Dissertations.

Permanent URI for this collectionhttp://localhost:4000/handle/20.500.12504/99

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Catalytic potential of natural zeolites and selected metalic ores in pyrolysis of groundnut shells for bio-oil production
(Kyambogo University (un published work), 2019-07) Kalega, Ivan Fredrick
Catalytic pyrolysis is a promising thermochemical method of conversion of biomass to chemicals and fuels compatible with current petrochemical engines. Catalytic modification of pyrolyzed bio-oils are geared towards the elimination and substitution of oxygen and oxygen containing functionalities in addition to increasing hydrogen to carbon ratio in the final product. Recent progress has focused on both hydrodeoxygenation and hydrogenation of bio-oil using a variety of metal catalyst in the production of aromatic compounds from bio-oil using catalytic pyrolysis. However, current effectiveness of catalysts and conversion efficiency remain a challenge. In this study five naturally occurring inorganic materials from Usuuku rock, Kilembe mines rock, Tiira soil, Katwe salt and Manafwa river zeolites, having traces of transition metal elements were investigated for their influence on H/C and O/C ratio of bio-oil produced by pyrolysis of groundnut shells. The results showed bio-oil catalysed by zeolitic with metallic ore in the framework had a high H/C ratio and generated are hydrocarbons, that is, paraffins, olefins and aromatics than those without catalyst. Basing on the results of the study, it was concluded that different catalysts have impact on product composition, with catalysts of highest SiO2/Al2O3 producing more light gases. This result agrees with Cheng et al. (2000) who studied furan conversion to aromatics and olefins using HZSM-5. It was also concluded that the natural catalytic materials enhanced yields of the petroleum like compounds mentioned above, i.e., Kilembe ore for benzofuran; Katwe salt for aromatics; and Manafwa catalyst for olefins, CO and aromatics. This was based on eraspec fuel analyser and showed that the materials selected had catalytic potential for pyrolysis of groundnut
Microbial and heavy metal contamination in herbal medicines in Uganda
(Kyambogo University, 2019-10) Musoke, Willy
The use of herbal medicines in various countries has been on the increase over the years for primary health care since they are cheap and easily accessible. However, herbal medicines present safety concerns which are continuously undermined by practitioners who use unhygienic methods of preparation. This subjects them to relatively high risks of contamination by pathogenic microbes, organic and inorganic pollutants, mycotoxins, endotoxins, and agrochemical residues. This research focused on heavy metal and microbial contamination in different herbal medicines sold in Kampala Capital City markets. Five different herbal medicines used for treatment of ulcers, cough, malaria, and diabetes were randomly selected from different markets in Katwe, Nateete and Mengo markets within Kampala Capital City Authority. All the herbal medicines were analysed for microbial contamination and only 14 herbal medicines were tested for heavy metal toxicity. Bacterial isolates were identified basing on morphological, cultural and biochemical tests. Heavy metals were quantitatively determined using atomic absorption spectrophotometry. The study focused on contamination with most prevalent micro-organisms found in unhygienic and polluted environments of Escherichia coli, Enterobacter aerogenes, Staphylococcus aureus and heavy metals of Nickel, Chromium, lead, and cadmium and their concentrations in ready to use herbal medicines of cough, malaria, ulcer and diabetes. Approximately 90% of the herbal medicines analysed were found contaminated with pathogenic bacteria, of which Staphylococcus aureus, Escherichia coli, were the most prevalent micro-organisms. Herbal medicines used for the treatment of ulcer and cough were found having the highest contamination by microbes of about 65%, diabetes and malaria with 25% contamination. Heavy metal contamination was about 85% of which lead and Nickel were abundant in most herbal medicines analysed in the ranges of 0.0120 to 2.0808for lead and 0.0120 to 0.9548 for Nickel. Cadmium and Chromium were not detected. About 40% of the ulcer and malaria herbal medicines analysed showed high Nickel concentration to about 60%, while lead contamination predominated to about 75% in most therapies. The concentrations of lead and Nickel were higher than the maximum permissible daily limits in 60% of all herbal medicines analysed. Tests for specific micro-organisms were carried out and samples showed contamination by Escherichia Coli, Staphylococcus, aureus, fungus and moulds but none of the samples were contaminated by Salmonella species. Contamination with toxic heavy metals may be as a result of polluted environment, soils and methods used for preparation.
