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Prof. Patrick Ndungu
University of Johannesburg, Department of Chemical Sciences

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0 Photo Catalysis
0 dye sensitized solar cells
0 Environmental monitoring
0 Water treatment and reuse
0 carbon nano materials

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Water treatment and reuse
Organic solar cells (OSCs)
Photo Catalysis
dye sensitized solar cells

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Review
Published: 15 July 2021 in Molecules
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Environmental pollutants, such as mycotoxins, pesticides, and pharmaceuticals, are a group of contaminates that occur naturally, while others are produced from anthropogenic sources. With increased research on the adverse ecological and human health effects of these pollutants, there is an increasing need to regularly monitor their levels in food and the environment in order to ensure food safety and public health. The application of magnetic nanomaterials in the analyses of these pollutants could be promising and offers numerous advantages relative to conventional techniques. Due to their ability for the selective adsorption, and ease of separation as a result of magnetic susceptibility, surface modification, stability, cost-effectiveness, availability, and biodegradability, these unique magnetic nanomaterials exhibit great achievement in the improvement of the extraction of different analytes in food. On the other hand, conventional methods involve longer extraction procedures and utilize large quantities of environmentally unfriendly organic solvents. This review centers its attention on current applications of magnetic nanomaterials and their modifications in the extraction of pollutants in food commodities.

ACS Style

Sarem Targuma; Patrick Njobeh; Patrick Ndungu. Current Applications of Magnetic Nanomaterials for Extraction of Mycotoxins, Pesticides, and Pharmaceuticals in Food Commodities. Molecules 2021, 26, 4284 .

AMA Style

Sarem Targuma, Patrick Njobeh, Patrick Ndungu. Current Applications of Magnetic Nanomaterials for Extraction of Mycotoxins, Pesticides, and Pharmaceuticals in Food Commodities. Molecules. 2021; 26 (14):4284.

Chicago/Turabian Style

Sarem Targuma; Patrick Njobeh; Patrick Ndungu. 2021. "Current Applications of Magnetic Nanomaterials for Extraction of Mycotoxins, Pesticides, and Pharmaceuticals in Food Commodities." Molecules 26, no. 14: 4284.

Paper
Published: 22 March 2021 in RSC Advances
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In this work, we report on a reverse micellization approach to prepare uncarbonized starch and poly(1,4-butylene succinate) hybrids with exceptional charge storage performance.

ACS Style

O. D. Saliu; M. A. Mamo; P. G. Ndungu; J. Ramontja. Micellization of a starch–poly(1,4-butylene succinate) nano-hybrid for enhanced energy storage. RSC Advances 2021, 11, 11745 -11759.

AMA Style

O. D. Saliu, M. A. Mamo, P. G. Ndungu, J. Ramontja. Micellization of a starch–poly(1,4-butylene succinate) nano-hybrid for enhanced energy storage. RSC Advances. 2021; 11 (19):11745-11759.

Chicago/Turabian Style

O. D. Saliu; M. A. Mamo; P. G. Ndungu; J. Ramontja. 2021. "Micellization of a starch–poly(1,4-butylene succinate) nano-hybrid for enhanced energy storage." RSC Advances 11, no. 19: 11745-11759.

Journal article
Published: 13 March 2021 in Water Resources and Industry
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Presence of fluoride and pathogen in drinking water is an issue of concern due to their health effects and as such much effort is being directed towards finding sustainable material for use in water treatment. Adsorption based water treatment techniques are often considered as the most effective and easy to use in rural set up. However, most of the adsorbents are not multifunction and are only effective towards fluoride. In this study aluminosilicate activated clay was hydrothermally treated and applied for fluoride and pathogen removal from water. Fourier transform infrared (FTIR), Brunauer-Emmett-Teller method (BET), X-ray diffraction spectroscopy (XRD) and Scanning electron microscopy-energy dispersion spectroscopy (SEM-EDS) techniques were employed to characterize hydrothermally treated aluminosilicate clay (HTAC). Batch defluoridation experiments were used to evaluate the fluoride removal efficiency while well diffusion assay method was used to evaluate the antimicrobial efficiency. The BET results showed increase in surface area from 17.19 m2/g to 33.56 m2/g after treatment. Batch defluoridation showed maximum adsorption capacity of 1.75 mg/g with 53% fluoride removal from initial fluoride concentration of 6 mg/L using 0.8 g/40 mL dosage at initial pH 5.8 and contact time of 5 min at room temperature. The adsorption kinetics data showed a better fit to pseudo-second order model while the adsorption isotherm data showed correlation coefficient and chi-square values of 0.98 and 0.01, respectively indicating a better fit to both Langmuir and Freundlich adsorption isotherms. The regeneration studies showed that the material can be reused for up to six times using 0.1 M KCl as regenerant. Antimicrobial studies showed that HTAC has potency against Escherichia coli (E. coli) strains. The study showed that synthesized HTAC has strong potential for application in fluoride and pathogen removal.

ACS Style

OlumuyiwaA. Obijole; Gitari Wilson Mugera; Rabelani Mudzielwana; PatrickG. Ndungu; Amidou Samie; AyindeW. Babatunde. Hydrothermally treated aluminosilicate clay (HTAC) for remediation of fluoride and pathogens from water: Adsorbent characterization and adsorption modelling. Water Resources and Industry 2021, 25, 100144 .

