Protrudent Iron Single-Atom Accelerated Interfacial Piezoelectric Polarization for Self-Powered Water Motion Triggered Fenton-Like Reaction.

Water in motion presented in natural systems contains a rich source of renewable mechanical energy. Harvesting this water energy to trigger the generation of reactive oxygen species (ROS) for water purification is a desirable yet underexplored solution. Herein, the authors report a self-powered water motion triggered Fenton-like reaction system for wastewater treatment through the piezo-activation of peroxymonosulfate (PMS). Isolated protrudent Fe single atomic sites are immobilized on the surface of molybdenum disulfide (MoS2 ) nanosheet to improve piezoelectric polarization of MoS2 , to accelerate piezoelectric charge separation, and to enhance PMS activation for water purification. ROS (• OH, SO4•- , O2•- , and 1 O2 ) generation for PMS piezo-activation are observed, and different water contaminants, including antibiotic, industrial chemicals, and dyes are efficiently removed under the natural water fluid. Aimed at solving concurrent issues of environmental pollution and energy crisis, this study provides a pathway for single atomic-mediated piezo-activation of Fenton-like reactions through ambient self-powered water motion for water purification.

Identification of Environmental Liquid-Crystal Monomers: A Class of New Persistent Organic Pollutants-Fluorinated Biphenyls and Analogues-Emitted from E-Waste Dismantling.

Liquid-crystal monomers (LCMs), especially fluorinated biphenyls and analogues (FBAs), are considered to be a new generation of persistent, bioaccumulative, and toxic organic pollutants, but their emissions from liquid-crystal display (LCD)-associated e-waste dismantling remain unknown. To fill this knowledge gap, a broad range of 46 LCMs, including 39 FBAs and 7 biphenyls/bicyclohexyls and analogues (BAs), were investigated by a dedicated target analysis in e-waste dust samples. Of 39 target FBAs, 34 were detected in LCD dismantling-associated dust. Among these 34 detectable FBAs, 9 were detected in 100% of the samples and 25 were frequently detected in >50% of the samples. The total concentrations of these 34 FBAs (∑34FBAs) detected in LCD e-waste dust were in the range of 225-976,000 (median: 18,500) ng/g, significantly higher than those in non-LCD e-waste dust (range: 292-18,500, median: 2300 ng/g). In addition to FBAs, six of seven BAs were also frequently detected in LCD e-waste dust with total concentrations (∑6BAs) of 29.8-269,000 (median: 3470) ng/g. Very strong and significant correlations (P < 0.01) were identified in all frequently detected LCMs, indicating their common applications and similar sources. Our findings demonstrate that e-waste dismantling contributes elevated emissions of FBAs and BAs to the ambient environment.

Occurrence and Maternal Transfer of Multiple Bisphenols, Including an Emerging Derivative with Unexpectedly High Concentrations, in the Human Maternal-Fetal-Placental Unit.

In this study, a set of 15 bisphenols (BPs) and one emerging derivative (4-hydroxyphenyl 4-isoprooxyphenylsulfone, BPSIP) were analyzed in 60 pairs of maternal plasma, cord plasma, and placenta samples from pregnant women in South China. A total of 4 of the 15 target BPs, i.e., BPA, bisphenol S (BPS), bisphenol AF (BPAF), and bisphenol E (BPE), were frequently detected in the three human biological matrixes. The derivative BPSIP was identified in all maternal plasma samples at unexpectedly high levels, second only to BPA. The concentrations of bisphenols in maternal plasma were slightly higher than in cord plasma for BPA, BPS, and BPE but much higher for BPSIP and much lower for BPAF, indicating that the five frequently detected bisphenols have different placental transfer behaviors. The placental transfer efficiencies (PTEs) of BPA, BPS, and BPE were similar, which were significantly higher than the PTE of BPSIP. The PTE of BPAF was much higher than other BPs, indicating its strong maternal transfer and high fetal accumulation. The PTEs of bisphenols were structure-dependent, and passive diffusion was suggested as the potential mechanism of placental transfer. Significant concentration correlations of the five major bisphenols between maternal plasma and cord plasma were observed (p < 0.05). Meanwhile, significant associations of BPAF concentrations in maternal/cord plasma with some maternal characteristics and adverse birth outcomes were also identified (p < 0.05).

Prevalence, Biotransformation, and Maternal Transfer of Synthetic Phenolic Antioxidants in Pregnant Women from South China.

