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Recent Submissions
Green Synthesis of Indium Tin Oxide Nanoparticles from Herbal Extracts for Photocatalytic Dye Degradation
(Mount Kenya University, 2025) Osemba, Martin; Maghanga, Justin; Ojwang, Loice
Increased emission of harmful and non-biodegradable dyes from industries poses threats to
living organisms, thus the need for sustainable effluent treatment methods. This study
embarked on a green approach to synthesize indium tin oxide (ITO) nanoparticles applying
herbal extracts of the leaves to act as bio-reducing and stabilizing agents. This bio-assisted
synthesis discourages the utilization of chemicals that could be toxic. The ITO nanoparticles
synthesized showed a cubic bixbyite crystalline structures having been successfully
incorporated Sn⁴⁺ ions the lattice In₂O₃, confirmed by XRD analysis. TEM revealed nanoscale
and quasi-spherical components with some agglomeration attributed of surface interactions
by the phytochemical. FTIR analysis indicated retention of bio-organic functional groups in
the regions of 3200 - 3500 cm-1
corresponding to the O-H stretching vibrations of phenolic
compounds and alcohol groups. At 1630-1650 cm-1 have C=O stretching vibrations of amide
and carbonyl groups while peaks at 1380-1450 cm-1
are aromatic C-C stretching and C-N
vibrations that partially interacted with the nanoparticle surface thus contributed to an
enhanced stability on the surface and interfacial transfer of charge. From the Optical studies
there was an improved absorption of light and a modification of band gap of 3.83 eV, where
PL analysis suggested a suppression in the recombination of electron–hole. The performance
of photocatalytic activity by the green-synthesized indium tin oxide nanoparticles was
determined utilizing MB dye model by light irradiation. These nanoparticles illustrated
efficiency in dye degradation by pseudo-first-order kinetics, showing enhanced performance
attribution of increased SA, oxygen vacancies, Sn doping, and bio-induced defect surfaces.
The proposed mechanism involved the production of reactive oxygen, OH and superoxide
species, resulting in the mineralization of dye components. Overall, this study highlighted the
potentiality in extract-mediated green synthesis as an alternative path in production efficiency
of ITO photo-catalysts and by extension their applications other than just conventionally
optoelectronic uses for the environmentally friendly effluent removal technologies.
Silver Nanoparticle Elecrocatalyst Embedded onto Indium Tin Oxide Electrodes for Degradation of Azo Dyes
(Mount Kenya University, 2026-01-15) Osemba, Martin Ouma; Karenga, Samuel; Keru, Godffrey
The research was conducted to establish the effectiveness of silver
nanoparticles embedded in indium tin oxide (ITO) thin film conducting
material in causing the textile azo dye effluent degradation. The percentages of
azo dye degradation were as follows: 68.4%, 72.5% and 93.1% using
electrocoagulation, ITO and ITO-AgNPs coupled electrodes, respectively. The
results obtained from the two-factor ANOVA with replication indicated a
significant difference (p = 0.0024) when the silver nanoparticles embedded on
indium tin oxide electrodes were utilised in the degradation of these azo dyes
in the effluent samples. The colour removal was 99.97% showing that the
optimised process was effective and efficient in the degradation of these azo
dyes in the textile wastewaters.
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AI-Powered Mobile Proctoring Frameworks using Machine Learning Algorithms in Higher Education: Post-Covid Trends, Challenges, and Ethical Implications
(Mount Kenya University, 2025-12-05) Mogoi,Oganda Bartholomew, Kamau,John,Ongus,Raymond
The rapid transition to online learning during and after the COVID-19
(Corona Virus Disease) pandemic has heightened the need for secure,
scalable, and ethical online exam systems. AI-powered mobile proctoring
frameworks have emerged as viable alternatives to traditional invigilation
methods, enabling automated anomaly detection and behavior analysis
through machine learning algorithms. This systematic review examines post COVID trends, technological developments, challenges, and ethical
implications of mobile AI proctoring in higher education. Following
PRISMA 2020 guidelines, 180 studies were retrieved and screened, with 20
peer-reviewed articles meeting the inclusion criteria. Findings reveal that
while AI-powered proctoring enhances scalability, integrity, and real-time
monitoring, it raises significant concerns about privacy, algorithmic bias,
accessibility, and technical reliability. The review identifies gaps in relation
to technical and methodological issues, ethical and social concerns, and
institutional and infrastructural readiness. This review illustrates a lapse in
the existing literature, which focus on resource intensive proctoring
frameworks without considering mobile compatibility and light-weight
frameworks, discusses technical challenges, and recommends future
research directions to balance technological effectiveness with ethical
standards.
