Characterization of the Degradation and Nitrogenous Disinfection Byproduct Formation of Nitrogen-Containing Benzoheterocyclic Compounds during the UV-LED (275 nm)/Chlorine Process: Roles of Reactive Species and Pathway of Dichloroacetonitrile Formation.

Nitrogen-containing benzoheterocyclic compounds (NBHCs) are important precursors of nitrogenous disinfection byproducts (N-DBPs). The degradation of three NBHCs with different nitrogen atoms, benzotriazole (BTA), indazole (IDZ), and indole (IDO), and N-DBP formation during the ultraviolet light-emitting diode (UV-LED)/chlorine process deserve to be investigated. The extremely rapid IDO degradation was attributed to a fast electrophilic substitution of chlorine at the 3-position of the IDO molecule.

Dissolved black carbon in full-scale drinking water treatment plants: Occurrence and contribution to disinfection byproducts formation and cytotoxicity.

Dissolved black carbon (DBC) is a crucial precursor to disinfection byproducts (DBPs) in the drinking water disinfection process. However, the understanding of the presence and transformation of DBC within drinking water treatment plants (DWTPs) is still limited. This article systematically examined the presence and transport of DBC, in combination with the contribution to disinfection byproducts formation and cytotoxicity along the full-scale DWTPs.

Generation of DBPs from dissolved organic matter by solar photolysis of chlorine: Associated changes of cytotoxicity and reactive species.

Since elevated amounts of chlorine disinfectant were discharged into surface water, more attention should be paid to the reactions between dissolved organic matter (DOM) and chlorine under sunlight. However, disinfection byproducts (DBPs) formed from DOM by solar photolysis of chlorine, and changes of cytotoxicity during this process remain unclear. In this study, it was found that solar photolysis of chlorine significantly promoted the formation of aliphatic chlorinated DBPs and aromatic chlorinated DBPs (including chlorobenzoquinone) by 44.

The investigation of quenching conditions for the analysis of total organic halogen, aliphatic and aromatic halogenated disinfection byproducts formed from chlor(am)ination.

Total organic halogen (TOX) is used to describe total amount of halogenated DBPs. Typically, once a chlor(am)inated water sample is collected, it is necessary to add a quenching agent to quench the residual disinfectant so that further reactions to form more DBPs during the holding time can be prevented. In this study, we evaluated the effects of four quenching agents: ammonium chloride (NHCl), ascorbic acid, sodium sulfite (NaSO), and sodium thiosulfate (NaSO) on the decomposition of TOX, aliphatic and aromatic halogenated DBPs under various quenching conditions (quenching time, pH, quenching ratio, temperature).

Disinfection byproducts and their cytotoxicity contribution from dissolved black carbon in source water during chlor(am)ination.

Dissolved black carbon (DBC), the soluble component of black carbon, which mainly comes from the incomplete combustion of fossil fuels or biomass, is widely spread in source water and significantly contributes to the formation of dissolved organic matter (DOM). However, the origin of DBC in different types of source water in China has not been well studied, as well as its subsequent transformation and toxicity contribution during disinfection of source water DOM by chlor(am)ine. In this study, DBC from 17 different source water in East China at different seasons was collected.

Evolutions of dissolved organic matter and disinfection by-products formation in source water during UV-LED (275 nm)/chlorine process.

Ultraviolet light-emitting diode (UV-LED) is a promising option for the traditional low-pressure UV lamp, but the evolutions of DOM composition, the formation of disinfection by-products (DBPs) and their toxicity need further study in raw water during UV-LED/chlorine process. In UV-LED (275 nm)/chlorine process, two-dimensional correlation spectroscopy (2DCOS) analysis on synchronous fluorescence and UV-vis spectra indicated the protein-like fractions responded faster than the humic-like components, the reactive sequence of peaks for DOM followed the order: 340 nm→240 nm→410 nm→205 nm→290 nm. Compared to chlorination for 30 mins, the UV-LED/chlorine process enhanced the degradation efficiency of three fluorescent components (humic-like, tryptophan-like, tyrosine-like) by 5.

Degradation of natural organic matter and disinfection byproducts formation by solar photolysis of free available chlorine.

Environment disinfection effectively curbs transmission of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). However, elevated concentration of free available chlorine (FAC) in disinfectants can be discharged into surface water, generating toxic disinfection byproducts (DBPs). The impact of solar photolysis of FAC on natural organic matter (NOM) to form DBPs has not been well studied.

The effects of exogenous amino acids on production of microcystin variants in Microcystis aeruginosa.

Dissolved free amino acids are a significant component of dissolved organic nitrogen (DON) in natural waterbodies. The effects of four amino acids (glutamic acid, phenylalanine, leucine, and arginine) on the growth and microcystins (MCs) production of Microcystis aeruginosa were studied in batch culture. The profiles of five MCs variants and the expression levels of target genes involved in MCs biosynthesis and nitrogen metabolism were measured.

Occurrence of dissolved black carbon in source water and disinfection byproducts formation during chlorination.

Dissolved black carbon (DBC), the water-soluble component of black carbon, which is formed by incomplete combustion of fossil fuels or biochar, takes up about 10% of dissolved organic matter (DOM) in river water. However, the distribution of DBC in water environment especially in source water is not clear and as an important component of DOM, whether DBC can produce disinfection byproducts (DBPs) like other DOM during disinfection remains unknown. In this study, the DBC concentrations in seventeen source water samples from East China were measured.

Noncovalent interactions between fluoroquinolone antibiotics with dissolved organic matter: A H NMR binding site study and multi-spectroscopic methods.

Fluoroquinolone antibiotics (FQs) are considered to be emerging environmental contaminants that have been detected extensively in aquatic environment. It is of quite importance to explore FQs interacting with dissolved organic matter (DOM). The interactions of FQs with DOM were examined by nuclear magnetic resonance (NMR) spectroscopy, fluorescence quenching, UV-vis, Fourier transform infrared (FT-IR) spectroscopic techniques.

[Composition, Spatial Distribution Characteristics and Source Analysis of Chromophoric Dissolved Organic Matter in the Lanzhou Reach of the Yellow River].

Chromophoric dissolved organic matter (CDOM) in riverine systems can be affected by environmental conditions and land-use, and can thus provide important information regarding anthropogenic activities in surrounding landscapes. It can modify the optical properties of waters and affect the balance and availability of dissolved nutrients and metals in water bodies. However, the characteristics of CDOM in the Lanzhou reach of the Yellow River have not yet been reported.

Magnetic biochar-based manganese oxide composite for enhanced fluoroquinolone antibiotic removal from water.

Magnetic biochar-based manganese oxide composite (MMB) and raw biochar (BC) were synthesized via pyrolysis at a temperature of 500 °C under anoxic conditions of potato stems and leaves, characterized, and successfully used for the removal of norfloxacin (NOR), ciprofloxacin (CIP), and enrofloxacin (ENR) as representative compounds of fluoroquinolone antibiotics (FQs). Characterization results suggested that FeO and MnO are the dominant crystals in MMB. MMB possessed large surface area and pore volume than BC.