Papers by Keyword: Porous Carbon

Abstract: Nowadays, many individuals utilize the 5G network, which can give detrimental effects due to electromagnetic interference (EMI). EMI may harm not only high-tech electronic devices but also human health. In this study, the porous carbon was synthesized from palm kernel shell (PKS) via hydrothermal treatment at varying temperatures (160 °C, 180 °C, and 200 °C) followed by carbonization, and comprehensively characterized to understand its structural, chemical, and electromagnetic properties. X-ray diffraction (XRD) revealed broad (002) and (100) peaks across all samples, indicating amorphous graphitic carbon with limited crystallinity. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of O–H, C–H, and C=C functional group. As the synthesis temperature increased, aromatic and graphitic characteristics became more pronounced, with 180 °C exhibiting a significant rise in C–H peak intensity. This suggests that 180 °C is an optimal carbonization temperature, promoting the formation or preservation of stable aliphatic structures without excessive degradation. Surface area analysis using the BET method showed that the sample treated at 180 °C exhibited the highest surface area (547.4 m²/g), suggesting optimal porosity formation. Scanning electron microscopy (SEM) supported this finding, showing a fragmented and open morphology at 180 °C, in contrast to denser, spherical agglomerates observed at 200 °C. Due to its characteristics, the 180 °C sample was selected for electromagnetic characterization. S-parameter measurements at X-band frequency for epoxy composites filled with porous carbon revealed that increasing filler content led to reduced transmission coefficient, indicating enhanced electromagnetic wave attenuation. These improvements are attributed to increased dielectric losses and interfacial polarization facilitated by the highly porous carbon network. In conclusion, the study highlights the significance of hydrothermal synthesis temperature in tuning the structure and electromagnetic performance of biomass-derived porous carbon.

Abstract: The present research focuses on the development of highly efficient and lightweight electromagnetic wave (EMW) absorbers to address the growing issue of electromagnetic pollution. We investigate the use of carbon derived from biomass, specifically durian husks, to create carbon-based microwave absorbers with enhanced performance. A two-step process involving carbonization followed by potassium hydroxide (KOH) activation was employed to synthesize porous carbon materials. The microwave absorption properties were then analyzed using a vector network analyzer across a frequency range from 2 to 18 GHz, with a focus on key parameters such as reflection loss and complex permittivity. The sample, which was 2.0 mm thick and had 15% carbon nanomaterials mixed in with paraffin wax, had an optimal reflection loss of -30.8 dB at 12.8 GHz with an effective absorption bandwidth of 9.0 GHz, highlighting its strong electromagnetic wave absorption performance. The porous structure and large specific surface area significantly contributed to the material’s ability to absorb electromagnetic radiation. These findings highlight the potential of durian husk-derived carbon material as a highly effective and lightweight EMW absorber for practical applications.

Abstract: A study was conducted to investigate the effect of activator types KOH, ZnCl₂, and H₃PO₄ on the specific surface area of porous carbon and its performance as a Li-S battery. Porous carbon was synthesized from candlenut shells through a carbonization process at 700 °C using three types of activator solutions with a concentration of 0.36 M. The porous carbon activated with KOH achieved the best results, with a specific surface area of 681 m²g^-1. The porous carbon candlenut shell-sulfur (PCCS-S) composite was obtained by the solid-state reaction method in a ratio of 1:2.5 w% and heat-treated at 155 °C to form the PCCS-S composite. The PCCS-S composite was then made into a slurry and coated onto Al-foil to obtain a layer of electrodes with a thickness of 200 µm. The PCCS-S cathode was then assembled into a coin battery with lithium metal as the anode and an electrolyte of 1.0 M LiTFSi solution dissolved in 1,3-dioxolane (DOL) and 1,2-dimethoxyethane (DME) (v/v, 1:1). Charge-discharge characterization was carried out at a charge rate of 1 C for 50 cycles. Characterization shows that the performance of the PCCS-S KOH composite cathode Li-S battery is stable at a specific capacity of 324 mAhg^-1 after the first 10 cycles, with an average Coulombic efficiency of around 86.8 %.

