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Molecules (Basel, Switzerland) Feb 2020The development of sustainable processes and products through innovative catalytic materials and procedures that allow a better use of resources is undoubtedly one of... (Review)
Review
The development of sustainable processes and products through innovative catalytic materials and procedures that allow a better use of resources is undoubtedly one of the most significant issues facing researchers nowadays. Environmental and economically advanced catalytic processes for selective oxidation of alcohols are currently focused on designing new catalysts able to activate green oxidants (dioxygen or peroxides) and applying unconventional conditions of sustainable significance, like the use of microwave irradiation as an alternative energy source. This short review aims to provide an overview of the recently (2015-2020) discovered homogeneous aerobic and peroxidative oxidations of primary and secondary alcohols catalyzed by copper complexes, highlighting new catalysts with potential application in sustainable organic synthesis, with significance in academia and industry.
Topics: Alcohols; Catalysis; Copper; Green Chemistry Technology; Humans; Microwaves; Molecular Structure; Oxidants; Oxidation-Reduction; Oxygen; Peroxides
PubMed: 32050493
DOI: 10.3390/molecules25030748 -
Journal of Hazardous Materials Jul 2022Field-weathered crude oil-containing soils have a residual concentration of hydrocarbons with complex chemical structure, low solubility, and high viscosity, often...
Field-weathered crude oil-containing soils have a residual concentration of hydrocarbons with complex chemical structure, low solubility, and high viscosity, often poorly amenable to microbial degradation. Hydrogen peroxide (HO)-based oxidation can generate oxygenated compounds that are smaller and/or more soluble and thus increase petroleum hydrocarbon biodegradability. In this study, we assessed the efficacy of HO-based oxidation under unsaturated soil conditions to promote biodegradation in a field-contaminated and weathered soil containing high concentrations of total petroleum hydrocarbons (25200 mg TPH kg) and total organic carbon (80900 mg TOC kg). Microcosms amended with three doses of 48 g HO kg soil (unactivated or Fe-activated) or 24 g sodium percarbonate kg soil and nutrients did not show substantial TPH changes during the experiment. However, 7.6-41.8% of the TOC concentration was removed. Furthermore, production of DOC was enhanced and highest in the microcosms with oxidants, with approximately 20-40-fold DOC increase by the end of incubation. In the absence of oxidants, biostimulation led to > 50% TPH removal in 42 days. Oxidants limited TPH biodegradation by diminishing the viable concentration of microorganisms, altering the composition of the soil microbial communities, and/or creating inhibitory conditions in soil. Study's findings underscore the importance of soil characteristics and petroleum hydrocarbon properties and inform on potential limitations of combined HO oxidation and biodegradation in weathered soils.
Topics: Biodegradation, Environmental; Hydrocarbons; Hydrogen Peroxide; Oxidants; Peroxides; Petroleum; Soil; Soil Microbiology; Soil Pollutants
PubMed: 35364529
DOI: 10.1016/j.jhazmat.2022.128770 -
The Analyst Jul 2022The illegal addition of melamine to dairy products and the contamination of water with mercury (Hg) are serious threats to human health. Hence, herein, a highly...
Highly efficient peroxidase-like activity of a metal-oxide-incorporated CeO-MIL(Fe) metal-organic framework and its application in the colorimetric detection of melamine and mercury ions induced hydrogen and covalent bonds.
