Efficient organic pollutants conversion and electricity generation for carbonate-containing wastewater based on carbonate radical reactions initiated by BiVO4-Au/PVC system

Simultaneously disinfection of amoebae, endosymbiotic bacteria, and resistance genes using a novel two-electron water oxidation strategy

Amoebae, which serve as important vectors for various pathogenic bacteria, are ubiquitous in natural and artificial water systems. Their robust survival capabilities and protective characteristics render conventional disinfection methods largely ineffective. Moreover, amoeba cells provide an ideal environment for the replication and transfer of antibiotic resistance genes, posing a significant threat to human health and safety. In this study, an in-situ activation system for electrocatalytic water oxidation was developed. This system effectively inactivates amoeba spores and their intracellular symbiotic bacteria while simultaneously reducing the abundance of resistance genes through the generation of hydroxyl radicals (•OH) and carbonate free radicals (•CO3-). The results demonstrated a 99.9 % inactivation rate for amoeba spores and a 99.999 % inactivation rate for intracellular bacteria. In addition, the prevalence of resistant genes in bacteria within amoebae, specifically including sul1 (sulfonamide resistance), tetA (tetracycline resistance), blaFOX (cefoxitin resistance), arsB (arsenic resistance), czcA (cadmium resistance), and copA (copper resistance), was significantly reduced by approximately 16 %-62.6 %. Therefore, this study introduces a new technology capable of simultaneously treating amoeba spores, intracellular bacteria, and resistance genes, which holds significant importance for reducing the spread of resistant genes and enhancing public health safety.

CuOx-ZrO2-TiOx Composite Interfaces with Strong Lewis Acid Activity for Electrooxidation of Methane to Acetic Acid

The electrochemical conversion of methane (CH4) to valuable oxygenates is an attractive approach to utilize abundant natural gas, however, the chemical inertness of CH4 and its low solubility in electrolytes impede effective electrooxidation. Enhancing the adsorption and activation of CH4 on catalysts is crucial for electrocatalytic methane oxidation reaction (eMOR). In this study, we developed the CuOx-ZrO2-TiOx composite catalyst for the selective electrooxidation of CH4 to CH3COOH. The ZrO2-TiOx was in situ synthesized on Ti substrates via the hydrothermal reaction of TiO2 nanowires with H2C2O4 and Zr(NO3)4. Subsequently, CuOx was uniformly disposed on ZrO2-TiOx with the assistance of polyvinylpyrrolidone (PVP) and citric acid. The prepared electrode achieves the Faradaic efficiency (FE) of 60.1% for CH3COOH at the current density of 10.8 mA cm-2, corresponding to the generation rate of 3312.5 µmol gcat -1 h-1. Mechanism studies confirm that the synergistic effect of CuOx and ZrO2-TiOx interfaces enhances the efficiency of eMOR. CuOx oxidizes H2O to produce hydroxyl radicals (*OH) and ZrO2-TiOx interfaces with strong Lewis acid activity adsorb and activate CH4. The CuOx and ZrO2-TiOx interfaces synergistically oxidize CH4 to generate a series of intermediates (*CH3, *CH3O, *CH2O, *COOH), promoting C-C coupling to produce CH3COOH.

Triple-Phase Interfacial Freestanding Fluffy Pine Needle Structures for Efficient Self-Powered Photoelectrocatalysis