Optimization of the physicochemical parameters of selected agricultural wastes to increase biosynthetic gas and biochar yields
(Kyambogo University (unpublished work), 2019-10) Opedun, John Chrysostom
Biosynthetic gas and biochar are gaseous and solid fuels, respectively, that can be produced from various lignocellulosic feedstock via pyrolysis and are recognized as clean and attractive sources of renewable energy. They can be easily transported and used directly in boilers and modified turbines or upgraded for chemical production. In this work, physicochemical characterization; moisture, ash, volatile matter, total solids, hemicellulose, lignin and cellulose contents were gravimetrically determined and subsequent pyrolysis of agricultural wastes namely; groundnut shells, coffee and rice husks to produce biosynthetic gas and biochar were conducted. The parameters; moisture, particle size and cellulose, that were used to improve the biosynthetic gas and biochar yields were optimized using Design-Expert® software Stat-Ease version 7.0.0 USA. Response Surface Methodology and Box-Behnken design were applied. Results showed that rice husks had the highest amount of ash and total solids content at averages of 22.94 ± 0.75% w/w and 89.54 ± 0.18% w/w, respectively. Coffee husks had the least amount of ash with an average of 1.58% w/w, and total solids at 87.69 ± 0.51% w/w but with the highest amount of cellulose; 40.45 ± 1.58 % w/w, followed by groundnut shells at an average of 28.28 ± 4.45% w/w, and finally rice husk had the least amount of cellulose in the magnitude of 20.81 ± 3.61% w/w. Moisture content was essentially similar across all the biomass samples analyzed at averages of 10.46 ± 0.18% w/w, 12.31 ± 0.51% w/w and 12.49 ± 0.70% w/w for rice and coffee husks, and groundnut shells, respectively. Basing on the overall interactive effect of particle size, moisture and cellulose content to maximize yields of biochar and biosynthetic gas, the most optimal interaction that yielded the highest quantity of biochar (1.54 g) was found to be at levels of 0.36 mm, 10.3% and 25.45% for particle size, moisture and cellulose content, respectively, whereas the most optimal interaction that yielded the highest quantity of biosynthetic gas (40.10 cm3) was found to be at 2.86 mm, 0% and 32.52% for particle size, moisture and cellulose content, respectively. In both interactions, cellulose levels corresponded to groundnut shells as the best biomass material for producing biochar and biosynthetic gas. The study recommends the use of groundnut shells for pyrolysis to produce high yields of both biochar and biosynthetic gas.
Determination of selected acaricide residues in soils and water resources around cattle dip tanks in Mbarara district, western Uganda
(Kyambogo University (un published work), 2019-10) Ssenoga, Eric
This study determined the levels of selected acaricide residues in soils and water samples around cattle dips in Mbarara District western Uganda. Samples were collected, prepared and analysed for amitraz, chlorpyrifos and cypermethrin residues by gas chromatography equipped with a Flame Ionization Detector (GC/FID). The obtained data revealed evidence of amitraz, chlorpyrifos and cypermetherine contributing to the presence of acaricide residues in the area. The observed quantities were higher than United States permissible maximum residue limits (MRL) for agricultural soils. The amitraz, chlorpyrifos and cypermethrin residue concentrations at the sampled sites are high near the dip and reduce with all investigated distance of 25 m, 50 m and 75 m away from the cattle dip tank. This could be as a result of the cattle carrying some acaricide as they move away from the cattle dip tank and not all the acaricides flow back into the cattle dip tank. The data obtained from obtained from analysis of samples indicated presence of amitraz, chlorpyrifos and cypermetherin present in the area for all the studied farms. There was a significant difference in amitraz residue concentration in water samples from farms A compared to farms B and C this is due to different dosing in farm A compared to B and C. However, farms D and E were at zero because amitraz was not used as acaricide in these particular farms At farms D and E, only chlorpyrifos and cypermethrin residues were detected and no amitraz residues was detected at any of the studied distances away from the cattle dip tanks. The data obtained from water resources showed that only amitraz residues were detected from water samples collected from farms A, B, and C at all studied distances away from the cattle dip tanks with no Chlorpyrifos and cypermethrin being detected at the three farms A, B and C xii At farms D and E, only Chlorpyrifos and Cypermethrin residues were reported from water samples collected at farms E and D and no amitraz residues was detected at any of the studied distances away from the cattle dip tanks. The study from cattle dip samples showed that amitraz was found in the three dip tanks from farms A, B, and C while Chlorpyrifos and cypermethrine were detected from farms D and E. Farm A had the highest amitraz concentration, followed by farm B and then farm C. All the concentrations exceeded the allowable maximum standard values / Normal range of 250 ± 5 ppm of amitraz inside the cattle dip tank an indication of overdosing of the cattle dip tanks by farmers. At farms D and E, both Chlorpyrifos and cypermethrin were reported with farm E having the highest concentration of Chlorpyrifos and cypermethrine followed by farm D with concentration of Chlorpyrifos and cypermethrine. All the concentrations exceeded the allowable maximum standard values / Normal range of 500 ± 5 ppm Chlorpyrifos and 50 ± 5 ppm for cypermethrin inside the cattle dip tank an indication of overdosing of the cattle dip tanks.
