Wilson Gitari

Wilson Gitari
The Technical University of Kenya · Department of Chemical Sciences and Technology

PhD

About

155
Publications
49,154
Reads
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2,528
Citations
Citations since 2016
72 Research Items
1918 Citations
20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
Introduction
My research focuses on development of Environmental inspired Technologies in combination with Analytical Chemistry tools for Natural Resources Management. My philosophy of teaching center’s on imparting analytical skills to my students and preparing them to use their skills for solving problems within their communities and their environment. I have developed a strong teaching and research portfolio over 15 years of working in tertiary institutions in Africa.
Additional affiliations
December 2016 - June 2017
School of Environmental Sciences,University of Venda
Position
  • Professor
April 2013 - present
University of Venda
Position
  • Professor (Associate)
Description
  • Teaching and Research
January 2010 - March 2013
University of Venda
Position
  • Professor (Associate)
Description
  • Teaching and Research

Publications

Publications (155)
Article
Full-text available
A new, fast and efficient method, hyphenated microwave-assisted aqueous two-phase extraction (MA-ATPE) was applied in the extraction of α-solanine from Solanum retroflexum. This environmentally friendly extraction method applied water and ethanol as extraction solvents. Central composite design (CCD) was performed which included numerical parameter...
Article
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The Benue Trough Basin (BTB) of Nigeria is geologically and geo-morphologically subdivided into upper, middle, and lower segments. The BTB is the subject of geological research due to its rich coal deposits that have the potential for oil and gas. The purpose of the present study is to examine the origins, depositional environments, and thermal his...
Article
This study presents the synthesis of cerium doped poly(−para-phenylenediamine) composite (Ce-pPD) using chemical co-oxidative polymerization and evaluates its potential towards F־, As³⁺, and pathogens removal from aqueous solution. The Scanning Electron Microscope, Fourier Transform Infra-red, X-ray Diffraction, Brunauer Emmett Teller, and CHNS/O o...
Article
Full-text available
An innovative and sustainable approach to integrating modified Ag–MgO–nanohydroxyapatite on a nanofibrous cellulose template (CNF-AgMgOnHaP) as a multifunctional adsorbent via a hydrothermal bioreduction route using Citrus paradisi peel extract was developed and examined. The surface morphology and mineralogical properties of CNF-AgMgOnHaP by UV–vi...
Article
Full-text available
This paper presents the potential application of macadamia nut shells (MNS) in the bio-sorption of fluoride and its antimicrobial potency against common pathogens encountered in surface water resources. The efficiency of MNS in the sorption of fluoride was determined using batch mode experiments, while the antimicrobial potency was investigated usi...
Article
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The biomass Solanum mauritianum ( S. mauritianum ) is an invasive weed specie; however, it is a source of medicinally important metabolites, as reported in literature, such as solasonine and solamargine. The study was directed at the optimization of microwave and aqueous two-phase-based extraction techniques which involved microwave-assisted extrac...
Article
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Solanum plants (Solanaceae) are renowned source of nutraceuticals and have widely been explored for their phytochemical constituents. This work investigated the effects of kosmotropic and chaotropic salts on the number of phytochemicals extracted from the leaves of a nutraceutical plant, Solanum retroflexum, and analyzed on the ultra-performance li...
Article
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For the first time ultra-violet (UV)-fluorescent metabolites were obtained via aqueous two phase extraction (ATPE) from Solanum retroflexum (S. retroflexum). Of the compounds simultaneously extracted via ATPE, nine UV-fluorescent compounds were identified. Using thin layer chromatography (TLC) and ultra high performance liquid chromatography quadru...
Preprint
Full-text available
Aqueous two phase extraction (ATPE) was applied in the extraction of an allelochemical, solasodine, from an invasive plant, Solanum mauritianum . Central composite design was performed which included numerical parameters such as time and mass of plant powder. The categorical factors included the type of salt used in aiding extraction such as the ch...
Article
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Carbonaceous shale is more topical than ever before due to the associated unconventional resources of methane. The use of FTIR, SEM-EDX, and mineralogical analyses has demonstrated a promising approach to assess methanogenesis potentials in a more rapid and reliable manner for preliminary prospecting. Representative core samples from the borehole t...
Article
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In the present study, silver nanoparticles (AgNPs) were synthesized using both the chemical and biological methods and conjugated with Pyrenacantha grandiflora extracts. These were then characterized and evaluated for antimicrobial activities against multi-drug resistant pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA), Klebsie...
Article
A clay based composite adsorbent for fluoride was fabricated by blending the locally available smectite rich clay and MnO2 coated bentonite clay. The efficiency of the material towards fluoride adsorption was evaluated using fixed-bed column experiments. The results from column experiments showed that increasing parameters such as bed height and in...