Approximately 2 billion people still lack access to clean drinking water. Extensive efforts are underway to develop semiconductor photocatalysts for water disinfection and environmental remediation, but conventional liquid-solid diphase interfacial photocatalysts face challenges like low diffusion coefficients and limited solubility of dissolved oxygen. This study introduces freestanding copper oxide fluffy pine needle structures (CO-FPNs) with tunable water pollutants-gas-solid (WGS) triple-phase interfaces that enhance oxygen enrichment and reactive oxygen species (ROS) production. Three differently structured CO-FPNs-microdendrites, hierarchical dendrites, and nanowires-are designed. The hierarchical CO-FPN/WGS, predominantly in the Cassie-Wenzel coexistence state, showed a 1.81- to 1.91-fold higher reaction rate than the micro- and nanostructured CO-FPNs due to increased interfacial O2 levels and high adsorption capability. Under illumination, the hierarchical CO-FPN/WGS achieved 99.999% sterilization by preventing pathogen adhesion and enhancing ROS generation. Additionally, a self-powered photoelectrocatalytic system is constructed using nickel-iron oxide-deposited bismuth vanadate (NiFeO/BiVO4) with hierarchical CO-FPN/WGS, achieving 1.45 times higher than the hierarchical CO-FPN/WGS alone, due to superior oxidation kinetics of NiFeO/BiVO4 and improved oxygen reduction via atmospheric oxygen from the hierarchical CO-FPN/WGS. This study demonstrates the first example of a triple-phase interfacial self-powered platform for efficient photoelectrocatalysis.

Ultrasonic treatment of endocrine disrupting compounds, pharmaceuticals, and personal care products in water: An updated review

Pharmaceuticals, personal care products (PPCPs), and endocrine-disrupting compounds (EDCs) have seen a recent sustained increase in usage, leading to increasing discharge and accumulation in wastewater. Conventional water treatment and disinfection processes are somewhat limited in effectively addressing this micropollutant issue. Ultrasonication (US), which serves as an advanced oxidation process, is based on the principle of ultrasound irradiation, exposing water to high-frequency waves, inducing thermal decomposition of H2O while using the produced radicals to oxidize and break down dissolved contaminants. This review evaluates research over the past five years on US-based technologies for the effective degradation of EDCs and PPCPs in water and assesses various factors that can influence the removal rate: solution pH, temperature of water, presence of background common ions, natural organic matter, species that serve as promoters and scavengers, and variations in US conditions (e.g., frequency, power density, and reaction type). This review also discusses various types of carbon/non-carbon catalysts, O3 and ultraviolet processes that can further enhance the degradation efficiency of EDCs and PPCPs in combination with US processes. Furthermore, numerous types of EDCs and PPCPs and recent research trends for these organic contaminants are considered.

High-performance bismuth vanadate photoanodes cocatalyzed with nitrogen, sulphur co-doped ferrocobalt-metal organic frameworks thin layer for photoelectrochemical water splitting

In this study, we prepare a highly efficient BiVO4 photoanode co-catalyzed with an ultrathin layer of N, S co-doped FeCo-Metal Organic Frameworks (MOFs) for photoelectrochemical water splitting. The introduction of N and S into FeCo-MOFs enhances electron and mass transfer, exposing more catalytic active sites and significantly improving the catalytic performance of N, S co-doped FeCo-based MOFs in water oxidation. The optimized BiVO4/NS-FeCo-MOFs photoanode exhibits impressive results, with a photocurrent density of 5.23 mA cm-2 at 1.23 V vs. Reversible Hydrogen Electrode (RHE) and an incident photon-to-charge conversion efficiency (IPCE) of 74.4 % at 450 nm in a 0.1 M phosphate buffered solution (pH = 7). These values are 4.84 times and 6.2 times higher than those of the original BiVO4 photoanode, respectively. Furthermore, the optimized BiVO4/NS-FeCo-MOFs photoanode demonstrates exceptional long-term stability, maintaining 96 % of the initial current after five hours.

