Research Articles (Chemistry)
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This collection contains some of the full text peer-reviewed/ refereed articles published by researchers from the Department of Chemistry
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Item Investigation of Ximenia afra Sond. var. afra L. as a source of antiplasmodial and trypanocidal phytochemicals through accelerated bioactivity guided isolation(Elsevier, 2025-11) Rudolph, Wiehan; Webster, Lauren; Graebin, Cedric; Maharaj, Vinesh J.ETHNOPHARMACOLOGICAL RELEVANCE : Ximenia afra has been shown to be a potential source for antiprotozoal lead compounds based on its tentatively assigned phytochemistry or purely based on ethnomedicinal applications, where infusions of root, stem, and leaf mixtures, are often used for treating a wide range of parasitic ailments, including malaria and human African trypanosomiasis (HAT). Previous phytochemical analyses of extracts from the leaves showed high abundances of flavonoids and proanthocyanidins, and exhibited moderate to good activity against infections of Plasmodium sp. AIM OF THE STUDY : This study was designed to (i) Rapidly determine the bioactivity of the extract and seven corresponding fractions, from the crude extract of X. afra leaves and twigs, against both P. falciparum and Trypanosoma brucei; (ii) isolate and characterise the bioactive compound from these fractions; (iii) confirm the bioactivity of the isolated compound against P. falciparum and T. b. brucei. MATERIALS AND METHODS : An extract and fractions were produced from the mixed stems and leaves of X. afra. A set of seven polarity-based fractions were produced from the extract and evaluated in an in vitro phenotypic screen against single strains of bloodstream form P. falciparum (3D7) and T. b. brucei (Lister strain 427). High resolution mass spectrometry analysis was done on the bioactive fractions, to tentatively identify the constituents. Guided by these phytochemical profiles and the antiprotozoal activity of the fractions, a single compound was selected for targeted isolation. Quercitrin was isolated by semi-preparative high performance liquid chromatography (HPLC) and fully characterised by accurate mass analysis and nuclear magnetic resonance spectroscopy (NMR). Biological assays were done to determine the antiplasmodial and trypanocidal activities of quercitrin. RESULTS : In vitro phenotypic screening of the extract and fractions showed the mid-polar fractions exhibited significant antiplasmodial and trypanocidal activity. Tentative chemical profiling showed one of the highly bioactive fractions contained one major compound, which was then isolated. Accurate mass and NMR analyses confirmed the structure of the isolated compound as quercitrin. It was found to be active against P. falciparum (3D7), with IC50 = 2.76 μM (n = 2). However, the activity of the compound was poor against T. b. brucei (strain 427) (19 % inhibition at 25 μM; n = 1) and showed no inhibitory activity in the P. falciparum lysyl tRNAse synthetase (PfKRS1) assay. CONCLUSION : Further scientific evidence for the effectiveness of X. afra, in the treatment of malaria and HAT, was obtained. Quercitrin, for the first time, was isolated from the leaves and stems of X. afra and its activity against P. falciparum (3D7) was confirmed in vitro by phenotypic assay. Its activity against this strain was, until now, unknown. Although quercitrin alone was not a potent trypanocidal compound, the combination of it with other flavonoids and proanthocyanidins provided good activity (%-inhibition > 80 %).Item Recent advances in MXene-based nanocomposites for photocatalytic wastewater treatment, carbon dioxide reduction, and hydrogen production : a comprehensive review(Elsevier, 2026-02) Masekela, Daniel; Mafa, Potlako J.; Yusuf, Tunde Lewis; Balogun, Sheriff Aweda; Kuvarega, Alex Tawanda; Modibane, Kwena DesmondPlease read abstract in the article.Item Isolation, characterization, antioxidant and anticancer activities of compounds from Erythrina caffra stem bark extract(MDPI, 2025-09) Olawale, Femi; Bodede, Olusola; Ariatti, Mario; Singh, MoganavelliErythrina caffra is a traditional plant used to treat cancer and inflammation. The study aimed to assess and isolate anticancer compounds from E. caffra bark. The plant material was extracted sequentially in n-hexane, dichloromethane, ethyl acetate and methanol. