Volatile organic compounds (VOC) can have harmful effects on human health. Physisorption using carbon-based materials is one of the most commonly used methods for removing toxic VOC from indoor air. In this study, three carbon-based materials, including hydrophilic granular activated carbons (GAC1 and GAC2) and hydrophobic Carbotrap X (CX), were investigated for toluene adsorption using a novel dynamic set-up. The efficiency of toluene removal can vary depending on several experimental factors. Therefore, adsorption experiments were conducted under stable and precisely controlled conditions of temperature, humidity, flow rate, and pollutant concentration. Our findings show that adsorption temperature, high humidity, and the textural properties of the materials can influence toluene adsorption capacity. Additionally, pollutant concentration plays a role, as demonstrated by adsorption isotherm models such as Langmuir, Freundlich, Temkin, and Redlich-Peterson. The results indicate that GAC1, with its large specific surface area (SSA = 974 m²/g) and high micropore content (>80%), is a promising material for toluene physisorption in indoor air at a medium relative humidity (≤ 50% RH). Its adsorption capacity can reach up to 342 ± 41 mg/g under conditions of 14–20 mg adsorbent mass, 23 °C, 50% relative humidity, and 40–200 mL/min flow rate. Notably, hydrophobic CX shows potential as an effective VOC adsorbent material, particularly in extremely high-humidity environments. • Toluene adsorption on carbon-based materials was studied under strictly controlled conditions. • Temperature, humidity, and material texture, i.e., surface area and micropore structure, govern toluene adsorption efficiency. • High humidity (80% RH) reduced toluene uptake by ~45% on hydrophilic granular activated carbons (GAC). • Adsorption capacity on hydrophobic graphitized carbon black (CX) was constant (~10 mg/g) at 50–80% RH, 23°C and 10 ppm. • Maximum adsorption capacities of 342 mg/g for GAC1 and 15 mg/g for CX were achieved at 23°C and 50% RH.

Recent advances in modified In2O3-based gas sensors for ultra-sensitive formaldehyde detection.

Hierarchical SnO2/NiO microflowers via heterojunction engineering for high-sensitive ppb-level xylene detection.

ABSTRACT In the commercial production of acrylic and vinyl polymers, trace amounts of oxygen can significantly disrupt free‐radical polymerization by generating toxic volatile organic compounds (VOCs), retarding polymerization, and altering polymer properties. To establish a mechanistic understanding of these effects across industrially relevant monomers, this work examines the influence of oxygen on the solution homopolymerizations of butyl acrylate (BA), vinyl acetate (VAc), and methyl methacrylate (MMA). Systematic experiments conducted under nitrogen and air reveal pronounced monomer‐dependent behavior: BA and VAc exhibit severe retardation and form only oligomeric species, while MMA continues to polymerize but shows substantial reductions in molar mass. In all three systems, the presence of oxygen promotes the formation of toxic VOCs, with the extent of oxidation increasing sharply as monomer concentration decreases. To complement the experimental findings, a mechanistic kinetic model is developed for MMA, enabling prediction of monomer conversion, VOC formation, and molecular‐weight evolution under oxygen‐containing conditions. Together, this work provides a unified framework for understanding oxygen‐induced defects in industrial free‐radical polymerization processes involving acrylic and vinyl monomers.

Ethanolamine (EA) is a widely used yet toxic volatile organic compound (VOC). However, existing gas sensors for EA detection face persistent challenges in achieving exceptional sensitivity and low detection limits at room temperature (RT). In this study, a novel and high-performance EA sensor based on the MoO3/BiOI composite was prefabricated using hydrothermal and cyclic impregnation methods. The response value toward 100 ppm EA reached 861.3, which was 3.5-times higher compared to that of pure MoO3. In addition, the MoO3/BiOI composite exhibited a low detection limit (0.13 ppm), excellent selectivity, short response/recovery times, exceptional repeatability and long-term stability. The outstanding gas sensing performance of the MoO3/BiOI is attributed to the formation of a p-n heterojunction, synergistic effects between the two materials, abundant adsorbed oxygen species and superior charge transfer efficiency. The sensor developed in this work effectively addresses the long-standing challenges, demonstrating unprecedented practical application potential for EA gas detection. Simultaneously, this study provides a novel strategy, a new approach and a promising material for the subsequent development of advanced amine sensors.

