Thesis & Dessertations

AQUEOUS FLUORIDE BIOSORPTION USING CALCIUM-SPIKED AND NON- SPIKED Moringa oleifera SEED POWDER: INFLUENCE OF DOSAGE, PARTICLE SIZE, AND PROCESS PARAMETERS

2026-06-03T12:48:43Z

AQUEOUS FLUORIDE BIOSORPTION USING CALCIUM-SPIKED AND NON- SPIKED Moringa oleifera SEED POWDER: INFLUENCE OF DOSAGE, PARTICLE SIZE, AND PROCESS PARAMETERS CHAVAREGI, GEOFFREY Excessive fluoride concentrations in drinking water pose serious public health risks, including dental and skeletal fluorosis, particularly in rural, semi-arid and arid regions of developing countries where groundwater is the primary source of potable water. Traditional defluoridation methods remain costly, chemically intensive, or environmentally unsustainable, prompting the search for low-cost, eco-friendly alternatives. Moringa oleifera seed powder (MOSP) has emerged as a promising biosorbent, though its native adsorption capacity remains limited. This study aimed to enhance fluoride removal efficiency by modifying MOSP with calcium (Ca-MOSP) and to evaluate the influence of key process parameters including adsorbent dosage,particle size,pH,contact time, temperature and initial fluoride concentration; adsorption equilibrium behaviour, kinetic rates, and thermodynamic properties. Batch experiments were conducted under controlled laboratory conditions using both calcium-spiked and non-spiked MOSP to assess the effect of dosage, particle size, contact time, pH, temperature, and initial fluoride concentration. The biosorption performance was analysed using Langmuir and Freundlich isotherm models, pseudo-first-order and pseudo-second-order kinetics, and thermodynamic parameters such as enthalpy (ΔH°), entropy (ΔS°), and Gibbs free energy (ΔG°). Results showed that calcium spiking significantly improved fluoride removal efficiency, with Ca-MOSP achieving over 90% removal under optimal conditions (2 g/50 mL dosage, 40 mesh size, pH 7-, and 120- minute contact time), compared to 78% for the non-spiked powder. Finer particle sizes led to increased surface area and binding site availability, while increased dosage improved performance up to a saturation threshold. Adsorption was found to be pH- dependent, with neutral pH offering the best removal efficiencies for both biosorbent types. The adsorption isotherm data fitted best with the Langmuir model, suggesting monolayer adsorption on homogeneous surfaces. Ca-MOSP exhibited a higher maximum adsorption capacity (q e = 4.98 mg/g) and affinity constant (Kₗ = 0.442 L/mg) than the non-spiked variant. Kinetic data followed the pseudo-second-order model, indicating chemisorption as the dominant uptake mechanism, with high R² values (>0.99) and strong agreement between experimental and theoretical adsorption capacities. Thermodynamic analysis confirmed that biosorption was endothermic (ΔH° = +28.45 kJ/mol for Ca-MOSP), spontaneous (ΔG° < 0), and associated with an increase in system randomness (ΔS° = +85.6 J/mol·K). Thus, calcium-modified Moringa oleifera seed powder offers a significantly enhanced, sustainable, and low-cost alternative for fluoride remediation in drinking water. The findings support its potential for practical application in areas with fluoride endemism, particularly in rural and resource-limited settings. Recommendations include adopting Ca-MOSP in decentralised treatment systems and optimising operational conditions for field deployment. Future research should explore regeneration potential, competing ion effects, and long-term performance in continuous- flow and field-scale systems.

