Adsorption Of Volatile Organic Compounds Research Articles

Investigation of the competitive adsorption mechanism between typical volatile organic compounds (VOCs) and water vapor in waste gas emissions from the fermentation industry

ABSTRACT The fermentation waste gas, characterized by high humidity and diverse volatile organic compounds (VOCs), poses challenges for adsorption in activated carbon devices. In this study, starch-based activated carbon was used as an adsorbent, targeting typical VOCs from fermentation industries-methyl mercaptan, toluene, and n-hexane. The adsorption behavior of water vapor and VOCs on the carbon interface was analyzed through adsorption experiments, structure characterization, and molecular simulations. Results showed that at 70% RH, the adsorption capacities of toluene and n-hexane experienced a reduction of 42.15% and 59.24% respectively compared to their respective capacities without water vapor at the breakthrough moment, while methyl mercaptan’s capacity increased by 32.29% due to dissolution in condensed water within micropores. Water displaced all three VOCs during multicomponent adsorption. Reducing surface carboxyl groups, pyrrolic-N, and pyridinic-N enhances selective adsorption of VOCs. Among the VOCs, toluene shows the strongest interaction with activated carbon, followed by n-hexane and then methyl mercaptan. However, a water film under high humidity hinders the adsorption of n-hexane and toluene, reducing selectivity. These research findings will contribute to a comprehensive understanding of the mechanisms underlying the absorption of VOCs in high humidity environments by activated carbon.

Mathematical Expression and Prediction of VOCs Adsorption Capacity and Isotherm.

Adsorption capacity prediction, which needs to be based on the precise structure-capacity relationship, is important for better adsorbent design. However, the precise adsorption contribution coefficients of pores of different sizes for volatile organic compound (VOC) adsorption remain unclear. Herein, a control variable method is employed as a generative model to realize the numerization of the precise structure-capacity relationship. For the first time, a concise equation is proposed that can predict the adsorption capacities/isotherms of unknown adsorbents through their pore structure parameters. Interestingly, practical VOC adsorption amounts aligned with predicted values obtained by simultaneously considering pore volume (which undergoes volume-filling adsorption) and surface area (which undergoes surface-covering adsorption) as input variables. Derivation of the equation is based on classical adsorption theories and mathematical expression of the precise structure-capacity relationship obtained from actual experimental results. Each parameter in the equation has a specific physical meaning. This unprecedented VOC adsorption capacity/isotherm prediction method provides in-depth insight for accurate quantification of VOC adsorption, with great potential for gas adsorption prediction and guidance in the development of adsorption materials and technologies.

Specific and high-affinity adsorption of volatile organic compounds on titanium dioxide surface.

The interaction between metal oxides and volatile organic compounds (VOCs) from the ambient atmosphere plays an important role in environmental and catalytic applications. Previous scanning probe microscopy and x-ray spectroscopy studies revealed surprisingly that the TiO2 [rutile (110)] surface selectively adsorbed atmospheric carboxylic acids, which typically exist in only parts-per-billion concentrations. In this work, we used in situ sum-frequency vibrational spectroscopy to study the interaction between rutile (110) and typical VOC molecules, including formic acid, acetic acid, and formaldehyde. Spectra from all three adsorbed molecules on rutile (110) were similar to the rutile surface spectrum in the ambient atmosphere, showing a broad resonance near 2950cm-1 that can be attributed to the bridging bidentate adsorption of corresponding compounds. In contrast, on a fused silica surface, a molecular monodentate adsorption configuration was observed for all the molecules, with aliphatic carbons appearing to be the dominant adventitious species.

Nitrogen regulation in polyester-based carbons and adsorption of gaseous benzene and ethyl acetate.

