Plant-based coagulants have gained popularity as a sustainable and cost-effective alternative to chemical coagulants. In this work, a novel plant-based coagulants, produced from seeds of Chelidonium majus L., Dactylis glomerata L., Festuca ampla Hack., Tanacetum vulgare L. and rachis of Vitis vinifera L. were applied in combination with bentonite, aiming at the removal of methylene blue (MB) from aqueous solution. The analysis performed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and Brunauer–Emmett–Teller (BET), showed that these are porous materials with capacity to adsorb the contaminant from the solution.

The coagulation-flocculation-decantation (CFD) process was optimized, by variation of the pH (3.0 – 7.0, coagulant dosage (0.1 – 2.0 g/L), agitation conditions and bentonite dosage (0.1 – 2.0 g/L), with a sedimentation time of 12 h. Under the best operational conditions, it was observed a MB removal of 90.9, 91.9, 91.4, 86.9 and 88.9%, respectively. In conclusion, plant-based coagulants mixed with bentonite are a biologic, sustainable and cheap alternative for MB removal.

The production of high-purity hydrogen is very important for the efficient operation of fuel cells based on proton-exchange membranes. One of the best solutions to this problem is the use of membrane catalysis processes. The study of methanol steam reforming (MSR) over Pt-Rh/TiO₂-In₂O₃ catalyst was carried out in traditional and membrane reactors using Pd-Cu foil treated by various methods. This catalyst showed the highest catalytic activity in a conventional reactor. The methanol steam reforming occurs at the interface between the Pt-Rh alloy and the oxide support. The oxygen vacancies formation in the oxide structure leads to the water sorption increase and the diffusion rate of oxygen-containing groups on the surface increase. There is the data in the literature about the catalytic activity of indium oxide. Therefore, it can be assumed that the use of this support can promote the catalytic activity of the Pt-Rh alloy. The main products of MSR over Pt-Rh/TiO₂-In₂O₃ catalyst were hydrogen and carbon dioxide. The use of surface-treated membranes in catalysis should increase the efficiency of processes occurring at relatively low temperatures and made it possible to produce high-purity hydrogen. The best results (hydrogen yield) are achieved in a membrane reactor with the use Pt-Rh/TiO₂-In₂O₃ catalyst and Pd-Cu membrane after hard rolling. At the same time, the hydrogen recovery degree on the permeate zone on this membrane reached 60%. This is more compared to the foil treated after ultrasonic cleaning and double-sided photonic treatment (20%).

Solid mixing is an essential unit operation in various industries including food, pharmaceutical, and cosmetics. Thus, a better understanding of the underlying mechanisms affecting the performance of solid mixers can help industries determine the best design and operating conditions for the mixing processes. Both experimental and numerical techniques have been used to analyze the operations of the solid particle blenders. The limitations associated with experimental techniques such as disturbance of the granular flow path, cost, and cumbersome implementation made the Discrete Element Method (DEM) a complementary tool to obtain comprehensive particle-level information about mixing systems. However, the DEM technique suffers from high computational time and requires enormous computing power. To address these challenges, some DEM studies have used spherical particles models even though the experimental and numerical studies have demonstrated the pronounced effect of the particle shape on the mixing quality. However, the use of graphics processing units (GPUs) has enabled us to run DEM simulations of mixing systems containing non-spherical particles with less computation time. In this study, mixing kinetics and flow patterns of non-spherical particles in a horizontal double paddle blender are investigated using both experiments and DEM. Firstly, a set of experimental data is obtained using image analysis from a rotary drum containing cubical and cylindrical particles. Additionally, the EDEM v2021 commercial software is utilized as the GPU-based DEM solver. Then, the DEM model was calibrated using the experimental data. Using the calibrated DEM model, the effects of operating parameters such as vessel fill level, particle loading arrangement, and impeller rotational speed on the mixing performance are examined. The relative standard deviation (RSD) is calculated to assess the mixing performance. Analysis of the DEM results enables us to find the optimum design parameters and processing conditions for the mixing of non-spherical particles in a double paddle blender.

A new approach for the synthesis of highly active nanostructured catalysts on the surface of Pd-23%Ag films is proposed in order to intensify low-temperature (up to 100°C) hydrogen transport through hydrogen-selective palladium-containing membranes. The deposition of such catalyst significantly accelerates the surface stages of hydrogen transport (dissociative adsorption and recombinative desorption), that results in the increase of the hydrogen flux at low temperatures. It has been found that the formation of such functional coating is possible only if the current density during electrolytic deposition is lower than in classical methods and if a surfactant is added to the growth solution to facilitate the formation of a defined particle morphology. The developed nanostructured catalyst demonstrates a significant increase in catalytic activity in the reaction of alkaline oxidation of methanol, in comparison with palladium black. This is most likely due to an increase in the number of active sites in the material, compared with classical synthesis methods, which enhances the activity of the material with respect to reactions involving hydrogen. Evaluation of resistance to CO poisoning demonstrated the high efficiency of nanocatalysts. A chronoamperometry confirms the long-term stability and activity of the presented catalyst as well as the possibility of its practical use in catalytic and membrane applications.

