Papers by Keyword: Hydrogen Peroxide

Abstract: The incorporation of quasi-atomic Ni (OH)₂ clusters onto graphitic C₃N₄ (gCN) remarkably enhances the photocatalytic production of hydrogen peroxide (H₂O₂) and benzaldehyde (BAL) from benzyl alcohol (BA) in water under visible light at 440 nm. Upon loading Ni (OH)₂, H₂O₂ production reaches 306 µmol g⁻¹ h⁻¹ and BAL production reaches 270 µmol L⁻¹ h⁻¹. The high photocatalytic performance is attributed to the formation of ultrasmall clusters of Ni (OH)₂, which reduce recombination by trapping holes, thereby increasing the activity (BA conversion). Efficient hole transfer to BA is also facilitated, enhancing selectivity (BAL selectivity). Upon the addition of Ni (OH)₂, the steady-state electron population photoexcited by visible light increases 5.5-fold. The proposed modification of gCN with Ni achieves nearly 100% efficiency in both activity and selectivity to produce H₂O₂, while also generating BAL, a value-added product. This demonstrates its potential for sustainable chemical transformations using visible light and water as a green solvent.

Abstract: Oil palm empty fruit bunch (OPEFB) is one of the waste by-products when palm oil is produced. Although a waste product, it can be turned into a valuable product by extracting nanocellulose through acid hydrolysis. The process requires a few steps; the most important is the pre-treatment process. In this research, bleaching pretreatment was used to characterize empty oil palm fruit bunches as raw materials for hydrolysis reactions to extract nanocellulose. The bleaching process was done using H₂O₂ and the resulting samples were characterized using FT-IR and SEM. FT-IR analysis revealed that lignin-associated carbonyl groups were removed and there was a decrease in hemicellulose-related acetyl group peaks which confirmed effective pre-treatment. According to Scanning Electron Microscopy (SEM), surface morphology has also changed where the bleached fibres exhibited a rougher surface than the ones that were not bleached. Bleaching is proven to be successful at removing surface impurities, hemicellulose, and lignin and isolating the cellulose for the acid hydrolysis process.

Abstract: Reducing the pressing temperature of plywood on the FF binder allows you to reduce its cost, but at the same time, the physical and mechanical characteristics of plywood deteriorate. Modification of the phenol-formaldehyde binder with hydrogen peroxide reduces the curing time of the phenolic binder, the pressing temperature of the FSF plywood, and improves the physical and mechanical properties of the FSF plywood. Regression models have been developed for dependence of the plywood strength during cleavage along the adhesive seam, strength during static bending, and thickness swelling after 24 hours in water on the factors varied in the experiment – the proportion of hydrogen peroxide addition and the pressing temperature. The IR spectra of plywood allow us to estimate the effect of H₂O₂ on the bonds involved in the structure formation of material. With the addition of hydrogen peroxide, the number of active methylene groups decreases, which indicates an increase in degree curing of modified binder.

Abstract: The current pandemic brought to our attention the need for continuous research and development on the fight against pathogens. The use of derivatives of starch nanocrystals (SNC) with antimicrobial activities offers a good alternative to conventional antimicrobial agents since they can be sourced from readily available, biodegradable, and biocompatible raw materials. In this study, starch nanocrystals were prepared by acid hydrolysis and oxidized using hydrogen peroxide. The resulting oxidized starch nanocrystals showed inhibitory effect against E. coli. FTIR analysis showed that the antimicrobial activity could be due to the introduction of carbonyl groups in the starch chain. Due to the versatility of starch nanocrystals, other derivatives with improved antimicrobial activity or other tailored properties could also be developed.

Abstract: It's still a challenge to detect cholesterol more rapidly and easily. As a result, using a colorimetric sensor to detect cholesterol may result in the development of a ready-to-use. This research shows how a TiO₂ nanoparticles may be utilized as a peroxidase mimic to detect H₂O₂ and free cholesterol. The TiO₂ Nanoparticles was carefully studied in terms of structural, morphological, and functional characteristics. In the existence of cholesterol oxidase, and the proposed approach comprises detecting H₂O₂ produced during cholesterol oxidation. The TiO₂ nanoparticles sensor has shown good cholesterol detection sensitivity with a LOD as low as 0.061 M and a linear response in the 0.1 mM to 50 mM range.

