Peroxide Oxidation Research Articles

Surface oxidation of commercial activated carbon with enriching carboxyl groups for high-yield electrocatalytic H2O2 production

Two-electron oxygen reduction reaction (2e− ORR) for H2O2 production is regarded as a more ecologically friendly substitute to the anthraquinone method. However, the search of selective and cheap catalysts is still challenging. Herein, we developed a neutral-selective and efficient nonprecious electrocatalyst that was prepared from a commercial activated carbon (AC) by simply microwave-assisted ash impurity elimination and hydrogen peroxide oxidation for surface functional sites optimization. The oxygen configuration can be tuned with enriching carboxyl group up to 6.65 at.% by the dosage of hydrogen peroxide (mass ratio of H2O2/C = ∼0–8.3). Chemical titration experiments identified the carbonyl groups as the most potential active sites, with selectivity boosted by the additional carboxyl groups. The microwave-assisted moderate-oxidized activated carbon (MW-AC5.0) demonstrated optimal 2e− ORR activity and selectivity in neutral electrolyte (0.1 M K2SO4), with H2O2 selectivity reaching ∼75%–97%, a maximum H2O2 production rate (1.90 mol·gcatal −1·h−1@0.1 V) and satisfying faradaic efficiency (∼85%) in gas-diffusion-electrode. When coupled with Fenton reaction, it can degrade a model organic pollutant (methylene blue [MB], 50 ppm) to colorless in a short time of 20 min, indicating the potential applications in the environmental remediation.

Nitric oxide and hydrogen sulfide alleviates salt incited oxidative stress in Coriandrum sativum L

Soil salinity accelerates osmotic, ionic and oxidative pressure that suppresses plant growth and crop production. The objective of of the present investigation was to analyse protective function of nitric oxide (NO) and hydrogen sulfide (H2S) against salt (NaCl) stress in coriander plants. Different morphological, biochemical parameters, enzymatic and non-enzymatic antioxidants were analysed. Exposure of Coriandrum sativum L. to NaCl reduced length of root and shoot, biomass, relative water content and biochemical attributes. Exogenous use of SNP and NaHS individually or in combined treatment increased all the above-mentioned growth variables and inhibited NaCl incited biochemical alterations and oxidative damages in Coriandrum sativum L. Synergistic treatment (SNP + NaHS) exhibited increase in the morphological parameters, pigment and osmolyte contents. The oxidative stress biomarkers, hydrogen peroxide and superoxide generation were declined by SNP and NaHS as evidenced by reduced peroxidation of lipids. Activities of both glyoxylase as well as antioxidant enzymes were enhanced with presence of SNP and NaHS. Coriander seedlings treated with NaCl + SNP + NaHS exhibited 21 %, 7 %, 31 % and 59 % increase in superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), respectively over NaCl treated plants. Level of methylglyoxal was decreased in Coriandrum sativum with rise in glyoxalase I and II enzymes. Therefore, synergistic supplementation of NO and H2S alleviates salt stress in coriander plants more efficiently than individual treatment and it might be because of crosstalk mechanism that facilitate salt stress resistance in plants.

Membrane-stabilizing properties of Viburnum opulus fruit liquid extract and cardioprotective effect of tablets based on it

