Search Results (6,473)

Ghost nets are the result of fishing nets ending up at sea by fishing vessels during operations, repairs, accidental loss, and from aquaculture activities. This is a major threat to the marine environment due to the entrapment of marine species, which often leads to the mortality of important species, the alteration of the marine benthic habitat, and the release of microplastics. In the current study, the authors conducted underwater clean-up activities in the marine protected area of Sounio in Greece (NATURA2000) to identify, evaluate whether they can be removed, and remove ghost nets. A total of 1200 Kg of ghost nets was removed within one year, with 68 different species reported to have colonized the nets. The reported groups were Mollusca, Porifera, Chordata, Arthropoda, Echinodermata, Bryozoa, Ochrophyta, Tracheophyta, Rhodophyta, Cnidaria, Chlorophyta, and Annelida. The species were not listed as threatened by the IUCN conservation status, while 86% were native, and 14% were invasive in the Mediterranean Sea. The current work presents the need to expand research efforts in the field of underwater plastic pollution, implement monitoring campaigns to a greater extent in the study area, and perform an assessment before the removal of ghost nets. Full article

A promising route for removing antibiotics such as penicillin from wastewater is photocatalytic degradation under UV irradiation using TiO₂ nanoparticles. However, the microscopic mechanisms governing the initial degradation steps remain poorly understood. In particular, it is still unclear whether degradation preferentially occurs in solution or upon adsorption on the oxide surface, and which molecular sites are most vulnerable to attack in solution compared to those activated on the catalyst. In this work, we introduce a unified density functional theory approach that treats penicillin V (phenoxymethylpenicillin) consistently, both isolated in solution and adsorbed on an anatase TiO₂ nanocluster, enabling a direct comparison between solution-phase and surface-mediated degradation pathways. Within this framework, we analyze the adsorption configurations, energy-level alignment, charge-transfer pathways, UV-Vis absorption properties, local reactivity descriptors, and the initial steps leading to bond breaking. The results show that the direct photoexcitation of PenV followed by electron transfer to the oxide is less likely, due to the high energy of the pollutant’s excited states. In contrast, degradation initiated by the transfer of photogenerated holes from the catalyst to the adsorbed antibiotic appears more probable, driven by the smaller energetic offset and by the hybridization between molecular and oxide states. Overall, adsorption on the oxide surface appears to be more conducive to degradation, with the carbon atom in the β-lactam ring consistently identified as a susceptible site for attack across different environments. Full article

Pollen allergy represents a growing public health concern, yet the role of microplastic pollution in modulating allergen behavior remains largely unresolved. In this study, we investigated interactions between polyethylene terephthalate (PET) microplastics (0.2–12 µm; predominantly 0.4–1 µm) and cedar pollen proteins, with emphasis on the major allergen Cry j 1. Surface charge characterization using the pH drift method revealed two apparent points of zero charge in the acidic (pH 3.0–3.8) and near-neutral (~7.5) regions, indicating surface chemical heterogeneity. Protein adsorption experiments conducted at physiological pH (7.4) showed concentration-dependent and saturable removal of proteins from solution with increasing PET mass and a 3.10-fold preferential enrichment of aromatic-rich protein fractions. Spectroscopic analyses revealed adsorption-induced but non-denaturing structural perturbations, including increased exposure of aromatic residues and partial β-sheet destabilization. Complementary all-atom molecular dynamics simulations showed rapid and stable Cry j 1 adsorption onto PET, anisotropic surface accommodation, modest increases in solvent accessibility, and subtle secondary structure rearrangements without global unfolding. Together, these findings indicate that PET microplastics can selectively bind and structurally modulate pollen allergens in ways that may influence allergen persistence and epitope presentation, with potential implications for IgE-mediated sensitization in polluted environments. Full article

Sewage sludge management is a major challenge in modern wastewater treatment, as sludge contains organic matter, nutrients, pathogens, heavy metals, and emerging contaminants. Increasing wastewater volumes from urbanization and population growth have led to steadily rising global sludge production, emphasizing the need for sustainable and resource-efficient treatment strategies. Conventional methods—such as landfilling, land application, and biological treatment—face limitations due to contaminant risks, regulatory restrictions, and incomplete pollutant removal. Thermal and thermochemical processes offer substantial volume reduction, energy recovery, and resource valorization. Incineration is widely implemented and ensures complete oxidation but requires high energy input and emission control. Gasification and pyrolysis produce syngas, bio-oil, and biochar, supporting circular economy applications, while hydrothermal carbonization (HTC) efficiently converts wet sludge into hydrochar without intensive drying. This study presents a comparative life cycle assessment (LCA) and mass–energy assessment of these four thermal treatment methods, highlighting their environmental impacts, energy efficiencies, and resources’ recovery potential to support more sustainable sludge management. Full article