Abstract: Porous carbon is one of the promising electrode materials for supercapacitors due to its unique and engineerable microstructural properties. The study of the synthesis of porous carbon from waste biomass is very important due to the abundance of natural resources, low cost production and contribute to solving environmental problems. In this study, porous carbons derived from candlnut shell with various type of activator was studied the chemical structural, morphological and electrochemical properties then evaluated as electrodes for supercapacitor. We have been successfully synthesized of porous carbon from candlenut shells using three steps of the process, i.e.: carboni-zation, activation and calcination. Carbonization was carried out at 700°C in a furnace using a closed crucible to minimize the oxygen. The chemical activation conducted using three types of activators, i.e. ZnCl₂, H₃PO₄ and KOH then calcination process by heated at 800°C for 1 h under Ar flow. The results of the Fourier-transform infrared (FTIR) analysis show that the carbonization process increases the content of aromatic C=C functional groups and reduce the OH, C-H, C-O and C=O functional groups. The carbonization process has also increased the electrical conductivity of the sample around 0.8525 S/m. The results of Scanning Electron Microscope (SEM) images can be observed that the activation process of carbon has formed which was indicated by the appearance of many pores on the surface area of carbon. N₂ adsorption/desorption isotherms (Brunauer–Emmett–Teller (BET)) characterization was indicated that the porous carbon is dominated by mesoporous with a pore size around 2-50 nm. BET characterization also can be determined the surface area of porous carbon around 477 m²/g for ZnCl₂, 636 m²/g for H₃PO₄, and 681 m²/g for KOH. This synthesized materials are further employed in a symmetric supercapacitor using simple glass cell. The best performance of supercapacitor achieved by KOH porous carbons with 16.30 F/g of specific capacitance, 2.26 Wh/kg of energy density and 1038 W/kg of power density.

Abstract: This paper attempts to evaluate the use of composite of polyaniline (PANI)/palm kernel shell-derived porous carbon (C-PKS) as alternative materials for supercapacitor electrodes. The preparation of PANI/C-PKS composites was carried out using an in-situ polymerization method. After the composite was formed, the structures and morphologies were characterized using an N2-sorption analyzer, SEM - EDX, and TGA. As for the performance of supercapacitor electrodes, the composite was tested using a three-electrode system. Structural and morphological characterization results showed that PANI was successfully deposited in C-PKS. The amount of PANI deposited in C-PKS was ca. 7.5%, obtained from TGA analysis. Meanwhile, the capacitance performance test results showed that the PANI/C-PKS composite featured a specific capacitance of ca. 116 F/g. There was an increase in specific capacitance compared to the blank material (C-PKS only) which showed only 94 F/g.

Abstract: Research on the mechanical thermal stability of micro-porous carbon-based micro composites with marine paint matrices has been carried out. Microporous carbon has the property of absorbing radar waves so it is very interesting to research and develop into a microwave shielding material synthesized from coconut shell (cocoa nucifera) by carbonization process at 600°C for 45 minutes. The molecular structure and phases of micro porous carbon were characterized using Fourier Transform Infrared (FTIR) and X-Ray Diffraction (XRD) with the results confirmed of micro carbon with reduced graphene oxide (rGO) phase. Furthermore, micro-composites made from porous micro carbon with marine paint as a binder were made using the wet mixing-casting method. Mechanical thermal testing was carried out by means of a shear test at a temperature range of 30 – 70°C using a Dynamics Mechanical Analysis (DMA) tool. The test results showed that the value of the storage modulus of porous micro carbon composites was 1.653 MPa, 10.196 MPa, 13.068 MPa, 118.567 MPa, respectively. The value of the composite storage modulus increases with increasing concentration of porous micro carbon with an optimum value of mechanical thermal stability at a composition of 70:30 %wt. The results of mechanical thermal testing showed that porous micro carbon with rGO phase from coconut shells has the potential to be used as an anti-radar shielding material. 068 MPa, 118.567 MPa. The value of the composite storage modulus increases with increasing concentration of porous micro carbon with an optimum value of mechanical thermal stability at a composition of 70:30 %wt. The results of mechanical thermal testing showed that porous micro carbon with rGO phase from coconut shells has the potential to be used as an anti-radar shielding material. 068 MPa, 118.567 MPa. The value of the composite storage modulus increases with increasing concentration of porous micro carbon with an optimum value of mechanical thermal stability at a composition of 70:30 %wt. The results of mechanical thermal testing showed that porous micro carbon with rGO phase from coconut shells has the potential to be used as an anti-radar shielding material.

