Disinfection of Escherichia coli by a Reactive Electrochemical Membrane System Involving Activated Carbon Fiber Cloth (ACFC)

Abstract

This study examined a novel reactive electrochemical membrane (REM) system with activated carbon fiber cloth (ACFC) serving simultaneously as the anode and the membrane to effectively disinfect water that was filtered through the device. An Escherichia coli strain was inoculated to water as a model pathogen. The influence of REM operation parameters, including the number of ACFC layers, voltage, flow rate and operation time, was evaluated. Up to 7.5 log unit reduction of E. coli concentration in water was achieved at the optimal treatment condition, while the energy consumption was 1.5 kWh/m3 per log unit reduction of E. coli. This makes it possible to use this ACFC-based REM technology for point-of-use water disinfection to provide clean water for underdeveloped regions. Further tests by free radical probing, Linear Scan Voltammetry (LSV) and Scanning Electron Microscopy (SEM) suggest that the disinfection involved the filtration/retention of bacteria on ACFC and attack by reactive oxygen species generated electrochemically on the anode.

Electrified Membranes for Water Treatment Applications

“…Indirect oxidation depends on electrogeneration of highly reactive species (e.g., • OH and Cl • ) on anodic membranes through electrooxidation of water molecules or chloride ions. Compared to direct oxidation, indirect oxidation exhibits superior bacteria inactivation, which is likely ascribed to one or more of these pathways: (i) reactive species oxidize proteins and lipids in the cell membrane leading to leakage of intracellular substances (e.g., electrolytes, enzymes); (ii) reactive species damage key metabolism enzymes (e.g., catalase and superoxide dismutase) and inhibit cell growth; − (iii) the electric field adversely impacts cell membrane potential, which hinders synthesis of adenosine triphosphate and interferes with cell activity. , In general, biofouling control in anodic EMs primarily depends on ROS/RCS generation, which increases as the applied electric potential is increased . However, increasing electric field strength increases side reactions, such as the OER and the formation of chlorinated DBPs, thereby drastically decreasing EM current efficiency.…”

Effect of pH on Escherichia coli Removal by Electrocoagulation and Elimination Kinetics after Treatment

“…Electrocoagulation is a very efficient process for the removal of E. coli from water, which can be optimized by changing the electrical and physicochemical parameters, such as charge density, current density, electrode material, supporting electrolyte, initial pH, and others. [3,[7][8][9][10]. In most cases, it takes quite a long treatment time to achieve the total removal of E. coli from water, which results in greater energy consumption, and therefore, a high cost of treatment.…”

“…One of the emerging technologies that proved its efficiency against a broad spectrum of microorganisms is electrochemical disinfection. It has gained increasing attention as an alternative to the conventional methods of disinfection since it is environmentally friendly and is known to inactivate a wide variety of microorganisms, from bacteria to viruses and algae [3][4][5][6][7][8][9][10].…”

Membrane Separation Coupled with Electrochemical Advanced Oxidation Processes for Organic Wastewater Treatment: A Short Review

“…Bacterial inactivation and wastewater disinfection by REMs were conducted by Liang, Huang, and Lei. They all observed remarkable performance, with a result of 97.2% for Liang’s study and 100% for the rest [ 94 , 95 , 96 ]. Moreover, REMs have performed well in the removal of low-concentration and trace pollutants.…”