Multiwalled carbon (C) nanotubes (CNTs) were synthesized by nebulized spray pyrolysis of xylene and ferrocene in a horizontal tube furnace at atmospheric pressure. The reaction temperature and the argon (Ar) gas flow rate were kept constant at 1200 degrees C and 3.5 l/min, respectively, while the hydrogen (H-2) gas flow rate was varied. The as-synthesized CNT films were then purified through peroxide and acid treatment. The samples were characterized with Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry-differential thermal analysis (TG-DTA) and nitrogen (N-2) Brunauer-Emmett-Teller (BET) analysis. Raman measurements revealed a wide D-band and a comparatively narrow G-band, indicating relatively good graphitization of the CNTs, which is supported by TEM measurements and the I-D/I-G ratio of 0.072. TEM measurements exhibited multiple semicrystalline concentric CNTs with an outer diameter of around 33 nm. From radial breathing mode measurements, the diameter of the innermost tube was estimated to be 0.9 nm, consistent with TEM measurements. TG-DTA showed that 47% of the purified CNT sample was amorphous CNTs, 39% was composed of CNTs, 6% was the oxidized catalyst and the remaining 8% was amorphous carbon. Nitrogen BET analysis showed the surface area of the CNT to be 321.5m(2)/g, corresponding to a high-porosity CNT sample consistent with SEM measurements.

We synthesized zinc oxide-reduced graphene oxide (ZnO-rGO) composites using a one-pot chemical deposition method at room temperature. Zinc powder and graphene oxide (GO) of different mass ratios (1 : 1, 1 : 2, 1 : 5, 1 : 10, and 1 : 20 GO to Zn) were used as precursors in a mildly alkaline solution. UV-Vis spectroscopy was used to study the photocatalytic efficiency of the samples through the photodegradation of methylene blue (MB). UV-Vis measurements show the fast decomposition of methylene blue under UV light illumination with the best degradation efficiency of 97.7% within one hour, achieved with sample ZG2 (1 GO : 2 Zn mass ratio). The corresponding degradation rate was k ZG2 = 0.1253 min −1 , which is at least 5.5 times better than other existing works using hydrothermal methods. We argue that the excellent photodegradation of MB by ZG2 is due to the efficient charge separation brought about by the electronic interaction of the rGO with the ZnO and the formation of a Zn-O-C bond, as supported by XRD and Raman spectroscopy measurements.

Particle size of the as-deposited carbon spheres (CSs) from plant-derived oil precursor was modified through the addition of a corona discharge ionizer as an attachment to the conventional atmospheric chemical vapor deposition (CVD) setup. Influences of synthesis parameters such as temperature, solvent-oil concentration, and the presence of ionization on the particle size distribution, graphitization, and conductivity of the CSs were also investigated. The addition of pyridine as a solvent to the Calophyllum inophyllum (CI) oil improved precursor atomization, breaking down the viscous oil into finer vapor intermediates and consequently, the process of decomposition. Measured particle size distribution from scanning electron microscope (SEM) and atomic force microscope (AFM) images show a decrease in mean particle diameter, from > 180 nm without ionization to < 100 nm with ionization. This relates mostly to the decrease in Brownian motion of particles within the system during deposition due to the presence of opposing electrostatic forces brought about by particles having the same electric charge. TEM images confirm the presence of concentrically-wrapped layers of carbon at the surface. Raman spectra also show the presence of graphitic layering within the carbon spheres, with two primary peaks located at 1350 cm(-1) and 1580 cm(-1) pertaining to both the D and the G bands of all in-plane bonded carbon atoms, respectively. Ionized samples have higher I-D/I-G ratios, suggesting a short order graphitization compared to non-ionized samples. However, samples prepared at higher temperatures show a slight improvement in the level of graphitization with a decreased I-D/I-G ratio. Current-voltage measurements from conductive AFM have a general ohmic behavior for all non-powdered CSs. Ionized samples show lower sheet resistance (23.13-160.72 k Omega) possibly due to reduced particle size. The nanometer size may have resulted to lower void fraction, allowing efficient electron flow. This study emphasizes nanometer size control of conducting carbon spheres from sustainable resources.

Calophyllum inophyllum (CI) oil was used as precursor source material in carbon nanomaterial synthesis. CI is a non-edible and native plant species in the Philippines, which makes production of seeds and kernel sustainable. An atmospheric pressure chemical vapor deposition system was designed and built for the synthesis. Different carbon-based nanostructures were synthesized by varying the Argon gas flow rates (3.5-5 liter/min) and temperatures (1000-1200 degrees C). Crystalline multiwalled nanofibers and iron carbide-encapsulated nanocapsules were formed at 1000 degrees C and a gas flow rate of 5 liter/ min. On the other hand, oils synthesized at 1100-1200 degrees C produced amorphous film-like carbon materials. The different morphologies reflect the influence of the gas flow rate on the dilution and atomization of the oil and its decomposition at various temperatures used. Raman spectroscopy and surface potential measurements indicate the potential applications of these nanofibers for hydrogen storage and semiconducting devices.

The addition of polyaniline emeraldine base dissolved in N-methyl-2-pyrrolidone (PAni/NMP) on fullerene C-60 whiskers (FW) by direct-mixing technique resulted to the formation of a hybrid material herein called FW/PAni hybrid. The FW/PAni hybrid has a tubular structure with pleated surface texture. It is thinly coated with PAni and has a higher surface area relative to pristine FW and PAni. Beneath the amorphous outer covering, the hybrid shows a crystalline structure as shown by high resolution TEM and selected area electron diffraction. Charge transfer (CT) interaction from electron-rich PAni to electron deficient FW may have resulted to the physical chain entanglement of PAni to FW. The tubular structure of the hybrid is likely caused by the lone pair electrons present in both NMP and PAni causing dissolution inside the whisker. The FW/PAni hybrid having a large surface area and narrow pore size distribution has potential use as hydrogen adsorbent for fuel cell applications, catalysts, and templates for nanofabrication.

