Migration and morphological transformation patterns of heavy metals on sludge cells and extracellular polymeric substances (EPS) under the influence of different treatments

© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature..

The impediment of sludge resource utilization stems from the presence of heavy metals within the sludge matrix. To optimize heavy metal removal techniques from undried sludge, it is essential to study the distribution of heavy metals in the sludge flocs structure and the changes in morphology in the sludge cells after different treatments. In this study, the sludge was subjected to chemical treatments using citric acid (CA), EDTA, and saponin, as well as electrokinetic treatment at 2 V/cm. The distribution and migration of Cu, Ni, and Zn in sludge flocs after various treatment methods were analyzed. The heavy metals were found to migrate from intracellular to extracellular polymeric substances (EPS) without causing extensive sludge cell lysis. They gradually diffused outward with the dispersion of the EPS layer. The migration efficiency of the three heavy metals in the sludge flocs was Zn, Ni, and Cu. This was mainly related to the initial distribution and morphology of the heavy metals. Under the influence of chemicals and an electric field, the acid-soluble and reducible heavy metals in the cells partially migrated to the EPS, while the stable heavy metals transformed into an unstable state. Furthermore, the order of chemical reagents in terms of their effect on the migration efficiency of heavy metals was CA > EDTA > Saponin, owing to the varying binding strengths of heavy metals and their impact on the degree of loosening of the EPS. Especially after CA treatment a greater proportion of Cu, Ni, and Zn were transferred from the cells to the EPS. The acidification effect near the anode during electrokinetic treatment intensifies the migration of heavy metals. This study provides basic research for subsequent engineering optimization aimed at removing heavy metals from sludge.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:31

Enthalten in:

Environmental science and pollution research international - 31(2024), 14 vom: 23. März, Seite 21578-21590

Sprache:

Englisch

Beteiligte Personen:

Jia, Xiaoyu [VerfasserIn]
Wang, Yuxin [VerfasserIn]
Zhao, Miaomiao [VerfasserIn]
Zhang, Fan [VerfasserIn]
Li, Chen [VerfasserIn]
Ma, Degang [VerfasserIn]

Links:

Volltext

Themen:

9G34HU7RV0
Edetic Acid
Extracellular polymeric substances (EPS)
Heavy metals
Journal Article
Metals, Heavy
Migration
Morphological
Saponins
Sewage
Water Pollutants, Chemical

Anmerkungen:

Date Completed 19.03.2024

Date Revised 19.03.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1007/s11356-024-32398-8

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM368835537