Semiconductor-mediated photocatalysed degradation of two selected priority organic pollutants,benzidine and 1,2-diphenylhydrazine,in aqueous suspension

The photocatalysed degradation of two selected priority organic pollutants, namely benzidine (1) and 1,2-diphenylhydrazine (DPH, 2) has been investigated in aqueous suspensions of titanium dioxide (TiO2) under a variety of conditions employing a pH-stat technique. The degradation was studied by monitoring the change in substrate concentration of the model compound employing HPLC analysis and the decrease in total organic carbon content, respectively, as a function of irradiation time. The degradation kinetics were studied under different conditions such as reaction pH, substrate and photocatalyst concentration, type of TiO2 photocatalyst and the presence of alternative additives such as H2O2, KBrO3 and (NH4)2S2O8 besides molecular oxygen. The degradation rates and the photonic efficiencies were found to be strongly influenced by the above parameters. Toxicity tests for the irradiated samples of benzidine measuring the luminescence of bacteria Vibrio fischeri after 30 min of incubation were also performed. 4-amino-biphenyl (7) and hydroquinone (13) were identified as intermediate products by GC/MS technique and probable pathways for the formation of the products are proposed.     

Eine ternäre Phase im Dreistoffsystem Aluminium-Kupfer-Titan

The Science of Nature -     

Optical and microphysical properties of severe haze and smoke aerosol measured by integrated remote sensing techniques in Gwangju,Korea

Aerosol optical and microphysical parameters from severe haze events observed in October 2005 at Gwangju, Korea (35.10°N, 126.53°E) were determined from the ground using a multi-wavelength Raman lidar, a sunphotometer, and a real-time carbon particle analyzer and from space using satellite retrievals. Two different aerosol types were identified based on the variability of optical characteristics for different air mass conditions. Retrievals of microphysical properties of the haze from the Raman lidar indicated distinct light-absorbing characteristics for different haze aerosols originating from eastern and northern China (haze) and eastern Siberia (forest-fire smoke). The haze transported from the west showed moderately higher absorbing characteristics (SSA = 0.90 ± 0.03, 532 nm) than from the northern direction (SSA = 0.96 ± 0.02). The organic/elemental carbon (OC/EC) ratio varied between 2.5 ± 0.4 and 4.1 ± 0.7.     

Teil I: Braucht die Landwirtschaft Umweltmanagementsysteme?

The farming community is today faced with requests by various interest groups to implement environmental management systems (EMS). The series of items shows principle theoretical questions of the method and the advantages of EMS (part I and II), presents the practical outcome (part III) and give a recommendation for potential users of EMS in agricultural systems (part IV). The study conducted outlines the method of the implementing an EMS according to the Environmental Management and Audit System (EMAS) and ISO 14001. Further advantages and disadvantages for the agricultural industry are addressed. Even though terms such as site can not easily be defined or problems with open material cycles and structural particularity of agricultural farms there appears to be a benefit to implement. The transparency and documentation of the material flow as well as the economical benefits of an optimized organization count towards the EMS. Further EMS can be a means to strengthen the argumentative position for example with the public, authorities, banks or insurance. This concurs with minimizing company liabilities and obtaining governmental privileges (deregulation).