LAUSR

Waste building sludge (WBS) originating in the production of concrete prestressed poles (CSW) and technical stone (TSW) used in original and Fe-modified forms (CSWFe, TSWFe) was tested as an environmentally friendly and cheap sorbent of selected cations (Cd2+, Pb2+, Cs+) and anions (AsO43−, PO43−, CrO42−) from water. The experiments were performed with 0.1 and 0.5 mmol·L−1 model solutions in a batch manner at laboratory temperature. Adsorption data were fitted with the Langmuir model. The adsorption of cations (Pb2+ and Cd2+) ran almost quantitatively (>97%) on both CSW and TSW. Cesium (Cs+) adsorption on TSW reached 80%, while in the case of CSW, it was ineffective. The modification of CSW and TSW with FeII (CSWFe and TSWFe) improved their adsorption selectivity to anions by up to 70%. The adsorption of PO43− and AsO43− ran quantitatively (>98%) on modified CSWFe and TSWFe and also on initial CSW, while CrO42− was effectively adsorbed (≈80%) on TSWFe only. The adsorption affinity of tested ions in terms of adsorption capacity and sorbent consumption declined in order as follows: Pb2+ ≈ Cd2+ >> Cs+ for cations and AsO43− ≈ PO43− > CrO42− for anions.