University of Oulu

Prem Kumar Seelam, Harisankar Sreenivasan, Satu Ojala, Satu Pitkäaho, Tiina Laitinen, He Niu, Riitta L. Keiski, Mirja Illikainen, Modified geopolymers as promising catalyst supports for abatement of dichloromethane, Journal of Cleaner Production, 2020, 124584, ISSN 0959-6526, https://doi.org/10.1016/j.jclepro.2020.124584

Modified geopolymers as promising catalyst supports for abatement of dichloromethane

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Author: Seelam, Prem Kumar1; Sreenivasan, Harisankar2; Ojala, Satu1;
Organizations: 1Environmental and Chemical Engineering Research Unit, Faculty of Technology, P.O. Box 4300, University of Oulu, Finland
2Fibre and Particle Engineering Research Unit, Faculty of Technology, University of Oulu, P.O. Box 4300, FI90014, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.8 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2020112092246
Language: English
Published: Elsevier, 2020
Publish Date: 2020-11-20
Description:

Abstract

Geopolymers have not been extensively employed as catalytic materials despite of their zeolite-resembling Si–Al structure. Geopolymerization offers a novel way for preparation of catalysts and possibility to use waste or industrial side-stream derived raw material as a resource for catalyst manufacturing. This work concentrates on metakaolin-based geopolymer materials that were prepared, characterized and tested as alternative environmentally benign catalyst supports for the oxidation of dichloromethane. The geopolymers with the Si/Al ratio of 1.5 were modified with HCl to increase their specific surface area, which is important in catalytic applications. Significant increase in specific surface areas was achieved via leaching of Na and Al from the geopolymer structure. Highest specific surface areas achieved for calcined geopolymers were over 500 m²g⁻¹. Use of acid concentrations higher than 1 M led to the dehydroxylation of the geopolymer. Dehydroxylation decreased the total acidity of geopolymer through the loss of the Brønsted acid sites, which are responsible for the adsorption of dichloromethane in the beginning of the catalytic reaction. Absence of Brønsted acid sites was observed by the formation of CH₂O as the only reaction intermediate. The best result in the dichloromethane oxidation was found with the geopolymer treated with 1 M HCl. Without using any additional active sites, the maximum dichloromethane conversion of 90% was reached at 525 °C with the maximum HCl yield of 83%. This result indicates the good potential of modified geopolymers to be used as catalyst supports in environmental applications.

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Series: Journal of cleaner production
ISSN: 0959-6526
ISSN-E: 1879-1786
ISSN-L: 0959-6526
Volume: In press
DOI: 10.1016/j.jclepro.2020.124584
OADOI: https://oadoi.org/10.1016/j.jclepro.2020.124584
Type of Publication: A1 Journal article – refereed
Field of Science: 218 Environmental engineering
215 Chemical engineering
Subjects:
Funding: The authors would like to acknowledge financial support of Academy of Finland received via InStreams [grant #326291: University of Oulu proliferation action towards inorganic side stream utilization] and ELECTRA projects [grant#319448 and #289266], and I4FUTURE MSC-COFUND doctoral programme (Marie Skłodowska-Curie COFUND Grant Agreement no. 713606).
EU Grant Number: (713606) I4FUTURE - Novel Imaging and Characterisation Methods in Bio, Medical, and Environmental Research and Technology Innovations
Academy of Finland Grant Number: 319448
289266
Detailed Information: 319448 (Academy of Finland Funding decision)
289266 (Academy of Finland Funding decision)
Copyright information: © 2020 The Author(s). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
  https://creativecommons.org/licenses/by-nc-nd/4.0/