Search Results (50)

The catalytic removal of refractory VOCs in gas–solid reactions usually suffers from the formation of toxic byproducts and catalyst deactivation. The advanced oxidation process (AOP) wet scrubber has recently attracted interest in VOCs purification due to its high efficiency and inhibited gaseous byproducts emission. MOFs/metal sulfides (termed M50C50) were designed to activate peroxymonosulfate (PMS) for toluene removal in a wet scrubber. The heterojunction interface synergistically couples MIL-100(Fe) and CoS for dual functions, the M50C50 enabled the rapid transfer the toluene from the gas phase to the aqueous phase, where they were subsequently mineralized by SO₄^•− and •OH radicals. The primary active sites responsible for PMS activation were identified as reducing sulfur species, along with low-valence cobalt and iron species. Over 90% of toluene were removed with a wide pH range, while •OH and SO₄^•− were involved in the mineralization of intermediates. The process showed high mineralization efficiency (75% CO₂ evolution) and effectively reduced the formation of toxic byproducts, underscoring its potential for minimizing secondary pollution risks. This work provides a novel route to designing composite catalysts for deep VOC oxidation via AOP wet scrubbers, greatly facilitating their use in environmental remediation. Full article

Volatile organic compounds (VOCs) from historical industrial activities can persist for decades, contaminating groundwater and the unsaturated zone, yet their transport through thick, heterogeneous vadose zones is poorly understood. This study reconstructs long-term migration of tetrachloroethylene (PCE) from a former industrial site in the Jerusalem Mountains, where leakage likely began ten years after plant commissioning and systematic monitoring started decades later. A three-dimensional numerical model of flow and transport was applied, incorporating calibrated hydraulic parameters, karstic conduits, and multiphase VOC processes including advection, dispersion, phase partitioning, volatilization, and first-order degradation kinetics. Multiple model runs explored plausible leakage scenarios under sparse historical data. Simulated PCE concentrations reproduce measurements in the vadose zone (R² = 0.89) and deep regional aquifer (~20% normalized relative error). Results reveal pronounced preferential flows horizontally through perched aquifers and vertically along discrete faults, amplified by karstic networks. The upper vadose zone remains a persistent source, sustaining gas-phase emissions toward nearby residential areas unless targeted remediation is applied. Integrated modeling, even with limited monitoring, quantitatively reconstructs complex contaminant dynamics across saturated and unsaturated compartments, providing critical guidance for remediation. Protecting groundwater and human health requires addressing both vadose and saturated zones to prevent prolonged environmental and exposure risks. Full article

This review focuses on the use of metal–organic frameworks (MOFs) for environmental remediation through adsorption processes in both liquid and gas phases. Due to their high surface areas and chemical tunability, MOFs offer promising performance in adsorbing environmental pollutants compared to traditional materials. In this work, we discuss advanced synthesis techniques, including solvothermal, room temperature, and mechanochemical techniques, and how each technique influences the resulting MOF’s structural properties. Furthermore, we analyze the use of MOFs as adsorbents for CO₂ and volatile organic compounds (VOCs) in the gas phase, as well as their role in removing heavy metals, fluorides, dyes, and emerging pharmaceutical contaminants. Although MOFs possess intrinsic limitations, such as instability in the presence of water and challenges in cyclic regeneration, their combination with other materials has aimed to overcome these drawbacks by leveraging the best properties of each component in new hybrid materials. Finally, we evaluate various challenges, such as large-scale implementation, toxicity, and long-term stability, proposing sustainable solutions for environmental remediation. Full article

Volatile organic compounds (VOCs) are major contributors to air pollution, posing significant environmental and health risks. Here we report gallium oxide (Ga₂O₃)-coated mesh as a practical immobilized photocatalyst for VOC degradation under UVC irradiation. A 3 wt.% Ga₂O₃ suspension was spray-coated onto the stainless-steel mesh, yielding a uniform coating with strong adhesion properties, as confirmed by cross-sectional analysis. Under identical conditions to a Ga₂O₃ powder, the Ga₂O₃-coated mesh delivered comparable VOC degradation rates and first-order kinetics while offering superior mechanical stability and ease of handling. Over five consecutive cycles, 93–95% of the VOC degradation efficiency was retained with negligible loss of activity, confirming excellent reusability. Fourier Transform Infrared Spectroscopy (FTIR) spectra of the Ga₂O₃-coated mesh after degradation reaction revealed significantly reduced VOC peaks, such as C=O and C-O absorption peaks, whereas spectra for the uncoated mesh changed only slightly. These results indicate that VOC degradation originates from the coated photocatalyst. Overall, these findings demonstrate that Ga₂O₃-coated mesh is a highly efficient, stable, and reusable platform for VOC removal, suggesting its potential for practical applications in air purification and environmental remediation. Full article

