Catalysts based on silver supported on foam ceramics and modified by Zr, Ce and La oxides have been studied in the process of partial oxidation of methanol to formaldehyde. The foam catalysts exhibit high catalytic, mechanical and gas -dynamic properties exceeding the characteristics of conventional crystalline and supported silver samples. Modifying additives of Zr and Ce oxides raise activity...

Water flow and TiO2 nanoparticle (NP) transfer in a fractured hard-rock aquifer were studied in a tracer test experiment at a pilot site in Brittany, France. Results from the Br tracer test show that the schist aquifer can be represented by a two-layer medium comprising i) fractures with low longitudinal dispersivity in which water and solute transport is relatively fast, and ii) a network of s...

Laboratory tracer experiments were conducted to investigate solute transport in 12.5-m long, horizontally placed soil columns during steady saturated water flow. Two columns having cross-sectional areas of 10 x IOcm’ were used: a uniformly packed homogeneous sandy column and a heterogeneous column containing layered, mixed, and lenticular formations of various shapes and sizes. The heterogeneou...

1 2 A detailed model was formulated to describe the non-passive transport of water-soluble 3 chemicals in the unsaturated zone and used to illustrate one-dimensional infiltration and 4 redistribution of alcohol-water mixtures. The model includes the dependence of density, 5 viscosity, surface tension, molecular diffusion coefficient in the liquid phase, and gas-liquid 6 partition coefficient on...

Hydrodynamic dispersion is an important factor controlling contaminant migration in the subsurface environment. However, few comprehensive data sets exist for critically evaluating the impact of travel distance and site heterogeneity on solute dispersion. Therefore, a series of field-scale experiments using tritiated water (H2O), and bromide (Br) as tracers was conducted on the U.S. Department ...

Expansion of human activities causes dispersion of pollutants in the subsurface environment. The fate and movement of dissolved substances in soils and groundwater has generated considerable interest out of concern for the quality of the subsurface environment. Many analytical solutions for partial differential equations exist in soil science. Numerical solutions are more general, and often mor...