Article
Full-text available
This work evaluated the extraction efficiency of silica from diatomaceous earth (DE) by conventional solvent extraction (CSE) and ultrasound-assisted extraction (UAE) under basic and acidic (HCl) conditions utilizing response surface methodology (RSM). A common statistical model was used to get the best percentage yield and percentage purity using...
Article
Full-text available
Water is regarded as an important natural resource to sustain life, and its purification is an important criterion that determines its quality and usefulness. In this study, the incorporation of Fe3+ oxide onto a phenylenediamine (pPD) polymer matrix through chemical co-polymerization was prepared, and its arsenite and fluoride removal potentials a...
Article
Biopolymers are renowned for their sustainable, biodegradable, biocompatible and most of them have antitoxic characteristics. These versatile naturally derived compounds include proteins, polynucleotides (RNA and DNA) and polysaccharides. Cellulose and chitosan are the most abundant polysaccharides. Proteins and polysaccharides have been applied as...
Article
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This work reports the synthesis of 3-bromo-benzimidazolone using melt condensation, its polymerization and functionalization on silica which was extracted from diatomaceous earth in our previous work. The synthesized compounds were characterized using FTIR, NMR, SEM-EDS and TEM. The FTIR and NMR spectra of the synthesized benzimidazolones showed th...
Article
Full-text available
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...
Article
The rare earth elements (REE) possess a beneficial combination of chemical and physical properties, making them valuable for most advanced branches of engineering and technology. Alternative sources of REE are desirable due to limited reserves of conventional REE containing minerals over the world combined with disproportionate supply over demand i...
Article
Antibiotic residues have become a major concern worldwide as food contaminants due to the risk that they may pose to human health. The presence of these residues in food is due to improper veterinary practices. Consequently, rapid and cost-effective clean-up methods prior to analysis for these residues in food matrices are increasingly becoming nec...
Article
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The severity of oil pollution, brought about by improper management, increases daily with an increase in the exploration and usage of oil, especially with an increase in industrialization. Conventional oil treatment methods are either expensive or time consuming, hence the need for new technologies. The aim of this research is to synthesize polypyr...
Article
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The chemical reactions of dry-disposed ash dump, ingressed oxygen, carbon dioxide, and infiltrating rainwater affect mineralogical transformation, redistribution, and migration of chemical species. Composite samples of weathered coal fly ash taken at various depths and fresh coal fly ash were examined using organic petrographic, X-ray diffraction,...
Article
Full-text available
Acetylated materials have been applied successfully in oily water remediation with some degree of success. Many of these materials which have been acetylated are, however, from seasonal fruits and other plant parts. This work reports the successful acetylation of silica extracted from diatomaceous earth by refluxing silica and acetic anhydride usin...
Article
Full-text available
Some antibiotics have lost their efficacy over common infections and this has led to the search for new antibiotics and chemically altering existing ones for a better control of infectious diseases. In the present study, Pyrenacantha grandiflora tubers extracts were conjugated with ampicillin, penicillin, vancomycin and silver nanoparticles and the...
Article
Full-text available
Studies were conducted to determine if crystalline zeolites could be obtained from the filtrates of coal fly ash (CFA)/NaOH slurries through sonication. The CFA/NaOH slurries were obtained by aging CFA in 3 M NaOH for 24 h at 50°C using a solid/ liquid (S/L) ratio of 15 g/120 mL. FT-IR studies indicated that the 'Lo' regime ultrasonicated zeolite h...
Article
This study examined the sol-gel biosynthesis of metal-metal oxide nanoparticles impregnated on a chitosan polymer backbone ([email protected]) and its potential application in removing fluoride and pathogens simultaneously from groundwater. The formation of the nano-adsorbent from the different surface functionalization precursors and phases were s...
Chapter
Full-text available
The greatest challenge facing many governments is the improvement of the level of socioeconomic development in their respective countries and providing better life. Clean and sustainably generated energy, renewable energy, could be the only hope in underpinning the global millennium development goals. Many of the rural communities in developing cou...
Article
Full-text available
In this study, a hybrid arsenic adsorbent was synthesized through intercalation inorganic and organic surfactant cations onto kaolin clay interlayers. The synthesized adsorbent was characterized X-ray fluorescence (XRF), Fourier Transform Infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET). Batch studi...
Article
Full-text available
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...
Article
Full-text available
In this paper surfactant modified kaolin clay for As(III) and As(V) was prepared by intercalating hexadecyltrimethylamonium bromide (HDTMA-Br) cationic surfactant onto the clay interlayers. Batch experiments were used to evaluate the effectiveness of surfactant modified kaolin clay towards As(III) and As(V) removal. The results revealed that adsorp...