Nitrogen doping effectively improves the adsorption properties of activated carbons towards volatile organic compounds (VOCs); however, the role of nitrogen elements with various chemical valence states need further evaluation. In this work, waste polyester fabrics were used as a low-cost source to prepare activated carbon, and melamine, pyridine, dimethylamine, and pyrrole were selected as nitrogen sources to compare their nitrogen-doping ability. The adsorption of low-concentration benzene and ethyl acetate on the resultant carbons and the effects of nitrogen, including its valence states and contents, were investigated. Characterizations showed that the nitrogen contents of carbons after doping with melamine (C-M), pyridine (C-P), dimethylamine (C-D), and pyrrole (C-Y) increased, while their corresponding specific surface areas were about 32.6%, 72.2%, 142% and 14.3%, respectively, of the original carbon value of 188.7 cm2 g-1. Dynamic breakthrough experiments verified the increase in adsorbed amounts of both non-polar benzene and polar ethyl acetate molecules, with a more significant enhancing effect on benzene. The specific surface area and pore volume mainly contribute to the adsorbed amounts. Regarding the influence of nitrogen-containing functional groups, pyridinic nitrogen was more conducive to benzene adsorption under dry conditions because of the stronger π-π interaction and N-H hydrogen bond; however, its water resistance was inferior to that of pyrrolic nitrogen. Saturated C-P can be effectively regenerated and the adsorbed capacity of benzene remained about 75% after five adsorption cycles. The increased adsorbed amount and super regeneration property identify pyridine as a nitrogen source with priority consideration in the nitrogen modification of activated carbons for VOC adsorption.

Advancing characterization of VOC diffusion in indoor fabrics: A dual-porosity modeling approach

Volatile organic compounds (VOCs) are major chemical pollutants in indoor air. Indoor fabrics, such as curtains, carpets, sofas, and clothes, strongly adsorb VOCs due to their high loading rates and large specific surface areas. The desorption of VOCs from these fabrics can act as a secondary source, worsening indoor air pollution and prolonging its effects. The diffusion coefficient is a key parameter that determines the source-sink properties of fabrics. In this study, the VOC diffusion characteristics in fabrics were investigated through microstructural examination, mass transfer analysis, and environmental chamber experiments. Yarn and fiber gaps were identified as dual mass transfer channels within the fabrics and were represented using two distinct fractal models. A dual-porosity medium (DPM) model, based on these fractal representations, was developed to predict the VOC diffusion coefficients in indoor fabrics and was validated via experiments under various environmental conditions and fabric-VOC combinations. The results highlight the significant impact of fabric structure and composition on VOC adsorption and emission dynamics. The validated DPM model provides a comprehensive approach to predicting VOC diffusion in fabrics, providing a more accurate method for assessing indoor air quality and fabric-mediated human exposure.

DFT study of the structures and electronic properties of Au cluster– and Pt cluster–functionalized BC3 nanosheets and their effects on sensing and adsorption of volatile organic compounds

DFT study of the structures and electronic properties of Au cluster– and Pt cluster–functionalized BC3 nanosheets and their effects on sensing and adsorption of volatile organic compounds

Enhanced VOCs adsorption with UIO-66–porous carbon nanohybrid from mesquite grain: A combined experimental and computational study

In this study, adsorption of volatile organic compounds (VOCs) (here just gasoline vapor) by activated carbon- modified UIO-66 was investigated. First, activated carbon prepared from mesquite grain (ACPMG) and then UIO/ACPMG nanohybrid was synthesized by the solvothermal method. In following, the effect of main key parameters which effect on the surface and adsorption capacity such as the ratio of ACPMG to UIO-66 was studied. Physiochemical changes of as- synthesized samples were investigated by TGA, HR-TEM, PSD, SEM, EDX/MAP, BET, FT-IR, XRD, and XPS. It was found the UIO/ACPMG20% nanohybrid had the highest adsorption capacity (391.304 mg/g) for VOCs compared with the other samples, while the adsorption capacity of UIO-66, UIO/ACPMG10% nanohybrid, and UIO/ACPMG30% nanohybrid was 298.871, 309.523, and 320 mg/g respectively. UIO/ACPMG20% nanohybrid desorbed 285.71 mg/g of the adsorbed gasoline, which is an excellent result in desorption. So, the sample of UIO/ACPMG20% nanohybrid was selected as the optimum nano-adsorbent. In other hand, all the nano-adsorbent showed a rapid kinetic behavior for gasoline vapor adsorption and the maximum time for reaching a high adsorption capacity approximately was obtained in 20 min. Density functional theory calculations also performed to understand the adsorption characteristics of gasoline vapor on activated carbon-modified UIO-66.