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and 3-(4,5-di methyl thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were used to evaluate the crude extracts’ antioxidant and anticancer activities, respectively. Column chromatography was used to purify the potent extracts of the stem bark in order to isolate the bioactive compounds. The crude extracts of the E. caffra bark demonstrated antioxidant and anticancer activity, with the dichloromethane (DCM) extract producing the most favorable activity. Three compounds, namely Hexacosanyl isoferulate, Tetradecyl isoferulate, and 1-Heneicosanol, were detected in fractions from the DCM extract. All the isolated compounds showed significant anticancer potential, with the hydroxycinnamic acid compounds showing better anticancer effects in the cervical (HeLa) and breast cancer (MCF-7) cells. The compounds showed greater activity than even the standard drug, 5-fluorouracil, in the MCF-7 cells, with the tetradecyl isoferulate and hexacosanyl isoferulate fractions having IC50 values of 123.62 and 58.84 µg/mL, respectively. The compounds were observed to be capable of triggering caspase cascade events, leading to apoptotic cell death. Overall, E. caffra extracts contained important bioactive compounds that induced apoptotic cell death in HeLa and MCF-7 tumor cells, warranting further investigations in vitro and in vivo.Item Recent advances in metal/metal-oxide nanoparticle-polymer nanohybrid for biomedical applications(Elsevier, 2025-10) Bamisaye, Abayomi; Adekola, Monsuru Adewale; Abati, Shakirudeen Modupe; Etafo, N.O.; Ademola, Okewole Samson; Joseph, Philips Tosin; Samuel, Oreniyi; Ogunlaja, Olumuyiwa O.; Langmi, Henrietta Wakuna; Idowu, Mopelola Abidemi; abayomi.bamisaye@up.ac.zaAn increase in the application of metal/metal-oxide nanoparticle–polymer hybrid systems for biochemical purposes is due to their highly tunable porosity, large surface area and wide range of functional properties. These advanced materials exhibit exceptional biocompatibility, antibacterial properties, and controlled drug release characteristics, making them highly suitable for drug delivery, medical imaging, biosensing, and tissue engineering. The incorporation of metals and metal-oxide nanoparticles into the polymer matrix enhances the mechanical durability, chemical stability, and responsiveness of mesoporous polymers, broadening their applications in cutting-edge medical technologies. This study provides insight into the application of this hybrid system in medical imaging: MRI, CT scans, and fluorescence imaging. Targeted drug delivery: facilitating the controlled and sustained release of bioactive materials. Regenerative medicine, as bioactive scaffolds for tissue engineering, supports cell adhesion, proliferation, and differentiation. And therapeutic applications such as photothermal and photodynamic therapy. However, despite these advancements, challenges remain, including biocompatibility concerns, potential toxicity, and difficulties in large-scale manufacturing. This study highlights recent innovations, existing challenges, and prospects in metal/metal-oxide nanoparticle-polymer hybrid applications in next-generation healthcare systems. HIGHLIGHTS • The incorporation of metal/metal-oxide nanoparticles into polymers enhances mechanical strength, chemical stability, and responsiveness. • These hybrid materials function as bioactive scaffolds for tissue engineering, supporting cell adhesion, proliferation, and differentiation. • Mesoporous polymer-nanoparticle hybrids enable controlled and sustained drug release. • They play a role in photothermal and photodynamic therapy, allowing minimally invasive cancer treatments.Item Oligochitosan conjugates of the antimalarials dihydroartemisinin and lumefantrine : synthesis, stability, cell viability, and antiplasmodial studies(Wiley, 2025-10) Matshe, William; Mvango, Sindisiwe; Malabi, Rudzani; Tantoh, Asongwe; Andraos, Charlene; Famuyide, Ibukun Michael; McGaw, Lyndy Joy; Baijnath, Sooraj; Pilcher, Lynne A.; Balogun, Mohammed; mohammedbalogun@tuks.co.zaMalaria is treatable with several combinations of drugs, the most well-known and currently most effective being artemisinin-based therapies. Gastrointestinal absorption of these drugs can be poor and erratic if not taken with a fatty meal. Nausea and the loss of appetite, common symptoms of even