Natural zeolites, clinoptilolite from the Golobradovo deposit, Bulgaria, and mordenite from the Lyaskovets deposit in Eastern Rhodopes, Bulgaria, were used for the preparation of natural-zeolite-supported CeО₂@Polybenzimidazole (PBI) hybrid materials with green-synthesized ceria incorporated using Veronica officinalis L. plant extract. In order to prepare hybrid composite powders of the natural zeolites/green-synthesized CeО₂, the surface was impregnated with the use of ethanolic KOH solution of meta-polybenzimidazole as dispersant media. The chemical and phase composition, structure, and thermal behavior of the obtained composite materials were investigated through X-ray fluorescence analyses, powder X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The presence of CeO₂ (33.1 mass % and 32 mass %) in the prepared clinoptilolite- or mordenite-supported green-synthesized CeО₂@Polybenzimidazole was determined using X-ray fluorescence analysis. The photocatalytic properties of the synthesized hybrid materials were tested in the reaction of oxidative photocatalytic degradation of 5 ppm Reactive Black 5 (RB5) dye as a model pollutant under UV light irradiation. The photocatalytic results show that the RB5 dye demonstrates a higher degree of degradation (98%) with 120 minutes of UV irradiation in the presence of mordenite-supported/CeO₂@PBI as the photocatalyst compared to that with the clinoptilolite-supported/CeO₂@PBI (14%).

Acknowledgments: The authors express their gratitude to the project with the Bulgarian National Science Fund, KP-06-N69/8 (КП-06-Н69/8), “Novel polymer-hybrid materials containing (bio)synthesized metal oxide particles with improved photocatalytic and antimicrobial potential”, for the financial support. The authors acknowledge the technical support from the project PERIMED BG05M2OP001-1.002-0005 /29.03.2018 (2018–2023). Thanks to Liliya Tsvetanova for her technical assistance in the XRF analysis.

Second cheese whey (SCW), a by-product generated after the production of cottage cheese, remains a highly polluted effluent due to its high organic and nutrient load. Despite its environmental impact, the biotreatment of SCW using microalgae/cyanobacteria has been limited, with even fewer studies involving pilot-scale photobioreactors. In this study, unsterilized SCW was treated employing a Leptolyngbya-based culture in two pilot-scale systems: a suspended growth system (SCW-S) and an attached growth system (SCW-A), both operated in 9 L tubular photobioreactors. For the attached system, fishing lines equipped with plastic biofilm carriers served as support material for microbial attachment. Leptolyngbya sp. is known to increase lipid content at C:N ratios of ≈ 45; thus, SCW was studied under these conditions, with an initial d-COD of about 2000 mg L⁻¹. The highest total biomass productivity was observed in SCW-A system, reaching 346.7 mg L⁻¹d⁻¹. Both systems achieved high effectiveness in pollutant removal (d-COD: 94.5-99.9%, TN: 89.0-96.5%, ΝΟ₃⁻-Ν: 87.0-93.3%, PO₄³⁻: 98.8-93.4%), while lipid contents were 16.1 and 15.1% d.w. for SCW-S and SCW-A, respectively. SCW-A proved highly effective, achieving almost complete d-COD (99.9%) and TN (96.5%) removal. Lipid analysis revealed increased saturation of fatty acids in the SCW-A, representing 74.6% of total fatty acids. The attached system was also applied to synthetic chemical medium (CM-A) to evaluate lipid production potential. The CM-A recorded lower biomass productivity (142.8 mg L⁻¹d⁻¹) and lipid content (12.0 % d.w.), suggesting SCW’s indigenous microbiota enhanced growth and lipid production. In conclusion, SCW is an effective feedstock for lipid-rich biomass production with Leptolyngbya, yielding saturated lipids suitable for biofuels.