Article
Full-text available
This study focuses on time-dependent microwave-assisted biosynthesis of silver nanoparticles using aqueous peel extracts of Citrus paradisi as a reducing, stabilizing and capping agent with emphasis on its antibacterial property. Optical, structural and morphological properties of the synthesized Citrus paradisi peel extract silver nanoparticle (CP...
Article
Full-text available
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 us...
Article
Full-text available
Abandoned gold mine sites are generally characterised by severe environmental problems and physical hazards. Because of socio-economic problems confronting communities around abandoned mine sites, historic and abandoned gold mines have become hot-spots for artisanal and small-scale miners. These mining activities at times thwart the efforts of reha...
Article
Full-text available
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 microsc...
Article
Full-text available
The deterioration of water quality is a serious concern for a water scarce‐country like South Africa (SA). This article looks at the risks posed by the common practice of using surface waters to irrigate crops, as these are usually contaminated with harmful cyanobacteria and cyanotoxins which can be bio‐accumulated by plants. In addition to cyanoto...
Article
Full-text available
This study evaluated the physicochemical and mineralogical properties, mobile chemical species bioavailability and translocation in Brassica juncea and Spinacea oleracea L. plants of a South African coal-fired power utility. Coal-fly-ash (CFA) disposal is associated with various environmental and health risks, including air, soil, surface, and grou...
Article
Full-text available
The economic benefits of mining industry have often overshadowed the serious challenges posed to the environments through huge volume of tailings generated and disposed in tailings dumps. Some of these challenges include the surface and groundwater contamination, dust, and inability to utilize the land for developmental purposes. The abandoned copp...
Article
This study evaluates the adsorptive properties of locally available alumino-silicate clay in removal of As(III) and As(V) from groundwater. Physicochemical properties of the clay were characterized using x-ray diffraction (XRD), x-ray fluorescence (XRF), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) technique...
Preprint
Full-text available
This study evaluated the physicochemical, mineralogical properties, mobile chemical species’ bioavailability and translocation in Brassica juncea and Spinacea oleracea L plants of a South African coal fired power utility. Coal fly ash (CFA) disposal is associated with various environmental and health risks including air, soil, surface and ground wa...
Conference Paper
Full-text available
In this study, aluminosilicate rich clay soils were prepared through mechanochemical activation. The chemical and mineralogical properties were investigated using XRF and XRD. The functional groups, morphology and the surface area were evaluated using FTIR, SEM and BET. Batch experiments were used to assess defluoridation efficiency of the activate...
Article
Full-text available
High concentrations of fluoride in drinking water are reported to be hazardous to human health. This study was conducted to assess the efficiency of mechanochemically-activated aluminosilicate clay soil in removing fluoride from groundwater. The soil was subjected to physicochemical transformation through mechanochemical activation for different ti...
Preprint
Full-text available
The continued application of organochlorine pesticides (OCPs) in indoor residual spraying has posed significant threat to human health in Northern part of South Africa, despite its ban. In this study, we investigated the occurrence and spatial distribution of DDTs and its metabolites in surface soil (30 samples) collected in and around the spray ho...
Article
The paper presents a facile green method of synthesizing a multi-functional 3-layered Ag-MgO/nanohydroxyapatite (Ag-MgOnHaP) composite via a combined microwave and ultrasonically modified methods with emphasis on simultaneous pathogens and fluoride removal in groundwater. The reduction of Ag and MgO ions by aqueous Citrus paradisi peel extracts was...
Article
Full-text available
Large volumes of disposed mine tailings abound in several regions of South Africa, as a consequence of unregulated, unsustainable long years of mining activities. Tailings dumps occupy a large volume of valuable land, and present a potential risk for aquatic systems, through leaching of potentially toxic chemical species. This paper reports on the...
Article
Full-text available
Results of geochemical investigation of shale and claystone samples from two different sections of the exposed Ahoko claystone-shale sequence along the Koton-Karifi/Abaji highway are presented and discussed. Chemical variation of SiO2/Al2O3 and Na2O/K2O is ascribed to varying degrees of weathering of plagioclase rich rock either at the source and/o...
Chapter
Full-text available
More than half of the Sustainable Development Goals’ (SDGs) target group are rural poor dwellers from developing countries, particularly in Asia and Africa, who normally live on subsistence agriculture. Thus, securing a productive and profitable agricultural sector for the rural areas becomes a fundamental component in accelerating the achievement...
Article
Full-text available
A low-cost adsorbent produced from Mn2+-modified bentonite clay was evaluated for groundwater defluoridation. Batch experiments were used to evaluate the effect of contact time at various adsorbent dosages, adsorption isotherms and the effect of pH on fluoride removal. The results showed that the optimum F- uptake occurred within the first 30 min c...