Peroxide Initiator Research Articles

Metformin suppresses metabolic dysfunction-associated fatty liver disease by ferroptosis and apoptosis via activation of oxidative stress

Metformin is known for its antioxidant properties and ability to ameliorate metabolic dysfunction-associated fatty liver disease (MAFLD) and is the focus of this study. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is linked to MAFLD risk. This study investigated the effects of metformin on ferroptosis in free fatty acid (FFA)-treated Huh7 hepatoma cells and its association with MAFLD risk. Using Western blot, immunofluorescence, and ELISA, this study revealed that FFA treatment led to increased intracellular fat and iron accumulation, heightened Lp-PLA2 expression, reduced levels of the cysteine transporter SLC7A11 and glutathione peroxidase 4 (GPX4), altered glutathione (GSH)/oxidized glutathione (GSSG) ratios, generation of reactive oxygen species (ROS), and initiation of lipid peroxidation, which ultimately resulted in cell ferroptosis. Importantly, metformin reversed FFA-induced iron accumulation, and this effect was attenuated by ferrostatin-1 but enhanced by erastin, RSL3, and si-GPX4. Additionally, metformin activated antioxidant and antiapoptotic mechanisms, which reduced lipid peroxidation and suppressed Lp-PLA2 expression in FFA-treated Huh7 cells. In conclusion, our findings indicate that metformin may protect against MAFLD by inhibiting iron accumulation and Lp-PLA2 expression through the ROS, ferroptosis, and apoptosis signaling pathways. This study highlights potential therapeutic strategies for managing MAFLD-related risks and emphasizes the diverse roles of metformin in maintaining hepatocyte balance.

Self-healing and degradable functionalization of EVA hot-melt adhesives based on disulfide bonds and polymer free radical copolymerization

This study aims to provide a new approach for the industrialization of self-healing adhesive or membrane materials. EVA hot melt adhesive has a market share of over 50 %, and it needs to be cured during use. It is a thermosetting resin that is difficult to recycle and reuse. In response to the defects mentioned above, we developed a self-healing and degradable EVA-based hot-melt adhesives (EDS) based on disulfide bonds and polymer free radical copolymerization. Specifically, we used divinyl disulfide as a crosslinking agent. Under the action of a peroxide initiator, disulfide and EVA formed a cross-linked network through free radical copolymerization. In the study, we characterized the Functionality and comprehensive performance of EDS using various testing methods such as FT-IR, DSC, and SEM. The research results indicate that EDS achieves self-healing and degradation by utilizing the rearrangement reaction of disulfide bonds under ultraviolet light and its reducibility under strong alkaline conditions. While maintaining the same electrical insulation performance, the barrier performance, thermal conductivity, aging resistance, and mechanical properties of EDS have all been improved. Meanwhile, we discussed the self-healing mechanism, curing kinetics, degradation mechanism, and aging mechanism of EDS.

Bubble-Free Frontal Polymerization of Acrylates via Redox-Initiated Free Radical Polymerization.

Thermal frontal polymerization (FP) of acrylate monomers mixed with conventional peroxide initiators leads to significant bubble formation at the polymerizing front, limiting their practical applications. Redox initiators present a promising alternative to peroxide initiators, as they prevent the formation of gaseous byproducts during initiator decomposition and lower the front temperature, thereby enabling bubble-free FP. In this study, we investigate the FP of acrylate monomers of varying functionalities, including methyl methacrylate (MMA), 1,6-hexanediol diacrylate (HDDA), and trimethylolpropane triacrylate (TMPTA), using N,N-dimethylaniline/benzoyl peroxide (DMA/BPO) redox couple at room temperature and compare their front behavior, pot life, and bubble formation with those of same resin systems mixed with a conventional peroxide initiator, Luperox 231. The use of redox couples in FP of acrylates shows promise for rapid, energy-efficient manufacturing of polyacrylates and can enable new applications such as 3D printing and composite manufacturing.

