Chapters authored
β-FeOOH/TiO2 Heterojunction for Visible Light-Driven Photocatalytic Inactivation of E. coli By Mahabubur Chowdhury, Ncumisa Mpongwana, Franscious
Cummings, Veruscha Fester and Seteno Ntwampe
In this work, we report on the photocatalytic properties of β-FeOOH/TiO2 heterojunction material for the inactivation of Escherischia coli. XRD, HRTEM, EELS, ELNEFS were used to characterize the as-prepared material. A log reduction of the initial bacterial population was achieved after 45 min of irradiation in the presence of 0.1 mL of hydrogen peroxide. The enhanced photocatalytic activity was due to the effective charge transfer between Ti4+, Fe3+, and O2+ as shown from the EELS analysis of the heterojunction structure. The role of various reactive species formed due to the photocatalytic reaction was also investigated. Presence of •OH radicals in the bulk solution was the key factor in the photocatalytic inactivation of E. coli.
Part of the book: Semiconductor Photocatalysis
Leaching of Cyanogens and Mycotoxins from Cultivated Cassava into Agricultural Soil: Effects on Groundwater Quality By Elie F. Itoba-Tombo, Seteno K.O. Ntwampe and John B.N. Mudumbi
Cyanogens and mycotoxins are vital in protecting flora against predation. Nevertheless, their increased concentrations and by-products in agricultural soil could result in produce contamination and decreased crop yield and soil productivity. When exposed to unsuitable weather conditions, agricultural produce such as cassava is susceptible to bacterial and fungal attack, culminating in spoilage, particularly in arid and semi-arid regions, and contributing to cyanogen and mycotoxins loading of the arable land. The movement of cyanogen including mycotoxins in such soil can result in sub-surface and/or groundwater contamination, thus deteriorating the soil’s environmental health and negatively affecting wildlife and humans. Persistent cyanogen and mycotoxins loading into agricultural soil changes its physico-chemical characteristics and biotic parameters. These contaminants and their biodegradation by-products can be dispersed from soil’s surface and sub-surface to groundwater systems by permeation and percolation through the upper soil layer into underground water reservoirs, which can result in their exposure to humans and wildlife. Thus, an assessment and monitoring of cyanogen and mycotoxins loading impacts on arable land and groundwater in communities with minimal resources should be done. Overall, these toxicants impacts on agricultural soil’s biotic community, affect soil’s aggregates, functionality and lead to the soil’s low productivity, cross-contamination of fresh agricultural produce.
Part of the book: Aflatoxin
Exploring Musa paradisiaca Peel Extract as a Green Corrosion Inhibitor for Mild Steel Using Factorial Design Method By Olusola S. Amodu, Moradeyo O. Odunlami, Joseph T. Akintola, Seteno K. Ntwampe and Seide M. Akoro
The suitability ofMusa paradisiaca (banana) peel extract as a green corrosion inhibitor for mild steel in acidic medium (1 M HCl) was investigated using factorial method of the design of experiment. The effects of two independent variables (concentration of banana peel extract and temperature) on the corrosion inhibition efficiency were investigated. The physicochemical properties of the extract such as surface tension, viscosity, flash point, and specific gravity were determined using standardized methods provided by the American System of Testing Materials (D-971). The relationship between the independent variables and the inhibitor efficiency was modeled by gasometric and thermometric methods. The statistical analysis of the inhibition efficiency was carried out using the “Fit Regression Model” of Minitab® 17.0, while the fitness of the models was assessed by the coefficient of determination (R2) and the analysis of variance (ANOVA). From the results obtained, gasometric method achieved a maximum inhibition efficiency of 66.83%, with an R2 of 90.76%, whereas thermometric method gave a maximum inhibition efficiency of 65.70%, with an R2 of 95.56%. This study shows that banana peel extract has the capacity to prevent the corrosion of mild steel in acidic medium.
Part of the book: Corrosion Inhibitors
Cunninghamella bertholletiae’s Toxins from Decomposing Cassava: Mitigation Strategy for Toxin Reduction Using Nepenthes mirabilis ‘Monkey Cup’ Digestive Fluids By Elie Fereche Itoba-Tombo, Seteno Karabo Obed Ntwampe, John Baptist Nzukizi Mudumbi, Lukhanyo Mekuto, Enoch Akinbiyi Akinpelu and Nkosikho Dlangamandla
A fermentation technique was utilised to assess a fungus, i.e. Cunninghamella bertholletiae/polymorpha, isolated from rotting cassava, ability to produce mycotoxins and resultant oxidation by-products of the mycotoxins using liquid chromatography–mass spectrometry (LC/MS). Thus, the mycotoxins/secondary metabolites, fumonisin B1 (FB1) and deoxynivalenol (DON) were produced while, heptadecanone, octadecanamide, octadecenal and 3-keto-deoxynivalenol (DON) were successfully identified as biodegradation by-products in the fermentation broth treated with hydrolysing ‘monkey cup’ juice from Nepenthes mirabilis. Exposure to the mycotoxins and the biodegradation by-products through consumption of contaminated produce including contact due to the cumulative presence in arable agricultural soil can be harmful to humans and animals. Therefore, this work reports on a strategy for the mitigation and reduction of mycotoxins in agricultural soil using natural plant pitcher juices from N. mirabilis’ ‘monkey cup’.
Part of the book: Mycotoxins and Food Safety
Medicinal Plants Threatened by Undocumented Emerging Pollutants: The Sub-Saharan African Viewpoint By John Baptist Nzukizi Mudumbi, Elie Fereche Itoba-Tombo, Seteno Karabo Obed Ntwampe and Tandi Matsha
The history of medicinal plants on the African continent is huge, the oldest and probably the most diverse, for there are thousands of spoken languages, in the sub-Saharan African region, that are used during the traditional practices that utilize medicinal plants for healing purposes. However, our lines of research have exhibited a potential unprecedented threat to this remarkable history of African medicinal plants by emerging pollutants, the per- and polyfluoroalkyl substances (PFASs), which are yet to be efficiently and sufficiently reported and documented on in this region. Accordingly, this review chapter reports on sub-Saharan African medicinal plants with the aim of highlighting how undocumented PFASs, in this region, present a huge threat to the extraordinary diversity of these plants and the therapy that they have assisted the low-income populations of this region with for centuries. Thus, we recommend appropriate and regular assessments and monitoring of PFASs, particularly perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) the most studied of these substances and their substitutes, in medicinal plants of the region, for these chemicals have been scientifically proven to be associated to numerous health concerns. The region should also consider properly regulating these compounds.
Part of the book: Medicinal Plants
View all chapters