Locally enhanced electric field treatment (LEEFT) for water disinfection

• Nanowire-assisted LEEFT is applied for water disinfection with low voltages. • LEEFT inactivates bacteria by disrupting cell membrane through electroporation. • Multiple electrodes and device configurations have been developed for LEEFT. • The LEEFT is low-cost, highly efficient, and produces no DBPs. • The LEEFT can potentially be applicable for water disinfection at all scales. Water disinfection is a critical step in water and wastewater treatment. The most widely used chlorination suffers from the formation of carcinogenic disinfection by-products (DBPs) while alternative methods (e.g., UV, O₃, and membrane filtration) are limited by microbial regrowth, no residual disinfectant, and high operation cost. Here, a nanowire-enabled disinfection method, locally enhanced electric field treatment (LEEFT), is introduced with advantages of no chemical addition, no DBP formation, low energy consumption, and efficient microbial inactivation. Attributed to the lightning rod effect, the electric field near the tip area of the nanowires on the electrode is significantly enhanced to inactivate microbes, even though a small external voltage (usually<5 V) is applied. In this review, after emphasizing the significance of water disinfection, the theory of the LEEFT is explained. Subsequently, the recent development of the LEEFT technology on electrode materials and device configurations are summarized. The disinfection performance is analyzed, with respect to the operating parameters, universality against different microorganisms, electrode durability, and energy consumption. The studies on the inactivation mechanisms during the LEEFT are also reviewed. Lastly, the challenges and future research of LEEFT disinfection are discussed.     

Using mRNA to investigate the effect of low-pressure ultraviolet disinfection on the viability of E. coli

UV can induce damages on mRNA consistently among different genes. SOS response was more active after UV treatment. Programmed cell death was not found to be more active after UV treatment. The efficacy of ultraviolet (UV) disinfection has been analyzed and validated by numerous studies using culture-based methods, yet the discovery of the viable but nonculturable state necessitates the investigation of UV disinfection based on viability parameters. Paired regulators of the SOS response system, recA-lexA, and the programmed cell death system, mazEF, in Escherichia coli were chosen as the target genes, and the effect of UV irradiation on the mRNAs of the four genes was studied. This research showed that, after UV irradiation, the responses of the mRNAs were highly consistent, with reduction percentages of approximately 60% at 20 mJ/cm², 70% at 40 mJ/cm², and 90% at 80 mJ/cm², and these reductions were believed to be the result of direct UV damage to nucleic acids. After 24 h of dark incubation, recA and lexA were both upregulated but to a lesser extent for repressor lexA; and mazE and mazF were both downregulated. This result implies that UV irradiation induces the dark repair system more actively, and the cells will proceed to death at a rate similar to that associated with natural decay.     

Unlocked disinfection by-product formation potential upon exposure of swimming pool water to additional stimulants

• Swimming pool water was studied for DBPs upon exposure to additional stimulants. • DBP formation could be induced by residual chlorine and extended incubation. • Urine led to a massive formation of chloroform with additional stimulants. • Reactions between chlorine and anthropogenic organics were slow and long-lasting. • Urine control and air ventilation should be on the priority list for pool management. Anthropogenic organics are known to be responsible for the formation of harmful disinfection by-products (DBPs) in swimming pool water (SPW). The research explored an important scenario of SPW with no additional anthropogenic organic input. With stimulations by residual chlorine or additional chlorine and extended incubation, the formation of DBPs, especially chloroform, was significantly induced. Similar observations were found by investigating synthetic SPW made with sweat and urine. The presence of urine led to a massive formation of chloroform, as noted by an approximate 19-fold increase after 165-day incubation with a shock chlorine dose. The research suggests that consistent residual chlorine and long water retention as two typical features of SPW could unlock the DBP formation potential of anthropogenic organics. Thus, limiting the introduction of anthropogenic organics may not have an immediate effect on reducing DBP levels, because their reactions with chlorine can be slow and long-lasting. Pool management should prioritize on control of urine and improving air ventilation. This work is useful to deepen understandings about DBP formation in SPW and provide implications for pool management and prospective legislation.     