Fatty acids, heavy metal concentration, and characteristics of selected oil seeds grown in west Nile, Uganda
(Kyambogo University, 2021-03) Wathum, Jimmy
In this study vegetable oils extracted from three types of oil seeds namely; sunflower (helianthus annus), sesame (sesamum indicum) and peanut (Arachis Hypogaea) grown in west nile sub-region were investigated. Fatty acid composition, heavy metal content, cadmium (Cd), zinc (Zn), iron (Fe), lead (Pb) and characteristics of the oils were determined using GC/MS, AAS and AOAC standard methods respectively. Results for fatty acids showed that oleic, linoleic, palmitic, stearic, behenic, lignoceric, and linolenic acids were present in all the oils.The contents of the major fatty acids ranged from (44.06 to 44.12%) oleic, (30.29 to 31.51%) of linoleic, and (10.93 to 13.07%) palmitic acids. This result demonstrates that sesame, sunflower, and peanut oils are of unsaturated type, but belonging to mid-oleic acid subclass. The polyunsaturated to saturated fatty acid ratios of the oils were >1, the minimum recommended by FAO. Results of heavy metal determination revealed that iron and lead were detected in all the oil samples and the concentration ranged from 2.330-14.982mg/kg for iron and 1.944-2.126mg/kg for lead (Pb). The highest concentration of lead ((Pb) and iron (Fe) were in sunflower and sesame oils respectively. Cadmium and zinc were not detected in all the oils.The levels of Lead and Iron were above the maximum permissible limit of (0.1mg/kg) for Lead, and (1.5mg/kg) for Iron, respectively. Heavy Metals like iron (Fe) in vegetable oils enhance the oxidation of fatty acids to esters, which affect the nutritional value and properties of oil. Lead (Pb) is toxic to the body even at a low concentration. Results of the oil quality characteristics showed that the oils exhibited satisfactory results regarding density, viscosity, iodine value, peroxide value, acid value and saponification value. The peroxide value was found in acceptable range of 1.42 to 9.25 meq/kg. While iodine value varied from 79.64 to 126.59gI2/100g. Keywords: Fatty Acids, Heavy Metal, Vegetable Oils, Oil characteristics
Electrodeposition of nickel-metalloid alloy films and their investigation for electrocatalytic water splitting
(Kyambogo University, 2021-03) Ssemwanga, Herbert
Electrocatalytic splitting of the water molecule to produce hydrogen as an energy carrier provides a very promising pathway for provision of green and inexhaustible renewable energy for the future. The bottleneck of this reaction is the sluggish kinetics of the OER that makes the processes to be extremely energy intensive. Electrochemists have devoted much research efforts in finding cost-effective electrocatalysts that can speed up the OER during electrochemical water splitting. In this study, reference (NiB, NiP and NiTe) metalloid alloy powders pre-synthesized at Ruhr University, Germany and (Ni-Ga and Ni-In) metalloid films synthesized by electrodeposition were investigated for the OER activity in an alkaline electrolyte using LSV. The results showed that the optimal number of CV deposition cycles for the highest OER activity were 7 for Ni, 7 for Ga,3 for In,7 for Ni-In and 5 for Ni-Ga composite electrocatalytic films. The OER activity of 𝑁𝑖(𝑂𝐻)2formed by electrodeposition was several fold higher than that of the pure Ga and In films, as well as of the composite Ni-Ga and Ni-In films. It was concluded that CV deposition cycles that had the highest activity and therefore the highest performance were; 7 for Ni, 7 for Ga ,3 for In ,7 for Ni-In and 5 for Ni-Ga composite electrocatalytic films respectively. Ga and In species exist as discrete domains rather than alloys in the Ni-Ga and Ni-In composite films. The attempted method for synthesis of Ni-Ga and Ni-In alloy films by electrodeposition most likely led to the formation of Ni-Ga and Ni-In composite films with discrete domains of oxides of their respective elements but not alloys.
