomposition of waste tyres in the absence of air and the oxygen. Pyrolysis may be an environmentally friendly process to transforms used tyres into gas, oil, steel and carbon black waste. The rate of recovery is 45 wt % for fuel, 30 wt % for carbon black and 10 wt % for steel wires for each end-of-life tyres. In this paper, the potential use of pyrolised carbon black generated from pyrolysis process of waste tyres is investigated. From the physical analysis of this carbon black waste, it was observed that there is various refraction particles sizes from the sieve test and different morphologies gathered from SEM analysis. Moreover, X-Ray Fluorescence (XRF) and TGA/DTG analysis on the carbon black waste showed high content of inorganic additives such as Silica (Si), Calcium (Ca) and Iron (Fe) which contaminate the sample. The carbon black waste started to decompose at a lower temperature of 480°C to 680°C compared to standard black at 500°C to 740°C. The test results gathered in this paper will act as a base-line towards alternative material or to replace the commercial carbon black available in the market.

Abstract: Waste cooking oils are problematic disposal especially in the developed countries. In this paper, waste cooking oil is used as raw material to produce foam. The purpose of the study is to develop the high density solid biopolymer (HDB) by using hot compression moulding technique based on flexible and rigid crosslinking agents. Physical properties such as Scanning Electron Microscope (SEM) and density of HDB were examined. The acoustic study of HDB for flexible and rigid has been measured using impedance tube test according ASTM E1050 standard with multiple layers of thicknesses. It was revealed that higher thicknesses of HDB exhibit less sound absorption coefficients. This situation is occurred for both flexible and rigid HDB. The frequency also shifted to the left when the layers of HDB were increased for both materials. The highest increment was 63.46%, observed from two layers from flexible and rigid HDB. For the conclusion, rigid HDB showed that they could absorb more sound, thus having higher noise reduction coefficient (NRC) than flexible HDB at low frequency.

Abstract: Effective Microorganism (EM) technology was found as the credible solution to solve many environmental problems including wastewater issues. The EM which is in the form of EM mud ball was tested to be effectively used for waste treatment that comes from the factories, resident area, and also agriculture sector. Furthermore, the polluted rivers can also being applied with this product in order to improve the water quality. Until today, the halal issues caused by the ingredients of EM still are not clearly mentioned by the manufacturer and becomes a concerns to most of the Islamic country like Malaysia. As the solution, halal based source are suggested in utilization of Effective Microorganism (EM). The result of the experiment shows that EM mud ball has the potential to solve the problem regarding treating the wastewater as it positively reducing the level of turbidity.Keywords: Effective microorganism (EM), Halal based sourced, turbidity, waste treatment

Abstract: An investigation was conducted to determine an effective media condition for the growth of fresh and freeze-dried oyster mushroom mycelium. Fresh and freeze-dried mycelium sub-culture on liquid media obtained 0.3022 and 0.5081 maximum specific growth rate respectively. The doubling time for fresh and freeze-dried mycelium was calculated 2.2937 and 1.3642 correspondingly. On solid media, maximum specific growth rate for fresh and freeze-dried mycelium was obtained lower at 0.1636 and 0.3719 respectively. The doubling time for fresh and freeze-dried however, was calculated higher at 4.2368 and 1.8683 correspondingly. Freeze dried mycelium showed good recovery tendency after preservation at low temperature.

Abstract: In this work, Mg and Zn powder were used to prepare the Mg-Zn/β-TCP composites with different β-TCP composition by using powder metallurgy technique. The composite were mixed using ball mill and compacted at 500 MPa. The composites sintered at 450 °C in tube furnace for two hours. The effects of properties on Mg-Zn with different composition of β-TCP were studied. The results on the effect of β-TCP composition were analyzed in terms of density and microstructural analysis.

Abstract: Natural dyes represent a sustainable source of colorants, which are low cost and safer than synthetic dyes, concerning human health. The purpose of this study is to extract Vitex negundo L. leaves using supercritical carbon dioxide extraction and to identify the extracts potential as a dye. The extraction process has been conducted at different operating conditions by varying temperature from 40 to 65°C with an increment of 5°C at 20, 25, and 30 MPa within 60 minutes constant time. The extracts obtained at different conditions were analyzed using Gas Chromatography Mass Spectrometer (GC-MS) to determine the chemical compounds present. Increase of temperature increased the extraction yield, but further increasing the temperature above 50°C has reduced the yield. The effect of pressure gave two different patterns, in which the first one showed the yield kept increasing with pressure (20 to 30 MPa) at 40, 45, 50, and 55°C. The second pattern showed sudden reduction of yield above 25 MPa at another two higher temperatures. The highest extraction yield (13.94 mg/g) was obtained at 30 MPa and 50°C which considered as optimum operating condition. GC-MS analysis showed the presence of several phytochemicals including some flavonoid compounds, which are potential sources of dye.

Abstract: Poly (lactic acid) (PLA) is well known for their biodegradability and bioresorbable properties and these properties made them suitable in drug delivery system as drug carriers. PLA is relatively hydrophobic and lack of cell-recognition group to interact with biologically active molecules which reduce the surface compatibility of microspheres. In this project, alkaline hydrolysis was used to induce hydrophilic functional group on the microspheres surface. Alkaline solution at 0.01M and 0.1M was used to modify microspheres surfaces. The engineered surfaces were evaluated using Scanning Electron Microscopy and Water Contact Angle. 0.1M alkaline solution hydrolyzed microspheres at higher extends as compared to 0.01M, where partial microspheres disintegrated and porous structure was revealed. The water contact angle of PLA films shows decreased from 65 ̊ to range 42 47 ̊ after alkaline hydrolysis.

Abstract: In order to enhance its cationic sorption capacity, untreated rubber leaf powder (RLP) was functionalized using monosodium glutamate to produce potentially biodegradable cationic sorbent. The sorption behaviors of monosodium glutamate functionalised (MGRL) against Pb (II) in a batch system are investigated. The effects of various experimental parameters (e.g. initial pH, contact time) were investigated and the sorption kinetic was elucidated. The Pb (II) removal on MGRL increased as the initial pH increased. The effect of contact time revealed that the equilibrium is reached at 90 minutes. The Pb (II) sorption process on MGRL followed the pseudo-first-order rate kinetics. The Langmuir isotherm model with a maximum adsorption capacity of 109.953 mg/g was found suited to describe the adsorption process.