Co-application of energy uncoupling and ultrafiltration in sludge treatment: Evaluations of sludge reduction,supernatant recovery and membrane fouling control

• Effects of metabolic uncouplers addition on sludge reduction were carried out. • TCS addition effectively inhibited ATP synthesis and reduced sludge yield. • The effluent quality such as TOC and ammonia deteriorated but not significantly. • Suitable dosage retarded biofouling during sludge water recovery by UF membrane. Energy uncoupling is often used for sludge reduction because it is easy to operate and does not require a significant amount of extra equipments (i.e. no additional tank required). However, over time the supernatant extracted using this method can deteriorate, ultimately requiring further treatment. The purpose of this study was to determine the effect of using a low-pressure ultrafiltration membrane process for sludge water recovery after the sludge had undergone an energy uncoupling treatment (using 3,3′,4′,5-tetrachlorosalicylanilide (TCS)). Energy uncoupling was found to break apart sludge floc by reducing extracellular polymeric substances (EPS) and adenosine triphosphate (ATP) content. Analysis of supernatant indicated that when energy uncoupling and membrane filtration were co-applied and the TCS dosage was below 30 mg/L, there was no significant deterioration in organic component removal. However, ammonia and phosphate concentrations were found to increase as the concentration of TCS added increased. Additionally, due to low sludge concentrations and EPS contents, addition of 30–60 mg/L TCS during sludge reduction increased the permeate flux (two times higher than the control) and decreased the hydraulic reversible and cake layer resistances. In contrast, high dosage of TCS aggravated membrane fouling by forming compact fouling layers. In general, this study found that the co-application of energy uncoupling and membrane filtration processes represents an effective alternative method for simultaneous sludge reduction and sludge supernatant recovery.     

Composition,dispersion, and health risks of bioaerosols in wastewater treatment plants: A review

• Bioaerosols are produced in the process of wastewater biological treatment. • The concentration of bioaerosol indoor is higher than outdoor. • Bioaerosols contain large amounts of potentially pathogenic biomass and chemicals. • Inhalation is the main route of exposure of bioaerosol. • Both the workers and the surrounding residents will be affected by the bioaerosol. Bioaerosols are defined as airborne particles (0.05–100 mm in size) of biological origin. They are considered potentially harmful to human health as they can contain pathogens such as bacteria, fungi, and viruses. This review summarizes the most recent research on the health risks of bioaerosols emitted from wastewater treatment plants (WWTPs) in order to improve the control of such bioaerosols. The concentration and size distribution of WWTP bioaerosols; their major emission sources, composition, and health risks; and considerations for future research are discussed. The major themes and findings in the literature are as follows: the major emission sources of WWTP bioaerosols include screen rooms, sludge-dewatering rooms, and aeration tanks; the bioaerosol concentrations in screen and sludge-dewatering rooms are higher than those outdoors. WWTP bioaerosols contain a variety of potentially pathogenic bacteria, fungi, antibiotic resistance genes, viruses, endotoxins, and toxic metal(loid)s. These potentially pathogenic substances spread with the bioaerosols, thereby posing health risks to workers and residents in and around the WWTP. Inhalation has been identified as the main exposure route, and children are at a higher risk of this than adults. Future studies should identify emerging contaminants, establish health risk assessments, and develop prevention and control systems.     