Aim. To study the membrane-stabilizing properties of Viburnum opulus fruit liquid extract (VOFLE) and the cardioprotective activity of “Viburnikor” tablets developed on the basis of VOFLE. Materials and methods. Membrane-stabilizing properties of VOFLE were studied according to the Jager F.C. method in rats with determination of the spontaneous hemolysis degree caused by peroxide oxidation of erythrocyte membranes lipids. VOFLE (50, 100, 150 mg/kg), reference drugs Quercetin (200 mg/kg) and vitamin E (50 mg/kg) were administered to animals intragastrically (i/g) for 7 days. Adrenaline myocardiodystrophy was reproduced in rats by a single subcutaneous injection of adrenaline hydrochloride (0.18 % solution) in the dose of 0.5 mg/kg (0.28 ml/kg) of the body weight. Thirty (30) white male rats with an initial weight of 230-270 g, aged 6-6.5 months were used in the experiment. “Viburnikor” tablets (100 and 150 mg/kg of the VOFLE content) and Quercetin (200 mg/kg) were administered i/g for 7 days, the last time 1 hour before the cardiotoxin administration. The activity of the drugs was evaluated by the survival of animals, the functional state of the myocardium (ECG studies), the effect on the heart mass ratio, the activity of aspartate aminotransferase (AST), the level of active products interacting with thiobarbituric acid (TBA-AP), the content of reduced glutathione (RG) and catalase activity in the heart homogenate. Results and discussion. The VOFLE studied showed the most pronounced membrane-stabilizing effect in the doses of 100 and 150 mg/kg, respectively, 22 and 34 %, the intensity of which was not inferior to the reference drugs Quercetin (26 %) and vitamin E (28 %). On the model of catecholamine myocardiodystrophy, “Viburnikor” tablets (100 and 150 mg/kg) contributed to the improvement of the heart function, as evidenced by the normalization of electrocardiographic parameters and heart mass ratio to the level of intact animals. It has been shown that the cardioprotective properties of “Viburnikor” tablets are exhibited by detecting anticytolic (decrease in the AST activity to the level of intact control) and antioxidant action (decrease in the level of TBA-AP in the myocardium of animals by 31 % (p<0.05) and 33 % (p<0.05), respectively, and a 1.6- and 1.7-fold increase in RG (p<0.05) and catalase (p<0.05) versus the control pathology). Conclusions. It has been proven that the most pronounced membrane-stabilizing effect of the VOFLE studied is in the doses of 100 and 150 mg/kg. Cardioprotective properties of “Viburnikor” tablets have been determined on the model of catecholamine myocardiodystrophy by revealing anticytolic and antioxidant effects. By the intensity of the membrane-stabilizing and cardioprotective activity of the drugs studied, VOFLE and “Viburnikor” tablets are not inferior to the reference drugs.

Profiling of tyrosinase levels, antioxidant and DNA protective properties in different edible and medicinal mushroom species from India

AbstractBackgroundTyrosinase is a polyphenol oxidase, one of the globally attracted enzymes for its multi‐mechanistic approaches in various fields such as pharma, food, environment, medicine, and agriculture. Tyrosinase from natural nutritive edible mushrooms gained more attention for their rich levels and inexpensive nature. Our previous work has revealed that mushroom tyrosinase has strong similarities in structure and function with that of skin tyrosinase, which has significance as a skin tumor marker. Besides, mushrooms are a richer source of antioxidants. However, it is imperative to analyze all the available varieties of mushrooms for bioactive potentials like tyrosinase and antioxidant levels. Thus, the main goal of the study was to identify the variety of mushrooms that can be selected for continuous multiplication and propagation as a viable source for tyrosinase, which can be employed to screen tyrosinase inhibitors as skin tumor inhibitors.ResultsOf the 18 varieties screened for tyrosinase levels, Boletus edulis, Termitomyces hemii, and Termitomyces mummiformis had high levels of tyrosinase and exhibited potent hydrogen peroxide and nitric oxide scavenging activity as well as DNA protection. The potent DNA and antioxidant abilities appear to be due to the enriched levels of hydroxybenzoates.ConclusionThe current study could provide an economic source of tyrosinase (mushrooms) that can be used to monitor tyrosinase inhibitors, a potent component that enables their use against skin cancer.

Preparation of PrFexCo1–xO3/Mt catalyst and study on degradation of 2-hydroxybenzoic acid wastewater by catalytic wet peroxide oxidation

In this study, the perovskite nanocomposite PrFexCo1–xO3(Pr(S)) was successfully synthesized by the sol–gel method; PrFexCo1–xO3/Al-pillared montmorillonite (Pr(S)/Mt) catalysts were prepared by impregnation (D) method and solid-melting (G) method, respectively, with Pr(S) as the active component and Al-pillared montmorillonite as the carrier. The catalysts were applied to treat the 2-hydroxybenzoic acid (2-HA)-simulated wastewater by catalytic wet peroxide oxidation (CWPO) technique, and the chemical oxygen demand (COD) removal rate and the 2-HA degradation rate were used as indicators to evaluate the catalytic performance. The results of the experiment indicated that the solid-melting method was more conducive to preparing the catalyst when the Co/Fe molar ratio of 7:3 and the optimal structural properties of the catalysts were achieved. The influence of operating parameters, including reaction temperature, catalyst dosage, H2O2 dosage, pH, and initial 2-HA concentration, were optimized for the degradation of 2-HA by CWPO. The results showed that 97.64% of 2-HA degradation and 75.23% of COD removal rate were achieved under more suitable experimental conditions. In addition, after the catalyst was used five times, the degradation rate of 2-HA could still reach 76.93%, which implied the high stability and reusability of the catalyst. The high catalytic activity of the catalyst was due to the doping of Co into PrFeO3, which could promote the generation of HO·, and the high stability could be attributed to the loading of Pr(S) onto Al–Mt, which reduced the leaching of reactive metals. The study of reaction mechanism and kinetics showed that the whole degradation process conformed to the pseudo-first-order kinetic equation, and the Langmuir–Hinshelwood method was applied to demonstrate that catalysis was dominant in the degradation process.

