Chemistry
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Item PHYTOCHEMICAL ANALYSIS, IN VITRO TESTING OF ANTIBACTERIAL PROPERTIES, ANTI-INFLAMMATORY ACTIVITY, AND CYTOTOXICITY OF AQUEOUS AND DICHLOROMETHANE LEAF EXTRACTS OF Solanum incanum AND Tamarindus indica(Chuka University, 2023-10) NGURARI SAMSON WAINAINAThe prevalence of bacterial infections and inflammatory-related diseases is increasing. As an alternative, the pharmaceutical sector is currently focusing on studying medicinal plants to generate alternative therapies for these health concerns. Solanum incanum and Tamarindus indica are among the plant species utilized in traditional medicine to address these issues. Most conventional drugs used to manage inflammation and bacterial infections have side effects, while some are expensive, hence the need to have alternative plant-based therapies. Additionally, there is limited information on the potency of Solanum incanum and Tamarindus indica, which is vital in process of commercializing its active metabolites to improve disease management. Therefore, this study analyzed phytochemicals present in aqueous and dichloromethane leaf extracts of the two plants and tested their antibacterial, anti-inflammatory, and cytotoxic properties. The phytochemical analysis was done using standard chemical tests followed by Gas Chromatography-Mass Spectroscopy of dichloromethane extracts. The antibacterial activity of the extracts was tested against Escherichia coli, Salmonella typhi, and Staphylococcus aureus using disc diffusion method, minimum inhibitory Concentration, and minimum bactericidal concentrations assays. The anti-inflammatory potency of the extracts was tested using an Erythrocyte stabilization assay, while the toxicity of the extract was tested using brine shrimp lethality tests. Phytochemical analysis indicated presence of flavonoids, tannins, saponins, phenols, and alkaloids in all the plant extracts. Additionally, the T. indica dichloromethane and S. incanum water extracts had no glycosides, while anthraquinones were absent in all the extracts. The antibacterial assay revealed significant difference in antibacterial activity between the plant extracts at different concentrations. The Minimum Inhibitory Concentrations of T. indica extracts ranged between 62.5 μg/mL and 125 μg/mL, while those of S. incanum ranged between 62.5 μg/mL and 250 μg/mL. The Minimum Bactericidal Concentration of both plants ranged between 125 μg/mL and 500 μg/mL. The S. incanum dichloromethane extracts had the highest percentage erythrocyte stabilization at 1000 μg/ml, 57.64 ±13.90%, while S. incanum water extract had the lowest stabilization at 2000 μg/ml, 19.06 ±14.43%. T. indica dichloromethane extract has the highest toxicity (LD50 of 113.57 μg/mL) while S. incanum DCM extract was the least toxic (LD50 of 2341 μg/mL). The plant extracts have demonstrated the potential of being used for therapeutic purposes after further analysis for the identification of the active compounds. Therefore, this research provides preliminary data on their antibacterial and anti-inflammatory activity and cytotoxicity of the extracts, which is foundational for further research.Item SYNTHESIS AND CHARACTERIZATION OF IRISH POTATO PEELS POWDER-NANOSILICA COMPOSITE FOR THE DEGRADATION OF RHODAMINE BLUE AND DICLOFENAC(Chuka University, 2023-10) MUTIE JOSEPH NZUKUIn today's world, finding safe drinking water has become a major concern. Many contaminants, including dyes and pharmaceuticals, are discharged directly or indirectly into bodies of water without sufficient treatment, rendering the water unsafe for human consumption. To safeguard the environment and human health, harmful toxins must be removed from wastewater. Various technologies have been used to address this issue. Adsorption on activated carbons is a widespread technique in wastewater treatment, but the exorbitant cost of ordinary activated carbons limits its use. Several agricultural waste products are currently being used inefficiently and have the potential to be transformed into important adsorbents such as composites. Because of its nano-sized inorganic filler, nano-silica has exceptional characteristics such as large surface area, mesoporous structure, biocompatibility, versatile pore size, modifiability, and polymer hybridizability over common composites. Irish potato peel powder