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β-FeOOH/TiO2 Heterojunction for Visible Light-Driven Photocatalytic Inactivation of E. coliBy 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 QualityBy 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 MethodBy 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
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