This study aims to prepare bamboo-based activated carbons with surface modifications, focusing on carbon dioxide (CO2) capture in public indoor spaces. The surface of the activated carbon adsorbents was chemically modified through three steps: carbonization, steam activation, and chemical treatment using potassium hydroxide (KOH) and potassium sulfamate (KSO3NH2). The specific surface area and pore volume of the obtained adsorbent (BSAC-KN) were 1,246 m2/g and 0.74 cm3/g, respectively. The surface modification resulted in an adsorption capacity of up to 3.79 mmol-CO2/ g-AC for carbon dioxide. In addition, the expansion of the specific surface area and the enhanced physico-chemical interaction between the weak acidic CO2 molecules and the basic AC surface improved adsorption capacity.
Activated carbon is generally recognized as an applicable material for gas or liquid adsorption and electrochemical devices, such as electric double-layer capacitors (EDLCs). Owing to the continuous increase in its price, research aimed at discovering alternative materials and improving its fabrication yield is important. Herein, organic pigments were ingeniously employed to enhance the fabrication of high-surface-area activated carbon with remarkable efficiency. Moreover, the focus was centered on the assessment of activated carbon derived from 2,9-dimethylquinacridone, also known as CI Pigment Red 122 for its capacity to adsorb tetracycline (TC) and its applicability as an electrode material for EDLCs. Activating these organic pigments with varying potassium hydroxide ratios allowed the fabrication of activated carbon with a higher yield than that for conventional activated carbon. Furthermore, it was confirmed that activated carbon with a very high specific surface area can be efficiently fabricated, demonstrating a remarkable potential in various application fields. Notably, this activated carbon exhibited an impressive maximum specific surface area and a total pore volume of 3,935 m2/ g and 2.324 cm3/ g, respectively, showcasing its substantial surface area and distinctive porous characteristics. Additionally, the Langmuir and Freundlich isotherm models were employed to examine the TC adsorption on the activated carbon, with the Langmuir model demonstrating superior suitability than the Freundlich model. Furthermore, the electrochemical performance of an activated carbon-based electrode for EDLCs was rigorously evaluated through cyclic voltammetry. The specific capacitance exhibited a considerable increase in proportion to the expanding specific surface area of the activated carbon.
Despite the widespread use of polyaniline as a pseudocapacitor material, the cycling stability and rate capability of polyaniline- based electrodes are of concern because of the structural instability caused by repeated volumetric swelling and shrinking during the charge/discharge process. Herein, nanofiber-structured polyaniline was synthesized onto activated carbon textiles to ensure the long-term stability and high-rate capability of pseudocapacitors. The nanoporous structures of polyaniline nanofibers and activated textile substrate enhanced the ion and electron transfer during charge/discharge cycles. The resulting pseudocapacitor electrodes showed high gravimetric, areal, and volumetric capacitance of 769 F g− 1, 2638 mF cm− 2, and 845.9 F cm− 3, respectively; fast charge/discharge capability of 92.6% capacitance retention at 55 mA cm− 2; and good longterm stability of 97.6% capacitance retention over 2000 cycles. Moreover, a symmetric supercapacitor based on polyaniline nanofibers exhibited a high energy of 21.45 Wh cm− 3 at a power density of 341.2 mW cm− 3 in an aqueous electrolyte.
Super P (SP) is a conductive carbon black that significantly enhances the electrical conductivity of various types of electrodes, making it a widely preferred conductive agent in lithium-ion batteries. By contrast, activated carbon (AC), originally used in capacitors due to its porous structure, is expected to contribute to electrochemical performance through its enhanced interaction with lithium ions. First, the physical properties of both materials were analyzed through various characterization techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM) to confirm the increase in electrochemical properties through the combination of SP and AC. Furthermore, the microstructure and electrical properties of the LiFePO4 (LFP) electrode were analyzed, to determine the impact on battery performance. With a 1.15 M LiPF6 in an ethylene carbonate/diethyl carbonate (EC/DEC) electrolyte, the results indicated that SP-only electrodes exhibited the highest conductivity and lowest surface resistance, making them the most effective at maintaining stable electrochemical performance. In contrast, electrodes with only AC showed higher resistance, demonstrating that SP remains superior in improving LFP electrode conductivity, ultimately optimizing lithium-ion battery performance.
The study investigated a method of synthesizing a pitch suitable for making activated carbon using fluid catalytic crackingdecant oil (FCC-DO), a high-purity carbon precursor from oil refining. We kept the reaction time and catalyst amount constant while varying the temperature to investigate its impact on pitch synthesis and the resulting physical and activation properties. Previous research established that materials added during pitch synthesis can affect the properties of both the pitch and resulting activated carbon. This study examined the addition of polyethylene terephthalate (PET) to FCC-DO-based pitch. The results indicated significant changes in properties with PET addition and temperature variation that ensured stable activated carbon quality. At temperatures of 390 °C or higher, the specific surface area of the activated carbon stabilized between 2680 and 2740 m2/ g. Waste PET, a recyclable plastic, was chosen due to its compatibility and thermodynamic suitability for pitch synthesis. Importantly, adding PET didn't generate additional waste or degrade the physical properties of the activated carbon.