GREEN TECHNOLOGY FOR WASTEWATER MANAGEMENT: UTILIZING RICE HUSKS, COCONUT SHELLS AND CLAY AS ADSORBENTS FOR BASIC DYE RHODAMINE B AND SELECTED HEAVY METALS

2026-06-03T08:12:08Z

GREEN TECHNOLOGY FOR WASTEWATER MANAGEMENT: UTILIZING RICE HUSKS, COCONUT SHELLS AND CLAY AS ADSORBENTS FOR BASIC DYE RHODAMINE B AND SELECTED HEAVY METALS GICHUKI, JOHN Accumulation of heavy metals such as cobalt, copper, and lead and dyes such as rhodamine B (RB) released by various industries, poses a potential ecological risk of contamination due to their persistent nature and non-biodegradability. A remedial action is needed to mitigate this risk. A study was carried out to look into the possibility of eco-friendly and cost effective activated rice husk charcoal (ARC), coconut shell charcoal (ACC) and activated clay soil (ACS) in removal of heavy metals and rhodamine B dye from waste water. Three metal ions were selected, Cu2+, Co2+ and Pb2+ and were determined using atomic absorption spectrophotometer, AAS. The charcoal was obtained by burning rice husk and coconut shells which had been soaked in phosphoric acid in limited air. The ability of adsorbents to adsorb metal ions from water was investigated by carrying out batch experiment and varying parameters such as initial concentration, adsorbent dose, contact time, agitation speed, temperature and pH. Fourier Transform Infrared (FTIR) analysis detected presence of functional groups of Si-OH, Si-O, Si-O-Si, O-H and C=C in adsorbents upon activation which are responsible for adsorption. For the dye, a characteristic peak at 3200 cm-1 to 3070 cm-1 for aromatic stretch which was confirmed by a stretching vibration peak at around 1400 cm-1 was observed after adsorption. X-ray diffraction (XRD) data indicated that ACS was crystalline while ARC and ACC were amorphous. The X-ray fluorescence (XRF) results show that SiO2, Al2O3, and K2O were the main components where SiO2 were dominant especially in ARC and ACS. With Transmission emission spectroscopy (TEM) analysis, these nanostructures showed significantly different morphologies. Highly porous and hollow structures were visible in all cases though with differences. Brunauer, Emmett and Teller (BET) surface area and average pore diameter determination study showed that there was a relatively equal adsorption-desorption efficiency. This indicated that the adsorbents were highly reusable and that they had good stability. The efficiency of all the adsorbents towards the removal of heavy metals and dye increased with increase in temperature, time and surface area. Varying the pH showed that metals were adsorbed at a maximum pH of 6 while RB was highly adsorbed at pH 4. The equilibrium fitted the Langmuir equation well as compared to Freundrich. The R2 values for Langmuir ranged between 0.9928 to 0.9989 as compared to Freundlich which ranged between 0.9200 to 0.9671. The negative values of change in Gibb’s free energy (-1.55 to -0.581, -1.074 to -0.449 and -1.14 to -0.194 kJ mol-1 for ARC, ACC and ACS respectively) and positive values of change in enthalpy (32.034 to 37.562, 30.615 to 36.193 and 30.08 to 34.76 kJ mol-1 for ARC, ACC and ACS respectively) revealed the process to be spontaneous and endothermic. The use of a pseudo-second-order model, which indicates that chemical adsorption governed the process, allowed for a more accurate description of the adsorption process.

PHYTOCHEMICAL ANALYSIS AND ANTIBACTERIAL ACTIVITY OF Guizotia scabra LEAF, STEM BARK AND ROOT EXTRACTS FOR DENTAL CARIES CONTROL

