Pore Structure Of Activated Carbon Research Articles

The Role of Lignin Molecular Weight on Activated Carbon Pore Structure.

Over the past decade, the production of biofuels from lignocellulosic biomass has steadily increased to offset the use of fuels from petroleum. To make biofuels cost-competitive, however, it is necessary to add value to the "ligno-" components (up to 30% by mass) of the biomass. The properties of lignin, in terms of molecular weight (MW), chemical functionality, and mineral impurities often vary from biomass source and biorefinery process, resulting in a challenging precursor for product development. Activated carbon (AC) is a feasible target for the lignin-rich byproduct streams because it can be made from nearly any biomass, and it has a market capacity large enough to use much of the lignin generated from the biorefineries. However, it is not known how the variability in the lignin affects the key properties of AC, because, until now, they could not be well controlled. In this work, various fractions of ultraclean (<0.6% ash) lignin are created with refined MW distributions using Aqueous Lignin Purification using Hot Agents (ALPHA) and used as precursors for AC. AC is synthesized via zinc chloride activation and characterized for pore structure and adsorption capacity. We show that AC surface area and the adsorption capacity increase when using lignin with increasing MW, and, furthermore, that reducing the mineral content of lignin can significantly enhance the AC properties. The surface area of the AC from the highest MW lignin can reach ~1830 m2/g (absorption capacity). Furthermore, single step activation carbonization using zinc chloride allows for minimal carbon burn off (<30%), capturing most of the lignin carbon compared to traditional burn off methods in biorefineries for heat generation.

Highly efficient regeneration of VOCs-saturated activated carbon by vacuum-thermal treatment

The substantial energy consumption and carbon loss associated with conventional thermal regeneration of activated carbon (AC) pose significant constraints on the advancement of deactivated AC recycling. Here, a vacuum-thermal process was applied to regenerate AC saturated with VOCs. Results showed that desorption efficiency under vacuum conditions (99 % at 200 °C) was significantly higher than that in air and nitrogen (85.2 % and 86.4 %, respectively). The adsorption capacities of different AC samples were maintained at 74.2 %, 97.8 %, 90.9 %, and 96.4 % after seven regeneration cycles, respectively. Pore structure analysis showed that vacuum-thermal regeneration caused less damage to the AC pore structure compared to the air and nitrogen. In addition, micropores were shown to be most conducive to the adsorption of VOCs, while mesopores larger than 4 nm are conducive to desorption. The larger the saturated vapor pressure of the VOCs, the larger the driving force it is subjected to, and the easier it is to desorption. Density field theory (DFT) calculations showed that the higher the binding energy between VOCs and AC surface, the more stable the adsorption system, making it more difficult to regenerate the adsorbent. This work provides insight into the development of an economical and environmentally friendly regeneration route for AC adsorption.

Activated Carbons for Removing Ammonia from Piggery Vent Air: A Promising Tool for Mitigating the Environmental Impact of Large-Scale Pig Breeding

Unsustainable pig breeding is a great threat to the environment. Ammonia is one of the main pollutants emitted in piggery vent air. This work is a comparative survey that presents the findings on the effectiveness of ammonia adsorption from air using various activated carbons (ACs). Detailed consideration is given to the effects of (i) type of raw material (wood char, wood pellet, and commercial lignite-based char), (ii) preparation method (CO2, steam, and KOH activation), and (iii) activation conditions (temperature and KOH/char ratio), on the porous structure of ACs and their ammonia sorption capacity and reversibility. Response surface methodology and genetic algorithm were used to find optimum KOH activation conditions. Economic analyses of AC production were performed using process modeling in Aspen software. It was found that ACs obtained from wood char in KOH activation show a maximum ammonia capacity of 397 g/kg, which is at least 2.5-fold higher than that reached on ACs from physical activation. A lower activation temperature (&lt;750 °C) and a higher KOH/char ratio (&gt;3) were preferred for effective adsorption, regardless of the type of feedstock. High sorption reversibility was achieved (87–96%). This makes the obtained sorbents promising sorbents for ammonia removal from piggery vent air with potential subsequent application as nitrogen-enriched biochar for crop fertilization. Thus, it facilitates sustainable pig breeding.

