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Eleonora Sočo and Jan Kalembkiewicz

Abstract

The study investigates chemical modifications of coal fly ash (FA) treated with HCl or NH4HCO3 or NaOH or Na2edta, based on the research conducted to examine the behaviour of Cd(II) and Pb(II) ions adsorbed from water solution on treated fly ash. In laboratory tests, the equilibrium and kinetics were examined applying various temperatures (293 - 333 K) and pH (2 - 11) values. The maximum Cd(II) and Pb(II) ions adsorption capacity obtained at 293 K, pH 9 and mixing time 2 h from the Langmuir model can be grouped in the following order: FA-NaOH > FA-NH4HCO3 > FA > FA-Na2edta > FA-HCl. The morphology of fly ash grains was examined via small-angle X-ray scattering (SAXS) and images of scanning electron microscope (SEM). The adsorption kinetics data were well fitted by a pseudo-second-order rate model but showed a very poor fit for the pseudofirst order model. The intra-particle model also revealed that there are two separate stages in the sorption process, i.e. the external diffusion and the inter-particle diffusion. Thermodynamics parameters such as free energy, enthalpy and entropy were also determined. A laboratory test demonstrated that the modified coal fly ash worked well for the Cd(II) and Pb(II) ion uptake from polluted waters.

Open access

Jan Kalembkiewicz, Elżbieta Sitarz-Palczak, Eleonora Soćo, Danuta Nowak and Irena Trojnar

Abstract

The atmospheric fallout over the Rzeszów town was investigated. Intensity of dustfall (quarterly periods, 2011.2012) and its physicochemical properties (acid-base character, solubility and sequential solubility, mobile fractions) were investigated. The intensity of dustfall was variable from 25 to 83 g·m.2 and depended on the season. Contents of metals in precipitation were diverse with quantities exceeding 1%: Fe, K, Ca, Na, in 0.1.1%: Mg, Zn, Na, Ca, Mn, Ni, Co, Cr, and less than 0.1%: Cu, Bi, Cr, Mn, Ni, Pb. It was found that the dustfall is a possible source of metals. The atmospheric fallout can enlarge a pool of metals in soils from 0.18% up to 80%.