Kinetic study of metal ion adsorption from wastewater onto coal industry by-products.

A comparative study on the use of fly ash (FA) and natural clinker (NC) as heavy metal adsorbents from polluted water was carried out using adsorption experiments at room temperature. The concentrations of heavy metals in the filtrates were determined by inductively coupled plasma-atomic emission (ICP-AE) spectrometry. In batch mode adsorption studies, removal increased with an increase of contact time, adsorbent amount and solution pH. Adsorption of metals from artifitially poluted sulution (APS) was Cr>Cu>Pb>Ni>Zn, whereas from acid mine drainage (AMD) was Pb>Zn>As>Fe>Cr>Cu>Ni. The Lagergren's first-order rate constants were calculated for specific initial concentrations of metal ions, giving an excellent fit as indicated by the correlation coefficient (R²), with values close or equal to 1 for treated APS and from 0.25 to 0.99 for treated AMD. Data from this study reveal that metal cations from aqueous solution can be adsorbed successfully in significant amounts by the used adsorbents. [ABSTRACT FROM AUTHOR]