Dr. Fredrick Mzee Mwazighe

The boron-doped diamond electrode has been widely applied in electrochemical process for wastewater treatment based on the generation of hydroxyl radicals (•OH). This study investigated the formation efficiency of 2-HTA through the interaction between •OH radical and terephthalic acid (TA) to monitor the •OH formation. Results show that the 2-HTA formation efficiency did not depend on the initial concentration of scavenger (here, TA) in the investigated range of 0.1 to 1 mM TA. Meanwhile, other factors, such as current density, supporting electrolyte, sodium hydroxide have a significant influence. The optimal condition was established: concentration of electrolyte (0.05 M Na2SO4); initial concentration of TA (0.1 mM); concentration of NaOH (1 mM); current density (j = 20 mA cm–2). The selectivity of TA was evaluated by Faradaic efficiency (η) and hydroxylation yield (γTAOH), indicating that Faradaic efficiency (η) for 2-HTA formation was in the range of 10–5–10–7, while the hydroxylation yield of •OH (γTAOH) into 2-HTA was 0.03–0.12.

The electrochemical oxidation of anthracene on a bare glassy carbon electrode results in electrode fouling and reduced sensitivity in its detection. Multi-walled carbon nanotubes were used to modify a glassy carbon electrode for the electrochemical detection of anthracene because of their antifouling and peak enhancement properties. The peak current for anthracene oxidation was enhanced by 73.64%, and the peak potential shifted by 53 mV to a slightly less positive value. The electrochemical process was determined to be mixed diffusion- and adsorption-controlled, and a preconcentration or accumulation time was necessary in the analysis of anthracene. Square wave voltammetry was used to analyze increasing concentrations of anthracene; a dynamic linear range of 50–146 μM (R2 = 0.98452) and a limit of detection of 42 μM were established. The sensor platform was used to detect anthracene in a spiked sample of tap water, albeit at lower than expected concentrations because of its low solubility in water.

Recent statistics show a rise in the margin of consumption and utilization of essential oils. People
have turned their attention to traditional medicines, and so the demand for essential oils in the
international market has increased drastically. However, essential oil extraction processes have
been observed to suffer from minimum output levels. The purpose of this study was to
investigate the effects of changing the process parameters (time of extraction, leaf sizes and
leaves to water ratio) and their contribution to maximizing the process of extraction and also the
composition of Eucalyptus grandis oil to establish utility of the oil.The extracted oil’s refractive
index was determined and GC-MS analysis of the oil was also done to determine the
composition of the oil. There was an increase of %yield with increase in time up to 150
minutes.Quality of the oil extract was desirable from appearance and smell. Variation in oil yield
was also noted from varying the leaves to water ratio, with 1:12.5 (w/v) being optimal. The
adjustment of leaf sizes was found to be most effective with a very high increase in yield margin.
The whole leaves produced the highest amounts of oil. More than 20 compounds were identified
with many of them appearing in eucalyptus oil from other species seen in literature.
Key Words: Essential Oils, Eucalyptus grandis, Clevenger Distillation, Optimization, GC-MS

Microalgae has had a number of applications. This study explores the formation of biodiesel from lipids and
formation of charred biomass fuel from the algae species found at Ruai Wastewater facility at Ruai, Nairobi. The
resulting biomass after solvent extraction was carbonized and the gross calorific value determined using a constant
volume bomb calorimeter. The bio-oil obtained from the algae was transesterified and the calorific value
determined. In one of the cases, carbon dioxide was bubbled through fresh algae from the waste water facility and
the biodiesel from this sample which was later sun-dried, crushed, then subjected to solvent extraction and
subsequent transesterification had the highest calorific value of 27,620 KJ/g compared to 22,758KJ/g in algae
sample which was not subjected to such a treatment. In the case of the charred biomass fuel, the gross calorific
value was found to be approx 23,132 KJ/g which makes it a medium calorific value fuel. GC-MS analysis was
performed on one of the transesterification samples and methyl esters of the isolated fatty acids were identified as
methyl esters of polyunsaturated fatty acid α-linolenic acid (18:3, n-3; ALA), Hexadecanoic acid and cis-9-hexadecenoic acid. In addition an alkane heptadecane was also isolated. This study shows that algae, which is
present in many water systems in Kenya can be used as a valuable source of fatty acids that are taken in diet by
animals and humans thus building a healthy nation.
Keywords: Microalgae, transesterification, biodiesel

Blue colored essential oil samples were obtained from chamomile flowers
by a Solvent Extraction Clevenger Distillation (SECD) method and by the
standard Clevenger distillation of Chamomile flowers. The solvents used
were hexane, acetone, dichloromethane (DCM), ethyl acetate and
methanol. The solvents were evaluated in terms of the yield of extract, and
the quality of extract (determined by Gas Chromatography-Mass
Spectrometry). Of all the SECD extracts, the DCM extract gave the highest
yield of the essential oil while the hexane extract gave the lowest yield of
the blue essential oil.