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.

Formation of Aromatic Halogenated Disinfection Byproducts in Swimming Pool Water during Chlorination: Organic Precursors and Mechanisms.

Disinfection byproducts (DBPs) in swimming pool water are a significant public health concern. The formation of aromatic halogenated DBPs in swimming pool water has not been clarified previously. In this study, the occurrence of aromatic halogenated DBPs in swimming pool water was examined, and it was found that halohydroxybenzoic acids (HBAs) and halobenzoquinones (HBQs) were the most dominant aromatic halogenated DBPs in swimming pool water that were continuously formed.

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.

The effects of Cu-phenanthrene co-contamination on adsorption-desorption behaviors of phenanthrene in soils.

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants in the environment, which are teratogenic, carcinogenic, and mutagenic. Co-contamination of PAHs and heavy metal commonly exists in soil. In this study, 20 types of soils with different properties in China were collected and comprehensively characterized.

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.

Cloning, overexpression, and characterization of a highly active endoinulinase gene from Aspergillus fumigatus Cl1 for production of inulo-oligosaccharides.

In this study, an endoinulinase gene from Aspergillus fumigatus was cloned and overexpressed in Pichia pastoris. A maximum activity, 3860 U/ml, of the recombinant endoinulinase was obtained by using a high cell-density fermentation approach. The recombinant endoinulinase with a molecular weight of 58 kDa was purified for further enzymatic investigation.