DEGRADATION KINETICS OF TEXTILE AZO DYE REACTIVE ORANGE-16 BY GAMMA IRRADIATION

Gamma radiation have become attention since their high potential for degrading compounds, especially organic pollutants. In this research, gamma radiation was studied for degrading the Reactive Orange-16 (RO-16) dye, a toxic and carcinogenic pollutant. The radiolytic degradation process was studied in a batch reactor with a gamma-ray dose rate of 2.930 kGy/h. The effect of experimental variable such as initial peroxide concentration, initial pH, initial dye concentration, and addition of inorganic anion were studied. The highest degradation rates were achieved at a peroxide concentration ranging from 2 to 4 mM. In contrast, the higher peroxide concentration indicated the slower degradation process caused by the scavenging effect of the peroxide. Degradation of 88% RO-16 dye with 0.1 mM initial concentration, was achieved at 2.0 kGy irradiation dose and 97.4% degradation in the presence of 4 mM peroxide. The dose constant (d) for those degradation processes was 1.0657 kGy-1 and 1.8420 kGy-1 respectively. The degradation was more efficient in acid pH. The degradation process increased with lower initial dye concentrations. The degradation of RO-16 dye by gamma-ray was inhibited by the presence of inorganic anions in the following sequence: NO3-→ CO32− → HCO3− → CH3COO-→ Cl-.

Analysis of Intact In Vivo Peroxidized Phospholipids from Bovine Retina via LC-MS/MS and GC-MS/MS Using Autoxidized Retina Reference Standards.

Highly unsaturated fatty acids (HUFAs) are vulnerable to oxygen attack, thus making HUFA-rich, high metabolic rate/reactive oxygen species (ROS)-generating neurological tissue particularly susceptible to increased oxidative stress. Lipid oxidation is a putative early stage marker of neurodegenerative diseases, suggesting that reliable monitoring of oxidized neural lipids in vivo reveals early pathogenesis. Here, we present a novel methodology to detect and quantify intactin vivo ROS-driven peroxidized phospholipids (LPOx-PLs) in bovine retina extract. A protocol for preparing autoxidized pure phospholipids (PLs) and complex retinal extracts served as reference standards and was adapted to enable analytical parameter development. Fatty acid profiles of bovine retinas were first established with routine gas chromatography (GC) methods and used to customize mass spectrometry scanning for major HUFA-carrying PLs in the retinal extract. Targeted multiple reaction monitoring (MRM) scanning via triple quadrupole tandem mass spectrometry detected native (unoxidized) and oxidation-damaged PL regardless of the position of the O or O2 addition along the acyl chains and enabled quantification of relative signals from intact native and oxidized PL (5%-10% CV). MRM-triggered information-dependent acquisition (IDA) spectra confirmed the structure of peroxidized PLs, revealing that peroxidized species (+O-OH) dominated over single O-added species in vitro and in vivo. Positive identification and relative quantification are reported for 12 selected in vivo native and peroxidized phosphatidylcholines and phosphatidylethanolamines. These results enable future studies of the initial peroxidation due to toxins, genetics, or other initiating events influencing in vivo oxidation levels and potentially the effectiveness of strategies to mitigate this mechanism of action.

Investigation of the Influence of Copovidone Properties and Hot-Melt Extrusion Process on Level of Impurities, In Vitro Release, and Stability of an Amorphous Solid Dispersion Product.