Activation of poplar and spirulina with H3PO4: Marked influence of biological structures of the biomasses on evolution structure of activated carbon

Terrestrial and aquatic biomasses can theoretically be used as feedstocks for producing activated carbon (AC). However, their differences in composition and biological structure would affect pore characteristics of resulting AC. In this work, activation of poplar and spirulina with H3PO4 at medium to high temperatures (400, 550 and 700 °C) was conducted, which was followed by detailed characterization of the produced AC. The results showed that the presence or absence of sugary structures in poplar and spirulina made marked difference in evolution of pore structures of AC. The oligomers derived from cellulose/hemicellulose in poplar crosslinked with phosphates via esterification/polycondensation and further aromatized with temperature. This turned H3PO4-derivatives into skeleton of the poplar-derived AC, which served as the base for creating the AC obtained at 400 °C with highest specific surface area (1380.9 m2g−1) and capability for adsorption of tetracycline (68.8 mg/g). In comparison, low content of carbohydrate together with thermal melting and agglomeration of proteins/lipids in spirulina produced the AC with sponge-like morphology and maximum specific surface area of only 157.1 m2g−1. H3PO4 efficiently catalyzed conversion of -OH and CO in sugary structures of poplar, forming stable CO bonds, which, however, did not work in activation of spirulina.

Activation of pine needles with zinc chloride: Evolution of functionalities and structures of activated carbon versus increasing temperature

Functionalities of activated carbon (AC) is one of the essential factors determining its performance for adsorption. In this study, the evolution of functionalities and structure of AC from activation of pine needles with ZnCl2 versus temperature was explored. The results indicated that the ZnCl2 activator could remarkably increase yields of solid product (AC) via catalyzing dehydration, condensation and aromatization of sugary structures, minimizing the formation of aliphatic and phenolic organics in bio-oil. The pore structures of AC generated by this process also exhibited high sensitivity to temperature. The specific surface area of resulting AC could increase from 699.2 m2g−1 at 400 °C to 2030.2 m2g−1 at 500 °C, which could also decrease to 907.9 m2g−1 at 700 °C. Migration and aggregation of ZnO at 700 °C resulted in the loss of capability for supporting carbon structures, leading to shrinkage or collapse of the pore structures. The characterization with in-situ IR technique showed that ZnCl2 catalyzed dehydration of hydroxyl group and conversion of carbonyls in aldehydes/ketones into larger π-conjugated structures but not worked on the C-O-C bonds for bridging benzene rings. However, the transformation of ZnCl2 to ZnO above 500 °C lost the catalytic activity, inducing little change of elemental composition but re-structuring of AC through merge of pores.

Activation of mixed sawdust and spirulina with or without a pre‑carbonization step: Probing roles of volatile-char interaction on evolution of pyrolytic products

Volatile-char interaction has been well documented in co-pyrolysis of varied feedstocks, which might also exist in activation process and impact pore evolution of activated carbon (AC). This was investigated herein in activation of mixed sawdust and spirulina with K2C2O4 at 800 °C in two scenarios: one-step direct activation or two-step activation with an intermediate pre‑carbonization. The results showed that volatile-char interaction via cross-polymerisation of the volatiles was more significant in the pre‑carbonization step, forming more biochar/bio-oil while less gases. However, volatile-char interaction was not that important in impacting product yields and evolution of pore structures of AC in activation. This was due to the dominance of gasification/cracking with presence of K2C2O4, minimizing the chances for volatile-char interaction. The in-situ DRIFTS characterization of the activation process showed that removal of oxygen-containing species like CO with K2C2O4 was important for generating pore structures. Comparing with two-step activation, one-step activation of sawdust, spirulina and their mixture without pre‑carbonization all generated the ACs of more developed pore structures and showed higher environmental impact. The pre‑carbonization removed a significant portion of thermally unstable aliphatic structures, enhancing aromatic degree and creating difficulty for generating pores via gasification/cracking in subsequent activation.

The significance of granular activated carbon pore structure in modeling dissolved organic carbon removal in fixed-bed filters

A reliable model that describes DOC removal during biological-active granular activated carbon filtration for advanced wastewater treatment has to cover several aspects that influence biological and adsorptive removal processes. For this purpose, this work introduces a two-domain internal diffusion approach to a multicomponent adsorption model, which is combined with a traditional biofilm model for the first time. DOC was divided into fictive components according to biodegradability and adsorbability to calculate multicomponent adsorption equilibrium based on the ideal adsorbed solution theory. Adsorption kinetics included external mass transfer (diffusion through a boundary layer and a biofilm) and internal mass transfer (fast pore diffusion in the larger pores and slow surface diffusion in the micropores). Mass transfer in the micropore domain was implemented by adjusting the adsorptive driving force depending on the available internal surface area for DOC adsorption based on an empirical surface diffusion model. Simulated DOC breakthrough curves were sensitive to model parameters related to the pore structure of the granular activated carbon (GAC). The model was validated with two GAC types and empty bed contact times ranging between 6 and 33 min. The model results showed a good agreement with measured DOC breakthrough curves over the entire operation time, demonstrating the applicability and transferability of the model. In particular, the initial DOC breakthrough was well represented. However, some systematic deviations between measured and simulated DOC breakthrough curves were observed, which are probably due to the level of detail of the implemented biofilm model.