Enhanced VOCs adsorption on Group VIII transition metal-doped MoS2: A DFT study

Volatile organic compounds (VOCs) represent a significant category of toxic and harmful air pollutants. Among the various abatement techniques available for VOCs, adsorption technology is widely recognized as a cost-effective solution. In this study, density functional theory (DFT) was employed to calculate and compare the adsorption capacities of six typical VOCs on pristine MoS2 and MoS2 modified with Group VIII (MVIII) transition metals atoms. It is found that MVIII-MoS2 monolayer demonstratesa significant enhancement in adsorption capabilities for VOCsrelative to pristine MoS2. Among these Group VIII transition metals atoms, Fe, Ru and Os atoms exhibited the most significant VOCs adsorption enhancement, with Fe atoms demonstrating a particularly pronounced effect. This suggests a synergistic interaction between the metal dopants and the substrate. Density of states (DOS) and charge density difference analyses provided further insights into the mechanisms underlying improved adsorption capability. Interestingly, the introduction of MVIII atoms results in the emergence of a novel state density within the surface state of MoS2, thereby facilitating enhanced electron transfer between VOCs and the substrate. Charge density difference calculations further corroborated these findings, with certain configurations exhibiting significant electron cloud overlap. Such modification leads to more active electron transfer, thereby increasing the substrate’s affinity for VOC molecules and consequently improving the adsorption efficiency. The findings not only enhance the comprehension of VOC adsorption mechanisms on MoS2 but also underscore the potential of metal-doped two-dimensional materials for environmental applications.

Construction of hydrophobic HKUST-1 in wood with selective adsorption performance for toluene and moisture blends

The effect of moisture on the volatile organic compound (VOC) adsorption on biomass-derived metal–organic framework composites is significant in practical applications. In this study, wood-based metal organic frameworks (MOF199-W) and hydrophobic MOF199-W (HMOF199-W) were developed using HKUST-1 (MOF199) and long alkyl chains to investigate the adsorption performance of toluene and enhance the selectivity of adsorption under high humidity conditions. The results demonstrated that HKUST-1 could be anchored onto the surface of wood vessels and fibers through coordination with Cu2+, resulting in an improved surface area in comparison to natural wood. The toluene adsorption capacity of MOF199-W with a 20 % loading was comparable to that of an equivalent amount of MOF199, with adsorption capacities of 323.5 mg/g and 369.9 mg/g, respectively. Further, the Yoon-Nelson model was found to adequately describe the dynamic adsorption process. Following the introduction of long alkyl chains, MOF199 and MOF199-W were endowed with strong hydrophobic character (water contact angle of 107.0◦, 104.0◦, and water uptake of 30.5 mL/g, 55.3 mL/g). With the increase in humidity, the adsorption performance of MOF199 and MOF199-W for toluene sharply decreased, but HMOF199 and HMOF199-W still maintained the adsorption capacities at 304.7 mg/g and 226.7 mg/g, even under 80 % RH conditions. Therefore, HMOF199-W has shown great potential in wooden building materials with the ability for toluene capture under humid conditions.