The illegal addition of melamine to dairy products and the contamination of water with mercury (Hg) are serious threats to human health. Hence, herein, a highly sensitive colorimetric sensor for the visual detection of melamine and Hg ions has been developed using a metal-oxide-in-MOF nanomaterial (CeO-MIL (Fe)) as a peroxidase mimic. Highly mono-dispersed CeO-MIL (Fe) was synthesised a facile hydrothermal process. The CeO-MIL (Fe) exhibited outstanding peroxidase activity, and can catalyze the oxidation of TMB (3,3',5,5'-tetramethylbenzidine) by HO, resulting in the development of blue-coloured oxidation products within 5 min. In the presence of melamine, the HO interacts with melamine to form melamine-HO H-bonding. Due to the uptake of HO by melamine, the catalytic oxidation reaction was halted, and the blue TMB oxidation product became pale. The relative change in the absorption intensity at 652 nm was proportional to the concentration of melamine in the linear range of 0-0.1 μM and the detection limit was found to be 8 nM. Subsequently, when Hg ions were added to the above solution, the Hg ions reacted with melamine strong covalent bonding to form a Hg-melamine covalent complex, causing the release of HO, which again strongly oxidised the TMB to give the blue-coloured oxidation product. Furthermore, the comparative change in the absorption intensity at 652 nm was dependent on the concentration of Hg ions in the linear range of 0-6 nM, and a detection limit of 2 nM was achieved. The suggested system has several advantages including greater simplicity, good selectivity, naked-eye detection and cost-effectiveness without using any complicated detection procedure. This technique was successfully utilized to identify melamine in real foods and Hg ions in real water samples, yielding high recovery rates.
Topics: Humans; Colorimetry; Hydrogen; Hydrogen Peroxide; Mercury; Metal-Organic Frameworks; Oxides; Peroxidases; Triazines; Water
PubMed: 35766241
DOI: 10.1039/d2an00864e -
Environmental Science & Technology Feb 2023Byproduct formation (chlorate, bromate, organic halogen, etc.) during sulfate radical (SO)-based processes like ultraviolet/peroxymonosulfate (UV/PMS) has aroused...
Overlooked Cytotoxicity and Genotoxicity to Mammalian Cells Caused by the Oxidant Peroxymonosulfate during Wastewater Treatment Compared with the Sulfate Radical-Based Ultraviolet/Peroxymonosulfate Process.
Byproduct formation (chlorate, bromate, organic halogen, etc.) during sulfate radical (SO)-based processes like ultraviolet/peroxymonosulfate (UV/PMS) has aroused widespread concern. However, hypohalous acid (HOCl and HOBr) can form via two-electron transfer directly from PMS, thus leading to the formation of organic halogenated byproducts as well. This study found both PMS alone and UV/PMS can increase the toxicity to mammalian cells of wastewater, while the UV/HO decreased the toxicity. Cytotoxicity of two wastewater samples increased from 5.6-8.3 to 15.7-29.9 mg-phenol/L, and genotoxicity increased from 2.8-3.1 to 5.8-12.8 μg 4-NQO/L after PMS treatment because of organic halogen formation. Organic halogen formation from bromide rather than chloride was found to dominate the toxicity increase. The SO-based process UV/PMS led to the formation of both organic halogen and inorganic bromate and chlorate. However, because of the very low concentration (<20 μg/L) and relatively low toxicity of bromate and chlorate, contributions of inorganic byproducts to toxicity increase were negligible. PMS would not form chlorate and bromate, but it generated a higher concentration of total organic halogen, thus leading to a more toxic treated wastewater than UV/PMS. UV/PMS formed less organic halogen and toxicity because of the destruction of byproducts by UV irradiation and the removal of byproduct precursors. Currently, many studies focused on the byproducts bromate and chlorate during SO-based oxidation processes. This work revealed that the oxidant PMS even needs more attention because it caused higher toxicity due to more organic halogen formation.
Topics: Animals; Oxidants; Hydrogen Peroxide; Bromates; Wastewater; Chlorates; Water Pollutants, Chemical; Peroxides; Oxidation-Reduction; Halogens; Water Purification; Mammals
PubMed: 36787277
DOI: 10.1021/acs.est.2c06965 -
Chemosphere Dec 2023This study aims to explore the reusability of wastewater treatment by-product for photo-Fenton process to treat an organic pollutant model. The optimal condition,...