Comparative genotoxicity of water processed by three drinking water treatment plants with different water treatment procedures

• Genotoxicity of substances is unknown in the water after treatment processes. • Genotoxicity decreased by activated carbon treatment but increased by chlorination. • Halogenated hydrocarbons and aromatic compounds contribute to genotoxicity. • Genotoxicity was assessed by umu test; acute and chronic toxicity by ECOSAR. • Inconsistent results confirmed that genotoxicity cannot be assessed by ECOSAR. Advanced water treatment is commonly used to remove micropollutants such as pesticides, endocrine disrupting chemicals, and disinfection byproducts in modern drinking water treatment plants. However, little attention has been paid to the changes in the genotoxicity of substances remaining in the water following the different water treatment processes. In this study, samples were collected from three drinking water treatment plants with different treatment processes. The treated water from each process was analyzed and compared for genotoxicity and the formation of organic compounds. The genotoxicity was evaluated by an umu test, and the acute and chronic toxicity was analyzed through Ecological Structure- Activity Relationship (ECOSAR). The results of the umu test indicated that biological activated carbon reduced the genotoxicity by 38%, 77%, and 46% in the three drinking water treatment plants, respectively, while chlorination increased the genotoxicity. Gas chromatograph-mass spectrometry analysis revealed that halogenated hydrocarbons and aromatic compounds were major contributors to genotoxicity. The results of ECOSAR were not consistent with those of the umu test. Therefore, we conclude that genotoxicity cannot be determined using ECOSAR .     

Surface modification of mesoporous silica nanoparticle with 4-triethoxysilylaniline to enhance seawater desalination properties of thin-film nanocomposite reverse osmosis membranes

• Mesoporous silica nanoparticle was modified with 4-triethoxysilylaniline. • AMSN-based TFN-RO membranes were prepared for seawater desalination. • Water transport capability of the AMSN was limited by polyamide. • Polyamide still plays a key role in permeability of the TFN RO membranes. Mesoporous silica nanoparticles (MSN), with higher water permeability than NaA zeolite, were used to fabricate thin-film nanocomposite (TFN) reverse osmosis (RO) membranes. However, only aminoalkyl-modified MSN and low-pressure (less than 2.1 MPa) RO membrane were investigated. In this study, aminophenyl-modified MSN (AMSN) were synthesized and used to fabricate high-pressure (5.52 MPa) RO membranes. With the increasing of AMSN dosage, the crosslinking degree of the aromatic polyamide decreased, while the hydrophilicity of the membranes increased. The membrane morphology was maintained to show a ridge-and-valley structure, with only a slight increase in membrane surface roughness. At the optimum conditions (AMSN dosage of 0.25 g/L), when compared with the pure polyamide RO membrane, the water flux of the TFN RO membrane (55.67 L/m²/h) was increased by about 21.6%, while NaCl rejection (98.97%) was slightly decreased by only 0.29%. However, the water flux of the membranes was much lower than expected. We considered that the enhancement of RO membrane permeability is attributed to the reduction of the effective thickness of the PA layer.     

Review on remediation technologies for arsenic-contaminated soil

• Recent progress of As-contaminated soil remediation technologies is presented. • Phytoextraction and chemical immobilization are the most widely used methods. • Novel remediation technologies for As-contaminated soil are still urgently needed. • Methods for evaluating soil remediation efficiency are lacking. • Future research directions for As-contaminated soil remediation are proposed. Arsenic (As) is a top human carcinogen widely distributed in the environment. As-contaminated soil exists worldwide and poses a threat on human health through water/food consumption, inhalation, or skin contact. More than 200 million people are exposed to excessive As concentration through direct or indirect exposure to contaminated soil. Therefore, affordable and efficient technologies that control risks caused by excess As in soil must be developed. The presently available methods can be classified as chemical, physical, and biological. Combined utilization of multiple technologies is also common to improve remediation efficiency. This review presents the research progress on different remediation technologies for As-contaminated soil. For chemical methods, common soil washing or immobilization agents were summarized. Physical technologies were mainly discussed from the field scale. Phytoextraction, the most widely used technology for As-contaminated soil in China, was the main focus for bioremediation. Method development for evaluating soil remediation efficiency was also summarized. Further research directions were proposed based on literature analysis.     

