Research Articles (Chemistry)

Permanent URI for this collection

https://hdl.handle.net/10566/387

Browse

Now showing 1 - 20 of 274

Synthesis, in silico and antimicrobial activity study of substituted aromatic imines and their corresponding amines
(Elsevier B.V., 2025) Abbo, Hanna; Holman, Darin Edward; Hendricks, Mohamed-Deen; Salubi, Christiana Abimbola; Keyster, Marshall; Titinchi, Salam
The antimicrobial properties of Schiff bases and their corresponding amines were assessed by exploring the impact of substituent variations on these activities. The present study involved the synthesis of Schiff base compounds and their corresponding sec-amines, characterization, antibacterial testing, and molecular docking studies. These compounds featured diverse structural components, including alkyl chains, phenyl and methoxy groups. Three of the synthesized compounds are new, viz. N-[(2,3-dimethoxyphenyl) methylene]-1-propanamine (1), N-[(2,3-dimethoxyphenyl)methyl]-1-propanamine (2) and N-[(2,3-dimethoxyphenyl)methylene]-1-butanamine (3). The assessment of antibacterial properties targeted two strains recognized as opportunistic pathogens. Notably, all Schiff base compounds possessing the −C=N moiety exhibited good antibacterial activity against P. aeruginosa and P. agglomerans. Specifically, 1 and 3 demonstrated exceptional effectiveness against the tested bacterial strains, showcasing promising antibacterial capabilities. Furthermore, binding energy calculations revealed that compounds 1 and 3 exhibited binding energies of −3.9, −4.1, and −3.8, −3.9 kcal/mol with respect to P. agglomerans and P. aeruginosa candidate proteins, respectively. This underscores the strong interaction between the synthesized compounds and the bacterial strains, further supporting their potential as potent antimicrobial agents. P. aeruginosa and P. agglomerans were found to be sensitive to both compounds 1 and 3, as well as the standard control ampicillin. The MIC values for P. aeruginosa were 10 mM for 1, and 6 mM for 3. While for P. agglomerans, the MIC values were 6 mM for both 1 and 3.
Persistent pharmaceuticals in a South African urban estuary and bioaccumulation in endobenthic sandprawns (Kraussillichirus kraussi)
(Multidisciplinary Digital Publishing Institute (MDPI), 2025) Petrik, Leslie; Murgatroyd, Olivia; Ojemaye, Cecilia
Pharmaceuticals are increasingly being detected in coastal ecosystems globally, but contamination and bioaccumulation levels are understudied in temporarily closed estuaries. In these systems, limited freshwater inputs and periodic closure may predispose them to pharmaceutical accumulation. We quantified in situ water column pharmaceutical levels at five sites in a temporarily closed model urban estuary (Zandvlei Estuary) in Cape Town, South Africa, that has been heavily anthropogenically modified. The results indicate an almost 100-fold greater concentration of pharmaceuticals in the estuary relative to False Bay, into which the estuary discharges, with acetaminophen (max: 2.531 µg/L) and sulfamethoxazole (max: 0.138 µg/L) being the primary pollutants. Acetaminophen was potentially bioaccumulative, while nevirapine, carbamazepine and sulfamethoxazole were bioaccumulated (BAF > 5000 L/kg) by sandprawns (Kraussillichirus kraussi), which are key coastal endobenthic ecosystem engineers in southern Africa. The assimilative capacity of temporarily closed estuarine environments may be adversely impacted by wastewater discharges that contain diverse pharmaceuticals, based upon the high bioaccumulation detected in key benthic engineers.