2026-04-15T11:39:22Z

PHYTOCHEMICAL ANALYSIS AND ANTIBACTERIAL ACTIVITY OF Guizotia scabra LEAF, STEM BARK AND ROOT EXTRACTS FOR DENTAL CARIES CONTROL PAUL, ANJELINE JEPCHUMBA Medicinal plants offer promising alternatives for treating oral infections. This study investigated the phytochemical composition and antibacterial activity of Guizotia scabra tender leaf, stem bark, and root extracts against Streptococcus mutans and Streptococcus sobrinus, key pathogens in dental caries. Ethanol and acetone extracts were subjected to Standard laboratory tests for phytochemicals analysis, High- performance liquid chromatography (HPLC) for quantification of flavanoids, Fourier- transform infrared spectroscopy (FTIR) for determination of functional groups and antibacterial bioassays to assess antibacterial activity. Phytochemical tests revealed the presence of anthraquinones, alkaloids, terpenoids, flavonoids, steroids, saponins, and quinones. HPLC analysis confirmed the presence of myricetin and quercetin, with leaf extracts showing the highest concentrations (myricetin: 7.0013 ppm; quercetin: 0.901 ppm). Stem bark lacked myricetin but contained quercetin (2.4991 ppm), while root extracts had moderate levels of both (myricetin (2.0627 ppm) and quercetin (0.7027 ppm). FTIR spectra identified key functional groups, including O-H/N-H (3441 cm−1)1 linked to alkanoids (Quercetin ) (N-H /O-H group), C=O (1643 cm−1) which correlate to terpenoids, C-H/C-O (1396 cm−1) linked to alkaloids structure having N /O-H bond,2000 cm−1 to terpenoids /flavanoids and possible metal-ligand vibrations (538 cm−1). There is also a distinct C-N stretch (1250 cm−1) likely due to C-N stretching in alkaloids showed by leaf and root extracts. Antibacterial evaluation demonstrated that ethanol leaf extract had the highest inhibition against Streptococcus mutans (5.0 mm, 62.5%) and Streptococcus sobrinus (4.0 mm, 50%), followed by root extracts (3.0 mm, (37.5%) and 2.5 mm , (31.25%) respectively. Acetone extracts showed similar trends with the leaf extract at 4.6 mm, (57.5%) and 4.3 mm, (53.75%). However, commercial toothpastes showed superior inhibition (up to 7.0 mm, 87.5%) likely due to fluoride content and other additives. These findings suggest that Guizotia scabra possesses bioactive compounds with potential for natural oral healthcare applications. Further studies should optimize extraction; evaluate compound synergy, ensuring safety and efficacy for possible formulation of dental products.

PLASMID-MEDIATED ANTIBIOTIC RESISTANCE IN GRAM-NEGATIVE PATHOGENIC BACTERIA ISOLATED FROM RIVER SOSIANI AND WASTE WATER SYSTEMS IN UASIN GISHU COUNTY, KENYA

2026-04-15T11:17:02Z

PLASMID-MEDIATED ANTIBIOTIC RESISTANCE IN GRAM-NEGATIVE PATHOGENIC BACTERIA ISOLATED FROM RIVER SOSIANI AND WASTE WATER SYSTEMS IN UASIN GISHU COUNTY, KENYA AUMA, SHARON The widespread of bacteria resistance to antibiotics poses an immense threat to the public health. Aquatic ecosystems receive waste water which invariably contain different bacteria, chemicals and antibiotic residues that induces bacterial resistance to antibiotics, resulting into several treatments failures and deaths. Plasmid-mediated antibiotic resistance of bacteria through horizontal gene transfer has been reported to significantly cause resistance in susceptible bacteria. The current study identified antibiotic resistance genes present in gram-negative bacterial plasmids, isolated from River Sosiani and wastewater systems in Uasin Gishu County, Kenya. The sampling sites included Outspan-Nairobi bridge, Pioneer bridge, Moi Teaching and Referral Hospital, Eldoret prison, Kipkaren bridge, Huruma quarry influent, Huruma quarry effluent, Kipkenyo boundary influent and Kipkenyo boundary effluent. The study entailed bacteria isolation, identification, antibiotic susceptibility testing, plasmid DNA extraction and polymerase chain reaction of the antibiotic-resistant genes. Mean and standard deviations were analyzed using Microsoft Excel while Chi square was used to determine significant relationship existing between the phenotypic and genotypic resistance in bacteria. Most of the bacteria coliforms obtained were too numerous to count. A total of 10 gram-negative pathogenic bacteria species were detected, including Escherichia coli, Enterobacter aerogenes, Citrobacter freundii, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus vulgaris, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella enteriditis and Yersinia enterocolitica. All the 10 bacteria conferred resistance to penicillin, ampicillin, amoxicillin-clavulanic acid, ceftazidime, tetracycline, streptomycin and sulfamethoxazole-trimethoprim. Multi antibiotic resistance index was higher in E. aerogenes (0.83) but lower in Y. enterocolitica (0.58). Out of the nine antibiotic-resistant genes investigated, qepA and qnrA genes were present in the plasmids of all the 10 bacteria species, 70% of the total bacteria species had dfrA5, 70% had aadA1, 50% had blaKPC, 40% had mphA, 30% of the bacteria species had blaSHV and sul 1 genes (P≥1) while none of the bacterial plasmid DNA had AmpC gene. The study findings suggested that River Sosiani and the sampled wastewater systems contained different pathogenic bacteria and their plasmid-mediated antibiotic resistance genes which confer resistance to commonly used antibiotics. Therefore, effective waste disposal, continuous monitoring and proper pretreatments of water from River Sosiani and the sampled wastewater systems may reduce bacteria contamination and antibiotic resistance inducers, addressing challenges associated with antibiotic resistance in bacteria.