A theoretical insight into the adsorption behavior of organic molecules on MoS2 monolayer

AbstractThe adsorption stage is crucial in sensing performance and photoreaction on material surfaces. This study investigates volatile organic compounds (VOC) adsorption on MoS2 monolayer using first‐principle calculations. The adsorption configurations are stabilized by H···S hydrogen bonds and C/O···S intermolecular interactions. The process of molecules attached to MoS2 is evaluated as weak physical adsorption and decreases in ordering 1‐propanol > isopentane > acetone > propenal ≈ ethylamine. Besides, AIM analysis indicates that the H···S and C/O···S contacts are weak interactions and are non‐covalent in nature. The intermolecular hyper‐conjugation energy values resulting from the NBO approach determine the stronger hydrogen bonds of H···S in comparison to C/O···S interactions. Remarkably, the gas sensing response of the MoS2 monolayer for VOC molecules is observed theoretically. The sensing responses of gas molecules on the MoS2 monolayer are achieved considerably, up to 99.80% for ethylamine, 97.96% for acetone, and 18–32% for the remaining gases. The MoS2 monolayer is expected to be a suitable sensing material for VOC.

Assessing Adsorption and Desorption Performance in the Recovery of Volatile Organic Compounds

In this study, the activated carbon fiber filter design and VOC adsorption and desorption performance were evaluated based on the development of a filter regeneration device to treat VOCs in high efficiency and low cost. Activated carbon fiber (ACF) has the advantage of fast adsorption speed and high adsorption capacity because micropores are formed on the surface and a large specific surface area. However, the specific gravity is about 25 times lower than that of activated carbon (AC), so the amount of adsorbent that can fill the same volume is small. In order to solve this problem, the regeneration device is implemented by repeating adsorption and regeneration for a short time, and a cylindrical adsorption filter made of activated carbon fiber is designed according to the operating conditions of the regeneration device. At this time, the pollutant gas and regenerated air are uniformly distributed over the entire adsorbent, and the flow characteristics according to the supply of the pollutant gas and the regeneration gas are analyzed. When the size of the lower part of the cylindrical adsorption filter is smaller than the size of the upper part under the condition that the pollutant gas flows downward, a uniform distribution of the pollutant gas is possible. In addition, as the space velocity decreases, the adsorption capacity decreases, and the differential pressure increases rapidly. Through the regeneration experiment, it was confirmed that the desorption concentration of MEK was higher and the desorption concentration was higher. In addition, the regenerated air is uniformly dispersed throughout the adsorption filter, toluene, o-xylene, and methyl ethyl ketone, which are representative substances of volatile organic compounds (VOCs), are injected with 400 ppm, and then regenerated air is supplied at 150 °C to analyze adsorption characteristics and regeneration concentrations. As a result of the experiment, the adsorption capacity ratio to 1 g of regeneration air according to the type of VOCs was 0.48, 0.36, and 0.25 g in the order of o-xylene, toluene, and methyl ethyl ketone. In addition, as the space velocity decreases, the adsorption capacity decreases, and the differential pressure increases rapidly. Through the regeneration experiment, it was confirmed that the desorption concentration of MEK was higher and the desorption concentration of o-xylene was discharged at a relatively low concentration. Moreover, even if the adsorption concentration changes, there was no difference in the regeneration concentration change. Therefore, the filter was designed based on the spatial speed of the regeneration device of 51,000 -h or less, and the adsorption capacity ratio to 1 g of the regeneration air amount was 0.1 g, thereby enhancing the filter's recycling performance and VOCs emission effect.

Movable VOC Removal System

In this study, we develop a mobile VOCs gas removal system that can remove volatile organic compound (VOCs) emissions from petrochemical facilities, metal painting factories, and surroundings of life, and can efficiently cope with situations occurring in the field. Regular repairs to petrochemical plants and semiconductor plants are carried out for a month every four to five years, and work such as replacing old pipes and repairing aging facilities, cleaning, removing residual gas, checking pipe connections and valves, and improving processes are carried out while the plant is shut down. During regular maintenance, a large-scale accident occurs in which gas remaining in the facility leaks or explodes due to rising pressure, and even after internal gas discharge and purge work is performed, it is scattered by the characteristics of raw materials remaining inside the pipe and reactor and discharged into the atmosphere. Therefore, there is always a possibility of causing safety accidents, and such accidents have a great socioeconomic impact as they are directly connected to the safety of workers as well as the safety of local residents. This system is designed to be adaptable according to the size of a number of outlets, and it is proposed to minimize the impact of VOCs harmful gases on the surroundings by developing it as a mobile type. The efficiency of collecting scattered VOCs gas is more than 90%, and the integrated operating system is demonstrated for 50 CMM class movable VOCs adsorption device, 5 CMM class treatment gas recirculation type non-flame waste heat recovery adsorbent regeneration treatment device, and two or more business sites.