mild malaria, can therefore jeopardize the effectiveness of the treatment. To enhance the bioavailability of artemisinin-based combination therapies, several lipid-based formulations and delivery systems have been investigated. In this study, we synthesized oligochitosan conjugates of the antimalarial drugs dihydroartemisinin and lumefantrine and examined their physical stability and biological activities. The hydrodynamic properties of both conjugates varied unpredictably under pH conditions like those found at different stages along the gastrointestinal tract and in plasma. The viability of Caco-2 cells exposed to the conjugates was also investigated in comparison to the free drugs. Both conjugates demonstrated significantly lower cytotoxicity compared to the free drugs at concentrations up to 0.5 mg/mL, particularly during the first 24 h of exposure. Despite this, they retained their antiplasmodial effect against Plasmodium falciparum in an in vitro assay at 1 µg/mL and 5 µg/mL. These new chitosan biomaterials hold great potential for further development into oral therapeutics that would not require fatty meal intake due to the intrinsic mucoadhesiveness of chitosan.Item Study of structural, optical, and electrochemical properties of Zn-doped hematite nanoparticles(Elsevier, 2025-11) Rasheed-Adeleke, Azeezat A.; Yusuf, Tunde Lewis; Fayemi, Omolola E.; Seheri, Naledi H.; Oyewo, Opeyemi A.; Ferjani, Hela; Onwudiwe, Damian C.Hematite (α-Fe₂O₃) is a promising material for oxygen evolution reactions but is limited by poor conductivity and rapid charge recombination. This study explores zinc-doped hematite (ZFO) nanoparticles synthesised at 700, 800, and 900 °C to enhance these properties. The Zn doping improved conductivity and optical properties, while the calcination temperature influenced structural and electrochemical characteristics. ZFO nanoparticles were integrated into screen-printed carbon electrodes (SPC-ZFO) and evaluated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV revealed diffusion-controlled electron transfer with strong linearity (R2 ≈ 0.99), and SPC-ZFO electrodes showed higher current responses than bare electrodes, indicating enhanced surface reactivity. EIS results confirmed improved electron mobility, particularly for SPC-ZFO calcined at 900 °C. These findings highlight the role of zinc doping and thermal treatment in optimizing hematite for energy and environmental applications. HIGHLIGHTS • Zn-doped α-Fe₂O₃ (ZFO) was synthesised at varying temps. (700, 800, and 900 °C) • The structural, optical, and electrochemical properties of ZFO were studied. • Zinc doping enhances hematite's conductivity and addresses its inherent limitations. • SPC-ZFO electrodes showed higher current responses than bare electrodes in cyclic voltammetry. • Electrochemical impedance spectroscopy revealed improved electron mobility at 900 °C. • The study demonstrates the potential of ZFO nanomaterials for Advanced materials applications.Item Development of a rapid responsive conductive electrochemical sensor for sensitive hydrogen detection : chitosan-based GO/Fe3O4/PANi hydrogel nanocomposite(Elsevier, 2025-06) Seleka, Wilson M.; Makhado, Edwin; Kganyakgo, Lovedonia K.; Mofokeng, Lethula E.; Makwakwa, Dimakatso; Botlhoko, Orebotse J.Please read abstract in the article.Item Tailoring graphitic carbon nitride for ultracapacitor electrode application through nanocompositing with SnO2 and WO3(Elsevier, 2026-01) Kganyago, Peter; Mamo, Messai Adenew; Mombeshora, Edwin Tonderai; Ndungu, Patrick Gathura; patrick.ndungu@up.ac.zaPlease read abstract in the article.Item Target-specific rhenium(I) tricarbonyl complexes as prospective pharmacological agents : synthesis, X-ray crystallography, and in vitro anticancer evaluation(Elsevier, 2026-01) Ramoba, Lesetja V.; Macharia, Lucy Wanjiku; Chakraborty, Suparna; Prince, Sharon; Malan, F.P. (Frederick); Alexander, Orbett Teboho; Manicum, Amanda Lee EzraPlease read abstract in the article.Item Kinetic analysis of anaerobic coal desulfurization : impact of particle size on sulfur content, ash and calorific value(Elsevier, 2025-09) Makgato, Seshibe; Pappula, Bridjesh; Oyewo, Opeyemi; Yusuf, Tunde Lewis; Kumar, Naveen; Onwudiwe, Damian; Makgwane, PeterKinetic parameters are essential for improving desulfurization efficiency by providing insight into coal properties, reaction rates linked to ash, sulfur content, and calorific value, and for guiding process optimization. The current study develops a kinetic model and evaluates the desulfurization behavior of a bacterial consortium under anaerobic conditions for steam coal. Four particle size fractions (+4.60 mm, -4.60 + 2.30 mm, -2.30 + 1.00 mm, and -0.85 mm) were analyzed. Kinetic parameters were estimated and validated using the AQUASIM software. Over 20 days, total sulfur in the finest coal fraction (-0.85 mm) decreased from 1.45 wt.