Papers by Keyword: Activated Carbon

Abstract: This study investigates the removal of radioactive cesium-137 (Cs-137) from wastewater using activated carbon derived from cassava rhizome (CRAC), composited with copper hexacyanoferrate (CuHCF) through three synthesis methods including hydrothermal (HTM), ultrasonic-assisted (US), and mechanical stirring (STIR). The objective was to enhance the availability of active adsorption sites for improved Cs-137 capture. Fourier-transform infrared (FTIR) spectroscopy revealed the formation of carboxylate ion groups (-COO^-) in the CRAC/CuHCF composites synthesized via the hydrothermal method, indicating deprotonation of carboxylic groups (-COOH) during synthesis. This transformation is believed to facilitate Cs⁺ ion binding. X-ray diffraction (XRD) analysis confirmed the presence of a face-centered cubic structure in the composite, which provides structural vacancies conducive to Cs⁺ diffusion. These findings suggest a dual adsorption mechanism involving surface complexation and lattice incorporation. BET analysis revealed that CRAC composites exhibited significantly enhanced surface area and porosity, with the HTM method providing uniform carbon dispersion and the smallest pore diameter (5.46 nm), whereas US cavitation yielded the highest pore volume (0.17 cm³/g). Batch adsorption experiments demonstrated that CRAC/CuHCF (HTM) composites achieved the highest Cs-137 removal efficiency (98.90%) and adsorption capacity (6.15 × 10⁻⁷ mg/g), outperforming composites synthesized via US and STIR methods, as well as pure CuHCF and CRAC alone. Kinetic modeling indicated that the adsorption process followed a pseudo-second-order model, suggesting chemisorption as the dominant mechanism. Furthermore, the adsorption isotherm was best described by the Freundlich model, implying multilayer adsorption on heterogeneous surfaces.

Abstract: This paper discussed various types of pore formers that have previously been applied as porosity enhancers in the NiO YSZ-based planar SOFC anode since porosity plays an important role to easily diffuse the fuel, thus increasing the triple-phase boundary area and electrochemical performance. Therefore, this study emphasized reviewing recent experiments to find out more effective pore formers by making a comparison between natural (rice starch), polymer-based (PMMA), and carbon-based materials such as graphite. It has been found that rice starch at 7 vol.% gives 10.05% porosity at 1000 °C while activated carbon graphite gives only 4.25%. PMMA shows the highest porosity of 41% at 30 vol.% at 250 °C with almost no residue left behind as proven via TGA analysis which showed only about 0.7%. These findings highlight not only the benefits but also the compromises of each approach, whether in terms of residue formation, mechanical stability, or processing cost. The review further suggests that hybrid strategies, which combine different poreformers, could offer a more balanced route toward improved microstructures. Finally, future directions are outlined, with emphasis on nanostructured agents, scalable fabrication methods, and techno-economic considerations to support the commercial adoption of SOFC technology.

Abstract: In this study, the vegetable waste-derived paper was developed from vegetable waste-derived fiber and Mahachanok mango seed-derived activated carbon to extend the shelf life of Golden Nam Dok Mai mangoes. Vegetable waste was subjected to alkaline processing using sodium hydroxide to extract plant-based fibers, which were then formed into paper sheets. Activated carbon, derived from Mahachanok mango seeds by carbonization at 450°C and activated by potassium permanganate (KMnO₄), was incorporated into the vegetable waste-derived paper to enhance ethylene adsorption efficiency. Three formulations of ripening delay paper were prepared: paper without activated carbon, paper containing 10 g of activated carbon, and paper containing 20 g of activated carbon. The physical properties of the papers were evaluated in terms of tensile strength and water drop absorption. The vegetable waste-derived paper incorporated with 20 g activated carbon showed the highest performance among the developed papers (1.20 ± 0.24 MPa and 0.74 seconds, respectively). Application tests on Golden Nam Dok Mai mangoes showed that the 10 g activated carbon formulation was the most effective in preserving flesh color, maintaining firmness, and balancing total soluble solids (TSS) and titratable acidity (TA), indicating a delayed ripening process. Therefore, ripening delay paper synthesized from vegetable fiber and supplemented with 10 g of activated carbon per 1 kg of fruit was proven to effectively prolong mango shelf life by up to 3 days, demonstrating its potential as a biodegradable solution for postharvest quality preservation.

