Abstract
This work focused on the effect of combustion on the yield, composition, and strength of food-grade bio- alkali from lignocellulosic agro-waste. Seven lignocellulosic types of agro-waste, including plantain stalk, plantain peel (green and ripe), empty palm bunch, palm fiber, coconut fiber, and cocoa pod were sun-dried and combusted using two methods: open-air combustion (OAC) and muffle furnace combustion (MFC). Ash and potash yield from the two methods of combustion were determined using simple proportion calculations. A two-stage hydrothermal extraction process was carried out on the ash using a deionized water ratio of 1:10 for food-grade bio-alkali, and the leachates were evaluated for pH, alkalinity, and metallic ion contents using standard analytical methods. The data obtained were statistically analyzed via a two-way ANOVA. The OAC samples had a higher ash content range (8.24–18.6%) compared to MFC samples (7.37–9.89%). Potash yield (%) is both biomass and combustion-method dependent, with MFC having a higher average yield (3.05%) than OAC (2.35%). The pH of the leachates for all samples ranged from 10.3 to 12.0. All the agro-waste exhibited a similar pattern in the order of magnitude of the metals of which they were composed (K > Mg > Ca > Zn > Na). For the minerals, PO4 was highest (193.1 g/L) in plantain stalk, and KOH and K2CO3 were least (10.0 g/L) in coconut fiber, while the highest alkalinity was obtained in ripe plantain peel (62.1 mg/L). The yield and quality of bio-alkali produced were influenced by the combustion method and source of biomass. The bio-alkali from the different biomass types tested can be used as sources of food-grade emulsifiers due to their high nature of alkalinity. This signifies zero waste and is also a boost to the circular economy. The average alkalinity studied under MFC was 33.6 mg/L and for OAC was 27.3 mg/L, suggesting that MFC is a more promising approach. Worthy of exploration is the significant high content (19.3 mg/L) of chlorine in plantain stalk.
Author Contributions
Conceptualization, U.O., D.O. and E.K.; methodology, U.O.; software, U.O. and D.O.; validation, U.O. and E.K.; formal analysis, U.O.; investigation, U.O. and E.K.; resources, TETfund; data curation, D.O. and E.K.; writing—original draft preparation, U.O.; writing—review and editing, D.O. and E.K.; visualization, U.O. and D.O.; supervision, U.O.; project administration, U.O.; funding acquisition, TETfund. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by TETfund, and the grant number is OVC/TETFUND/GEN/8.
Institutional Review Board Statement
Not applicable.
Informed Consent Statement
Not applicable.
Data Availability Statement
The data that support the findings of this study are available from the corresponding author, upon request.
Conflicts of Interest
The authors declare that have no known conflict of interest that could have appeared to influence the work reported in this paper and they adhered to all the guidelines of the journal. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |
© 2024 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 (https://creativecommons.org/licenses/by/4.0/).