ANTIOXIDANT AND ANTIDIABETIC PROPERTIES OF Mondia whitei ROOT EXTRACT IN STREPTOZOTOCIN-INDUCED DIABETIC WISTAR RATS

2026-03-13T10:22:01Z

ANTIOXIDANT AND ANTIDIABETIC PROPERTIES OF Mondia whitei ROOT EXTRACT IN STREPTOZOTOCIN-INDUCED DIABETIC WISTAR RATS GITAU, KENNEDY KAMAU The rising global prevalence of diabetes mellitus (DM) and its complications presents a major health challenge and is exacerbated by the lack of a definitive cure and the side effects of existing treatments, thus, highlighting the need for safer and more sustainable anti-diabetic agents. This study investigated Mondia whitei root extract as an alternative therapeutic option for DM. While traditional medicine suggests that M. whitei possesses antioxidant and anti-diabetic properties, scientific validation is limited. This research aimed to address this gap. Qualitative phytochemicals analysis of crude root extract of M. whitei was done and it’s in vitro antioxidant properties evaluated through 2,2- diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and ferric reducing antioxidant power (FRAP) assays. DM was induced in twenty-four male Wistar rats by a single intraperitoneal injection of 65 mg/Kg body weight (bwt) of streptozotocin (STZ). Animals were randomly assigned to five groups each containing six subjects; Group I (normal control, saline), Group II (diabetic control, saline), Group III (diabetic rats 200 mg/Kg bwt extract treatment), Group IV (diabetic rats 400 mg/Kg bwt extract treatment), and Group V (diabetic rats 100 mg/Kg bwt metformin treatment). Treatments were orally administered for 21 days. Fasting body weights and blood sugar levels were measured weekly. After 21 days, animals were sacrificed and their blood and liver tissue samples collected followed by serum lipid profile, liver and kidney function indices analysis. Liver malondialdehyde (MDA) levels were measured, and liver and plasma’s ferric-reducing capacity were evaluated. Statistical analysis was performed using R software, with paired Student’s t-test and ANOVA determining statistical significance at 95% confidence level. The qualitative phytochemical analysis of the crude M. whitei root extract revealed the presence of saponins, phenols, tannins, alkaloids, flavonoids, glycosides, coumarins, steroids, and terpenoids, while anthraquinones were not detected. The extract significantly scavenged DPPH radical and reduced ferric ions in vitro. M. whitei also showed significant hypoglycemic, hypolipidemic and significantly reduced serum gamma-glutamyl transferase (GGT), alanine aminotransferase (ALT) and alkaline phosphatase (ALP). M. whitei treatment also significantly increased liver and blood plasma capacity to reduce ferric ions as well as protected liver tissues from lipid peroxidation as indicated by significantly reduced levels of MDA. However, M. whitei showed no significant serum urea and creatinine levels decrease. In conclusion, the phytochemical-rich M. whitei root extract demonstrated anti-diabetic, antioxidant, hypolipidemic and hepatoprotective effects in STZ-induced diabetic rats, highlighting its potential as a natural candidate for the management of DM and its complications.