Phytochemical investigation of ipomoea cairica for antimicrobial agents
(Kyambogo University [unpublished work], 2023-04) Opio, Boniface
The emergence of new infectious diseases and the resurgence of several infections has put the people in Saharan and sub-Saharan Africa to an assiduous risk. This has created the necessity for studies directed towards the development of new alternatives for antimicrobial agents. In this study a portion of the dichloromethane/methanol (1:1, v/v) crude extract from the air dried and pulverized aerial parts of Ipomoea cairica was subjected to preliminary phytochemical screening which revealed the presence of alkaloids, sterols, flavonoids, tannins, saponins, terpenoids and phenols. Another portion of the crude extract was subjected to repeated column chromatography over silica gel leading to the identification of two compounds; Diisobutyl phthalate (53) and Friedelin (54) which were characterized and elucidated using various spectroscopic and spectrometric techniques. The crude extract and the isolated compounds were evaluated for antimicrobial activities against four bacterial strains; Escherichia coli, Salmonella typhi, Pseudomonas and Staphylococcuss aureus, and three fungal strains; Aspergillus niger, Penicillum chrysogenum and Candida albicans using well agar diffusion assay and their minimal inhibitory concentration (MIC) values determined using a 2-fold dilution technique. The crude extract exhibited good antimicrobial activities with zones of inhibitions; 20± 0.25, 26 ± 0.10, 24 ± 0.12 and 14 ± 0.05 mm for E. coli, S. typhi, P. aeruginosa and S. aureus, respectively, and the zones of inhibitions for fungal strains were as follows; 16± 0.5, 24± 0.00 and 20± 0.41 mm for A. niger, P. chrysogenum and C. albicans, respectively. The two isolated pure compounds were only tested against the four strains of bacteria and exhibited relatively weak activities: Compound (53); 8.0 ± 0.22, 4.0 ± 0.32, 6.0 ± 0.00 and 6.0 ± 0.55 mm, and Compound (54); 8.0± 0.05, 5.0± 0.50, 8.0± 0.12, 10± 0.50 mm for E. coli, S. typhi, P. aeruginosa and S. aureus, respectively. The two isolated pure compounds showed minimum inhibitory concentration (MIC) ranging from 125 to 1000 𝜇g/ml respectively.
Phytochemical investigation of Alstonia Boonei for Antimicrobial activities
(Kyambogo University [unpublished work], 2023-07) Busulwa, George
Alstonia boonei was investigated with the aim of identifying bioactive compounds present in its leaves. The plant was chosen because it is one of the most widely used plants in traditional herbalimedicine. The leaves of Alstonia boonei were collected from Nakawuka village, Wakiso District, Central Uganda, in November 2017. Extraction of the crude was done by soaking the dry powdered leaves in a mixture of dichloromethane and methanol (1:1, iv/v) followed by preliminary phytochemical screening. Isolation and purification of compounds was carried out using Column Chromatography over silica gel and the extent of separation was monitored using Thin Layer Chromatography(TLC). Bioactivity of ithe crude extract, as well as one isolated compound, was determined against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Salmonella typhi Preliminary phytochemical analysis revealed the presence of tannins, flavonoids, saponins, terpenoids, cardiac glycosides and alkaloids. The isolated compounds were identified with the help of a combination of both 1D and 2D NMR spectroscopic techniques. Two compounds were isolated and identified; viz: an amide derivative, trans fagaramide (1) and a triterpene, lupeol i(2). Compound 1 is hereby reported for the first time from the genus Alstonia. The crude extract exhibited strong antibacterial activity against E. coli in the disc diffusion assay with a diameter zone of inhibition of 20 mm and moderately active against P. aeruginosa and S. aureus (diameter zone of inhibition of 10 and 9 mm, respectively), but it was inactive against S. typhi. Trans-fagaramide showed moderate antibacterial activities in the disc diffusion assay with zones of inhibition (diameter) of 13, 12, 10 and 10 imm against S. typhi, P. aeruginosa, S. aureus and E. coli, respectively. The minimum inhibitory concentration of trans-fagaramide was 125 mg/mL against P. Aeruginosa and 250 mg/mL against the rest of the test bacterial strains. The results in this study justify the use of Alstonia boonei in the management of infectious diseases by traditional healers.