Introduction of mesopores effectively enhances the accessibility of volatile organic compounds within the micropores of covalent triazine frameworks

Porous organic polymers (POPs) with abundant pores have great potential for the treatment of volatile organic compounds (VOCs). However, narrow micropores increase gas diffusion resistance and limit the accessibility of VOCs within the micropores. Here, we have synthesized microporous covalent triazine frameworks (mpCTFs) with abundant mesopores using nano-silica. And the effects of the introduced mesopore structure on the sorption performances of CTF were further investigated by 1,2-dichloroethane adsorption. The results indicate that mpCTF12.5 has the most suitable mesopore volume, and its specific surface area and total pore volume are 2.40 and 2.17 times that of CTF, respectively. Meanwhile, the mpCTF12.5 exhibited excellent adsorption performance for methanol, ethanol, acetone, benzene, ethyl acetate, 1,2-dichloroethane and toluene due to the multiple C-H…O, C-H…Cl, O-H…N and C-H…π interactions between VOCs and mpCTFX framework, demonstrated via DFT calculations. Additionally, the two-component gas-competitive adsorption behavior and the impact of water vapor on the adsorption performance of mpCTFX were investigated, with the adsorption mechanism thoroughly analyzed using the GCMC model. The introduction of abundant mesopores undoubtedly shortened the diffusion paths within the micropores of CTFs, significantly enhancing their accessibility for VOC adsorption. This study presents a viable strategy to improve the performance of porous materials in VOC adsorption applications.

Facile and scalable method to synthesize MOFs/PET composite fibers for indoor VOCs adsorption

Volatile organic compounds (VOCs) that are emitted into indoor environments pose significant risks to human health, necessitating air purification to protect individuals from VOC-induced harm. Metal–organic frameworks (MOFs) are characterized by their extensive porosity and accessible metal sites and have attracted significant interest owing to their efficacy in VOC adsorption. However, the inherent difficulty in collecting powdered MOFs hinders their practical application. Thus, integrating MOFs with textiles presents an innovative solution for overcoming these challenges. In this study, MOFs/PET composite textiles (MOFs@STP-PET) were synthesized via an in-situ growth process on polyethylene terephthalate (PET) fiber substrates using thermal crosslinking coating and pre-soaked seed hot-solvent methodologies. The capacities of the composites to adsorb and mitigate VOCs, including benzene and formaldehyde, were evaluated. The presence of carboxyl groups (–COOH) on the polyacrylic acid coating facilitated the chelation of metal ions via electrostatic interactions, providing a foundation for MOF growth. Moreover, the obtained textiles exhibited good adsorption performance. Notably, the 10 % breakthrough time of ethylbenzene on the U6N@STP-PET textile increased to 267.9 min, resulting in a maximum adsorption capacity of 4.3 mg/g. Uniformly anchored MOFs on the fiber surface ensured a high specific surface area of 292.3 m2/g, further enhancing adsorption capabilities. In addition, the textile exhibited excellent mechanical properties, with a tensile strength of approximately 20 MPa. This straightforward, effective, and scalable approach paves the way for the development of novel VOC adsorption materials and holds promise for improving indoor air quality.

Rapid Detection of Explicit Volatile Organic Compounds for Early Diagnosis of Lung Cancer Using MoSi2N4 Monolayer.