ENVIRONMENTAL OCCURRENCE AND ECOTOXICOLOGICAL RISKS OF CONTAMINANTS OF EMERGING CONCERN IN THE RIVER ATHI BASIN, KENYA: ANALYTICAL AND KINETIC ADSORPTION STUDIES USING AGRICULTURAL WASTE BIOCHARS

2025-05-27T10:15:07Z

ENVIRONMENTAL OCCURRENCE AND ECOTOXICOLOGICAL RISKS OF CONTAMINANTS OF EMERGING CONCERN IN THE RIVER ATHI BASIN, KENYA: ANALYTICAL AND KINETIC ADSORPTION STUDIES USING AGRICULTURAL WASTE BIOCHARS CHEBII, FAITH JELAGAT Globally, the environmental occurrence of Contaminants of Emerging Concern (CECs) including Active Pharmaceutical Ingredients (APIs), Personal Care Products (PCPs) and pesticides has raised ecological and human health concerns. However, as the developed world make efforts to establish regulatory measures to mitigate their effects, developing nations including Kenya are lagging, partly due to unavailability of adequate data. Remediation of CECs in water can be achieved via photodegradation, advanced oxidation process, bioremediation, chemical degradation and activated carbon utilization. Adsorption, a cheaper and convenient alternative using the available agricultural wastes products, as biosorbent materials have not been fully explored. The objectives of this study were to determine multi-class CECs load and concentrations, determine ecotoxicological risks towards algae, Daphnia magna and fish, and potential point-of-use technologies via adsorption using Rice Husk Biochar (RHB), Avocado Seed Biochar (ASB)and Banana Peel Biochar (BPB). Water samples were collected from 24 sites across the River Athi basin area, Kenya. Extraction of water samples was done using Solid-Phase Extraction (SPE) and the CECs were analyzed using Ultra-High-Performance Liquid Chromatography coupled to High Resolution Orbitrap Mass Spectrometry (UHPLC-HRMS). The equilibrium adsorption isotherm studies were conducted for 86 CECs using ASB, BPB and RHB and the data was correlated using the non-linear curves of Langmuir and Freundlich rate equations. RHB was used in the adsorption kinetic studies for 86 CECs and the kinetic data acquired were correlated with the non-linear curves of Pseudo-First Order (PFO), Pseudo Second Order (PSO), Elovich and the Weber-Morris intraparticle diffusion models. The fitting performance of each model onto the kinetic data was guaranteed using adjusted R2 and the chi square values. The results of this analysis indicated that 57 CECs comprising 31APIs (0.4 ng L-1 – 142 µg L-1), 6 PCPs (0.7 – 570 ng L-1) and 20 pesticides (0.3 ng L-1 – 8.3 µg L-1) were detected. The maximum loads varied from 217 g day-1 (APIs) to 46 g day-1 (PCPs). Individually, Carbamazepine, Nevirapine, Sulfamethoxazole and DEET were the most ubiquitous CECs, with detection frequencies (DF) higher than 80%. The highest concentrations were observed at river sites that are heavily impacted by informal settlements, highlighting the critical role of slums in pollution of urban rivers. At least 8 CECs including Acetamiprid, Alachlor, Atrazine, Diuron, Nevirapine and Paracetamol showed potential risk to algae, Daphnia magna and fish, as exemplified by Risk Quotients (RQ) up to 174. Similarly, potential risk of antibiotic resistant bacteria development is evident due to exposure to Metronidazole, Sulfamethoxazole and Trimethoprim (RQ up to 64). Comparison of removal efficiencies of the CECs using the ASB, BPB and RHB showed that ASB and RHB had impressive % Removal efficiencies (94.0% - 98% and 87% - 99%) respectively compared to BPB (87% -93%). The lower %RE (% Removal Efficiencies) at lower concentrations for all the selected biochars is attributed to formation of bulky water clusters which may not be accommodated in the micropores on the surfaces of the biochars. The adsorption mechanism may be attributed to π-π electron donor- acceptor interaction, pore filling, ionic interactions and hydrogen bonding between the CECs molecules and the surfaces of the biochars. The kinetic adsorption analysis revealed that the kinetic data acquired for virtually 80% of the compounds were best described by the Elovich kinetic model, indicating that chemisorption was more pronounced on a heterogenous adsorbent surface as to physisorption and the intra – particle diffusion mechanisms. The R2 values approached unity and low Chi-square values approached zero. The equilibrium isotherm data fitted well both with Langmuir and Freundlich models with R2 approaching unity in most instances. However, Freundlich model had higher rate constants as to Langmuir models, an indicator that adsorption process was best described with a multilayer structure than the monolayer. There is a need to sensitize communities in informal settlements on proper waste disposal methods and the government agencies should include CECs in their monitoring schedule. ASB and RHB should be considered in the development of point-of-u

