The development of an electrochemical chip for the in-situ production of active chlorineFilip Ambrož
, 2016, master's thesis
Abstract: Active chlorine is a highly efficient disinfectant used for sanitizing purposes in swimming pools, food-processing facilities and hospitals. It is also known for being the most powerful reagent in applications related to water disinfection. Currently, the most widely-used method for chlorine production is the chlor-alkali process. Despite significant improvements in electrode materials, used in combination with the process optimization that has taken place in recent decades, the production still consumes very high amounts of energy. Alternatives, such as electrochemical methods, require platinum-group metals (PGMs) that are expensive. In this study, a continuous-flow device was fabricated, involving an electrochemical chip for treating a fluid which uses an integrated silver(I) chloride photoelectrode. The device comprised of an inlet and outlet for the treated fluid, together with a flow path between them where the photoelectrode was located. This low-cost and recyclable chip included a treatment mode of operation, for treating a fluid that moves along the flow path, and a regeneration mode of operation, for regenerating the substrate. The photoelectrode was electrochemically activated, and was recycled at low potentials between 0.2 V and 0.4 V vs Ag/AgCl (3 M KCl) in an electrolyte solution containing chloride ions. The conducted experiments showed that the layer of silver(I) chloride (AgCl) on the photoelectrode decomposed upon exposure to light into silver (Ag) and chlorine (Cl2); thus, active chlorine (HOCl) was formed when the photoelectrode was in contact with water. However, degradation effects were observed over time, meaning that the photoelectrode was not able to be fully regenerated. Nevertheless, a cost-effective alternative for chlorine generation based on a light-driven microfluidic device is proposed here for the first time.
Keywords: water chlorination, methyl orange, Ag/AgCl photoelectrode, microfluidic device, PDMS, photolithography
Published in DKUM: 05.09.2016; Views: 1277; Downloads: 109
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