Synthetic phenolic antioxidants (SPAs) have been identified as an emerging group of contaminants in recent years. However, there are significant gaps in our knowledge of human prenatal exposure to these synthetic chemicals. In this study, a set of eight SPAs and four major transformation products (TPs) were systematically analyzed in matched samples of maternal plasma, cord plasma, and placenta from a population of pregnant women. Five of the eight target SPAs and all four target TPs were frequently detected in the maternal-placental-fetal unit, indicating prenatal exposure to SPAs and the transfer of SPAs across the placenta. In the three matrices, 2,6-di-tert-butyl-hydroxytoluene (BHT), 2,4-di-tert-butylphenol (DBP), and 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (AO 2246) were identified as the most abundant SPAs, while 2,6-di-tert-butyl-1,4-benzoquinone (BHT-Q) and 2,6-di-tert-butyl-4-hydroxy-4-methyl-2,5-cyclohexadienone (BHT-quinol) were identified as the predominant TPs of BHT. In the maternal plasma, concentrations of both BHT-Q and BHT-quinol were significantly correlated with BHT (p < 0.001), suggesting that the two TPs mainly originated from the biotransformation of BHT itself in pregnant women. The transplacental transfer efficiencies (TTEs) of the SPAs and TPs were structure-dependent and generally less than 1. Significantly higher TTEs for four target TPs than their parent BHT were identified. To our knowledge, this study provides the first evidence that SPAs and TPs transfer across the placenta in pregnant women.

Performance and Mechanism of Piezo-Catalytic Degradation of 4-Chlorophenol: Finding of Effective Piezo-Dechlorination.

Piezo-catalysis was first used to degrade a nondye pollutant, 4-chlorophenol (4-CP). In this process, hydrothermally synthesized tetragonal BaTiO3 nano/micrometer-sized particles were used as the piezo-catalyst, and the ultrasonic irradiation with low frequency was selected as the vibration energy to cause the deformation of tetragonal BaTiO3. It was found that the piezoelectric potential from the deformation could not only successfully degrade 4-chlorophenol but also effectively dechlorinate it at the same time, and five kinds of dechlorinated intermediates, hydroquinone, benzoquinone, phenol, cyclohexanone, and cyclohexanol, were determined. This is the first sample of piezo-dechlorination. Although various active species, including h+, e-, •H, •OH, •O2-, 1O2, and H2O2, were generated in the piezoelectric process, it was confirmed by ESR, scavenger studies, and LC-MS that the degradation and dechlorination were mainly attributed to •OH radicals. These •OH radicals were chiefly derived from the electron reduction of O2, partly from the hole oxidation of H2O. These results indicated that the piezo-catalysis was an emerging and effective advanced oxidation technology for degradation and dechlorination of organic pollutants.

Ba substituted SrTiO3 induced lattice deformation for enhanced piezocatalytic removal of carbamazepine from water.

Removal of pharmaceuticals and personal care products (PPCPs) from water by mechanical energy-driven piezocatalysis is a promising technology for environmental remediation that highly depends on the design of efficient piezocatalyst. In this study, Ba-substituted SrTiO3 piezoelectric materials were constructed and used for piezocatalytic degradation of carbamazepine (CBZ) from water. The Ba0.5Sr0.5TiO3 (BSTO-2) achieved the optimal performance, exhibiting 94.5% removal efficiency for CBZ (10 mg/L) after 30 min in the presence of BSTO-2 (0.5 g/L) and ultrasonic vibration (40 kHz, 100 W) with the minimal energy consumption. The kinetic rate constant was up to 0.106 min-1, which were 1.86 and 2.08 times as high as that of pure SrTiO3 and BaTiO3, respectively. The enhanced piezocatalytic activity was attributed to its distorted structure and modified conductivity, resulting in a higher piezoelectric response and faster interfacial charge transfer. The involved reactive species, the effects of operational condition (catalyst dosage, CBZ concentration, solution pH, anions, water matrices and different pollutants), and the possible degradation products and their toxicity were discussed in detail. The work is of great significance to develop highly efficient piezocatalysts and highlights the potential of piezocatalysis in water remediation.

Enhanced utilization efficiency of peroxymonosulfate via water vortex-driven piezo-activation for removing organic contaminants from water.

The efficient activation and utilization of peroxymonosulfate (PMS) in PMS-based advanced oxidation processes is a high-priority target for the removal of organic contaminants. This work introduces a water vortex-driven piezoelectric effect from few-odd-layered MoS2 into the PMS activation to remove benzotriazole (BTR) and other organic contaminants from the water. Approximately 91.1% of BTR can be removed by the MoS2 piezo-activated PMS process with a reaction rate constant of 0.428 min-1, which is 2.09 times faster than the sum of the individual MoS2, water vortex, and piezocatalysis rates. Meanwhile, the PMS utilization efficiency reached 0.0147 in the water vortex-driven piezo-activation system, which is 3.97 times that of the sum from the vortex/PMS and MoS2/PMS systems. These results demonstrate that the presence of MoS2 under a water vortex can trigger a piezoelectric potential and generate abundant free electrons to activate PMS to generate various active species for degradation of organic contaminants.

