Reactive oxygen species (ROS) generated by environmentally persistent free radicals (EPFRs) of 2-monochlorophenol, associated with CuO/silica particles, were detected using the chemical spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction electron paramagnetic resonance (EPR) spectroscopy. Yields hydroxyl radical ((•)OH), superoxide anion (O(2)(•-)), and hydrogen peroxide (H(2)O(2)) EPFR-particle systems reported. Failure to trap aqueous solvent, formed from reaction EPFRs...

Environmentally persistent free radicals, EPFRs, exist in significant concentration atmospheric particulate matter (PM). EPFRs are primarily emitted from combustion and thermal processing of organic materials, which the byproducts interact with transition metal-containing particles to form a radical-particle pollutant. While existence radicals has been known for over half-a-century, only recently that their presence environmental matrices health effects have started research, but still its...

Hydroxyl radicals were generated from an aqueous suspension of ambient PM2.5 and detected utilizing 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap coupled with electron paramagnetic resonance (EPR) spectroscopy. Results this study suggested the importance environmentally persistent free (EPFRs) in to generate significant levels ·OH without addition H2O2. Particles for which EPFRs allowed decay over time induced less hydroxyl radical. Additionally, higher particle concentrations...

Thermal degradation of lignin under two reaction regimes (pyrolysis in N(2) and oxidative pyrolysis 4% O(2) N(2)) has been investigated a tubular, isothermal, flow-reactor over the temperature range 200-900 °C at residence time 0.2 s. Two experimental protocols were adopted: (1) Partial which same sample was continuously pyrolyzed each (2) conventional pyrolysis, new samples temperature. The results identified common relationships between modes experiments, as well some differences. majority...

A chemical spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), in conjunction with electron paramagnetic resonance (EPR) spectroscopy was employed to measure the production of hydroxyl radical (·OH) aqueous suspensions 5% Cu(II)O/silica (3.9% Cu) particles containing environmentally persistent free radicals (EPFRs) 2-monochlorophenol (2-MCP). The results indicate: (1) a significant differences accumulated DMPO–OH adducts between EPFR and non-EPFR control samples, (2) strong correlation...

Environmentally persistent free radicals (EPFRs) are formed by the chemisorption of substituted aromatics on metal oxide surfaces in both combustion sources and superfund sites. The current study reports dependency EPFR yields their persistency loading particles (0.25, 0.5, 0.75, 1, 2, 5% CuO/silica). EPFRs were generated through exposure to three adsorbate vapors at 230 °C: phenol, 2-monochlorophenol (2-MCP), dichlorobenzene (DCBz). Adsorption resulted formation surface-bound phenoxyl-...

Abstract The effects of heat and UV exposure on the degradation free α‐tocopherol (oil form), dissolved in methanol, hexane were measured. Results showed that due to followed first order kinetics, with samples held at 180 °C showing greatest rate. Free degraded faster high temperatures than α‐tocopherol. In contrast, did not degrade when exposed light for as long 6 h, but methanol significantly a matter time. by 20 70%, respectively over this time span. A mechanism was proposed explain...

Additional experimental evidence is presented for in vitro generation of hydroxyl radicals because redox cycling environmentally persistent free (EPFRs) produced after adsorption 2-monochlorophenol at 230 °C (2-MCP-230) on copper oxide supported by silica, 5% Cu(II)O/silica (3.9% Cu). A chemical spin trapping agent, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), conjunction with electron paramagnetic resonance (EPR) spectroscopy was employed. Experiments spiked O(17) water have shown that ∼15%...

The formation of radicals from the gas-phase pyrolysis hydroquinone, catechol, and phenol over a temperature range 400−750 °C was studied using technique low-temperature matrix isolation electron paramagnetic resonance (LTMI EPR). Cooling reactor effluent in nitrogen carrier gas to 77 K produces cryogenic that exhibits poorly resolved EPR spectra. However, carbon dioxide as formed that, upon annealing by slowly raising followed rapid recooling K, yielded more resolved, identifiable Annealed...