Advancement in electrochemical sensing of chloramphenicol in varying matrixes: a review
(Elsevier B.V., 2025) Mulaudji, Kgwadu Percy; Mokwebo, Kefilwe Vanessa; De Bruin, Franklin Quelain; Pokpas, Keagan; Ross, Natasha
Chloramphenicol (CAP) have demonstrated its broad effectiveness against bacterial infections. However, its persistence in the environment and potential toxicity led to strict global regulations limiting its use. As a result, rapid and accurate detection methods for CAP are being developed to protect public health and maintain regulatory compliance regarding its presence in the environment. Conventional analytical methods such as High-Performance Liquid Chromatography, Gas Chromatography, and Liquid Chromatography–Mass Spectrometry were commonly used for CAP detection. However, these conventional methods suffer challenges such as time-consumption, fabrication complexity, reproducibility, and cost. With electrochemical sensing techniques presenting varying valuable benefits, such as instant detection, low power consumption, simultaneous analysis, and portability, making them essential for timely monitoring of various analytes. The performance of electrochemical sensor is further boosted by integrating materials such as spinels, metal oxides, and metallic nanoparticles. These materials are broadly investigated as electrode interface components thanks to their features that collectively boost electrochemical sensor such as providing excellent electrical conductivity, distinct catalytic behavior, and larger surface areas. Furthermore, this paper reviews the impact of traditional and standards analytical methods, as well as their recent advancement based on the detection of CAP in aqueous media.
Biogenic silica derived from sugarcane bagasse as a precursor material for unmodified SBA-15: physicochemical properties and their use in biodiesel production from spent oil
(John Wiley and Sons Ltd, 2025) Matthews, Tatum; Seroka, Ntalane Sello; Khotseng, Lindiwe
Sustainable energy production requires innovative approaches to decrease the dependence on nonrenewable resources and reduce environmental impacts. In this proof-of-concept study, we investigated green Santa Barbara Amorphous 15 (SBA-15) catalysts using sugarcane bagasse ash (SCBA) as a silica source and incorporating organic acids and bases to create an eco-friendly synthesis pathway. These catalysts were applied in the transesterification of waste sunflower oil (WSO) to produce biodiesel. Although the overall biodiesel yields were relatively low, peaking at 5.603% FAME with the L-cysteine-modified SBA-15 catalyst (Lcys-500), the main objective of this study was to establish the feasibility of employing green SBA-15 materials as effective catalysts, rather than to optimise reaction parameters or maximise yield. Catalyst characterisation was carried out using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM–EDS), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA), confirming that the green SBA-15 retained key structural properties of conventional SBA-15, including ordered mesoporosity (p6mm symmetry) and spherical morphology with some variation in pore structure and thermal behaviour. Gas chromatography–mass spectrometry (GC–MS) was employed solely for biodiesel product analysis. FTIR spectra of the biodiesel confirmed successful transesterification, as indicated by characteristic C=O and C–O stretching bands. However, issues such as solidification of the CA-500-derived biodiesel and the low yield from the OP-after calcination sample (0.178%) underscore the need for further refinement. Importantly, catalyst modification strategies, such as surface functionalisation or metal doping, were beyond the scope of this initial study. Overall, the results support the feasibility of producing functional mesoporous SBA-15 catalysts from agricultural waste through green chemistry approaches. This study lays the groundwork for the development of environmentally friendly silica-based catalysts, with future research focussed on surface functionalisation to improve catalytic performance ecologically.
The effect of copolymerization on the electrocatalytic hydrogen evolution properties of polyaniline in acidic medium
(Discover, 2025) Ramohlola, Kabelo E; Ndipingwi, Miranda M.; Iwuoha, Emmanuel I.
In this work, we explore the electrochemical hydrogen evolution reaction (HER) properties of polyaniline homopolymer and copolymers synthesized via the chemical polymerization route. The as-prepared polyaniline (PANI) homopolymer, poly (aniline-co-3-aminobenzoic acid) (P(ANI-co-ABA), poly (aniline-co-triphenylaniline) (P(ANI-co-TPA) and poly (aniline-co-3-nitroaniline) (P(ANI-co-3NI) were characterized and interrogated using several analytical techniques. The FTIR and XRD analyses revealed similar resemblance between PANI homopolymer and copolymers, suggesting that the polymer backbone were not disrupted during copolymerization. Furthermore, the reduction in optical band gap for P(ANI-co-3NI) means that the said copolymer exhibits higher electrical conductivity, which is of great importance for HER applications. In contrast, the HER performance of the as-prepared polymers was evaluated using cyclic voltammetry (CV), linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). The highly conductive P(ANI-co-3NI) exhibited superior HER performance with higher surface coverage, electrochemical surface area and faster kinetics as compared to other as-prepared polymers. Moreover, P(ANI-co-3NI) copolymer possessed a Tafel slope of 47.9 mV.dec−1, 318 mV overpotential at a current density of 1.0 mA.cm−2 and turnover frequency (TOF) of 3 mmol H2.s−1 which are noticeable higher HER performance than that of PANI homopolymer (Tafel slope of 64.6 mV.dec−1 and TOF of 0.25 mmol H2.s−1). The P(ANI-co-3NI) copolymer showed a good long term chronoamperometric stability. This study provides an efficient route for the development of metal-free electrocatalyst with excellent HER performance.
