LaOCl:Eu super(3+) nanofibers, nanobelts and nanotubes were prepared by electrospinning combined with a double-crucible chlorination technique using NH sub(4)Cl as chlorinating agent. Different ...morphologies of LaOCl:Eu super(3+) were obtained via adjusting some of the electrospun parameters. X-ray powder diffraction analysis indicated that LaOCl:Eu super(3+) nanostructures were tetragonal with space group P4/nmm. Scanning electron microscope analysis and histograms revealed that diameters LaOCl:Eu super(3+) nanofibers and nanotubes, and the width of LaOCl:Eu super(3+) nanobelts were respectively 198.64 plus or minus 15.07, 168.86 plus or minus 24.70 and 2.103 plus or minus 0.3345 mu m under the 95 % confidence level. Transmission electron microscope observation showed that as-obtained LaOCl:Eu super(3+) nanotubes were hollow-centered structure. Photoluminescence (PL) analysis manifested that the LaOCl:Eu super(3+) with different morphologies emitted the predominant emission peaks at 616 and 618 nm originating from the transition super(5)D sub(0) arrow right super(7)F sub(2) of Eu super(3+) ions under the excitation of 283-nm ultraviolet light. It was found that the optimum molar ratio of Eu super(3+)/(La super(3+)+Eu super(3+)) ions was 5 %. LaOCl:Eu super(3+) nanobelts exhibited the strongest PL intensity of the three morphologies under the same doping concentration. CIE analysis demonstrated that color-tuned luminescence can be obtained by changing doping concentration of Eu super(3+) ions and morphologies of nanomaterials, which could be applied in the fields of optical telecommunication and optoelectronic devices. The possible formation mechanisms of LaOCl:Eu super(3+) nanofibers, nanobelts and nanotubes were also proposed.
•The chlorination agents and the separation of metal chlorides were summarized.•The chlorination metallurgy mechanisms were introduced in detail.•The application of chlorination metallurgy was ...introduced.•The thermodynamic feasibility of treating ores by chlorination metallurgy was also analyzed.
As a very effective metallurgical method for processing complex metal minerals, Chlorination metallurgy has been widely used in the metallurgical industry. In this paper, the chlorination agents used in the process of chlorination metallurgy were summarized as gaseous chlorination agents and solid chlorination agents. the advantages and disadvantages of each of them were compared and analyzed, and the main mechanisms involved in the process of chlorination roasting and chloride separation were discussed and analyzed, respectively; The research results of related scholars on chlorination metallurgy were summarized, and the application progress on sulfide ores, oxidized ores, wolframite concentrates and rare earth ores was introduced in detail, and from the perspective of thermodynamics, the feasibility of treating complex metal ores with chlorination metallurgy was analyzed, in order to provide some help and reference for the subsequent research and application of chlorination metallurgy.
In this study, the mechanism of chlorinated by‐products (CBPs) formation and transformation during urine electrolysis was comparatively investigated with active and nonactive electrodes. It was found ...that nutrients removal and CBPs formation was dominated by the chlorine evolution on the active Ti/RuOx‐IrOx electrodes. CBPs formation was inhibited by the ammonia and urea chlorination and kept at a relatively low level before chlorination breakpoint. After the concentration of organic CBPs (OCBPs) increasingly reaching the maximum as a result of the peak concentration of free chlorine, most free chlorine transformed into inorganic chlorination by‐products (ICBPs) with the chlorate as the main species. In contrast, the formation of CBPs on boron‐doped diamond (BDD) electrodes was jointly dominated by the direct oxidation and chlorine mediated oxidation, which resulted in the complete degradation of OCBPs and the accumulation of ICBPs throughout the electrolysis. The organics with high molecular weight readily formed CBPs. Moreover, higher current density would accelerate the production of ICBPs on both electrodes, although it could mitigate OCBPs production at chlorination breakpoint for Ti/RuOx‐IrOx anodes. Separation of chloride ions and organics with high molecular weight from urine using nanofiltration was proposed to mitigate the production of CBPs.