Activated carbon has broad application prospects for treating pollutants due to its easy availability, low cost and good adsorption. In our work, nano-activated carbons (NAC) with abundant functional groups are obtained by the oxidation modification of HNO3, ( NH4)2S2O8, and KMnO4, which are used to construct the particle electrodes to degrade NDEA in a continuous flow electrochemical reactor, and the influence of relevant factors on the performance of NDEA removal is discussed. The experimental data show that the optimal degradation efficiency is 42.55% at the conditions of 3 mL/min influent water flow, 0.21 M electrolyte concentration, 10 mA/cm2 current density, and 10 μg/mL initial NDEA concentration. The degradation of NDEA conforms to a quasi second order kinetic equation. The electrocatalytic mechanism of NAC electrodes for removing NDEA is firstly discussed. The effects of different free radicals on the degradation of NDEA are also demonstrated through free radical quenching experiments, indicating that the degradation of NDEA is dominated by ⋅OH. The degradation pathway of NDEA and final products are obtained using GC–MS. NAC particle electrodes as the cheap and efficient electrocatalyst in continuous flow electrochemical reactor system provide a greener solution for the removal of disinfection by-products from drinking water.
In this paper, the adsorption removal characteristic for 10 species of perfluoroalkyl and polyfluoroalkyl substances (PFAS) was investigated using GAC and modified GAC (GAC-Cu). After modification with Cu(II), the amount of copper was to 1.93 and 4.73 mg/g for GAC and GAC-Cu, respectively. The total amount of 10 species of PFAS per specific area was obtained to 0.548 and 0.612 ng/m2 for GAC and GAC-Cu, respectively. A series of batch test confirmed lower efficiency was observed with a smaller number of carbon chain length and the removal efficiency of PFCA (perfluoroalkyl carboxylic acids) was lower than that of PFSA (perfluoroalkyl sulfonic acids) with the same carbon chain length. Regarding the pH effect, the adsorption capacity was decreased with increase of pH due to the increase of electrostatic repulsion. According to pseudo first and second order (PFO and PSO) kinetic models, while the values of equilibrium uptake and time did not show significant difference, a difference in uptake was observed between 24-48h. Furthermore, based on correlation analysis, Log Kow and uptake have a high correlation with molecular weight (M.W.) and initial concentration, respectively. These results show that long-chain PFAS have higher removal efficiency due to their increased hydrophobicity.
This study pioneers a transformative approach of discarded orange peels (Citrus sinensis) into highly porous carbon, demonstrating its potential application in energy storage devices. The porous carbon structure offers a substantial surface area, making it conducive for effective ion adsorption and storage, thereby enhancing capacitance. The comprehensive characterization, including X-ray diffraction, Fourier transform infrared, Raman spectroscopy, field emission scanning electron microscopy, and XPS verifies the material’s suitability for energy storage applications by confirming its nature, functional groups, graphitic structure, porous morphology and surface elemental compositions. Moreover, the introduced plasma treatment not only improves the material’s intensity, bending vibrations, and morphology but also increases capacitance, as evidenced by galvanostatic charge–discharge tests. The air plasma-treated carbon exhibits a noteworthy capacitance of 1916F/g at 0.05A/g in 2 M KOH electrolyte. long term cyclic stability has been conducted up to 10,000 cycles, the calculated capacitance retention and columbic efficiency is 92.7% and 97.6%. These advancements underscore the potential of utilizing activated carbon from agricultural waste in capacitors and supercapatteries, offering a sustainable solution for energy storage with enhanced performance characteristics.
Moso bamboo, as a kind of renewable functional material, exhibits outstanding development potential. It is promising to prepare activated carbon with good mechanical strength and high specific surface area using moso bamboo as raw material. In this work, we employed a hydraulic extruder to extrude the bamboo charcoal and the adhesive to obtain the moso bamboo activated carbon, and improved the specific surface area of the columnar activated carbon through high-temperature water vapor activation. Through the catalytic role of the water vapor activation process, the formation and expansion of the pores were promoted and the internal pores were greatly increased. The obtained columnar activated carbon shows excellent mechanical strength (93%) and high specific surface area (791.54 m2/ g). Polyacrylamide@asphalt is one of the most effective adhesives in the high-temperature water vapor activation. The average pore size (22.99 nm) and pore volume (0.36 cm3/ g) of the prepared columnar activated carbon showed a high mesoporous ratio (83%). Based on the excellent pore structure brought by the activation process, the adsorption capacity of iodine (1135.75 mg/g), methylene blue (230 mg/g) and carbon tetrachloride (64.03 mg/g) were greatly improved. The resultant moso bamboo columnar activated carbon with high specific surface area, excellent mechanical properties, and outstanding adsorption capacity possesses a wide range of industrial applications and environmental protection potential.