Toxic effect of sodium perfluorononyloxy-benzenesulfonate on Pseudomonas stutzeri in aerobic denitrification,cell structure and gene expression

• OBS inhibited the growth of P. stutzeri and destroyed its structure. • OBS was toxic to the aerobic denitrification process of P. stutzeri. • OBS induced the production of ROS in P. stutzeri. • OBS affected the expression of key genes involved in denitrification and SOD. The toxicities of sodium perfluorononyloxy-benzenesulfonate (OBS) to animals and plants are similar to those of perfluorooctane sulfonate. However, the mechanism of its toxicity to aerobic denitrifying bacteria is still unclear. In the present study, the ecotoxicity of OBS on an aerobic denitrifying strain, Pseudomonas stutzeri, was evaluated. The results showed that a dosage of OBS clearly affected the growth and aerobic denitrification of P. stutzeri. When compared with an unamended control, the degradation efficiency of the total nitrogen decreased by 30.13% during exposure to 200 mg/L of OBS, and the complete degradation time of nitrate-nitrogen was delayed by 4 h. The lactate dehydrogenase and superoxide dismutase produced by the bacteria increased with the concentration of OBS, and reactive oxygen species were also detected by confocal laser scanning microscope imaging. Transmission electron microscope imaging revealed chromosome deformation of the cells and damage to cell content; moreover, outer membrane vesicles were secreted from the bacteria, which was the important detoxification mechanism of P. stutzeri to OBS. Expression of the genes involved in aerobic nitrification and oxidative stress were also changed under OBS stress, which further confirmed the toxicity of OBS to P. stutzeri. This study reveals the environmental exposure risk of OBS from the perspective of microorganisms.     

Biological conversion pathways of sulfate reduction ammonium oxidation in anammox consortia

• The SRAO phenomena tended to occur only under certain conditions. • High amount of biomass and non-anaerobic condition is requirement for SRAO. • Anammox bacteria cannot oxidize ammonium with sulfate as electron acceptor. • AOB and AnAOB are mainly responsible for ammonium conversion. • Heterotrophic sulfate reduction mainly contributed to sulfate conversion. For over two decades, sulfate reduction with ammonium oxidation (SRAO) had been reported from laboratory experiments. SRAO was considered an autotrophic process mediated by anammox bacteria, in which ammonium as electron donor was oxidized by the electron acceptor sulfate. This process had been attributed to observed transformations of nitrogenous and sulfurous compounds in natural environments. Results obtained differed largely for the conversion mole ratios (ammonium/sulfate), and even the intermediate and final products of sulfate reduction. Thus, the hypothesis of biological conversion pathways of ammonium and sulfate in anammox consortia is implausible. In this study, continuous reactor experiments (with working volume of 3.8L) and batch tests were conducted under normal anaerobic (0.2≤DO<0.5 mg/L) / strict anaerobic (DO<0.2 mg/L) conditions with different biomass proportions to verify the SRAO phenomena and identify possible pathways behind substrate conversion. Key findings were that SRAO occurred only in cases of high amounts of inoculant biomass under normal anaerobic condition, while absent under strict anaerobic conditions for same anammox consortia. Mass balance and stoichiometry were checked based on experimental results and the thermodynamics proposed by previous studies were critically discussed. Thus anammox bacteria do not possess the ability to oxidize ammonium with sulfate as electron acceptor and the assumed SRAO could, in fact, be a combination of aerobic ammonium oxidation, anammox and heterotrophic sulfate reduction processes.     

