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Facile Preparation of Cross-Linked Moringa oleifera Seed Hulls Powder/ Hydroxyapatite Framework Composite for Efficient Removal of Toluidine Blue and Methyl Violet 2B from Aqueous Solution
Get PDFJournal Article, Materials Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Natural and Agricultural
Science, North-West University, (Mafikeng Campus)In this study, adsorption of two cationic dyes, Toluidine Blue (TB) and Methyl violet 2B (MV 2B) from an aqueous solution was achieved by using multifunctional composite material. The formulation of the composite (MO@HA) was obtained by using Moringa oleifera seed hull powder, calcium chloride (CaCl2), and ammonium hydrogenophosphate (NH4)2HPO4 salts. Surface morphology, functional groups, specific surface area, and surface charge of the composite were explored using Scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FTIR), BET analysis, and point of zero charge (PZC), respectively. The composite material resulted in a structural change in the surface of the adsorbents, increased oxygen vacancies, enhancement of active sites, and a specific surface area of 735.55 m2 g−1. Different adsorption parameters such as pH, contact time, adsorbent dosage, and initial concentration were evaluated. The adsorption study showed that equilibrium was reached after 60 min, and the optimum adsorption pH for both dyes (TB and MV 2B) was 6. Langmuir, Freundlich, Liu, and Temkin were fitted to describe the adsorption isotherm, both TB and MV 2B had best correlation with Liu isotherm. The maximum adsorption capacity of TB and MV 2B were 341.488 and 182.453 mg g−1, respectively. Adsorption-desorption cycling studies on the adsorbent confirmed its regeneration and reusability after 5 cycles. A possible adsorption mechanism involving electrostatic interactions, n-π bonding, and hydrogen bonding was suggested. These findings highlight a new direction in the development of efficient and sustainable adsorbent in environmental remediation, specifically in the removal of dyes from aqueous solution.Open access funding provided by North-West Universit
Spatio-spectral-temporal modelling of two young pulsar wind nebulae
No full textArticle, Faculty of Natural and Agricultural Sciences (Centre for Space Research (CSR)--Northwest University, Potchefstroom CampusRecent observations of a few young pulsar wind nebulae (PWNe) have revealed their morphologies in some detail. Given the availability of spatio-spectral-temporal data, we use our multi-zone (1D) leptonic emission code to model the PWNe associated with G29.7−0.3 (Kes 75) and G21.5−0.9 (G21.5), and obtain (by-eye) constraints on additional model parameters compared to spectral-only modelling. Kes 75 is a Galactic composite supernova remnant (SNR) with an embedded pulsar, PSR J1846−0258. X-ray studies reveal rapid expansion of Kes 75 over the past two decades. PWN G21.5 is also a composite SNR, powered by PSR J1833−1034. For Kes 75, we study a sudden plasma bulk speed increase that may be due to the magnetar-like outbursts of the central pulsar. An increase of a few per cent in this speed does not result in any significant change in the model outputs. For G21.5, we investigate different diffusion coefficients and pulsar spin-down braking indices. We can reproduce the broad-band spectra and X-ray surface brightness profiles for both PWNe, and the expansion rate, flux over different epochs, and X-ray photon index versus epoch and central radius for Kes 75 quite well. The latter three features are also investigated for G21.5. Despite obtaining reasonable fits overall, some discrepancies remain, pointing to further model revision. We find similar values to overlapping parameters between our 1D code and those of an independent 0D dynamical code (TIDE). Future work will incorporate spatial data from various energy wavebands to improve model constraints
Nanoparticle applications in agriculture: overview and response of plant-associated microorganisms
Get PDFJournal. Article. Unit of Environmental Sciences and Management, North-West University, PotchefstroomGlobally, food security has become a critical concern due to the rise in human population and the current climate change crisis. Usage of conventional agrochemicals to maximize crop yields has resulted in the degradation of fertile soil, environmental pollution as well as human and agroecosystem health risks. Nanotechnology in agriculture is a fast-emerging and new area of research explored to improve crop productivity and nutrient-use efficiency usingnano-sized agrochemicals at lower doses than conventional agrochemicals. Nanoparticles in agriculture are applied as nanofertilizers and/or nanopesticides. Positive results have been observed in terms of plant growth when using nano-based agricultural amendments. However, their continuous application may have adverse effects on plant-associated rhizospheric and endospheric microorganisms which often play a crucial role in plant growth, nutrient uptake, and disease prevention. While research shows that the application of