In this study, polyimide (PI)-based activated carbon fibers (ACFs) were prepared for application as electrode materials in electric double-layer capacitors by varying the steam activation time for the PI fiber prepared under identical cross-linking conditions. The surface morphology and microcrystal structural characteristics of the prepared PI-ACFs were observed by field-emission scanning electron microscopy and X-ray diffractometry, respectively. The textural properties (specific surface area, pore volume, and pore size distribution) of the ACFs were calculated using the Brunauer–Emmett–Teller, Barrett–Joyner–Halenda, and non-local density functional theory equations based on N2/ 77 K adsorption isotherm curve measurements. From the results, the specific surface area and total pore volume of PI-ACFs were determined to be 760–1550 m2/ g and 0.36–1.03 cm3/ g, respectively. It was confirmed that the specific surface area and total pore volume tended to continuously increase with the activation time. As for the electrochemical properties of PI-ACFs, the specific capacitance increased from 9.96 to 78.64 F/g owing to the developed specific surface area as the activation time increased.
Evaporative emissions, a major cause of air pollution, are primarily produced by automobiles and can be recovered using adsorbents. This study investigated the effect of the textural properties of polyimide (PI)-based activated carbon fibers (PIACFs) on the adsorption and desorption performance of n-butane, which are a type of evaporative emissions. PI-ACFs were prepared by varying the activation time while maintaining the identical crosslinking and carbonization conditions. The surface morphology and microstructural properties of the ACFs were examined using a field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD), respectively. The textural properties of ACF (specific surface area, pore volume, and pore size distribution) were analyzed using N2/ 77 K adsorption and desorption isotherm curves. The n-butane adsorption and desorption performance were evaluated according to modified ASTM D5228. From the results, the specific surface area and total pore volume of ACFs were determined to be 680–1480 m2/ g and 0.28–1.37 cm3/ g, respectively. Butane activity (BA) of the ACFs increased from 14.1% to 37.1% as the activation time increased, and especially it was found to have highly correlated with pore volume in the 1.5–4.0 nm range.
Accurate and rapid detection of antibiotics is critical for protecting human health and the environment. To this end, we report a novel electrochemical sensor for the simultaneous detection of Levofloxacin (LFX) and Tryptophan (TRP) in dairy samples. Outstanding electrocatalytic activity for the oxidation of LFX and TRP is exhibited by the Activated Nanodiamond (AND) and Ti3AlC2 max phase ( Ti3AlC2max) nanocomposite-modified glassy carbon electrode ( Ti3AlC2max AND/GCE) featured in our sensor. High selectivity and sensitivity are achieved by the sensor, with limits of detection (LOD) of 20.47 nM and 0.309 μM for LFX and TRP, respectively. Moreover, strong anti-parasite capacity is demonstrated by the developed sensor, making it an excellent candidate for the establishment of a reliable sensing platform for antibiotic detection. Findings suggest that this novel sensor could serve as a valuable tool for monitoring the content of LFX and TRP in dairy samples and enhancing the safety of these products.
Activated carbon (AC) is a versatile and extensively employed adsorbent in environmental remediation. It possesses distinct properties that can be enhanced to selectively target specific pollutants through modifications, including chemical impregnation or incorporation into composite materials. In this study, porous calcium alginate beads (PCAB) were synthesized by incorporating AC and natural alginate through ion gelation in a Ca(II) ion-containing solution, with the addition of sodium lauryl sulfate as a surfactant. The prepared PCAB was tested for Cu(II) removal. PCAB exhibited a spherical shape with higher porosity and surface area (160.19 m2. g−1) compared to calcium alginate beads (CAB) (0.04 m2. g−1). The adsorption kinetics followed the pseudo-first-order model for PCAB and the pseudo-second-order model for CAB. The Langmuir isotherm model provided the best fit for adsorption on PCAB, while the Freundlich model was suitable for CAB. Notably, PCAB demonstrated a maximum adsorption capacity of 75.54 mg.g−1, significantly higher than CAB's capacity of 9.16 mg. g−1. Desorption studies demonstrated that 0.1 M CaCl2 exhibited the highest efficiency (90%) in desorbing Cu(II) ions from PCAB, followed by 0.1 M HCl and 0.1 M NaCl. PCAB showed efficient reusability for up to four consecutive adsorption– desorption cycles. The fixed-bed column experiment confirmed the match with the Thomas model to the breakthrough curves with qTH of 120.12 mg.g−1 and 68.03 mg.g−1 at a flow rate of 1 mL.min−1 and 2 mL.min−1, respectively. This study indicated that PCAB could be an effective adsorbent for Cu(II) removal, offering insights for further application and design considerations.