AMA Style

OlumuyiwaA. Obijole, Gitari Wilson Mugera, Rabelani Mudzielwana, PatrickG. Ndungu, Amidou Samie, AyindeW. Babatunde. Hydrothermally treated aluminosilicate clay (HTAC) for remediation of fluoride and pathogens from water: Adsorbent characterization and adsorption modelling. Water Resources and Industry. 2021; 25 ():100144.

Chicago/Turabian Style

OlumuyiwaA. Obijole; Gitari Wilson Mugera; Rabelani Mudzielwana; PatrickG. Ndungu; Amidou Samie; AyindeW. Babatunde. 2021. "Hydrothermally treated aluminosilicate clay (HTAC) for remediation of fluoride and pathogens from water: Adsorbent characterization and adsorption modelling." Water Resources and Industry 25, no. : 100144.

Journal article
Published: 09 March 2021 in Sustainability
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The ongoing research toward meeting global energy demands requires novel materials from abundant renewable resources. This work involves an investigation on nitrogen-doped carbon nanotubes (N-CNTs) synthesized from relatively low-cost and readily available biomass as carbon precursors and their use as electrodes for supercapacitors. The influence of the ionic liquid 1-butyl-3-methylimidazolium chloride, or its combination with either sugarcane bagasse or cellulose (IL-CNTs, ILBag-CNTs, and ILCel-CNTs, respectively), in the synthesis of N-CNTs and the resultant effect on their physical and electrochemical properties was studied. Systematic characterizations of the N-CNTs employing transmission electron microscopy (TEM), thermogravimetric analysis, X-ray photoelectron spectroscopy (XPS), elemental analysis, nitrogen sorption analysis, cyclic voltammetry, and electrochemical impedance spectroscopy were performed. TEM data analysis showed that the mean outer diameters decreased, in the order of IL-CNTs > ILBag-CNTs > ILCel-CNTs. The N-CNTs possess only pyridinic and pyrrolic nitrogen-doping moieties. The pyridinic nitrogen-doping content is lowest in IL-CNTs and highest in ILCel-CNTs. The N-CNTs are mesoporous with surface areas in the range of 21–52 m2 g−1. The ILCel-CNTs had the highest specific capacitance of 30 F g−1, while IL-CNTs has the least, 10 F g−1. The source of biomass is beneficial for tuning physicochemical properties such as the size and surface areas of N-CNTs, the pyridinic nitrogen-doping content, and ultimately capacitance, leading to materials with excellent properties for electrochemical applications.

ACS Style

Kudzai Mugadza; Annegret Stark; Patrick Ndungu; Vincent Nyamori. Effects of Ionic Liquid and Biomass Sources on Carbon Nanotube Physical and Electrochemical Properties. Sustainability 2021, 13, 2977 .

AMA Style

Kudzai Mugadza, Annegret Stark, Patrick Ndungu, Vincent Nyamori. Effects of Ionic Liquid and Biomass Sources on Carbon Nanotube Physical and Electrochemical Properties. Sustainability. 2021; 13 (5):2977.

Chicago/Turabian Style

Kudzai Mugadza; Annegret Stark; Patrick Ndungu; Vincent Nyamori. 2021. "Effects of Ionic Liquid and Biomass Sources on Carbon Nanotube Physical and Electrochemical Properties." Sustainability 13, no. 5: 2977.

Full paper
Published: 16 September 2020 in Electroanalysis
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Ternary transition metal oxides are promising advanced materials for use as electrode components in electrochemical energy storage systems. However, low electronic/ionic conductivity hinder practical applications. In this study, ternary Mn‐Ni‐Co oxide nanoparticles were encapsulated in carbon nanosheets, to improve the electrical conductivity and surface area. When tested as supercapacitor electrodes, the materials exhibited specific capacity of 91.2 mAh g‐1 at a current density of 1 A g‐1 in 2 M KOH. Moreover, after 3000 cycles the composite achieved a specific capacity of 74.6 mAh g‐1 at a current density of 6 A g‐1 and high capacitance retention of 96.4 %.

ACS Style

Tarekegn Heliso Dolla; Isiaka A. Lawal; Dave G. Billing; Karin Pruessner; Patrick Ndungu. Carbon Encapsulated Ternary Mn−Ni−Co Oxide Nanoparticles as Electrode Materials for Energy Storage Applications. Electroanalysis 2020, 32, 2926 -2935.

AMA Style

Tarekegn Heliso Dolla, Isiaka A. Lawal, Dave G. Billing, Karin Pruessner, Patrick Ndungu. Carbon Encapsulated Ternary Mn−Ni−Co Oxide Nanoparticles as Electrode Materials for Energy Storage Applications. Electroanalysis. 2020; 32 (12):2926-2935.

Chicago/Turabian Style

Tarekegn Heliso Dolla; Isiaka A. Lawal; Dave G. Billing; Karin Pruessner; Patrick Ndungu. 2020. "Carbon Encapsulated Ternary Mn−Ni−Co Oxide Nanoparticles as Electrode Materials for Energy Storage Applications." Electroanalysis 32, no. 12: 2926-2935.

Review
Published: 07 September 2020 in Materials
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Considering its availability, renewable character and abundance in nature, this review assesses the opportunity of the application of biomass as a precursor for the production of carbon-based nanostructured materials (CNMs). CNMs are exceptionally shaped nanomaterials that possess distinctive properties, with far-reaching applicability in a number of areas, including the fabrication of sustainable and efficient energy harnessing, conversion and storage devices. This review describes CNM synthesis, properties and modification, focusing on reports using biomass as starting material. Since biomass comprises 60–90% cellulose, the current review takes into account the properties of cellulose. Noting that highly crystalline cellulose poses a difficulty in dissolution, ionic liquids (ILs) are proposed as the solvent system to dissolve the cellulose-containing biomass in generating precursors for the synthesis of CNMs. Preliminary results with cellulose and sugarcane bagasse indicate that ILs can not only be used to make the biomass available in a liquefied form as required for the floating catalyst CVD technique but also to control the heteroatom content and composition in situ for the heteroatom doping of the materials.