Piezo-activation of peroxymonosulfate for benzothiazole removal in water.

Piezoelectricity, as a kind of physical phenomenon, is a coupling between a material's mechanical and electrical behavior. Herein, the local accumulated charges on the surface of piezoelectric material were used to break OO bond of peroxymonosulfate (PMS) to induce its activation for the benzothiazole (BTH) removal. Taking BaTiO3 as a model piezocatalyst, up to 97 % of BTH was degraded within 30 min in BaTiO3/PMS/force system, which was respective 40 %, 79 %, 83 % higher than that in BaTiO3/force piezocatalysis, force/PMS oxidation, and BaTiO3/PMS adsorption. A significant synergistic effect was observed since the reaction rate constant of BaTiO3/PMS/force was 3 times higher than the sum of those later three processes. The possible activated mechanism was proposed based on reactive species analysis, DFT calculation and LCMS determination. The stability of the piezocatalyst and the treatment performance for real wastewater were studied to investigate the potential in practical applicability. All the results demonstrated that the BaTiO3 piezoelectricity can efficiently activate PMS to enhance BTH removal, which is a promising strategy for PMS activation, as well as a valuable insight for the piezoelectrical application in wastewater remediation.

Reusable magnetic Ag/Fe, N-TiO2/Fe3O4@SiO2 composite for simultaneous photocatalytic disinfection of E. coli and degradation of bisphenol A in sewage under visible light.

A visible-light-driven and magnetic photocatalyst Ag/Fe,N-TiO2/Fe3O4@SiO2 (AgFeNTFS) was synthesized through a multi-step method. AgFeNTFS was tested for the photocatalytic disinfection of Escherichia coli (E. coli) and degradation of bisphenol A (BPA) under visible light irradiation, separately and simultaneously. The results showed that a 6.3-log reduction in cell density of E. coli was achieved and BPA (2 mg/L) was completely removed by AgFeNTFS in the separated photocatalytic processes within 120 min. In the simultaneous process, the photocatalytic disinfection of E. coli was not influenced in the presence of BPA, but the efficiency of BPA degradation was dropped by 10%. This was likely due to the competition for the same dominant reactive species of O2- and H2O2 between E. coli and BPA in the simultaneous process, as evidenced by the scavenger study and the interactions between the pollutants and AgFeNTFS. Moreover, the simultaneous photocatalytic activity of E. coli disinfection and BPA degradation by AgFeNTFS was investigated in the sewage obtained from a local wastewater treatment plant. The photocatalysis treated sewage could meet with the local disinfection discharge standard with a 3-log reduction of E. coli after 90 min, and a complete removal of BPA was achieved simultaneously after 360 min. Moreover, AgFeNTFS showed high magnetic separation efficiency and had a good reusability over three cycles for the simultaneous photocatalytic disinfection and degradation of BPA in both synthetic water and sewage. This study provides insights on the application of a reusable magnetic photocatalyst for simultaneous disinfection and degradation of BPA in sewage.

Tuning role and mechanism of paint sludge for characteristics of sewage sludge carbon: Paint sludge as a new macro-pores forming agent.

For the first time, paint sludge waste (PS) was used as a pore forming agent in the preparation of sewage sludge derived carbon (SC). The tuning role and mechanism of PS for characteristics of SC were explored. It was found that a sludge carbon (SCPS-Zn) with rich macro-, meso- and micro- porous could be produced by one-step pyrolytic process of sludge in the presence of PS and ZnCl2. Its surface area could reach as high as 680.5m2g-1 as 88.4 times and 4.8 times of sludge carbon without addition of PS and ZnCl2 (SC) and only addition of ZnCl2 (SCZn), respectively. The macro- pores fabricated by PS provided much inner-space for ZnCl2 to generate meso- and micro- porous, leading to a hierarchical porous structure. SCPS-Zn showed a high adsorption capacity of 685.4mgg-1 for Chrysophenine, which is 1.3 and 1.7 times that of SCPS and SCZn respectively. The adsorption difference could be simply attributed to the fact that the great molecules were difficult to enter micro- pores of SCZn. It was also found that the difference was also dependent on orientation of Chrysophenine, which was related to pH value of solution.