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University of Nairobi (2017)

Water Purification Using Oriang’ Women Clay Pots With N-doped Titanium Dioxide

Atieno, Maurine, O

Titre : Water Purification Using Oriang’ Women Clay Pots With N-doped Titanium Dioxide

Auteur : Atieno, Maurine, O

Université de soutenance : University of Nairobi

Grade : Master of Science in Environmental Chemistry 2017

Résumé
Our water bodies are constantly impacted by ecological and environmental changes emanating from natural and anthropogenic activities. A research conducted by UN indicated that about 2.2 million deaths occur yearly in the world linked to water-related diseases with majority being children. UN research also recorded that this situation will not get better, projecting that by the year 2025, potable water shortage will be experienced by 2.7 billion people. The aim of this research was to provide a low cost, low energy and low environmental impact water treatment solution, suitable for use in rural areas. This research focused on the application of modified TiO2 based photocatalyst for water purification process. N-doped TiO2 was prepared using Sol-gel process at room temperature using a precursor termed as titania- Titanium (IV) Isopropoxide and 25% Ammonia Solution as Nitrogen source. The synthesized compound was calcined at 673 K. The structure and morphology of N-doped TiO2 powder were examined using scanning electron microscopy (SEM). X-Ray Diffraction (XRD) was used to determine the particle size using the Debye-Scherrer‘s formula. The XRD gave a particle size of 18.372 nm. The synthesised N-doped TiO2 was dissolved into a paste using Polyethylene glycol and coated onto the inner surface of the pots, impregnated into the pore structure and tested against inactivation of E. coli and total coliforms. From the results, it indicated that N-doped TiO2 completely inactivated E. coli at 98.5% compared to un-doped TiO2 and SODIS at 81.1 and 76.7%, respectively. The N-doped TiO2 paste in pots that had >0.2 g of the photocatalyst deactivated E. coli to near 100% compared to 95.5% for the pot only. Further studies on the activity of the photocatalyst on photodecomposition of chemical using methylene blue and methyl red dyes showed that the photocatalyst achieved up to 99.6% and 97.8% degradation efficiency, respectively. The results suggest that photo catalytic decomposition of methylene blue followed first order with a deceptive reaction rate constant, k app. 1.9 X 10-2 min-1. Reaction kinetics was fitted into the Langmuir-Hinshelwood model for pseudo first order rates.

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