% to 0.50 wt.% corresponding to a 65.5% desulfurization efficiency under temperature condition of 23 ± 3 °C. Upon increasing the temperature to 30 ± 2 °C, sulfur removal was further improved, with the total sulfur content decreasing to 0.40 wt.%, yielding an overall removal efficiency of 72.4%. Ash in this fraction dropped from 34.2 wt.% to 23.2 wt.%, indicating a 32.2 % reduction. The calorific value improved accordingly, enhancing coal quality. Kinetic analysis showed that reaction rates increased with decreasing particle size, with the -0.85 mm fraction exhibiting the highest reaction rate constant (kmc = 17.474 h⁻¹), while the +4.60 mm fraction recorded the lowest (kmc = 11.105 h⁻¹). Sulfur content and ash removals followed first-order kinetics, confirming that reaction rates were concentration-dependent, while changes in calorific value followed second-order kinetics (R² > 97 %), suggesting more complex dependencies. These findings highlight the critical role of particle size in anaerobic biodesulfurization efficiency and provide a reliable kinetic framework for optimizing microbial coal treatment. HIGHLIGHTS • Particle size significantly influences desulfurization kinetics. • Sulfur and ash reduction followed first-order kinetics, whereas calorific value enhancement followed second-order kinetics. • Reaction Rate Constants Correlate with Particle Size. • Kinetic parameters (kmc and Kc) were modelled using Monod-type equation. • Desulfurization treatment improved coal quality.Item Copper-based electrochemical sensor derived from halogen-substituted Schiff base for selective detection of neurotransmitter dopamine : insight from DFT and docking analysis(Elsevier, 2025-11) Waziri, Ibrahim; Yusuf, Tunde Lewis; Saha, Chandan; Sookai, Sheldon; Adeyinka, Adedapo Sunday; Muller, Alfred J.Please read abstract in the article.Item Design of S-scheme CuInS2/CeO2 heterojunction for enhanced photocatalytic degradation of pharmaceuticals in wastewater(American Chemical Society, 2025-01) Olatunde, Olalekan C.; Waziri, Ibrahim; Onwudiwe, Damian C.; Yusuf, Tunde Lewis; yusuf.tl@up.ac.zaPlease read abstract in the article.Item Identifying skin surface chemicals as potential tuberculosis diagnostic biomarkers using ultra performance liquid chromatography-high resolution mass spectrometry(Elsevier, 2025-05) Wooding, Madelien; Van Pletzen, Kornelis; Naude, Yvette; madelien.wooding@up.ac.zaTuberculosis (TB) remains a significant cause of morbidity and mortality globally, despite its preventability and curability. Early and accurate diagnosis of active TB is essential for enhancing patient care, improving outcomes, and interrupting the transmission cycles of Mycobacterium tuberculosis (M.tb). Metabolomics proves to be an emerging area of study for the development of a non-invasive approach to TB diagnostics.. High-resolution mass spectrometry combined with ion mobility spectrometry enhances the confidence in identifying and annotating biological markers during metabolomic research. This study outlines an analytical workflow encompassing sample preparation through to multivariate analyses for detecting potential TB diagnostic biomarkers. A custom-designed wearable polydimethylsiloxane (PDMS) sampler was employed as a passive sampling device, effectively concentrating chemical compounds from the skin surface. The sampler was directly desorbed into solvent within an LC vial, streamlining the extraction-to-analysis process. Utilising accurate mass and collision cross sections (CCS), fourteen biomarkers were tentatively identified, demonstrating the ability to differentiate TB patients from control groups. Receiver operating characteristic (ROC) analysis yielded an area under the curve (AUC) of 0.911. Among these, para-aminobenzoic acid (PABA) emerged as a promising biomarker for TB, achieving a specificity of 1, sensitivity of 0.9, and an AUC of 0.961. Method limits of detection