University of Oulu

Maziarz, P., Matusik, J., & Leiviskä, T. (2019). Mg/Al LDH Enhances Sulfate removal and Clarification of AMD Wastewater in Precipitation Processes. Materials, 12(14), 2334.

Mg/Al LDH enhances sulfate removal and clarification of AMD wastewater in precipitation processes

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Author: Maziarz, Paulina1; Matusik, Jakub1; Leiviskä, Tiina2
Organizations: 1Department of Mineralogy, Petrography and Geochemistry; Faculty of Geology, Geophysics and Environmental, Protection; AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow, Poland
2Chemical Process Engineering, University of Oulu, P.O. Box 4300, FIN-90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.8 MB)
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Language: English
Published: Multidisciplinary Digital Publishing Institute, 2019
Publish Date: 2019-08-02


The sulfate removal from acid mine drainage (AMD) water (initial concentration: 5301 mg/L) was investigated by precipitation and/or adsorption using calcium hydroxide (Ca(OH)2) and synthetic layered double hydroxide (LDH) of the Mg/Al type. The exclusive use of LDH efficiently removed sulfates (64.2% reduction); however, alteration of its structure was observed due to low pH. The use of Ca(OH)2 in different doses calculated in relation to gypsum stoichiometry allowed to achieve an 86% removal of sulfates. Depending on the equilibrium pH, gypsum or ettringite were the main identified phases. The two-step removal, involving the use of Ca(OH)2 followed by LDH, was less efficient than the use of the Ca(OH)2/LDH mixture when the stoichiometric amount of Ca(OH)2 in relation to gypsum was applied. The application of mixture resulted in a fast pH increase, which prevented destruction of the LDH structure. Most importantly, the use of mixture significantly reduced the sludge volume and enhanced its settling velocity.

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Series: Materials
ISSN: 1996-1944
ISSN-E: 1996-1944
ISSN-L: 1996-1944
Volume: 12
Issue: 14
Article number: 2334
DOI: 10.3390/ma12142334
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
1171 Geosciences
218 Environmental engineering
Funding: This work was supported by the EDUFI Fellowship (TM-17-10657) from the Finnish National Agency for Education and by the K.H. Renlund Foundation.
Copyright information: © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (