Considerable air quality and emission data gathered in Metropolitan Manila (MM) led to the develo... more Considerable air quality and emission data gathered in Metropolitan Manila (MM) led to the development of automobile exhaust treatment catalysts as well as their continued improvement. Findings of a 5-year (1993-1998) collaborative work on the development of base metal oxide catalysts for automobile exhaust are summarized here. One study in 1991 reveals an average 16% increase in the number of motor vehicles in MM where 16% are new and the rest are old ones. Another study in 1992 shows the CO and hydrocarbon emission levels from different types of motor vehicles in MM as a function of the age of the vehicle, type of fuel, and the operating condition. Reports of the Department of Environment and Natural Resources (DENR) and other related studies also provided data showing the quality of air in MM. Currently, there are several requirements to further improve the catalyst performance towards the reduction of NO X and to develop catalyst-sorbent for simultaneous NO X-SO X removal. This is so because of the present condition of rain acidification that is found in certain places in MM. These air quality and emission data are needed not only to establish practical emission standards for motor vehicles and the stationary industries and power plants but also in the development of technologies for air pollution control and other clean technologies for cleaner air in the country.
ASEAN Journal of Chemical Engineering, Aug 6, 2012
The nano-TiO 2 photocatalysts doped with Iron and Niobium for dye wastewater treatment were prepa... more The nano-TiO 2 photocatalysts doped with Iron and Niobium for dye wastewater treatment were prepared by temperature-controlled sol-gel method. The effects of these dopants on the physical and chemical properties of TiO 2 were compared with the commercially available Degussa TiO 2 P25. Among these characteristics are crystalline size, the presence of absolute anatase phase, band gap energy and specific surface area. The characterization data were correlated to photocatalytic activities using Turquoise blue dye (TBD) as model pollutant. Single doping (with Nb) and co-doping (Fe and Nb) catalyst reached complete decolorization within 2.5 hours and 3 hours. In addition, their kinetic reaction rate constants of apparent first-order model are 0.0258 min -1 and 0.0225 min -1 , respectively. The presence of Nb as traps is considered to play a crucial key in enhancing the photocatalytic activity.
For the development of automotive catalysts which may fit the condition of developing countries, ... more For the development of automotive catalysts which may fit the condition of developing countries, catalytic activity of alumina for CO oxidation was studied. It was proposed that the carbon formed in-situ acted as an active site for CO oxidation. The carbon active site was also checked by methanol oxidation on alumina which showed temperature hysteresis during consecutive heating and cooling operations. Alkali-treated Alumina did not show any indication of the temperature hysteresis. The optimal temperature for maximum carbon depostion was confirmed by thermogravimetric analysis to be 450 -500 C. which well explains the hysteresis. CeO2-AI203 showed remarkably higher activities for complete oxidation. It seems that alumina has reasonably satisfactory activity in total clean-up of exhaust gas.
Structural Stability of Ferrocement Garbage Disposal Barge
The solid waste disposal problem of Metro Manila has attained significant attention for over the ... more The solid waste disposal problem of Metro Manila has attained significant attention for over the last decade and waste generation has increased by almost 50%. Dumping, land filling, recycling, and segregation are insufficient disposal methods that compromise the well being of the environment and human health, prompting the need for a more effective method of permanent garbage disposal. A proposed solution to the given dilemma is the construction of a Ferrocement barge that would incorporate non- biodegradable and non-recyclable solid wastes in the structure. The structural integrity of a Ferrocement garbage disposal barge reinforced with bamboo and plastic mesh was evaluated by fabricating and comparing ordinary Ferrocement panels and substituted reinforcement Ferrocement panels. Two strength tests that were in accordance with ASTM were conducted on the different panel types that were fabricated: Transverse and Axial Compression. The proposed bamboo-reinforced (BR) hybrid panels were at par with the typical steel-reinforced (SR) ferrocement panels in terms of compressive strength results. However, the hybrid panels behaved poorly in terms of tests in tension. From test results, it would be plausible to use hybrid panels only as walls in the proposed barge.
Korean Journal of Chemical Engineering, Sep 1, 1998
Activity of 'alumina was tested for CO and hydrocarbon oxidation using the flow reactor system. T... more Activity of 'alumina was tested for CO and hydrocarbon oxidation using the flow reactor system. The mechanism of the CO oxidation was elucidated by isotopic tracer technique using a closed circulation system. CO oxidation was found to proceed via the formation of a carbonate type of intermediate species. Water enhances the CO oxidation and CO2 retards alumina activity. Carbon deposition was also investigated during CO oxidation on alumina. Carbon formed was found to act as an in-sire active site that promoted CO oxidation. Results obtained showed alumina to be promising for CO oxidation. Pb showed opposite effects on CO and hydrocarbon reactions. Hydrocarbon reactivity test conducted showed that methanol is the most reactive on alumina giving 100 % conversion at 500~ However, carbon deposited affected the formation of several products at this temperature. Further study on methanol oxidation using alkaline treated alumina showed better performance for auto emission control. CeO> known to have an oxygen storage capacity, was tested as an additive to alumina for methanol oxidation and propylene oxidation. Results proved that CeO2-Al203 gave much higher activity for CO oxidation, methanol oxidation, and pmpylene oxidation than alumina.