Abstract: Preparation of activated carbon from juvenile durian fruit by activation with KMnO₄ for methylene blue adsorption was studied. The juvenile durian fruit was pyrolyzed at temperatures of 400, 450, 500, 550, and 600 °C and activated with KMnO₄. The results demonstrated that the carbonization at 600 °C yielded the highest iodine number of 298.30 mg_iodine/g_biochar. Subsequently, the methylene blue adsorption was investigated using a Box-Behnken designed batch experiment. The experimental design included three variables at three levels: adsorbent dosage (g), initial methylene blue concentration (mg/L), and adsorption time (min). The optimum conditions for methylene blue adsorption efficiency reached approximately 99.9% at an adsorbent dosage of 0.55 g, an initial methylene blue concentration of 10 mg/L, and an adsorption time of 90 min.

Abstract: The growing energy crisis and environmental challenges have spurred the development of sustainable energy storage solutions. This study synthesizes 3D porous Orange Peel-Lignin activated carbon (OPLAC) from orange peel waste and lignin using a two-step pyrolysis process with KOH activation. The OPLAC was combined with styrene-isoprene-styrene (SIS) and SUPER P conductive carbon black to create stretchable electrode composites with varying compositions (70:20:10, 60:30:10, and 50:40:10). Mechanical testing revealed that increasing the SIS content improved stretchability, with the 50:40:10 composition achieving 300% strain and retaining 95% durability after 100 cycles. However, higher SIS content reduced electrical conductivity, with the 70:20:10 composition showing the highest conductivity (12 S/cm) and the 50:40:10 the lowest (7 S/cm). The 60:30:10 composition offered a balance between flexibility and conductivity. These results demonstrate the potential of biomass-derived activated carbon for sustainable, high-performance supercapacitor electrodes, particularly for flexible electronics and wearable devices, while highlighting the valorization of agricultural and industrial waste in energy storage applications. Keywords: Stretchable electrode, activated carbon, orange peel waste, Lignin, flexible electronics

Abstract: The aim of this research is to obtain activated carbon from the solid residue generated in the pyrolysis process of used tires, using microwave technology for its activation. In the first phase, the tires were subjected to thermal pyrolysis at 575°C to obtain a carbonaceous residue (CR). This residue was then activated using potassium hydroxide (KOH) in a 1:3 ratio and exposed to a conventional microwave oven at a power of 700 W for 3 minutes without pauses, obtaining activated carbon (AC) as a result. To evaluate the adsorption capacity, tests were conducted with both carbons (CR and AC) using three concentrations of carbon, with a contact time of 300 minutes and agitation at 400 RPM. The results showed that CR achieved a maximum adsorption of 57.13% at a concentration of 0.2 g, while AC exhibited values greater than 90%. It is concluded that microwave activation is an effective and cost-efficient process to convert the carbonaceous residue from used tire pyrolysis into an adsorbent material with high arsenic removal capacity.

Abstract: Hydrogen, a zero-carbon energy source with high energy density, is widely used in Proton Exchange Membrane Fuel Cells (PEMFC), where Membrane Electrode Assembly (MEA) plays an important role. This study examines the fabrication of MEAs using the Catalyst Coated Membrane (CCM) technique by airbrush spray and ultrasonic spray methods, using Pt/C catalysts on activated carbon from kepok banana peel (soft carbon) and carbon nanotubes (CNT). Activated carbon soaked with 1M NaOH for 3 hours showed a surface area of 163.075 m²/g, exceeding that of CNTs (101.466 m²/g). The Pt/C catalyst with 1M3H-1 configuration achieved the highest Pt content (52.99 wt%). The ultrasonic spray ensured an even distribution of the catalyst, with a power density of 0.167 mW/cm² (1M3H-1) achieved faster. Although the airbrush spray reaches 0.889 mW/cm² (CNT1), the time required is longer, making the ultrasonic spray more efficient.

