Use of waste ceramics in adsorption technologies

Waste brick dust (WBD) was tested as a potential sorbent of cationic and anionic contaminants, including radioactive residues. For adsorption experiments, model water solutions of highly toxic and/or ecologically harmful cations (Cd, Pb, Cs) and anions (As, Sb, Cr, U) were selected. The adsorption of Cd2+ and Pb2+ on WBD was most effective (>95%) at a very low sorbent dosage (up to 6 g L-1). In terms of anionic contaminants, U-VI was adsorbed as cationic complex particles [(UO2)(n)(OH)(2n-1)](+) almost quantitatively (>95%) at a sorbent dosage of 3 g L-1. The effective adsorption of As-V (>90%) occurred at around a dosage of 15 g L-1. The adsorption of Cs+, Cr-VI and As-III on WBD was almost ineffective. Except for Cs+ and Cr-VI, all investigated ions were adsorbed according to the Langmuir isotherm model, at the theoretical adsorption capacities Q(t) approximate to approximately 0.1 mmol g(-1) for Cd2+, Pb2+ and U-VI, and approximately. 0.04 for As-V and As-III. The leachability of toxic particles from saturated WBD was very low for selectively adsorbed particles (approximate to 0.01-0.08% wt.) and their stability decreased in the order: Pb2+ approximate to Cd2+ > U-VI > As-V > As-III >> Cs+ >> Cr-VI. The approximate consumption of WBD per gram of toxic element was found to be about approximate to 60 g for Pb2+ and U-VI , approximate to 100 g for Cd2+ and >400 g for As-V. (C) 2016 Elsevier B.V. All rights reserved.