Reaction Mechanism of Oxytetracycline Degradation by Electrogenerated Reactive Chlorine: The Influence of Current Density and pH.

A binary dimensionally stable anode Ti/TiO-RuO electrode was used to abate the antibiotic oxytetracycline (OTC) (CHNO) in chloride water. The anode was prepared using the Pechini method and subsequently characterized by X-ray diffraction, scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), and cyclic voltammetry (CV). The optimum values of the operational parameters affecting removal efficiency were determined using a 2 × 3 factorial design by screening (6.

Conformational Effects of [Ni (μ-ArS) ] Cores on Their Electrocatalytic Activity.

Two nickel complexes supported by tridentate NS ligands, [Ni (κ-N,S,S,S'-N {CH (MeC H R')S} ) ] (1; R'=3,5-(CF ) C H ) and [Ni (κ-N,S,S,S'-N {CH C H S} ) ] (2), were prepared as bioinspired models of the active site of [NiFe] hydrogenases. The solid-state structure of 1 reveals that the [Ni (μ-ArS) ] core is bent, with the planes of the nickel centers at a hinge angle of 81.3(5)°, whereas 2 shows a coplanar arrangement between both nickel(II) ions in the dimeric structure.

Spatial and seasonal mercury distribution in the Ayapel Marsh, Mojana region, Colombia.

Geographical and temporal changes of total mercury (T-Hg) concentrations in sediments, macrophytes and fish were evaluated in the Ayapel Marsh, Mojana, Colombia. Sampling was conducted during 2006-2007, including both rainy and dry seasons, and T-Hg was measured using atomic absorption spectroscopy. Distribution of T-Hg in sediments and the macrophyte Eichhornia crassipes showed that higher concentrations were found along the flooding pathway of the Cauca River.

Distribution of mercury in several environmental compartments in an aquatic ecosystem impacted by gold mining in northern Colombia.

Mercury (Hg) used in gold amalgamation is a major source of contamination in developing countries. Water, sediments, plankton, fish, and human samples from Grande Marsh, a Hg-polluted marsh located in the south of Bolívar, municipality of Montecristo, Colombia, were collected during both the rainy and the dry seasons (2003-2006), at three different sampling sites, and analyzed for total Hg (T-Hg) content. Water, sediment, seston, phytoplankton, and zooplankton T-Hg concentrations were 0.

Total mercury and methylmercury concentrations in fish from the Mojana region of Colombia.

Total mercury (T-Hg) and methylmercury (MeHg) concentrations have been measured in the muscle tissue of 16 fish species consumed in the Mojana region of Colombia. T-Hg analysis was performed by cold-vapor atomic-absorption spectroscopy (CV-ASS) and MeHg analysis by gas chromatography with electron-capture detection. Higher T-Hg and MeHg concentrations were detected in carnivorous species (T-Hg = 0.