is a natural binder that works well in composite materials. Since most composite materials are poorly distributed, this study concentrated on utilizing Irish potato peel powder and nano-silica from rice husks to produce a composite of Irish potato peel powder and nano-silica. This study aimed to synthesize, characterize and make Irish potato peel powder/nano-silica composite in the degradation of rhodamine blue and diclofenac. Silica nanoparticles were mixed with Irish potato peel powder in the ratios 1:1, 1:2, 2:1, 4:1, and 5:1, respectively. Glutaraldehyde was added to the mixture as a binder. The following functional groups was detected in the composite's Fourier Infrared spectrum: C=C, O-Si-O, and Si-OH, which corresponded to peaks at 1645.35 cm-1, 1104.29 cm-1, and 3439.23 cm-1, respectively, and are responsible for the adsorption of Rhodamine Blue and Diclofenac. The XRF analysis showed that silica accounted for a large proportion in the composite, which determined the mixing ratio of RHNS and IPPP (4:1). The composite surface area was 100.6328 m2/g, with a single point surface area of 97.4036 m2/g, according to BET-BJH surface characterization. The synthesized composite was amorphous in nature, as shown by the XRD pattern, which has a strong broad peak between 200 and 250 (2θ). The adsorption capacity of RB and DCF by the composite was optimal at pH 4 and 2, respectively, an initial concentration of 1 mg/L and 40 mg/L, respectively, an adsorbent dose of 0.1 g, and a 240 rpm stirring speed. The removal efficiency of the composite was 99.39% for DCF and 97.57% for RB. The rhodamine blue removal best fit the Freundlich isotherm in the used composite adsorbent with R2 = 0.996, while the DCF removal suited the Langmuir isotherm model the best with R2 = 0.901. The kinetic data were pseudo-second-order (R2 = 0.9989 for RB and 0.849 for DCF), which was more suitable for explaining the adsorption rate. Fineness, surface area, and vacancy concentration are all associated with better adsorption capacity.Item LEVELS OF SELECTED PHTHALATES FROM WASTEWATER TREATMENT PLANTS IN LAKE VICTORIA CATCHMENT AREA AND THEIR ADSORPTION ONTO WATER HYACINTH BIOCHAR(Chuka University, 2020-12) OGORA, ELKANAH NYAKWAMAEndocrine disrupting chemicals (EDCs) disturb the endocrine system’s functionality causing negative effects on health in an organism and its progeny. They can interfere with natural hormone cycles in humans or animals, potentially affecting metabolism, development, reproduction and growth. Phthalates are among the many examples of EDCs, which have been used as plasticizers for longtime around the world. Due to their extensive usage, they are found in many surface waters, sludge and waste waters. The occurrence of phthalates in water, and their exposure to non-target organisms cause adverse effects such as congenital anomalies, endocrine disruption and chronic toxicity. This study determined residual levels of three phthalates namely; dimethyl phthalate (DMP), benzyl butyl phthalate, (BBP) and bis(2-ethylhexyl) phthalate (BEHP) in wastewater sampled from wastewater treatment plants (WWTPs) of Nyalenda, Homabay and Kisii during wet and dry seasons. The wastewater samples were extracted and cleaned by solid phase extraction cartridges (SPE) ready for high performance liquid chromatography (HPLC) for quantitative analysis. Most of the sites sampled had detectable levels of DMP, BBP and BEHP in wastewater. High concentrations were detected during wet season compared to dry season in all sampled sites. Nyalenda WWTP recorded the highest concentrations of phthalates than Homabay and Kisii WWTPs. The concentrations of all selected phthalates were recorded highest at the inlet sampling points from all WWTPs, in both seasons sampled. Almost all the selected phthalates were below the limit of quantification (LOQ) at the outlet sampling points of Homabay and Kisii WWTPs in both seasons. The residue levels obtained showed significant differences at 5% confidence limits with zcal for all phthalates in all WWTPs less than the critical value (Zcritical = 1.96). Therefore, the null hypothesis was rejected. Consequently, a cost-effective technique of removing DMP, BBP and BEHP from their solutions using water hyacinth biochar (WHB) as an adsorbent was investigated. A mass of 0.1 g of WHB both before and after adsorption was used for