Hot-melt extrusion (HME) is a widely used method for creating amorphous solid dispersions (ASDs) of poorly soluble drug substances, where the drug is molecularly dispersed in a solid polymer matrix. This study examines the impact of three different copovidone excipients, their reactive impurity levels, HME barrel temperature, and the distribution of colloidal silicon dioxide (SiO2) on impurity levels, stability, and drug release of ASDs and their tablets. Initial peroxide levels were higher in Kollidon VA 64 (KVA64) and Plasdone S630 (PS630) compared to Plasdone S630 Ultra (PS630U), leading to greater oxidative degradation of the drug in fresh ASD tablets. However, stability testing (50 °C, closed container, 50 °C/30% RH, open conditions) showed lower oxidative degradation impurities in ASD tablets prepared at higher barrel temperatures, likely due to greater peroxide degradation. Plasdone S630 is suitable for ASDs with drugs prone to oxidative degradation, while standard purity grades may benefit drugs susceptible to free radical degradation, as they generate fewer free radicals post-HME. ASD tablets exhibited greater physical stability than milled extrudate samples, likely due to reduced exposure to stability conditions within the tablet matrix. Including SiO2 in the extrudate composition resulted in greater physical stability of the ASD system in the tablet; however, it negatively affected chemical stability, promoting greater oxidative degradation and hydroxylation of the drug substance. No impact of the distribution of SiO2 on drug release was observed. The study also confirmed the congruent release of copovidone, the drug substance, and Tween 80 using flow NMR coupled with in-line UV/vis. This research highlights the critical roles of peroxide levels and SiO2 in influencing the dissolution and physical and chemical stability of ASDs. The findings provide valuable insights for developing stable and effective pharmaceutical formulations, emphasizing the importance of controlling reactive impurities and excipient characteristics in ASD products prepared by using HME.

Comprehensive kinetic investigation of antiradical activity of urolithins and their potential inhibitory effect on Xanthine Dehydrogenase

This work aimed to explore the antiradical activity of various ellagitannin metabolites, including Urolithin A (UroA), Urolithin B (UroB), Urolithin C (UroC), and Urolithin D (UroD), in a non-polar (benzene) and polar (water) medium. The antiradical effect of the investigated compounds against reactive oxygen species HO• was evaluated in water (physiological conditions) and benzene, while against CH3OO• and CCl3OO• it was assessed solely in benzene, using the Quantum Mechanics-based Test for Overall Free-radical Scavenging Activity (QM-ORSA) methodology. In non-polar media, compounds UroA, UroC, and UroD exhibit antiradical capabilities against the HO• through Proton-coupled electron transfer (PCET) and Radical Adduct Formation (RAF) processes. Conversely, UroB predominantly exhibits inhibitory activity on HO• through the RAF pathway. On the other hand, the reaction with CH3OO• and CCl3OO• only occurs through the Hydrogen Atom Transfer (HAT). Under physiological conditions, all investigated compounds show antiradical capacity against the HO•, primarily via the SPLET and RCF mechanisms. The reactivity of radical species in both solvents decreases in the following order: HO• > CCl3OO• > CH3OO•. The thermodynamic and kinetic parameters in both solvents indicate that the investigated compounds’ reactivity follows a decreasing order of UroD > UroA > UroC > UroB. Furthermore, newly formed radical species of urolithin exhibit lower reactivity towards the fatty acid model in comparison to investigated reactive radical species, potentially preventing lipid peroxidation initiation. The investigated compounds can regenerate glutathione (GSH) by providing a hydrogen atom to the glutathione radical (GS•), which forms during interaction with highly reactive radical species. In water, tested compounds also regenerate GSH by donating H atoms to GS•, as well as by transferring electrons from dominant acid-base species to GS•, followed by protonation of the resulting GS¯. Urolithins showed similar inhibitory effects as the conventional inhibitors Y-700, FYX-051, and Febuxostat on Xanthine Dehydrogenase (XDH). Reactivity towards XDH enzyme decreases in the following order UroC > UroB > UroD > UroA.