ACS Style

Kudzai Mugadza; Annegret Stark; Patrick G. Ndungu; Vincent O. Nyamori. Synthesis of Carbon Nanomaterials from Biomass Utilizing Ionic Liquids for Potential Application in Solar Energy Conversion and Storage. Materials 2020, 13, 3945 .

AMA Style

Kudzai Mugadza, Annegret Stark, Patrick G. Ndungu, Vincent O. Nyamori. Synthesis of Carbon Nanomaterials from Biomass Utilizing Ionic Liquids for Potential Application in Solar Energy Conversion and Storage. Materials. 2020; 13 (18):3945.

Chicago/Turabian Style

Kudzai Mugadza; Annegret Stark; Patrick G. Ndungu; Vincent O. Nyamori. 2020. "Synthesis of Carbon Nanomaterials from Biomass Utilizing Ionic Liquids for Potential Application in Solar Energy Conversion and Storage." Materials 13, no. 18: 3945.

Journal article
Published: 21 October 2019 in Environmental Research
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Waste from biomass was used to prepare a low–cost biochar–clay hybrid adsorbent. The hybrid adsorbent was synthesised by combining Kaolin with biomass (Vitex doniana), thereafter, modified with Deep Eutectic Solvent (DES). The materials were characterised using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), Thermal gravimetric analysis (TGA), and Brunauer–Emmett–Teller (BET), also, pHpzc of the materials were studied. The resultant adsorbents were used for both column and batch adsorption of organic pollutants; dye (Acid Blue 74; AB74) and pharmaceuticals (ciprofloxacin; CIP and acetaminophen; ACTE). Column adsorption capacity, effect of pollutant concentration and effect of flow rate were studied, also, the column was modelled using Thomas, Yoon-Nelson and Adams-Bohart model. Furthermore, batch adsorption experiments were performed, effect of change in pH, time, dose and concentration were studied. Batch adsorption data were fitted with isotherm and kinetic models. The experiment showed tremendous increase in adsorption capacity when the hybrid adsorbent (HYD) was modified with DES (HYD–DES). Acid Blue 74 on HYD–DES has the highest column sorption capacity followed by ciprofloxacin and acetaminophen. Adsorption was favoured at pH range of 2–10 for both AB74 and ACTE as there is no significant changes in the % removal performance, while adsorption was best at pH 6 and above for CIP. AB74 and CIP are best described by Langmuir isotherm, whereas ACTE adsorption was best explained by Freundlich isotherm equilibrium. The DES modified HYD has shown it can be effectively utilised as possible adsorbent for adsorbing organic dyes and pharmaceuticals.

ACS Style

Isiaka A. Lawal; Michael Klink; Patrick Ndungu. Deep eutectic solvent as an efficient modifier of low-cost adsorbent for the removal of pharmaceuticals and dye. Environmental Research 2019, 179, 108837 .

AMA Style

Isiaka A. Lawal, Michael Klink, Patrick Ndungu. Deep eutectic solvent as an efficient modifier of low-cost adsorbent for the removal of pharmaceuticals and dye. Environmental Research. 2019; 179 ():108837.

Chicago/Turabian Style

Isiaka A. Lawal; Michael Klink; Patrick Ndungu. 2019. "Deep eutectic solvent as an efficient modifier of low-cost adsorbent for the removal of pharmaceuticals and dye." Environmental Research 179, no. : 108837.

Journal article
Published: 21 October 2019 in International Journal of Environmental Research and Public Health
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There is growing interest in determining the unidentified peaks within a sample spectra besides the analytes of interest. Availability of reference standards and hyphenated instruments has been a key and limiting factor in the rapid determination of emerging pollutants in the environment. In this work, polar compounds were silylated and analyzed with gas chromatography mass spectrometry (GC-MS) to determine the abundant fragments within the single ion monitoring (SIM) mode and methodology. Detection limits and recoveries of the compounds were established in river water, wastewater, biosolid and sediment matrices. Then, specific types of polar compounds that are classified as emerging contaminants, pharmaceuticals and personal care products, in the environment were targeted in the Mgeni and Msunduzi Rivers. We also performed suspect and non-target analysis screening to identify several other polar compounds in these rivers. A total of 12 compounds were quantified out of approximately 50 detected emerging contaminants in the Mgeni and Msunduzi Rivers. This study is significant for Africa, where the studies of emerging contaminants are limited and not usually prioritized.

ACS Style

Bhekumuzi Prince Gumbi; Brenda Moodley; Grace Birungi; Patrick Gathura Ndungu. Target, Suspect and Non-Target Screening of Silylated Derivatives of Polar Compounds Based on Single Ion Monitoring GC-MS. International Journal of Environmental Research and Public Health 2019, 16, 4022 .

AMA Style

Bhekumuzi Prince Gumbi, Brenda Moodley, Grace Birungi, Patrick Gathura Ndungu. Target, Suspect and Non-Target Screening of Silylated Derivatives of Polar Compounds Based on Single Ion Monitoring GC-MS. International Journal of Environmental Research and Public Health. 2019; 16 (20):4022.