In this study, we investigate the adsorption and sensing capabilities of pristine (MoSi2N4) and nitrogen-vacancy induced (MoSi2N4-VN) monolayers towards five potential lung cancer volatile organic compounds (VOCs), such as 2,3,4-trimethylhexane (C9H20), 4-methyloctane (C9H20), o-toluidine (C7H9N), Aniline (C6H7N), and Ethylbenzene (C8H10). Spin-polarized density functional theory (DFT) calculations reveal that MoSi2N4 weakly adsorb the mentioned VOCs, whereas the introduction of nitrogen vacancies significantly enhances the adsorption energies ( ), both in gas phase and aqueous medium. The MoSi2N4-VN monolayers exhibit a reduced bandgap and facilitate charge transfer upon VOCs adsorption, resulting in enhanced values of -0.83, -0.76, -0.49, -0.61, and -0.50 eV for 2,3,4-trimethylhexane, 4-methyloctane, o-toluidine, Aniline, and Ethylbenzene, respectively. Bader charge analysis and spin-polarized density of states (SPDOS) elucidate the charge redistribution and hybridization between MoSi2N4-VN and the adsorbed VOCs. The work function of MoSi2N4-VN is significantly reduced upon VOCs adsorption due to induced dipole moments, enabling smooth charge transfer and selective VOCs sensing. Notably, MoSi2N4-VN monolayers exhibit sensor responses ranging from 16.2 % to 26.6 % towards the VOCs, with discernible selectivity. Importantly, the recovery times of the VOCs desorption is minimal, reinforcing the suitability of MoSi2N4-VN as a rapid, and reusable biosensor platform for efficient detection of lung cancer biomarkers. Thermodynamic analysis based on Langmuir adsorption model shows improved adsorption and detection capabilities MoSi2N4-VN under diverse operating conditions of temperatures and pressures.

Molecular simulation on competitive adsorption of ethanol, acetaldehyde and acetic acid on zeolites in humid conditions

Adsorption is a key technique for purifying volatile organic compounds (VOCs) from indoor air. Due to the complexity of multi-component VOCs and humid environment, the competitive adsorption among VOCs under the influence of water vapor remains unclear, which limits adsorbent selection and performance prediction. In this work, adsorption characteristics of typical indoor VOCs (ethanol, acetaldehyde, and acetic acid) on commercial zeolites (BETA-25 and ZSM5-300) under varying humidity were studied through molecular simulation. The simulation based on charge-corrected molecular structures and force field was validated by experiments. The unary, binary and ternary adsorption isotherms of three VOCs were obtained. At both dry and wet conditions, the VOCs with higher polarity shows greater adsorption capacity: acetic acid > ethanol > acetaldehyde. BETA-25 exhibits stronger adsorption on all three gases under dry conditions, while under wet conditions ZSM5-300 shows greater adsorption capacity of ethanol and acetaldehyde with lower polarity as compared to BETA-25. Simulation of adsorption energy and adsorbate density distribution in ternary equilibrium demonstrates the presence of water vapor alters the sorbate-sorbent interaction, particularly for ethanol and acetaldehyde showing stronger adsorption on BETA-25 than on ZSM5-300 at dry conditions but reversely at wet conditions. The lower-silica zeolite favors the adsorption of highly-polar VOC regardless of water, and the higher-silica counterpart with greater hydrophobicity facilitates adsorption of less-polar compounds in competing with water. The findings in this work can provide methodological reference for adsorbent screening and data basis for real VOCs purification applications.

Synthesis and VOCs adsorption properties of Diatomite/FAU-type zeolite composites

Adsorption technology utilizing zeolites as adsorbents is a highly efficient and cost-effective method for controlling the emission of volatile organic compounds (VOCs). Herein, two hierarchical diatomite/FAU-type zeolite composites were synthesized by a seeding-assisted secondary hydrothermal growth method and high-temperature hydrothermal dealumination, respectively. The adsorption properties of the composites for VOCs, such as toluene, ethyl acetate, n-heptane, methanol and acetone, were systematically evaluated. The pseudo-second-order model provided a perfect fit to adsorption kinetics, while the Langmuir model agreed the best with the adsorption isotherms. Furthermore, Dt/USY has remarkable recycling stability even after five regeneration cycles, resulting in outstanding VOCs adsorption efficacy.