Manganese carbonate ore/copper and cobalt oxide catalysts were prepared using co-precipitation followed by calcination at 500^oC or hydrothermal synthesis at 160^oC and then thermal treatment. The natural manganese carbonate ore is a suitable support due to its stability and low cost. The phase and chemical composition, structure, morphology, specific surface area, and textural characteristics of the obtained composites were characterized by several methods, such as as powder X-ray analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, electron dispersive spectroscopy, nitrogen adsorption–desorption isotherm, and the BET method. The average crystallite size of 10 nm for Co₃O₄ and 13-23 nm for CuO phases was determined. The prepared composites exhibit mesoporous structure. The highest specific surface area (135m²/g) was established for thermally treated MnCO₃ ore/cobalt oxide in comparison with the other investigated samples. The catalytic activity of synthesized composites was tested in the ecologically important reaction of ozone decomposition. The higher ozone conversion degree was reached using hydrothermally treated MnCO₃ ore/cobalt oxide (87%) and MnCO₃ ore/copper oxide (63%) in comparison with thermally treated catalysts (86% and 54%), respectively.

Acknowledgments: This work has been carried out in the framework of the National Science Program, "Critical and strategic raw materials for a green transition and sustainable development", approved by the Resolution of the Council of Ministers № 508/18.07.2024 and funded by the Ministry of Education and Science (MES) of Bulgaria. The technical support from the project PERIMED BG05M2OP001-1.002-0005 /29.03.2018 (2018–2023) is acknowledged.

Coil coatings are high-performance organic coatings used for many applications, primarily for exterior architecture such as facades, roofing, and rainwater systems. In this process, large metal coils (typically aluminum or steel) pass through a series of fully automated production lines. The applied organic coatings are generally thinner than post-applied paints but consist of multiple layers to prevent corrosion and enhance weather resistance and durability. A coating is composed of resins (polyesters, polyurethanes, etc.), pigments, solvents, and additives combined in various ratios. Normally, these materials are designed to withstand very harsh conditions. However, factors such as UV radiation, high humidity and temperature, prolonged exposure duration, and the chemical composition of both coating and substrate significantly influence their degradation.

Most studies place samples in artificial weathering chambers, which cannot fully replicate the complex interplay of environmental processes. As part of the degradation process, the formation of microplastics is expected. Paint particles are often overlooked or misclassified within the broader category of micro-debris. However, recent findings indicate that paint-derived particles can constitute a significant portion of microplastic pollution.

In this research, samples were collected from the external surface of an existing building made with coil-coated panels and analyzed in the laboratory. The techniques used for microplastic analysis were a stereomicroscope for optical observation, Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy for chemical analysis, and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS) for elemental analysis and surface morphology characterization. This research aims to investigate the causes of microplastic formation, analyze their properties, and better understand their contribution to pollution, leading to the development of reduction strategies. Paint particles were detected in most collected samples, with spectroscopic analysis identifying many as polyester-based materials. A more systematic sampling approach is needed to determine all environmental processes affecting the degradation of existing structures.

The escalating presence of dye pollutants in industrial effluents has rendered the pursuit of environmentally benign and economically sustainable remediation strategies increasingly imperative. Among emerging solutions, the application of biosorbents derived from agro-industrial residues, such as olive pomace, has garnered significant interest due to the low cost and promising efficiency of these residues. This study explores the sorption capabilities of biosorbents and biochars synthesized from olive pomane via water-activation and pyrolysis, respectively, for the removal of dye compounds from aqueous solutions. The materials underwent comprehensive characterization through BET surface area analysis, Raman Spectroscopy, Fourier transform infrared spectroscopy (FTIR), elemental analysis and scanning electron microscopy (SEM). Sorption performance was assessed using two representative dyes—Safranin and Methylene blue—while the kinetics, isotherms and pH influence on the sorption process were thoroughly investigated. Both dyes exhibited satisfactory removal rates, with no significant discrepancies observed in the sorption efficiency between the two, indicating the versatility of the material across different dye classes. The results revealed a markedly improved sorption capacity for the pyrolysed material relative to its water-activated counterpart, a performance attributed to its enhanced porosity and surface area. These findings underscore the potential use of biochar derived from olive pomace as an efficient, low-cost sorbent for dye-laden wastewater. Ultimately, this study highlights the valorization of agri-food by-products as viable tools for wastewater treatment, aligning with broader goals of circular economy advancement and sustainable waste management.

