Sorption experiments of the Cd, Zn, and Pb(II) ions from aqueous solutions on waste dolomite powder were investigated. Waste dolomite powder is inconvenient during storage due to fine particle size; therefore, its practical application is needed. The sorption experiments were conducted with variables: initial metal concentration (500, 1000, and 2000 mg/dm³) in single- and multi-element solutions, adsorbent dose (0.5, 1, and 2 g), and contact time (45, 90, and 180 min). Results showed that dolomite powder removed all ions from experimental solutions. For multi-element solution, Pb(II) was adsorbed almost in 100% at the initial concentration equal to 2000 mg/dm³. For Cd and Zn, sorption properties decreased with the increase in the initial metal concentration and the maximum values at the initial metal concentration of 500 mg/dm³ were 42 and 47%, respectively. The results suggest that waste dolomite powder can be considered for application as sorbent in wastewater purification.

Production of fly ash zeolites may be an attractive method for the utilization of solid wastes from the energy sector. Different methods of synthesis often yield a variety of zeolite types, thereby affecting the properties of the resulting materials. The attention paid to carbon dioxide emission reduction technologies fully justifies the study of the sorption behaviours of fly ash zeolites synthesized by different methods. This work investigates the sorption properties of fly ash zeolites synthesized with different methods using CO₂. Sorption capacity and adsorption isotherms were determined following the volumetric method and textural parameters were resolved according to the Dubinin-Astakhov (DA) method. The CO₂ sorption capacity was in the range 0.24–4.16 mmol/g. The relationships between structure and sorption behaviour were studied for each synthesis method. Some strong similarities between commercial zeolites and fly ash zeolites were found. The mechanism for sorption was proved to be physisorption which is fully reversible under selected conditions. The observed trends were used to identify the best sorbent.