Electrolyte design for lithium-sulfur batteries: progress and challenges
(Elsevier Ltd, 2025) Iwuoha, Emmanuel; Jan, Waleed; Khan, Adnan Daud
Lithium-sulfur batteries (LiSBs) have gained popularity in recent years because of their high specific capacity (1675 mAh/g), high energy density (2600 Wh/kg) and abundance of sulfur in nature. Yet, unlike Lithium-ionbatteries, their commercialization has been challenging. In spite of significant studies on cathodes made of sulfur, lithium metal anodes, changes in separator topologies, embedded layers in cell topologies, and electrolyte architecture, it is still difficult to explain the polysulfide shuttling effect in electrolytes used in LiSBs. This review provides a comprehensive perspective on electrolyte design and critically examines recent research on electrolytes in LiSBs. It additionally provides distinctive techniques for improving the performance and lifespan of these batteries. In short, this review provides a clear and insightful evaluation of the development, prospects, and challenges related to LiSB electrolytes. The advancement of LiSBs holds immense potential to significantly enhance the sustainability and efficiency of our energy landscape. Hence, this field presents an impactful opportunity for researchers and investors to contribute to a more sustainable future.
Exploring V2O5 nanostructures for enhanced supercapacitor performance with Na2SO4 hydrogel electrolyte
(Elsevier Ltd, 2025) Mishra, Ajay Kumar; Bulla, Mamta; Kumar, Vinay
The present study investigates vanadium pentoxide (V2O5) nanostructures combined with Na2SO4-based gel electrolytes to improve the efficiency and energy storage capability of next-generation supercapacitors. V2O5 with nanorod (NR-I) and nanoflower (NF-II) morphologies were synthesised via hydrothermal methods and characterized using XRD, XPS, SEM, UV–vis, FTIR, AFM, RAMAN and BET techniques. To address leakage and mechanical challenges, self-supporting hydrogel films were fabricated from PVA polymer in a neutral Na2SO4 electrolyte at room temperature without chemical crosslinking agents. The electrochemical study revealed superior specific capacitance for NR-I compared to NF-II in single-electrode configurations with aqueous Na2SO4 electrolyte. Therefore, symmetric supercapacitor devices (NR-I // NR-I) were assembled using PVA-Na2SO4 hydrogel and aqueous Na2SO4 electrolytes. The hydrogel-based device demonstrated superior performance, achieving a specific energy of 29 Wh kg−1 and a specific power of 0.79 kW kg−1 at 1 A g−1 within a 1.6 V operating window. Additionally, it retained over 95.2 % of its original capacitance at 8 A g−1 after 2000 cycles and exhibited excellent cyclability, maintaining stable performance up to 5000 cycles. The present research offers a novel approach to enhancing supercapacitor performance by integrating V2O5 nanostructures with PVA-Na2SO4 hydrogel electrolytes, utilizing self-supporting films to address leakage and improve device efficiency. [Display omitted] •1-D and 3-D morphologies using Hydrothermal approach.•A self-supporting hydrogel-based symmetric device was fabricated.•Symmetric device (V2O5//V2O5) delivers a high energy density of 29 Wh kg−1.•The device retains 95.2 % capacitive retention after 2000 cycles.