Biotoxicity evaluation of zinc oxide nanoparticles on bacterial performance of activated sludge at COD,nitrogen, and phosphorus reduction

• ZnO-NP disrupted metabolic/catabolic balance of bacteria by affecting DHA activity. • ZnO-NPs toxicity was related to Zn²⁺ ion, interaction with cell and ROS generation. • Exposure to ZnO-NPs resulted in changed bacterial community structure at sludge. • The change in the EPS content was observed during exposure to ZnO-NPs. The unique properties and growing usage of zinc oxide nanoparticles increase their release in municipal wastewater treatment plants. Therefore, these nanoparticles, by interacting with microorganisms, can fail the suitable functioning of biological systems in treatment plants. For this reason, research into the toxicity of ZnO is urgent. In the present study, the toxicity mechanism of ZnO-NPs towards microbial communities central to granular activated sludge (GAS) performance was assessed over 120-day exposure. The results demonstrate that the biotoxicity of ZnO-NPs is dependent upon its dosage, exposure time, and the extent of reactive oxygen species (ROS) production. Furthermore, GAS performance and the extracellular polymeric substances (EPS) content were significantly reduced at 50 mg/L ZnO-NPs. This exposure led to decreases in the activity of ammonia monooxygenase (25.2%) and nitrate reductase (11.9%) activity. The Field emission scanning electron microscopy images confirmed that ZnO-NPs were able to disrupt the cell membrane integrity and lead to cell/bacterial death via intracellular ROS generation which was confirmed by the Confocal Laser Scanning Microscopy analysis. After exposure to the NPs, the bacterial community composition shifted to one dominated by Gram-positive bacteria. The results of this study could help to develop environmental standards and regulations for NPs applications and emissions.     

Enhanced triallyl isocyanurate (TAIC) degradation through application of an O3/UV process: Performance optimization and degradation pathways

• UV/O₃ process had higher TAIC mineralization rate than O₃ process. • Four possible degradation pathways were proposed during TAIC degradation. • pH impacted oxidation processes with pH of 9 achieving maximum efficiency. • CO₃^2– negatively impacted TAIC degradation while HCO₃^– not. • Cl^– can be radicals scavenger only at high concentration (over 500 mg/L Cl^–). Triallyl isocyanurate (TAIC, C₁₂H₁₅N₃O₃) has featured in wastewater treatment as a refractory organic compound due to the significant production capability and negative environmental impact. TAIC degradation was enhanced when an ozone(O₃)/ultraviolet(UV) process was applied compared with the application of an independent O₃ process. Although 99% of TAIC could be degraded in 5 min during both processes, the O₃/UV process had a 70%mineralization rate that was much higher than that of the independent O₃ process (9%) in 30 min. Four possible degradation pathways were proposed based on the organic compounds of intermediate products identified during TAIC degradation through the application of independent O₃ and O₃/UV processes. pH impacted both the direct and indirect oxidation processes. Acidic and alkaline conditions preferred direct and indirect reactions respectively, with a pH of 9 achieving maximum Total Organic Carbon (TOC) removal. Both CO₃^2– and HCO₃^– decreased TOC removal, however only CO₃^2– negatively impacted TAIC degradation. Effects of Cl^– as a radical scavenger became more marked only at high concentrations (over 500 mg/L Cl^–). Particulate and suspended matter could hinder the transmission of ultraviolet light and reduce the production of HO· accordingly.     

Assessment of antibiotic resistance genes in dialysis water treatment processes

• Quantitative global ARGs profile in dialysis water was investigated. • Totally 35 ARGs were found in the dialysis treatment train. • 29 ARGs (highest) were found in carbon filtration effluent. • erm and mtrD-02 occurred in the final effluent. • The effluent was associated with health risks even after RO treatment. Dialysis water is directly related to the safety of hemodialysis patients, thus its quality is generally ensured by a stepwise water purification cascade. To study the effect of water treatment on the presence of antibiotic resistance genes (ARGs) in dialysis water, this study used propidium monoazide (PMA) in conjunction with high throughput quantitative PCR to analyze the diversity and abundance of ARGs found in viable bacteria from water having undergone various water treatment processes. The results indicated the presence of 35 ARGs in the effluents from the different water treatment steps. Twenty-nine ARGs were found in viable bacteria from the effluent following carbon filtration, the highest among all of the treatment processes, and at 6.96 Log (copies/L) the absolute abundance of the cphA gene was the highest. Two resistance genes, erm (36) and mtrD-02, which belong to the resistance categories macrolides-lincosamides-streptogramin B (MLSB) and other/efflux pump, respectively, were detected in the effluent following reverse osmosis treatment. Both of these genes have demonstrated the potential for horizontal gene transfer. These results indicated that the treated effluent from reverse osmosis, the final treatment step in dialysis-water production, was associated with potential health risks.     

