Redox processes are at the heart of synthetic methods that rely on either electrochemistry or photoredox catalysis, but how do electrochemistry and photoredox catalysis compare? Both approaches provide access to high energy intermediates (e.g., radicals) that enable bond formations not constrained by the rules of ionic or 2 electron (e) mechanisms. Instead, they enable 1e mechanisms capable of bypassing electronic or steric limitations and protecting group requirements, thus enabling synthetic chemists to disconnect molecules in new and different ways. However, while providing access to similar intermediates, electrochemistry and photoredox catalysis differ in several physical chemistry principles. Understanding those differences can be key to designing new transformations and forging new bond disconnections. This review aims to highlight these differences and similarities between electrochemistry and photoredox catalysis by comparing their underlying physical chemistry principles and describing their impact on electrochemical and photochemical methods.

Photons or Electrons? A Critical Comparison of Electrochemistry and Photoredox Catalysis for Organic Synthesis.

The present research work was intended to find out the useful
information on identification, separation and photocatalytic
degradation of organic compounds present in leather industry
wastewater. The separation of organic compounds present in leather
industry wastewater was carried out by solvent extraction. The
separated crude extracted products were purified through column
chromatography and characterized by UV–vis spectrophotometer, gas
chromatography–mass spectrophotometer, liquid
chromatography–mass spectrophotometer, 1H and 13C
Fourier-transform nuclear magnetic resonance spectroscopy. The
elemental analysis of wastewater and solid residue was carried out by
inductively coupled plasma-optical emission and X-ray fluorescence
spectroscopy. The organic compounds such as nonadec-1-ene,
2-phenylethanol, 2,4-di-tert-butylphenol and other organic compounds in
the leather industry wastewater were identified. Out of these organic
compounds, 2-phenylethanol was photocatalytically degraded using
standard Degussa P-25 TiO2 (100 mg) photocatalyst under the irradiation
of UV light. Result has been shown that 2-phenylethanol was transformed
into 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-methylphenol
then the prolonged time (30 h) irradiation leads to 100 % degradation
of 2-phenylethanol. Further possible degradation mechanism of
2-phenylethanol was proposed based on the electrospray ionization mass
spectrometry analysis of degraded samples. The degradation of
2-phenylethanol was confirmed by chemical oxygen demand analysis of
degraded samples. The physicochemical parameters such as pH, color,
chemical oxygen demand, total dissolved solids, electrical conductivity
and ionic chromatography analysis of the leather industry wastewater
were also measured.

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Study on identiﬁcation of leather industry wastewaterconstituents and its photocatalytic treatment

Flow Behaviors of Shale Oil in Kerogen Slit by Molecular Dynamics Simulation

Abstract. Wetlands provide quintessential ecosystem services such as maintenance of water quality, water supply and biodiversity, among others; however, wetlands are also among the most threatened ecosystems worldwide. Natural dissolved organic matter (DOM) is an abundant and critical component in wetland biogeochemistry. This study describes the first detailed, comparative, molecular characterization of DOM in subtropical, pulsed, wetlands, namely the Everglades (USA), the Pantanal (Brazil) and the Okavango Delta (Botswana), using optical properties, high-field nuclear magnetic resonance (NMR) and ultrahigh-resolution mass spectrometry (FT-ICRMS), and compares compositional features to variations in organic matter sources and flooding characteristics (i.e., differences in hydroperiod). While optical properties showed a high degree of variability within and between the three wetlands, analogies in DOM fluorescence properties were such that an established excitation emission matrix fluorescence parallel factor analysis (EEM-PARAFAC) model for the Everglades was perfectly applicable to the other two wetlands. Area-normalized 1H NMR spectra of selected samples revealed clear distinctions of samples while a pronounced congruence within the three pairs of wetland DOM readily suggested the presence of an individual wetland-specific molecular signature. Within sample pairs (long- vs. short-hydroperiod sites), internal differences mainly referred to intensity variations (denoting variable abundance) rather than to alterations of NMR resonances positioning (denoting diversity of molecules). The relative disparity was largest between the Everglades long- and short-hydroperiod samples, whereas Pantanal and Okavango samples were more alike among themselves. Otherwise, molecular divergence was most obvious in the case of unsaturated protons (δH > 5 ppm). 2-D NMR spectroscopy for a particular sample revealed a large richness of aliphatic and unsaturated substructures, likely derived from microbial sources such as periphyton in the Everglades. In contrast, the chemical diversity of aromatic wetland DOM likely originates from a combination of higher plant sources, progressive microbial and photochemical oxidation, and contributions from combustion-derived products (e.g., black carbon). FT-ICRMS spectra of both Okavango and Pantanal showed near 57 ± 2 % CHO, 8 ± 2 % CHOS, 33 ± 2 % CHNO and