Deep Eutectic Solvents (DESs) based on abundant and non-toxic first-row metals have emerged as versatile and sustainable alternatives to conventional solvents/promoters in a variety of synthetic organic protocols under greener and milder reaction conditions. In particular, Fe(III)-based Lewis Acidic DESs (LADESs) have recently shown great potential as dual solvent/promoter systems enabling efficient transformations under air and recyclable conditions without requiring toxic volatile organic compound (VOC) solvents at any stage in the protocol (synthesis, isolation or purification). Specifically, in this short review, we summarize our recent progress in the application of FeCl3-based DESs as sustainable and efficient promoters/solvents in organic synthesis by presenting two representative examples: i) the hydration and hydration/oxidation of terminal or internal alkynes to yield methyl ketones or 1,2-diketones, respectively; and ii) the Friedel-Crafts benzylation reaction. The performance, recyclability, mechanistic features and green metrics for these processes are discussed, highlighting the promise of this approach for sustainable synthesis.

Formaldehyde (FA) is a widely used yet highly toxic volatile organic compound that poses significant health hazards, necessitating the development of rapid, sensitive, and selective detection platforms. Here, we report a novel colorimetric sensor that integrates a rhodamine-based compound (RhB-HZ) into 3D printed structures for the visual and optical detection of FA. A spirolactam-structured rhodamine derivative was synthesized and embedded within a photocurable PEGDA/HEMA resin, allowing direct fabrication of sensor discs and optical probes using digital light processing 3D printing. Upon exposure to FA, the probe undergoes a selective ring-opening reaction, yielding a vivid pink color and reduced transmission at 562nm, with high specificity and a linear response across relevant concentrations and potential interferents. The lower detection limit (LOD) of RhB-HZ for FA detection is 0.0261ppm, below the World Health Organization (WHO) limits. Furthermore, smartphone-based readout enabled portable, cost-effective detection through image analysis of transmitted laser light. This work presents the first demonstration of a 3D-printed sensor specifically designed for trace-level formaldehyde detection related to food spoilage, an unexplored approach in the field. The discs visually indicate freshness in meats like chicken, sardines, and prawns inside sealed packages, offering a scalable, customizable, and adaptable platform for FA and other analyte detection in smart food monitoring. Further, a colorimetric INHIBIT logic gate was constructed using RhB-HZ, enabling binary detection of formaldehyde and sulfide through input-dependent absorbance changes at 562nm.

Solvents are indispensable in industrial and consumer applications, yet conventional solvents, often comprising toxic volatile organic compounds (VOCs), pose significant risks to environmental and human health. The urgent need for sustainable alternatives has driven the development of green solvents, characterized by low toxicity, biodegradability, and alignment with green chemistry principles. This review conducts a comprehensive bibliometric analysis of 21.991 articles on green solvents published in the ScienceDirect database from 2010 to 2025, utilizing VOSviewer to map publication trends, journal distributions, subject areas, and keyword relationships. The analysis reveals a surge in publications since 2020, with approximately 80% of studies concentrated between 2010 and 2025, reflecting global sustainability priorities such as the UN Sustainable Development Goals and EU regulations on VOC emissions. This study critically synthesizes the literature, comparing green solvent types—water, supercritical fluids (CO2 and ethanol), ionic liquids (ILs), deep eutectic solvents (DESs), and bio-based solvents—and their applications in chemical synthesis, pharmaceuticals, biotechnology, nanotechnology, and environmental remediation, including heavy metal and dye removal. By analyzing highly cited works and publication trends, it addresses the question: “What makes green solvents promising for sustainable chemical processes, and what barriers must be overcome to realize their full potential?” The review identifies key challenges, such as scalability, cost, and lifecycle impacts, and proposes targeted research directions, including lifecycle assessments (LCAs), interdisciplinary applications, hybrid solvent systems, and policy frameworks, to advance green solvent development and align with global sustainability goals.

