Use of waste ceramics in adsorption technologies

- Waste ceramics was found as perspective sorbent of toxic contaminants.
- The adsorption of toxic ions by waste ceramics may be applicable in decontamination technologies.
- Waste ceramics belongs to low-cost and environmentally friendly materials.
- Waste ceramics saturated with toxic ions may be incorporated into a building material.

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, UVI 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 AsV (> 90%) occurred at around a dosage of 15 g L− 1. The adsorption of Cs+, CrVI and AsIII on WBD was almost ineffective. Except for Cs+ and CrVI, all investigated ions were adsorbed according to the Langmuir isotherm model, at the theoretical adsorption capacities Qt ≈ approximately 0.1 mmol g− 1 for Cd2 +, Pb2 + and UVI, and approximately. 0.04 for AsV and AsIII. The leachability of toxic particles from saturated WBD was very low for selectively adsorbed particles (≈ 0.01-0.08% wt.) and their stability decreased in the order: Pb2 + ≈ Cd2 + > UVI > AsV > AsIII ≫ Cs+ ≫ CrVI. The approximate consumption of WBD per gram of toxic element was found to be about ≈ 60 g for Pb2 + and UVI, ≈ 100 g for Cd2 + and > 400 g for AsV.