The impact of dimethylformamide on the synthesis of graphene quantum dots derived from graphene oxide

Graphene quantum dots (GQDs) have garnered immense interest in recent years due to their unique optical, electrical, and chemical properties, making them promising candidates for various applications in optoelectronics, bioimaging, and sensing. However, enhancing the control over the size, surface chemistry, and optical properties of GQDs remains a significant challenge. In this study, a novel recipe was proposed to successfully synthesize various GQDs via a typical solvothermal process, which has proven to be a versatile and scalable approach. In addition to the main ingredient – graphene oxide suspension, dimethylformamide (DMF) and hydrogen peroxide serving as a cutting agent were added to the reaction mixture. This synthesis method was found to be more promising than the reference one in which DMF was replaced by double distilled water. Through systematic experimentation, we demonstrated that the addition of DMF enables the successful GQD production over a wider range of reaction times; hence, the UV absorption band and photoluminescence properties of GQDs can be better adjusted. The dependence of photoluminescence on the excitation wavelength was observed in the as-prepared materials as they were excited with a range of wavelengths from 360 to 480 nm. The obtained insights not only advance our understanding of GQD synthesis but also open up avenues for tailoring their properties for specific applications.

Phase variation modulates the multi-phenotypes displayed by clinical Campylobacter jejuni strains

The high incidence and prevalence of Campylobacter spp. in the food supply chain entail the importance to understand their mechanisms developed to withstand harsh environmental conditions encountered. Different stress conditions and phenotypic approaches were evaluated to study the behaviour of five clinical C. jejuni isolates with different genotypes, including the tolerance to oxygen and the oxidants hydrogen peroxide and cumene hydroperoxide, the motility and the ability to form biofilm on polystyrene and stainless steel at different temperatures and atmospheres. Whole Genome Sequencing was performed to analyse the occurrence of 216 genes involved in these mechanisms plus phase variation. The isolates showed high tolerance to oxygen and peroxide stress with different swimming motility performances and biofilm formation abilities. Aerotolerance was related with a reduced sensitive to peroxide stress and a loss of motility that promotes biofilm formation depending on the material surface. Comparative genomics did not reveal any clear gene pattern, although phase variation occurring during host infection was observed to be crucial for the modulation of the different survival mechanisms adopted by the bacteria. These findings reveal that the bacteria can combine diverse and complex strategies in an efficient manner to survive and persist in the environment.

Exogenous Spermidine Regulates Ryegrass Root System Response to Cd Stress and Its Transcriptome Analysis

The application of exogenous growth-regulating substances is an effective technique to enhance plant stress tolerance. Here, a hydroponic experiment was conducted to investigate the effects of exogenous basal application of 0.1 mmol·L-1 spermidine (Spd) on both the physiology and molecular biology of ryegrass root systems under varying degrees (0, 5, and 10 mg·L-1) of cadmium (Cd) stress using ryegrass as the test plants. The results of physiological studies revealed that Cd stress significantly reduced the physiological functions of the ryegrass root system, whereas the addition of Spd effectively alleviated the negative effects caused by Cd. The most significant effect was on the root soluble protein content, which increased by 90.91% and 158.35% compared with 5 mg·L-1and 10 mg·L-1 Cd alone. Spd also inhibited the accumulation of oxidative stress products malondialdehyde (MDA) and hydrogen peroxide (H2O2) by increasing the ascorbic acid (ASA) and glutathione (GSH) content and peroxidase (POD) activity, whereas the effects on root activity and superoxide dismutase (SOD) activity were not significant. The results of molecular biology studies demonstrated that 10 mg·L-1 Cd stress caused differential expression of a large number of genes in ryegrass roots, and the number of differentially expressed genes, differential significance, and differential multiplicity were significantly reduced after the application of exogenous Spd. The most significant part of the GO enrichment analysis shifted from responding to organic cyclic compounds and aldehyde/ketone group transferase activity to responding to trivalent iron ions and 2'-deoxymugineic-acid 2'-dioxygenase activity. Single gene expression heat map analysis revealed that exogenous Spd upregulated the expression of genes encoding zinc-iron transporter protein and 2'-deoxymugineic-acid 2'-dioxygenase, which improved the uptake and utilization of iron by the root system. In conclusion, the application of certain concentrations of Spd could effectively regulate the response of ryegrass roots to Cd stress, enhance its tolerance physiology, and mitigate the toxic effects of Cd.