Lipid-derived electrophiles inhibit the function of membrane channels during ferroptosis

The therapeutic targeting of ferroptosis requires full understanding of the molecular mechanism of this regulated cell death pathway. While lipid-derived electrophiles (LDEs), including 4-hydroxy-2-nonenal (4-HNE), are important biomarkers of ferroptosis, a functional role for these highly reactive species in ferroptotic cell death execution has not been established. Here, through mechanistic characterization of LDE-detoxification impairment, we demonstrate that LDEs mediate altered protein function during ferroptosis. Applying live cell fluorescence imaging, we first identified that export of glutathione-LDE-adducts through multidrug resistance-associated protein (MRP) channels is inhibited following exposure to a panel of ferroptosis inducers (FINs) with different modes of action (type I-IV FINs erastin, RSL3, FIN56, and FINO2). This channel inhibition was recreated by both initiation of lipid peroxidation and treatment with 4-HNE. Importantly, treatment with radical-trapping antioxidants prevented impaired LDE-adduct export when working with both FINs and lipid peroxidation initiators but not 4-HNE, pinpointing LDEs as the cause of this inhibited MRP activity observed during ferroptosis. Our findings, when combined with reports of widespread LDE alkylation of key proteins following ferroptosis induction, including MRP1, set a precedent for LDEs as critical mediators of ferroptotic cell damage. Lipid hydroperoxide breakdown to form truncated phospholipids and LDEs may fully explain membrane permeabilization and modified protein function downstream of lipid peroxidation, offering a unified explanation of the molecular cell death mechanism of ferroptosis.

Impact of the functionalized clay nanofillers on the properties of the recycled polyethylene terephthalate nanocomposites

AbstractPolymer nanocomposites, such as polyethylene terephthalate (PET)‐clay systems, leverage intricate interactions between components to fine‐tune their thermal, mechanical, and rheological properties. In our study, we functionalized montmorillonite clay nanofillers (CloisiteNa+) to fabricate recycled PET‐clay nanocomposites. The nanofillers underwent a three‐step functionalization process, involving the treatment with (3‐Aminopropyl)triethoxysilane (APTES), the grafting of initiating coatings (multifunctional peroxide initiator, [MPI]) onto clay/APTES, and the subsequent fabrication of grafted brushes using poly(butyl methacrylate) (PBMA) or poly(butyl acrylate) (PBA). The functionalization process and the properties of the modified clay were successfully confirmed through Fourier‐transform infrared spectroscopy and thermogravimetric analysis. The fabrication of nanocomposites, incorporating both clay and functionalized clay, influenced the thermal behavior of the composites, whereas the nanofillers had no discernible impact on the flow temperature. The PET and nanocomposites exhibited liquid viscoelastic behavior, with the exception of PET with clay, which displayed shear‐thinning and “rubber‐like” behavior. Rheological curves and x‐ray diffraction (XRD) analysis indicated improved dispersion and compatibility for clay/APTES and clay functionalized with PBA‐grafted brushes within the PET matrix. In some instances, the utilization of functionalized clay resulted in enhanced compatibility and customized properties in PET‐organoclay nanocomposites compared with conventional fillers. These findings bear implications for a broad spectrum of applications involving PET‐organoclay nanocomposites.

Heterogeneous Photo-Fenton-like Degradation of Oxytetracycline Containing Wastewater

Oxytetracycline (OTC) is a commonly used antibiotic. It can be absorbed to a limited extent by both humans and animals, so it can be detected at various levels in different water sources. Its presence in rivers or water and wastewater streams can pose serious problems for human and environmental health, and therefore, it needs to be treated. OTC degradation was studied using iron-doped g-C3N4 through a photo-Fenton-like oxidation process under simulated sunlight. In this study, the effects of key reaction parameters such as pH (3, 6, 9), catalyst amount (0-0.8 g/L), initial hydrogen peroxide concentration (HP, 0-20 mM) on the degradation of oxytetracycline were studied. The optimal reaction conditions for OTC degradation were found to be pH=6, catalyst amount of 0.4 g/L, and HP of 10 mM. Subsequently, the temperature effect was examined at the optimum reaction conditions. Based on the results, at 25, 35, and 45 °C, OTC degradation was found to be 51.1%, 60.8%, and 76.7%, respectively. The kinetic study conducted revealed that the observed reaction follows a second-order reaction kinetic model. In addition, the activation energy of observed reaction was found to be 86.96 kJ/mol.

