Waste Brick Dust as Potential Sorbent of Lead and Cesium from Contaminated Water.

Adsorption properties of waste brick dust (WBD) were studied by the removing of Pb and Cs from an aqueous system. For adsorption experiments, 0.1 M and 0.5 M aqueous solutions of Cs and Pb and two WBD (Libochovice-LB, and Tyn nad Vltavou-TN) in the fraction below 125 µm were used. The structural and surface properties of WBD were characterized by X-ray diffraction (XRD) in combination with solid-state nuclear magnetic resonance (NMR), supplemented by scanning electron microscopy (SEM), specific surface area (S), total pore volume and zero point of charge (pH). LB was a more amorphous material showing a better adsorption condition than that of TN. The adsorption process indicated better results for Pb, due to the inner-sphere surface complexation in all Pb systems, supported by the formation of insoluble Pb(OH) precipitation on the sorbent surface. A weak adsorption of Cs on WBD corresponded to the non-Langmuir adsorption run followed by the outer-sphere surface complexation. The leachability of Pb from saturated WBDs varied from 0.001% to 0.3%, while in the case of Cs, 4% to 12% of the initial amount was leached. Both LB and TN met the standards for Pb adsorption, yet completely failed for any Cs removal from water systems.