Hydrophobic Ce-doped β-PbO2-SDS anode achieving synergistic effects for enhanced electrocatalytic oxidation of As(III)

Electrochemical degradation of Cephalexin on Ti/TiO2/βPbO2 anode modified by sodium dodecyl sulfate

The possible environmental dangers of antibiotics include excessive use, wastewater discharge, and resistance to biodegradability. Therefore, efficient and environmentally friendly methods to remove such pollutants are necessary to preserve global ecosystems and human life. Electrochemical oxidation using lead-based electrodes is an effective approach for the treatment of resistant organic pollutants. In this research, a Ti/TiO2-βPbO2 electrode was synthesized for the electrochemical degradation of Cephalexin. To increase the efficiency and stability of the electrode, βPbO2 electrodeposition was performed in the presence of sodium dodecyl sulfate. The performance of the electrode in the degradation and mineralization of Cephalexin was evaluated using cyclic voltammetry and differential pulse voltammetry, and the maximum degradation efficiency and maximum COD removal of 97.60% and 70.27%, respectively, were obtained. In addition, the degradation mechanism was studied using liquid chromatography coupled with tandem mass spectrometry. The findings indicated that the Ti/TiO2-βPbO2 electrode exhibited desirable electrocatalytic performance in the degradation and mineralization of Cephalexin. Therefore, wastewater contaminated with antibiotic residues can be treated before discharging into the sewage system and the environment by this approach.

New Ti/CNT/CNT-Ce-PbO2 anode synergy peroxymonosulfate activation for efficiently electrocatalytic degradation of p-aminobenzoic acid

Increased levels of p-aminobenzoic acid in aquatic environments, primarily utilized as UV filter in sunscreens, poses a serious threat to human and ecosystem health, while there is a dearth of exhaustive researches pertaining to the efficient and cost-effective elimination of p-aminobenzoic acid. Herein, a Ti/SnO2-Sb/CNT-α-PbO2/CNT-Ce-β-PbO2, referred to Ti/CNT/CNT-Ce-PbO2 electrode was constructed by incorporating CNTs into the middle layer of PbO2 electrode, and simultaneously doping CNTs and Ce in the active layer. A series of tests signify that the target electrode is successfully fabricated, which exhibits higher particle density and smaller particle size, as well as exceptional degradation performance for p-aminobenzoic acid with a degradation rate of 99.7% within 30 min coupling with peroxymonosulfate activation. The optimal degradation performance was observed at a PMS dosage of 0.07 g, Na2SO4 concentration of 0.05 mol L-1, current density of 120 mA cm-2, and initial pH value of 6.94. Capture experiments, electron spin resonance test, liquid chromatography-mass spectrometry analysis, toxicity assessment and theoretical calculation were performed to clarify the main activate radicals, degradation pathways and intermediate toxicity. This study provides a new anode material, and conducted the first exploration of electrocatalysis integrating peroxymonosulfate activation for degradation p-aminobenzoic acid.

PANI/GO and Sm co-modified Ti/PbO2 dimensionally stable anode for highly efficient amoxicillin degradation: Performance assessment, impact parameters and degradation mechanism

The abuse and uncontrolled discharge of antibiotics present a severe threat to environment and human health, necessitating the development of efficient and sustainable treatment technology. In this work, we employ a facile one-step electrodeposition method to prepare polyaniline/graphite oxide (PANI/GO) and samarium (Sm) co-modified Ti/PbO2 (Ti/PbO2-PANI/GO-Sm) electrode for the degradation of amoxicillin (AMX). Compared with traditional Ti/PbO2 electrode, Ti/PbO2-PANI/GO-Sm electrode exhibits more excellent oxygen evolution potential (2.63 V) and longer service life (56 h). In degradation experiment, under optimized conditions (50 mg L-1 AMX, 20 mA cm-2, pH 3, 0.050 M Na2SO4, 25 °C), Ti/PbO2-PANI/GO-Sm electrode achieves remarkable removal efficiencies of 88.76% for AMX and 79.92% for chemical oxygen demand at 90 min. In addition, trapping experiment confirms that ·OH plays a major role in the degradation process. Based on theoretical calculation and liquid chromatography-mass spectrometer results, the heterocyclic portion of AMX molecule is more susceptible to ·OH attacks. Thus, this novel electrode offers a sustainable and efficient solution to address environmental challenges posed by antibiotic-contaminated wastewater.

Efficient stabilization of arsenic migration and conversion in soil with surfactant-modified iron-manganese oxide: Environmental effects and mechanistic insights

The use of iron-manganese oxide (FMO) as a promising amendment for remediating arsenic (As) contamination in soils has gained attention, but its application is limited owing to agglomeration issues. This study aims to address agglomeration using surfactant-modified FMO and investigate their stabilization behavior towards As and resulting environmental changes upon amendments. The results confirmed the efficacy of surfactants and demonstrated that cetyltrimethylammonium-bromide-modified FMO significantly reduced the leaching concentration of As by 92.5 % and effectively suppressed the uptake of As by 85.8 % compared with the control groups. The ratio of the residual fraction increased from 30.5-41.6 % in unamended soil to 67.9-69.2 %. The number of active sites was through the introduction of surfactants and immobilized As via complexation, ion exchange, and redox reactions. The study also revealed that amendments and the concentration of As influenced the soil physicochemical properties and enriched bacteria associated with As and Fe reduction and changed the distribution of C, N, Fe, and As metabolism genes, which promoted the stabilization of As. The interactions among cetyltrimethylammonium bromide, FMO, and microorganisms were found to have the greatest effect on As immobilization.

B4C/Ce co-modified Ti/PbO2 dimensionally stable anode: Facile one-step electrodeposition preparation and highly efficient electrocatalytic degradation of tetracycline

The application of PbO2 for electrochemical oxidation technology is limited by its low electrocatalytic activity and short service life. Herein, based on the facile one-step electrodeposition, we prepared a boron carbide (B4C) and cerium (Ce) co-modified Ti/PbO2 (Ti/PbO2-B4C-Ce) electrode to overcome these shortcomings. Compared with Ti/PbO2 electrode, the denser surface is displayed by Ti/PbO2-B4C-Ce electrode. Meanwhile, electrochemical characterization indicates that the introduction of B4C and Ce significantly enhance the electrochemical performance of PbO2 electrode. In degradation experiments, under optimized conditions (current density 20 mA cm-2, pH 9, 0.15 M Na2SO4 and 30 °C), the fully degradation of tetracycline (TC) can be completed within 30 min. Furthermore, the trapping experiment demonstrates that ∙OH and SO4·- radicals have a synergistic effect in the degradation process of TC. Based on results of liquid chromatography-mass spectrometer, the generated ·OH preferentially attacks amides, phenols and conjugated double bond groups in TC. Importantly, Ti/PbO2-B4C-Ce electrode maintains a constant degradation efficiency even after 10 recycling tests, and its service life is 2.4 times of traditional Ti/PbO2 electrode. Hence, Ti/PbO2-B4C-Ce electrode is a promising electrode for degradation of organic wastewater containing amides, phenols, and conjugated double bond groups.