The main goal of wastewater treatment is to significantly reduce organic compounds, micronutrients (nitrogen and phosphorus) and heavy metals and other contaminants (pathogens, pharmaceuticals and industrial chemicals). In this work, the efficiency of removing different contaminants (COD, NO₃⁻, NO₂⁻, NH₄⁺, PO₄³⁻, SO₄²⁻, Pb²⁺, Cd²⁺) from synthetic wastewater was tested using five different yeast strains: Kluyveromyces marxianus CMGBP16 (P1), Saccharomyces cerevisiae S228C (P2), Saccharomyces cerevisiae CM6B70 (P3), Saccharomyces cerevisiae CMGB234 (P4) and Pichia anomala CMGB88 (P5). The results showed a removal efficiency of up to 70% of COD, 97% of nitrate, 80% of nitrite, 93% of phosphate and 70% of sulfate ions for synthetic wastewater contaminated with Pb²⁺ (43 mg/L) and Cd²⁺ ions (39 mg/L). In contrast, the results showed an increase in ammonium ions, especially in the presence of Pb²⁺ ions. The yeast strains showed a high capacity to reduce Pb²⁺ (up to 96%) and Cd²⁺ (up to 40%) ions compared to the initial concentrations. In presence of a crude biosurfactant, the removal efficiency increased up to 99% for Pb²⁺ and 56% for Cd²⁺ simultaneously with an increase in yeast biomass of up to 11 times. The results, which were obtained in the absence of aeration and in neutral pH conditions, proved a high potential for practical applications in the biotreatment of the wastewater and the recovery of Pb and Cd ions, with a high benefit–cost ratio.

This study offers a comprehensive examination, both theoretically and experimentally, of the potential of methanol (M) as a sustainable aviation fuel (SAF) assessed in combination with kerosene (Ke—Jet-A aviation fuel + 5% Aeroshell oil). Different blends of methanol and kerosene (10%, 20%, and 30% vol. of (M) was added to Ke) were tested in an aviation micro turbo-engine under various operating regimes, such as idle, cruise, and maximum. Key engine parameters, including combustion temperature, fuel consumption, and thrust, were closely monitored during these trials. Essential performance indicators such as combustion efficiency, thermal efficiency, and specific consumption for all fuel blends under maximum operating conditions are also presented. Physical and chemical characteristics, such as viscosity, density, calorific value and flash point, were determined for each blend. Moreover, elemental analysis and FTIR spectroscopy were utilized to evaluate the chemical composition of the fuels. This study further investigated the air requirements for stoichiometric combustion and computed the resulting CO₂ and H₂O emissions. Experimental tests were conducted on the Jet Cat P80^® micro turbo-engine, covering assessments of starting procedures, acceleration, deceleration, and pollutant emissions (CO and SO₂) during various engine operating conditions. The results suggest that the examined fuel blends demonstrate stable engine performance at concentrations of 10% and 20% methanol. However, observations indicate that with an increase in methanol concentration, particularly at 30%, the stability of the engine at idle and, notably, at maximum speed decreases significantly. Specifically, at a 30% methanol concentration, the engine no longer operates stably, exhibiting significant rpm fluctuations, leading to the decision not to explore higher concentrations.

The use of hydrogen as fuel presents many safety challenges due to its flammability and explosive nature, combined with its lack of color, taste, and odor. The purpose of this paper is to present an electrochemical sensor that can achieve rapid and accurate detection of hydrogen leakage. This paper presents both the component elements of the sensor, like sensing material, sensing element, and signal conditioning, as well as the electronic protection and signaling module of the critical concentrations of H₂. The sensing material consists of a catalyst type Vulcan XC72 40% Pt, from FuelCellStore, (Bryan, TX, USA). The sensing element is based on a membrane electrode assembly (MEA) system that includes a cathode electrode, an ion-conducting membrane type Nafion 117, from FuelCellStore, (Bryan, TX, USA). and an anode electrode mounted in a coin cell type CR2016, from Xiamen Tob New Energy Technology Co., Ltd, (Xiamen City, Fujian Province, China). The electronic block for electrical signal conditioning, which is delivered by the sensing element, uses an INA111, from Burr-Brown by Texas Instruments Corporation, (Dallas, TX, USA). instrumentation operational amplifier. The main characteristics of the electrochemical sensor for hydrogen leakage detection are operation at room temperature so it does not require a heater, maximum amperometric response time of 1 s, fast recovery time of maximum 1 s, and extended range of hydrogen concentrations detection in a range of up to 20%.

The presence of nutrients in aquaculture water bodies causes serious problems for aquatic ecosystems, requiring the development of technical solutions to reduce their amounts. This work identifies some bacterial strains that are able to reduce nutrient quantities and studies the effect of antibiotics on bacterial growth, on the ability to form biofilms on different solid supports, and on the ability to reduce nutrients in aquaculture wastewater. Bacterial biofilm adhesion on different substrates depends on the surface properties of the substrate, on the bacterial types that form the biofilm, but also on biofilm–substrate interactions. The obtained results revealed the high capacity of biofilm-forming bacterial strains of Pseudomonas aeruginosa and Chromobacterium violaceum to eliminate up to 87% of nitrate and nitrite ions and up to 62% of phosphate ions in the presence of concentrations of 0.1–0.4 µg/mL of oxytetracycline antibiotic from aquaculture wastewater.

Experimental assessment of the hydrogen (H₂)-adsorption capacities of metal-doped carbon nanostructured materials were investigated in this study. Given their intrinsic characteristics, nanostructured carbonic materials show great potential for different applications that require H₂, one such being their use as hydrogen carriers in the automotive sector. The current paper considers two types of carbonic substrates (carbon nanotubes and polyaniline) functionalized and doped with platinic metals: Pt, Ru and Ir. The H₂-adsorption capacities of the materials were assessed at 293 K and at relatively low pressures (10, 20 and 30 bar). Thus, nanostructured polyaniline (p-C₆H₅NH₂) and multi-walled carbon nanotubes (MW-CNTs) were subject to noble-metal doping in order to assess their physical H₂-adsorption capacities. The two types of substrates have different structures and characteristics, one being a “synthetic metal” and the other an amorphous carbon substrate. The metals used for doping were Platinum (Pt), Iridium (Ir) and Ruthenium (Ru), and the doping procedure consisted of chemical reaction between the metals’ salts and the carbonic substrate after the latter’s physical activation. Physical H₂-adsorption capacity was determined with equipment designed to measure porous materials’ adsorption capacities at pressures ranging from 1 to 200 bar. The obtained results showed an increase inH₂-adsorption capacity of 293% from 10 to 30 bar for Ru, 270% for Ir and 256% for Pt doping in the case of the MW-CNTs, and 296% for Ru, 282% for Ir and 251% for Pt from 10 to 30 bar in the case of p-C₆H₅NH₂. As the main conclusion, even though Pt is known to be the main metal used in reactions involving H₂, Ru and Ir showed better potential for this application, namely, as hydrogen-carrier materials for use in the automotive sector.