for the 1-hour non-invasive skin sampling method ranged from 6 (PABA) to 172 ng (phenylalanine) for a calibration working range of 10 – 800 ng with a R2 of ≥ 0.99. These first results demonstrate the potential of using skin surface compounds in TB diagnostics.Item Cutaneous volatile and semi-volatile organic compounds as markers of malaria-infection by wearable samplers and two-dimensional gas chromatography—time-of-flight-mass spectrometry(Elsevier, 2025-11) Pretorius, Daniel Thomas; Rohwer, Egmont Richard; Naude, Yvette; yvette.naude@up.ac.zaMalaria has been found to alter normal cutaneous volatile organic compound (VOC) profiles, suggesting their potential application as markers of Plasmodium infection. The cutaneous VOCs and semi-VOCs (SVOCs) of malaria-negative and -positive individuals, who visited two local clinics in the Vhembe district of Limpopo Province, South Africa, were extracted into wearable silicone rubber (polydimethyl siloxane [PDMS]) sampling bands adhered to the surface of the epidermis. After sampling of epidermal VOCs from participants the samplers were analysed by thermal desorption-comprehensive two-dimensional gas chromatography-time-of-flight-mass spectrometry (TD-GC × GC-TOFMS). Individual cutaneous VOCs and SVOCs profiles were constructed from these complex chromatographic profiles in order to identify potential signatures of Plasmodium infection. Fatty acid compounds associated with rancid malodour, and previously reported as mosquito attractants, were found at an overall greater abundance in chemical profiles of malaria-positive cases. A targeted analysis was performed for compounds previously reported to be associated with Plasmodium infection, viz., heptanal, (E)-2-octenal, 2-octanone, octanal, nonanal and (E)-2-decenal. The linearity (R2) range was 0.93–0.99 for a matrix matched (simulated cutaneous sampling) calibration range of 2.5–60 ng. Limits of detection (LOD) ranged from 0.4 pg (2-octanone) to 6.3 pg ((E)-2-octenal), whilst limits of quantification (LOQ) ranged from 1.4 pg to 21.1 pg. The mean percentage recoveries (n = 2) ranged from 77.8 % ((E)-2-decenal) to 118.9 % (2-octanone). The percentage relative standard deviations ( %RSDs; n = 2) ranged from < 1 % for 2-octanone, octanal and nonanal to 27.1 % for (E)-2-octenal. We found that this particular suite of compounds, previously reported as indicators of malaria, was in fact non-specific for Plasmodium infection when compared to control subjects with comorbidities. A previously unreported (in a malaria-infection context) compound, (E)-2-octen-1-ol, correlated with malaria-positive participants, but was also observed for two malaria-negative participants, which could indicate latent malaria. In chronic cases, Plasmodium vivax can occur in reservoirs outside of the bloodstream, and thus blood-based diagnostic tests can miss latent infection. A key advantage of the epidermal sampler over blood tests is that the former collects whole-body organic compounds, and is therefore not limited to blood-borne markers of infection. As such it appears to be feasible for future investigations.Item Learning organic chemistry on the go : chemical engineering students’ perceptions of Chirality 2 app as a learning support(American Chemical Society, 2025-04) Mosala, Tisetso; Mathabathe, Kgadi Clarrie; Tekane, RethabileAlthough the use of mobile-based learning applications in organic chemistry is rising, limited studies have evaluated their effectiveness as learning supports. This study presents a phenomenographic investigation into the evaluation of using the Chirality 2 app as a learning support in a first-year chemical engineering organic chemistry course in a South African University context. An open-ended questionnaire was used to probe students’ perceptions of the course and their suggestions regarding improving the Chirality 2 app. The findings revealed that students used the app to practice, revise, and test their understanding of organic chemistry concepts in preparation for class tests. Although the students liked the Chirality 2 app for providing immediate feedback, they also expressed dissatisfaction with the lack of detailed feedback for the incorrect answers, and the fact that they were restricted only to multiple-choice questions. The study offers valuable insights into the potential use of gaming apps as equitable learning tools to support organic