Browsing by Author "Kinyua, Esther Mbuci"

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    Clarification of colloidal and suspended material in water using triethanolamine modified maize tassels
    (Kenyatta University, 2016-07) Kinyua, Esther Mbuci
    Suspended particles in water are a major concern in global pollution management. These particles are very small and are evenly distributed in the water. They originate from factors such as decomposing organic materials and algae. They are a significant factor in the water clarity, as they limit penetration of sunlight; provide a good environment for bacterial growth, contributing to fouling and unpleasant odours that compromise aesthetic appreciation of the water. They also complex with metals in the soil making them soluble and hence available for poisoning. Thus there is need for the removal of suspended matter in water. Removal of suspended solids is normally achieved through sedimentation or filtration. However, some suspended colloidal particles are very stable in water and cannot settle while others are able to pass through the filter because of their small sizes hence difficult to remove. In this regard, alternative methods for their removal need to be explored. This study investigated the use of a soluble polycation made from modifying maize tassels with triethanolamine to form a quaternary ammonium compound. The modified quaternary ammonium compound becomes permanently charged hence is suitable for flocculation of suspended particles in water. The modified maize tassels material was characterized using Fourier-transform infrared (FTIR). It was found that the triethanolamine was chemically anchored within the cellulose structure of the maize tassels. Clarification parameters such as settling time, reagent dosage and pH were investigated. This study reports that the best clarification was obtained at a pH of 6.0. The optimal flocculent dosage for modified flocculent that could clarify 250 ml of water having a turbidity of 12 NTU (Nephelometric Turbidity Units) was found to be 3.5 ml which clarified turbid water in less than 30 minutes. Therefore, this implies that the flocculent has a potential application for the remediation of turbid waters by aggregating suspended matter to clarify water.
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    Clarification of colloidal and suspended material in water using triethanolamine modified maize tassels
    (Springerlink, 2015) Kinyua, Esther Mbuci; Mwangi, Isaac W.; Wanjau, Ruth N.; Ngila, J.C.
    Suspended particles in water are a major concern in global pollution management. They affect the appreciation of water due to clarity, photosynthesis, and poor oxygen environment rendering water unsuitable for aquatic animals. Some suspended materials contain functional groups capable of forming complex compounds with metals making them available for poisoning. Such material promotes the growth of bacteria and fouling that give rise to unpleasant taste and odor of the water and thus requires removal. Removal of suspended solids is normally achieved through sedimentation or filtration. However, some suspended colloidal particles are very stable in water and cannot settle while others are able to pass through the filter due to small size, hence difficult to remove. This study investigated the use of triethanolamine-modified maize tassels to form a flocculent for their removal. The modified maize tassels were characterized using Fourier transform infrared (FTIR), and it was found that the triethanolamine was anchored within the cellulose structure of the maize tassels. Clarification parameters such as settling time, reagent dosage, and pH were investigated. The best clarification was at a pH of 6.0 with clearance being less than in 30 min. The optimal flocculent dosage was found to be 3.5 ml of the material, showing that the material has a potential of enhancing clarity in polluted water
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    Remediation of Domestic Wastewater by Electro- Oxidation of Dissolved Organic Substances
    (Kenyatta University, 2025-11) Kinyua, Esther Mbuci
    Water pollution poses a significant threat globally, rendering vital water resources unsuitable for sustaining life. Detecting harmful substances dissolved in water can be done by observing changes in its colour, indicating the presence of pollutants like chemicals, trash, bacteria, and parasites. These contaminants alter water's appearance, affecting its clarity and overall quality. Basic methods to improve water clarity involve coagulation and settling techniques, but these can leave residues that lead to health issues. Efforts to treat wastewater have used strong oxidizing agents to eliminate pollutants, but this approach introduces secondary pollutants in treated water. Hence, there's a need for cost-effective techniques for domestic wastewater treatment. This study explores an electrochemical method to remove dissolved organic substances from water. It involves generating reactive oxidizing species at an electrode to interact with these substances. Two types of anode electrodes were used. A platinum electrode and a dimensionally stable anode (DSA) coated with iron (III) doped titanium dioxide on graphite. The incorporation of iron (III) ions within the structure and the crystal form of the material were both confirmed using SEM-EDX and XRD respectively. The experimental setup featured a two-chamber cell divided by a proton exchange membrane (PEM) made from a conducting polyaniline polymer. The polymeric material was characterized using Fourier Transformation Infrared spectroscopy (FTIR). The analysis confirmed the presence of conjugated bonds that can enable conduction of electricity by the organic material. The PEM was casted onto a fritz grid separating the two compartments of the cell. The setup for the oxidation process was done for the treatment of the domestic wastewater to enable a green chemistry treatment method without generating secondary pollutants. Treatment occurred in the anodic chamber where oxidizing species were generated. The platinum anode reduced oxygen from the air, while the DSA facilitated electron and holes generation through photo-oxidation, effectively degrading organic matter. Excess protons were discharged to the cathode through the casted PEM, separating the two halves of the reactor. The cell successfully purified a green leafy solution at 4.5 g/L concentration within 72 hours. Potential measurements reached a high voltage of about 105 mV within the initial 150 minutes of the oxidation process. Monitoring degradation through potential measurements and kinetics confirmed a gradual reduction in dispersed matter concentration over time. These findings illustrate the potential of this degradation process for remediating domestic wastewater, enabling its reuse at the source.