Takaya, CA, Parmar, KR, Fletcher, LA et al. (1 more author) (2019) Biomass-derived carbonaceous adsorbents for trapping ammonia. Agriculture, 9 (1). 16. ISSN 2077-0472
Abstract
The preparation of low-cost carbonaceous adsorbents for nitrogen recovery is of interest from agricultural and waste management perspectives. In this study, the gaseous ammonia (NH3) and aqueous ammonium (NH4+) sorption capacities have been measured for different types of carbonaceous chars produced under different conditions. The study includes a comparison of an oak-based hydrochar produced from hydrothermal carbonisation (HTC) at 250◦ C with two biochars produced from slow pyrolysis at 450◦ C and 650◦ C, respectively. The chars were also chemically modified with H2 SO4, H3 PO4, H2 O2, and KOH to investigate the potential for sorption enhancement. The highest sorption capacities for NH3 were observed for the hydrochars with typical uptake capacities ranging from 18–28 mg g−1 NH3. Sorption capacity for oak biochars is significantly lower and ranges from 4–8 mg g−1 for biochars produced at 450◦ C and 650◦ C, respectively. Hydrochar showed a substantially higher sorption capacity for NH3 despite its lower surface area. The CaCl2 extractable NH4+ following ammonia adsorption is incomplete. Typically, only 30–40% of the N is released upon washing with CaCl2 in form of NH4+. Post chemical modification of the chars resulted in only limited enhancement of char NH3 and NH4+ sorption. H3 PO4 treatment showed the greatest potential for increasing NH3 /NH4+ sorption in biochars, while KOH and H2 O2 treatment increased NH3 sorption in the hydrochar. As only marginal increases to char surface area were observed following char treatment, these findings suggest that char surface functionality is more influential than surface area in terms of char NH3 /NH4+ sorption.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional 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 (http://creativecommons.org/licenses/by/4.0/). |
Keywords: | hydrochar; biochar; activation; ammonia; ammonium; adsorption |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Funding Information: | Funder Grant number EU - European Union 289853 |
Depositing User: | Symplectic Publications |
Date Deposited: | 06 Feb 2019 16:27 |
Last Modified: | 06 Feb 2019 16:27 |
Status: | Published |
Publisher: | MDPI |
Identification Number: | 10.3390/agriculture9010016 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:142208 |