Volumen 51 (2020): Edición 1 (January 2020)

In this work, lightweight granules of zeolite Na-P1 based on expanded glass aggregates were synthesized for the application in oil products’ sorption. The sorption of gasoline, diesel and silicone oil tests were also conducted for raw expanded glass, zeolite A, clinoptilolite and mineral sorbent available at a fuel station. All sorbents were also characterized in terms of the phase composition (X-ray diffraction) and structure (infrared spectroscopy). The zeolite Na-P1 granules achieved the highest values of sorption capacities (1.8, 2.1 and 2.6 g/g, respectively), which makes them promising materials for oils’ removal.

Activated carbon was oxidised with concentrated nitric acid and impregnated with urea to form nitrogen-containing groups. Such a support was impregnated with cobalt, copper or silver nitrates to obtain catalysts for the selective catalytic reduction of nitrogen oxides with ammonia. Infrared spectra confirmed the formation of carboxylic and other organic oxygen-containing groups during oxidation. Nitrogen-containing species resulted from urea thermal decomposition. The metal-containing samples were hydrophilic. Cobalt and copper were present in the samples as small Co₃O₄ and CuO crystallites, while silver occurred in the form of large metallic crystallites, as seen from the X-ray diffraction patterns. Low temperature N₂ sorption revealed that all samples were microporous solids, and the chemical and thermal treatment did not change their textural properties. The copper admixture caused the highest NO conversion, but worsened the selectivity and thermal stability of functionalised carbon support.

Several mineralogically, chemically and texturally diverse minerals and waste materials were selected for the testing of elemental mercury capture in exhaust gas, namely tyre char resulting from the burning of pyrolytic rubber tyres, class C fly ash, mesoporous material type MCM-41 and glauconite. Each material’s mineralogical, chemical and textural characteristics were explored. In order to conduct experiments in conditions similar to those during the contact of sorbent with real coal exhaust fumes at a temperature of about 110-120°C, the experiments were carried out using a test device consisting of a furnace for burning powdered coals, a thermostatic cage for sorbent reactors and mercury gas analysers, which are able to measure and compare the effects of individual sorbents with exhaust gas. The study found that the best results for mercury sorption in the exhaust atmosphere were obtained for class C ash resulting from brown coal combustion.

The current work presents the results of seven sorbent samples investigated with respect to SO₂ capture. The sorbents’ reactivity and capacity indexes were determined, and the tests were carried out in accordance with the ‘classical’ procedure for limestone sorbents. The reactivity indexes (RIs) of the tested samples were in the range of 2.57 and 3.55 (mol Ca)/(mol S), while the absolute sorption coefficients as determined by the capacity index (CI) varied between 87.9 and 120.6 (g S)/(kg of sorbent). Porosimetric analysis was also carried out and the specific surface area of the samples was found to be between 0.2 and 1.7 m²/g. The number of micro-, meso- and macro-pores in individual samples was determined from the corresponding pore size distribution histograms, and the values of sorbent RIs and CIs were correlated with the samples’ total porosity and specific surface.

The paper concerns the applicability of silver nanoparticles for reducing the emission of odours. Silver nanoparticles were successfully adsorbed on three different dolomitic limestone samples. In the next stage, wastewater from the meat industry was mixed with sorbents modified with a variable content of silver nanoparticles. After 4 days and 7 days, the concentration of ammonia was examined spectrophotometrically. Also, the degree of reduction of total odour concentration by olfactometric method was carried out. Depending on the concentration of the silver nanoparticles on the sorbents, the concentration of ammonia was 15-42 μg/cm³ for nAg content equal to 0.08%, while for sorbents containing approximately 36% of nAg the concentration of ammonia was 0.09-16 μg/cm³. A leaching test of nanosilver from sorbents confirmed that the particles were bound with the sorbents by strong bonds. The percentage of eluted silver increased from 0.67% to 11%, with increased initial concentrations of nAg on the sorbents from 0.18% to 0.37%.