nanoparticles has the potential to improve plant growth and yield, their effect on the diversity and function of plant-associated microorganisms remains underexplored. This review provides an overview of plant-associated microorganismsand their functions. Additionally, it highlights the response of plant-associated microorganisms to nanoparticle application and provides insight into areas of research required to promote sustainable and precision agricultural practices
that incorporate nanofertilizers and nanopesticides
Influence of a binary phase ZnO–CuO on the structural and reflectance properties of poly-ε-caprolactone based nanocomposites
Get PDFDepartment of Physical and Chemical Sciences, North-West University (Mafikeng Campus), South AfricaThe binary phase metal oxide of ZnO and CuO (BPMO-ZC) nanopowders were synthesized by the chemical bath
deposition. The BPMO-ZC nanopowders were distributed through the poly-ε-caprolactone (PCL) matrix by solution casting. The effect of the BPMO-ZC on the structure, thermal and reflectance properties of PCL was
investigated. The X-ray diffraction (XRD) confirmed the combined hexagonal wurtzite and cubic forms of the
respective ZnO and CuO nanomaterials as well as an orthorhombic form of the semi-crystalline PCL nanocomposite films. Morphology included aggregated particles with heterogeneous distribution. Differential scanning calorimetry (DSC) showed that the degree of crystallinity of nanocomposites films increased in the presence
of the nanopowders. Nanocomposites displayed poor thermal stability compared to PCL, but improved residue.
Reflectance measurement revealed that the absorption edges of PCL shifted to higher wavelength with the
addition of ZnO–CuO
Electro-oxidation of pyrene on glassy carbon electrode modified with fMWCNTs/CuO nanocomposite
Get PDFJournal Article, Department of Chemistry, Faculty of Natural and Agricultural Sciences, North-West University (Mafikeng Campus)The electrochemical oxidation of pyrene, a well-known polycyclic aromatic hydrocarbon, was investigated using a glassy carbon electrode (GCE) modified with nanocomposite of copper oxide nanoparticles incorporated functionalized multi-walled carbon nanotubes (fMWCNTs). The catalytic copper oxide nanoparticles (CuONPs) synthesized through a chemical co-precipitation method was combined with the highly electrically conductive functionalized multi-walled carbon nanotubes using a simple and efficient method. Several analytical techniques were employed in characterizing the nanomaterials namely: the scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDS), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD), and the ultraviolet–visible (UV–vis) spectroscopy, to validate the authenticity of the synthesis. The electrochemical behaviour of the proposed electrode was investigated in 10 mM [Fe(CN)6]3-/4- via electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), revealing the highest current response and lowest charge transfer resistance at the hybrid nanocomposite modified electrode (GCE/fMWCNTs/CuO NPs) in comparison with the other electrodes studied in this work (GCE, GCE/CuO NPs, and GCE/fMWCNTs. The electrocatalytic efficacy of the electrodes towards pyrene oxidation was also evaluated, with a similarly outstanding increment in the oxidation peak current response and highly reduced resistance to charge transfer at the nanocomposite-modified glassy carbon electrode. This enhanced electrocatalytic activity facilitated the transport of electrons between the pyrene molecules and the nanocomposite-modified electrode which is attributable to the synergy between the functionalized multi-walled carbon nanotubes and the copper oxide nanoparticles. The low detection limit of 1.30 μM within the linear range (1.2–23.1 μM) demonstrated by the sensor indicates its high sensitivity and potential for environmental based analytical applications such as pyrene detection
The Management and Preservation of Indigenous Knowledge at Kwa-Khaya Lendaba cultural village in Gauteng Province, South Africa.