The detection of volatile organic compounds (VOCs) released during spoilage is crucial for monitoring food quality and safety in storage and transportation. These VOCs serve as key indicators of microbial activity and chemical degradation, making them essential targets for gas-sensing applications. Various materials, including metal oxides and polymer-based composites, have been explored for their ability to detect spoilage-related VOCs due to their sensitivity and selectivity [1]. However, the efficiency of these sensors depends on factors such as surface properties, defect states, and adsorption mechanisms. This study employs Density Functional Theory (DFT) to systematically investigate the interaction of VOCs with sensing materials, focusing on the role of surface modifications and defects in enhancing sensor performance. Understanding these mechanisms will aid in the development of highly sensitive and selective sensors for real-time spoilage detection [2].This study investigates the ZnO (100) surface for its ability to detect various toxic volatile organic compounds (VOCs) released during spoilage. The findings suggest that the ZnO (100) surface exhibits selectivity toward ethanol and acetone gases. Structural analysis of the ZnO (100) surface determined lattice constants of a = 3.263 Å and c = 5.235 Å, with a unit cell volume of 48.30 ų. The adsorption energy of ethanol on the ZnO surface was calculated as -94.45 eV, indicating a strong and favorable interaction. The ethanol molecule interacted with the surface via the hydroxyl group site, drawing +1.27e of charge from the surface. The ethanol gas exhibits a high adsorption energy on the surface, making its desorption more challenging. Consequently, elevated temperatures are required to facilitate gas desorption. To address this and lower the operating temperature of the gas sensor, we propose the development of a ZnO/CuO heterostructure. In this study, we employed the CuO(111) surface to examine gas adsorption behavior, where ethanol showed an adsorption energy of -1.75 eV on the heterostructure. The analysis of adsorption energy, bond length alterations, and structural parameters offers a comprehensive understanding of interaction dynamics at the molecular level, which is crucial for advancing sensor technology in monitoring air quality and detecting hazardous gases. Figure 1

Technological advances in solvents drive a significant decrease in VOC emissions and negative impacts from industrial solvent-use sources.

The aim of this study was to evaluate changes in tooth color and the bond strength of resin to enamel and dentin after exposure to electronic cigarette (e-cigarette) vapor in an in vitro vaping model, as well as to analyze the chemical composition of the materials present in the vapor. A device with a vacuum pump simulated vaping. Eighty dental slabs (40 dentin and 40 enamel) and were randomly divided into two groups. Half received e-cigarette exposure, and the other remained without vaping (control). Color changes were measured using a spectrophotometer (CIELAB). Composite cylinders were built on substrates using etch-and-rinse or self-etch strategies and subjected to loading tests. Gas chromatography-mass spectrometry (GC-MS) analyzed the organic compound of the e-liquid, while inductively coupled plasma mass spectrometry (ICP-MS) assessed the metal content. Statistical analysis was conducted using MANOVA and ANOVA (α = 0.05), and CIEDE2000 formula. E-cigarette exposure darkened (L*) and yellowed (b*) enamel and dentin. Bond strength in dentin decreased for both adhesion strategies, and in enamel using the etch-and-rinse adhesive. GC-MS identified 72 different volatile compounds, whereas ICP-MS detected 26 distinct metals. Among metals, eight exceeded the WHO (World Health Organization) tolerance limits. E-cigarette exposure altered the color of substrates and reduced resin bond strength in dentin for both adhesives, and in enamel restored with the etch-and-rinse technique. E-liquid had toxic organic compounds and metals. Exposure to e-cigarette can cause tooth discoloration and weaken bonding to dental tissues. Toxic volatile organic and metallic compounds present in vapor can adversely affect oral health.

Bacterial diseases of Pleurotus pulmonarius, caused by diverse pathogens and associated with a range of symptoms, reduce its commercial value and lead to substantial economic losses. While most research has focused on Pseudomonas tolaasii and its non-volatile toxin tolaasin, little is known about other bacterial pathogens and their volatile metabolites. In this study, two bacterial pathogens were isolated from symptomatic P. pulmonarius fruiting bodies in Guangxi, China, and identified as Ewingella americana and Cedecea neteri. Using headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS), we identified 16 volatile organic compounds (VOCs) produced by these two species, seven of which exhibited toxicity-inducing sunken lesions, discoloration, and inhibition of mycelial growth. Symptom severity was quantified by colorimetric analysis. Among the toxic VOCs, 2,4-di-tert-butylphenol was the most potent, inducing sunken lesions and slight discoloration at concentrations as low as 0.5 mg/mL, and causing significant inhibition of mycelial growth at 5 μg/L. The remaining VOCs also caused varying degrees of sunken lesions, yellowing or browning, and suppression of mycelial growth. This study is the first to demonstrate the pathogenic potential of VOCs produced by bacterial pathogens in P. pulmonarius, underscoring their role as important virulence factors and providing a foundation for further investigation into their mechanisms and control strategies.

