Enhanced organic matter removal and fouling mitigation in seawater desalination using electrocoagulation pretreatment using ZnO coated Fe electrodes

Abstract

This study introduces a novel application of electrocoagulation (EC) as a pretreatment method for seawater desalination, uniquely focusing on reducing organic and biological fouling in reverse osmosis membranes. The EC process was investigated as an alternative to conventional approaches such as chemical coagulation, chlorination, and fouling inhibitors. EC was conducted in a batch cell using iron electrodes. The effectiveness of the EC process in removing organic matter from water was monitored by measuring absorbance UV254 and dissolved organic carbon (DOC), as well as total hardness. Various operational parameters, including mixing speed, current density, initial pH, and electrode spacing, were examined. Results demonstrated that increasing current density and decreasing pH enhanced the removal of organic matter from seawater via EC. The process achieved a 62% reduction in DOC and a 59.7% reduction in absorbance, indicating that higher current density is more favorable for these reactions. However, the reduction in total hardness was relatively low at approximately 11.2%, suggesting that EC is not suitable for reducing water hardness. Overall, the experimental findings highlight the high potential of electrocoagulation as a pretreatment method for mitigating organic and biological fouling of reverse osmosis membranes due to its effectiveness in removing dissolved organic matter and microorganisms from seawater.