Management of hazardous fly-ash energy waste in the adsorptive removal of diclofenac by the use of synthetic zeolitic materials

Abstract

Zeolite-carbon composites (Na-P1(C), Na-X(C)) and pure zeolites (Na-P1, Na-X) were synthesized from hazardous high-carbon fly ash waste (HC FA) via hydrothermal reaction with sodium hydroxide (NaOH). These solids were applied in the removal of diclofenac (DCF) from aqueous solution, with and without poly(acrylic acid) (PAA). The experiments included adsorption–desorption measurements, as well as electrokinetic and stability analyses. The obtained results showed that HC FA and Na-P1(C) had the greatest adsorption capacity towards DCF, i.e., 26.51 and 21.19 mg/g, respectively. PAA caused considerable decrease in the DCF adsorption due to the competition of both adsorbates of anionic character for active sites. For example, the adsorbed amount of DCF on Na-P1 without PAA was 14.11 mg/g, whereas the one measured with PAA was 5.08 mg/g. Most of prepared solids were effectively regenerated by the use of NaOH. Desorption degree reached even 73.65% in the single systems (with one adsorbate) and 97.24% in the mixed ones (with two adsorbates). Zeolitic materials formed suspensions of rather low stability, which underwent further deterioration in the organic molecules presence. All the results obtained in this study indicated that HC FA can be successfully managed in the removal of organic substances.

Fly Ash-Based Na-X Zeolite Application in Separation Process of Bovine Serum Albumin from Aqueous Solution in the Presence of Organic Substances with Anionic Character

“…In the case of PAA and DCF, a decrease in the σ 0 value is observed in the total examined pH range, whereas, in the case of SDS, it is in the range 7–9. This is due to the presence of negatively charged functional groups of the adsorbed organic molecules, which are located in the near-surface layer of the solution, outnumbering the groups directly interacting with the solid surface [ 31 ]. As a result of BSA addition to a system containing PAA or DCF, an enhancement in the effect is observed.…”

Adsorption Capacity of Carbon‐Silica Composites Towards Diclofenac in Poly(acrylic acid) Containing Systems: A Crucial Study on Common Wastewater Contaminants

“…C/SiO 2 was also examined for removal of copper (II) ions and polymer, achieving adsorption of 9.8 mg/g for Cu(II) and 35.72 mg/g for CT PAM‐25 % [14] . On the other hand, the topic of diclofenac removal in the presence of a polymer has also been raised previously in other papers on synthetic zeolites formed from fly ash energy waste [15,16,17] …”

“…[14] On the other hand, the topic of diclofenac removal in the presence of a polymer has also been raised previously in other papers on synthetic zeolites formed from fly ash energy waste. [15,16,17] The popular drug available over the counter (OTC -over the counter) from the group of non-steroidal anti-inflammatory drugs -diclofenac (DCF) -was selected for the study. Its consumption, and thus its occurrence in wastewater, is very high, and therefore it is important to find ways to safely remove it from the aqueous environment.…”