High photodegradation of toxic volatile organic compounds by biochar derived Cu doped BiHCC nanocomposites

The capacity of indoor plants including green walls to capture, deposit and remediate individual volatile organic compounds (VOCs) has been well documented. However, in realistic settings, plant systems are exposed to a complex mixture of VOCs from highly varied various emission sources. Gasoline vapour is one of the major sources of these emissions, containing high concentrations of the carcinogens benzene, toluene, ethylbenzene and xylene (BTEX). Using both solid phase micro extraction (SPME) and quick, easy, cheap, effective, rugged and safe (QuEChERS) sampling techniques, we assessed the dynamics of individual speciated gasoline VOC phytoremediation from the air and uptake within green wall plant species and growth substrates within a small passive green wall system, along with quantifying the phenotypic changes within the plant-associated bacterial communities resulting from gasoline exposure. Over 8 h the green wall system achieved 100% removal of atmospheric benzene, 1,2,3-trimethyl, eicosane and hexadecane, benzene 1,3-diethyl-; 1,3,5 cycloheptatriene,7- ethyl and carbonic acid eicosyl vinyl ester. All plant species tested demonstrated the accumulation 45 petrochemical VOCs (pVOCs) with Spathiphyllum wallisii successfully accumulating the majority of pVOC functional groups after 24 h of gasoline exposure. Within the plants phyllospheric bacterial communities, changes in both cellular complexity and granularity appeared to increase as a result of gasoline exposure, while cell size diminished. This work provides novel findings on the VOC removal processes of botanical systems for realistic and highly toxic VOC profiles.

Rajasthan, experiencing rapid industrialization and urbanization, faces critical air quality challenges, particularly concerning toxic volatile organic compounds (VOCs) such as BTEX (Benzene, Toluene, Ethylbenzene, Xylene). This study presents a long-term analysis of BTEX concentrations across various cities in Rajasthan, India, using data from the Central Pollution Control Board (CPCB) from 2017 to 2022. The findings revealed that the average ∑BTEX concentrations increased from 4.15 µg/m3 in 2017 to 12.29 µg/m3 in 2022, with a temporary decline in 2020. The Hazard Quotient (HQ) values for BTEX exposure ranged from 0.052 to 0.15 for males, 0.056 to 0.17 for females, and 0.09 to 0.29 for children over the study period, indicating higher health risks for children. Similarly, the Lifetime Cancer Risk (LCR) values varied from 6.04 × 10⁻⁶ to 1.92 × 10⁻5 for males, 1.09 × 10⁻⁶ to 2.24 × 10⁻5 for females, and 1.17 × 10⁻5 to 3.73 × 10⁻5 for children. The results demonstrate that children are at a greater cancer risk from BTEX exposure compared to adults. This study emphasizes the urgent need for effective air pollution control measures and continuous monitoring to protect public health, particularly vulnerable populations like children.

ABSTRACT Styrene butadiene styrene (SBS) is widely used to enhance asphalt pavement performance. When road fires occur, asphalt quickly undergoes pyrolysis, releasing toxic volatile organic compounds (VOCs) that threaten life security. Many previous studies investigate the SBS modifier’s impact on mechanical characteristics, while quite rare of them address the pyrolysis kinetics with VOC formation of the SBS-modified asphalt, particularly when they experience thermally aged process. This study has applied the thermogravimetry-mass spectrometry technique (TG-MS) and distributed activation energy model (DAEM) to address these research gaps. Our analytical results present that the thermal stability of the SBS-modified asphalt (SBSMA) is significantly promoted with 5% higher activation energy (E) than that of unmodified asphalt (UMA), mainly attributed to the heat absorption of the SBS modifier which results in a slow temperature rise of asphalt. However, the VOC emissions of SBSMA are nearly 190% higher than those of UMA, which is owing to the thermal decomposition of the SBS modifier. Besides, thermally aged asphalt emits approximately 40% fewer VOCs than fresh asphalt, indicating that the organic-compositional loss occurs during the aging process. This work provides fundamental insights into asphalt combustion and alerts designers to re-design SBS-asphalt owing to its dramatic pyrolysis-generated VOC emissions.

