Developing a low-pressure and super stable electrochemical tubular reactive filter: Outstanding efficiency for wastewater purification

This research mainly focused on the development of strong oxidizing and ultra-stable flow-through porous anode materials for electrochemical reactive filter technology. In this study, a novel ultrahigh-throughput tubular reactive filter coated with β-PbO2 electrocatalytic layer (β-PbO2-TRF) was developed, which has super stability and reactivity, outperforming currently reported flow-through porous anode materials. The permeation rate of β-PbO2-TRF was achieved at 59.2 m3/(m2·h·bar) and expected service lifetime was as long as 253 years. Safety assessment test results showed no detectable Pb ions in solution was released from the β-PbO2 electrocatalytic layer. For electrochemical reactivity, the kinetic constants of convection-enhanced oxidation for Fe(CN)64– and oxalic acid were observed at 6.5 × 10−4 and 4.2 × 10−4 m/s, respectively, which are among the highest reported in the literature. Additionally, hydroxyl radical (•OH) formed at a rate of 4.72 × 10−9 mol/(cm2·min) upon 0.59 mA/cm2, much higher than that for Ti4O7 materials. For norfloxacin and sulfamethoxazole at trace level concentration in surface water and wastewater final effluent, a log removal only needs 2.0–5.4 s real residence time. The corresponding energy costs were estimated as 0.005–0.024 kWh/m3. This highly scalable β-PbO2-TRF technology presents a new and cost-effective option for one-step deep purification of wastewater effluent.