The goal of the study was to synthesize a surfactant made α-tocopherol (vitamin E) and ascorbic acid C) antioxidant properties dubbed as EC, use this make poly(lactic-co-glycolic) (PLGA) nanoparticles. Self-assembled EC nanostructures PLGA-EC nanoparticles were by nanoprecipitation, their physical (size, size distribution, morphology) studied at different salt concentrations, polymer/surfactant ratios. shown form self-assembled in water with 22 138 nm presence sodium chloride, or 12 31 when...

In the current study, electron paramagnetic resonance (EPR) spectroscopy was employed to measure environmentally persistent free radicals (EPFRs) in total particulate matter (TPM) of mainstream and sidestream TPM conventional cigarettes e-cigarettes. Comparable concentrations EPFRs were detected both (8.05 ± 1.32) × 104 pmol/g (7.41 0.85) cigarettes. exposure air resulted long-lived oxygen centered, secondary with EPR g values 2.0041 for 2.0044 sidestream. Surprisingly, despite no combustion...

The formation of radicals from the gas-phase pyrolysis phenol over a temperature range 400-1000 degrees C was studied using technique low matrix isolation electron paramagnetic resonance (LTMI EPR). Cooling reactor effluent in CO2 carrier gas to 77 K produces cryogenic that exhibits complex EPR spectra. However, annealing by slowly raising yielded well-resolved, identifiable All annealed spectra 700-1000 resulted generation with six lines, hyperfine splitting constant approximately 6.0 G, g...

Gasification is an effective technology for the thermal disposal of municipal solid waste (MSW) with lower dioxin emission compared to prevailing incineration process. Nevertheless, mechanism formation in reducing atmosphere during gasification process was seldomly explored. Herein, effects atmosphere, temperature, and chlorine source were systematically investigated terms distribution. With CO2 H2O as agents, a reaction formed abundant H2 which effectively suppressed generation C-Cl,...

The fractional pyrolysis of lignin model compound para-coumaryl alcohol (p-CMA) containing a propanoid side chain and phenolic OH group was studied using the System for Thermal Diagnostic Studies at temperatures from 200 to 900 °C, in order gain mechanistic insight into role large substituents high-lignin feedstocks pyrolysis. Phenol its simple derivatives p-cresol, ethyl-, propenyl-, propyl-phenols were found be major products predominantly formed low (<500 °C). A cryogenic trapping...

This work reports on a mechanistic study of environmentally persistent free radicals (EPFRs) formation in soils using polymer-modified and copper-loaded montmorillonite clays as model soil surrogates, utilizing phenol precursor pollutant.

Environmentally persistent free radicals (EPFRs) are combustion products present in substantial numbers on atmospheric particulate matter with half-lives of days to years. The mechanisms linking EPFR exposure and respiratory diseases unclear, but likely involve oxidative stress. We investigated the by which impact well-differentiated primary human nasal epithelial cells from subjects sensitive or resistant oxidant stressors, cultured at an air-liquid interface. found that induced...

The gas phase delivery of lignin into the hot zone cw-CO2 laser powered homogeneous pyrolysis (LPHP) reactor under &amp;ldquo;wall-less&amp;rdquo; conditions led to break down macromolecules neutral oligomers and paramagnetic fragments deposited onto cell walls. Formation PAHs was observed during defragmentation accelerated with increased power. Remarkably, no phenolic compounds were detected among - intermediate radicals oligomers. It is concluded that PAH soot-like conjugated particulates...

The primary depolymerization processes of hydrolytic lignin (HL) are examined, focusing on the formation intermediate oligomers and bulky environmentally persistent free radicals (EPFRs). Fragmentation HL was conducted in a continuous atomization (CA) fast flow reactor, where HL, dissolved 9:1 acetone-to-water solution, dispersed. Results indicated that fragmentation occurs significantly faster gas phase comparison to literature rate major biofuel-phenolic compounds. In other words, phenolic...

The gas-phase delivery of lignin into the hot zone cw-CO2 laser-powered homogeneous pyrolysis (LPHP) reactor under “wall-less” conditions led to breakdown macromolecules neutral oligomers and paramagnetic fragments deposited onto cell walls. formation PAHs was observed during defragmentation lignin, accelerated with increased laser power. Remarkably, no phenolic compounds were detected among fragments—intermediate radicals oligomers. It is concluded that PAH soot-like conjugated particulates...