University of Oulu

Samarina T, Guagneli L, Takaluoma E, Tuomikoski S, Pesonen J and Laatikainen O (2022) Ammonium removal by metakaolin-based geopolymers from municipal and industrial wastewaters and its sequential recovery by stripping techniques. Front. Environ. Sci. 10:1033677. doi: 10.3389/fenvs.2022.1033677

Ammonium removal by metakaolin-based geopolymers from municipal and industrial wastewaters and its sequential recovery by stripping techniques

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Author: Samarina, Tatiana1,2; Guagneli, Luca2; Takaluoma, Esther2;
Organizations: 1Research Unit of Sustainable Chemistry, Faculty of Technology, Oulu University, Oulu, Finland
2School of Engineering, Kajaani University of Applied Sciences, Kajaani, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.5 MB)
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Language: English
Published: Frontiers Media, 2022
Publish Date: 2022-11-17


In this study, a technical scheme of an ammonium recovery process from diluted municipal or industrial wastewaters was developed, and the main operational parameters of adsorption/desorption and air-stripping/acid-scrubbing or membrane units were examined. The proposed approach combines the removal of ammonium nitrogen by an ion-exchange mechanism on metakaolin-based geopolymers (MKGPs) followed by adsorbent regeneration. A regeneration agent was purified by the air-stripping technique or membrane technology. A ready-to-use market-grade fertilizer or industrial-grade ammonia water could be obtained as the final product. The properties and regeneration ability of MKGP, prepared from activated kaolinite clay, were compared with new geopolymer adsorbents based on papermill sludge (FS MKGP). Adsorption fixed-bed column experiments with continuously circulated regeneration solution purified by air-stripping or the membrane approach were conducted to determine the limits of the regeneration solution’s application. Sodium and potassium salts were tested as regeneration agents, and the influence of regeneration solution composition on ammonium removal and recovery rates was investigated. Based on a breakthrough curve analysis, the removal rate of ammonium N by FS MKGP was found to be 3.2 times higher than that by MKGP for actual wastewater samples. Moreover, there were substantial differences in the regeneration regime between the two adsorbents. For the air-stripping technique, a liquid-phase temperature of 45°C was minimal and enough for efficient ammonia transfer to the gaseous phase. For the membrane technique, a feed-phase temperature of 40°C was enough for removing ammonia from the regeneration solution, while no heating of a receiving phase was required.

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Series: Frontiers in environmental science
ISSN: 2296-665X
ISSN-E: 2296-665X
ISSN-L: 2296-665X
Volume: 10
Article number: 1033677
DOI: 10.3389/fenvs.2022.1033677
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
Funding: This study was conducted as part of the WaterPro project (number A74635 EAKR, Keski-Pohjanmaan Liitto/Kainuun Liitto/Pohjois-Pohjanmaan liitto) and REMAC project (KA11000, Karelia CBC).
Copyright information: © 2022 Samarina, Guagneli, Takaluoma, Tuomikoski, Pesonen and Laatikainen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.