Quaternary ammonium salts targeted regulate the surface charge distribution of activated carbon: A study of their binding modes and modification effects

Activated carbon (AC) is negatively charged in aqueous solution, which seriously restricts its application range. Quaternary ammonium salt as a common cationic surfactant was utilized to modify the surface charge distribution of materials. The evolution of the surface charge distribution of AC modified by benzalkonium chloride (BAC), diallyl dimethyl ammonium chloride (DDA) and 3-chloro-2-hydroxypropyl tri-methyl ammonium chloride (CTA) was investigated. Results showed that the surface charge of AC modified by CTA does not change significantly. BAC has a high molecular weight, low surface electrostatic potential and large steric hindrance due to its hydrophobic long-chain alkyl. The diffusion of BAC molecules from solution to AC changed its charge distribution. But these molecules were difficult to combine with AC surface, and most of them were adsorbed into the pores of AC to form aggregates, resulting in a significant reduction in the surface area. BAC modified AC could enhance the adsorption capacity of F− in aqueous solution through electrostatic attraction, but the improvement effect was limited due to the reduction of surface area, and the maximum adsorption capacity was only increased from 1.18 to 3.31 mg/g. DDA has a small molecular weight and high surface electrostatic potential and easily binds to the surface of AC. Some CC bonds in DDA combined with the ionized hydrogen ions derived from phenolic hydroxyl groups in AC to form carbonium-ions. Then, they could react with AC to form ether bonds, causing DDA to be closely bonded with the surface of AC. DDA realizes the targeted regulation of the surface charge distribution of AC, it has little effect on the porous structure of AC. The modified AC still maintained strong adsorption capacity, and the maximum adsorption capacity for F− was 54.98 mg/g. Meanwhile, a large number of zeolites were loaded on the modified AC and formed coating structures.

Adsorptive separation of carbon dioxide at ambient temperatures in activated carbon

Gas adsorption by activated carbon (AC) is one of the common approaches applied in industries for separation and purification purposes, e.g., air purification, hydrocarbon processing, and carbon capture and storage. Understanding the preferential adsorption of the adsorbates in the gas mixture is crucial for improving separation technologies. With the develop ment of computational technology, molecular simulation is recognized as a useful tool that can be important compensation for experimental study. A uniform slit pore is commonly used for representing the AC. However, the pore structure of AC is rather complex and is composed of randomly stacked crystallites. Moreover, the confined spaces between the carbon stacks tend to be irregular-shaped. The wedge pore model was used to represent the non-uniformity of AC as its size continuously changes in the axial direction. In this regard, a systematic Monte Carlo simulation was conducted to study the adsorption of bi nary mixtures containing carbon dioxide with methane or nitrogen at the ambient temperatures (i.e., 273–298 K) in slit and wedge-shaped pores with graphitic surfaces. The results were also compared with experimental data and predicted values using Ideal Adsorbed Solution Theory (IAST). The results of the single wedge pore model agreed at low pressure for single and multicomponent adsorption of experimental data and IAST predictions, while the results of the combination of slit pore with various pore widths were also well fitted or were close to the experimental data and compared to IAST predictions. It is evident from the results that the wedge pore can be the alternative pore model for the AC to reveal some important characteristics and mechanisms for pure and mixture adsorption.

Modification, Production, and Methods of KOH‐Activated Carbon

AbstractThis review covers research on the use of potassium hydroxide (KOH) to produce and modify activated carbon. The methods employed for activation by considering the activation process, carbonization, temperature, activation time, and KOH ratio to material are described and how the surface area, surface morphology, and functional groups are affected by the KOH ratio. Characterization techniques and preparation conditions are summarized. The activated carbon pore structure mainly depends on the burn‐off size and the time for activation is linked to the overall activation reaction rate. The increase in surface area and pore size depends on the ratio of KOH, showing that KOH affects the surface chemistry of the activated carbon. The sorbent‐sorbate interactions are strongly influenced by different parameters, which were also calculated in this review and used to evaluate such interactions.