Chicago/Turabian Style

Bhekumuzi Prince Gumbi; Brenda Moodley; Grace Birungi; Patrick Gathura Ndungu. 2019. "Target, Suspect and Non-Target Screening of Silylated Derivatives of Polar Compounds Based on Single Ion Monitoring GC-MS." International Journal of Environmental Research and Public Health 16, no. 20: 4022.

Original article
Published: 11 September 2019 in Environmental Processes
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The removal efficiency of As(III) by kaolin clay modified by Fe-Mn bimetal oxides was successfully evaluated. Modification of kaolin clay by Fe-Mn oxides increased the surface area of the kaolin clay from 19.2 to 29.8 m2/g and further decreased the pore diameter from 9.54 to 8.5 nm. As(III) removal efficiency was optimum at pH < 8 and was inhibited at pH >8. The adsorption isotherm data fitted well to Langmuir adsorption isotherm model with a maximum adsorption capacity of 2.93 mg/g at initial As(III) concentration range of 1 to 30 mg/L. The adsorption kinetics data was described better by pseudo-second order of reaction kinetics indicating that As(III) sorption occurred via chemisorption. Thermodynamics studies revealed that As(III) adsorption occurs spontaneously and the reaction is exothermic in nature. Compared to other reported adsorbents, Fe-Mn bimetal kaolin showed higher adsorption capacity making it a suitable candidate for As(III) removal from groundwater.

ACS Style

R. Mudzielwana; W. M. Gitari; Patrick Ndungu. Removal of As(III) from Synthetic Groundwater Using Fe-Mn Bimetal Modified Kaolin Clay: Adsorption Kinetics, Isotherm and Thermodynamics Studies. Environmental Processes 2019, 6, 1005 -1018.

AMA Style

R. Mudzielwana, W. M. Gitari, Patrick Ndungu. Removal of As(III) from Synthetic Groundwater Using Fe-Mn Bimetal Modified Kaolin Clay: Adsorption Kinetics, Isotherm and Thermodynamics Studies. Environmental Processes. 2019; 6 (4):1005-1018.

Chicago/Turabian Style

R. Mudzielwana; W. M. Gitari; Patrick Ndungu. 2019. "Removal of As(III) from Synthetic Groundwater Using Fe-Mn Bimetal Modified Kaolin Clay: Adsorption Kinetics, Isotherm and Thermodynamics Studies." Environmental Processes 6, no. 4: 1005-1018.

Journal article
Published: 15 August 2019 in International Journal of Environmental Analytical Chemistry
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ACS Style

Lydiane G. Djemmoe; Evangeline Njanja; Francis M. M. Tchieno; Derek T. Ndinteh; Patrick G. Ndungu; Ignas K. Tonle. Activated Hordeum vulgare L. dust as carbon paste electrode modifier for the sensitive electrochemical detection of Cd2+, Pb2+ and Hg2+ions. International Journal of Environmental Analytical Chemistry 2019, 100, 1429 -1445.

AMA Style

Lydiane G. Djemmoe, Evangeline Njanja, Francis M. M. Tchieno, Derek T. Ndinteh, Patrick G. Ndungu, Ignas K. Tonle. Activated Hordeum vulgare L. dust as carbon paste electrode modifier for the sensitive electrochemical detection of Cd2+, Pb2+ and Hg2+ions. International Journal of Environmental Analytical Chemistry. 2019; 100 (13):1429-1445.

Chicago/Turabian Style

Lydiane G. Djemmoe; Evangeline Njanja; Francis M. M. Tchieno; Derek T. Ndinteh; Patrick G. Ndungu; Ignas K. Tonle. 2019. "Activated Hordeum vulgare L. dust as carbon paste electrode modifier for the sensitive electrochemical detection of Cd2+, Pb2+ and Hg2+ions." International Journal of Environmental Analytical Chemistry 100, no. 13: 1429-1445.

Research article
Published: 03 July 2019 in International Journal of Analytical Chemistry
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Multiwalled carbon nanotube (MWCNT) was fixed onto the surface of a magnetic silica ([email protected]) substrate via chemical vapour deposition (CVD). Acetylene gas was used as the carbon source and cobalt oxide as the catalyst. The chemical and physical characteristics of the materials were investigated by transmission electron microscopy (TEM), Raman spectroscopy (RS), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and nitrogen adsorption/desorption isotherm. The synthesized [email protected] nanocomposite was used as a magnetic solid phase extraction (MSPE) adsorbent for the preconcentration of organophosphorus pesticides (OPPs), specifically, azinphos methyl, chlorpyrifos, parathion, and malathion. The factors influencing the extraction efficiency such as pH, contact time, and adsorbent dosage were investigated and optimized by response surface methodology (RSM) and desirability function. Linear response was obtained in the concentration range of 10–200 μg/L for the analytes with determination coefficients ranging between 0.9955 and 0.9977. The limits of detection (LODs) and quantification (LOQs) were in the range of 0.004-0.150 μg/L and 0.013-0.499 μg/L, respectively. [email protected] was applied in the extraction and subsequent determination of OPPs in water samples from Vaal River and Vaal Dam with recoveries ranging from 84.0 to 101.4% (RSDs = 3.8–9.6%, n = 3) in Vaal River and 86.2 to 93.8% (RSDs = 2.9–10.4%, n = 3) in Vaal Dam. The obtained results showed that the newly synthesized [email protected] nanocomposite can be an efficient adsorbent with good potential for the preconcentration and extraction of selected OPPs from aqueous media.

