Sulfonated Poly(Ether Ether Ketone)/Praseodymium Doped Zinc Ferrite Composites as Promising Polyelectrolyte Membranes for Fuel Cells Laurentiu Baltag, Petrisor Samoila, Corneliu Cojocaru, Mihai Asandulesa, Mariana Cristea, et al. Polymers, 2025 Sulfonated poly(ether ether ketone) (SPEEK) is one of the most studied ionic polymers for polymer electrolyte membranes (PEMs) in fuel cells (PEMFCs). To improve its proton conductivity, novel SPEEK/praseodymium-doped zinc spinel ferrite composite membranes of 130–170 μm thickness were prepared via ultrasound-assisted dispersion of various proportions of synthesized doped ferrite nanoparticles into the polymer solution, followed by a simple solution-casting method. The morphology (as observed by SEM and confirmed by DMA) and the conducted physical and chemical tests typical for PEMs, such as water uptake (32–44% at 80 °C), ionic exchange capacity (1.67–1.80 mEq/g), chemical (around 1% loss in Fenton reagent after 24 h), thermal stability (up to 190 °C) and tensile strength (39–50 MPa), were proven to depend on the content of inorganic filler in the composite (up to 5%). The proton conductivity of composite membranes (0.21–2.82 × 10−2 S/cm at 80 °C) was assessed by broadband dielectric spectroscopy. The membrane with a content of 0.25 wt.% ZnFe1.96Pr0.04O4 showed the best proton conductivity (3.41 × 10−2 S/cm at 60 °C), as compared to 1.60 × 10−2 S/cm for Nafion117 measured under the same conditions, demonstrating its suitability as a PEM for fuel cell applications.
Assessment of Hedera helix response in polluted environment through cross-advanced investigation techniques Gabriela Lisa, Igor Cretescu, Catalin Tanase, Constantin Mardari, Nita Tudorachi, et al. Journal of Thermal Analysis and Calorimetry, 2025 Establishing plant–pollutant interaction and pollutant uptake mechanism for botanical biofilters treating contaminated air is one of the challenges of moving forward implementation of such biosystems in practice. Cross-investigation of Hedera helix leaf changes during toluene exposure has been undertaken in the actual study for providing more insights into this process, by using samples collected before and after experiment from a biofilter continuously operated with toluene-rich air. Results of FTIR, LP, SEM, EDX and TG/MS/FTIR for the analyzed leaf reveal that toluene uptake occurs via adsorption as a dominant mechanism, while lignin might be affected by toluene under certain circumstances. Overall, a stimulating effect of toluene on plant metabolism was observed, supporting the plant suitability to be involved in biofilters for treating traces of toluene in ambient air. These in-depth screening of plant-based process aspects might not be easily pointed out by other technics either because they are dispersed in different thematic areas or too sophisticated or not accessible. Moreover, the integrated TG/MS/FTIR technique has not been used so far to assess ivy leaves; thus, the actual study can serve as a model for other studies in such related topics.
Synthesis and Characterization of Carboxymethylcellulose-Functionalized Magnetite Nanoparticles as Contrast Agents for THz Spectroscopy with Applications in Oncology Oliver Daniel Schreiner, Petrisor Samoila, Thomas Gabriel Schreiner, Diana Socotar, Romeo Cristian Ciobanu Crystals, 2024 This paper describes a process to obtain magnetite functionalized with carboxymethylcellulose via coprecipitation by means of a preliminary stabilization of magnetite in citric acid. The magnetite assemblies successfully passed in vitro and in vivo tests of bio-compatibility. The measured values for the dielectric loss factor are remarkably high, a prerequisite for the assemblies’ potential use as contrast agents. Broadband THz spectroscopy analysis was performed to identify the most relevant frequency bands (here, 3.2–4 THz) where the signal difference between normal cells and cancer cells is relevant for the particles’ potential use as contrast agents for THz imaging, with applications in oncology.
Polyethylene Terephthalate (PET) Recycled by Catalytic Glycolysis: A Bridge toward Circular Economy Principles Andra-Cristina Enache, Ionela Grecu, Petrisor Samoila Materials, 2024 Plastic pollution has escalated into a critical global issue, with production soaring from 2 million metric tons in 1950 to 400.3 million metric tons in 2022. The packaging industry alone accounts for nearly 44% of this production, predominantly utilizing polyethylene terephthalate (PET). Alarmingly, over 90% of the approximately 1 million PET bottles sold every minute end up in landfills or oceans, where they can persist for centuries. This highlights the urgent need for sustainable management and recycling solutions to mitigate the environmental impact of PET waste. To better understand PET’s behavior and promote its management within a circular economy, we examined its chemical and physical properties, current strategies in the circular economy, and the most effective recycling methods available today. Advancing PET management within a circular economy framework by closing industrial loops has demonstrated benefits such as reduced landfill waste, minimized energy consumption, and conserved raw resources. To this end, we identified and examined various strategies based on R-imperatives (ranging from 3R to 10R), focusing on the latest approaches aimed at significantly reducing PET waste by 2040. Additionally, a comparison of PET recycling methods (including primary, secondary, tertiary, and quaternary recycling, along with the concepts of “zero-order” and biological recycling techniques) was envisaged. Particular attention was paid to the heterogeneous catalytic glycolysis, which stands out for its rapid reaction time (20–60 min), high monomer yields (>90%), ease of catalyst recovery and reuse, lower costs, and enhanced durability. Accordingly, the use of highly efficient oxide-based catalysts for PET glycolytic degradation is underscored as a promising solution for large-scale industrial applications.
Dynamic Adsorption of a Cationic Dye onto Wool Fibers as Column-Filling Media: Response Surface Optimization and Fixed-Bed Adsorption Modeling Bogdan-Constantin Condurache, Corneliu Cojocaru, Alexandra Bargan, Petrisor Samoila, Valeria Harabagiu Materials, 2024 This study reports a simple and low-cost method for water purification using recyclable natural fibers (coarse wool fibers) as column-filling media for adsorption in the dynamic mode. As an instance of a dissolved organic pollutant, a cationic dye (basic blue 9, BB9) was assayed. According to the Langmuir isotherm (recorded at 300 K), the calculated maximum adsorption capacity of the fibrous material was found to be 24.86 mg/g for the retention of BB9. Response surface methodology (RSM) was employed for the design of experiments and the model-based optimization of the adsorption process performed in the dynamic regime (fixed-bed column). The optimal conditions provided by RSM indicated an adsorbent column height of H = 13.5 cm and a feed flow rate of Fv = 3 mL/min; these operating parameters ensured a color removal efficiency of 92.56% after 240 min of contact time. The recorded breakthrough curve under the optimal conditions was further interpolated using five quantitative mathematical models (Adams–Bohart, Thomas, Yoon–Nelson, Yan, and Clark) to assess the dynamic behaviors in the fixed-bed column. The best goodness-of-fit was achieved for the Thomas and Yoon–Nelson models. Thus, the coarse wool fibers used in a fixed bed demonstrated a relevant efficiency in the removal of cationic organic pollutants from contaminated water.
A model microalga for addressing air treatment in spacecrafts Gabriela Soreanu, Igor Cretescu, Mariana Diaconu, Maria Ignat, Valeria Harabagiu, et al. From Biofiltration to Promising Options in Gaseous Fluxes Biotreatment Recent Developments New Trends Advances and Opportunities, 2020
Chitin and chitosan for water purification Petrisor Samoila, Andra Cristina Humelnicu, Maria Ignat, Corneliu Cojocaru, Valeria Harabagiu Chitin and Chitosan Properties and Applications, 2019