Performance and mechanism of sodium percarbonate (SPC) enhancing short-chain fatty acids production from anaerobic waste activated sludge fermentation

A novel pretreatment technique (i.e., using Sodium percarbonate, SPC) to improve the short-chain fatty acids (SCFA) production waste activated sludge (WAS) was proposed in this study. Results indicated that the maximum SCFA production of 1605.7 mg COD/L and acetic acid of 52.9% were attained at 0.2 g SPC/g TSS, being 8.4 and 2.8 times of the control (191.3 mg COD/L and 19%), respectively. Meanwhile, the optimal time for SCFA accumulation was decreased from 6d (control) to 4d (0.2 g/g TSS). Mechanism explorations unraveled that SPC largely accelerated WAS solubilization and enhanced the bioavailability of organics released from WAS. It improved enzymatic activities related to hydrolysis and acidogenesis, while suppressed the Coenzyme F₄₂₀ responsible for SCFA consumption. Illumina MiSeq sequencing analysis showed that SPC substantially enhanced the relative abundances of hydrolytic and/or acid-forming microbes. Furthermore, CO₃^- and O₂^- were the key factors to production enhancement in SPC-involved sludge fermentation.

Understanding the effects of mineral water matrix on degradation of several pharmaceuticals by ultrasound: Influence of chemical structure and concentration of the pollutants

Degradation of seven relevant pharmaceuticals with different chemical structures and properties: acetaminophen (ACE), cloxacillin (CXL), diclofenac (DCF), naproxen (NPX), piroxicam (PXC), sulfacetamide (SAM) and cefadroxil (CDX), in distilled water and mineral water by ultrasound was studied herein. Firstly, proper conditions of frequency and acoustic power were determined based on the degradation ability of the system and the accumulation of sonogenerated hydrogen peroxide (24.4 W and 375 kHz were found as the suitable conditions for the sonochemical treatment of the pharmaceuticals). Under such conditions, the pharmaceuticals degradation order in distilled water was: PXC > DCF ~ NPX > CXL > ACE > SAM > CDX. In fact, the initial degradation rate showed a good correlation with the Log P parameter, most hydrophobic compounds were eliminated faster than the hydrophilic ones. Interestingly, in mineral water, the degradation of those hydrophilic compounds (i.e., ACE, SAM and CDX) was accelerated, which was attributed to the presence of bicarbonate ions. Afterwards, mineral water containing six different initial concentrations (i.e., 0.331, 0.662, 3.31, 16.55, 33.1, and 331 µM) of selected pharmaceuticals was sonicated, the lowest concentration (0.331 µM) always gave the highest degradation of the pollutants. This result highlights the great ability of the sonochemical process to treat bicarbonate-rich waters containing pollutants at trace levels, as pharmaceuticals. Finally, the addition of ferrous ions to the sonochemical system to generate a sono-Fenton process resulted in an acceleration of degradation in distilled water but not in mineral water. This was attributed to the scavenging of sonogenerated HO• by bicarbonate anion, which decreases H₂O₂ accumulation, thus limiting the Fenton reaction.

Scaling-up of microbial electrosynthesis with multiple electrodes for in situ production of hydrogen peroxide

Microbial electrosynthesis system (MES) has recently been shown to be a promising alternative way for realizing in situ and energy-saving synthesis of hydrogen peroxide (H₂O₂). Although promising, the scaling-up feasibility of such a process is rarely reported. In this study, a 20-L up-scaled two-chamber MES reactor was developed and investigated for in situ and efficient H₂O₂ electrosynthesis. Maximum H₂O₂ production rate of 10.82 mg L⁻¹ h⁻¹ and cumulative H₂O₂ concentration of 454.44 mg L⁻¹ within 42 h were obtained with an input voltage of 0.6 V, cathodic aeration velocity of 0.045 mL min⁻¹ mL⁻¹, 50 mM Na₂SO₄, and initial pH 3. The electrical energy consumption regarding direct input voltage was only 0.239 kWh kg⁻¹ H₂O₂, which was further much lower compared with laboratory-scale systems. The obtained results suggested that the future industrialization of MES technology for in situ synthesis of H₂O₂ and further application in environmental remediation have broad prospects.

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Up-scaled microbial electrosynthesis with multiple electrodes to synthesize H₂O₂

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The H₂O₂ yield was higher than that of laboratory-scale systems using graphite cathode

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Energy consumption was lower than that of laboratory-scale (bio)electrochemical systems

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Systematic evaluation of the influence of operating parameters on H₂O₂ production