Since it was introduced in 1997, in-tube solid-phase microextraction (in-tube SPME), which uses a capillary column as extraction device, has been continuously developed online coupled to LC systems SPME-LC). In the last decade, new couplings have evaluated on basis of state-of-the-art instruments, including direct coupling SPME MS/MS systems, without chromatographic separation, for high-through...

A rigours mathematical model based on the bivariate population balance frame work (the base of LLECMOD ‘‘Liquid-Liquid Extraction Column Module’’) for the steady state and dynamic simulation of pulsed liquid-liquid extraction columns is developed. The model simulates the coupled hydrodynamic and mass transfer for pulsed (packed and sieve plate) extraction columns. It is implemented using visual...

Many antibiotics regarded as emerging contaminants have been frequently detected in soils and groundwater; however, their transport behaviors in soils remain largely unknown. This study examined the transport of two antibiotics, sulfamethoxazole (SMZ) and ciprofloxacin (CIP), in saturated porous media. Laboratory columns packed with quartz sand was used to test the effects of solution pH and io...

Department of Defense operational ranges may become contaminated by particles of explosives residues (ER) as a result of low-order detonations of munitions. The goal of this study was to determine the extent to which particles of ER could migrate through columns of sandy sediment, representing model aquifer materials. Transport experiments were conducted in saturated columns (2 × 20 cm) packed ...

Structured packings are widely used in distillation columns to separate various types of mixtures. These have an ordered structure, which ensures more uniform conditions for interaction counter-current flows liquid and vapor than the random a small hydraulic resistance. Nevertheless, with diameter 0.5 m, formation large-scale non-uniformity distribution flow parameters over packing cross-sectio...

Flow-through columns packed with "aged" zero-valent iron (ZVI) between layers of soil and sand were constructed to mimic a one-dimensional permeable reactive iron barrier (PRB). The columns were continuously fed RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine, ca. 18 mg l(-1)) for over one year. Two columns were bioaugmented with dissimilatory iron reducing bacteria (DIRB) Shewanella algae BrY or ...

Soil fumigants are becoming an important source of volatile organic compounds (VOCs) in air, especially in some agricultural areas. In this study, we used thiourea to construct a reactive surface barrier (RSB) at the soil surface for reducing 1,3-dichloropropene (1,3-D) volatilization. The agrochemical thiourea could rapidly transform volatile 1,3-D to nonvolatile products via an SN2 nucleophil...

Replacing pressure-driven flow with electroosmotic flow in chromatography with packed capillary columns results in a new and powerful analytical technique, combining the advantages of high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE): capillary electrochromatography (CEC). In essence, it involves packing CE capillaries with HPLC stationary phases and applying a vo...