This study investigates the calcareous nannofossil assemblage and composition of 62 field samples collected from a calcareous sedimentary sequence exposed in Mamburao, Occidental Mindoro, Philippines. The sequence consisting of foraminifera-rich, alternating beds of mudstones and fine- to medium-grained sandstones was subjected to stratigraphic logging and detailed calcareous nannofossil analysis. The nannofossils were used to interpret the biostratigraphic assignment of the sequence relative to the identified formations in the study area. Index calcareous nannofossil species reveal a Late Pliocene to Early Pleistocene age (~1.67 to 4.13 Ma) of the sequence, which suggests it was formed from continuous sedimentation after the Miocene collision of the Palawan-Mindoro Block with the Philippine Mobile Belt. Based on its lithologic description and age, the sequence represents the northwest extension of the Balanga Formation, a sedimentary unit reported to be extensively distributed in southeast Mindoro.

The removal of Ni(II) using chitosan-coated bentonite (CHB) from aqueous solutions was investigated under dynamic conditions. The CHB adsorbent was characterized using BET and thermogravimetric analysis. The effect of various experimental parameters such as bed depth (1.3-4.3 -1 -1 cm), flow rate (0.2-0.6 mL min ), and initial concentration (500-1500 mg L ) on the service time of the CHB bed and shape of the breakthrough curve was examined. The breakthrough curves become steeper and the bed service time becomes shorter with decreasing bed depth, and increasing flow rate -1 and initial concentration. At bed depth of 4.3 cm, flow rate of 0.2 mL min , and initial concentration -1 -1 of 500 mg L , the maximum uptake capacity at breakthrough and exhaustion of 15 and 17 mg g , respectively, as well as the highest total Ni(II) removal of about 88% was achieved. The bed depth service time model was utilized to predict breakthrough times at various flow rate and initial concentrations. A good agreement is observed between the theoretical and experimental values at time of breakthrough under low flow rates and low initial concentration. But a slight deviation could be seen between the predicted and experimental breakthrough times at higher flow rate and initial concentration.

The potential of using ophiolites for CCS has been pointed out before, but no case study has been conducted for the Philippines. Here, the potential for CCS in both ophiolites in general and ophiolites in the Philippines in particular is examined and discussed. Specific drawbacks of using ophiolites as a CO2 sink are presented for the first time, using information from natural analogue studies in the Philippines and Jordan.

Bentonite is one of the safety-critical components of the engineered barrier system for the disposal concepts developed for many types of radioactive waste. However, bentonite — especially the swelling clay component that contributes to its essential barrier functions — is unstable at high pH. To date, results from laboratory tests on bentonite degradation have been ambiguous as the reaction rates are so slow as to be difficult to observe. As such, a key goal in this project is to examine the reaction of natural bentonites in contact with natural hyperalkaline groundwaters to determine if any long-term alteration of the bentonite occurs. Ophiolites have been identified as sources of hyperalkaline groundwaters that can be considered natural analogues of the leachates produced by some cementitious materials in repositories for radioactive waste. At the Zambales ophiolite in the Philippines, widespread active serpentinisation results in hyperalkaline groundwaters with measured pH values of up to 11.7, falling into the range typical of low-alkali cement porewaters. These cements are presently being developed worldwide to minimise the geochemical perturbations which are expected to result from the use of OPC-based concretes (see Kamei et al., this conference, for details). In particular, it is hoped that the lower pH of the low-alkali cement leachates will reduce, or even avoid entirely, the potential degradation of the bentonite buffer which is expected at the higher pH levels (12.5 and above) common to OPC-based concretes. During recent field campaigns at two sites in the Zambales ophiolite (Mangatarem and Bigbiga), samples of bentonite and the associated hyperalkaline groundwaters have been collected by drilling and trenching. At Mangatarem, qualitative data from a ‘fossil’ (i.e. no groundwater is currently present) reaction zone indicates some alteration of the bentonite to zeolite, serpentine and CSH phases. Preliminary reaction path modelling suggests that the zeolites could have been produced as a product of smectite reaction in the hyperalkaline groundwaters. Although not included in this calculation to date, the CSH phases identified are completely consistent with reaction of clays with hyperalkaline groundwaters, as seen at other sites worldwide. At the Bigbiga site, an active hyperalkaline groundwater/bentonite reaction zone (at the base of the bentonite deposit) has recently been identified and a drilling campaign is planned for late autumn 2010.

Nanostructured film deposit of ammonia (NH₃) sensitive ZnO and ZnOCuO composites were fabricated on graphite electrode via electrophoretic deposition (EPD). The fabrication was carried out at varying deposition potential and constant deposition time at room temperature. The average particle size deposited at 500V for ZnO and ZnO-CuO were 241nm and 260nm; whereas at 750V the average particle size is 195nm and 276nm, respectively. SEM micrographs showed nanocrystalline ZnO and smooth amorphous CuO film deposits. The sensing properties of the deposits were tested using Wheatstone bridge circuit. Deposits with high degree of porosity exhibit high sensitivity. Addition of CuO resulted to a decrease in gas sensitivity. The surface structure of the deposits dictates the sensitivity of the material.