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Development of photocatalytic ceramic membrane for the removal of pharmaceuticals from water
(North-West University (South Africa), 2025) Sawunyama, Lawrence
The use of advanced hybrid wastewater treatment techniques in the elimination of emerging contaminants such as pharmaceuticals has recently attracted significant interest as a viable technique for industrial scale wastewater treatment. Advanced hybrid wastewater treatment techniques are based on the integration of different advanced wastewater treatment techniques such as membrane technology, advanced oxidation processes and bioremediation. Each approach addresses different aspects of contaminants removal, resulting in a robust system that enhances efficiency by minimizing the drawbacks of individual technique and enhancing their advantages. The aim of this study was to prepare a hybrid wastewater treatment technique involving photocatalysis and ceramic membrane technology and evaluate their efficiency in the removal of tetracycline as a model wastewater pollutant by utilising both photocatalysis and filtration processes. The main technical barriers hindering the application of photocatalysis at industrial scale are: (1) limited utilization of solar spectrum by most photocatalysts; (2) high electron and hole recombination rate, which lowers quantum efficiency and photocatalytic activity; (3) poor adsorption towards non-polar organic pollutants; (4) challenging recovery of the used nanoparticles from the uniform suspension; and (5) low thermal stability. Therefore, this work focused on the fabrication of surface defective heterojunction nanocomposites from TiO2 and ZnO in order to enhance the photocatalytic activity through improved light absorption capabilities and charge separation process. High energy requirements for sintering, high cost of starting materials, and limited effectiveness in pollutant mineralization are identified as significant drawbacks in the industrial application of ceramic membrane technology. Therefore, this study focussed on fabrication of affordable and sustainable ceramic membranes from coal fly ash, an industrial solid waste product, and natural sand, a commonly available and inexpensive natural material. Firstly, surface defective TiO2-ZnO heterojunction nanocomposite were synthesized using the conventional sol-gel approach, coupled with aluminium foil-assisted NaBH4 reduction. Titanium tetra-isopropoxide and zinc acetate were used as precursors at different molar ratios while isopropyl alcohol and water were used as solvents. Subsequently, ceramic membranes were fabricated by the uniaxial compaction of the starting material (coal fly ash, natural sand, dextrin (pore former) and carboxymethyl cellulose (binder)) using a manual hydraulic pressing machine. The coal fly ash and natural sand were mixed in different proportions and the fabricated ceramic membranes were sintered at different temperatures of 800, 100, and 1200 ℃. Finally, the novel TiO2-ZnO functionalized coal fly ash-based ceramic membrane was fabricated utilizing co-pressing and co-sintering processes. The photoactive layer was formed by placing the grounded mixture of pre weighed photocatalyst (TiO2-ZnO) and pre-weighed ceramic membrane precursor material on the mold's base, and the supporting layer was formed by adding pre-weighed ceramic membrane precursor material to the mold. The structure, morphology, surface properties, and optical characteristics of the synthesized materials were studied using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-vis absorption spectra, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), Thermogravimetric analysis (TGA) and Transmission electron microscopy (TEM). The viii properties of the optimized membranes were further studied to ascertain their mechanical strength, chemical stability, porosity, water absorption, water permeability, and shrinkage behaviour. The XRD analysis confirmed the successful formation of black BTiO2-ZnO heterostructure, while SEM revealed the structural morphology as pseudo-spherical with slight agglomeration. BTiO2-ZnO was found to be more efficient than BTiO2 and BZnO for the removal of tetracycline with degradation efficiencies of 63, 58, and 56 % respectively. The effects of process parameters such as the amount of photocatalyst, pollutant's concentration, and the initial solution pH on photocatalytic degradation study were systematically explored. The results confirm that the formation of the heterostructure from BTiO2 and BZnO could offer a facile route to improving the catalytic degradation of tetracycline. X-ray fluorescence (XRF) analysis of the starting materials (coal fly ash and natural sand) confirmed the presence of SiO2 and Al2O3, two key inorganic materials required for the fabrication of ceramic membranes. ICP OES analysis revealed that coal fly ash contains heavy metals, including arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and mercury (Hg). The levels of arsenic and chromium exceeded the WHO limits. Therefore, the heavy metals present in the raw coal fly ash were successfully leached out using acetic acid prior to the fabrication process. The membrane fabricated with 20 wt% sand content and at 1000 °C sintering temperature had pore size of 0.64 µm and 34.7% porosity, exhibited good mechanical strength (7.71 MPa), and exceptional chemical stability. The membrane also showed a remarkable water permeability of 32.23 L/m2 /h. The ceramic membrane functionalized with 0.5 g of TiO2 -ZnO and sintered at 850 °C exhibited good thermal, chemical stability, and porosity required for ultrafiltration applications. The optimum photocatalytic efficiency of the functionalized photocatalytic substrate achieved within 100 min under the visible light was estimated at 77% and removal efficiency by filtration was estimated at 57%. Moreover, the functionalized membrane was found to be stable with 73% photocatalytic degradation efficiency after 5 consecutive cycles of reusability test, with negligible loss of efficiency. In the filtration studies, tetracycline was simply adsorbed and filtered without degradation complicating desorption from surface-active areas. The scale-up of photocatalytic ceramic membranes and their utilization in real industrial applications will confirm their robustness when used in a hybrid photocatalysis and filtration reactor system that optimize its synergistic photocatalytic, adsorption, and filtration properties. In general, the use of advanced hybrid wastewater treatment techniques, specifically through the use of photocatalytic ceramic membranes fabricated from cost-effective starting materials, presents a promising and sustainable alternative for the removal of pharmaceuticals from water.