Concerns have been raised regarding the potential negative effects on human health of water disinfectants used in swimming pools. Among the disinfection options, the approaches using chlorine‐based ...products have been typically preferred. Chlorine readily reacts with natural organic matter that are introduced in the water mainly through the bathers, leading to the formation of potentially harmful chlorination by‐products (CBPs). The formation of CBPs is of particular concern since some have been epidemiologically associated with the development of various clinical manifestations. The higher the concentration of volatile CBPs in the water, the higher their concentration in the air above the pool, and different routes of exposure to chemicals in swimming pools (water ingestion, skin absorption, and inhalation) contribute to the individual exposome. Some CBPs may affect the respiratory and skin health of those who stay indoor for long periods, such as swimming instructors, pool staff, and competitive swimmers. Whether those who use chlorinated pools as customers, particularly children, may also be affected has been a matter of debate. In this article, we discuss the current evidence regarding the health effects of both acute and chronic exposures in different populations (work‐related exposures, intensive sports, and recreational attendance) and identify the main recommendations and unmet needs for research in this area.
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The first electrochemical promoted CH bond chlorination of sulfoxonium ylides was accomplished using magnesium chloride as the chlorine source, as well as a supporting electrolyte. ...This method does not require transition metal catalysts, external oxidants, and electrolytes, providing a green and mild route for the functionalization of sulfoxonium ylides.
Disinfection processes were applied in reclaimed water plant to eliminate pathogens and control the related health risk during water reuse. However, extra problems might emerge such as the released ...free endotoxins from the ruptured cell wall of gram-negative bacteria. Endotoxins can induce lung inflammatory responses after inhalation, which has been neglected in the water quality regulation, and the removal of endotoxin was not under consideration in the process of reclamation. In the present study, two well-known disinfection processes, chlorination and combined UV/chlorine (UV/Cl2), were performed to test the removal efficiency of endotoxin activity, as well as the inflammation inducing ability. In the pure LPS solution, UV/Cl2 treatment significantly reduced both endotoxin activity and lung inflammation responses with better oxidizability of the generated hydroxyl radical. However, its performance on bacteria liquid and real secondary effluent was more complicated. The cell wall-bound LPS have lower endotoxin activities and inflammation inducing ability. Immediately after the cell wall was destroyed, the bound LPS were released to the solution to be free LPS, which dramatically increased both the endotoxin activity and inflammation inducing ability of the water. When these free endotoxins were continuously oxidized, the endotoxin activity and inflammatory response decreased again but not to the background level. Therefore, the inflammation inducing ability of reclaimed water could not be removed efficiently. These results suggest that in spite of its high oxidability, UV/Cl2 treatment is not capable of removing the endotoxin-based toxicity, and other technologies are necessary to control endotoxin levels in reclaimed water.
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•UV/Cl2 reduced more inflammation inducing ability of endotoxin than chlorination.•The aggregate size of free endotoxin reduced significantly after UV/Cl2 treatment.•Unlike chlorination, UV/Cl2 reduces endotoxin activity and toxicity simultaneously.•Insufficient oxidation might increase the toxicity of reclaimed water.•Oxidation-released free endotoxin can be regard as a new disinfection byproduct.
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•Fe-CoO/CuO with notable electrocatalytic capabilities is easily prepared.•More than 98% of nitrate was removed by Fe-CoO/CuO@CF electrode.•Nitrate was nearly entirely (99.7%) ...converted into nitrogen gas.•Fe-CoO/CuO@CF electrode exhibits remarkable reusability.
The electrocatalytic reduction of nitrate ions (NO3−) to nitrogen gas (N2) has emerged as an effective approach for mitigating nitrate pollution in water bodies. However, the development of efficient and highly selective cathode materials remains challenging. Conventional copper-based catalysts often exhibit low selectivity because they strongly adsorb oxygen. In this study, a straightforward solvothermal and pyrolysis method was used to grow iron-doped cobalt–copper oxide heterogeneous structures on copper foam surfaces (Fe–CoO/CuO@CF). Then, the effects of the applied potential, initial NO3− concentration, Cl− concentration, electrolyte pH, and different catalysts on the catalyst performance were investigated. Compared with recently reported congeners, Fe–CoO/CuO@CF is less expensive and exhibits outstanding activity for NO3− reduction. Meanwhile, under a cathode potential of − 1.31 V vs. Ag/AgCl, Fe–CoO/CuO@CF degrades 98.6 % of NO3− in 200 min. In addition, when employing a method inspired by NH4+ removal by breakpoint chlorination, N2 selectivity over Fe–CoO/CuO@CF was raised from 10 % without Cl− to 99.7 % when supplemented with Cl−. The catalyst demonstrated excellent cyclic stability, maintaining a high electrocatalytic activity for the conversion of NO3− to N2 gas over eleven cycles. Moreover, Fe–CoO/CuO@CF enabled 63.7 % removal of NO3− from wastewater (50 mg/L NO3−–N) prepared from natural water, with 100 % conversion to N2. Computational studies showed that iron doping decreased the free energy change of the intermediate of NO3− reduction reaction. This study provides an effective strategy for the electrochemical reduction of nitrate to nitrogen gas and offers good prospects for addressing nitrate pollution.