chemistry students in diverse and resource-limited environments.Item Copper(II) complexes derived from halogen-substituted Schiff base ligands : synthesis, crystal structures, antibacterial activity, and molecular docking studies(American Chemical Society, 2025) Yusuf, Tunde Lewis; Waziri, Ibrahim; Oladipo, Segun D.; Abd El-Maksoud, Mostafa S.; Muller, Alfred J.; Vatsha, Banele; yusuf.tl@up.ac.zaIn the face of escalating bacterial resistance to conventional antibiotics, the quest for novel antimicrobial strategies is urgenter than ever. Metal complexes, particularly those with biological activity, stand out as a promising alternative due to their unique mechanisms of action and potential for fewer side effects in comparison to standard organic antibiotics. This investigation focuses on the synthesis and characterization of six Cu(II) complexes, each formulated from halogen-substituted bidentate Schiff base ligands. Employing a suite of analytical methods, Fourier transform infrared, UV–vis, elemental analysis, and single-crystal X-ray diffraction, the structures of the complexes were fully established. All of the complexes were assigned to have square planar geometry, with the ligand acting as a bidentate and coordinate to the Cu(II) ion via nitrogen and oxygen atoms. The antibacterial efficacy of these complexes was rigorously tested against both Gram-positive bacteria Staphylococcus aureus and Streptococcus pyogenes and Gram-negative bacteria Escherichia coli and Klebsiella pneumoniae, utilizing the broth microdilution technique. The results revealed a spectrum of activity, with minimum inhibitory concentrations (MICs) spanning from less than 15.63 to 125 μg/mL. Notably, Complex 2 demonstrated remarkable potency against S. aureus and S. pyogenes, registering an MIC of less than 15.63 μg/mL. To elucidate the underlying mechanism of action, molecular docking studies were performed targeting the topoisomerase IV receptor. The docking outcomes corroborated the empirical data, underscoring the strong affinity of the complexes for the bacterial targets.Item Chemical analysis of alliin-rich Allium sativum (Garlic) extract and its safety evaluation in Drosophila melanogaster(Elsevier, 2024-12) Oyaluna, Zeniat Emike; Abolaji, Amos Olalekan; Bodede, Olusola; Olanlokun, John Oludele; Prinsloo, Gerhard; Steenkamp, Paul; Babalola, Chinedum PeaceGarlic (Allium sativum) has been traditionally valued for its medicinal properties attributed to the presence of organosulfur compounds. Despite its benefits, concerns about herbal extract toxicity have arisen, necessitating safety assessment. This study was designed to evaluate the chemical analysis and safety profile of Alliin-Rich Garlic Extract (ARGE) using Drosophila melanogaster as a model organism. The ARGE was extracted from garlic cloves (Allium sativum Linn: UIH-23262) using a microwave-assisted method and characterized using UPLC-ESI-MS, 1H NMR, HPLC and IR. Its safety evaluation was determined using D. melanogaster (Harwich strain), and various assays were conducted on 1–3-day-old flies. Toxicological markers and oxidative stress were assessed to understand the impact of ARGE on the flies. Chemical profiling of ARGE using UPLC-ESI-MS, confirmed the presence of alliin (S-ally-L-cysteine-S-oxide), L-arginine, γ-glutamylmethionine, S-(2-carboxypropyl) glutathione, N-γ-glutamyl-S-(1-propenyl) cysteine, N-γ-glutamyl-S-(2-propenyl) cysteine, N-γ-glutamylphenylalanine, S-(allylthio) cysteine, γ-glutamyl-S-allylthiocysteine and eruboside B. HPLC confirmed an alliin content of 0.073 mg/g. Toxicological assessment in D. melanogaster revealed that ARGE enhanced antioxidant defenses by increasing total thiol levels and GST activity, while reducing acetylcholinesterase activity. No significant alteration was observed in catalase activity and cellular metabolic rate. Histological examination revealed no alterations in the histoarchitecture of the brain, fat body or gut of D. melanogaster. The study demonstrated the safety of ARGE in D. melanogaster, supporting its potential as a safe herbal remedy.Item Analytical application of carbon dot-based molecularly imprinted polymers in the fabrication of selective fluorescence and electrochemical sensors – a review(Elsevier, 2026-01) Ng'andu, Clever; Nsibande, Sifiso Albert; sifiso.nsibande@up.ac.zaCarbon quantum dots (CQDs) offer unique chemical and optical properties