This paper investigated the kinetics involved in the adsorption of methylene blue (MB) on activated carbon. Tests of the adsorbent (granulometric composition and FT-IR analyses) showed that it contains a wide range of particle sizes (5–250 μm) and that the most frequent vibrations are caused by N=C=N stretching, C=C=C stretching, metal–oxygen vibrations (e.g., Fe-O), and heteroatomic vibrations (C-Cl or C-Br). Increasing the dose of adsorbent and decreasing the initial concentration of methylene blue increases the efficiency of adsorption, while the most intensive adsorption takes up to 10 min. The adsorption process follows pseudo-second-order kinetics, which indicates that adsorption occurs due to chemical interactions between the adsorbate and adsorbent. The results indicate that the use of activated carbon achieves a high level of MB removal, especially under optimized conditions.

In this work, the influence of process parameters (temperature: 25 - 65 °C, ethanol content in the extraction solvent: 30 - 90 vol.%, and solid-to-solvent ratio: 1:15 - 1:45 w/v) on the process of ultrasound-assisted extraction (UAE) of (poly)phenols from blueberry leaves ( Vaccinium myrtillus ) was investigated. Statistical analysis was performed using the MINITAB 21 software, with the application of three-level full factorial designs. The Responses in the study are the content of total (poly)phenols, flavonoids and anthocyanins in the obtained extracts. The extraction of blueberry leaf was significantly (p < 0.05) impacted by process variables. The R ² , Adjusted R ² , and Predicted R ² values in the study are high, showing a significant relationship between the independent variables and the Response. The optimal temperature for all three Responses is 65 °C, the optimal solid-to-solvent ratio for total (poly)phenols and anthocyanins is 1:45 w/v and for flavonoids is 28.03 w/v, while the optimal ethanol content in the solvent for total (poly)phenols, flavonoids and anthocyanins is 51.21 vol.%, 50.61 vol.% and 83.33 vol.%, respectively.

The present paper aims to discover the optimal conditions for ultrasound-assisted extraction (UAE) of (poly)phenolic chemicals from blueberry (Vaccinium myrtillus) leaves. UAE was performed under the following process conditions: temperature: 25?65?C, ethanol concentration in the extraction solvent: 30?90 vol.%, and solid-to-solvent ratio: 1:15?1:45 w/v. Statistical analysis was performed using Design-Expert software, using the Box-Behnken design. The study''s responses were the content of total (poly)phenols, flavonoids, and anthocyanins in the derived extracts. The results indicated that the corresponding response surface models were highly statistically significant (p < 0.0001) and sufficient to describe and predict the content of total (poly)phenols, the content of flavonoids, and the content of anthocyanins with R2 of 0.965, 0.980 and 0.972, respectively. The optimal conditions for the extraction are for total (poly)phenols 48.4 ?C, 51.3 vol.% ethanol, and 1:43.8 w/v solid-to-solvent ratio; flavonoids 58.5?C, 48.0 vol.% ethanol, and 1:29.8 w/v ratio; and anthocyanins 64.2?C, 73.5 vol.% ethanol, and 1:44.7 w/v ratio. The use of UAE enhances extraction yields by increasing the release of bioactive compounds, while the application of the Box-Behnken design allows for precise determination of optimal extraction parameters, thereby achieving maximum yields and efficiency

Aluminium samples were chemically prepared by following operations: degreasing, etching I, etching II, and brightening), prior to anodizing in sulfuric acid. Aluminium surface area was 0.2 dm2. The composition of used aluminium samples was determined by the energy dispersive X-ray spectroscopy. Chemically prepared aluminium samples were electrochemically anodized for 45 minutes in a solution of 190 gdm-3 H2SO4 at room temperature, at a current density of 1.7 Adm-2. In the anodizing process, the aluminium sample served as the anode, with lead cathodes. After anodizing, the aluminium samples underwent a colouring process in five pairs of solutions (systems), where each system consisted of two solutions of inorganic salts RxA + RxB (x = 1-5, numbers of solutions). Colouring of the anodized aluminium was carried out at room temperature by immersing the samples in each solution for 7 minutes (e.g., R1A + R1B, τ = 7 min + 7 min). Each used colouring system provides a different colour: green-yellow, brown, light-grey, blue, and orange-gold. After colouring, the samples were treated in a special solution to improve corrosion resistance and silication, resulting in a change in the obtained colour shade. All obtained colours were stable with very nice appearance, allowing such coloured aluminium to be used for decorative purposes. The corrosion resistance of the coloured anodized aluminium samples was investigated by determining the corrosion potential, corrosion current and polarization resistance using potentiodynamic polarization method, as well as by electrochemical impedance spectroscopy. A common feature of all tested samples is a significant improvement in the corrosion resistance of the anodized aluminium after colouring and subsequent treatment in the corrosion resistance improvement solution, particularly after the additional silane treatment.

This paper shows the preliminary results of an investigation into the possibility of using red mud slag (RMS) for phosphate sorption from aqueous solutions. The red mud slag was obtained from red mud treatment, specifically from carbothermal reduction at high temperatures. This process resulted in forming a metallic phase (iron) and slag enriched with other elements. The preliminary analysis of slag is performed to investigate its potential for use as a phosphate sorbent in wastewater treatment. The slag is divided into three categories. Two of them are obtained by sieving an original slag sample in the fine fraction and the coarse fraction (the slag residual after sieving). The third sample is the raw slag. After an experiment that included 24 h shaking of slag and phosphate solution, the results show potential for using red mud slag in phosphate sorption. It is an initial experiment that will be a starting point for further investigation of the sorption characteristics of red mud slag.

This study investigates the potential of Taraxacum officinale (TO) root extract as an environmentally friendly corrosion inhibitor for two types of steel, TH-550 and TS-275, in an acidic environment. The corrosion inhibition was assessed by monitoring the weight loss of steel samples over a 72-hour immersion period in four different solutions: blank 4% HCl solution and 4% HCl solutions containing 0.5, 1.0, and 1.5 g/L of TO root extract. The inhibitor efficiency, calculated from weight loss data, ranged from 70% to 89%. Surface analysis of the steel samples, conducted after 24 hours of immersion, revealed the formation of a uniform protective film on the steel exposed to the inhibited solutions, while samples in the blank acidic solution showed significant corrosion. Fourier-transform infrared spectroscopy analysis identified key metal-complexing functional groups in the TO root extract, including aromatic C—H, C—O, C=O, and O—H, which are likely responsible for the interaction with the steel surface. Potentiodynamic polarization measurements indicated that the TO root extract acts as an anodic corrosion inhibitor, with the ability to cover up to 88% of the steel surface. Electrochemical impedance spectroscopy, in combination with polarization and weight loss results, demonstrated that the inhibitor efficiency of the TO root extract increases with concentration.