Browsing by Author "Machunda, Revocatus L."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Biomass-based carbon electrode materials for capacitive deionization: a review
    (Springer, 2019-06-27) Elisadiki, Joyce; Kibona, Talam Enock; Machunda, Revocatus L.; Saleem, Muhammad Wajid; Kim, Woo-Seung; Jande, Yusufu A. C.
    Capacitive deionization (CDI) is a promising water purification technology which works by removing salt ions or charged species from aqueous solutions. Currently, most of the research on CDI focuses on the desalination of water with low or moderate salt concentration due to the low salt adsorption capacity of the electrodes. The electrosorption capacity of CDI relies on the structural and textural characteristics of the electrode materials. The cost of electrode materials, the complicated synthesis methods, and the environmental concerns arising from material synthesis steps hinder the development of large-scale CDI units. By considering the good electrical conductivity, high specific surface area (SSA), porous structure, availability, mass production, and cost, porous carbon derived from biomass materials may be a promising CDI electrode material. This review presents an update on carbon nanomaterials derived from various biomasses for CDI electrodes. It covers different synthesis methods and the electrosorption performance of each material and discusses the impact of the SSA and porous structure of the materials on desalination. This review shows that a variety of biomass materials can be used to synthesize cost-effective CDI electrode materials with different structures and good desalination performance. It also shows that diverse precursors and synthesis routes have significant influences on the properties and performance of the resulting carbon electrodes. Additionally, the performance of CDI does not depend only on BET surface area and pore structure but also on the applied voltage, initial concentration of the feed solution, and mass, as well as the capacitance of the electrodes.
  • Thumbnail Image
    Item
    A Molecular Investigation of the Solvent Influence on Inter- and Intra-Molecular Hydrogen Bond Interaction of Linamarin
    (MDPI, 2022-02-11) Paul, Lucas; Deogratias, Geradius; Shadrack, Daniel M.; Celestin N., Mudogo; Mtei, Kelvin M.; Machunda, Revocatus L.; Paluch, Andrew S.; Ntie-Kang, Fidele
    Linamarin has been reported to have anticancer activities; however, its extraction and isolation using different solvents yield a low amount. Therefore, understanding the physical properties, such as solvents’ solubility, membrane permeability and lipophilicity and how they are associated with different solvents, is a paramount topic for discussion, especially for its potential as a drug. Linamarin has a sugar moiety with many polar groups responsible for its physical properties. Following current trends, a molecular dynamics simulation is performed to investigate its physical properties and how different solvents, such as water, methanol (MeOH), dimethyl sulfoxide (DMSO) and dichloromethane (DCM), affect such properties. In this work, we have investigated the influence of intermolecular and intramolecular hydrogen bonding and the influence of polar and non-polar solvents on the physical properties of linamarin. Furthermore, solvation free-energy and electronic structure analysis are performed. The structural analysis results show that the polar groups of linamarin have strong interactions with all solvents except the etheric oxygen groups. A detailed analysis shows intermolecular hydrogen bonding between polar solvents (water, MeOH and DMSO) and the hydroxyl oxygens of linamarin. Water exhibits the strongest interaction with linamarin’s functional groups among the investigated solvents. The findings show that within the first solvation shell, the number of water molecules is greatest, while MeOH has the fewest. Centrally to the structural analysis, solvation free energy confirms DMSO to be the best solvent since it prefers to interact with linamarin over itself, while water prefers to interact with itself. While the solute–solvent interactions are strongest between linamarin and water, the solvent–solvent interactions are strongest in water. As a result, the solvation free-energy calculations reveal that linamarin solvation is most favourable in DMSO.