which have led to their adoption in designing chemical sensors for environmental and biological applications. They have several advantages over heavy metal-based quantum dots, including low toxicity and biocompatibility, which have made them attractive for researchers. They can also be modified and incorporated with molecularly imprinted polymers (MIPs) to fabricate highly selective composite materials for the determination of target analytes. In this work, we first make a case for this specific review in the literature, considering other reviews that have been published on this subject. Then, we briefly introduce the reader to commonly used strategies for the synthesis of CDs and CD-MIPs for selective optical and electrochemical sensor fabrication. Subsequently, we discuss recent research advancements in the synthesis and application of these sensors across various matrices, with an emphasis on the determination of biologically relevant analytes, environmental monitoring, and food safety and quality assessment. Ultimately, key findings are highlighted, and future perspectives for this field are shared. HIGHLIGHTS • Preparation of carbon dots modified with molecularly imprinted polymers (CD-MIPs) for chemosensing. • Analytical performance of the fluorescence and electrochemical sensors with CD-MIP recognition units. • Applications of the CD-MIP sensors in food analysis, environmental monitoring, and sensing of biorelevant compounds. • Challenges and prospects of chemosensors with CD-MIP recognition units.Item Techno-economic evaluation of retrofitting power-to-methanol : grid-connected energy arbitrage vs standalone renewable energy(Elsevier, 2026-02) Mbatha, Siphesihle; Ghaebi Panah, Payam P.; Cui, Xiaoti; Debiagi, Paulo Eduardo Amaral; Louis, Benoît; M.Musyoka, Nicholas; Everson, Raymond C.; Parkhomenko, Ksenia; Langmi, Henrietta WakunaThe power-to-methanol (PtMeOH) will play a crucial role as a form of renewable chemical energy storage. In this paper, PtMeOH techno-economics are assessed using the promising configuration from the previous work (Mbatha et al. [1]). This study evaluated the effect of parameters such as the CO2 emission tax, electricity price, and CAPEX reduction on the product methanol economic parity with respect to a reference case. Superior to previous economic studies, a scenario where an existing methanol synthesis infrastructure is 100 % retrofitted with the promising electrolyser is assessed in terms of its economics and the associated economic parity. The volatile South African electricity market is considered as a case study. The sensitivity of the PtMeOH and green H2 profitability are checked. Grid-connected and standalone renewable energy PtMeOH scenarios are assessed. Foremost, generalisable effect trends of these parameters on the net present value (NPV) and the levelized cost of methanol(LCOMeOH) and H2 (LCOH2) are discussed. The results show that economic parity of H2 (LCOH2 = current selling price = 4.06 €/kg) can be reached with an electricity price of 30 €/MWh and 70 % of the CAPEX. While the LCOMeOH will still be above 2 €/kg at 80 % of the CAPEX and electricity price of 20 €/MWh. This indicates that even if the CAPEX reduces to 20 % of its original in this study, and the electricity price reduces to about 20 €/MWh, the LCOMEOH will still not reach economic parity (LCOMeOH > current selling price = 0.44 €/kg). The results show that to make the retrofitted plant, with a minimum of 20 years of life span, profitable, a feasible reduction in the electricity price to below 10 €/MWh along with favourable incentives such as CO2 credit and reduction in CAPEX, particularly that of the electrolyser, and treatment of the PtMeOH as a multiproduct plant will be required. HIGHLIGHTS • Techno-economics of a 100kton/year retrofitted power-to-methanol are studied. • Grid-connected energy arbitrage and standalone scenarios are investigated. • Generalisable effect trends of key economic bearing parameters are discussed. • To be profitable, a reduction in electricity price to < 10 €/MWh is required. • Power-to-methanol should be treated as a multi-product plant to improve profit.Item Hydrogen production via potassium formate hydrolysis on metal-organic framework supported Pd-based catalysts(Wiley, 2025) Li, Ke; Cai, Tianyi; Li, Jiaye; Dlamini, Mbongiseni William; Sun, Zhiqiang; Sun, ZhaoPlease read abstract in the article.