Development of a Solar Photocatalytic Reactor for Sustainable Water Purification Open Access
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As lack of access to clean drinking water continues to be a problem, especially in rural areas and developing countries, the challenge of finding innovative ways to treat drinking water in secluded areas with few resources must be met. Additionally, the presence of persistent and emerging organic micropollutants and pathogens further challenges the safety of treated water. A potential solution is the solar-energy-enabled photocatalysis, a sustainable advanced oxidation process that can destruct organic micropollutants and inactive pathogens. Because operating a photocatalytic reactor can be solely dependent on renewable solar energy, the process is sustainable and can be used in areas where electricity and chemicals are not readily accessible. The purpose of this research project is to develop a solar photocatalytic reactor for sustainable water purification. Among various types of photoreactor designs, the compound parabolic collector (CPC) design was chosen due to its capability to collect high solar radiation at any angle of acceptance, its ability to operate either on pilot-scale or industrial-scale applications, and its low fabrication, operation, and maintenance costs. Graphitic carbon nitride(g-C3N4 ) was used as the photocatalyst for contaminant removal. With the optimized CPC reactor design, chitosan beads were applied as the support to immobilize the photocatalyst (g-C3N4). The photocatalytic reactivity was then evaluated in a 3D printed CPC reactor under simulated sunlight (xenon lamp, AM 1.5 G optical filter) for the removal of a model contaminant and emerging persistent micropollutants in buffer solutions. The g-C3N4 chitosan beads with an optimized size and g-C3N4 loading showed a promising photocatalytic activity toward contaminants degradation. Meanwhile, the g-C3N4 chitosan beads exhibited selective contaminants degradation that could be attributed to the different interactions between chitosan with contaminants. Overall, the optimum CPC reactor design with the immobilization of photocatalyst on chitosan beads will promote the practical application of solar photocatalytic water treatment technology for rural areas and developing countries.