Function‐oriented electrolyte additives: chemical strategy to enhance the performance of lithium‐sulfur batteries
(John Wiley and Sons Ltd, 2025) Linkov, Vladimir; Liu, Fangfang; Ji, Shan
Lithium‐sulfur (Li‐S) batteries have emerged as a promising candidate for next‐generation energy storage systems. However, the practical application of Li‐S batteries faces several significant technical challenges, such as the “shuttle effect,” sluggish polysulfide conversion kinetics, irreversible loss of active materials, and disordered growth of lithium dendrites on the anode. To overcome these issues, the strategic incorporation of functional electrolyte additives has emerged as a novel approach for enhancing Li‐S battery performance. This paper focuses on reviewing functional electrolyte additives with different properties and their action mechanisms. First, based on the structure and composition of additive molecules, they are classified into inorganic molecules, organic molecules, ionic liquids, and polymer‐based additives. Then, the effects of additives on sulfur cathodes are deeply expounded from aspects such as sulfur fixation, construction of interfacial CEI layers, alteration of sulfur redox pathways, and realization of 3D deposition of Li₂S. Furthermore, the construction of SEI layers on lithium metal anodes, lithium ion migration, and inhibition of lithium dendrites by additives are summarized and compared. Finally, the future development of electrolyte additives for Li‐S batteries is projected, offering theoretical insights and technological strategies for the development of a highly stable Li‐S battery.
Green synthesis, XRD/SAXS modelling and electrochemistry of indium iron oxide nanocomposite
(Springer Science and Business Media B.V., 2025) Ngema, Nokwanda Precious; Tshobeni, Ziyanda; January, Jaymi; Iwuoha, Emmanuel; Ngece-Ajayi, Rachel Fanelwa; Mulaudzi, Takalani
A green synthesis approach was utilized to prepare indium iron oxide (InFeO 3 ) nanocomposites using coffee extract as a reducing and capping agent. The structural, morphological, optical, and electrochemical properties of the synthesized materials were systematically characterized through X-ray diffraction (XRD), small-angle X-ray scattering (SAXS), high-resolution electron microscopy (HRTEM/HRSEM), Fourier-transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, photoluminescence (PL), vibrating sample magnetometry (VSM), and Mössbauer spectroscopy. XRD analysis confirmed the formation of a rhombohedral InFeO 3 structure with an average crystallite size of 27 nm, while HRTEM revealed spherical nanoparticles with partial agglomeration. SAXS and HRTEM data corroborated the nanoscale dimensions, with particle sizes ranging from 24 to 38 nm. Optical studies demonstrated a reduced bandgap (2.85 eV) for the composite compared to pure In 2 O 3 (3.3 eV) and Fe 2 O 3 (3.15 eV), attributed to charge transfer transitions between Fe 3+ and In 3+ . The nanocomposite exhibited enhanced magnetic properties, with a saturation magnetization (Ms) of 18.48 emu/g, and Mössbauer spectroscopy revealed disrupted super-exchange interactions due to In 3+ incorporation. Electrochemical analysis showed superior performance of the InFeO 3 -modified electrode, characterized by a higher diffusion coefficient (9.72 × 10 –5 cm 2 s −1 ) and surface concentration (4.62 × 10 –7 mol cm −2 ) compared to individual oxides, indicating improved charge transfer kinetics. These results highlight the potential of green-synthesized InFeO 3 as a promising material for electrochemical sensing applications, combining sustainability with enhanced functional properties.