Abstract Vapor intrusion of toxic volatile organic compounds (VOCs) from subsurface soil vapor, through a building slab/floor, and into the indoor air is an important environmental contaminant transport mechanism. It is widely believed that advective flow, driven by the pressure differential between the subslab and indoor air, is the primary mechanism of subslab soil vapor entry into buildings. This paper explores the hypothesis that molecular diffusion through the slab may potentially play a larger role in vapor intrusion than previously believed and may even be the predominant vapor intrusion mechanism when the subslab vapor source strength is sufficiently high or the pressure differential is relatively low. A novel sampling device, referred to as a Passive Adsorptive Diffusion Sampler (PADS), is presented for the purpose of directly measuring the diffusion of VOCs through a building slab. A vacant warehouse was identified as a case study site where historical sampling had determined that vapor intrusion of trichloroethene (TCE) was adversely impacting the indoor air. Calculations using Fick's First Law of Diffusion are presented which demonstrate that diffusion alone can theoretically account for all the TCE observed in the indoor air at this building based on an effective diffusion coefficient for concrete that was calculated from the Johnson and Ettinger Model. Two groups of nine replicate PADS were deployed at two areas on the slab and used to measure the flux and effective diffusion coefficient at each of the 18 total points, which showed an order of magnitude variability within each area and over two orders of magnitude variability overall. These results indicate that diffusion through concrete is inherently variable when measured at a sub‐meter scale. However, when combined over both areas, the overall average approached that calculated from the Johnson and Ettinger Model. An additional 12 PADS were deployed across the building slab (for a total of 30) to quantify the overall building‐wide diffusive flux. This area‐weighted average diffusive flux was consistent with the predicted diffusive flux as calculated from Fick's First Law and the vapor intrusion mass input required to achieve the observed indoor air TCE concentration. The results of this study show that PADS provides a simple way to measure diffusive flux directly without having to drill through the slab. However, significant variability in the measured flux should be expected and will need to be accounted for by the inclusion of a relatively large number of samples including replicates. When using PADs at a new site, the collection of traditional subslab vapors at a select number of locations is recommended for the verification of a building‐specific effective diffusion coefficient, which may not necessarily be the same as for this building.

Health risks to workers involved in the active pit excavation of volatile organic compound (VOC)-contaminated soils have been overlooked, despite the prevalence of ex-situ remediation practices in China. This study developed a new VOC exposure in pit excavation (VEPE) model that comprehensively accounts for the release of gas-phase VOCs in soil pores, surface volatilization of newly exposed agglomerates, and volatilization of newly exposed excavation pit bottom surfaces. Additionally, the model incorporates the concentration variation of soil contaminants, spatial heterogeneity of soil properties, and the variability and uncertainty of worker exposure using two-dimensional Monte Carlo simulation (2D MCS), highlighting the importance of controlling area of new exposure surfaces, soil saturation, and air exchange during the pit excavation to mitigate risks. The study evaluated worker-health-based risks during the excavation of a VOC-contaminated site in Beijing and revealed that the inhalation cancer risk for trichloroethylene (2.35 × 10−6) and its hazard quotient (143.92) exceed the acceptable levels (10−6 and 1.0, respectively). The comparison of models demonstrated the theoretical advancements of the VEPE model over existing pit excavation models, while the field test comparison showed a significant improvement in the predication accuracy. This study addresses the under-researched area of worker safety in contaminated excavation sites. The findings have the potential to promote cleaner and more sustainable practices in ex-situ contaminated site remediation by providing valuable insights for implementing effective control measures to mitigate the emission of toxic VOCs, thereby reducing adverse social and environmental impacts.

Rapidly photocatalytic degradation of toluene boosted by plasmonic effect and Schottky junction on Pt nanoparticles engineered self-supporting Cu2O nanowires

In the present work, we examined the sensing behavior of monolayer beta antimonide phosphorus (β-SbP) sheets towards toxic volatile organic compounds (VOCs) namely, 1,2-diethylbenzene and 2-ethyltoluene using density functional theory (DFT) method. At first, using cohesive energy structural stability of the monolayer β-SbP is confirmed. The calculated energy band gap value of monolayer β-SbP is 2.168eV, which is a semiconductor. Furthermore, the adsorption properties of 1,2-diethylbenzene and 2-ethyltoluene on β-SbP are studied through key factors, such as adsorption energy, Mulliken charge transfer, and relative band gap variation. The adsorption energy clearly shows (- 0.335 to - 0.903eV) that both 1,2-diethylbenzene and 2-ethyltoluene are physisorbed on β-SbP monolayer. Besides, Mulliken charge transfer falls in the range of - 0.465 to 0.933 e; this information clearly shows that the β-SbP monolayer is a potential candidate for sensing 1,2-diethylbenzene and 2-ethyltoluene molecules. The structural firmness including electronic and adsorption properties of 1,2-diethylbenzene and 2-ethyltoluene on β-SbP monolayer are investigated with the support of the DFT method. Particularly, the hybrid generalized gradient approximation (hybrid GGA) along with Beck's three-parameter + Lee-Yang-Parr (B3LYP) exchange-correlation functional is utilized for relaxing the β-SbP monolayer. In the present work, all calculations are performed using the Quantum Atomistic Tool Kit (ATK) simulation package. In the present work, we utilized β-SbP monolayer as a chief sensing element to detect 1,2-diethylbenzene and 2-ethyltoluene to safeguard humans from toxic environments.