In global economic integration and rapid urbanization, the equilibrium between resource utilization efficiency and ecological preservation is confronted with significant challenges. Emerging contaminants have further exacerbated environmental pressures and posed threats to the ecosystem and human health. Metal–organic frameworks (MOFs) have emerged as a prominent area of research in ecological remediation, owing to their distinctive porous configuration, substantial specific surface area, and exceptional chemical stability. The Materials Institute Lavoisier (MIL) series (e.g., MIL-53, MIL-88, MIL-100, MIL-101, and MIL-125) has been shown to effectively promote the separation and migration of photogenerated carriers and significantly enhance the degradation of organic contaminants. This property renders it highly promising for the photocatalytic degradation of emerging contaminants. This paper provides a concise overview of the classification, synthesis methods, modification strategies, and application effects of MIL series MOFs in the removal of emerging contaminants. The advantages and limitations of MIL series MOFs in environmental remediation are further analyzed. Particularly, we offer insights and support for innovative strategies in the treatment of emerging contaminants, including POPs, PPCPs, VOCs, and microplastics, contributing to technological innovation and development in environmental remediation. Future development of MOFs includes the optimization of the performance of the MILs, reducing the high synthesis costs of MILs, applying MILs in real-environment scenarios, and accurate detection of degradation products of environmental pollutants. Full article

A VOC-contaminated shallow aquifer in an industrial site was investigated to evaluate its potential for natural attenuation. The shallow groundwater aquifer beneath the industrial site has been contaminated by dissolved volatile organic compounds (VOCs) such as trichloroethylene (TCE), cis-1,2-dichloroethylene (cis-DCE), and vinyl chloride (VC) for more than three decades. Monitoring and investigation were implemented during 2011–2024, aiming to propose future groundwater aquifer management strategies. This study included groundwater borehole investigation, well installation monitoring, hydraulic head measurements, slug tests, groundwater samplings, and microbial analyses. Microbial investigations identified the predominant group of microorganisms of Proteobacteria, indicating biodegradation potential, as demonstrated by the presence of cis-DCE and VC. BIOSCREEN was used to evaluate the process of natural attenuation, incorporating site-specific parameters. A two-layer groundwater flow model was developed using MODFLOW with hydraulic conductivities obtained from slug tests. The site has an average hydraulic head of 259.6 m amsl with a hydraulic gradient of 0.026, resulting in an average groundwater flow velocity of 11 m/y. Hydraulic conductivities were estimated during model calibration using the PEST pilot point technique. A reactive transport model, RT3D, was used to simulate dissolved TCE transport over 30 years, which can undergo sorption as well as biodegradation. Model calibration demonstrated a satisfactory fit between observed and simulated groundwater heads with a root mean square error of 0.08 m and a correlation coefficient (r) between measured and simulated heads of 0.81, confirming the validity of the hydraulic conductivity distribution. The TCE plume continuously degraded and gradually migrated southward, generating a cis-DCE plume. The concentrations in both plumes decreased toward the end of the simulation period at Source 1 (located upstream), while BIOSCREEN results confirmed ongoing natural attenuation primarily by biodegradation. The integrated MODFLOW-RT3D-BIOSCREEN approach effectively evaluated VOC attenuation and plume migration. However, future remediation strategies should consider enhanced bioremediation to accelerate contaminant degradation at Source 2 and ensure long-term groundwater quality. Full article

Groundwater remains a critical water source for urban communities, particularly in rapidly urbanizing countries such as the Philippines. However, intensifying anthropogenic pressures have contributed to widespread contamination from heavy metals, nutrients, pathogens, volatile organic compounds (VOCs), and emerging pollutants, including pharmaceuticals and personal care products (PPCPs). This review synthesizes findings from 130 peer-reviewed studies on groundwater monitoring and remediation, emphasizing technological advancements and their application in urban environments. The literature is categorized into five thematic areas: monitoring technologies, contaminant profiles, remediation strategies, Philippine-specific case studies, and alignment with global frameworks. Recent innovations—such as Internet of Things (IoT)-enabled systems, remote sensing, biosensors, and artificial intelligence/machine-learning (AI/ML) models—show strong potential for real-time and predictive monitoring. Despite these advancements, technology adoption in the Philippines remains limited due to regulatory, technical, and infrastructural constraints. This review identifies key research and implementation gaps, particularly in the monitoring of emerging contaminants and the integration of data into policy-making and urban planning. To address these challenges, a conceptual framework is proposed to support more sustainable, technology-driven, and context-sensitive groundwater management in heavily urbanized areas. Full article