Get PDFMaster of Indigenous Knowledge Systems, North-West University, MafikengFor many years, cultural villages have existed in Africa, primarily for tourist attraction and economic benefit. Many cultural villages deteriorate due to human activities, and these cultural villages, as well as the indigenous knowledge found in these cultural villages, are not adequately protected by the indigenous people. Indigenous knowledge has been recognized for its pivotal role as a strategic tool in the development of the lives of people in the world. Indigenous knowledge (IK) management and preservation are critical in academia. This thesis aimed to explore and document the indigenous knowledge and practices and knowledge management methods and tools used to preserve and manage IK at Kwa-Khaya Lendaba cultural village because this knowledge is lost due to oral transmission, lack of documentation, and the deterioration of his cultural villages. The data was generated using face-to-face, in-depth interviews, focus group discussions, and the Knowledge Attitude and Perception (KAP) Likert scale, to know about the perception of the local people regarding IK, Cultural Villages, and knowledge management of IK in cultural villages. The data generated was analysed using thematic analysis to identify the IK practiced in the cultural villages and the knowledge management approaches that should be used to preserve and manage IK in the cultural villages and statistical package for the social sciences (SPSS) was used for quantitative data, to get descriptive data, to calculate and get percentages. The study's findings revealed that cultural villages play a vital role in the community and that cultural villages depict diverse cultures. However, the knowledge behind the Cultural Villages is not documented, preserved, and managed. IK Activities that practiced at KKL cultural village demonstrated that there is a need to preserve and disseminate information to the local people. As a result, there is a need to document and disseminate this knowledge to local people, particularly to the youth, in schools. The communities need to be educated about the advantages of using knowledge management tools for preserving and managing their knowledge. It has been concluded that the extent to which` IK is preserved in the cultural villages is poor and the best way to preserve, disseminate, and share indigenous knowledge by using Information and Communication Technology and libraries. The study's goal was to document Indigenous Knowledge found in Kwa-Khaya Lendaba cultural village and to investigate various methods for preserving and managing IK. This is the first study conducted on IK at Kwa-Khaya Lendaba cultural village. Therefore, this research study contributes to the advancement of knowledge on IK within the
context of cultural villages. The study further contributes to new insight of the role that tourism can play in the preservation of IK, of which is often overlooked in scientific researc
Slow Pyrolysis Products Derived from Extrudates Produced from Discard Coal Fines and Recycled Plastics as Binders
Get PDFJournal Article. Centre of Excellence in Carbon-Based Fuels, North-West University, Potchefstroom CampusThe pyrolysis products derived from both coal and plastics have been extensively evaluated in literature; however, their copyrolysis product yields together with the characterization of the generated products have received less attention. Most studies use high heating rates with small particle sizes of the mechanically mixed blends. This study aims to improve the understanding of the slow copyrolysis behavior of extrudates produced from coal fines from the South African Highveld coalfield combined with recycled waste low-density polyethylene (LDPE) and polypropylene (PP). The fraction of plastic was varied between 10 and 100 wt % during extrusion. The extrudates (10 mm diameter) underwent slow pyrolysis in a modified Fischer assay setup by increasing the temperature (5 °C/min) under a nitrogen atmosphere to 520, 720, and 920 °C. The pyrolysis products (char, condensable products, water, and gas) were collected and characterized. The coal fines produced up to 83% char, whereas the plastics produced over 90% condensable products. The slow heating rate and the small reactor volume favored the production of condensable products, which increased with plastic concentration. The extrudates produced char and condensable product yields that fit the additive model of the raw materials. Statistical equations were developed to predict the pyrolysis yields and characteristics as functions of coal and plastic composition. The equations accurately predict the char yield, condensable product yield, fixed carbon content, ash content, sulfur content of chars, and carbon and hydrogen contents of chars and condensable products. Gas chromatography–mass spectrometry results indicate that the extrudates’ condensable products consist mainly of alkanes and alkenes, similar to the plastics. Furthermore, the condensable products derived from PP and coal extrudates have fewer components with lower boiling points compared with the raw materials
Unravelling the toxicity of carbon nanomaterials – From cellular interactions to mechanistic understanding
No full textJournal Article, Unit for Environmental Sciences and Management, North-West University, Potchefstroom CampusThe application of carbon nanomaterials in diverse fields has substantially increased their demand for commercial usage. Within the earliest decade, the development of functional materials has further increased the significance of this element. Despite the advancements recorded, the potential harmful impacts of embracing carbon nanomaterials for biological applications must be balanced against their advantages. Interestingly, many studies have neglected the intriguing and dynamic cellular interaction of carbon nanomaterials and the mechanistic understanding of their property-driven behaviour, even though common toxicity profiles have been reported. Reiterating the toxicity issue, several researchers conclude that these materials have minimal toxicity and may be safe for contact with biological systems at certain dosages. Here, we aim to provide a report on the significance of some of the properties that influence their toxicity. After that, a description of the implication of nanotoxicology in humans and living systems, revealing piece by piece their exposure routes and possible risks, will be provided. Then, an extensive discussion of the mechanistic puzzle modulating the interface between various human cellular systems and carbon nanomaterials such as carbon nanotubes, carbon dots, graphene, fullerenes, and nanodiamonds will follow. Finally, this review also sheds light on the organization that handles the risk associated with nanomaterials
Social support and well-being of adolescent learners: a latent profile analysis
Get PDFNorth-West UniversityThis study focused on identifying adolescent learners’ social support profiles based on their selfreports regarding three sources of social support (parental, teacher, and close friend support)
and associations of such profiles with their well-being. A biographical questionnaire, the Social
Support Scale for Children, and the Mental Health Continuum – Short Form were administered
to 770 Grades 10 and 11 learners from previously disadvantaged schools in South Africa.