ACS Style

Veronica W. O. Wanjeri; Sefater Gbashi; Jane C. Ngila; Patrick Njobeh; Messai A. Mamo; Patrick G. Ndungu. Chemical Vapour Deposition of MWCNT on Silica Coated Fe3O4 and Use of Response Surface Methodology for Optimizing the Extraction of Organophosphorus Pesticides from Water. International Journal of Analytical Chemistry 2019, 2019, 1 -16.

AMA Style

Veronica W. O. Wanjeri, Sefater Gbashi, Jane C. Ngila, Patrick Njobeh, Messai A. Mamo, Patrick G. Ndungu. Chemical Vapour Deposition of MWCNT on Silica Coated Fe3O4 and Use of Response Surface Methodology for Optimizing the Extraction of Organophosphorus Pesticides from Water. International Journal of Analytical Chemistry. 2019; 2019 ():1-16.

Chicago/Turabian Style

Veronica W. O. Wanjeri; Sefater Gbashi; Jane C. Ngila; Patrick Njobeh; Messai A. Mamo; Patrick G. Ndungu. 2019. "Chemical Vapour Deposition of MWCNT on Silica Coated Fe3O4 and Use of Response Surface Methodology for Optimizing the Extraction of Organophosphorus Pesticides from Water." International Journal of Analytical Chemistry 2019, no. : 1-16.

Chemical routes to materials
Published: 03 July 2019 in Journal of Materials Science
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Presented herein is the nitrogen-doped multiwalled carbon nanotubes (N-MWCNTs) production from a residue, sugarcane bagasse, using 1-butyl-3-methylimidazolium chloride [C4MIM]Cl as the solvent and nitrogen source, and ferrocene as the catalyst source. N-MWCNTs were synthesised using the floating catalyst chemical vapour deposition method at 850 °C. The synthesised N-MWCNTs were characterised using transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), X-ray diffraction (XRD) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. Hollow tubular structures of N-MWCNTs were observed using TEM. These observations correlated morphology from SEM which showed spaghetti-like structures, and also EDS detected the presence of nitrogen. Raman spectroscopy indicated MWCNT bands, around 1350 and 1580 cm−1 assigned to D-band and G-band due to defective and graphitic carbon vibrations, respectively. Also, XRD patterns showed typical N-MWCNT structures with a strong intensity peak at 2θ = 26.4° which was indexed as the C(002) reflection of graphite. TGA showed an N-CNTs thermogram curve, with the main decomposition temperature around 590 °C. The study showed that N-MWCNTs were successfully synthesised from sugarcane bagasse. The study significantly establishes a strategy for utilisation and value addition of a residue which is abundant from sugar production mills.

ACS Style

Kudzai Mugadza; Patrick G. Ndungu; Annegret Stark; Vincent O. Nyamori. Conversion of residue biomass into value added carbon materials: utilisation of sugarcane bagasse and ionic liquids. Journal of Materials Science 2019, 54, 12476 -12487.

AMA Style

Kudzai Mugadza, Patrick G. Ndungu, Annegret Stark, Vincent O. Nyamori. Conversion of residue biomass into value added carbon materials: utilisation of sugarcane bagasse and ionic liquids. Journal of Materials Science. 2019; 54 (19):12476-12487.

Chicago/Turabian Style

Kudzai Mugadza; Patrick G. Ndungu; Annegret Stark; Vincent O. Nyamori. 2019. "Conversion of residue biomass into value added carbon materials: utilisation of sugarcane bagasse and ionic liquids." Journal of Materials Science 54, no. 19: 12476-12487.

Journal article
Published: 14 June 2019 in Water
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The present study evaluated the effectiveness of Fe-Mn modified kaolin clay in the uptake of As(V) from the solution. The elemental composition was characterized using X-ray fluorescence (XRF), while the surface morphology was characterized using Scanning Electron Microscopy (SEM). The surface area, pore diameter, and pore volume were determined using Brunauer, Emmett, and Teller (BET) and Barrett-Joyner-Halenda (BJH) techniques. The efficiency of the Arsenic removal of the adsorbent was evaluated using batch experiments. The results showed that the percentage of As(V) removal is optimum at acidic pH and decreased as the solution pH becomes more alkaline. The adsorption kinetics data fitted better to pseudo-second-order compared to the pseudo-first-order of reaction kinetics. The adsorption isotherm data fitted to the Langmuir isotherm model showing a maximum adsorption capacity of 2.44 mg/g, adsorbate concentration range of 1–30 mg/L, and adsorbent dosage of 0.4 g/100 mL. The value of ∆G° of the thermodynamic parameter was found to be negative, while ∆H° and ∆S° were found to be positive. For the regeneration-reuse study, the percentage of removal was found to be >85% after the sixth cycle of reuse. The results obtained from this study showed that Fe-Mn modified kaolin (FMK) is suitable for use in the uptake of As(V) from groundwater.

ACS Style

Rabelani Mudzielwana; Mugera Wilson Gitari; Patrick Ndungu. Uptake of As(V) from Groundwater Using Fe-Mn Oxides Modified Kaolin Clay: Physicochemical Characterization and Adsorption Data Modeling. Water 2019, 11, 1245 .

AMA Style

Rabelani Mudzielwana, Mugera Wilson Gitari, Patrick Ndungu. Uptake of As(V) from Groundwater Using Fe-Mn Oxides Modified Kaolin Clay: Physicochemical Characterization and Adsorption Data Modeling. Water. 2019; 11 (6):1245.

