Waste fly ash, with both low (with the addition of vermiculite) and high contents of unburned coal, were subjected to hydrothermal syntheses aiming to obtain zeolite composite materials—zeolite + vermiculite (NaX–Ver) and zeolite + unburned carbon (NaX–C). The composites were compared with parent zeolite obtained from waste fly ash with a low content of unburned carbon (NaX–FA). In this study, the physicochemical characteristics of the obtained materials were evaluated. The potential application of the investigated zeolites for the adsorption of ammonium ions from aqueous solutions was determined. Composite NaX–Ver and parent zeolite NaX–FA were characterized by comparable adsorption capacities toward ammonium ions of 38.46 and 40.00 mg (NH4+) g−1, respectively. The nearly 2-fold lower adsorption capacity of composite NaX–C (21.05 mg (NH4+) g−1) was probably a result of the lower availability of ion exchange sites within the material. Adsorbents were also regenerated using 1 M NaCl solution at a pH of 10 and subjected to 3 cycles of adsorption–desorption experiments, which proved only a small reduction in adsorption properties. This study follows the current trend of waste utilization (fly ash) and the removal of pollutants from aqueous solutions with respect to their reuse, which remains in line with the goals of the circular economy.

No abstract

Strongly weathered red and yellow soils with thick (490-900 mm) humic Al horizons (Haplohumox and Palehumults) derived from sandstones and basic igneous rocks, and occurring near the east coast of Southern Africa, are described and discussed in terms of their distribution, morphology, texture, mineralogy, chemistry, genesis and classification. The high organic matter content (2-5%c) of the A l contributes significantly to a high pH-dependent negative charge, probably to poorer crystallinity of goethite and kaolinite and to the transformation of haematite to goethite. Varying proportions of kaolinite and gibbsite reflect different soil ages within these old landscapes. The yellow colour of aluminous goethite, the main pedogenic iron oxide, is masked in the A1 by organic matter and in red B2 horizons by haematite. Temperature may have influenced the broad pattern of occurrence of red and yellow B2 horizons. These soils need not, as previously suggested,

The de-icing of roads and streets in the winter season is a necessity in many European countries, where the mean day temperature drops below 0°C for long periods. Among the many chemicals used for winter road maintenance, the most popular in Poland is sodium chloride in various forms and mixtures, due to its relatively low price and availability. This agent, however, contributes to the increase of salinity in the soil environment and may lead to disturbances in soil properties and premature plant necrosis. The impact of the usage of chloride salts on the soil environment was researched in Krakow's city centre by means of the examination of soil samples collected prior to the de-icing season (November) and afterwards (February) as well as snow samples taken in February. A general deterioration of the examined parameters (pH, conductivity, chloride concentrations, carbonate concentrations) was observed after the winter season, but still the results for most samples did not pose a serious threat to the soil environment or plants. This was mainly the result of the fact that the winter seasons in European countries have become increasingly mild and warm, which contributes to decreased usage of chloride salts. However, the state of soils in the Main Square was disturbing, as demonstrated by the clearly elevated chemical parameters of samples, despite a ban on the use of salt in this area. These results indicate the most probable reason for the withering of trees growing there, leading to them being frequently replaced.

Eleven soil samples derived from a black vertisol (Arcadia form) and. a red alfisol (Short lands form) were investigated by means of X-ray fluorescence as well as standard soil chemical and physical analyses. The profiles developed from Jurassic basalt under identical macro-environmental conditions and were situated 35 m apart. The clay content was significantly higher in the black solum, as were cation exchange capacity and organic matter, while the proportion of secondary iron phases was markedly lower. Differences in the major element composition of the soil fractions as a whole occurred with profile development, with gains in Si concomitant with a depletion of particularly Fe, Mg, Na and Ca. Gains and losses within each profile were most obvious between the two saprolite horizons and at the saprolite/solum boundary. Only small variations occurred within the solums. Trends in the major element composition of the clay fractions with decreasing depth consisted of a linear accumulation of AI and loss of Mg and Si; these were more pronounced in the red solum. Differences in element proportions between the two profiles correlated with parent material characteristics. The contrast in pedochemical development is explicable predominantly in terms of bedrock contours and related lateral movement characteristics of soil solutions and/or clay minerals. The.influx of detritus was significant.Elf grondmonsters van 'n swart vertisol (Arcadiavorm) en 'n rooi alfisol (Shortlandsvorm) is met behulp van X-straal-fluorisensiespektroskopie en standaard grondchemiese en -fisiese metodes ondersoek. Die profiele het ontwikkel uit jurasiese basalt onder identiese makro-omgewingstoestande en is 35 m ·uitmekaar gelee. Die klei-inhoud, katioonuitruilkapasiteit en organiese materiaal was betekenisvol hoar in die swart solum terwyl die sekondere ysterminerale inhoud merkbaar laer was. Verskille in die hoofelementsamestelling van die totale grondfraksie kom ooreen met die profielontwikkelingstadia, met 'n toename in Si en 'n gepaardgaande afname in Fe, Mg, Na en Ca. Toename en verliese was betekenisvol tussen die twee saproliethorisonne en ook by die saprolietlsolum grens; slegs klein verskille het in die solums voorgekom. Tendense in die hoofelementsamestelling van die kleifraksies met 'n afname in diepte bestaan uit 'n liniere akkumulasie van AI en verlies van Mg en Si wat meer opvallend is in die rooi solum. Verskille in elementverhoudings tussen die twee profiele korreleer goed met die eienskappe van die moedermateriaal. Die kontras in pedocnemiese ontwikkeling is verklaarbaar hoofsaaklik in terme van vaste gesteentekontoere en verwante lateraIe beweging van grondoplossings en/of kleiminerale. Die invloei van detritus in die solum was betekenisvol.