Effect of activated carbon’s pore size distribution on oxygen induced heel build-up

Thermal desorption of volatile organic compounds (VOCs) from activated carbon (AC) is negatively impacted by oxygen. Oxygen reacts with the adsorbed VOCs, resulting in heel buildup in the porous structure of AC and reducing its adsorption capacity. This study investigated the contribution of physical properties of AC (specific surface area, micropore volume, and total pore volume) to this type of heel. Three different ACs with different micro/mesopore structures were tested through cyclic adsorption/desorption of 1,2,4-trimethylbenzene (TMB) using ultra-pure nitrogen (≤5 ppmv O2) as the purge gas during thermal desorption. Each set of experiments was repeated with dry air (21% O2) to evaluate the effect of O2 on heel build-up. Pore size distribution (PSD) analysis on the adsorbents cycled in dry air suggested a correlation between the amount of heel and the microporosity of adsorbents. Differential thermogravimetric (DTG) analysis was used to distinguish between the physically adsorbed and chemically formed heel. X-ray photoelectron spectroscopy (XPS) analysis showed a noticeable increase in surface oxygen content of the ACs desorbed in air. Finally, Boehm titration confirmed the presence of different surface oxygen functional groups on these adsorbents, suggesting oxidation reactions as the main mechanism of heel build-up.

A systematic preparation mechanism for directional regulation of pore structure in activated carbon including specific surface area and pore hierarchy

Currently, the simultaneous and directional regulation of specific surface area (SBET) and pore hierarchy (the percentage of mesoporous and macroporous volume to total pore volume, Vmes+mac/Vt) of activated carbon (AC) lacks a systematic preparation mechanism. In this study, AC samples were prepared from coconut husks, and the effect of carbonization methods, activation methods, and process parameters on the development of the pore structure were explored. N2 adsorption–desorption results indicated that AC samples prepared via conventional carbonization were microporous. Hierarchical AC samples were obtained by the combination of hydrothermal carbonization at 240 °C and physical activation. CaCl2 impregnation was found to be beneficial to the preparation of meso-/macroporous AC samples. Based on these results, a series of AC samples with typically varied pore hierarchies (18.05–76.73 %) with similar specific surface areas (∼450.0 m2 g−1) were obtained. AC samples with similar pore hierarchies and different specific surface areas were also prepared, including microporous AC (SBET: 330.5–761.4 m2 g−1; Vmes+mac/Vt: 12.21–14.06 %), hierarchical AC (SBET: 445.9–780.7 m2 g−1; Vmes+mac/Vt: 51.04–54.89 %), and meso-/macroporous AC samples (SBET: 371.1–516.0 m2 g−1; Vmes+mac/Vt: 67.39–75.25 %). A systematic preparation mechanism for the directional regulation of the pore structure of AC is proposed, which is significant for the preparation of high-efficiency AC for different applications.

A study on pore formation of high surface area activated carbon prepared by microwave-induced plasma with KOH (MiWP-KOH) activation: Effect of temperature-elevation rate

The activation using microwave-induced plasma with KOH (MiWP-KOH activation) can realize extremely fast synthesis of activated carbon (AC), which needed only several minutes. The present work focusses the effect of temperature-elevation rate on pore formation. For the discussion, AC was prepared using a conventional heat conduction method with various temperature-elevation programs, and the structural analysis results from these experiments were compared with those observed in AC prepared by the MiWP-KOH activation. As a feature in the pore structure of AC induced by the MiWP-KOH activation, micropore volume highly dominates over mesopore volume with (micropore/mesopore) ratio = 4.3–4.9. This property can be explained by the experiments with the controlled temperature-elevation rate, suggesting that rapid temperature-elevation rate is the key factor for such micropore-dominating structure. Additionally, it was suggested that the temperature of the feed material in the MiWP-KOH activation can become about 800 °C within 75 s. MiWP-KOH activation can generate significantly higher surface area than the conventional heating with the similar temperature changing program, suggesting the effect of microwave irradiation to enhance the pore formation. Based on these investigations, a characteristic pore formation model in the MiWP-KOH activation is considered.

Are activated carbon pore structure parameters linearly positively related to its mass-specific capacitance?