Preparation of Low-Molecular-Weight Polyacrylamide as the Delayed Crosslinking Plugging Agent for Drilling Fluid.

Deep wells and ultra-deep wells often encounter cracks, karst caves, and other developed strata, which can lead to leakage during drilling. Conventional bridge slurry plugging technology is prone to leaking due to the poor plugging effect of the plugging agent. The gel plugging agent possesses characteristics of flexible plugging and adaptive matching of formation leakage channels. It can fill cracks or caves and enhance the pressure-bearing capacity of the formation. A controllable crosslinking plugging agent based on low-molecular-weight polyacrylamide was studied. Polyacrylamide with different molecular weights is synthesized from acrylamide and an initiator. A crosslinking time-controllable polymer is synthesized from low-molecular-weight polyacrylamide by adding crosslinking agent and retarder. The low-molecular-weight polyacrylamide plugging agent has low viscosity before gelation and good fluidity in the wellbore. After being configured on the ground, it is transported by pipeline and sent underground to reach the thickening condition. The gel solution rapidly solidifies, and its strength improves after high-temperature crosslinking. The synthesis conditions of the polymer were as follows: a monomer concentration of 9%, initiator 3.5%, synthesis temperature of 65 °C, and hydrogen peroxide initiator. The optimal formula of the gel plugging agent is as follows: a polymer concentration of 6%, a crosslinking agent concentration of 1%, and a retarder concentration of 8%. The generated polymer molecular structure contains amide groups. This crosslinking time-controllable plugging agent based on low-molecular-weight polyacrylamide has stable rheology, and its temperature resistance can reach 150 °C. At 150 °C, the gelation time can be controlled by adjusting the concentration of retarder, and the longest can reach 4 h. The plugging efficiency of the gel plugging agent is more than 95%. With the increase in seam width, the pressure of the gel plugging agent gradually decreases.

A performance comparison of photo-fenton decolorization of methylene blue by using bentonite/iron composites prepared by liquid phase and solid phase ion exchange method

Nowadays, there is a wide range of pollutants present, which requires the treatment of wastewater. The photo-Fenton method has been recognized as valuable in this area. In this study, iron/bentonite composites were created using both liquid phase and solid phase iron exchange techniques, and they were utilized as a photocatalyst for the degradation of methylene blue through photo-Fenton process. Various factors affecting the photocatalytic decolorization were investigated, including the initial concentration of the dye, weight of the catalyst, pH of the solution, and concentration of hydrogen peroxide. The decolorization efficiency of the iron/bentonite composites prepared using the solid phase and liquid phase ion exchange approaches was found to be 99% and 95%, respectively. Based on the data, it can be concluded that the performance of both catalysts was almost equally influenced by the initial dye concentration, catalyst weight, solution pH, and hydrogen peroxide concentration. Moreover, the solid phase ion exchange method demonstrated greater reusability compared to the liquid phase ion exchange method. Consequently, it can be stated that the solid phase ion exchange approach is a suitable and straightforward alternative to the conventional liquid phase ion exchange method for producing a photo-Fenton catalyst.

Unravelling the thermal behavior and kinetics of unsaturated polyester resin supplemented with organo-nanoclay.