HEAVY METALS IN WATER, SOIL AND PUMPKIN (Cucurbita maxima) LEAVES FROM SHIYALU-LURAMBI AREA KAKAMEGA COUNTY KENYA: CONTAMINATION LEVELS AND SPECIATION ANALYSIS

2025-04-08T09:52:56Z

HEAVY METALS IN WATER, SOIL AND PUMPKIN (Cucurbita maxima) LEAVES FROM SHIYALU-LURAMBI AREA KAKAMEGA COUNTY KENYA: CONTAMINATION LEVELS AND SPECIATION ANALYSIS NEKESA, DOREEN MESO Pollution of the environment by heavy metals is a major global concern. Arsenic (As), cadmium (Cd), lead (Pb), nickel (Ni), copper (Cu), and zinc (Zn) present the greatest environmental threat because of their widest distribution and known toxic effects in humans, plants, animals and lower biota. The study was designed to assess the level of selected heavy metals in potable water, soils and Pumpkin leaves (Cucurbita maxima) samples to determine their availability and potential accumulation along the food chain. Samples for the field investigation were collected from randomly selected sites, transported to the research laboratory where they were treated and analyzed for Cd, Pb, Ni, Cu, and Zn using Atomic Absorption Spectroscopy (AAS). Arsenic was determined calorimetrically using Arsenic Test Kit (ATK). Inductive coupled plasma atomic emission spectroscopy (ICP-AES) was used to perform speciation studies for Cd and Pb in soil samples. It was found that whereas the As, Ni, Cu, and Zn concentrations in water, soil and plants were well within the respective World Health Organization (WHO) limits, both the Pb and Cd levels water (Pb -0.0925-0.5680 Cd -0.3911-0.5541); soil (Pb -1.2252-1.9279; Cd -0.6153- 0.7674-) and plants (Pb -1.0482-1.3892); Cd 0.1070-0.11833) respectively exceeded the permissible WHO standards for studied media, respectively. The Soil Pb and Cd were present in the bioavailable exchangeable fractions (0.42 mg/kg, 0.21 mg/kg) and reducible fraction (0.99 mg/kg, 0.28 mg/kg), respectively. Lead (Pb) and Cd in the soils posed significant risk of overexposure because of their high levels and speciation resulting in bioaccumulation and magnification in the plant tissues investigated. Because the overall toxic consequences of excessive exposure to these metals, it is recommended that the levels of heavy metals in plants, water, and soil in the affected areas need to be routinely assessed and measures taken to avert potential environmental and public health damage.