Despite considerable achievements in the use of porous carbon in electrochemical double-layer capacitor or electrode of supercapacitor over the past few years, understanding the relationship between pore structure parameters and electrochemical performance has long been highly desirable. Herein, apricot shell lignin (ASL) was used to prepare activated carbon, after which the galvanostatic charge–discharge (GCD) test was performed. Meanwhile, the pore structure parameters of AAC were determined by the nitrogen adsorption–desorption test. The results confirmed that the AAC pore structure parameters were consistent with the inherent law of activation. Besides, in the low current density ranging from 0.50 A/g to 10.00 A/g, the micropore surface area density of AAC rather than other pore structure parameters (e.g., mesoporosity, micropore specific surface area, mesopore specific surface area) was linearly positively related to its mass-specific capacitance. Additionally, the average of linear fit coefficients between micropore surface area density and mass-specific capacitance was 0.92. Consequently, when using a three-electrode configuration with a 6 M KOH electrolyte, the micropore surface area density of activated carbon can be employed as a universal predictor of mass-specific capacitance in a low current density range 0.50–10.00 A/g.

Synthesis and Characterisation of Pyridinium-Based Ionic Liquid as Activating Agent in Rubber Seed Shell Activated Carbon Production for CO2 Capture

The use of an activating agent in chemical activation of activated carbon (AC) production is very important as it will help to open the pore structure of AC as adsorbents and could enhance its performance for adsorption capacity. In this study, a pyridinium-based ionic liquid (IL), 1-butylpyridinium bis(trifluoromethylsulfonyl) imide, [C4Py][Tf2N] has been synthesized by using anion exchange reaction and was characterized using few analyses such as 1H-NMR, 13C-NMR and FTIR. Low-cost AC was synthesized by chemical activation process in which rubber seed shell (RSS) and ionic liquid [C4Py][Tf2N] were employed as the precursor and activating agent, respectively. AC has been prepared with different IL concentration (1% and 10%) at 500°C and 800°C for 2 hours. Sample AC2 shows the highest SBET and VT which are 392.8927 m2/g and 0.2059 cm3/g respectively. The surface morphology of synthesized AC can be clearly seen through FESEM analysis. A high concentration of IL in sample AC10 contributed to blockage of pores by the IL. On the other hand, the performance of synthesized AC for CO2 adsorption capacity also studied by using static volumetric technique at 1 bar and 25°C. Sample AC2 contributed the highest CO2 uptakes which is 50.783 cm3/g. This current work shows that the use of low concentration IL as an activating agent has the potential to produce porous AC, which offers low-cost, green technology as well as promising application towards CO2 capture.

A cost-effective synthesis of heteroatom-doped porous carbon by sulfur-containing waste liquid treatment: As a promising adsorbent for CO2 capture

Based on efficiency and environmental concerns, the development of porous carbon from waste and biomass materials has attracted extensive attention as a novel approach. In this study, poplar sawdust was an inexpensive carbon precursor, sulfur-containing waste liquid (SCWL) was used as a modifier to turn waste into treasure, and potassium oxalate (K2C2O4) was a mild activator, successfully prepared N, S, O co-doped new porous activated carbon with excellent CO2 capture performance. The heteroatom doping and pore structure can be controlled by using SCWL and K2C2O4, and adjusting the activation temperature. The best sample (PCSK-2-3-800) prepared with SCWL and K2C2O4 showed excellent CO2 adsorption performance, reaching 3.82 and 5.61 mmol/g under normal pressure at 25 and 0 °C, respectively. This is attributed to the synergy of porous structure and surface chemistry. The pore structure parameter results showed that K2C2O4 promotes the development of activated carbon pore structure. The specific surface area, micropore volume and narrow micropore volume of PCSK-2-3-800 are 1418 m2/g, 0.55 cm3/g and 0.43 mL/g, respectively. The characterization results of FTIR and XPS showed that the addition of SCWL can successfully introduce heteroatoms into the carbon skeleton, and form CO2-philic active sites on the surface of the porous carbon. Both aspects promoted the adsorption of CO2. In addition, the PCSK-2-3-800 sample has a moderate adsorption heat of 27.13 kJ/mmol, good adsorption selectivity of CO2 and N2 is 13, and excellent recyclability, which is very promising for CO2 separation or storage. This paper develops a sustainable scheme for the first-time using biomass and SCWL to develop a new solid carbon adsorbent, which provides useful information and inspiration for capturing CO2.

Methylene Blue Dye Photocatalytic Degradation over Synthesised Fe3O4/AC/TiO2 Nano-Catalyst: Degradation and Reusability Studies.