Project risk culture in a South African state-owned entity
(North-West University (South Africa), 2020) Nemukula, Fhulufhedzani Irene
The concept of risk culture came to the fore after the 2007/08 financial crisis, when it was identified as a leading contributor to instability in the financial industry. The available literature on risk culture tends to focus on the financial sector, with few risk-culture-specific articles published on non???financial institutions such as public organisations; and none could be found on project risk culture in South African state-owned entities (SOEs). The objective of this study was to explore the perceptions of project team members of aspects related to project risk management in a South African SOE, using a risk culture indicator (RCI) model to structure the research. The research question for this study was therefore: "How do project team members perceive project risk culture in this SOE?" Semi-structured face-to-face interviews were conducted with a sample of 15 participants whose roles require project implementation decision-making in the organisation. The results of the study indicated that project team members rely on experience and information from a panel of experts and consultants in order to include project risks when making project-related decisions. Interviewees suggested that the entity's project risk management process should be improved to ensure that the risk-related information documented, as a result of the internal risk management process, is relevant and of quality to assist with project decision-making. Four indicators - risk-based incentives, communication, challenge and risk accountability - did not feature in the participants' responses, and attention to these indicators may also assist with improving the entity's project risk culture. Overall, this study contributes to the understanding of the perceived project risk culture within the organisation and exemplifies a novel research approach for other researchers interested in conducting project risk culture studies.
The impact of COVID-19 on remuneration structures of South African JSE-listed transportation companies
(Bussecon International (Published in International Journal of Business Ecosystem & Strategy, Vol. 7, No. 5, pp. 375–384), 2025) Mandie,Adriaanse; de Villiers, Rikus R.; Kilian, Elsabé
This study examines how COVID-19 affected executive remuneration in South African transportation firms on the JSE and changes in intangible employee benefits. Utilizing a mainly quantitative approach, it evaluates post-pandemic remuneration data for structural changes, supplemented by qualitative analysis of corporate disclosures on intangible benefits. Findings show a shift towards variable compensation like bonuses and incentives, with reduced base salaries. Companies have also shown more concern for employee well-being, adopting flexible working arrangements and prioritizing health and safety. The pandemic prompted significant structural and philosophical changes in remuneration practices. The study contributes to the existing body of knowledge by offering a sector-specific analysis of how global disruptions can reshape compensation frameworks, thereby informing future corporate governance and human resource strategies.
Relationship among intrinsic rewards, organisational performance, and intentions to stay among academic staff in a selected South African higher education institution
(Taylor & Francis, 2026) Makwela, Clement; Klinck, Kezell
This study examines the relationship among intrinsic rewards, organisational performance and academic staff intentions to stay at a selected South African higher education institution. A quantitative research design and descriptive research approach were adopted. Data were collected from 400 permanent academic staff using a structured questionnaire and analysed using IBM SPSS and IBM SPSS-AMOS (version 31), applying descriptive statistics, reliability tests, correlation analysis, confirmatory factor analysis (CFA), and structural equation modelling (SEM). The findings reveal that intrinsic rewards have a significant positive influence on both academic staff intentions to stay and organisational performance. In addition, intentions to stay significantly influence organisational performance. The study contributes to the limited empirical literature on intrinsic rewards, retention intentions, and organisational performance within the South African higher education context.
Exploring the role of internal risk communication in decision-making within a food and beverages organisation
(North-West University (South Africa), 2026) Mzizi, Phendulwa; Magau, Rudzani; Mulambya, Emmanuel
Risk communication is important for effective risk management; it is a vital component of risk analysis.Risk communication and decision-making are connected, as effective risk communication enables risk informed decisions. This study aims to explore how internal risk communication informs decision-making in a food and beverages organisation in South Africa. The study was conducted within a multinational food and beverages organisation, with offices in South Africa. The study was conducted using an exploratory interview-based qualitative research approach and the researcher conducted semi-structured interviews where 10 employees were selected.The results extracted from interviews are organised into six themes: Internal risk communication; risk communication channels; benefits, risks, challenges, and strategies for effective risk communication.The findings indicated that the participants have an understanding and can define risk communication.Additionally, the results suggested a number of positive themes relating to how internal risk communication informs decision-making.However, the majority of the participants interviewed experienced challenges to how risk communication is transmitted.This study provides useful information on and a review of risk communications that can be used by the employees in the organisation.The research objectives were achieved, the results answered the research questions, and the recommendations were also made specifically for the risk communication challenges identified.The research scope was limited to internal risk ccommunication, and further research should be conducted to source the views of employees on other levels and in other departments.