Chemistry Department
http://repository.dkut.ac.ke:8080/xmlui/handle/123456789/441
2024-03-29T12:17:46ZSectoral Value Chain Mapping in Kakamega County, Kenya
http://repository.dkut.ac.ke:8080/xmlui/handle/123456789/8465
Sectoral Value Chain Mapping in Kakamega County, Kenya
Murimi, Martin; Cheloti, Michael; Wekesa, Ingrid; Onyuka, Arthur
The Kenyan agricultural sector will play a pivot role in achieving its national development roadmap,
Vision 2030. This report explores the agricultural value chains within Kakamega County, Kenya, focusing
on sweet potatoes, bananas, soya beans, vegetables, palm oil, honey, and avocados. Data collection for
the study primarily involved direct engagement with stakeholders across the various sub-counties. The
study revealed the unique characteristics and challenges faced in each value chain, laying the foundation
for understanding the local agricultural dynamics. These challenges included equipment shortage, lack of
technical skills, and poor marketing strategies. Recommendations are put forward to address the specific
hurdles and optimize opportunities within each value chain. Fostering cooperative formations, exploring
value addition and enhancement of technical skills are the common themes across the recommendations
for the value chains. Further, training, certification acquisition, research and development and process
optimization have been suggested to bolster productivity, quality and market competitiveness. The
proposed interventions. The
proposed interventions require collaborative effort from the stakeholders including government agencies,
non-governmental organizations and the local communities. By creating an enabling environment and
implementing the recommended strategies, sustainable agricultural-based growth and economic
development, aligning with the national Vision 2030, can be fostered in Kakamega
2024-02-01T00:00:00ZKinetic and Isotherm Modelling of adsorption of Cr 3+ metal ions from Tannery wastewater on to unmodified and acid-modified Arabica coffee husks biosorbents
http://repository.dkut.ac.ke:8080/xmlui/handle/123456789/8464
Kinetic and Isotherm Modelling of adsorption of Cr 3+ metal ions from Tannery wastewater on to unmodified and acid-modified Arabica coffee husks biosorbents
Oloo, Charles Owino; Onyancha, Douglas; Muthakia, Gerald Kanyago; Nthiga, Esther Wanja
The kinetics and isotherm modeling of adsorption of Cr3+ ions onto unmodified coffee husk (UCH) and acid
modified coffee husk (MCH) biosorbent were successfully studied in batch experiments. Equilibrium data were
analyzed by Langmuir and Freundlich isotherm models. Equilibrium data best fitted to Langmuir isotherm. The
Langmuir adsorption capacity was higher in MCH (6.64 mg/g) compared to the UCH (3.85 mg/g). The
adsorption constant, b, was less than one in the two adsorption processes suggesting a high affinity of both the
UCH and MCH adsorbent for Cr3+ ions. The experimental data were fitted well with pseudo second order
kinetics with best fitness for both the UCH and MCH with regression coefficient (R2
) of 0.9792 and 0.9956,
respectively. The findings revealed that the unmodified and modified coffee husks have potential in removal of
Cr3+ from tannery wastewater
2024-02-01T00:00:00ZEvaluation of the Physical Properties of Goatskins Tanned using Banana (Musa spp.) Leaf Midrib Tannins
http://repository.dkut.ac.ke:8080/xmlui/handle/123456789/8343
Evaluation of the Physical Properties of Goatskins Tanned using Banana (Musa spp.) Leaf Midrib Tannins
Wangui, James K.; Ongarora, Benson; Onyancha, Douglas
Vegetable tannins have been studied over the years with an aim to reduce the pollution load caused by chrome tanning. Although mimosa tannins have been utilized commercially, they are expensive and not readily available. The purpose of this study was to assess the physical properties of leather tanned with banana leaf midribs tannins in order to determine their suitability as vegetable tannins. Selected banana leaf midrib samples were collected from Gikondi village in Mukurweini, Nyeri County, Kenya. They were shade-dried and ground into powder. The skins were processed conventionally using banana leaf midribs tannins of Musa sapientum Linn. and ‘Muraru’ (AA genome), with mimosa as a control. The physical properties of the resultant leathers were determined following the standard IUP methods. It was found that Musa sapenitum Linn, ‘Muraru’ (AA genome) and mimosa-tanned leathers had average shrinkage temperatures of 80.33 ± 0.74°C, 78.67 ± 0.47°C and 81.67 ± 0.94°C, respectively. The properties of the tanned leathers were compared with those of the control-tanned leather. Assessment of the physical properties indicated that the leathers met the minimum recommended values safe for Musa sapentium Linn-tanned leather, which failed at 30,000 flexes. These results indicate that banana leaf midribs can be used as an organic tanning agent source for production of leathers from goatskins
2024-01-01T00:00:00ZCharacterization of amorphous silicon nitride prepared from sand and coffee husk wastes by carbothermal reduction-nitridation
http://repository.dkut.ac.ke:8080/xmlui/handle/123456789/8329
Characterization of amorphous silicon nitride prepared from sand and coffee husk wastes by carbothermal reduction-nitridation
Ndung'u, Samuel N.; Nthiga, Esther Wanja; Wanjau, R.N.
The continued coffee demand in Kenya has amplified the
generation of its husk wastes causing disposal problems.
This has led to serious pollution to the environment.
Therefore, developing a greener and cost-effective ways
to handle these wastes is necessary. The current study
entailed the use of extracted silica and coffee husk biochar
as novel precursor materials for the synthesis of silicon
nitride (Si3
N4
) composite in an ammonia environment.
The silica was extracted from raw sand by alkali fusion
route. The biochar was prepared by pyrolytic treatment of
raw coffee husk biomass at 300 o
C for 5 hours followed
by acid leaching. The sand, extracted silica, raw and
biochar samples and silicon nitride composites were
characterized using X-Ray Fluorescence (XRF), Fourier
Transform Infrared (FT-IR), X-Ray Diffractometer
(XRD), Scanning Electron Microscope (SEM), Energy
Dispersive X-Ray (EDX) and Thermogravimetric
Analyzer (TGA). The results showed that the raw sand
contain quartz, calcite, microcline and clinochlore. The
results for the extracted silica showed a highly amorphous
silica containing hydroxyl (-OH) and siloxane (Si-O-Si)
functional groups. The alkali fusion process increased the
silica content to > 92 % from 83 % with oxide impurities
reduced to < 1 %. The characterization of biochar samples
showed a highly amorphous, porous carbon structure
with aromatic carbon bonds (C=C) and a negligible ash
content. The characterization of Si3
N4 powder showed
thermally stable, porous and highly amorphous material
with α-Si3
N4
and - Si3
N4
phases. The FT-IR results
showed Silicon-Nitrogen-Silicon (Si-N-Si), silanol (Si-
OH), Silicon-Nitrogen (Si-N) and Silicon-Silicon (Si-
Si) as important functional groups present in silicon
nitride composite material. The results revealed a greener
approach of Si3
N4 synthesis for application in vast
industrial fields.
2023-12-01T00:00:00Z