Introduction

Periodontitis is a chronic inflammatory disease triggered by dysbiotic dental biofilms and is a leading cause of adult tooth loss. Conventional treatments (scaling and antibiotics) often leave residual pathogens and biofilms behind. Nanomedicine strategies are thus sought. Gold nanoparticles (AuNPs, ~50–150 nm) are promising carriers: they have excellent bioavailability, can mediate photothermal therapy, and exhibit intrinsic antibacterial/antifungal properties. Functionally, AuNPs can be engineered to target periodontal pathogens while also modulating inflammation and tissue regeneration.

Methods

Through a literature review, we propose to synthesize AuNPs via the green reduction of chloroauric acid using plant extracts (e.g. ginger rhizome or tea polyphenols). These bio-capped AuNPs will then be loaded with periodontal antibiotics (e.g. metronidazole, doxycycline or chlorhexidine) via surface conjugation or embedding. We may also formulate AuNP–antibiotic complexes in biodegradable hydrogels or coatings for sustained, localized release. Downstream, the process will be scaled using bioreactor-based production and continuous flow systems.

Expected Results

The proposed AuNP–antibiotic therapy is expected to yield potent antibacterial activity and enhanced tissue repair. In vitro, we anticipate the strong inhibition of major periodontal pathogens, while in vivo, similar AuNP systems have demonstrated dramatic effects: for instance, 45 nm AuNPs significantly reduced periodontal inflammation and greatly enhanced new attachment, bone and cementum formation. Likewise, an epigallocatechin-gallate–AuNP hydrogel (E-Au@H) in rats eradicated ~87% of dental biofilm and reduced alveolar bone loss by ~38% under NIR irradiation. We expect our antibiotic–AuNP composites to likewise suppress biofilms, modulate macrophage phenotypes, and promote periodontal regeneration.

Conclusion

This poster will present a combination of green nanotechnology with scalable engineering to tackle periodontitis through green nano-synthesis that is suitable for the large-scale production of nanoparticles. The proposed bio-based AuNP platform could provide a sustainable, targeted therapy that combines strong antimicrobial action with immunomodulation and tissue regeneration, addressing unmet needs in periodontal treatment.

Tetracycline (TC), a widely used antibiotic, is frequently detected in wastewater effluents, raising concerns about environmental persistence and antibiotic resistance. In this study, the adsorption potential of copper oxide (CuO), iron disulfide (FeS₂), and zeolite Y (HY) was preliminarily assessed for TC removal from aqueous media. CuO and FeS₂ were synthesized via precipitation and hydrothermal routes, respectively, while ammonium zeolite Y was calcined at 550 ℃ for 3 hours to obtain Zeolite HY. The three adsorbents were characterized using FTIR, XRD and SEM-EDX techniques. The FTIR result showed the functional groups at the fingerprint wavebands; Cu-O stretching vibration was seen at 500 – 600 cm^-1, Fe-S vibrational mode was observed at 430-470 cm^-1 and the Si-O-Si / Al-O-Al asymmetric stretching of the framework of Zeolite HY was seen at 1000-1100 cm^-1. The XRD method displayed the characteristic peaks of the individual components while the SEM images of CuO and FeS₂ showed aggregated irregular-shaped particles and flat sedimented particles, respectively. Elemental compositions were illustrated from SEM-EDX, showing the presence and composition of individual element of CuO and FeS₂. All three adsorbents were tested for adsorption in the dark under varying conditions: adsorbent dosage (0.2–1.2 g/20 mL), pH (3–13), contact time (30–150 min), and initial TC concentrations (20–140 mg/L). CuO achieved a maximum TC removal efficiency of 91.4% at pH 9 with 0.6 g/20 mL dosage after 120 minutes, following pseudo-second-order kinetics. For FeS₂, dosage variation showed an increasing trend in removal, peaking at 81.2 % with 1.2 g/20 mL, but performance declined sharply under acidic and basic conditions, likely due to pH-induced surface instability. The HY zeolite also exhibited high adsorption (89.4 % at 0.6 g/20 mL). These results suggest all as promising adsorbents for TC, with FeS₂ and HY showing potential for integration into composite materials.