BACTERIOLOGICAL QUALITY OF FRESH MEAT SOLD WITHIN ELDORET TOWN

2025-04-02T09:55:06Z

BACTERIOLOGICAL QUALITY OF FRESH MEAT SOLD WITHIN ELDORET TOWN KOECH, EDWIN CHERUIYOT Meat is the primary source of proteins in many parts of Africa. In many cases however, it is major point of entry of many zoonotic diseases. Further, due to the long and many procedures involved in the meat industry, it is also implicated with many diseases associated with poor hygiene. The present study was carried out to assess the general microbiological quality of meat (beef, chevon and mutton) sold in Eldoret Town of Uasin Gishu County. The objectives of the study were; to investigate the physiological conditions of the meat, assessing the bacterial load of the meat, and biochemical characterization of selected bacterial pathogens found on the meat. Five major abattoirs were sampled for this study; Kaburwo in Langas, Maili Nne in Huruma, Cyrus in Munyaka, Eldoret main, and Teresia in Moiben representing all the major peri-urban centres of the Town. Five butcheries in the town were also selected for the study. The pH and temperatures of the carcasses were the physiological parameters measured and were recorded at the sampling sites. Meat samples were aseptically collected and taken in sterile bags and kept at 4˚C. One gram of each meat sample was mixed with 0.4 ml of 0.1% of buffered peptone water for 2 minutes. Serial dilutions were carried out and followed by plating via pour plate technique. The plates were incubated for 24 hrs at 37 ˚C after which total plate count was done to determine the bacterial load of the meat samples. Biochemical typing was done on pure isolates to determine the presence of Escherichia coli, Staphylococcus aureus, and Proteus vulgaris. PH values ranged from 5.5 to 6.77 with the pH of the meat obtained from butchery consistently registering low values compared to the ones from the abattoirs. Temperatures of the carcasses ranged from 23 ˚C to 26.95 ˚C. The lowest temperatures were obtained from the carcasses from Teresia abattoir. Statistical analysis of variance was used to determine level of signifance between the microbial load and factors; temperature and PH on meat sample collected. Correlation regression analysis was used to determine the influence of the physiological factors measured on the numbers of colony forming units(cfus). Statistical analysis was done using Ms Excel 2013. The meat in all the samples sites were found to be of poor bacteriological quality as the bacterial load was found to be higher than the recommended levels. The highest bacterial load was found in the carcasses in the butchery with an average of 19.8 cfus g/ml while the lowest was from the Maili Nne abattoir with an average of 4.9 cfus g/ml. Among the abattoirs, Teresia had the highest bacterial load of 9.2 cfus. Temperature was found to be positively correlated with cfu albeit weak (0.177) while pH was negatively correlated with the same (-0.478). Staphyloccocus aureus was the major pathogenic bacteria isolated from all the carcasses being at 26% of the isolated bacteria. Proteus vulgaris was at 11% and Escherichia coli at 8%. These differed from one sampling site to another but the order of abundance remained uniform. More public health education on the appropriate hygienic practices ought to be rolled out to help achieve a better microbiological quality status of the meat sold in Eldoret Municipality.

COMPUTER-BASED LABORATORY SIMULATIONS AND DEVELOPMENT OF INQUIRY SKILLS IN ELECTRO-CHEMISTRY IN SECONDARY SCHOOLS INSTRUCTION IN BOMET COUNTY