Advanced oxidation processes using porphyrin-based heterogeneous catalysts hold promise for removing hazardous pollutants from wastewater. Their high visible-light absorption coefficients enable absorption of light from the solar spectrum. Moreover, their conjugated aromatic skeletons and intrinsic electronic properties facilitate the delocalization of photogenerated electrons during photodegradation. Delaying the recombination of photogenerated electron–hole pairs by introducing specific materials increases efficiency, as separated charges have more time to participate in redox reactions, boosting photocatalytic activities. However, applying these photocatalysts for wastewater treatment is challenging owing to facile agglomeration, deactivation, and recovery of the photocatalyst for reuse, which can significantly increase the overall cost. Therefore, new photocatalytic systems comprising porphyrin molecules must be developed. For this purpose, porphyrins can be conjugated to nanomaterials to create hybrid materials with photocatalytic efficiencies superior to those of free-standing starting porphyrins. Various transition metal oxides (TiO₂, ZnO, and Fe₃O₄) nanoparticles, main-group-element oxides (Al₂O₃ and SiO₂) nanoparticles, metal plasmons (silver nanoparticles), carbon-based platforms (graphene, graphene oxide, and g-C₃N₄), and polymer matrices have been used as nanostructured solid supports for the successful fabrication of porphyrin-conjugated hybrid materials. The conjugation of porphyrin molecules to solid supports improves the photocatalytic degradation activity in terms of visible-light conversion ability, recyclability, active porous sites, substrate mobility, separation of photogenerated charge species, recovery for reuse, and chemical stability, along with preventing the generation of secondary pollution. This review discusses the ongoing development of porphyrin-conjugated hybrid nanomaterials for the heterogeneous photocatalytic degradation of organic dyes, pharmaceutical pollutants, heavy metals, pesticides, and human care in water. Several important results and advancements in the field allow for a more efficient wastewater remediation process. Full article

In fire and emergency rescue operations, visibility is often severely degraded by smoke, airborne debris, or atmospheric pollutants including smog and yellow dust. Several image restoration techniques, including Dark Channel Prior (DCP), Color Attribution Prior (CAP), Peplography, and Adaptive Removal via Mask for Scatter (ARMS), have been proposed to recover clear images under such conditions. However, these methods exhibit significant limitations in heavy scattering environments. This paper proposes a novel visibility restoration method for disaster situations, building upon the state-of-the-art ARMS method. To maximize the suppression of scattering effects, the Scattering Media Model is refined through Gaussian estimation. Additionally, an overlapping matrix is introduced to effectively handle non-uniformly distributed scattering conditions. The proposed method is evaluated using a real rescue operation image dataset provided by the Fire and Disaster Management Agency of Japan. Qualitative visual assessments and quantitative performance metrics demonstrate that the proposed approach significantly outperforms conventional methods under severe scattering conditions. Full article

This work reports the synthesis and photocatalytic performance of TiO₂–MgO/kaolinite nanocomposites for the degradation of crystal violet (CV) and butyraldehyde under UV irradiation. MgO incorporation enhanced charge separation by limiting electron–hole recombination, while the halloysite-type kaolinite support increased surface area and improved dispersion of the active phases. The materials exhibited strong synergy between adsorption and photocatalysis, as the clay support pre-concentrated pollutants and facilitated their rapid degradation. The composite containing 10 wt% MgO (TK10) showed the highest efficiency, achieving 99.8% CV removal and outperforming commercial P25. The catalyst also demonstrated efficient degradation of gaseous butyraldehyde, highlighting its dual applicability for water and air purification. Kinetic analysis indicated a pseud-second-order adsorption mechanism, and isothermal data fitted the Langmuir model, suggesting monolayer adsorption. The TK10 composite showed excellent stability and reusability over multiple cycles, underscoring its potential as a cost-effective and environmentally benign photocatalyst for integrated environmental remediation. Full article