This study aims to explore the reusability of wastewater treatment by-product for photo-Fenton process to treat an organic pollutant model. The optimal condition, reactive oxygen species (ROS), and kinetic approach in photo-Fenton process was discussed. The Metal oxide crystal pellets from are a by-product of the Fluidized-Bed Crystallization (FBC) process and can be used as a catalyst in the Photo-Fenton process. Electroplating wastewater containing iron and copper was treated via the FBC process using granulated Al(OH) as carrier seeds. The binary oxide of FeOOH and CuO on the Al(OH) surface (FeCu@Al(OH)) was identified as the FBC by-product after characterization using FTIR and XPS analysis. In the photo-Fenton process, visible light from a fluorescence lamp with a wavelength of 400-610 nm was chosen as an irradiation source. Oxalic acid was added as chelating agent to form photosensitive iron oxalate species and hydrogen peroxide was applied as oxidant to generate active radical to decolorize and mineralize RB5 synthesized solution (100 mg/L). The operating conditions including the oxalic acid to pollutant ratio ([OA]/[RB5]) of 4.5-13.0, reaction pH (pHr) of 3-7 and initial to theoretical hydrogen peroxide molar ratio [HO]/[ HO] of 35%-120% were optimized. Under the optimal conditions, pH = 5.0; [HO]/[RB5] at 75% stoichiometric and [OA]/[RB5] = 9, the RB5 is almost completely decolorized after 210 min of operation and the mineralization efficiency is 58%. The contribution of •OH, O, and O to the Photo-Fenton system was determined using ESR analysis with the addition of DMPO and TEMP as spin trap agents. The kinetic analysis reveals the observed rate constants k, k and k from fitting are 0.0120, 0.0054 and 0.0001 Ms, respectively.
Topics: Hydrogen Peroxide; Copper; Azo Compounds; Kinetics; Light; Oxides; Environmental Pollutants; Oxalic Acid; Oxidation-Reduction
PubMed: 37758073
DOI: 10.1016/j.chemosphere.2023.140268 -
Environmental Science & Technology May 2022Rapid generation of high-valent cobalt-oxo species (Co(IV)═O) for the removal of organic contaminants has been challenging because of the low conversion efficiency of...
Rapid generation of high-valent cobalt-oxo species (Co(IV)═O) for the removal of organic contaminants has been challenging because of the low conversion efficiency of Co(III)/Co(II) and the high activation energy barrier of the Co(II)-oxidant complex. Herein, we introduced nitrogen (N) vacancies into graphite carbon nitride imbedded with cobalt carbonate (CCH/CN-V) in a peroxymonosulfate (PMS)/visible light system to break the limitations of a conventional two-electron transfer path. These N vacancies enhanced the electron distribution of the Co 3d orbital and lowered the energy barrier to cleave the O-O bond of PMS in the Co(II)-PMS complex, achieving the modulation of major active species from O to Co(IV)═O. The developed synergistic system that exhibited adsorption and oxidation showed remarkable selectivity and contaminant removal performance in inorganic (Cl, NO, HCO, and HPO) organic (HA) and even practical aqueous matrices (tap water and secondary effluent). This study provides a novel mechanistic perspective to modulate the nonradical path for refractory contaminant treatment via defect engineering.
Topics: Cobalt; Nitrogen; Oxidants; Peroxides
PubMed: 35442647
DOI: 10.1021/acs.est.2c01913 -
The Journal of Organic Chemistry Jul 2022A total of 16 oxidizing reagents were screened to compare their oxidation selectivities for axial and equatorial hydroxyl moieties using steroidal methyl...
A total of 16 oxidizing reagents were screened to compare their oxidation selectivities for axial and equatorial hydroxyl moieties using steroidal methyl chenodeoxycholate, methyl deoxycholate, and 4--butylcyclohexanol (/ 1:1 mixture). These compounds were selected for their stable chair conformations. The results of our study demonstrated that, for the oxidation of a scaffold bearing both axial and equatorial hydroxyl groups, nitroxide-radical-based reagents should be the first choice if oxidation of the equatorial hydroxyl group is needed and Stevens or Dess-Martin reagents should be the first choice for the preferential oxidation of the axial hydroxyl group.
