Activated carbons are regularly used the treatment of dye wastewater. They can be produced from various organics materials having high level of carbon content. In this study, a novel Pinang frond activated carbon (PFAC) was produced at various CO₂ flow rates in the range of 150-600 mL/min at activation temperature of 800°C for 3 hours. The optimum PFAC sample is found on CO₂ flow rate of 300 mL/min which gives the highest BET surface area and pore volume of 958 m²/g and 0.5469 mL/g, respectively. This sample shows well-developed pore structure with high fixed carbon content of 79.74%. The removal of methylene blue (MB) by 95.8% for initial MB concentration of 50 mg/L and 72.6% for 500 mg/L is achieved via this sample. The PFAC is thus identified to be a suitable adsorbent for removing MB from aqueous solution.
Activated carbons can be produced from different precursors, including coals of different ranks, and lignocellulosic materials, by physical or chemical activation processes. The objective of this paper is to characterize oil-palm shells, as a biomass byproduct from palm-oil mills which were converted into activated carbons by nitrogen pyrolysis followed by CO2 activation. The effects of no holding peak pyrolysis temperature on the physical characteristics of the activated carbons are studied. The BET surface area of the activated carbon is investigated using N2 adsorption at 77 K with selected temperatures of 500, 600, and 700°C. These pyrolysis conditions for preparing the activated carbons are found to yield higher BET surface area at a pyrolysis temperature of 700°C compared to selected commercial activated carbon. The activated carbons thus result in well-developed porosities and predominantly microporosities. By using this activation method, significant improvement can be obtained in the surface characteristics of the activated carbons. Thus this study shows that the preparation time can be shortened while better results of activated carbon can be produced.
Piping system is the main structure in many industrial applications, especially for large industry relating with processing and transporting fluids, such as oil and gas industries. The fluid-induced vibration is often the cause of structural fatigue in pipes and therefore piping vibration need to be closely monitored. In case of high piping vibration, knowledge of the natural frequency of a pipe section is crucial for an engineer to propose the right troubleshoot action, either for a temporary or even for a long-term solution for the piping vibration. Therefore, prediction of the pipe natural frequency using a simple formulae is thus of interest, without dealing with complex numerical simulation using a commercial software which consumes cost and time. In this paper, the vibration mode shapes of various possible geometries of pipes in practice were simulated in ANSYS and the simulated natural frequency is related to a natural frequency of an Euler-Bernoulli beam using a correction factor for each corresponding piping geometry. This paper extends the previous work by allowing the boundary conditions of the pipe ends to be simply supported, in addition to the clamped edges. In this way, the frequency factor charts are presented in the range of possible correction factor values to accommodate the real conditions of pipe arrangement in practical application. An experiment from a case study to verify the proposed method is also presented.