Five social support profiles were identified using latent profile analyses of parental, teacher,
and close friend support: weakly supported, adult-supported, peer-supported, moderately
supported, and integrated support. Social support profiles were associated with well-being.
Flourishing, the most desirable well-being outcome, was associated with the integrated support
profile (high parent, teacher, and close friend support). In contrast, the lowest level of wellbeing was observed in the weakly supported profile (low parent, teacher, and close friend
support). The results confirmed that support from parents, teachers, and close friends was vital
for adolescent learners’ well-being
Evaluation of reliability generalization of Conner-Davison Resilience Scale (CD-RISC-10 and CD-RISC-25): A Meta-analysis
No full textJournal Article.Faculty of Humanities, North-West University, PotchefstroomBackground
Resilience, a critical multi-faceted construct in psychological research, is often measured using Conner-Davison Resilience Scale (CD-RISC-10 and CD-RISC-25). This reliability generalization (RG) meta-analysis delves into evaluate the level of reliability generalization estimate of both CD-RISC-10 and CD-RISC-25 in assessing resilience across diverse populations and settings.
Methods
A reliability generalization meta-analysis on the psychometric properties of CD-RISC-10 and CD-RISC-25 was conducted, encompassing 27 studies. The original versions’ psychometric properties were systematically retrieved from databases including PubMed, PsycINFO, Google Scholar, Web of Science, Science Direct, and Scopus, with a focus on studies published between 2018 and 2023. The study protocol, including the specific methods for the reliability generalization meta-analysis, was pre-registered in the Prospero database (registration number CRD42023479052). This pre-registration ensures transparency and minimizes the risk of bias in the study design and analysis.
Results
The analysis revealed a combined estimated overall estimate of Cronbach’s Alpha of 0.89 (95% CI [0.87, 0.91], z = 77.20, p < 0.05), indicating a high level of reliability for CD-RISC-10 and CD-RISC-25. CD-RISC-10 exhibited an overall estimate of Cronbach’s Alpha of 0.8732 (95% CI [0.85, 0.10], z = 69.81, p < 0.05), indicating a high level of reliability, while CDRISC- 25 also demonstrated an overall estimate of Cronbach’s Alpha of 0.8922 (95% CI [0.87, 0.91], z = 77.20, p < 0.001), indicating a high level of reliability. Furthermore, CDRISC- 10 displayed commendable reliability (ωα+ = 0.86), slightly lower compared to the
impressive reliability of CD-RISC-25 (ωα+ = 0.89), with a significant difference (t = 0.1159, p > 0.001). The mixed-effects model revealed a non-significant moderating effect of the CDRISC language version on reliability estimates (coefficient = -0.0017, p <0.05).
Conclusion
The results affirm the high overall reliability of both CD-RISC-10 and CD-RISC-25, with CD-RISC-25 exhibiting a slightly superior level. The non-significant moderating effect of language version suggests that the psychometric properties of these scales remain robust across different linguistic adaptations. These findings enhance our understanding of the CD-RISC scales, providing practitioners, researchers, and clinicians valuable insights for informed scale selection in diverse contexts. The commendable reliability of both scales underscores their utility in assessing and promoting resilience across varied populations and settings. Future research should explore specific contexts, demographics, and applications, enhancing their utility for diverse populations and settings