The structural, electrical and dielectric studies of CMC based biopolymer gel electrolytes for ecofriendly device applications
(John Wiley and Sons Inc, 2025) Mishra, Ajay Kumar; Singh C.P; Shukla P.K
The solution casting procedure has been effectively used to synthesize biopolymer gel electrolytes (BGEs) using carboxymethyl cellulose (CMC) and ammonium thiocyanate (NH4SCN). The XRD patterns of the bio-based green emulsions (BGEs) have provided evidence of the non-crystalline structure of the films. Optical micrographs of BGEs have revealed the formation of homogeneous gel electrolyte films. Complex impedance spectroscopy has been used to investigate the ion transport mechanism and dielectric relaxation dynamics of biopolymer gel electrolyte films over a wide range of temperatures. The conductivity of the gel electrolyte samples has been shown to rise with the amount of salt present. The optimum ionic conductivity, determined at room temperature, is σ = 3.97 × 10−3 Scm−1, and it is achieved in the gel electrolyte sample containing 35 wt% NH4SCN. The variation in ionic conductivity with temperature has shown a blend of Arrhenius and Vogel-Tamman-Fulcher (VTF) characteristics. An analysis has been conducted on the impedance data to investigate the ion transport process using the formalisms of ac conductivity, permittivity, and electric modulus. The dielectric impedance of the BGEs films has been used to determine the charge carrier density and mobility. The electrolyte with the best conductivity has shown a broad range of electrochemical stability, spanning from −1.49 to +1.27 V. The I-t investigations has shown a high transference number (tion ~ 0.99), indicating that ions are the primary contributors to conductivity. The cyclic voltammetry tests have shown excellent reusability, indicating its potential use in devices, such as supercapacitors and rechargeable batteries.
Removal of rhodamine 6G from aqueous solution in a continuous mode using nano-micro composite membranes
(Elsevier, 2025) Petrik, Leslie; Bode-Aluko, Chris Ademola; Pereao, Omoniyi; Omoniyi, Emmanuel
This research presents the production of nanofibers, track-etched membrane, and nanofiber/track-etched composite membranes and their dye rejection studies. Polyamide 6 nanofibers (PA6-nfs) and polyacrylonitrile nanofibers (PAN-nfs) were fabricated using an electrospinning technique. Their respective composites with the metalized track-etched polyethylene terephthalate film (PET-TM), PET-TMPA6, and PET-TMPAN were also fabricated via electrospinning. The membranes were characterized using HRSEM, TEM, BET, and TGA techniques. The rejection experiments were studied with respect to the pH and the concentration of rhodamine 6G (RD), as well as the flow rate of the system. The pH is the most significant parameter in the filtration system at higher dye concentrations. At pH 10, the rejection percentages of 10 mg/L RD were 91.27% for PET-TMPAN and 70.66% for PET-TMPA6 at a flow rate of 1 mL/min. Also, PAN-nfs, PA6-nfs, and PET-TM gave 65.97%, 36.80%, and 24.53%, respectively. The composite membranes have higher rejection capabilities in comparison to their respective nanofibers. The performance of PET-TMPAN at a lower flow rate of 0.5 mL/min showed that the RD rejection by PET-TMPAN increased by ≈5 percent (91.27 to 96.01). At a lower concentration of 2 mg/L (to simulate higher dilution in river water) and pH (5.6), PET-TMPAN had a 99.59% RD rejection. All the membranes were regenerated and reused. The composite membrane PET-TMPAN has the capability to remove RD at both higher (96.01%) and lower concentrations (99.59%) of RD at lower flow rate, thereby making the system applicable and easy to use in river water purification.
Effect of 2,2-Dialkyl/Diaryl substituents on the opto-electronics of poly (propylene-3,4-ethylenedioxythiophenoimine)-co-poly(3,4- propylenedioxythiophene) dendritic star copolymers
(Elsevier B.V., 2025) Mdluli, Siyabonga; Ramoroka, Morongwa; John-Denk, Vivian; Iwuoha, Emmanuel
A series of four dendritic star copolymers that consist of G2poly(propyleneamine) dendrimer core, and pendants of poly(propylene-3,4-ethylenedioxythiophene) substituted with 2,2- dibenzyl, 2,2-dicyclohexylmethyl, 2,2-dimethyl, and 2,2-dihexyl that grew out from the core, were synthesized using a combination of Schiff base condensation and chemical oxidative copolymerization techniques. Chemical structures of dendritic star copolymers were examined and confirmed using nuclear magnetic resonance (NMR), Raman, and Fourier transform infrared spectroscopies (FTIR). The effect of the 2,2-dialkyl substituents on the opto- electronics and thermal stability of the dendritic star copolymers was evaluated using ultraviolet-visible spectroscopy (UV–Vis), thermogravimetric analysis (TGA), and photoluminescence (PL). Insertion of long chains of 2,2-dicyclohexyl showed a bathochromic shift and reduction in optical band gap compared to other substituents. TGA revealed less thermal resistance and fast degradation rates at temperatures above 300 °C associated with copolymers decomposition. This work revealed that modification of copolymers with alkyl or aryl substituents alter significantly with their thermal and optical properties by changing the decomposition temperature and optical bandgap.