2024-01-31T07:27:46Z

COMPUTER-BASED LABORATORY SIMULATIONS AND DEVELOPMENT OF INQUIRY SKILLS IN ELECTRO-CHEMISTRY IN SECONDARY SCHOOLS INSTRUCTION IN BOMET COUNTY CHEPKORIR, SALOME Computer technology has advanced to the point where it can significantly enable inquiry learning to be used at various levels, and offer new tools for representing the nature of science in the classroom. Traditional education approaches which are teacher- centered are inadequate in developing scientific skills. The aim of this research was to examine the use of Computer-Based Laboratory Simulations (CBLs) in development of inquiry skills in electro- chemistry in secondary school chemistry instruction, Bomet County. Philosophical paradigm adopted in the study was positivism. It originated in the natural sciences and focuses much on scientific method of testing hypotheses which paves way for further investigations. The study was guided by constructivist theory of learning as advocated by Jean Piaget where learner participates actively in learning process to make meaning out of it. The study used Quasi-Experimental Research Design. Solomon-Four Non-equivalent Groups Design was applied. Four secondary schools in Bomet County were purposively sampled on the basis of availability of computers. Three hundred and sixty-nine subjects took part in the investigation. The four schools were allocated to control and treatment groups by simple random sampling method. All groups of students were taught similar chemistry content (electro-chemistry). However, experimental groups used CBLs approach while the control groups used regular teaching methods (RTM) including teacher demonstrations and lecture. The control group II and experimental group I were pre-tested prior to the implementation of the CBLs treatment. After four weeks, all the groups (four) were post-tested using the Students’ Chemistry Achievement Test (SCAT) which was authenticated by education experts and pilot tested before using to validate its reliability. Data was analysed using ANCOVA and one-way ANOVA at a significant level of coefficient alpha (α) equal to 0.05. The findings indicated that computer-based laboratory simulations assisted students in acquisition of scientific inquiry skills (P<0.05). These skills were hypothesis formulation, experimental design, data collection and analysis, critical thinking and problem-solving, collaboration, and communication. Computer based laboratory simulation had significant effect on chemistry achievement (P<.0.05). CBL was more effective and efficient method as opposed to traditional method. CBLs strategy as well as RTM had no significant difference based on gender (P>0.05). CBLs also had significant influence on attitude of students which enhanced performance in chemistry (P<0.05). The study concluded that CBLs had significant influence on achievement in chemistry since it assisted the learner to develop inquiry skills than RTM. The study recommended teacher training colleges and universities to include CBLs as part of their training programmes to empower teachers on the use of new digital approaches. The findings of this investigation will be beneficial to the curriculum developers, Kenya Institute of Curriculum Development (KICD) as well as chemistry instructors on the use of CBLs in teaching chemistry at secondary school level. There is need for a comparative study on learners’ motivation and self-concept in chemistry instruction through CBLs approach verses those taught through traditional methods.

INVESTIGATION OF Pavonia urens AS A POTENTIAL BIOSORBENT IN HEAVY METAL REMOVALTHROUGH COMPLEXATION

2024-01-30T07:38:54Z

INVESTIGATION OF Pavonia urens AS A POTENTIAL BIOSORBENT IN HEAVY METAL REMOVALTHROUGH COMPLEXATION RUTTO, SALINA Metal ion-related environmental pollution poses a possible risk to human life. This is a result of various chemical wastes being released into the environment after being treated in an affordable and effective manner. Several herbs have been reported for use in heavy metals removal in wastewater. This study aimed at investigating the phytochemicals present and demonstrating the possible use of Pavonia urens leaves as adsorbent material through formation of a complex with selected metals zinc (Zn), copper (Cu) and nickel (Ni) from aquatic environment. The plant was collected from Uasin Gishu County and air dried before crushing. The ground powder was soaked in organic solvents (hexane, ethyl acetate, and acetone) of increasing polarity each for 48 hours followed by filtration and drying. The Four fractions obtained were labelled 1A, 2A, 3A and 4A. The GC-Mass spectrometer (MS) identified compounds with functional groups hydroxyl (OH), amine (-NH), and (-COOH). The ability of Pavoniaurens to complex with bimetallic ions in aqueous solution was also investigated using UV-VIS spectrometry. The interaction of these ions with functional groups revealed by UV-VIS analysis showed higher complexation for copper ions and zinc was the least. Plant material containing known concentration of the given metal ions was prepared for analysis at a fixed pH of 6, temperature of 298 K and 300 K, dosage of plant material 1 g and agitation speed at 125 rpm. One gram (1 g) of plant material was introduced to every 100 mL solution. Change in concentration was noted at intervals of 20 minutes using Atomic Absorption Spectrometer (AAS) until the rate of biosorption was constant. With regard to contact time and temperature, the biosorption of Cu (II), Ni (II), and Zn (II) ions on Pavonia urens leaves in a batch system was examined. The first step of the biosorption, which was rapid, happened in two stages, with Zn being the least biosorbed while Cu was the most. Compared to the Freundlich and Temkin isotherms, the Langmuir isotherm more closely matched the experimental results. The adsorption reactions were demonstrated to be spontaneous because ΔG 0< 0, feasible and exothermic (ΔHo < 0). P. urens contains bioactive species and is a viable alternative as an economical, environmentally friendly bio-sorbent that may successfully complex with metal pollutants in aqueous solution. As a result, P. urens merits exploration in the search for key chemicals in drug discovery as well as for use as an adsorbent.