The presence of phosphates in wastewater is a growing concern worldwide, which is why there is currently interest in finding alternatives to remove them and avoid problems such as water eutrophication. Another important trend is the development of processes for utilizing agro-industrial waste to add value to production chains. In this sense, this work studied the removal of phosphates from water using an adsorbent composed of sacha inchi cuticle and eggshell in a 1:10 ratio, pyrolyzed at 400°C for 20 min. For this, a filtration system was constructed using 10 cm diameter PVC pipes and employing 155.56 g of the adsorbent, which corresponded to a filtering medium volume of 1.3x10^-3 m³. With these design parameters, a working flow rate of 0.020 m³/h and a filtration velocity of 2.52 m³/m²*h were established, which would correspond to a filter with an average velocity rate. To test the system, 8L of a solution at a concentration of 133 mg/L of PO₄^-3 was prepared. This solution was pumped through the filter using a submersible pump of 25 W, taking samples while recovering 1, 1.5, and 5 L of filtrate, respectively. Subsequently, through spectrophotometric analysis, the removal of phosphates was quantified in duplicate. As a result, a PO₄^-3 removal percentage of 35.58 ± 1.57% was obtained. It is relevant to note that the filtration time required to recover 5 liters of filtrate was slightly more than 12 min. In conclusion, although the removal percentage is lower than that reported by other authors using similar materials as adsorbents, the difference is likely due to the conditions associated with the preparation of the adsorbent. Other conditions could be assessed to improve the removal percentage, contributing to the understanding of these residues and their valorization in the development of sustainable processes.

Anaerobic digestion is an effective and green alternative to treat various types of organic waste and to convert part of the feedstock into biogas that can be further treated to yield biomethane. Slovakia´s biomethane production potential represents up to 10 % of Slovakia´s natural gas consumption and is largely unexploited to date. Batch or continuous-type reactors may be employed, in which organic substrates are transformed into biogas and digestate. Depending on feedstock properties, two technological approaches can be considered, differing in feedstock solids content: wet (below 15%) and dry (above 20%). The biogas produced consists (on a dry basis) largely of methane (~55% vol.), followed by carbon dioxide (~40% vol.), with nitrogen, oxygen, and hydrogen sulphide representing typical minor components and impurities. The aim of this paper is to develop a model of each available technology (continuous, dry batch, wet batch), as well as that of a biogas treatment unit, andto evaluate the energetic, economic, and environmental potential of building a new anaerobic digestion plant in Slovakia, supplied by organic waste collected with a radius of 30 km. Feedstock composition and availability, energy integration, and product usability are evaluated. Multi-criteria decision analysis (MCDA) is applied to the considered plant configurations to identify the most viable and sustainable solution for anaerobic digestion plant application in Slovakia.

Ultrasound-Assisted Extraction (UAE) has emerged as a promising green technique for the efficient recovery of bioactive compounds from medicinal plants, due to its low energy consumption, reduced solvent use, and high extraction efficiency. In this study, UAE was applied to extract phenolic compounds from a medicinal plant species belonging to the Scrophulariaceae family. The influence of five key extraction parameters was investigated: ethanol concentration, extraction temperature, extraction time, solvent-to-solid ratio, and ultrasound power. A single-factor experimental approach was employed, where each parameter was varied individually while the others were kept constant, in order to assess its individual impact on total phenolic content (TPC). The Folin–Ciocalteu method was used to quantify TPC in the resulting extracts. The maximum TPC obtained for each parameter was as follows: 149.920 ± 3.12 µg GAE/mg dry extract at 60 °C, 52.601 ± 4.32 µg GAE/mg dry extract at 50 % ethanol, 119.687 ± 1.09 µg GAE/mg dry extract at 100 min, 110.53 ± 1.14 µg GAE/mg dry extract at 60 mL/g, and 91.209 ± 2.67 µg GAE/mg dry extract at 60 % ultrasound power. These values correspond to the highest TPC observed when each factor was optimized individually under fixed conditions for the others. Among all parameters tested, temperature exhibited the most significant impact on the extraction efficiency of phenolic compounds, while ultrasound power had a slight effect. Overall, this study confirms the potential of UAE as an environmentally friendly technique for the extraction of high-value phenolic compounds and highlights the importance of optimizing process parameters to improve extraction yield.