Abstract: Ibuprofen is a nonsteroidal anti-inflammatory drug classified as one of the emerging contaminants from the pharmaceuticals group. Ibuprofen detected in the environment indicates that wastewater treatment facilities have a limited ability to remove this substance. Residual ibuprofen that accumulates continuously can harm ecosystems in the waters and indirectly affect human health. Adsorption using porous material is a method that can reduce the amount of ibuprofen in wastewater. This research synthesized porous carbon by pyrolysis of phenolic polymer. The resulting material was then characterized using an N₂-sorption analyzer, SEM, and XRD. After being characterized, the material was used to adsorb ibuprofen at various concentrations. SEM characterization showed that carbon had voids or channels for adsorbing ibuprofen molecules. N₂-sorption analyzer delivered that the polymer-derived carbon has a specific surface area of about ​​594 m² g^-1. Based on the adsorption test result, the porous carbon could adsorb the ibuprofen molecules in the simulated wastewater well and followed the Freundlich equilibrium model.

Abstract: Biogas is considered as a promising renewable energy. Therefore, in order to achieve a high quality of energy, biogas upgrading steps at the upstream of its final utilization is required. One of the most important steps is CO₂ removal which has a significant impact on improving the biogas properties for energy applications. In this study, separation of CO₂ from biogas (consisting of CO₂/CH₄: 63/37 vol%) in a packed-bed of Palm Kernel Shell (PKS)-based porous carbon was performed. The separation-regeneration cycle was carried out at atmospheric pressure, isothermal conditions (30 °C), and different feed flow rates (25, 50, and 100 mL.min^-1). The study showed that CO₂ was successfully separated from biogas which produced CH₄ ­­­­­with high purity (>98 vol%). On the other hand, the separation behavior of gases on porous carbon was influenced by feed flowrate where the high separation capacity was achieved at low feed flowrate.

Abstract: This research was conducted to study changes in functional groups after oxidation of porous carbon synthesized from palm kernel shell and their effects on the performance of material for an electric double-layer capacitor (EDLC). Porous carbon was prepared by pyrolysis of palm kernel shell at a temperature of 800 °C and steam activation. Surface modification was conducted by oxidation porous carbon using hydrogen peroxide (H₂O₂). Properties of material were characterized using N₂-sorption analysis, scanning electron microscopy (SEM), and Fourier transforms infrared spectroscopy (FTIR) analysis. Measurement of biomass-based porous carbon as an electrode for EDLC was carried out using cyclic voltammetry and galvanostatic charge-discharge methods. The test was conducted using a three-electrode system, with carbon as the working electrode, Ag/AgCl as the reference electrode, Pt as the auxiliary electrode. The electrolyte used was 1 M H₂SO₄ solution. The results showed that oxidation of porous carbon using H₂O₂ lowers the specific surface area but increases oxygen functional groups in the carbon surface. The results on testing the performance of EDLC, surface-modified carbon showed better EDLC performance of 5-7 times higher compared to carbon before oxidation.

Abstract: The goal of this study is to investigate the efficacy of potassium permanganate (KMnO₄) confined in porous carbon for hydrogen sulfide removal. As porous support, carbon was prepared by carbonization process of abundantly biomass source of palm kernel shell (named KATKS). The surface of porous carbon was first modified using hydrogen peroxide oxidation. The confinement process was carried out by an impregnation process. The KMnO₄ contents in porous carbon were varied i.e. 5%, 10%, and 20% w/w (KMnO₄-%/KATKS-Ox). Materials were characterized by N₂-sorption analysis and SEM-EDX. The results showed that KATKS possesses a high specific surface area of ca. 700 m²/g. Due to the impregnation of KMnO₄, the specific surface area of KMnO₄-%/KATKS-Ox decreased to ca. 450 m²/g. SEM-EDX revealed a successful confinement process in which elements of K, Mn, and O were displayed and dispersed on the carbon surface. In the hydrogen sulfide (H₂S) oxidation testing, KMnO₄-20%/KATKS-Ox showed the highest performance of H₂S removal compared to other materials due to the high amount of KMnO₄. KMnO₄-20%/KATKS-Ox could reduce until 98.7% of H₂S. This is remarkably higher than only using bulk KMnO₄ (without confinement) which showed activity of ca. 70% reduction.