•Physical NW-EP and chemical Cl2 were compared to remove culturable and viable cells.•NW-EP had ∼3–5 times lower energy consumption for culturable cell removal than Cl2.•NW-EP inhibited the formation ...of VBNC cells via destroying cell wall and membrane.•Osmotic pressure caused gradual inactivation of VBNC cells with cell wall damage.•NW-EP showed excellent adaptability to control VBNC cells in DI, tap and lake waters.
The induction of viable but nonculturable (VBNC) bacteria with cellular integrity and low metabolic activity by chemical disinfection causes a significant underestimation of potential microbiological risks in drinking water. Herein, a physical Co3O4 nanowire-assisted electroporation (NW-EP) was developed to induce cell damage via the locally enhanced electric field over nanowire tips, potentially achieving effective inhibition of VBNC cells as compared with chemical chlorination (Cl2). NW-EP enabled over 5-log removal of culturable cell for various G+/G- bacteria under voltage of 1.0 V and hydraulic retention time of 180 s, and with ∼3–6 times lower energy consumption than Cl2. NW-EP also achieved much higher removals (∼84.6 % and 89.5 %) of viable Bacillus cereus (G+) and Acinetobacter schindleri (G-) via generating unrecoverable pores on cell wall and reversible/irreversible pores on cell membrane than Cl2 (∼28.6 % and 41.1 %) with insignificant cell damage. The residual VBNC bacteria with cell wall damage and membrane pore resealing exhibited gradual inactivation by osmotic stress, leading to ∼99.8 % cell inactivation after 24 h storage (∼59.4 % for Cl2). Characterizations of cell membrane integrity and cell morphology revealed that osmotic stress promoted cell membrane damage for the gradual inactivation of VBNC cells during storage. The excellent adaptability of NW-EP for controlling VBNC cells in DI, tap and lake waters suggested its promising application potentials for drinking water, such as design of an external device on household taps.
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Amino acids (AAs) account for about 15–35% of dissolved organic nitrogen (DON), and are known as the important precursors of nitrogenous disinfection by-products (N-DBPs). Determining the formation ...potential (FP) of AAs to DBPs is used to reveal the key precursors of DBPs for further control, while the ideal method for N-DBPs FP of AAs during chlorination is not revealed. In this study, the ideal FP test models for five classes of priority DBPs during chlorination of four representative AAs (accounted for about 35% of total AAs) were analyzed. For haloaldehydes (HALs), haloketones (HKs), haloacetonitriles (HANs), haloacetamides (HAMs), and halonitromethanes (HNMs), their FPs during chlorination of four AAs were 0.1–13.0, 0.01–1.1, 0.1–104, not detectable (nd)-173, and nd-0.4 μg/mg, respectively. The FPs of priority DBPs had significant deviations between different FP test models and different tested AAs. For HALs, the model, whose chlorine dosage was determined by 15 × molar concentration of AAs Cl (mM) = 15 × M(named: model II), was the ideal model. For HKs, model II was also the ideal FP test model for AAs with ≤3 carbons, while for AAs with 4 carbons, the model, whose chlorine dosage was determined by keeping the residual chlorine at 1 ± 0.2 mg/L after 24 h of reaction (named: model 4), was the ideal model. For HANs and HNMs, model 4 was the ideal FP test model for most of the studied AAs. The performance of HAMs during chlorination of amino acids was totally different from other P-DBPs, and model 3 was recommended to be the ideal model, in which chlorine dosage was determined by 3 × mass concentration of AAs Cl (mg/L) = X × DOC. This study is a reference that helps researchers select an ideal model for N-DBPs FP study of AAs.
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•The ideal FP test models for AAs during chlorination were analyzed.•For P-DBPs, their FPs for four AAs ranged from 0 to 173 μg/mg.•P-DBP FPs had significant deviations between different FP test models.•This study helps researchers to select a ideal model for FP study of AAs.
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