Combined approaches for detecting polypropylene microplastics in crop plants

Microplastics (MPs) pollution in the terrestrial environment causes accumulation in crop plants. Consumption of these plants may have negative effects on human health. Therefore, it is crucial to analyze MPs accumulation in the plants. The aim of this study is to determine polypropylene (PP) particles in plants exposed to label-free PP for 75 days. In order to extract PP from organic matter, a two-step alkaline and wet peroxide oxidation chemical digestion method was applied to the roots, stems, and leaves of maize and wheat. The PP particles in the digested solutions were detected by the Nile red staining method, which has not been used previously in the detection of MPs in plants. Nile red stained PP particles mostly accumulated in the roots of wheat and the stems of maize plants. Statistical analysis revealed that the maize deposited more and larger PP particles regardless of the location. Moreover, the presence of PP particles in the digestion solutions was proved by the heating method. The PP particles on the glass slides were transformed into different shapes due to melting.

Reactive oxygen species and gastric carcinogenesis: The complex interaction between Helicobacter pylori and host.

Helicobacter pylori (H. pylori) is a highly successful human pathogen that colonizes stomach in around 50% of the global population. The colonization of bacterium induces an inflammatory response and a substantial rise in the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), mostly derived from host neutrophils and gastric epithelial cells, which play a crucial role in combating bacterial infections. However, H. pylori has developed various strategies to quench the deleterious effects of ROS, including the production of antioxidant enzymes, antioxidant proteins as well as blocking the generation of oxidants. The host's inability to eliminate H. pylori infection results in persistent ROS production. Notably, excessive ROS can disrupt the intracellular signal transduction and biological processes of the host, incurring chronic inflammation and cellular damage, such as DNA damage, lipid peroxidation, and protein oxidation. Markedly, the sustained inflammatory response and oxidative stress during H. pylori infection are major risk factor for gastric carcinogenesis. In this context, we summarize the literature on H. pylori infection-induced ROS production, the strategies used by H. pylori to counteract the host response, and subsequent host damage and gastric carcinogenesis.

Extra- and intranuclear heat perception and triggering mechanisms in plants.

The escalating impact of global warming on crop yield and quality poses a significant threat to future food supplies. Breeding heat-resistant crop varieties holds promise, but necessitates a deeper understanding of the molecular mechanisms underlying plant heat tolerance. Recent studies have shed light on the initial events of heat perception in plants. In this review, we provide a comprehensive summary of the recent progress made in unraveling the mechanisms of heat perception and response in plants. Calcium ion (Ca2+), hydrogen peroxide (H2O2), and nitric oxide (NO) have emerged as key participants in heat perception. Furthermore, we discuss the potential roles of the NAC transcription factor NTL3, thermo-tolerance 3.1 (TT3.1), and Target of temperature 3 (TOT3) as thermosensors associated with the plasma membrane. Additionally, we explore the involvement of cytoplasmic HISTONE DEACETYLASE 9 (HDA9), mRNA encoding the phytochrome-interacting factor 7 (PIF7), and chloroplasts in mediating heat perception. This review also highlights the role of intranuclear transcriptional condensates formed by phytochrome B (phyB), EARLY FLOWERING 3 (ELF3), and guanylate-binding protein (GBP)-like GTPase 3 (GBPL3) in heat perception. Finally, we raise the unresolved questions in the field of heat perception that require further investigation in the future.