Trimetallic chalcogenide-sensitised interferon gamma aptasensor for tuberculosis
(Elsevier Ltd, 2025) Uhuo, Onyinyechi Vivian; Januarie, Kaylin Cleo; Mokwebo, Kefilwe Vanessa
Novel copper indium tin sulfide nanomaterial synthesized with chitosan capping agent.•IFN-γ TB biomarker aptasensor was fabricated using a χt-c-CITS sensing platform.•By aptamer surface density study, χt-c-CITS enhanced aptamer loading by 84.6 %.•χt-c-CITS increased aptasensor signal by 73.9 % and target detection by 85.7 %.•"Turn-on" assay format was achieved and monitored by capacitive charge measurements. Tuberculosis (TB) is a highly contagious disease whose eradication has become challenging due to the difficulty of early and real-time diagnosis, especially in developing countries. These challenges arise due to the time-consuming, expensive, complicated, and non-user-friendly nature of the current diagnostic techniques, making them difficult to use except by a highly trained medical laboratory specialist. Since biosensors offer a faster, simpler, and highly sensitive alternative to traditional methods, there is a growing interest in enhancing biosensor signals for efficient application. One such method of biosensor signal amplification is the use of nanostructured materials. In this work, we report the positive effect of tuning the properties of a substituted-kesterite nanomaterial, copper indium tin sulfide (CITS), using a chitosan capping agent, for efficient signal amplification of interferon gamma (IFN-γ) TB biomarker detection. This nanostructured chitosan-capped copper indium tin sulfide (χt-c-CITS) nanomaterials served as an excellent sensing platform, improving aptamer loading by 84.6 % and signal response by 73.9 %. High sensitivity to changes in IFN-γ concentration was obtained with the χt-c-CITS-based aptasensor between 100 fM to 1 pM dynamic linear range, and a detection limit of 23.2 fM. Excellent electrochemical stability was achieved with 94 % and 95.6 % signal stability recorded after 20 repeated chronocoulometry measurements and a 32-day storage period, respectively. The aptasensor likewise showed excellent specificity and selectivity to IFN-γ in the presence of interfering agents, with potential application in real biological samples.
Strong polymer-cellulose interfacial engineering enables hydrogel-enhanced separators with multiscale networks for zinc-ion batteries
(Elsevier B.V., 2025) Iwuoha, Emmanuel; Lang, Aoxue; Guo, Ziyu
Cellulose paper-based separators have attracted significant attention as promising materials for aqueous zinc ion batteries (ZIBs) owing to their excellent wettability, chemical stability, and environmental compatibility. However, water molecules penetrate into the amorphous regions of cellulose to induce plasticization, thus increasing the mobility of molecular chains and disrupting the intermolecular hydrogen bonding within cellulose. This degradation mechanism severely deteriorates battery cycling performance and capacity retention, thereby hindering the utility of cellulose paper-based separators in aqueous ZIBs. Herein, we propose an in situ photo-initiated radical polymerization strategy to integrate acrylamide-nanocellulose hydrogels onto cellulose separators, resulting in the construction of hydrogel-coated composite separators. In this design, the strong polymer-cellulose interfacial interactions restrict cellulose chain mobility, homogenize Zn2+ ion flux, and significantly enhance wet-state mechanical robustness. Consequently, the composite separator ensures structural integrity during prolonged cycling. The assembled Zn|PNF-6|V2O5 full cell demonstrates superior cycle stability, retaining a capacity retention of 80 % over 4000 cycles at 5 A g−1. This work pioneers a scalable route toward high-performance hydrogel-enhanced paper separators, addressing critical challenges for ZIBs industrialization.
