Assumptions of powdered building wastes for selective adsorption of lead and cesium from water

Growing amount of building waste arising from the production of common and special materials has found new applications in useful and environmentally-friendly technologies. Waste brick dust (WBD) from the production of ceramic blocks, concrete slurry waste (CSW) generated in prestressed poles production and powdered waste from the treatment of technical stone (TSW) were tested as cheap and available adsorbents of lead (Pb) and cesium (Cs) from contaminated water. The structural, chemical and surface characteristics of materials were determined by X-ray diffraction (XRD), X-ray fluorescence (XRF), specific surface area (S_BET) and zero point of charge (pH_ZPC), model solutions of Cs⁺ and Pb²⁺ (0.1 mmol.L⁻¹ and 0.5 mmol.L⁻¹) were used in adsorption experiments. All sorbents were promising for quantitative Pb²⁺ removal (>99%) at a low sorbent consumption (∼10 g per 1 g of Pb). Generally worse Cs⁺ adsorption was related to the different thermodynamic and binding properties of hydrated Cs⁺ and Pb²⁺ ions. The efficiency of Cs⁺ adsorption decreased in the order: TSW (70–90%) >> WBD (25–50%) > CSW (10–15%). In terms of sorbent consumption, only TSW could be considered a perspective Cs⁺ sorbent in the technological use (∼10² g per 1 g of Pb). In order to assess the applicability of building wastes in adsorption technologies, the verification of Pb²⁺ and Cs⁺ stability in saturated sorbents will be necessary.