A. Concheso

Linz-Donawitz steel slag for the removal of hydrogen sulfide at room temperature.

Slags collected from the basic oxygen furnaces of two Linz-Donawitz steel making plants were tested as adsorbents for H(2)S removal at room temperature (298 K). Two different particle size fractions, namely <212 and 212-500 μm, were selected from the original slag samples. Dynamic adsorption tests were carried out using a column-bed configuration and retention capacities were calculated after bed exhaustion. Retention capacities as high as 180 mg of H(2)S g(-1) of slag were attained, in spite of the very low specific surface area of the steel slags. As expected, humidity played a crucial role in the removal of H(2)S. Particle size had also an important effect on the capacity of the adsorption beds. Analysis of the exhausted slags revealed considerable amounts of elemental sulfur on the surface of the particles. Sulfates were also found on the exhausted slags, especially on the 212-500 μm size fractions. The characterization of the slags prior and after the H(2)S adsorption experiments allowed us to postulate plausible mechanisms to understand the outstanding capacity of these steel byproduct for H(2)S adsorption.

Use of by-products from integrated steel plants as catalysts for the removal of trichloroethylene from groundwater

The removal of tricholoroethylene (TCE) has been investigated in this work through the Fenton-like process using different catalytic materials obtained from metallic by-products of the steel industry. These materials are the slag produced during the transformation of molten pig iron produced in a blast furnace into liquid steel (SLD), the dry particles (or dust) obtained from the bag filters installed in the coking installations to minimize diffuse emissions (POCA) and the dry particles obtained from the liquid sludge from the scrubber (LHA). This study aims to explore the potential of these materials for being used as permeable catalytic barriers to treat groundwater polluted with trichloroethylene (TCE). The wastes used as catalysts were chemically and physically characterized to determine their composition and porosity. The results of this study point out that among the different catalysts used LHA showed the highest catalytic activity to degrade TCE using hydrogen peroxide. Moreover, LHA was the most efficient catalyst using hydrogen peroxide due to its higher stoichiometric efficiency. It is thus concluded that LHA has a high potential to be combined with hydrogen peroxide in permeable catalytic barriers to remove organic compounds from groundwater.