Rapid urbanization has fostered the proliferation of urban villages (UVs), high-density informal settlements that pose unique challenges for environmental management. Despite their prevalence, the dynamics of pollutant accumulation in these transitional neighborhoods remain underexplored. This study investigated nitrogen and phosphorus accumulation in road-deposited sediment (RDS) within Shenzhen, a representative megacity in southern China, utilizing field sampling and statistical analysis to identify dominant drivers. The results indicate that UVs function as significant pollution hotspots, with RDS accumulation rates approximately 3.7 times higher than in formal built-up areas. Analysis revealed that pollution intensity is primarily driven by natural factors such as slope, whereas pollution load is controlled by anthropogenic supply factors. This creates a critical input–output imbalance where high pollutant inputs exceed the natural removal capacity. Consequently, effective mitigation of urban non-point source pollution requires shifting from traditional engineering solutions to spatially sensitive planning strategies, offering practical guidance for enhancing urban sustainability in rapidly urbanizing regions. Full article

The problem of urban surface runoff (USR) treatment is associated with the presence of high concentrations of specific pollutants. One of these pollutants is petroleum product (PP), whose concentration depends on the season and the location of the formation of snow masses, meltwater, and rainwater. For USR treatment, it is possible to use very environmentally friendly and inexpensive technologies. The article discusses natural sorbents based on wood materials, which effectively remove dissolved petroleum products from water. Pine sawdust and shredded branches of maple, birch, and poplar are used as raw materials, which are waste products from the city’s woodworking enterprise and utilities. These materials were pre-microwave (MW) treated to improve their sorption properties. As a result of the experiment, it turned out that modified pine sawdust and crushed maple pinwheels proved to be the most effective sorbents. The maximum sorption capacity values were 0.689 mg/g and 0.952 mg/g for pine and maple sorbents, respectively. This article proposes schemes for filtering devices that can be used in practice in an urban environment. Full article

The presence of emerging contaminants in water has led to a need for the development of new materials and treatments. Four low-cost adsorbents derived from lignocellulosic biomass waste (pine nut shells and olive stones) were prepared via chemical treatment (with H₃PO₄ or NaOH) followed by thermal activation (at 550 °C under N₂). Characterization of the bioadsorbents was carried out using N₂ adsorption–desorption isotherms, FTIR and Raman spectroscopic analyses, and pHpzc determination. The electrostatic interactions between the adsorbent surface and the dyes were determined, and it was found that the interactions in both adsorbents were attractive for the methylene blue and repulsive for methyl orange, at pH basic or neutral. The performance of the obtained activated carbons was evaluated at lab scale with two dyes (methylene blue and methyl orange), and a comparison was made between both adsorbents and with commercial charcoal. The H₃PO₄-activated adsorbents exhibited higher adsorption capacities (up to 300 mg/g for methylene blue and 285 mg/g for methyl orange), with adsorption efficiencies close to 100%. More than 10 adsorption–desorption cycles were performed, with efficiencies exceeding 85%. The good reusability shown by the H₃PO₄-activated adsorbents suggests significant potential for industrial application; namely, in the removal emerging contaminants from urban wastewater. It should be noted that the adsorption efficiency decreased after the fifth cycle, indicating a gradual reduction in performance over time (although it remained above 85% in the performed experiments). This study aims to achieve the goal of zero waste and contribute to the circular economy through the sustainable use of residual biomass. Full article

In the context of global warming mitigation through energy conservation and pollution control, integrating green waste into treatment processes has become more popular. This study evaluated the potential of raw wood processing residues generated from furniture manufacturing as renewable sorbents for water treatment. Comparative studies assessed the Mn(II) removal efficiency of raw walnut (WW) and cherry (CW) wood shavings and the derived biochars (BChWW, BChCW) produced by hydropyrolysis. SEM, BET, FTIR, and TGA analyses characterized their surface and structural properties. CW demonstrated a higher adsorption capacity compared to WW. Physical activation enhanced the surface properties and Mn(II) adsorption affinity of the materials. Maximum adsorption capacities ranged from 2.1 to 2.2 mg/g for CW and WW, and 2.4 to 2.5 mg/g for BChCW and BChWW. The Freundlich model best fits to the data obtained using CW (R² = 0.997) and BChCW (R² = 0.984), while the RALF isotherm almost perfectly describes the mechanism of the Mn(II) adsorption onto WW (R² = 0.999) and BChWW (R² = 1.000). The pseudo second-order kinetic model shows strong agreement with experimental data, which suggests chemisorption on a heterogeneous surface. The results underscore the potential of wood industry byproducts as efficient and low-cost adsorbents for water treatment, supporting the circular economy and sustainable environmental management. Full article