A review of measurement methods for peracetic acid (PAA)

• Physical and chemical properties and application of peracetic acid solution. • Determination method of high concentration peracetic acid. • Determination method of residual peracetic acid (low concentration). Peroxyacetic acid has been widely used in food, medical, and synthetic chemical fields for the past several decades. Recently, peroxyacetic acid has gradually become an effective alternative disinfectant in wastewater disinfection and has strong redox capacity for removing micro-pollutants from drinking water. However, commercial peroxyacetic acid solutions are primarily multi-component mixtures of peroxyacetic acid, acetic acid, hydrogen peroxide, and water. During the process of water treatment, peroxyacetic acid and hydrogen peroxide (H₂O₂) often coexist, which limits further investigation on the properties of peroxyacetic acid. Therefore, analytical methods need to achieve a certain level of selectivity, particularly when peroxyacetic acid and hydrogen peroxide coexist. This review summarizes the measurement and detection methods of peroxyacetic acid, comparing the principle, adaptability, and relative merits of these methods.     

Phosphorus transformation under the influence of aluminum,organic carbon,and dissolved oxygen at the water-sediment interface: A simulative study

• The three simulation factors caused various changes in both water and sediment. • Responses to simulations differed with the reported natural lakes and wetlands. • Al has dominant effects on sediment P release control among the three factors. • Adding sediment Al can be effective and safe under the simulated conditions. • Polyphosphates were not generated, while added phytate was rather stable. The effects of sediment aluminum (Al), organic carbon (OC), and dissolved oxygen (DO) on phosphorus (P) transformation, at the water-sediment interface of a eutrophic constructed lake, were investigated via a series of simulative experiments. The above three factors had various influences on dissolved P concentration, water pH, water and surface sediment appearance, and P fractions. Additions of Al had the greatest effect on suppressing P release, and the water pH remained alkaline in the water-sediment system under various OC and DO conditions. No dissolution of the added Al was detected. ³¹P-NMR characterization suggested that OC addition did not promote biological P uptake to polyphosphates under oxic conditions. The simulation result on the added phytate indicated the absence of phytate in the original lake sediment. As compared to the reported natural lakes and wetland, the water-sediment system of the constructed lake responded differently to some simulative conditions. Since Al, OC, and DO can be controlled with engineering methods, the results of this study provide insights for the practical site restorations.     

Distribution of antibiotic resistance genes and their association with bacteria and viruses in decentralized sewage treatment facilities

• Distribution of ARGs in decentralized sewage facilities were investigated. • Bacitracin-ARGs were most predominant ARGs in rural wastewater. • ARGs were identified in bacterial and viral community. • ARGs of rpoB, drfE, gyrA and parC were both correlated with bacteria and phages. • More attention should be paid to the risk of spreading ARG by phages. The distribution of antibiotic resistance genes (ARGs) has been intensively studied in large-scale wastewater treatment plants and livestock sources. However, small-scale decentralized sewage treatment facilities must also be explored due to their possible direct exposure to residents. In this study, six wastewater treatment facilities in developed rural areas in eastern China were investigated to understand their risks of spreading ARGs. Using metagenomics and network analysis tools, ARGs and bacterial and viral communities were identified in the influent (INF) and effluent (EFF) samples. The dominant ARGs belonged to the bacitracin class, which are different from most of municipal wastewater treatment plants (WWTPs). The dominant hosts of ARGs are Acidovorax in bacterial communities and Prymnesiovirus in viral communities. Furthermore, a positive relationship was found between ARGs and phages. The ARGs significantly correlated with phages were all hosted by specific genera of bacteria, indicating that phages had contributed to the ARG’s proliferation in sewage treatment facilities. Paying significant concern on the possible enhanced risks caused by bacteria, viruses and their related ARGs in decentralized sewage treatment facilities is necessary.     

