Promising Stability of Gold-Based Catalysts Prepared by Direct Anionic Exchange for DeNO x Applications in Lean Burn Conditions

Supported gold catalysts on γ-Al₂O₃ have been investigated in the catalytic reduction of NO _x in simulated Diesel exhaust gas conditions. Different parameters have been examined essentially the mode of gold incorporation via classical deposition–precipitation and anionic exchange methods and the nature of the pre-activation thermal treatment. The resistance to thermal ageing under reactive conditions at 500 °C was found completely different with a significant rate enhancement on anionic-exchange samples. Further comparisons also show that the nature of the pre-activation thermal treatment influences the extent of surface reconstructions during thermal ageing with a detrimental effect of reductive pre-treatment on the catalytic performances.     

PAHs in Sediments Contaminated by the Haven Oil Spill. (Genoese Bay)

Sediment samples were collected 40 months after the wreckage of the HAVEN off shore Arenzano, facing the Genoese coast, at 300 to 500 m depth, (wreckage zone) and analysed by UV fluorescence spectroscopy and CG/MS. PAHs as alkylated naphtalene, fluorene, phenanthrene, dibenzothiophene series have been studied. Analytical results reveal – 1° – a great alteration of alkylated homologues compared to parent compounds - 2° - the appearance of anthracene (absent in the original crude oil) in samples – 3° – a relative increase of high molecular weight PAHs (4–5 rings and more) as benzo(ghi)perylene and indeno(cd)pyrene. These changes result from the partial burning of the contaminant oil. A beginning of biodegradation is observed for alkylated phenanthrenes.     

Covalent Isoresonance

Two molecular species are defined to be isoresonant if each have like numbers of the same (type of) bonds and there is an isomorphism between superpositions of pairs of Kekulé structures giving equivalent interaction patterns (as appear in Hamiltonian matrices). Thus a close physico-chemical correspondence follows, as predicted by a variety of semiempirical quantum-chemical models, and thence presumably for corresponding molecules. Notably simple structural criteria sufficient for isoresonance are found.     

Briquetting the carbon phase from the sludge ponds at the Anzhersk deposit

The briquetting of coal slurries from the Anzhersk deposit in the Kuznets Basin is investigated. Petroleum binder and sodium lignosulfonate are employed. The solid carbon phase from the sludge ponds (ash content up to 35%) has adequate briquetting properties when petroleum binder is added. The use of sulfite waste liquor at pressures of 80–100 MPa yields mechanically strong briquets that require additional water protection.     

Introduction of biochemical wastewater purification at OOO Mechel-Koks (stage I)

Systems for mechanical and biological wastewater purification have been introduced at OOOMechel-Koks. This represents the first stage of a two-stage project to introduce biochemical purification. Results obtained in the adjustment and debugging of the systems are presented.