This study compares the adsorption capacity of modified CNTs using acid and heat treatment. The CNTs were synthesized from acetone and ethanol as carbon sources, using floating catalyst chemical vapor deposition (FC-CVD) method. energy-dispersive X-ray spectroscopy (EDX) and Boehm method revealed the existence of oxygen functional group on the surface of CNTs. Heat modification increases the adsorption capacity of as-synthesized CNTs for methylene blue (MB) and phenol by approximately 76% and 50%, respectively. However, acid modification decreases the adsorption capacity. The equilibrium adsorption data fitted the Redlich-Peterson isotherm. For the adsorption kinetic study, the experimental data obeyed the pseudo-second-order model. Both modifications methods reduced the surface area and pore volume. The studies show that the adsorption of MB and phenol onto modified CNTs is much more influenced by their surface functional group than their surface area and pore volume.
Ceramic foams, a porous material with a gyroid structures, are becoming highly demanded for various applications such as heat insulation, bone implantation and filtration, because of their unique properties such as high specific surface area, high porosity and low heat transfer rate. In this study, the development of ceramic foam utilised white clay with a combination of precipitated calcium carbonate (PCC). The ceramic foam was successfully developed using this combination after the sample was sintered at 1250 °C for 2 hours holding time. The various compositions of PCC (10.0, 12.5, 15.0, 17.5, 20.0, 22.5 and 25.0 wt.%) affected the chemical composition and compressive strength of the ceramic foam. The chemical composition of ceramic foam was analysed by using X -ray fluorescence (XRF) and the result indicated that the PCC was successfully transformed into calcium oxide (CaO) after the sintering process. The mineralogical composition of the ceramic foam was evaluated using X-ray diffraction (XRD) and has shown the presence of mullite (3Al2O3.2SiO2), gehlenite (Ca2Al2SiO7) and anorthite (2CaAl2Si2O8) after the sintering process. The scanning electron microscope (SEM) analysis showed that the presence of porosity on the strut of the ceramic foam. Meanwhile, the compressive strength of the ceramic foam increased from 0.03 to 1.31 MPa, which is directly proportional to the increased amount of PCC.
Metals are increasingly used in engineering due to their high specific strength. However, some of pure metals do not posses good corrosion resistance. Therefore carbon nanomaterials (CNMs) has been studied to overwhelm the corrosion existed on the metal’s surface. CNMs are synthesized directly on various metal substrates by Chemical Vapor Deposition (CVD) technique without addition of any external catalyst, in reactor at temperature of 800°C. Argon with a flow rate of 200ml/min was used as a carrier gas and acetone as a carbon source. In this study, two different metals were used as metal substrate: mild steel and stainless steel 316. The morphology, existence of CNTs and elemental analysis of the CNMs on metal substrate are evaluated using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Energy Dispersive X-ray (EDX), respectively. It was proven that the different element composition of metal substrate influenced the size and morphology of CNMs. The most suitable metal to grow CNTs was found to be stainless steel.
This work is a preliminary study to investigate the growth of carbon nanofibres (CNFs) on monolayer graphene. The growth of CNFs on graphene has been performed by chemical vapour deposition (CVD) using ferrocene as the catalyst precursor and acetone as the carbon source. Ferrocene in acetone is introduced to the system via spray coating onto the substrate. Graphene film used in this study is grown on nickel (Ni) thin film, which is confirmed to be monolayer. Aligned CNTs are unintentionally obtained, however only at the graphene/Ni thin film edges.
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