Molecular Characterization of Dissolved Organic Matter from Subtropical Wetlands: A Comparative Study Through the Analysis of Optical Properties, NMR and FTICR/MS

Aluminum is a nonessential metal to which humans are frequently exposed. Aluminum in the food supply comes from natural sources, water used in food preparation, food ingredients, and utensils used during food preparations. The amount of aluminum in the diet is small, compared with the amount of aluminum in antacids and some buffered analgesics. The healthy human body has effective barriers (skin, lungs, gastrointestinal tract) to reduce the systemic absorption of aluminum ingested from water, foods, drugs, and air. The small amount of aluminum (<1%) that is systemically absorbed is excreted principally in the urine and, to a lesser extent, in the feces. No reports of dietary aluminum toxicity to healthy individuals exist in the literature. Aluminum can be neurotoxic, when injected directly into the brains of animals and when accidentally introduced into human brains (by dialysis or shrapnel). A study from Canada reports cognitive and other neurological deficits among groups of workers occupationally exposed to dust containing high levels of aluminum. While the precise pathogenic role of aluminum in Alzheimer's disease (AD) remains to be defined, present data do not support a causative role for aluminum in AD. High intake of aluminum from antacid for gastrointestinal ailments has not been reported to cause any adverse effects and has not been correlated with neurotoxicity or AD. Foods and food ingredients are generally the major dietary sources of aluminum in the United States. Cooking in aluminum utensils often results in statistically significant, but relatively small, increases in aluminum content of food. Common aluminum-containing food ingredients are used mainly as preservatives, coloring agents, leavening agents, anticaking agents, etc. Safety evaluation and approval of these ingredients by the Food and Drug Administration indicate that these aluminum-containing compounds are safe for use in foods.

Safty evaluation of dietary aluminum

NMR spectroscopy of wastewater: A review, case study, and future potential.

Towards real-time kinetic monitoring of wastewater treatment: A case study of sunlight and ozone treatment of unconcentrated wastewater using flow NMR

Sulfur based solid-state Na+ conductors exhibit high ionic conductivity and are promising candidates for electrolytes used in the next generation all-solid-state sodium-ion batteries. Sodium thioantimonate (Na3SbS4), for example, shows an ionic conductivity of 1 mS/cm, comparable to its liquid counterparts. In contrast to the well-known thiophosphate solid-state electrolytes, Na3SbS4 is chemically stable in dry air. However, solid-state Na-ion batteries assembled using Na3SbS4 as the electrolyte show a decaying performance over the charge and discharge cycles. This work characterized the molecular processes occurring at the interface between Na3SbS4 solid electrolyte and the anode. This interfacial chemistry was probed in real-time (in-situ) using Raman spectroscopy while the battery was in operation. Combined with the characterization results obtained from X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), we observed a largely irreversible decomposition of SbS4
 3- while Na3SbS4 was directly exposed to negative potentials (vs. Na/Na+). Sb2S3 and elemental Sb are the two major decomposition byproducts formed and accumulated at the Na3SbS4/anode interface. This result unravels the decomposition mechanism at the Na3SbS4/anode interface in all-solid sodium batteries. It provides deep molecular insights into designing ideal protective layers at this critical interface.

Xiang You

Papers

NMR spectroscopy of wastewater: A review, case study, and future potential.

Towards real-time kinetic monitoring of wastewater treatment: A case study of sunlight and ozone treatment of unconcentrated wastewater using flow NMR

In-Situ Characterization of Molecular Processes at the Anode/Na3SbS4 Electrolyte Interface in All-Solid-State Sodium Batteries