Oxidative destruction of chlorobenzene and o-dichlorobenzene on a highly active catalyst: MnOx/TiO2-Al2O3

A highly active catalyst, MnOx/TiO2-Al2O3, was prepared by impregnating MnOx species on TiO2-modified Al2O3. The TiO2 species in TiO2-Al2O3 support is in a monolayer dispersion, and the MnOx species is again highly dispersed on TiO2-Al2O3 Support. The total oxidation of chlorobenzene and o-dichlorobenzene on MnOx/TiO2-Al2O3 catalyst can be achieved at 300 degreesC and 250 degreesC respectively, at the space velocity of 8000 h(-1). The activity of MnOx/TiO2-Al2O3 catalyst (Mn loading 11.2 wt%) is gradually increased in the first 10-20 h and then keeps stable at least for the measured 52 h at 16,000 h(-1). Furthermore, no chlorinated organic byproducts are detected in the effluent during the oxidative destruction of chlorobenzene and o-dichlorobenzene. It is proposed that the partially chlorinated and highly dispersed manganese oxide on a monolayer TiO2-modified Al2O3 is responsible for the high and stable activity for the total oxidation of chlorinated aromatics. (C) 2001 Academic Press.

On-line concentration of peptides and proteins with the hyphenation of polymer monolithic immobilized metal affinity chromatography and capillary electrophoresis

An iminodiacetic acid (IDA)-type adsorbent is prepared at the one end of a capillary by covalently bonding IDA to the monolithic rods of macroporous poly(glycidyl methacrylate-co-ethylene dimethacrylate). Cu(II) is later introduced to the support via the interaction with IDA. By this means, polymer monolithic immobilized metal affinity chromatography (IMAC) materials are prepared. With such a column, IMAC for on-line concentration and capillary electrophoresis (CE) for the subsequent analysis are hyphenated for the analysis of peptides and proteins. The reproducibility of such a column has been proved good with relative standard deviations (RSDs) of dead time of less than 5% for injection-to-injection and 12% for column-to-column (n = 3). Through application on the analysis of standard peptides and real protein samples, such a technique has shown promising in proteome study.

Cluster-assisted multiple ionization of xenon and krypton by a nanosecond laser

Multicharged xenon and krypton ions with charge states up to Xe11+ and Kr11+ have been observed in laser ionization of a pulsed xenon or krypton beam by a 25 ns Nd-YAG laser with laser intensity of 10(10)-10(11) W cm(-2) at 532 nm. There is strong evidence to support that those multicharged ions come from cluster-assisted electron recolliding ionizations inside the cluster after multiphoton ionization of atoms in the cluster, the electron can gain its kinetic energy by inverse bremsstrahlung absorption from a laser field quickly.