Chicago/Turabian Style

Rabelani Mudzielwana; Mugera Wilson Gitari; Patrick Ndungu. 2019. "Uptake of As(V) from Groundwater Using Fe-Mn Oxides Modified Kaolin Clay: Physicochemical Characterization and Adsorption Data Modeling." Water 11, no. 6: 1245.

Journal article
Published: 05 June 2019 in Materials Chemistry and Physics
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Carbon nanostructured materials (CNMs) have vast capability in the field of energy, for storage and conversion purposes. Consequently, extensive greener and environmentally benign synthesis techniques that employ natural and readily renewable, low-cost waste materials need to be established. Herein, cellulose is considered as an alternative precursor source for the synthesis of CNMs. In the past decade, ionic liquids (ILs) have exhibited a great potential in a diverse number of applications. However, insignificant attention has been paid to the structure of ILs in relation to their extended application as a media for the dissolution of cellulose to avail carbon for CNMs synthesis. As baseline, a number of ionic liquids were used as carbon sources for CNM production, and distinct differences were found, depending on the type of ionic liquid used and the temperature of synthesis. Furthermore. CNMs were fabricated using a combination of the ionic liquid, 1-butyl-3-methylimidazolium chloride, [C4MIM]Cl, and cellulose, in the presence of ferrocene as catalyst precursor, using the floating catalyst chemical vapour deposition technique. Typical spaghetti like, hollow tubular structures with bamboo compartments, resembling N-doped multiwalled tubular carbon nanomaterials were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) respectively. Thermal stability studies showed thermogram profiles with a stability of around 550 °C. The sample synthesised with cellulose was more stable than the sample synthesised from IL and ferrocene only. Characteristic D- and G-bands were observed around 1380 and 1560 cm−1, respectively, for Raman spectroscopy. X-ray diffraction (XRD) showed characteristic tubular carbon nanomaterials and or graphitic/N-graphitic diffraction patterns.

ACS Style

Kudzai Mugadza; Patrick G. Ndungu; Annegret Stark; Vincent O. Nyamori. Ionic liquids and cellulose: Innovative feedstock for synthesis of carbon nanostructured material. Materials Chemistry and Physics 2019, 234, 201 -209.

AMA Style

Kudzai Mugadza, Patrick G. Ndungu, Annegret Stark, Vincent O. Nyamori. Ionic liquids and cellulose: Innovative feedstock for synthesis of carbon nanostructured material. Materials Chemistry and Physics. 2019; 234 ():201-209.

Chicago/Turabian Style

Kudzai Mugadza; Patrick G. Ndungu; Annegret Stark; Vincent O. Nyamori. 2019. "Ionic liquids and cellulose: Innovative feedstock for synthesis of carbon nanostructured material." Materials Chemistry and Physics 234, no. : 201-209.

Journal article
Published: 09 May 2019 in Journal of Marine Science and Engineering
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This work reports the preparation and application of Fe2O3-SiO2-PAN nanocomposite for the removal of Cr3+, Cu2+, Al3+, Ba2+, Zn2+, Ni2+, Mn2+, Co2+, and Ti3+ from seawater. X-ray diffraction (XRD), scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscope (TEM), and Brunauer-Emmett-Teller (BET) characterized the synthesized composite. The following experimental parameters (Extraction time, adsorbent mass and pH) affecting the removal of major and trace metals were optimized using response surface methodology (RSM). The applicability of the RSM model was verified by performing the confirmation experiment using the optimal condition and the removal efficiency ranged from 90% to 97%, implying that the model was valid. The adsorption kinetic data was described by the pseudo-second order model. The applicability of the materials was tested on real seawater samples (initial concentration ranging from 0.270–203 µg L−1) and the results showed satisfactory percentage efficiency removal that range from 98% to 99.9%. The maximum adsorption capacities were found to be 4.36, 7.20, 2.23, 6.60, 5.06, 2.60, 6.79, 6.65 and 3.00 mg g−1, for Cr3+, Cu2+, Al3+, Ba2+, Zn2+, Ni2+, Mn2+, Co2+, and Ti4+, respectively.

ACS Style

Denga Ramutshatsha-Makhwedzha; Jane Catherine Ngila; Patrick Ndungu; Philiswa Nosizo Nomngongo. Ultrasound Assisted Adsorptive Removal of Cr, Cu, Al, Ba, Zn, Ni, Mn, Co and Ti from Seawater Using Fe2O3-SiO2-PAN Nanocomposite: Equilibrium Kinetics. Journal of Marine Science and Engineering 2019, 7, 133 .

AMA Style

Denga Ramutshatsha-Makhwedzha, Jane Catherine Ngila, Patrick Ndungu, Philiswa Nosizo Nomngongo. Ultrasound Assisted Adsorptive Removal of Cr, Cu, Al, Ba, Zn, Ni, Mn, Co and Ti from Seawater Using Fe2O3-SiO2-PAN Nanocomposite: Equilibrium Kinetics. Journal of Marine Science and Engineering. 2019; 7 (5):133.

Chicago/Turabian Style

Denga Ramutshatsha-Makhwedzha; Jane Catherine Ngila; Patrick Ndungu; Philiswa Nosizo Nomngongo. 2019. "Ultrasound Assisted Adsorptive Removal of Cr, Cu, Al, Ba, Zn, Ni, Mn, Co and Ti from Seawater Using Fe2O3-SiO2-PAN Nanocomposite: Equilibrium Kinetics." Journal of Marine Science and Engineering 7, no. 5: 133.