In this study, we utilized a multi-step stabilization method, incorporating dry-oxidation, to produce high-density polyethylene (HDPE)-based activated carbon fibers. This stabilization was achieved through electron-beam irradiation, sulfonation, and dry oxidation. The stabilized fibers were carbonized and activated at 900 ℃. The crystallite characteristics of the activated carbon fibers were observed using X-ray diffraction, and their surface morphologies were analyzed through scanning electron microscopy. The textural properties were analyzed using N2/ 77 K adsorption–desorption isothermal curves. And leveraging the microdomain model, we explored the influence of these stabilization methods on the HDPE-based activated carbon fibers texture properties. The results show that HDPE fibers treated with sulfonation only at 100 ℃ for 60 min were not sufficiently cross-linked and were completely decomposed during the carbonization stage. However, the sulfonated fibers treated with the new dry-oxidation process maintained their shapes and were successfully activated. The specific surface area of the resulting activated carbon fibers was as much as 2000 m2/ g.
In this study, Pitch-derived activated carbon (PAC) pellets were by steam activation for automotive carbon canisters. The crystal structure of PAC was analyzed using X-ray diffraction. The textural properties of PAC were studied by Brunauer– Emmett–Teller (BET), Horvath-Kawazoe (HK), and Non-Localized Density Functional Theory (NLDFT) equations with N2/ 77 K isotherm adsorption/ desorption curves. The butane adsorption capacity of the PAC pellets was analyzed according to the ASTM D5228 standard. With increasing steam activation time, the specific surface area and total pore volume of the PAC increased 650–1950 m2/ g and 0.27–1.02 cm3/ g, respectively. The mesopore ratio of PAC increased with increasing activation time and was observed up to 28.4% at 190 min. The butane adsorption capacity of the PAC increased and was observed to range from 10.86 to 51.55%. A close relationship between butane adsorption capacity and pore size (1.47–2.39 nm) was found. Finally, the butane activity of PAC was found to be 51.55% for the steam activated at 950 ℃ for 190 min; this butane activity is 24% better than that of the coconut-derived activated carbon (41.43%) with a similar specific surface area, indicating that pitch is a suitable material for the activated carbon of automotive carbon canisters.
This research investigated the preparation of activated carbon derived from Krabok (Irvingia malayana) seed shells to improve the quality of crude glycerol obtained during biodiesel production. The activated carbon was prepared using a dry chemical activation method with NaOH, utilizing an innovative biomass incinerator. The results revealed that the resulting KC/AC-two-step exhibited favorable physicochemical adsorption properties, with a high surface area of 758.72 m2/g and an iodine number of 611.10 mg/g. These values meet the criteria of the industrial product standard for activated carbon No. TIS 900-2004, as specified by the Ministry of Industry in Thailand. Additionally, the adsorption efficiency for methylene blue reached an impressive 99.35 %. This developed activated carbon was then used to improve the quality of crude glycerol obtained from biodiesel production. The experimental results showed that the KC/AC-two-step increased the purity of crude glycerol to 73.61 %. In comparison, commercially available activated carbon (C/AC) resulted in a higher crude glycerol purity of 81.19 %, as analyzed by the GC technique. Additionally, the metal content (Zn, Cu, Fe, Pb, Cd, and Na) in purified glycerol using KC/AC-two-step was below the standards for heavy metals permitted in food and cosmeceuticals by the Food and Drug Administration of Thailand and the European Committee for Food Contact Materials and Articles. As a result, it can be inferred that Krabok seed shells have favorable properties for producing activated carbon suitable as an adsorbent to enhance crude glycerol purity. Furthermore, the improved crude glycerol from this research has potential for various industrial applications.
In this work, the trend in the performance of carbon fiber (CF) and its composite during self-polymerization of polydopamine (PDA) at carbon fiber surface was investigated by varying the self-polymerization time of dopamine in an aqueous solution. Research has shown that the PDA coating elevated the surface roughness and polarity of the inert fiber. The tensile strength of single carbon fiber was significantly improved, especially after 9 h of polydopamine self-polymerization, increasing by 18.64% compared with that of desized carbon fiber. Moreover, the interlaminar shear strength (ILSS) of CF-PDA9-based composites was 35.06% higher than that of desized CF-based composites. This research will provide a deep insight into the thickness and activated ingredients of dopamine oxidation and self-polymerization on interfacial compatibility of carbon fiber/epoxy resin composites.