The integration of nanoclays within polymeric systems to develop high-performance materials is an emerging research field that has garnered significant attention. In this context, an organically modified montmorillonite (OMMT) is utilized as a reinforcing agent for unsaturated polyester resin (UPR) with loads of 1%, 3%, and 5 wt%. The modification of montmorillonite nanoclay (MMT) using a quaternary ammonium compound is performed through an effective repetitive modification process under reflux conditions. The curing behavior of the unsaturated polyester resin containing organically modified clay catalyzed with methyl ethyl ketone peroxide (MEKP) initiator and promoted by cobalt naphthenate accelerator is investigated using dynamic differential scanning calorimetry (DSC) followed by kinetic analysis using isoconversional methods. The dynamic DSC curing curves showed a bimodal exothermic peak, where two independent reactions, namely, redox and thermal decomposition of the initiator occurred. In this study, novel insights into the curing reaction of the studied UPR and UPR/OMMT systems have been revealed through the application of the Trache-Abdelaziz-Siwani (TAS) and Sbirrazzuoli (VYA/CE) isoconversional methods. These methods have enabled the elucidation of the intricate mechanisms and phenomena that impact the curing reaction, including the dilution effect in the redox reaction and the diffusion phenomenon at the end of the thermal decomposition reaction. The incorporation of nanoclay into unsaturated polyester resin (UPR) resulted in a reduction in the activation energy for both the redox and thermal reactions. Specifically, the energetic barrier decreased from 93.85 and 101.58 kJ mol-1 for pristine UPR to 60.71 and 72.93 kJ mol-1 for UPR/OMMT-5 in the redox and thermal reactions, respectively. The addition of OMMT caused a significant decrease in the pre-exponential factor. The values of UPR/OMMT-5 were 2.75 × 105 and 5.50 × 106 for the redox and thermal decomposition reactions, respectively, compared to 1.41 × 1012 and 5.13 × 1013 for UPR. The thermogravimetric analysis demonstrated that UPR/OMMT systems were more stable than UPR.

Sandwich-type channeled chemical hydrogels manufactured by 3D ink-jet printing under freezing conditions using a photochemical process for human cell cultures

This work aims to present the technology of preparing chemical hydrogels for cell culture by printing. It consists in drop-on-drop 3D ink-jet printing under freezing conditions of a solution containing a diacrylic compound (poly(ethylene glycol) diacrylate (PEGDA)) with an initiator (hydrogen peroxide) of photochemically induced polymerization and cross-linking. 3D printing takes place at a low temperature, thanks to which droplets of the solution immediately freeze, allowing the desired structures of the frozen solution to be built. UVC radiation of frozen structures at room temperature and in the presence of oxygen induces simultaneous melting and radical polymerization and cross-linking of PEGDA, resulting in the formation of a firm chemical hydrogel with the same shape as the shape of the printed frozen solution. Discussed are: (i) technological parameters, (ii) reaction mechanism, (iii) sol–gel analysis, (iv) morphology of printed hydrogels and (v) biocompatibility studies with the applied human fibroblasts, human umbilical vein endothelial cells and human neuroblastoma cells. A method for printing sandwich-type channeled structures was developed and shown in application for cell growth. This work demonstrates the feasibility of 3D printing biocompatible chemical hydrogels for cell culture and opens new possibilities for printing hybrid structures for biomedical applications.

Preparation of hydrocarbon resins by suspension oligomerisation of the C9 fraction of gasoline pyrolysis initiated by amino peroxides

The object of research is the production of C9 hydrocarbon resins by oligomerization of oil refining by-products. In the technology of hydrocarbon resins by free radical oligomerization, there is a disadvantage in the use of high temperatures and a long reaction time. The resulting products have a dark color, which limits their use in paints and varnishes. The technology of hydrocarbon resins, which consists in the suspension oligomerization of hydrocarbons of the C9 fraction in an aqueous medium, at low temperatures and stirring, was studied. N-substituted amino peroxides, which are characterized by a low temperature of use, were used as initiators. The raw materials used were C9 fractions of liquid gasoline pyrolysis products with an unsaturated compound content of 54.7 %. The optimal conditions were established: temperature – 364 K, time – 180 min, Re=10120, initiator concentration – 0.064 mol/l, the share of C9 fraction in the reaction mixture – 25 %. Under these conditions, a light hydrocarbon resin with a color index of 20 mg I2/100 ml and a softening point of 352 K was obtained. The use of amino peroxide initiators allows for the suspension oligomerization of the hydrocarbon fraction C9 at low temperatures (303–353 K) and within a short reaction time (180 min). This oligomerization technology makes it easy to remove excess heat and maintain isothermal conditions in the reaction zone. This prevents the development of side oxidation reactions that cause darkening of the product. The research results make it possible to improve the process of oligomerization of the hydrocarbon fraction using new initiators and obtain light-colored hydrocarbon resins. This will reduce energy costs for production and improve the characteristics of hydrocarbon resins