Aromatic volatile organic compounds (VOCs) pose significant environmental and public health risks due to their toxicity, carcinogenicity, and role as precursors of hazardous secondary pollutants. Zeolite-based metal catalysts, with their well-defined microporous structures, tunable acidity, and high thermal stability, have shown promise in the catalytic oxidation of aromatic VOCs. However, the influence of the zeolite microenvironment on supported metal active sites remains insufficiently understood, limiting the rational design of advanced catalysts. This review highlights how microenvironmental parameters—including pore architecture, acid site distribution, framework composition, and surface/interface engineering—can be modulated to enhance adsorption, oxygen activation, and metal–support interactions. Advances in hierarchical porosity, heteroatom substitution, and surface hydrophobicity are discussed. This review provides a framework for the development of next-generation zeolite-based catalysts and offers strategic guidance for advancing microenvironment-controlled catalysis in sustainable environmental remediation. Full article

This study explored how pore size engineering in Nb-Mn/MCM-41 catalysts affects plasma-catalytic toluene oxidation. Adjusting the pore diameter (2.49–3.98 nm) modulated metal-support interactions and oxygen dynamics, with pore expansion to 3.73 nm (M3) optimizing the Mn⁴⁺/(Mn²⁺ + Mn³⁺) ratio (XPS: 36.8%), the amount of lattice oxygen species (O₂-TPD: 0.222 mmol/g), and crystallite size control (1.5 ± 0.2 nm, TEM). Smaller pores (M1: 2.49 nm) enhanced toluene adsorption but limited active site accessibility, while oversized pores (M4: 3.98 nm) reduced oxygen storage capacity (0.600→0.412 mmol/g). The Nb-Mn/M3 catalyst achieved superior performance with 96.8% toluene conversion, 55.0% CO₂ selectivity, and 85.4% carbon balance, while minimizing organic byproducts (GC-MS). Mechanistic studies revealed pore-mediated oxygen storage-transport cycles as critical for decoupling adsorption and oxidation steps. This study reveals fundamental mechanisms linking pore architecture to plasma-catalytic synergy in toluene oxidation, offering critical insights for the systematic design of energy-efficient, plasma-catalytic systems targeting industrial VOCs remediation. Full article

Soil organic pollution poses a significant threat to agricultural safety in China, underscoring the critical importance of developing efficient remediation technologies for soil environmental protection. Steam injection, a promising method for removing organic pollutants from soil, has yet to be thoroughly investigated in terms of its energy efficiency. A novel steam injection system with horizontal wells is proposed to remediate soil xylene pollution, and a corresponding numerical model is established and solved through TOUGH2-T2VOC codes. The energy efficiency characteristics and main influencing factors of the system are analyzed. The results demonstrate that steam injection is an effective method to remediate xylene pollution. It is evaluated that during the first 1.5 years of the 5-year operation period, production xylene saturation gradually decreases from 0.3 to 0.05, and the production xylene mass flow rate gradually decreases from 0.179 kg/s to 2.448 × 10⁻⁴ kg/s. Pump power consumption gradually increases from 17.23 kW to 30.67 kW, while energy efficiency gradually decreases from 7.73 × 10⁻⁴ kg/kJ to 1.00 × 10⁻⁶ kg/kJ. Sensitivity analyses indicate that the main factors affecting the xylene mass flow rate are formation permeability, production pressure and the initial xylene saturation, and the main factors affecting energy efficiency are the steam injection flow rate, formation permeability, production pressure and initial xylene saturation. This has significant practical significance for the optimal design of the steam injection remediation scheme for soil organic pollution. Full article

With industrialization and widespread chemical use, soil organic pollutants have become a major environmental issue. Forest ecosystems, among the most important on Earth, have unique potential for controlling and remediating soil pollution. This article explores the mechanisms of microbial community degradation of organic pollutants, their adaptability across forest ecological conditions, and the effects of environmental factors on degradation efficiency. For example, acidic pH (pH < 5.5) favors PAH degradation, near-neutral pH (6.0–7.5) enhances pharmaceutical and PPCP degradation, and alkaline conditions (pH > 7.5) facilitate petroleum hydrocarbon, VOC, and PPCP breakdown. Optimal microbial degradation occurs with humidity levels between 60% and 80%, and SOM content of 2–5%. This review analyzes advancements in microbial degradation technologies for forest ecosystem soil pollution treatment, including genetic engineering, composting, bioaugmentation, and bio-stimulation techniques, and their integration with phytoremediation. The review also addresses the challenges of real-world implementation, such as maintaining microbial diversity, managing pollutant complexity, adapting to environmental changes, and highlighting future research opportunities. The next decade will focus on synthetic biology, omics technologies, microbial-electrochemical systems, community dynamics, eco-engineering, and plant-microbe synergy to develop efficient, sustainable bioremediation strategies. Full article