Li₄Ti₅O₁₂ is considered as a promising anode material for lithium-ion batteries, primarily due to low degradation during cycling and high safety. However, its electronic and ionic conductivities are relatively low that limits its practical application. The design of composites with conductive materials, e.g., with carbon, is one of the approaches to improve the electrochemical properties of materials. In this work, the composite nanomaterials based on Li₄Ti₅O₁₂ and carbon nanotubes (CNTs) or carbon nanoflakes, including N-doped ones were prepared, in the aim to compare the effect of various carbon nanomaterials and synthesis method on the electrochemical performance of Li₄Ti₅O₁₂/C composites.

The composite nanomaterials based on hydrothermally or sol-gel synthesized Li₄Ti₅O₁₂ and CNTs or carbon nanoflakes, including N-doped ones were prepared and investigated by XRD, TEM, SEM, Raman spectroscopy, low-temperature nitrogen adsorption, dc-measurements, charge-discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. Carbon introduction provides the formation of a highly conductive 3D network resulting in increase in the electronic conductivity, lithium diffusion and thus improvement of high-rate performance.

At high charge/discharge rates, the discharge capacity of the prepared anodes significantly exceeds that of the pristine Li₄Ti₅O₁₂. At 37C rate, the reversible discharge capacities of lithium titanate, and its composites with CNTs and N-doped CNTs are of 60, 97, and 90 mAh/g, respectively. They exhibit a remarkable long-term cycling stability.

The present production and global consumption of plastics (especially for packaging) is continuously increasing, leading to an inefficient waste management system. One of the major environmental risks is the slow rate of its degradation or even the non-biodegradability of some organic compounds in real life systems. Therefore, green additives and adequate processing of the packaging materials are needed to intensify the plastic biodegradation under natural conditions. In this work, commercial grade low-density polyethylene (LDPE) with 1% rosemary (Rosmarinus officinalis) extract was used for the preparation of composite films, without further treatment or purification. The biodegradability studies were carried out by incubating the unmodified and modified composites with Aspergillus Niger. The thermal runs were performed on a SETARAM microDSC 7 evo differential scanning calorimeter within the 50–120^oC temperature range, at heating rates of 0.3, 0.4, 0.5, 0.6 and 1 ^oC min^-1, in nitrogen atmosphere with a flow rate of 50 mL min^-1. The results show that the slight increase in the crystallinity degree after microbial attack can be caused by consumption of the amorphous part of polymer by microorganisms. Peak melting temperatures are practically unaltered within experimental errors. Based on microcalorimetric results it can be concluded that rosemary extract can be used for increasing the biodegradability of polyethylene films via reducing of its crystallinity degree.

The generation of agro-industrial byproducts is increasing at a fast rate all over the world. In Mediterranean regions, the production of wine achieved a value of 2.92x10¹⁰ L in 2018 and the production of olive achieved a value of 3.2 million ton in 2015/2016. These two agro-industries generate high volumes of wastewater, with a high content alcohols, organic acids, sugars and phenolic compounds, capable of great environmental impact with notable effects such as pollution of water, degradation of soil, odors and air emissions and low biodegradability.

In this work, it was collected and reviewed recent findings aiming the feasibility of coagulation-flocculation-decantation (CFD) and advanced oxidation processes (AOPs) for the treatment of agro-industrial wastewaters. The application of plant-based coagulants and oenological coagulants revealed to be effective in the removal of turbidity and total polyphenols from the wastewater. The literature review showed that the application of AOPs was effective for the removal of organic matter from the wastewater. It was also observed by several authors that hydroxyl radical (HR)-AOPs, sulfate radical (SR)-AOPs and ozone-AOPs were more effective with the application of ultra-violet (UV) radiation, due to the increase of hydroxyl and sulfate radicals generation. Finally, based in literature review, the combination of CFD with AOPs achieved higher removal results, considering that the pre-treatment with CFD process reduces the turbidity and suspended solids from the agro-industrial wastewaters, allowing the radiation to penetrate more easily. In conclusion, the application of CFD process as a pre-treatment followed by AOPs are an efficient process for agro-industrial wastewater treatment.

Municipal wastewater treatment produces significant quantities of sludge, that need appropriate treatment so it can be used for another purpose without constituting a threat to the environment, contributing to a sustainable circular economy.