In this study, activated carbon (AC) from coconut shell, as a widely available agricultural waste, was synthesised in a simple one-step procedure and used to produce a magnetic Fe3O4/AC/TiO2 nano-catalyst for the degradation of methylene blue (MB) dye under UV light. Scanning electron microscopy revealed that TiO2 nanoparticles, with an average particle size of 45 to 62 nm, covered the surface of the AC porous structure without a reunion of its structure, which according to the TGA results enhanced the stability of the photocatalyst at high temperatures. The photocatalytic activities of synthesised AC, commercial TiO2, Fe3O4/AC, and Fe3O4/AC/TiO2 were compared, with Fe3O4/AC/TiO2 (1:2) exhibiting the highest catalytic activity (98%). Furthermore, evaluation of the recovery and reusability of the photocatalysts after treatment revealed that seven treatment cycles were possible without a significant reduction in the removal efficiency.

The effect of different binders on the comprehensive performance of solid phase microextraction fiber

Binders are significant components for the preparation of solid-phase microextraction (SPME) fibers. However, little attention has been paid to the effect of different binders. Considering their diverse properties, in this work, we select three kinds of commonly used binders including polydimethylsiloxane (PDMS), polyacrylonitrile (PAN) and Nafion, as well as introduce a new binder of poly (vinylidene fluoride) (PVDF) to synthetically study the influence of binders. By using the commercial active carbons (ACs) with different binders, four SPME fibers with uniform morphologies and comparative thicknesses (i.e., ACs-PDMS-coated, ACs-PAN-coated, ACs-Nafion-coated and ACs-PVDF-coated fibers) have been prepared successfully. The effect of binders on the pore structure of ACs is firstly investigated. It is found that PDMS and PAN would cause pore blocking, and the specific surface area of ACs coatings decreases from 1362 m2 g−1 to 280 and 196 m2 g−1, respectively. While the specific surface area of ACs-PVDF composite remains 940 m2 g−1. Based on SPME, the influences of acid/alkali, high temperature and matrix towards different fibers are further systematically surveyed. Finally, the enrichment performance of prepared fibers towards various organic pollutants is preliminarily discussed. The comparison results show that PVDF demonstrates outstanding stability in all aspects. Therefore, PVDF might be an excellent candidate for the preparation of SPME fiber. Moreover, all obtained results are expected to provide the reference value for the further development of novel SPME fibers.

Activated Carbons and Their Evaluation in Electric Double Layer Capacitors.

This review presents a summary of the manufacturing of activated carbons (ACs) as electrode materials for electric double layer capacitors. Commonly used techniques of open and closed porosity determination (gas adsorption, immersion calorimetry, X-ray and neutrons scattering) were briefly described. AC production methods (laboratory and industrial) were detailed presented with the stress on advantages and drawbacks of each ones in the field of electrode materials of supercapacitor. We discussed all general parameters of the activation process and their influence on the production efficiency and the porous structure of ACs. We showed that porosity development of ACs is not the only factor influencing capacity properties. The role of pore size distribution, raw material origin, final carbon structure ordering, particles morphology and purity must be also taken into account. The impact of surface chemistry of AC was considered not only in the context of pseudocapacity but also other important factors, such as inter-particle conductivity, maximal operating voltage window and long-term stability.

Activated Carbon Modified by Nanosecond Pulsed Discharge for Polycyclic Aromatic Hydrocarbons Detection

In this paper, a nanosecond pulsed discharge was employed to modify activated carbon (AC) adsorbents for the purpose of detecting gas-phase polycyclic aromatic hydrocarbons (PAHs). The raw and modified AC were characterized by helium ion microscopy, N2 adsorption/desorption, and X-ray photoelectron spectroscopy. The treatment time, gas composition, and pulse peak voltage of discharge were optimized to improve the adsorption capacity of AC. And the adsorption kinetics of AC was investigated. It is found that the pore structure of AC is changed and the oxygen-containing groups on AC surface are increased after plasma treatment. As a result, the roles of physisorption and chemisorption are promoted, and the adsorption rate of naphthalene is improved by about 10%. More importantly, modified AC adsorbing PAHs obeys Pseudo-first-order model and Langmuir isotherm model, and the corresponding adsorption coefficients are fitted, which contributes to detecting PAHs more accurately. After modified AC enriching, the gas-phase PAHs can be detected with the limit of detections in the range of 20–120 μg/m3.