Journal Article

Electrophoresis‐Enhanced Delivery of Rhamnolipid‐Coated Ozone Micro‐Nano Bubbles for Remediating Heterogeneous Aquifer

Shentu, Jiali, Zhang, Jingxian, Qi, Shengqi, Shen, Dongsheng, Chu, Wangwei, Li, Lili, Fu, Qingyun, Long, Yuyang, Sun, Qinqin, Liu, Weilin, Luo, Jian, Lu, Li

2026

Overview

Remediating organic pollutants in heterogeneous aquifer presents a significant challenge due to the limited penetration of chemical reagents into these zones. Ozone micro‐nano bubbles, with their small diameters, can transport to low‐permeability zone (LPZ) and oxidize target contaminants; however, their mobility is often hindered by attachment to porous media surfaces. This study investigated the use of electrokinetic (EK) remediation to enhance the transport of rhamnolipid‐coated ozone micro‐nano bubbles (ROMNB). Column experiments showed that applying an electric field of 3 V/cm increased outlet ozone concentrations by 23.2∼24.7%, corresponding to a 25.9∼60.0% increase in nanobubble density at the outlet. A 2D heterogeneous sand tank experiment further demonstrated that, when the ROMNB injection point was positioned near the cathode, total toluene removal in the LPZ reached 89.3%, 21.8% higher than without EK. The analysis of oxidation byproducts showed that 43.2% and 0.075% of carbon in toluene from LPZ were converted to CO2 and benzoic acid, respectively, indicating the effective oxidation of toluene. Numerical modeling accurately reproduced the spatial distribution of residual toluene with the average error of 9.5%, confirming that electrophoresis significantly improved ROMNB penetration into LPZ. Furthermore, when the applied voltage gradient exceeded 0.5 V/cm, the simulated total toluene removal percentage in LPZ stabilized at 90.4∼94.1%, suggesting that the voltage could be optimized to reduce energy consumption. These findings highlight the potential of integrating ROMNB with EK for effective remediation of organic contaminants in low‐permeability subsurface environments.

• Publisher: John Wiley & Sons, Inc
• Subject: Aquifers / Benzoic acid / Bubbles / Carbon dioxide / Cathodes / Charged particles / Contaminants / Contamination / Electric fields / Electric potential / Electrophoresis / Electrophoretic mobility / Energy consumption / Experiments / Integrated approach / Numerical models / Organic chemicals / Organic contaminants / Oxidation / Ozone / Permeability / Porous media / Reagents / Remediation / Rhamnolipids / Spatial distribution / Surfactants / Toluene / Voltage / Water