This study deals with the impact of calcination, alkalinity, and curing time parameters on the hy... more This study deals with the impact of calcination, alkalinity, and curing time parameters on the hydrothermal synthesis of zeolite A. The zeolite A sample, produced from corncob-stalkand-leaves (corn stover) ash was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), and scanning electron microscopy (SEM). The results showed that calcination, alkalinity, and curing time have significant effects on the crystallization and the morphology of zeolite A. In addition, these parameters also impacted the cation exchange capacity. Furthermore, the synthesized zeolite A was obtained using a calcination temperature of 500 • C within two hours of airflow, which is much lower than the temperatures previously reported in the literature for an agricultural waste and other waste materials. A fusion ratio of corn stover ash:NaOH of 1.0:1.5 and a curing time of nine hours were achieved. This is a major result as this curing time is much lower than those featured in other studies, which can reach up to twenty-four hours. In this paper, cubic crystal with rounded edge of zeolite A, having a cation exchange capacity of 2.439 meq Na + /g of synthesized anhydrous zeolite A, was obtained, which can be a good candidate for ion-exchange separation.
ASEAN Journal of Chemical Engineering, Jun 1, 2006
This study investigated the effect of the different initialconcentrations of polychlorinated biph... more This study investigated the effect of the different initialconcentrations of polychlorinated biphenyls (PCBs) on its degradation in water matrix using UVIHP2 and on the formation of reaction intermediates or products. Simulated PCB-contaminated water solution was subjected to irradiation with 17 W, 254 nm wavelength UV lamp in a batch tubular reactor. The ratio of oxidant to PCBs, in terms of Arodor 1260, was based on 2,800 I!L HP2 isto 40 ppm PCB. Samples were extracted from the matrix by solid-phase extraction (SPE) method using C18 cartridges with hexane and ethyl acetate as solvents. The samples were analyzed using Gas Chromatography-Electron Capture Detector System (GC-ECD) to determine the concentration of PCBs in the samples and pH was monitored every sampling time. The analysis of chloride (CI-)ion concentration in the samples was done using Argentometric titration. Determination of reaction intermediates and products was carried out with 40 ppm PCB concentration using Gas Chromatography-Mass Spectroscopy (GC-MS) system. A decrease in pH in the early stages of degradation was observed and the higher the initial concentration of PCB the greater was the drop in pH. The PCB degradation profile showed that from 1 to 40 ppm initial concentration, the degradation efficiency of UVIHP2 increased with increasing initial PCB concentration. At 80 ppm, however, it was observed that there was a decrease in the efficiency of the system. The inorganic chloride ions produced indicate that dechlorination took place in the system. GC-MS analysis verified the decrease in concentration of PCBs in the solution and showed the preferential attack of the UV/HP2 to PCBs over long chain saturated alkanes or waxes which contained the PCBs.
Evaluating Thermal Properties of Geopolymer Produced from Red Mud, Rice Husk Ash and Diatomaceous Earth
ASEAN Engineering Journal, 2015
In this paper, thermal properties of geopolymer from the mixture of red mud, rice husk ash, and d... more In this paper, thermal properties of geopolymer from the mixture of red mud, rice husk ash, and diatomaceous earth were investigated. Red mud is an industrial waste from bauxite plants which has a negative impact to the environment if not properly managed, especially for countries mining this bauxite ore. On the other hand, rice husk ash is an agricultural waste abundant in Asian countries whereas diatomaceous earth is a natural mineral locally abundant in some parts of Vietnam. In this study, red mud was mixed with rice husk ash and diatomaceous earth at high alkaline condition to synthesize geopolymer, an inorganic polymer materials produced from geopolymerization reactions forming the alumino-silicate network. For thermal specifications of the geopolymer products, thermal conductivity, the thermal expansion and thermal gravimetric (TG) values from room temperature to 950 o C are measured. For example, the coefficient of thermal conductivity at room temperature was measured around 0.5 W/m-K, the coefficient of thermal expansion around 950 o C is in range of 5.71x10 -6 K -1 to 12.42x10 –6 K –1 and TG at 950 o C is below 10%. Response surface method was also used to determine the thermal properties of geopolymer as a function of mix proportions of raw materials. The study also investigated the changes of microstructure when the geopolymer is subjected to high temperature via X-ray diffraction (XRD) and scanning electron microscopy (SEM).
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Papers by Susan Gallardo