In this work, the efficiency of ultrasound, Fenton reagent and ultrasound-Fenton (US-Fenton) processes were evaluated separately, for the treatment of municipal activated sludge. Additionally, the effects of operational parameters such as pH, hydrogen peroxide and ferrous iron concentrations, and cavitation time were studied. During the experiments, the COD reduction and the volatile solids vs total solids (VS/TS) ratio were followed, trying to reach the optimal experimental conditions.

According to the results, pH = 4.0, hydrogen peroxide concentration of 30 mM, ferrous iron concentration of 2.0 mM and a reaction time of 60 min (cavitation: 3 s ON and 5 s OFF), were selected as optimal conditions. Analyzing the results, ultrasound and Fenton processes allowed to reach 17.3 and 25.9% of COD removal, respectively, while the combined US-Fenton was more efficient with a 94.8% COD reduction. Regarding the VS/TS ratio, the process that showed better results was US-Fenton once again, reducing the original value of 0.59 to 0.16. The ultrasound and Fenton processes showed a lower VS/TS ratio reduction to 0.26 and 0.22, respectively.

In conclusion, the combination of ultrasound-Fenton (US-Fenton) achieved high COD removal and a significant VS/TS ratio reduction of the municipal activated sludge, showing better efficiencies than both processes separately.

Lithium metal batteries are a promising replacement for lithium-ion batteries due to their ability to achieve high energy densities. However, the unsafe operation of the lithium battery due to the formation and sprouting of dendrites through the separator limits their commercial application. The most important problem limiting the large-scale application of batteries with a lithium anode is the growth of dendrites through a commercial separator. According to space charge theory, low lithium cation transfer numbers lead to dendrite formation, so using single-ion conducting electrolytes is one way to prevent dendrite formation. Nafion membrane was proposed as such an electrolyte, but it was shown that the solvation of these membranes with standard organic carbonates does not provide sufficient ionic conductivity. It was shown that the conductivity of Nafion membrane solvated by dimethylacetamide (DMAc) are significantly higher than those for standard carbonate solvents. However, some works report low chemical stability of DMAc in contact with alkali metals, and the use of mixtures of DMAc with ethylene carbonate increases stability by creating a protective film that prevents the interaction of DMAc with the metal. We obtained a gel-polymer electrolyte based on a Nafion cation-exchange membrane solvated with a ternary mixture of ethylene carbonate - dimethyl carbonate - N,N-dimethylacetamide, which has an ionic conductivity of 1.8 mS/cm at 25°C and an electrochemical stability window of 4.1 V. The symmetrical Li|Li cell was shown to cycle stably at a current density of 0.1 mA/cm2 for >350 h.

Pharmaceutical industries widely use Escherichia coli cell strain to synthesize various target products. The main goal is to reach the highest possible product yield. However, throughout the cell growth stage, the formation of by-products is inevitable. Metabolic compounds such as acetates cause inhibition, particularly in later bioprocess stages. The acetate accumulation model is necessary for planning bioprocesses to maximize cell biomass growth. This work depended on a black-box model. The decision tree method was in possession to replicate the approach. Specific biomass growth [1] at induction, broth weight, oxygen uptake rate [2], consumed substrate weight served for model training. Broth and consumed substrate weight had additional aging-related information [3] incorporated as separate inputs to introduce the cumulative regularization. Growth-limiting and non-growth-limiting dose feeding, bioprocess data used for black-box model training and validation. 80% of data served for model training. 20% functioned for model validation and 20% for both training validation. Mean absolute error (MAE) and residual sum of squares (RSS) were the criteria for validation. With used inputs and decision tree parameters, the best MAE was lower than 0.2, and the lowest RSS was lower than 2.

Funding: This project received funding from the European Regional Development Fund (project no. 01.2.2-LMT-K-718-03-0039) under a grant agreement with the Research Council of Lithuania (LMTLT).

References

1. Urniezius and A. Survyla, “Identification of Functional Bioprocess Model for Recombinant E. Coli Cultivation Process,” Entropy, vol. 21, no. 12, p. 1221, Dec. 2019, doi: 10.3390/e21121221.
2. Survyla, D. Levisauskas, R. Urniezius, and R. Simutis, “An oxygen-uptake-rate-based estimator of the specific growth rate in Escherichia coli BL21 strains cultivation processes,” Computational and Structural Biotechnology Journal, vol. 19, pp. 5856–5863, 2021, DOI: 10.1016/j.csbj.2021.10.015.
3. Urniezius, B. Kemesis, and R. Simutis, “Bridging Offline Functional Model Carrying Aging-Specific Growth Rate Information and Recombinant Protein Expression: Entropic Extension of Akaike Information Criterion,” Entropy, vol. 23, no. 8, p. 1057, Aug. 2021, doi: 10.3390/e23081057.