Disinfection of Seawater and Its Neutralization Using Seawater Battery

Abstract

Seawater disinfection is a commonly used technology in many functional systems operated in the seawater environment to prevent biofouling due to the formation of biofilms by microorganism growth, which induces an operational problem in the long-term. there are three kinds of conventional disinfection technologies, physical (UV), chemical (ozone and Cl), and electrochemical ones with no use of chemical additive. Conventional disinfection methods have many issues to be resolved, such as high energy consumption, low disinfection efficiency, and an additional neutralization process before discharging the treated water. Therefore, it is highly required to develop an energy-efficient disinfection technology which enables a high disinfection efficiency, as well as simple neutralization process to remove toxic disinfectants, such as total residual oxidant (TRO) in the treated water. In this work, we introduce a new type of electrochemical disinfection system, which functions both seawater disinfection and neutralization without any chemical treatments, named as the combined system for disinfection and neutralization (CSDN). By employing a rechargeable seawater battery system[1-3], the CSDN conducts seawater disinfection and the neutralization of remained TRO during charge and discharge processes, respectively. The disinfection efficiency of total chlorine (TC), such as HOCl and OCl, produced during charging is evaluated by using Escherichia coli and Enterococcus aquamarines. The remained TRO in disinfected seawater is removed by discharging, where the TRO (TC) are reduced into chloride ions, while providing electricity to external loads. The mechanisms behind the generation and neutralization of TRO are discussed. The proposed CSDN would provide an effective solution to lower energy consumption for seawater disinfection through the battery technology and an interdisciplinary approach to connect between the disinfection and electrochemical energy storage technologies. References : [1] Kim, J.-K.; Mueller, F.; Kim, H.; Bresser, D.; Park, J.-S.; Lim, D.-H.; Kim, G.-T.; Passerini, S.; Kim, Y. Rechargeable-Hybrid-Seawater Fuel Cell. NPG Asia Mater. 2014, 6, e144. [2] Kim, H.; Park, J.-S.; Sahgong, S. H.; Park, S.; Kim, J.-K.; Kim, Y. Metal-Free Hybrid Seawater Fuel Cell with an Ether-Based Electrolyte. J. Mater. Chem. A 2014, 2, 19584−19588. [3] Kim, J.-K.; Mueller, F.; Kim, H.; Jeong, S.; Park, J.-S.; Passerini, S.; Kim, Y. Eco-friendly Energy Storage System: Seawater and Ionic Liquid Electrolyte. ChemSusChem 2016, 9, 42−49.