Browsing by Author "Mwithiga, Gikuru"

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    Evaluating the surface functional groups on banana leaf petioles and the resultant biochar for potential adsorbance
    (JMES, 2020) Ndung’u, Paul W.; Mwithiga, Gikuru; Onyari, Charles N.; Muriithi, Genson; Mukono, Simon T.
    The presence of surface functional groups is key to the performance of an adsorbent material. The aim of this study was to evaluate the presence of functional groups on banana leaf petiole and on biochar made from banana leaf petiole. These functional groups assist in determining the potential of the material as an adsorbent for pollutants and heavy metals in waste water. Banana leaf petioles were collected from a single plantation and analyzed using the Fourier transform infrared spectroscopy. The material was then pyrolyzed at pyrolytic temperatures of 300°C, 400°C and 500°C, and the resulting biochars were analyzed to identify the surface functional group. The results showed the presence of hydroxyl and carboxyl functional groups on the banana leaf petiole before pyrolysis. The biochars also showed presence of hydroxyl and carboxyl functional groups whose presence and abundance reduced with increase in pyrolytic temperature. The presence of hydroxyl and carboxyl functional groups in a material has been related to its ability to adsorb metals in waste water and thus the banana leaf petiole as well as its resulting biochar would be a promising adsorbent for waste water remediation
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    Rosemary (Rosmarinus officinalis L.) growth rate, oil yield and oil quality under differing soil amendments
    (Heliyon, 2022) Mwithiga, Gikuru; Maina, Samuel; Gitari, Josiah N.; Muturi, Phyllis
    In this work, we examined the influence of different soil amendments namely cow manure alone (Cm), cow manure plus fertilizer (Cm þ F), fertilizer alone (F) and unamended check, control on rosemary growth rate, fat content, oil yield and oil quality. Plant height (PLH), number of primary branches per plant (NOPB) and survival rate were assessed at 0, 90, 180, 270 and 360 days after planting during the 2020–2021 growing season. Rosemary plant essential oil and fat content were extracted using steam distillation and Soxhlet methods, respectively, and determined for quality using the gas chromatography with mass spectrometry (GC-MS) method. Plants grown under Cm had a higher PLH and NOPB, whereas the F treatment largely affected the survival rate of rosemary plants than the control. A total of 26 constituents were identified from the obtained rosemary oil grown under different treatments by use of GC-MS analysis with Cm treatment containing the highest number of oil compounds. The main rosemary oil compounds in the present work were alpha-pinene (29.80%–34.34%), eucalyptol (27.15%–30.26%), verbenone (7.63%–8.14%) and geraniol (4.47%–5.22%). The oil yield from the steam distillation method ranged from 0.45% (v/w) to 0.59% (v/w) while the fat content as measured using the Soxhlet method ranged between 11.22% and 13.36% across various treatments. The essential oil yield and fat content from rosemary grown under Cm, Cm þ F, or F conditions were not significantly different. This study shows that Cm markedly influenced rosemary oil quality when compared to other soil amendments.