Heteronuclear Hexacyanometallate(III) Coordination Polymers (Cd/Cr, Cd/Fe, Cd/Co) with 3-(Aminomethyl)pyridine: Synthesis, Characterization, and Catalytic Activities for the Peroxidative Oxidation of Benzylic Alcohols

Heteronuclear Hexacyanometallate(III) Coordination Polymers (Cd/Cr, Cd/Fe, Cd/Co) with 3-(Aminomethyl)pyridine: Synthesis, Characterization, and Catalytic Activities for the Peroxidative Oxidation of Benzylic Alcohols

Postoperative infection problems in DBS applications

Deep brain stimulation (DBS) is a significant neuromodulation method for treating neurological and psychiatric disorders. Despite its efficacy, complications, particularly infections, are a concern. This article reviews the prevalence, risk factors, pathogens, infection locations, timing, surgical approaches, prevention strategies, and treatment methods associated with infections following DBS procedures. DBS surgeries have gained popularity due to their adjustability, but infections pose challenges. Surgical site infections (SSIs) are common (0% to 24% cases) and extensively studied regarding patient groups, locations, timing, and pathogens. Expanding patient groups, including conditions like Tourette syndrome and epilepsy, have varying infection risks. Infections occur at burr-hole, extension, and implantable pulse generator (IPG) sites. Staphylococcus aureus is a primary pathogen, yet bacterial DNA on IPGs and colonization complicate understanding. Surgical approaches, staged or non-staged, show comparable infection rates. The influence of repetitive pulse generator replacements on infection rates is debated. Lead externalization, topical vancomycin powder, and other factors impact infection risk. Treating DBS-related infections often requires hardware extraction and antibiotic treatment. Innovations like ethylene oxide sterilization and hydrogen peroxide show potential. Algorithms suggest partial explantation for localized infections. Cost analyses favor starting with antibiotics. Infections persist despite progress; understanding risks, pathogens, and strategies is vital for optimal outcomes in DBS.

Efficient Removal of Perfluorooctanoic Acid by UV-Based Peroxide and Persulfate Advanced Oxidation Processes

Perfluorooctanoic acid (PFOA) challenges traditional methods of aquatic treatment and recycling from recalcitrant organic compounds, which ubiquitously persist in the environment, mainly water bodies, and cause various adverse effects on humans and the environment. Conventional water treatment technologies are proven inefficient and must focus on advanced oxidation processes. This study conducted treatability studies for removing PFOA by direct photolysis, UV/peroxide, and UV/persulfate oxidation using a lab-scale reactor. The experiment was performed with an initial concentration of 20 mg/L for 120 min for a 500 mL of sample. The oxidant dosage and pH were optimized based on the mineralization efficiency. An efficient method for PFOA degradation is based on its percentage reduction in concentration, mineralization efficiency, and reaction kinetics study. It was found that all three processes were adequate for mineralizing PFOA. Among them, UV/persulfate was more effective in mineralizing PFOA. The total organic carbon removal percentages using direct photolysis, UV/persulfate, and UV/peroxide treatments were 49%, 80%, and 66%, respectively. The pseudofirst-order kinetics for these three were 0.160, 0.489, and 0.349 h−1, respectively.

Cobalt-H3BTC Metal Organic Framework-Based Electrochemical Nanosensor for Hydrogen Peroxide

Metal organic frameworks (MOFs) have found diverse applications in electrocatalysis and electrochemical sensing, owing to the presence of both metallic nodes and organic networks. Here, we electrosynthesized cobalt benzene tricarboxylate MOF inside an open carbon nanopipette (CNP) to produce a CNP-CoMOF nanoelectrode whose response is determined by Co(II)/Co(III) nodes attached to its porous nanostructure. Steady-state voltammograms of ferrocenemethanol at CNP-CoMOF nanoelectrodes exhibit a sigmoidal shape with a well-defined plateau current. A linear calibration curve obtained for the hydrogen peroxide oxidation suggests that CNP–CoMOF nanoelectrodes are potentially useful as nanosensors for peroxide free from interference of dissolved dioxygen.