Review article
Published: 07 May 2019 in Environmental Research
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The importance of improving adsorbent's adsorption efficiency in organic pollutants has been reported by many researchers. Surfactant-based modified adsorbents were a tasteful choice. As a result, the use of surfactants as a modifier for removing organic pollutants has shown to play a very big role in enhancing the adsorption efficiency of different materials. Ionic liquids are receiving extensive interest as green multipurpose compounds, primarily as a replacement for traditional chemicals that are used in many chemical processes. This work gives a brief bibliometric analysis of application of ionic liquid from 1930 to 2017, documents were collected from Scopus database and keywords from the abstracts and titles were analyzed using VOSviewer software. Furthermore, the work presents a review of conventionally known surfactants and the recent likelihood of ionic liquids for modifying adsorbents for adsorption of organic pollutants. Over the period of years between 1930 and 2017, 13,144 documents were published on the application of ionic liquids. VOSviewer software further confirms that adsorption is one of the leading areas in applications of ionic liquids. Review also showed that ionic liquid is a good modifier of adsorbents.

ACS Style

Isiaka A. Lawal; Michael Klink; Patrick Ndungu; Brenda Moodley. Brief bibliometric analysis of “ionic liquid” applications and its review as a substitute for common adsorbent modifier for the adsorption of organic pollutants. Environmental Research 2019, 175, 34 -51.

AMA Style

Isiaka A. Lawal, Michael Klink, Patrick Ndungu, Brenda Moodley. Brief bibliometric analysis of “ionic liquid” applications and its review as a substitute for common adsorbent modifier for the adsorption of organic pollutants. Environmental Research. 2019; 175 ():34-51.

Chicago/Turabian Style

Isiaka A. Lawal; Michael Klink; Patrick Ndungu; Brenda Moodley. 2019. "Brief bibliometric analysis of “ionic liquid” applications and its review as a substitute for common adsorbent modifier for the adsorption of organic pollutants." Environmental Research 175, no. : 34-51.

Journal article
Published: 06 May 2019 in Journal of Molecular Liquids
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The removal of phenol and crystal violet dye using carbon nanotubes (CNTs) modified with deep eutectic solvent (DES) was investigated. DES (mixture of methyltriphenylphosphonium bromide and glycerol) was prepared and characterized by nuclear magnetic resonance (1H and 13C NMR). The DES was thereafter used to modify CNTs to form CNT–DES. The modified CNTs and CNTs only were characterized using FT–IR, scanning electron microscopy (SEM), and X-ray diffraction (XRD) and used in the adsorption study of phenol (PHE) and crystal violet dye (CRV). The effects of adsorbates concentration, solution pH and contact time were investigated in order to determine optimal experimental conditions. Adsorption data was better described by the pseudo-second-order kinetics and Freundlich isotherm for both CRV and PHE on CNTs and CNT–DES. Computational modelling was used to explain the possible adsorption interactions of CNT and CNT–DES with CRV and PHE, respectively. The modified moiety was better than CNT only for the adsorption of these compounds, which is in agreement with experimental outcome.

ACS Style

Isiaka Lawal; Monsurat M. Lawal; Mayowa A. Azeez; Patrick Ndungu. Theoretical and experimental adsorption studies of phenol and crystal violet dye on carbon nanotube functionalized with deep eutectic solvent. Journal of Molecular Liquids 2019, 288, 110895 .

AMA Style

Isiaka Lawal, Monsurat M. Lawal, Mayowa A. Azeez, Patrick Ndungu. Theoretical and experimental adsorption studies of phenol and crystal violet dye on carbon nanotube functionalized with deep eutectic solvent. Journal of Molecular Liquids. 2019; 288 ():110895.

Chicago/Turabian Style

Isiaka Lawal; Monsurat M. Lawal; Mayowa A. Azeez; Patrick Ndungu. 2019. "Theoretical and experimental adsorption studies of phenol and crystal violet dye on carbon nanotube functionalized with deep eutectic solvent." Journal of Molecular Liquids 288, no. : 110895.

Journal article
Published: 17 April 2019 in Journal of Environmental Chemical Engineering
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In this study, the use of acid mine drainage as alternative source of ferric ion for the synthesis of iron nanoparticles was investigated. The physical and chemical characteristics of acid mine drainage from Navigation coal mine and the West Rand mine, South Africa were conducted. The synthesised iron nanoparticles were compared with iron nanoparticles prepared from commercial reagents by x-ray diffraction, x-ray fluorescence, scanning electron microscopy, high resolution transmission electron microscopy and Brunauer-Emmett-Teller surface area determination. The iron nanoparticles were utilised for the treatment of acid mine drainage. Experimental results showed that the characteristics of acid mine drainage samples differ from site to site due to the differences in their geological composition, chemical deposition, rate of oxidation, and availability of pyrite ores. The Toeseep acid mine drainage feedstock from Navigation coal mine was found to contain the highest concentration of iron (4,219.14 mg L−1) thus; it was regarded to be a suitable source of iron, sulphate (21,317.79 mg L−1) was the predominant anion. The synthesized iron nanoparticles were crystalline and spherical in shape, with average particle size of 31.8 nm or 28.05 nm and Brunauer-Emmett-Teller surface area of 88 ± 3.16 m2 g−1 or 91 ± 3.08 m2 g−1 for the iron nanoparticles synthesized from acid mine drainage or ferric chloride, respectively. The optimisation of the iron nanoparticles dosage and contact time for the treatment of Navigation Toeseep acid mine drainage was determined to be 0.1 g and 60 min, respectively. The toxic elements in the raw acid mine drainage were removed with over 75% efficiency.