Assessment of the quality of levonorgestrel emergency contraceptive tablets (morning-after pill) sold in Uganda
(Kyambogo University [unpublished work], 2023-08) Babirye, Lydia Brenda
Use of poor quality emergency contraceptives may lead to unwanted pregnancies. Many unwanted pregnancies lead to illegal abortions having a devastating impact on the health of the girl child and women at large. This study was aimed at assessing the quality of levonorgestrel tablets sold on the Ugandan market. The quality of levonorgestrel tablets was established through collection of samples from the Eastern, Western, Central and Northern regions of Uganda. The High Performance Thin Layer Chromatography (HPTLC) and the High Performance Liquid Chromatography (HPLC) analytical techniques were used to identify and determine the content of levonorgestrel, respectively. The quality parameters assessed included visual inspection, identification, content uniformity, assay and dissolution. Results showed that thirteen percent of samples found on the market were counterfeits and all belonged to brand G. The samples that had been confirmed counterfeits further failed the uniformity of content, assay and dissolution tests. Eighty-seven percent of the samples found on the market passed the assay and uniformity of content test and the statistical analysis conducted at 95% CI revealed significant differences (ANOVA, p < 0.05) within the brands in the mean uniformity of content and assay results. Further findings showed that 30% of the samples on market exhibited inadequate release of levonorgestrel by dissolution testing whereas 13% showed no release of levonorgestrel. Similarly, the statistical analysis conducted using the one-way ANOVA at 95% CI revealed that there was a significant difference (p < 0.05) in the drug release of the different brands of levonorgestrel tablets examined in the study. From the study it was observed that only 57% provided the stated level of contraceptive action, 30% provided questionable results whereas 13% offered no prevention against unwanted pregnancy. The statistically significant differences observed further indicated the availability of levonorgestrel tablets on the market that are not therapeutically equivalent. It was concluded that there is need to emphasize regular assessment of the quality of emergency contraceptives on the market in order to lower the risk of patients being exposed to products of poor quality, safety, and efficacy.
Physicochemical assessment of the quality of Albendazole tablets on the Ugandan market
(Kyambogo University [unpublished work], 2023-08) Mbonye, Alex Sabiiti
Albendazole tablets are listed by World Health Organization as essential medicines effective for treatment for parasitic worm infections and are indeed widely used in many public deworming campaigns in Uganda. “Albendazole tablets being a high-volume consumption product coupled with the fact that they cure illnesses often referred to as those of the poor make them have a very high risk of being counterfeited. Despite this highly associated risk, there is no comprehensive assessment and documentation available on the quality of Albendazole tablets on the Ugandan market. In this study, both qualitative and quantitative assessments were performed to evaluate the quality of different brands of Albendazole tablets sold in wholesale pharmacies in Kampala, Uganda. A visual inspection checklist was used for the assessment of the physical attributes and packaging requirements. Ultraviolet-visible spectroscopy (UVS) and High-Performance Liquid Chromatography (HPLC) were used for confirmation of the presence and amount of the Active Pharmaceutical Ingredient (API).” A total of 40 batches of Albendazole tablets from 10 different brands were collected and evaluated. All brands of Albendazole tablets, except one, had acceptable physical characteristics. All the 10 brands (40 batches) passed the assay test, with average assay values ranging from 95.9 % (383.6 mg/mg) (to 99.5 % (398 mg/mg). Eight (20 %) batches failed the disintegration test. Three brands (30 %) of 10 brands failed the dissolution test with percentage dissolution values ranging from 0.0 % (0 mg/mg to 79 % (316 mg/mg). The most significant revelation of this study was the batches of Albendazole chewable tablets that did not completely dissolve as demonstrated by dissolution values ranging from 0% to 1%. In conclusion, the Ugandan market had Albendazole tablets of both good and bad quality in circulation. This calls for regulatory enforcement to ensure that all these products that did not meet the specifications are recalled from the market and the manufacturers cautioned.

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