Asphalt Modification with LDPE Plastic Waste Treated with Glacidyl Methacrylate and Benzoyl Peroxide Initiator

The aim of this research is to determine the quality of the softening point test, penetration test and deactivation of modified asphalt from garfted LDPE plasticization waste. And for grafting treatment, use the internal mixer method where GMA and BPO are added to the grafting mixture. From the grafting results obtained, we carried out an FTIR test and identified a wave number of 1728/cm indicating the presence of the C-H or benzene functional group. This can be interpreted as a grafting process which can also be seen at the wave number 1730/cm. This can be interpreted as a grafting process from GMA to LDPE. And for the wave number at 2723/cm, there is a CH3 stetching from the LDPE chain backbone so that what is obtained is the LDPE-g-GMA spectrum. As for the TGA and DSC test results obtained, namely that in DSC the peak value of the number is at a temperature of 160.60 C and the value obtained from TGA is 373.13 C. And to find out the standard of modified asphalt from mixing asphalt with waste The value of the grafted plastic that we carried out was 65.23, for the penetration test it was 53.7 and for the deactivation test it was 55.46. This can be interpreted that all three are in accordance with the 2018 Bina Marga asphalt standards

Experimental and Numerical Study of Healing Effect on Delamination Defect in Infusible Thermoplastic Composite Laminates.

The integrity of delaminated composite structures can be restored by introducing a thermally-based healing effect on continuous fiber-reinforced thermoplastic composites (CFRTPC). The phenomenon of thermoplastics retaining their properties after melting and consolidation has been applied by heating the delaminated composite plates above their glass transition temperature under pressure. In the current investigation, the composite is comprised of Methyl methacrylate (MMA)-based infusible lamination resin combined with benzoyl peroxide initiator, which polymerizes into a Polymethyl methacrylate (PMMA) matrix. For the reinforcement, unidirectional 220 gr/m2 glass filament fabric was used. Delamination damage is artificially induced during the fabrication of laminate plates. The distributed delamination region before and after thermally activated healing was determined by using non-destructive testing with active thermography. An experimental approach is employed to characterize the thermal healing effect on mechanical properties. Experimentally determined technological parameters for thermal healing have been successfully applied to repair delamination defects on composite plates. Based on the compression-after-impact (CAI) test methodology, the intact, damaged, and healed composite laminates were loaded cyclically to evaluate the healing effect on stiffness and strength. During the CAI test, the 3D digital image correlation (DIC) technique was used to measure the displacement and deformation fields. Experimental results reveal the difference between the behavior of healed and damaged specimens. Additionally, the numerical models of intact, damaged, and healed composite laminates were developed using the finite element code LS-Dyna. Numerical models with calibrated material properties and tie-break contact constants provide good correlation with experimental results and allow for the prediction of the mechanical behavior of intact, damaged, and healed laminated plates. The comparison analysis based on CAI test results and modal characteristics obtained by the 3D Laser Doppler Vibrometer (Polytec GmbH, Karlsbad, Germany) proved that thermal healing partially restores the mechanical properties of damaged laminate plates. In contrast, active thermography does not necessarily indicate a healing effect.