ACS Style

M.J. Alegbe; O.S. Ayanda; P. Ndungu; A. Nechaev; O.O. Fatoba; L.F. Petrik. Physicochemical characteristics of acid mine drainage, simultaneous remediation and use as feedstock for value added products. Journal of Environmental Chemical Engineering 2019, 7, 1 .

AMA Style

M.J. Alegbe, O.S. Ayanda, P. Ndungu, A. Nechaev, O.O. Fatoba, L.F. Petrik. Physicochemical characteristics of acid mine drainage, simultaneous remediation and use as feedstock for value added products. Journal of Environmental Chemical Engineering. 2019; 7 (3):1.

Chicago/Turabian Style

M.J. Alegbe; O.S. Ayanda; P. Ndungu; A. Nechaev; O.O. Fatoba; L.F. Petrik. 2019. "Physicochemical characteristics of acid mine drainage, simultaneous remediation and use as feedstock for value added products." Journal of Environmental Chemical Engineering 7, no. 3: 1.

Original article
Published: 13 March 2019 in Environmental Earth Sciences
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Organochlorinated pesticide (OCP) concentrations were evaluated in sediment, soil and surface water of the Msunduzi River as well as the influent, effluent and biosolids from the Darvill wastewater treatment plant (WWTP) of Pietermaritzburg, South Africa. Samples were extracted with dichloromethane using an ultra-sonication method, and cleaned up using multilayered silica gel and analysed using gas chromatography-mass spectrometry. The results showed that all 13 selected OCPs were detected in all the environmental media as well as in the wastewater treatment plant samples. The results revealed that the OCP concentrations along the sites varied based on the anthropogenic activities of the area. The influent of the Darvill WWTP and Du Toit (DUT) site were found to be the most polluted sites. The results from the winter sampling showed highest concentrations of OCPs compared to the spring season. Sediment was found to contain significant amounts of all the selected OCPs with water samples containing the lowest concentrations for both winter and spring seasons. Among the OCPs evaluated, dichlorodiphenyltrichloroethane (DDT) and its metabolites were predominant in all.

ACS Style

Gbadebo Clement Adeyinka; Brenda Moodley; Grace Birungi; Patrick Ndungu. Evaluation of organochlorinated pesticide (OCP) residues in soil, sediment and water from the Msunduzi River in South Africa. Environmental Earth Sciences 2019, 78, 223 .

AMA Style

Gbadebo Clement Adeyinka, Brenda Moodley, Grace Birungi, Patrick Ndungu. Evaluation of organochlorinated pesticide (OCP) residues in soil, sediment and water from the Msunduzi River in South Africa. Environmental Earth Sciences. 2019; 78 (6):223.

Chicago/Turabian Style

Gbadebo Clement Adeyinka; Brenda Moodley; Grace Birungi; Patrick Ndungu. 2019. "Evaluation of organochlorinated pesticide (OCP) residues in soil, sediment and water from the Msunduzi River in South Africa." Environmental Earth Sciences 78, no. 6: 223.

Journal article
Published: 22 February 2019 in International Journal of Environmental Research and Public Health
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In this study, aluminosilicate rich clay soils were prepared through mechanochemical activation. The chemical and mineralogical properties were investigated using X-Ray Fluorescence (XRF) and X-ray diffraction (XRD). The functional groups, morphology and surface area were evaluated using Fourier Transform Infra-Red (FTIR), Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. Batch experiments were used to evaluate its defluoridation efficiency while antibacterial activities were assessed using well diffusion method. Maximum adsorption capacity was found to be 1.87 mg/g with 32% fluoride removal. Fluoride adsorption was found to reduce in the presence of Cl−, PO42− and CO32− while it increased in the presence of SO42− and NO3−. Adsorption data fitted well to Freundlich isotherms, hence, confirming heterogeneous multilayer adsorption. Kinetic studies revealed that fluoride adsorption fitted well to pseudo-second order model. The sorption of F− onto the clays’ surface followed intra-particle diffusion mode. High correlation coefficient indicates that the sorption process was greatly controlled by particle diffusion while it is minimal in pore diffusion model. Antibacterial studies revealed no zone of inhibition for all the activated clays, hence indicating that they are not active against the bacterial strains of Escherichia coli used in this study. The results showed activated clays’ potential for defluoridation. Its effectiveness in pathogen removal is limited. Hence further modifications of the clays’ surfaces are hereby recommended.

ACS Style

Olumuyiwa A. Obijole; Mugera W. Gitari; Patrick G. Ndungu; Amidou Samie. Mechanochemically Activated Aluminosilicate Clay Soils and their Application for Defluoridation and Pathogen Removal from Groundwater. International Journal of Environmental Research and Public Health 2019, 16, 654 .

AMA Style

Olumuyiwa A. Obijole, Mugera W. Gitari, Patrick G. Ndungu, Amidou Samie. Mechanochemically Activated Aluminosilicate Clay Soils and their Application for Defluoridation and Pathogen Removal from Groundwater. International Journal of Environmental Research and Public Health. 2019; 16 (4):654.

Chicago/Turabian Style

Olumuyiwa A. Obijole; Mugera W. Gitari; Patrick G. Ndungu; Amidou Samie. 2019. "Mechanochemically Activated Aluminosilicate Clay Soils and their Application for Defluoridation and Pathogen Removal from Groundwater." International Journal of Environmental Research and Public Health 16, no. 4: 654.