Topics: Hydroxyl Radical; Molecular Conformation; Oxidants; Oxidation-Reduction
PubMed: 35775929
DOI: 10.1021/acs.joc.2c00877 -
Chemosphere Dec 2015Microbial fuel cells (MFCs) have gained tremendous global interest over the last decades as a device that uses bacteria to oxidize organic and inorganic matters in the... (Review)
Review
Microbial fuel cells (MFCs) have gained tremendous global interest over the last decades as a device that uses bacteria to oxidize organic and inorganic matters in the anode with bioelectricity generation and even for purpose of bioremediation. However, this prospective technology has not yet been carried out in field in particular because of its low power yields and target compounds removal which can be largely influenced by electron acceptors contributing to overcome the potential losses existing on the cathode. This mini review summarizes various electron acceptors used in recent years in the categories of inorganic and organic compounds, identifies their merits and drawbacks, and compares their influences on performance of MFCs, as well as briefly discusses possible future research directions particularly from cathode aspect.
Topics: Bacteria; Bioelectric Energy Sources; Electrodes; Electrons; Oxidants; Oxidation-Reduction; Prospective Studies; Waste Disposal, Fluid; Wastewater
PubMed: 25907762
DOI: 10.1016/j.chemosphere.2015.03.059 -
Journal of Environmental Science and... 2022This study aimed to evaluate an alternative to reduce trihalomethane (THM) formation in brewing water. THM affects the organoleptic properties of water and,...
This study aimed to evaluate an alternative to reduce trihalomethane (THM) formation in brewing water. THM affects the organoleptic properties of water and, consequently, the produced beer. Water treatment based on common chemicals such as alum and free chlorine could potentially form THM. Therefore, we studied the replacement of chemicals used in water treatment: aluminum sulfate by a tannin-based coagulant and sodium hypochlorite by chlorine dioxide. Experimentally, jar tests were conducted, and the role of coagulants and oxidizing agents was evaluated for: the removal of apparent color, turbidity, natural organic matter (NOM) and microorganisms; the formation of trihalomethanes (THM); and the sensory quality of the water. Using tannin-based coagulant with chlorine dioxide was associated with the lowest THM in treated water (1.7 µg/L) and higher satisfaction in the sensory analysis. However, using these chemicals make the water treatment more expensive than the current strategy. Overall, using the tannin-based coagulant and chlorine dioxide treatment is an alternative to produce water with a lower THM concentration, better physical-chemical, and sensory quality. These findings motivate further brewing experiments and a deeper economics evaluation considering the process's sustainability.
Topics: Trihalomethanes; Chlorine; Tannins; Sodium Hypochlorite; Disinfection; Water Purification; Oxidants; Water Pollutants, Chemical
PubMed: 36111665
DOI: 10.1080/10934529.2022.2123186 -
Molecules (Basel, Switzerland) May 2017A suitable oxidative system is crucial to electrophilic selenium catalysis (ESC). This short review offers the overview of recent development in ESC with electrophilic... (Review)
Review
A suitable oxidative system is crucial to electrophilic selenium catalysis (ESC). This short review offers the overview of recent development in ESC with electrophilic N-F reagents as the oxidants. Several highly selective transformations of alkenes such as allylic or vinylic imidation, pyridination, -dichlorination, oxidative cyclization and asymmetric cyclization have been described.
Topics: Alkenes; Benzofurans; Catalysis; Cyclization; Imidoesters; Indoles; Molecular Structure; Organoselenium Compounds; Oxidants; Oxidation-Reduction; Pyridines; Stereoisomerism; Sulfonamides
PubMed: 28534837
DOI: 10.3390/molecules22050835