Abstract: Water pollution causes about 1.4 million deaths annually, and in Nigeria, especially in rural areas and the Niger Delta, millions lack access to clean water due to crude oil contamination. This study investigates using carbonized Flamboyant (Delonix regia) pods as a sustainable, low-cost adsorbent for removing petroleum hydrocarbons from contaminated water, promoting agricultural waste valorization and pollution reduction. Water samples collected from Obiakpor in Port Harcourt, Nigeria, were found to contain 75.22 mg/L of total petroleum hydrocarbons (TPH) and were subsequently used to evaluate the efficiency of the prepared adsorbent. Activated carbon was prepared by washing, drying, carbonizing the pods at 550 °C, chemically activating with KOH, neutralizing, then drying and sieving for uniformity. Carbonization yielded 30.2%, with proximate analysis showing low moisture (1.86%), moderate ash (4.94%), and high volatile matter (77.81%), favoring thermal stability and pore formation. Scanning Electron Microscopy (SEM) and Brunauer–Emmett–Teller (BET) revealed a highly porous structure with an average pore diameter of 20 μm and a large surface area of 226.4 m²/g. X-ray Diffraction (XRD) confirmed a semi-crystalline structure dominated by graphite (36 wt.%) and silicate minerals, enhancing mechanical strength and π–π interactions. Thermogravimetric Analysis (TGA showed that thermal stability was maintained between 300–500°C. Adsorption tests showed TPH removal increased with adsorbent dosage up to 0.2 g, reaching equilibrium afterward. The Freundlich isotherm best described the adsorption (R² = 0.9104), indicating multilayer adsorption on a heterogeneous surface, supported by high constants (K_f = 166.36; n = 2.35). Kinetic studies indicated rapid adsorption within 25 minutes, fitting the pseudo second order model (R² = 0.9575). These findings confirm that carbonized Flamboyant tree pods (FTP) are effective, renewable, and thermally stable adsorbents for petroleum-contaminated water treatment.

Abstract: This study aims to develop an innovative natural rubber latex foam (NRLF) composite by incorporating coconut shell activated carbon (Ac) and 2% copper-modified Ac (2%Cu/Ac). The NRLF was prepared using the Dunlop process and mixed with Ac and 2%Cu/Ac at concentrations of 0, 5, and 10 phr. The mechanical properties, morphology, crosslink density, and cadmium ion adsorption performance were investigated. SEM analysis revealed that the additives improved the stability of the foam’s open-cell structure. The results demonstrated that copper particles deposited on Ac enhanced the overall properties of the NRLF composite. The mechanical strength at 50% strain increased significantly, from 5.81 mN/m² for neat NRLF to 12.81 mN/m² with the incorporation of 10 phr 2%Cu/Ac. Crosslink density also improved with the addition of Ac and further increased with Cu-modified Ac. In terms of cadmium adsorption, the optimal performance was achieved with 5 phr 2%Cu/Ac, yielding an adsorption capacity of 0.89 mg/g. These findings highlight the potential of 2%Cu/Ac as a superior additive for enhancing the Cadmium adsorption and the performance of NRLF composites.

Abstract: In this study biowaste-derived carbon electrode materials with improved physical properties for supercapacitor application are synthesized. The chosen biomass is Desmostachya bipinnata, which was activated using a chemical method to improve previous results. The morphological and structural study of the synthesized activated carbon material is carried out using a multi-technique experimental approach revealing the presence of a micro-and nanoporosity and their effects on the physico-chemical performance of the electrode. In order to check the applicability of the process of synthesis, the activated carbon has been tested as electrode material working in a supercapacitor device subjected to cyclic voltammetry analysis. The synthesized material is able to deliver maximum specific capacitance of ~ 167.2 Fg-1, quite one order of magnitude higher than the same material characterized without activation. The results show that Desmostachya bipinnata is an important precursor for electrode materials for energy devices and deserves further studies to make possible its possible use in industrial production routes.