Evaluation of the technoeconomic feasibility of electrochemical hydrogen peroxide production for decentralized water treatment

• Gas diffusion electrode (GDE) is a suitable setup for practical water treatment. • Electrochemical H₂O₂ production is an economically competitive technology. • High current efficiency of H₂O₂ production was obtained with GDE at 5–400 mA/cm². • GDE maintained high stability for H₂O₂ production for ~1000 h. • Electro-generation of H₂O₂ enhances ibuprofen removal in an E-peroxone process. This study evaluated the feasibility of electrochemical hydrogen peroxide (H₂O₂) production with gas diffusion electrode (GDE) for decentralized water treatment. Carbon black-polytetrafluoroethylene GDEs were prepared and tested in a continuous flow electrochemical cell for H₂O₂ production from oxygen reduction. Results showed that because of the effective oxygen transfer in GDEs, the electrode maintained high apparent current efficiencies (ACEs,>80%) for H₂O₂ production over a wide current density range of 5–400 mA/cm², and H₂O₂ production rates as high as ~202 mg/h/cm² could be obtained. Long-term stability test showed that the GDE maintained high ACEs (>85%) and low energy consumption (<10 kWh/kg H₂O₂) for H₂O₂ production for 42 d (~1000 h). However, the ACEs then decreased to ~70% in the following 4 days because water flooding of GDE pores considerably impeded oxygen transport at the late stage of the trial. Based on an electrode lifetime of 46 days, the overall cost for H₂O₂ production was estimated to be ~0.88 $/kg H₂O₂, including an electricity cost of 0.61 $/kg and an electrode capital cost of 0.27 $/kg. With a 9 cm² GDE and 40 mA/cm² current density, ~2–4 mg/L of H₂O₂ could be produced on site for the electro-peroxone treatment of a 1.2 m³/d groundwater flow, which considerably enhanced ibuprofen abatement compared with ozonation alone (~43%–59% vs. 7%). These findings suggest that electrochemical H₂O₂ production with GDEs holds great promise for the development of compact treatment technologies for decentralized water treatment at a household and community level.     

PM-support interfacial effect and oxygen mobility in Pt,Pd or Rh-loaded (Ce,Zr,La)O2 catalysts

• Pt/CZL exhibits the optimum catalytic performance for HC and NO_x elimination. • The strong PM-Ce interaction favors the oxygen mobility and DOSC. • Pd/CZL shows higher catalytic activity for CO conversion due to more O_latt species. • Great oxygen mobility at high temperature broadens the dynamic operation window. • The relationship between DOSC and catalytic performance is revealed. The physicochemical properties of Pt-, Pd- and Rh- loaded (Ce,Zr,La)O₂ (shorted for CZL) catalysts before/after aging treatment were systematically characterized by various techniques to illustrate the relationship of the dynamic oxygen storage/release capacity and redox ability with their catalytic performances for HC, NO_x and CO conversions. Pt/CZL catalyst exhibits the optimum catalytic performance for HC and NO_x elimination, which mainly contribute to its excellent redox ability and dynamic oxygen storage/release capacity (DOSC) at lower temperature due to the stronger PM (precious metals)-support interaction. However, the worse stability of Pt-O-Ce species and volatile Pt oxides easily result in the dramatical decline in catalytic activity after aging. Pd/CZL shows higher catalytic activity for CO conversion by reason of more O_latt species as the active oxygen for CO oxidation reaction. Rh/CZL catalyst displays the widest dynamic operation window for NO_x elimination as a result of greater oxygen mobility at high temperature, and the ability to retain more Rh-O-Ce species after calcined at 1100°C effectively restrains sintering of active RhO_x species, improving the thermal stability of Rh/CZL catalyst.