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Environmental pollution caused by antimony (Sb) has attracted worldwide attention recently. Here, we employed a flow-through electro-Fenton system for the rapid and efficient detoxification of highly toxic Sb(III). A FeOCl modified carbon nanotube (CNT) filter served as functional cathode, where FeOCl as nanocatalyst promoted the generation of HO by facilitating effective Fe 3+ /Fe 2+ cycling. Upon application of a proper potential, an ultra-rapid conversion of Sb(III) to less toxic Sb(V) can be achieved in situ just by a single-pass filtration (>99% within 2 s). Compared with the conventional batch reactor, the proposed system demonstrated ultra-rapid Sb(III) detoxification kinetics due to the convection-enhanced mass transport. The proposed flow-through E-Fenton system works effectively across a wide pH range (e.g., 3-9). EPR technique and radical quenching experiments indicate that HO and HO 2 were the dominant radical species responsible for Sb(III) detoxification. At -0.4 V vs. Ag/AgCl, a >96.4% Sb(III) conversion efficiency still can be achieved when challenged with 500 μg L -1 Sb(III)-spiked tap water. The as-produced Sb(V) can be removed effectively by another Sb(V)-specific CNT filter functionalized with nanoscale iron oxides. The outcome of this research provides a promising strategy by integrating state-of-the-art electro-Fenton, membrane separation, carboncatalysis and nanotechnology for detoxification of Sb(III) and other similar heavy metal ions in polluted water., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In this study, electrooxidation of the tetracycline hydrolysis products was investigated using a carbon nanotube (CNT) electrochemical filter and 4-epianhydrochlortetracycline (EACTC) as a model compound. Electrochemical filtration of 10 μmol L -1 EACTC at a voltage of 2.5 V and a flow rate of 1.5 mL min -1 (hydraulic residence time <3 s) provided an oxidation flux of 1251 ± 28 μmol h -1 m -2 . Replacement of the Ti cathode with a CNT filter cathode increased the EACTC oxidative flux by 1.3 fold at a voltage of 2.5 V. The electrochemical filtration process is effective for the degradation of EACTC and the reduction of the antimicrobial activity based on liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) analysis and luminescent bacteria test. The high oxidation flux within 300 min (1212-1263 μmol h -1 m -2 ) and affordable cost (0.25 kWh m -3 ) at a voltage of 2.5 V show the potential application of the electrochemical filtration system as a promising unit for EACTC degradation. These findings provided new insights into the rational design principles of novel continuous-flow filtration system aimed to efficiently remove hydrolysis products of the antibiotic tetracycline., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Water contamination from ammonia has recently became a global concern. Herein, a chloride-radical-mediated electrochemical filtration system has been developed towards effective and rapid conversion of ammonia to nitrogen (N 2 ). This continuous-flow system consists of a nanoscale tin oxide modified carbon nanotube (SnO 2 -CNT) anode and a Pd-Cu co-modified Ni foam (Pd-Cu/NF) cathode. The SnO 2 -CNT anode enables the Cl - oxidation to a chloride radical (Cl) at a proper anode potential (e.g., 2.5 V vs. Ag/AgCl) without severe self-oxidation. The macro-porous Pd-Cu/NF cathode further reduces anodic by-products (e.g., NO 3 and NO - and NO 2 . EPR and scavenging tests indicate that Cl was the dominant radical specie responsible for ammonia conversion. Anode potentials, chloride concentration, flow rate and solution pH were identified as key parameters affecting the overall conversion performance. The proposed continuous-flow system showed enhanced conversion kinetics as compared to the conventional batch reactor due to the convectively enhanced mass transport. This study provides new insight for the rational design of advanced continuous-flow systems towards ammonia decontamination from water bodies.- ) to N 2 . EPR and scavenging tests indicate that Cl was the dominant radical specie responsible for ammonia conversion. Anode potentials, chloride concentration, flow rate and solution pH were identified as key parameters affecting the overall conversion performance. The proposed continuous-flow system showed enhanced conversion kinetics as compared to the conventional batch reactor due to the convectively enhanced mass transport. This study provides new insight for the rational design of advanced continuous-flow systems towards ammonia decontamination from water bodies., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Ozonation at high doses is a costly treatment for oil sands process-affected water (OSPW) naphthenic acids (NAs) degradation. To decrease costs and limit doses, different peroxone (hydrogen peroxide/ozone; H 2 O 2 :O 3 ) processes using mild-ozone doses of 30 and 50 mg/L were investigated. The degradation efficiency of O x -NAs (classical (O 2 -NAs) + oxidized NAs) improved from 58% at 30 mg/L ozone to 59%, 63% and 76% at peroxone (1:1), 50 mg/L ozone, and peroxone (1:2), respectively. Suppressing the hydroxyl radical (•OH) pathway by adding tert-butyl alcohol did significantly reduce the degradation in all treatments, while molecular ozone contribution was around 50% and 34% for O 2 -NAs and O x -NAs, respectively. Structure reactivity toward degradation was observed with degradation increase for both O 2 -NAs and O x -NAs with increase of both carbon (n) and hydrogen deficiency/or |-Z| numbers in all treatments. However, the combined effect of n and Z showed specific insights and differences between ozone and peroxone treatments. The degradation pathway for |-Z|≥10 isomers in ozone treatments through molecular ozone was significant compared to •OH. Though peroxone (1:2) highly reduced the fluorophore organics and toxicity to Vibrio fischeri, the best oxidant utilization in the degradation of O 2 -NAs (mg/L) per ozone dose (mg/L) was observed in the peroxone (1:1) (0.91) and 30 mg/L ozone treatments (0.92). At n = 9-11, peroxone (1:1) had similar or enhanced effect on the O 2 -NAs degradation compared to 50 mg/L ozone. Enhancing •OH pathway through peroxone versus ozone may be an effective OSPW treatment that will allow its safe release into receiving environments with marginal cost addition., (Copyright © 2017 Elsevier Ltd. All rights reserved.)