Advancements in catalyst design for biomass-derived bio-oil upgrading to sustainable biojet fuel: a comprehensive review
(John Wiley and Sons Inc, 2025) Jideani, Thandiswa; Seroka, Ntalane Sello; Khotseng, Lindiwe
Biomass‐derived bio‐oil, produced through thermochemical methods such as pyrolysis and hydrothermal liquefaction, has immense potential as a renewable feedstock for aviation fuels because of its renewable nature and the potential to significantly reduce greenhouse gas emissions. The development of biojet fuel from renewable sources, such as biomass, is a critical step toward achieving global energy sustainability and reducing the carbon footprint of the aviation industry. This review aims to provide a comprehensive analysis of the advances in catalyst design to upgrade biomass‐derived oil to biojet fuel. The review will also explore the mechanisms by which these catalysts operate, the optimization of catalytic processes, and the performance metrics used to evaluate their efficiency. Recent case studies demonstrate the effectiveness of catalyst design in enabling efficient and sustainable conversion of biomass‐based bio‐oil into high‐quality fuels, advancing the viability of renewable energy sources in aviation and beyond.
Asymmetrical curcumin derivative: synthesis, structural exploration, hirshfeld surface analysis, and computational study
(Springer, 2025) Titinchi, Salam; Abbo, Hanna; Ashfaq, Muhammad
Curcumin derivatives are bioactive compounds with a linear structure and an α,β-unsaturated β-diketone moiety. the chemical reaction of 3-hydroxy-4-methoxybenzaldehyde and cinnamaldehyde in dmf in the presence of acetylacetone and boric oxide mixture resulted in the synthesis of a curcumin derivative named as (1e,4z,6e,8e)-5-hydroxy-1-(4-hydroxy-3- methoxyphenyl)-9-phenylnona-1,4,6,8-tetraen-3-one (hpto). the compound was characterized by ft-ir, ms, 1h-, and 13c-nmr. moreover, crystal structure was determined by single crystal xrd analysis, which displayed the presence of a solvent molecule along with the main molecule (hpto). the geometry of the main molecule was stabilized by intramolecular o–h···o bonding. the molecule adopted a non-planar conformation with a dihedral angle between phenyl rings of 35.1 (1)°. the supramolecular assembly was stabilized by numerous intermolecular interactions that were explored by hirshfeld surface analysis. interaction energy calculations were carried out at b3lyp/6-31 g(d,p) electron density level to support the experimental fndings. void analysis was performed in order to predict the response of the crystal to the applied stress. the compound was studied using the dft method, employing the 6-311 g(d,p) basis set, to evaluate its electronic and quantum chemical properties. frontier molecular orbitals and density of states analyses revealed an energy gap of 3.08 ev. this fnding indicates the compound’s signifcant chemical reactivity and potential for notable biological activity. molecular docking studies were performed to evaluate the compound’s potential as a cancer treatment medication candidate. by employing a multidisciplinary methodology, this research provides a thorough understanding of the compound’s structural features, chemical properties, and prospective pharmaceutical applications, paving the way for its development in cancer treatment.
Simultaneous trifunctional group passivation using imidazole derivatives for enhanced performance of perovskite solar cells
(Elsevier Ltd, 2025) Iwuoha, Emmanuel; Yang, Jun; Niu, Qiaoli
Perovskite solar cells (PSCs) are one of the most promising energy technologies in the field of renewable energy. The solution-based perovskite film-forming method is one of its important advantages in commercialization. However, the polycrystalline perovskite thin films prepared by this method may also exhibit various defects, leading to a decrease in device performance. In this work, an imidazole derivative 1-(2-hydroxyethyl)-3-methylimidazolium chloride (HMCl) was used as a passivator for perovskite thin films. The imidazole moiety and hydroxyl in HMCl passivated the negatively charged I - and positively Pb2+ defects in CH3NH3PbI3 (MAPbI3), respectively. Meanwhile the chloride ion establishes ionic bonds with uncoordinated Pb2+, further enhancing the passivation of defects. With HMCl, the PCE of the PSC was enhanced from 17.53 % of the control device to 19.71 %. In addition, the introduction of HMCl enhanced the hydrophobicity of perovskite films, and therefore, improved the storage stability of PSCs. This study provides an alternative passivator for the development of highperformance and long-term stable PSCs.