characterization process. Elemental analysis of WHB was determined using XRF (EDXRF), the XRD patterns were obtained using bruker operating with Cu Kά(λ = 1.541nm) and samples scanned in coupled TwoTheta/Theta. The FTIR spectra were obtained between 4000cm-1 and 400cm-1 using Shimadzu type. The adsorption process was done using an orbital shaker agitated at 125 rpm and residual levels determined using the HPLC. The optimum conditions obtained from the adsorption of DMP, BBP and BEHP onto WHB were as follows; equilibrium time was 25 minutes, maximum adsorbate concentration adsorbed at 0.1 g of WHB was 4 mg/L, temperature of 298 K was appropriate and 0.8 g of WHB was effective for the adsorption of above 67% of 10 mg/L of each selected phthalate. The kinetic data fitted the pseudo second order model with regression values for DMP, BBP and BEHP found to be 0.9987, 0.9984 and 0.9986, respectively. The Freundlich model demonstrated to be a good model for fitting the adsorption data, which was attributed to heterogenous distribution of charged functional groups at adsorption sites of WHB’s surface. The calculated thermodynamic parameters, namely; change in Gibb’s free energy (ΔG), change in enthalpy (ΔH) and change in entropy (ΔS) showed that the adsorption process was favorable, exothermic, spontaneous and of a physical type. This was due to the fact that all of them were negative values. Dimethyl phthalate was the most effectively removed by WHB as adsorbent. The removal efficiency decreased with increasing molecular weight of the phthalates. The findings demonstrated that WHB is a good low cost and environmentally adsorbent for removal of phthalates from water.Item ASSESSMENT OF QUALITY OF SHALLOW WELLS WATER IN CHUKA SUB-COUNTY, KENYA(Chuka University, 2020-12) Rugendo, Edith MwendeGroundwater from shallow wells is an important source of water for domestic and agricultural uses in Chuka Sub-County. However, most shallow wells in Chuka Sub-County are undocumented because approval is not required to sink a shallow well. Groundwater from these shallow wells is therefore susceptible to contamination by both geogenic and anthropogenic sources. This study was conducted to determine the quality of shallow wells water in Chuka Sub-County. Samples were collected from twenty shallow wells in Chuka Sub-County during the dry and wet seasons. The temperature, pH and conductivity were determined in situ using a conductivity meter. The concentration of cations in the water samples was determined using an Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) system. The concentration of chloride and nitrate ions in the water samples were determined using the argentometric and the spectrophotometric method, respectively. The concentration of sulphate ions was determined using a turbidimetric method while the concentration of phosphate ions was determined using a colorimetric method. The data obtained were subjected to ANOVA to test the significance differences using R-3.5.2. Mean comparison was achieved through LSD. The temperatures of the waters were significantly higher during the dry season. The pH of water in most shallow wells during the wet season was within the limits set by KEBS and WHO. However, shallow well water at Karandini (T15) was highly acidic (pH of 3.95) during the wet season. During the dry season, the shallow well waters were slightly acidic (4.42 - 6.44) except for the shallow wells at Ndagani market (T11), whose water was alkaline (pH = 8.75). The shallow wells water at site T11 had remarkably higher conductivities than the other shallow wells in the study area during both the wet (1150 μs/cm) and the dry (1208 μs/cm) seasons. The concentrations of macro-cations (Ca2+ and Mg2+) were higher during the dry season. The concentrations of the trace and toxic cations differed significantly across sites and seasons but were within the limits set by KEBS and WHO. The concentrations of anions (NO3-, SO42-, Cl- and PO43-) were within the limits set by KEBS and WHO for portable water. Groundwater from most shallow wells in Chuka Sub-County is generally safe for domestic uses but regular monitoring for quality is recommended because, the concentration of nitrate in several wells during the dry season was within the range that causes chronic health effects including colorectal, ovarian, thyroid, kidney and bladder cancers.