Immunological Reactivity and Intensity of Oxidative Stress in Stable Coronary Artery Disease

The aim. To analyze the relationship between immune response factors and the intensity of oxidation of lipoproteins and proteins in patients with stable coronary artery disease (CAD) to clarify the pathogenesis of coronary atherosclerosis.
 Materials and methods. A total of 179 patients with stable CAD of II-IV functional class, mean age 56 (49-62) years (main group) and 30 healthy individuals, mean age 49 (45-53) years (control group) were examined. The material for immunological research was peripheral venous blood. To determine the indicators of immunity, flow laser cytometry and enzyme-linked immunosorbent assay were used. Spectrophotometric and fluorometric methods were used to determine the levels of intermediate and final oxidation products of lipids and proteins, as well as antioxidant protection enzymes in the blood serum and in atherogenic lipoproteins.
 Results. A direct relationship between the activity of lipoprotein peroxidation and protein oxidation with a cell-type immune response and immune inflammation was revealed.
 Conclusions. The high intensity of lipid peroxidation and protein oxidation in patients with stable CAD (stable angina pectoris) is combined with significant activation of the T-cell component of the immune response (in terms of the ratio of helper and cytotoxic subpopulations of T-lymphocytes, high concentrations of pro-inflammatory cytokines, the state of the CD40/CD40L system, the level of expression of the CD95 apoptosis marker on cells), which indicates interdependence of T-cell immunity and oxidative stress in the pathogenesis of atherosclerosis. The dependence of the hyperproduction of pro-inflammatory cytokines by mononuclear blood cells on free radical oxidation of proteins, peroxidation of apoB proteins and the intensity of antiperoxide protection (catalase and superoxide dismutase enzymes) in patients with stable CAD indicates a contribution to the presence of oxidative stress and the development of immune inflammation. A comprehensive study of the factors of immunological reactivity, the violation of which can lead to the development of immunopathological reactions, and the intensity of oxidation of lipoproteins and proteins in patients with stable CAD helps to clarify the pathogenetic relationship between chronic immune inflammation, endothelial dysfunction and oxidative stress, and also substantiates the expediency of general therapeutic approaches to the treatment of CAD.

Study on the mechanism of chemical mechanical polishing on high-quality surface of single crystal diamond

Due to the ultra-high hardness and excellent chemical inertness of single crystal diamond (SCD), achieving a high-quality surface of SCD by chemical mechanical polishing (CMP) is challenging. To obtain a high-quality surface of SCD, we developed a novel slurry containing a mixed oxidant of hydrogen peroxide (H2O2) and potassium ferrate (K2FeO4). The surface micro-morphology, profile, roughness, and damage layer characteristics of SCD were characterized by a 3D surface optical profiler, atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscope (TEM). Simultaneously, the reasons for the formation of high-quality surface of SCD were investigated. The results demonstrated that the polished SCD surface was smooth and scratch-free with an average Ra of 0.681 ± 0.023 nm over six areas of 868 × 868 μm2 and a damage layer thickness of 0.6 nm. Furthermore, the state of the chemical bonds of elements on the SCD surface was surveyed by X-ray photoelectron spectroscopy (XPS), and the polishing mechanism was deduced as follows: hydroxyl radicals were adsorbed on the SCD surface to oxidize and formed COH and CO bonds, while the damage due to lattice distortion resulted in the breakage of the CC bond to achieve carbon atom removal.

Enhancing H2O2 utilization efficiency for catalytic wet peroxide oxidation through the doping of La in the Fe-ZSM-5 Catalyst.

Iron-loaded zeolite (Fe-zeolite) has shown great potential as an efficient catalyst for degrading organic pollutants with high concentrations in the catalytic wet peroxide oxidation (CWPO) process under mild conditions. Here, 0.4 wt% Lanthanum (La) was added in the 1.0 wt% Fe-ZSM-5 by two-step impregnation method for an enhanced H2O2 utilization efficiency. For a systematical comparison, the CWPO process at 55 °C, where m-cresol with a high concentration of 1000 mg/L as a substrate, was studied over Fe-ZSM-5 and Fe-La-ZSM-5 catalysts. Compared with Fe-ZSM-5, Fe-La-ZSM-5 showed 15% higher H2O2 utilization efficiency with comparable total organic carbon (TOC) removal at around 40%, meanwhile with a 15% reduced metal leaching. Transmission electron microscopy (TEM) with elemental mapping (EDS), surface acidity analysis by Fourier transform infrared (FT-IR) and NH3-temperature programmed desorption (NH3-TPD), redox property analysis by Raman spectroscopy and H2-temperature-programmed reduction (H2-TPR) of both catalysts revealed, that the La doped Fe-ZSM-5 can provide an altered surface acidity, a more uniform and evenly dispersed surface Fe species with a promoted reducibility, which effectively promoted the accurate decomposition of H2O2 into the reactive •OH radicals, enhanced the H2O2 utilization efficiency, and increased the catalyst stability. Also, more than 90% conversion was maintained during the continuous experiment for more than 10 consecutive test days under 55 °C without pH adjustment, showing a promising possibility of the Fe-La-ZSM-5 for a practical wastewater treatment process.

