Oral Presentation Abstracts GREEN SYNTHESIS OF FE-ZNO NANPARTICLAES VIA HIBISCUS ROSA-SINENSIS LEAF 01 EXTRACTS FOR PHOTOCATALYTIC DEGRADATION OF PALM OIL MILL EFFLUENT Presenter: Chai Huey Yee Malaysia is the second largest palm oil producer in the world that generates massive amount of palm oil mill effluent (POME). The polluting properties of POME such as very low pH, high chemical and biological oxygen demand, towards the environment without proper treatment are raising public awareness. Heterogeneous photocatalysis utilizing semiconductor catalyst can photodegrade organic pollutants into harmless products under light irradiation. Zinc oxide (ZnO) is one of semiconductors that has been widely used for photocatalytic degradation to treat environmental pollutants. In recent years, green synthesis of ZnO nanophotocatalysts using eco- friendly materials like plant extracts has become popular among researchers due to their phytochemicals present in the leaf that act as strong reducing and stabilizing agents. In this study, a green reflux method was used to synthesize iron doped ZnO (Fe-ZnO) nanoparticles using Hibiscus rosa- sinens/s leaf extracts. The synthesized Fe-ZnO nanoparticles were characterized by different techniques such as UV- vis diffuse reflectance spectroscopy (UV -vis DRS), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTlR) and vibrating sample magnetometer (VSM) analysis. The prepared Fe-ZnO performed excellent UV photodegradation on POME as compared to those of pure ZnO and commercial TiOz. The effects of operating parameters were studied by varying the initial pollutant concentration, solution pH and catalyst loading to obtain the optimum photocatalytic degradation process. VALORISATION OF RICE STARCH AS NATURAL COAGULANT IN POTABLE WATER 02 TREATMENT Presenter: Chua Siong Chin Coagulation process is widely used in most of the water treatment due to its excellent efficiency in removing the pollutant. Despite the efficiency of the process, the chemical coagulant that is used in the process poses two nonnegligible disadvantages in human health and environmental aspect. Therefore, this paper investigates the performance of rice starch in potable water treatment and optimize the operating conditions to evaluate the feasibility of rice starch to be applied in the water treatment industry. Response surface methodology (RSM) is useful to optimize the operating conditions especially for industrial purpose in order to reduce the operating cost, while maintaining the quality. The three significant factors, dosage of starch, pH and settling time are optimized through Box-Behnken design (BBD). The ANOVA result shows that the model and the three operating factors are significant with the p-value less than 0.05. The optimum conditions (within the designed range) of > 89% of turbidity reduction are with mg/L dosage of starch and 20 minutes of settling time pH 3. Besides, increasing the dosage of starch can greatly reduce the settling time, meanwhile, achieved the similar result. 89% turbidity reduction can be achieved as well with 40 mg/L dosage of starch and 1 minute of settling time at pH 3. The settling time is reduced to 20 times lower which greatly enhancing the feasibility of starch to use in the water treatment industry. However, pH 3 may not be economical feasible in most of the water treatment plant. Therefore, another set of optimum conditions is generated, and the range of the pH is strictly set pH 6.5 — pH 9. The maximum turbidity reduction can be achieved within the specific range is 63.62% and the optimum conditions are with pH 6.5, 19.41 mg/l of starch, and 20 minutes of settling time. The results shows the use of conventional rice starch solely is still insufficient to achieve turbidity reduction up to 96%. Therefore, alum is still needed in water treatment, but the use of conventional rice starch can greatly reduce the settling time of the floc (up to 20 times lower).
SIMULTANEOUS PALM OIL MILL EFFLUENT DEGRADATION AND ELECTRICITY 03 PRPODUCTION IN UV-LIGHT PHOTOCATALYTIC FUEL CELL Presenter: Kee Ming Wei Photocatalytic fuel cell (PFC) using ZnO/Zn photoanode and CuO/Cu photocathode was successfully established for simultaneous palm oil mill effluent (pome) treatment and the electricity production from the POME. The photoelectrodes were characterised by field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and fourier transform infrared (FTIR) spectroscopy. The ZnO/Zn photoanode was observed to be uniform nanorods with size of 1000 — 1200 nm The CuO/Cu photocathode was uniform nanoflakes in the length of 2143 — 2857 nm and width 286-571 nm. The EDX analysis revealed the Zn and O on the photoanode and the Cu and O on the photocathode, respectively. As-established PFC was used to examine the COD and colour removal of POME, and its electricity generation under 240 minutes of UV irradiation. The results suggested that the as-prepared ZnO/Zn photoanode displayed higher COD (71 %) and colour (58 %) removal as compared to commercial ZnO/Zn photoanode. Such a system exhibited a greater short circuit current density (0.0797 mA cm -2 ) and maximum power density (0.0121mW cm -2 ). The presence of 0.2 M sodium chloride as supporting electrolyte completely remove the COD and colour from the PFC system with the peak current density of 0.2113 mA cm -2 and maximum power density of 0.0337 mW cm -2 . VIRULENCE AND BIOCIDE SUSCEPTIBILITY OF PLANKTONIC AND SESSILE Legionella 04 pneumophila Presenter: Chay Min Jie Legionella pneumophila causes respiratory infections which may be fatal as in Legionnaires' disease. These bacteria are found in natural and artificial aquatic environments, such as waterfalls, water cooling towers, and water distributing systems where they exist as free-living plankton or sessile cells in biofilms anchored onto surfaces. In this study, planktonic and surface-attached biofilm cultures of L. pneumophila ATCC 33152 are compared for their expression of virulence factors and susceptibility to a chlorine-containing biocide commonly used for the disinfection of water systems. The bacterium was grown in Feeley Gorman Broth in 6-well tissue culture plates, using an inoculum of 10 7 CFU/ml. After 7 days of incubation at 25°C, in 5% C0 2 , planktonic and sessile biofilm cells we re harvested for RNA extraction and quantification of 10 virulence and 2 quorum sensing genes by RT-qPCR (Rotor-Gene). For the biocide susceptibility testing, 10% sodium hypochlorite (ChemSoln), diluted in water to liberate 0.1-10.0 ppm of free chlorine, was added into the 7- day L. pneumophila cultures. After further incubation for 3 days, both planktonic and sessile cells were harvested for the measurement of cell mass using McFarland standards. The proportion of dead and living cells was estimated using the Bacterial Viability Assay kit (Abcam) and a microplate reader that measures amount of fluorescence emitted from stained cells. The RT -qPCR results showed no significant changes in the expression of the virulence and quorum sensing genes with the exception of a 1.5-fold downregulation in the expression of the icmk gene (T value<0.05) in biofilm cells. This gene is one of the genes in the icm/dot system which is a major pathogenesis system in Legionella that has been shown to be involved with intracellular growth and conjugation. lts downregulation in biofilm cells is similar to the observation made by other workers that when conditions are favourable for L. pneumophila "replication (as in a young biofilm), traits (such as the icm/dot system) that promote transmission are repressed. The biocide susceptibility test results showed incomplete killing of L. pneumophila in both broth culture and biofilms, even up to 10ppm of free chorine. There was no increase in killing with the increase of free chlorine from 0.1ppm to 10ppm. The proportion of dead cells, however, was consistently higher in biofilms (68% to 91%) compared to planktonic cultures (47% to 55%) at all concentrations of free chlorine tested. This unexpected result could be due to nutrient depletion in the densely populated biofilm rather than a greater susceptibility of biofilm cells to chlorine, compared to planktonic cells.
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