Adsorption of Typical VOCs Onto Ti2CO2 MXene with Implications in Early‐Stage Lung Cancer Diagnosis: A DFT Study

AbstractIn this work, Ti2CO2 MXene is employed as a sensing material to detect volatile organic compounds (VOCs). Using Density Functional Theory (DFT) calculations, the adsorption properties of toluene, isopropanol, formaldehyde, and acetonitrile are calculated and compared. The electronic properties are analyzed to gain insight into the adsorption mechanism. Additionally, the recovery time and sensitivities are studied to evaluate the sensing performance of Ti2CO2 in detecting these VOCs. The results show that the four molecules undergo physisorption. Bader charge analysis shows a small charge transfer from the molecules to the MXene material. The adsorption of these molecules induces changes in the electronic properties of Ti2CO2, particularly in terms of resistance and work function. These changes are used to estimate the sensing response of this material toward these VOCs. Notably, the results highlight that Ti2CO2 exhibits good sensitivity and selectivity, especially in the case of isopropanol. These findings demonstrate the ability of Ti2CO2 as a sensing material for detecting VOCs for the early diagnosis of cancer.

Exploration of the adsorption and desorption performance of volatile organic compounds by activated carbon with different shapes based on fixed-bed experiments

Activated carbon (AC) has been widely used in volatile organic compounds (VOCs) treatment of industrial exhaust gases. Rather than modifying specific pore size distributions and surface properties, altering the shape of AC offers a more feasible approach to enhance its adsorption performance. This study investigates the adsorption-desorption performance of two different shaped ACs with highly similar properties for the removal of VOCs. The clover-shaped AC (CSAC) has a 27.46% lower internal void fraction and a 39.10% higher external void fraction compared to cylindrical AC (CAC), resulting in denser packing and longer contact time with VOCs. Adsorption experiments showed the CSAC has 40% longer adsorption breakthrough (BT) times for ethanol, ethyl acetate, and n-hexane on average, and 20% higher saturation adsorption capacity per unit volume. CSAC also has higher partition coefficients, with the highest values for ethanol, ethyl acetate, and n-hexane being 0.0187, 0.0382, and 0.0527 mol kg−1·Pa−1, respectively. The desorption process for selected VOCs is non-spontaneous and endothermic. Optimal desorption conditions were identified as an inlet space velocity of 3535 h−1, a desorption temperature of 150 °C, and a pulsed inlet method. To investigate the possibility of the application of CSAC in real-world scenarios, xylene was chosen as a representative industrial VOC. Results showed CSAC has 20% higher BT time and saturation adsorption capacity for xylene compared to CAC under different bed heights. The desorption efficiency for xylene on both ACs is below 40%. With increasing xylene inlet concentration, the mass transfer zone (MTZ) height initially increases but stabilizes beyond 1704 mg m−3. At identical bed heights, the MTZ height of CSAC is 29% shorter than CAC, indicating a higher bed utilization efficiency.

3D hydrophobic wood membrane with micro-nano baffle structure for multifunctional air purification filters: “Kill three eagles with one arrow”

Air pollution has presented an imminent threat to the world. Multifunctional filters with high filtration efficiency, low pressure drop, moisture resistance, antibacterial properties, and renewability are urgently needed to be developed. In this study, multifunctional wood filters are innovatively designed with a baffle structure combining macroscopic structural design and microscopic in-situ synthesis of silver nanoparticles (Ag NPs). The filter has excellent particle removal efficiency (PM0.3, 98.5 %), exceptional volatile organic compounds (VOCs) adsorption efficiency (98.4 % for formaldehyde and 91.7 % for xylene), high sterilization efficiency (99.99 %) and excellent regeneration ability (performance recovery to 98 % of the initial). Furthermore, personal protective masks were assembled by the prepared filters, whose process of replacing element is as simple as replacement of electric mosquito incense tablets. This innovative filter holds promise for applications such as daily protection, sudden accidents and prevention and control of respiratory infectious diseases. We envision that the functionally modified Ag NPs wood filters with a multilayer structure offer a comprehensive solution for more effective air purification in polluted environment.