Abstract: The ecological situation in the world requires the solution of environmental problems associated with the processes of wastewater treatment, hydrogen sulfide pollution of various industrial facilities in order to remove such harmful impurities. The unpleasant odor that appears in industrial and adjacent waste processing areas is a constant concern for the protection of the environment. To solve these problems, it is advisable to use selective sorbents - complex. The introduction of metal ions into complex fibers due to the formation of a coordinated bond between the groups of the metal and the polymer ligand gives high molecular weight complex compounds. The operational and selective properties of the materials based on high-molecular-weight complex compounds can be determined by the type of metal ion introduced into macromolecules, the nature of the polymer chain, and thermodynamic stability. By changing the action of the above factors, complexites can be synthesized for use as highly selective catalysts for various chemical processes. The paper presents data on the catalytic activity of fibers with Cu²⁺, Co²⁺, Ni²⁺ ions with complexing fibers containing carboxyl, amidoxime, hydroxamic groups, using the example of the decomposition of hydrogen peroxide and oxidation of H₂S, Na₂S. An inhibitory effect on the oxidation of fiber functional groups in the pH range 5.5 - 12.5 was revealed. The operational and selective properties of materials based on complexites can be determined by the type of metal ion introduced into the macromolecules, by the nature of the polymer chain. By changing the action of the above factors, complexites can be synthesized to be used as highly selective catalysts for various chemical processes. It was found that the catalytic activity of the complex depends on pH, the stereochemistry of the coordination centers in the fiber matrix and significantly exceeds the activity of model low-molecular-weight complex compounds.

Abstract: The paper presents studies of the process of purification of model wastewater, which contained high concentrations of animal proteins, fats and hydrocarbons. The model wastewater solution was treated by biosorption treatment in a bioreactor; with pre-ozonation (O₃) and biosorption purification in the bioreactor and in the variant with pre-treatment with ozonation and hydrogen peroxide – by the method of AOPs (O₃/H₂O₂) or the process «Peroxon». The efficiency of cleaning by chemical oxygen consumption when using the AOPs method reached (97-98) %, disinfection – up to 100 %.

Abstract: Hydrogen peroxide (H₂O₂) is a significant signal molecule in physiological and pathological processes. Levels of H₂O₂ in bacteria are proved to be a key factor in immune response. To sum up, detection of H₂O₂ levels in living bacteria is remarkable for further study of its physiological and pathological effects. Herein, we propose a novel ratiometric fluorescent probe (Nahp) to detect H₂O₂ in living cells and bacteria. In addition, based on boronate, Nahp has satisfactory selectivity and sensitivity toward H₂O₂ (LOD = 0.158 μM). Furthermore, with excellent detection performance to H₂O₂, Nahp is successfully used for fluorescent bioimaging of H₂O₂ and measuring H₂O₂ accumulation in bacteria. Most importantly, the probe was also used to image H₂O₂ in three Gram-negative bacteria, clearly revealing for the first time significant differences in H₂O₂ expression levels in live bacteria.

Abstract: Portable electrochemical sensors based on noble metal nanoparticles (МеNPs) for the quantitative determination of hydrogen peroxide (H₂O₂) and sulfur-containing amino acids (cysteine, methionine, glutathione) are discussed. These sensors have high sensitivity (pM), with low sample requirements (<50 μl). This article discusses methods for producing sensors based on silver and gold nanoparticles and their application in voltammetry. It is shown that the sensitivity of H₂O₂ determination on a sensor based on silver nanoparticles (AgNPs) depends on their size. Their size is determined by the reducing agent. Sensors based on AgNPs of spherical shape with the smallest size from 0.5 to 17.5 nm have the highest sensitivity for determining H₂O₂, but a narrow range of determined concentrations. Sensors on medium-sized AgNPs have optimal metrological characteristics. Their size is from 10 to 55 nm, less sensitive, but with a wide range of determined concentrations from 0.1 to 1 nm H₂O₂. The linearity of the range of glutathione concentrations is 1.0-10.0 pM. The linearity of the range of determined concentrations of methionine is 1–26 рМ.

Abstract: The use of hydrogen peroxide and hydrazine sulfate for the treatment of chrome-containing rinsing waters of galvanic production of machine-building enterprises is proposed. The process of reducing chromium (6+) to (3+) from rinsing waters with a concentration of 8.55 mg/dm³ was studied. These reagents allow reducing more than 99% of chromium (6+) to chromium (3+) and maintaining a low salt content of treated wastewater. The consumption of hydrogen peroxide is 1.5 mg/dm³, and the consumption of hydrazine sulfate is 10 mg/dm³. The current situation in the treatment of galvanic wastewater leads to pollution of the environment with dangerous substances (CN^-, Cr⁶⁺, F^-, Cd²⁺), irrational use of raw materials and significant economic losses. The possibility of extracting valuable components from wastewater, in order to recycle them and return the treated water to production, is considered. Hydrogen peroxide is effective for treating acidic wastewater, and hydrazine sulfate can be used for both acidic and alkaline wastewater. Removal of excess hydrogen peroxide from the solution after reduction of chromium (6+) before precipitation of chromium (3+) hydroxide is required. The toxicity of hydrazine compounds must be taken into account.