Photochemical and bacterial transformations of disinfection by-product precursors in water.

In situ grab sampling from source waters and water extraction from source materials are common methods for determining disinfection by-product (DBP) formation potential (FP) of water samples or reactivity of dissolved organic matter (DOM) in forming DBPs during chlorination. However, DOM, as the main DBP precursor, collected using these techniques may not represent the DOM reacting with disinfectants due to biogeochemical alterations during water conveyance to drinking water treatment facilities. In this study, we exposed leachates from fresh litter and associated decomposed duff to natural sunlight or K-12 for 14 d and evaluated the changes, if any, on the propensity to form trihalomethane (THM), haloacetonitrile (HAN), and chloral hydrate (CHD) during chlorination.

Photoelectrochemical degradation of Methylene Blue with beta-PbO2 electrodes driven by visible light irradiation.

Beta-PbO2 electrodes were prepared by electro-deposition and characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and linear sweep voltammetry. We confirmed pure (beta-PbO2 crystals were on the electrode and it had a high oxygen evolution potential. The photoactivity and photoelectrochemical (PEC) properties of the beta-PbO2 electrode were investigated under visible light irradiation (lambda > 420 nm) for the decolorization of Methylene Blue.

Reactivity of litter leachates from California oak woodlands in the formation of disinfection by-products.

Litter materials from forested watersheds can be a significant source of dissolved organic matter (DOM) to surface waters that can contribute to the formation of carcinogenic disinfection by-products (DBPs) during drinking-water chlorination. This study characterized the reactivity of DOM from litter leachates of representative vegetation in oak woodlands, a major plant community in the Foothill Region of California. Leachates from fresh and decomposed litter (duff) from two oak species, pine, and annual grasses were collected for an entire rainy season to evaluate their reactivity to form DBPs on chlorination.

Effective photocatalytic disinfection of E. coli K-12 using AgBr-Ag-Bi2WO6 nanojunction system irradiated by visible light: the role of diffusing hydroxyl radicals.

Urgent development of effective and low-cost disinfecting technologies is needed to address the problems caused by an outbreak of harmful microorganisms. In this work, we report an effective photocatalytic disinfection of E. coli K-12 by using a AgBr-Ag-Bi(2)WO(6) nanojunction system as a catalyst under visible light (lambda >or= 400 nm) irradiation.

Zn:In(OH)ySz solid solution nanoplates: synthesis, characterization, and photocatalytic mechanism.

Zn:In(OH)ySz solid solution nanoplates (Zn:In(OH)ySz-SSNs) with uniform nanoparticle size were synthesized through a simple sodium dodecyl sulfate (SDS)-assisted hydrothermal process. To achieve better photoabsorption in the visible light (VL) region and suitable redox potentials of the Zn:In(OH)ySz solid solution (Zn:In(OH)ySz-SS), the substitution of S(2-) for OH was carried out by adjusting the concentration of thiourea and SDS in the synthesis solution, while the doping of Zn2+ was realized by adjusting Zn2+ concentration. In addition, the morphology and crystallinity of Zn:In(OH)ySz-SSs were also controlled by the concentration of SDS.

Trihalomethane, haloacetonitrile, and chloral hydrate formation potentials of organic carbon fractions from sub-tropical forest soils.

Forest landscapes represent the major land-cover type for the watersheds of the East River, which is the source of water for 40 million people in South China. Forest soils with high levels of organic carbon are a potential terrestrial source of dissolved organic carbon (DOC) into the East River. DOC is of great concern, since it can form carcinogenic disinfection byproducts (DBPs) during drinking water treatment.