Sustainable gliadin - metal oxide composites for efficient inactivation of Escherichia coli and remediation of cobalt (II) from water
(Elsevier ScienceDirect Journals, 2024) Emile Salomon Massima Mouele; Leslie Petrik
Bio-based materials facilitate greener approach to engineering novel materials with multifunctional properties for various applications including water treatment. In this study, we extracted gliadin from wheat gluten using alcoholic solvent. The aggregation limitations of gliadin protein were overcome by functionalisation with metal oxides (MOs) TiO2, AgFe2O3 and AgFe–TiO2 prepared by chemical precipitations. The novel composites were characterised by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fouriertransform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), thermogravimetry analysis (TGA), Brunauer Emmet–Teller (BET), and zeta potential. The multifunctionality of MOs-gliadin composites was tested through toxic Escherichia coli (E. coli) inactivation and Co2+ adsorption from water. The antibacterial results showed excellent inhibition under both dark and light conditions. The maximum Co2+ uptake, 101 mg/g was reached with TiO2@gliadin after 24 h and best fitted the Langmuir isotherm model. The adsorption process followed pseudo-second order model with an equilibrium adsorption capacity, qe2 = 89.86 mg/g closer to the experimental data. Thermodynamic investigations indicated that ΔG◦ = − 9.677 kJ/mol, ΔH◦ = − 123 kJ/mol, and ΔS◦ = 0.490 J.K/mol, respectively, suggesting that adsorption was spontaneous and endothermic. The regenerated TiO2@gliadin composite was still efficient after five consecutive cycles. This study demonstrates that MOs-gliadin blended composites are sustainable for water purification
Stability, deactivation and regeneration study of a newly developed HZSM-5 and Ni-doped HZSM-5 zeolite catalysts for ethanol-to-hydrocarbon conversion
(Elsevier B.V., 2024) Anekwe, Ifeanyi Michael Smarte; Khotseng, Lindiwe
This work investigates the stability and regeneration of HZSM-5 and Ni/HZSM-5 catalysts in the ethanol-to-hydrocarbon conversion. The catalysts were characterised using different techniques and evaluated at 623 K and 7 h−1 for 96 h TOS with two regeneration cycles. HZSM-5 showed high stability with 100% ethanol conversion, while Ni/HZSM-5 catalysts maintained 100% stability for 48 h before dropping. Regenerated catalysts were comparable to the originals in terms of product distribution, stability, and performance. HZSM-5 preferred BTX, while Ni-doped catalysts favoured C5-C8, C9-C12, and C12+ synthesis. The regeneration process restored catalytic activity, especially for the Ni-doped catalysts, extending their life and reducing replacement costs.
Electrical environment can be altered at 1 km distances from high voltage power lines.
(Institute of Physics, 2024) Matthews, James C.; Shallcross, Dudley E
High voltage powerlines emit electrical charges into the atmosphere which can then attach to aerosols. This space charge above ground can be measured directly using ion spectrometers or indirectly through perturbations of the Earth's potential gradient using field mills. Several publications are reviewed to find evidence of aerosol charging at a distance from power lines. Field measurements of charge state near to high voltage power lines selected due to their high emissions of ions measured a small positive enhancement of electrical charge on aerosols at distances greater than 300 m, corresponding to a transit time of up to 400 s A quasi one-dimensional model of ion-aerosol interactions from a high voltage powerlines found that the addition of new ions to an aerosol population will result in those ions transferring charge to the aerosol which would then remain the dominant carrier of charge several hundred meters downwind. 10-min PG measurements from a fixed site measuring in 2008 compared measurements when the site was downwind of a 275 kV powerline to times with no wind and found evidence of space charge overhead through greater fields and variability at distances over 800 m These studies combined show evidence that the electrical environment near to power lines can be altered beyond 1 km from AC high voltage power lines, with excess charges likely to be concentrated on aerosol.

Browse

Recent Submissions