Multivariate modelling analysis for prediction of glycidyl esters and 3-monochloropropane-1,2-diol (3-MCPD) formation in periodically heated palm oil

Palm oil is a vegetable oil that is widely used for cooking and deep-frying because of its affordability. However, repeatedly heated palm oil is also prone to oxidation due to its significant content of unsaturated fatty acids and other chemical toxicants such as glycidyl esters and 3-monochloropropane-1,2-diol (3-MCPD). Initially, the physicochemical properties such as colour, viscosity, peroxide, p-anisidine and total oxidation (TOTOX) of periodically heated palm oil were investigated. Chemical profiling and fingerprinting of six different brands of palm cooking oil during heating cycles between 90 and 360 min were conducted using Fourier transform infrared (FTIR) and 1H Nuclear Magnetic Resonance (NMR) metabolomics. In addition, the multivariate analysis was employed to evaluate the 1H NMR spectroscopic pattern of repeatedly heated palm oil with the corresponding physicochemical properties. The FTIR metabolomics showed significant different of the chemical fingerprinting subjected to heating duration, which in agreement with the result of 1H NMR metabolomics. Partial least squares (PLS) model revealed that most of the physicochemical properties of periodically heated palm oil are positively correlated (R2 values of 0.98–0.99) to their spectroscopic pattern. Based on the findings, the color of the oils darkened with increased heating time. The peroxide value (PV), p-anisidine value (p-AnV), and total oxidation (TOTOX) values increased significantly due to degradation of unsaturated compounds and oxidation products formed. We identified targeted metabolites (probable carcinogens) such as 3-monochloropropane-1,2-diol (3-MCPD) and glycidyl ester (GE), indicating the conversion of 3-MCPD to GE in repeatedly heated oils based on PCA and OPLSDA models. Our correlation analysis of NMR and physicochemical properties has shown that the conversion of 3-MCPD to GE was significantly increased from 180 to 360 min cooking time. The combination spectroscopic techniques with physicochemical properties are a reliable and robust methods to evaluate the characteristics, stability and chemical's structure changes of periodically heated palm oil, which may contribute to probable carcinogens development. This study has proven that combination of NMR and physicochemical analysis may predict the formation of the probable carcinogens of heated cooking oil over time which emphasizing the need to avoid certain heating cycles to mitigate formation of probable carcinogens during cooking process.

Thermal and environmental assessment of Botryococcus braunii green biodiesel with nanoparticles using energy-exergy-emission-sustainability (3ES) analysis in a diesel engine

To enhance the characteristics of biodiesel, the inclusion of nanoparticles has been used in recent years. The objective of present study is to analyse a clean, green, environmentally friendly, and sustainable third generation Botryococcus braunii microalgae biodiesel blended with three different nanoparticles, namely lanthanum oxide (La2O3), copper peroxide (CuO2), and cerium oxide (CeO2), in a volumetric quantity of 100 ppm for energy, exergy, and sustainability analysis in a diesel engine system, as well as the emission analysis to determine its impact on the climate. The work comprises a novel comparison based on first and second laws of thermodynamics. A low-displacement, four-stroke, single-cylinder, liquid-cooled, direct-injection engine running at 1500 rpm, 17.5 compression ratio, and injection timing of 23° crank angle bTDC is used for the study. The inclusion of various nanoparticles increases combustion pressure by 8.73–8.82 %, heat release rate by 18.69–24.47 %, NOx emissions by 3.68–30.80 %, energy efficiency by 5.99–7.38 %, exergy efficiency by 0.31–1.79 %, and sustainability by 0.62–0.91 %; however, PM emissions are reduced by 0.99–18.08 % and exergy destruction by 0.61–0.91 % at 100 % loading condition. Future studies will focus on reducing the NOx emissions and energy losses from the engine system.