Mass transfer phenomenon in baffled reactor using electro-peroxone process: Effects of electrode arrangement and flow rate

Using green nanocomposite containing eggshell in the electroperoxone process in a baffled reactor to remove the emerging tetracycline pollutant

This study examined the eradication of Tetracycline hydrochloride (TCH) antibiotic, an emerging pollutant, by utilizing eggshell membrane activated carbon (EMAC) and magnetite (Fe3O4) nanocomposite in conjunction with the electroperoxone process employing the One Factor at a Time method (OFAT) in a baffled reactor. The nanocomposite was synthesized through the hydrothermal method using an autoclave, and its properties were assessed via XRD, FTIR, FESEM, EDAX Mapping, BET, and VSM analyses. The findings revealed that under optimal conditions (including a pollutant concentration of 300 mg/L, a natural pH of 6.2, an ozone consumption rate of 0.28 g/h, a nanocomposite concentration of 0.2 g/L, a flow intensity of 0.5 A, a wastewater recirculation flow rate of 8 L/h, and a 0.1 M Na2SO4 electrolyte concentration), 95.9%, 76.4%, and 53.4% of pollutants, COD, and TOC were respectively eliminated after 90 min. Additionally, the reusability of the nanocomposite was evaluated over five usage periods, during which the process efficiency decreased from 95.9% to 83.1%. In short, this study proved that EMAC/Fe3O4 nanocomposites are promising electroperoxone catalysts due to their low cost, excellent stability and reusability, environmental compatibility, and superior catalytic activity for TCH antibiotics removal.

Efficient multi-stage electrochemical flow-through system for refractory organic pollutant treatment: Kinetics, mass transfer, and thermodynamic analysis

Improving the kinetics rate and mass transfer is essential for expanding the potential of electrochemical technologies in wastewater treatment. The electrochemical flow-through configuration promises a high oxidation efficiency and low energy consumption. We aimed to provide a thorough understanding of the enhanced kinetics, mass transfer, and thermodynamic parameters during the degradation of amoxicillin (AMX) in a multi-stage flow-through (MSFT) system using porous Ti-ENTA/SnO2-Sb anodes. All operating conditions strongly influenced the kinetics of AMX degradation and followed pseudo-first-order rate kinetic model (R2 > 0.85), with the highest kobs of 0.228 min-1 at high temperature (318 K). In comparison to the flow-by mode, the AMX removal rate in the three-stage flow-through mode was greatly enhanced by 70%, exhibiting the superior capacity of a porous anode. This system exhibited outstanding performance regarding the high kinetics rate and mass transfer rate (km), which increased by factors of 3.46 and 10.74, respectively, obtained in the flow-by mode. It also revealed that •OH generation was 5.64 times higher, and the EE/O was 19.89-fold lower than those in flow-by mode. Temperature plays a vital role in the reaction process, and thermodynamic features found the positive enthalpy (ΔHo) of +27.06 kJ mol-1, signifying the process was endothermic. A Hatta number (Ha) of >0.02 at all temperatures proved this finding, confirming an undeniable role in mass transfer. Finally, these findings reveal the system's performance and offer the possibility of establishing a multi-stage flow-through for wastewater treatment.