Synthesis and characterization of silver Nanoparticle elecrocatalyst embedded onto indium tin oxide electrodes for degradation of azo dyes
(Mount Kenya University, 2025-11-05) Osemba,Martin Ouma; Muriuki,Mary; Karenga,Samuel
The research was conducted to establish the effectiveness of silver nanoparticles embedded on indium tin oxide (ITO) thin film conducting material in causing the textile azo dyes effluent degradation. The Overall Objective was to synthesize and characterize silver nanoparticles electrocatalyst embedded on indium tin oxide for the degradation of azo dye in the textile effluent. The 40.0 g of powdered crab shells resulted in 23.0g of chitin after demineralization and 7.2 g (31.3 %) of chitosan. Chitosan obtained from crab shells exhibited 89.5% degree of deacetylation showing efficiency in reduction and stabilization of silver nanoparticles from the Ag+ ions. The UV-Vis spectroscopy showed the formation of spectra with λmax at 420 nm. The scanning electron microscope (SEM) depicted nanoparticles showing spherical morphology with size range of 50 nm. FTIR signals were recorded at 1658 cm−1 corresponding to the amide (C=O) bonds, at 1089 cm−1 representing secondary alcohol (C-O-C) bonds at 564 cm−1 plane with bends NH, plane-out and bends C−O. C-H stretching vibrational signal was noted at 2927 cm−1, a broader band at 3426 cm−1 for an overlap between the O−H stretching vibration and the N−H stretching vibration of the oligosaccharide applied in the capping. The intensity of the O−H and N−H stretching bands emanated from the hydroxyl and amino groups thus shifting to 3426 cm−1, implying that chelation of silver with both O−H and N−H groups of chitosan actually took place. The percentages of azo dyes degradation were as follow: 68.4%, 72.5% and 93.1% using electrocoagulation, ITO and ITO-AgNPs coupled electrodes respectively. The results obtained from the two factors ANOVA with replication indicated significant difference (p= 0.0024) when the silver nanoparticles embedded on indium tin oxide electrodes were utilized in the degradation of these azo dyes in the effluent samples. In all the four samples it was noted that, 8 ppm of the silver nanoparticle concentration applied to the ITO thin film electrodes resulted in the least power consumption maximum of 0.4536 watts with average values of 0.0300±0.0023 hours and a current flow of 0.63 A. The average specific consumption of energy at 12 V was 2.110 kWh/m3 compared to 1.318 kWh/m3 at Pd of 24 V respectively. IR drop was minimized by lowering the created gap within the thin film electrodes to 0.2 cm and raising the surface area of the cross section of electrodes and specific solution conductance. The COD listing for the samples after treatment fell below 100 mg/L which is much lower than the acceptable limits of COD ≤250 mg/L. The BOD for dye effluent from the two-way ANOVA with replication portrayed a significant variation (p=0.0000238) when compared to the one of WHO 2002 with the range of 150±5 mg/L. The colour removal was 99.97% showing that, the optimized process was effective and efficient in the degradation of these azo dyes in
Production of Chitosan from Crab Shells
(Mount Kenya University, 2024-09-07) Osemba,Martin Ouma; Muriuki,Mary; Karenga,Samuel
The amino polysaccharide of chitin polymer happens to be the most
commonly known polymer. Chitosan as a derivative of chitin is
obtained through demineralization and deacetylation. Owing to the
special properties of chitin and chitosan for instance their bio compatibility, bio-biodegradability, non-toxicity and also capability
to form films, have resulted in their suitability in chemical and thermal
conductivity applications. In the field of nanotechnology, chitosan based materials are currently being widely applied. The purpose of
this review is to synthesize and characterize chitosan obtained from
the crab shells. The absorption band obtained from FTIR between
1220 cm−1 and 1020 cm−1 represented free amino group (−NH2).
The 40.000 grams of powdered crab shells resulted in the formation
of 23.000g of chitin after undergoing the process of demineralization
to eliminate the minerals available in the crab shells. The removed
minerals from the crab shells constituted 17.000 g (39.53%) of the
total dry weight in the crab shell. The water binding capacity (WBC)
was found to be 69 %.
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