Abstract
The use of reactive electrochemical membranes (REM) in flow-through mode during the anodic oxidation of organic compounds makes it possible to overcome the limitations of plate anodes: in the case of REM, the area of the electrochemically active surface is several orders of magnitude larger, and the delivery of organic compounds to the reaction zone is controlled by convective flow rather than diffusion. The main problem with REM is the formation of fouling and gas bubbles in the pores, which leads to a decrease in the efficiency of the process because the hydraulic resistance increases and the electrochemically active surface is shielded. This work aims to study the processes underlying the reduction in the efficiency of anodic oxidation, and in particular the formation of gas bubbles and the recharge of the REM pore surface at a current density exceeding the limiting kinetic value. We propose a simple one-dimensional non-stationary model of the transport of diluted species during the anodic oxidation of paracetamol using REM to describe the above effects. The processing of the experimental data was carried out. It was found that the absolute value of the zeta potential of the pore surface decreases with time, which leads to a decrease in the permeate flux due to a reduction in the electroosmotic flow. It was shown that in the solution that does not contain organic components, gas bubbles form faster and occupy a larger pore fraction than in the case of the presence of paracetamol; with an increase in the paracetamol concentration, the gas fraction decreases. This behavior is due to a decrease in the generation of oxygen during the recombination reaction of the hydroxyl radicals, which are consumed in the oxidation reaction of the organic compounds. Because the presence of bubbles increases the hydraulic resistance, the residence time of paracetamol—and consequently its degradation degree—increases, but the productivity goes down. The model has predictive power and, after simple calibration, can be used to predict the performance of REM anodic oxidation systems.
Highlights
IntroductionThe amount of organic waste, including biorefractory waste, has grown exponentially
Over the past decades, the amount of organic waste, including biorefractory waste, has grown exponentially
Up to ten percent of these pollutants end up in wastewater, which makes the problem of removing organic compounds—which are resistant to traditional biological methods of wastewater treatment—urgent
Summary
The amount of organic waste, including biorefractory waste, has grown exponentially. Anodic oxidation in particular [5,6], are the most promising solutions, and are considered by the scientific community to be next-generation technologies for the purification of waste and natural waters from organic pollutants. The anodic oxidation process allows one to mineralize organic compounds through a combination of direct electron transfer and oxidation by hydroxyl radicals, which are generated during the water discharge on the anode surface and are highly reactive to most toxic organic pollutants [7]. Most of the organic substances contained in wastewater, including aromatic compounds, undergo mineralization [8,9,10], and with certain parameters of the system, one can achieve 100% degradation, but at the same time, energy consumption naturally increases [11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