Catalytic degradation of crystal violet and methyl orange in heterogeneous Fenton-like processes

Metals-loaded (Fe3+, Cu2+ and Zn2+) activated carbons (M@AC) with different loading ratios (0.1%, 0.5%, 1%, 5% and 10%) were prepared and employed for catalytic degradation of dye model compounds (crystal violet (CV) and methyl orange (MO)) in wastewater by heterogeneous Fenton-like technique. Compared with Cu@AC and Zn@AC, 0.5% Fe3+ loaded AC (0.5Fe@AC) had better catalytic activity for dyes degradation. The effects of dyes initial concentration, catalyst dosage, pH and hydrogen peroxide (H2O2) volume on the catalytic degradation process were investigated. Cyclic performance, stability of 0.5Fe@AC and iron leaching were explored. Degradation kinetics were well fitted to the pseudo-second-order model (Langmuir-Hinshelwood). Almost complete decolorization (99.7%) of 400 mg L−1 CV was achieved after 30 min reaction under the conditions of CV volume (30 mL), catalyst dosage (0.05 g), H2O2 volume (1 mL) and pH (7.7). Decolorization of MO reached 98.2% under the same conditions. The abilities of pyrolysis char (PC) of dyeing sludge (DS) and metal loaded carbon to remove dye pollutants were compared. The intermediate products were analyzed and the possible degradation pathway was proposed. This study provided an insight into catalytic degradation of triphenylmethane- and aromatic azo-based substances, and utilization of sludge char.

A Comprehensive and Sustainable Recycling Process for Different Types of Blended End-of-Life Solar Panels: Leaching and Recovery of Valuable Base and Precious Metals and/or Elements

The production of photovoltaic modules is increasing to reduce greenhouse gas emissions. However, this results in a significant amount of waste at the end of their lifespan. Therefore, recycling these solar panels is important for environmental and economic reasons. However, collecting and separating crystalline silicon, cadmium telluride, and copper–indium–gallium–selenide panels can be challenging, especially in underdeveloped countries. The innovation in this work is the development of a process to recycle all solar panel waste. The dissolution of all metals through the leaching process is studied as the main step of the flowchart. In the first step of leaching, 98% of silver can be recovered by 0.5 M nitric acid. Then, the second and third step involves the use of glycine for base metal dissolution, followed by the leaching of valuable metals with hydrochloric acid. The effect of parameters such as the initial pH, acid concentration, solid/liquid ratio, and hydrogen peroxide concentration is studied. The results show that up to 100% of Cu, Pb, Sn, Zn, Cd, In, Ga, and Se can be recovered under optimal conditions. The optimal conditions for the dissolution of Cu, Zn, and Cd were a glycine concentration of 0.5 M, a temperature of 25 °C, a solid/liquid ratio of 10 gr/L, and 1% of hydrogen peroxide. The optimized glycine concentration for the leaching of lead and tin was 1.5 M. Indium and gallium were recovered at 100% by the use of 5 M hydrochloric acid, S/L ratio = 10 gr/L, and T = 45 °C. Separation of selenium and tellurium occurred using 0.5 M HCl at a temperature of 60 °C. Additionally, for the first time, a general outlook for the recycling of various end-of-life solar panels is suggested.

Gerçek Tekstil Atıksularının Perovskite/Aktif Karbon Kompozit Katalizör Varlığında Elektrokoagülasyon ve Fenton Benzeri Oksidasyondan Oluşan Hibrit Sistem Kullanılarak Son Arıtımı

A hybrid wastewater treatment method was used to improve the quality of the treated wastewater for possible reuses. Real textile wastewater was subjected to electrocoagulation and Fenton like oxidation sequentially. In the Fenton like oxidation process the performances of BiFeO3/RHAC and BiNiO3/RHAC (RHAC: Rice husk based activated carbon) catalysts were compared. BiNiO3/RHAC was determined to be more effective in total organic carbon removal. A parametric study was carried out in the presence of the selected BiNiO3/RHAC catalyst to investigate the effect of the catalyst loading, pH and the oxidant dosage on total organic carbon removal. The most suitable reaction conditions were determined as 1.5 g/L of catalyst loading, pH 7, and 2 mM initial hydrogen peroxide concentration. 17% and 15.7% total organic removal efficiencies were achieved in electrocoagulation and Fenton like oxidation processes, respectively, whereas the cumulative removal efficiency was 32.7%.