Since people spend most of their time in indoor environments, they are continuously exposed to various contaminants that threaten human health. The air quality in these settings is therefore a crucial factor in maintaining health safety. In order to reduce the concentration of indoor air pollutants and improve air quality, photocatalytic oxidation has drawn the attention of researchers. This study aims to provide a comprehensive view of the nanomaterials used in the photocatalytic oxidation of the most common pollutants in indoor environments. The effects of various parameters like humidity, airflow, deposition time, and light intensity were also evaluated, as they can significantly influence photocatalytic reactions. The most common nanomaterials used in photocatalysis are TiO₂-based and, in this study, they were classified and examined based on their morphology. TiO₂ doping with metals and non-metals has demonstrated an enhancement of its adsorption properties and photocatalytic efficiency for the removal of several pollutants. The role of carbon-based nanomaterials in photocatalysis was also evaluated due to their adsorption capabilities towards various pollutants. In addition, other less common photocatalysts such as ZnO, MnO₂, WO₃, CeO₂, and CdS also exhibited high photocatalytic activity for pollutant degradation. Applications of these photocatalysts in air purifiers, paints, and building materials e.g., concrete, glass, and wallpapers, lead to efficient reduction of pollutants in indoor settings. Full article

This study explores the synergistic interactions between photocatalysis, ozone treatment, and metal catalysts in the decomposition of acetaldehyde, a representative volatile organic compound (VOC). The study addresses the growing need for efficient air purification technologies by integrating advanced oxidation processes. Metal catalysts, particularly manganese oxide-based materials, were combined with photocatalysis and ozonation to investigate their impact on acetaldehyde removal efficiency. Experimental results revealed that the treatment integrating these methods significantly outperformed conventional single-process treatments. Metal catalysts facilitated the initial oxidation of acetaldehyde, while photocatalysis accelerated subsequent stages, including the mineralisation of intermediates. Ozone contributed additional reactive oxidative species, further enhancing decomposition rates. These findings provide valuable insights into the design of efficient VOC removal systems, demonstrating that integrating metal catalysts with photocatalytic and ozonation processes offers a promising strategy for improving air purification technologies. This approach has potential applications in environmental remediation and indoor air quality management. Full article

Biomass waste, generated globally in vast quantities, represents an underutilized yet highly valuable resource for advanced material production. This study highlights a novel valorization pathway for waste tangerine peels, sourced from Jeju Island, South Korea, by converting them into high-performance activated carbon (T-AC) with exceptional pore characteristics, specifically designed for volatile organic compound (VOC) removal. Utilizing a unique combination of hydrothermal carbonization (HTC) and dry carbonization (DC) processes, the structural properties of the biomass were optimized, significantly enhancing the fixed carbon content. Subsequent chemical activation with an alkaline agent yielded T-AC with an outstanding specific surface area (1530–3375 m²/g) and total pore volume (0.73–2.00 cm³/g), with a tailored pore distribution favoring the sub-mesopore range (2.0–4.0 nm). The T-AC demonstrated remarkable performance in removing methylene chloride (MC), a hazardous VOC, with methylene chloride activity (MA) increasing from 44.7% to 76.3% as the activation agent ratio increased, while methylene chloride working capacity (MWC) improved significantly from 17.1% to 55.9%. These results underscore the transformative potential of tangerine peel-derived AC as a sustainable solution for VOC remediation, combining environmental waste management with advanced adsorption technology. The findings not only advance the field of biomass utilization but also offer a scalable approach for tackling pressing environmental and industrial challenges. Full article

Air pollution has become one of the biggest problems throughout the world. Smog has a severe effect on the pulmonary and circulatory systems, which causes a significant number of deaths globally. Therefore, the remediation of air pollutants to maintain ecosystem processes and functions and to improve human health is a crucial problem confronting mankind today. This review aims to discuss the health effects of smog on humans. This review will also focus on the bioremediation of air pollution (smog) using bacteria, fungi, phytoremediation, nanotechnology, and phylloremediation (using plants and microbes). Phylloremediation is the most effective technology for removing air pollution naturally. The future perspective presents a great need to produce an ecosystem where microbes, plants, and nanoparticles synergistically control smog. In addition, further advancements would be needed to modify the genetic makeup of microbes and plants. Biotechnological approaches like CRISPR-Cas9 can be applied to the editing and cutting of specific genes responsible for the bioremediation of VOCs, NOx, SOx, and harmful hydrocarbons. The extracted genes can then be expressed in biologically modified microorganisms and plants for the enhanced bioremediation of smog. Full article