The continuous emission of persistent and bioaccumulative pollutants into aquatic environments has become a critical global issue. Among these, per- and polyfluoroalkyl substances (PFASs) are of particular concern due to their exceptional stability, extensive industrial use, and adverse impacts on ecosystems and human health. Their resistance to conventional physical, chemical, and biological treatments stems from the strength of the carbon–fluorine bond, which prevents efficient degradation under standard conditions. This review provides a concise and updated assessment of emerging advanced oxidation processes (AOPs) for PFAS remediation, with emphasis on heterogeneous photocatalysis and electrochemical oxidation. Photocatalytic systems based on In₂O₃, Bi-based oxyhalides, and Ga₂O₃ exhibit high PFAS degradation under UV light, while heterojunctions and MOF-derived catalysts improve defluorination under solar irradiation. Electrochemical oxidation—particularly using Ti₄O₇ reactive electrochemical membranes and BDD anodes—achieves near-complete mineralization with comparatively low specific energy demand. Energy consumption (E_EO) was calculated from literature data for UV- and simulated-solar-driven photocatalytic systems, enabling a direct comparison of their energy performance. Although solar-driven processes offer clear environmental advantages, they generally exhibit higher E_EO values, mainly due to lower apparent quantum yields and less efficient utilization of the incident solar photons compared to UV-driven systems. Hybrid systems coupling photocatalysis and electro-oxidation emerge as promising strategies to enhance degradation efficiency and reduce energy requirements. Overall, the review highlights key advances and future research directions toward scalable, energy-efficient, and environmentally sustainable AOP-based technologies for PFAS removal. Full article

Solar advanced oxidation processes (AOPs) utilising parabolic trough concentrators (PTCs) present a promising approach for the sustainable removal of recalcitrant contaminants from wastewater. This mini-review critically evaluates 25 peer-reviewed studies employing PTC-AOP systems for the degradation of chemical pollutants and microbial pathogens. Reported applications include photolysis, photo-Fenton and photocatalysis for the treatment of synthetic dyes, contaminants of emerging concern, industrial effluents, heavy metals and pathogenic microorganisms. A performance-oriented comparison based on normalised indicators is introduced. The time required for one order-of-magnitude reduction (corresponding to 90% removal; τ₉₀) reveals a significant mineralisation setback, where parent-compound degradation outpaces total organic carbon removal. The PTC concentration ratio and photon utilisation metrics highlight substantial variability in reactor design (geometry, materials, optical performance), which directly influences the treatment kinetics. Overall, PTC-AOP systems demonstrate strong potential as a polishing step within hybrid wastewater treatment. Future research should prioritise the standardisation of performance metrics, the catalyst design suited for high-photon and -temperature operation, and the integration into scalable and climate-resilient solar wastewater treatment. Full article

Plastic has transitioned rapidly from a revolutionary material to a global environmental concern, primarily due to mismanagement. Synthetic polymers have quickly gained widespread use due to their versatility, durability, and affordability. However, the properties making plastic indispensable contribute to its permanence in the environment, where it breaks down into microplastics—tiny particles that are typically classified in the size range from 0.1 μm to 5 mm. These particles can now be found in all ecosystems, including the oceans, soil, atmosphere, and within living organisms, raising global concerns about their long-term environmental and health impacts. This review critically examines the current status and potential for identifying, analyzing, and mitigating microplastic pollution. In this paper, we particularly focus on the destructive and non-destructive analytical methods used for microplastic identification and characterization, examining their technical capabilities and limitations, the challenges in maintaining sample integrity, and the reliability of their quantification methods. In addition, the review addresses microplastic removal strategies, from laboratory procedures to real-world applications, examining barriers to implementation and the limited availability of existing solutions. Finally, the review highlights the urgent need for standardized protocols, regulatory frameworks, and interdisciplinary collaboration to address the multifaceted nature of microplastic pollution. Full article