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As bis(4-hydroxyphenyl)methanone (BHP) is one of the most common UV light stabilizers (UVLS), but exhibits endocrine disrupting toxicity, this study aims to develop useful sulfate radical-based techniques to eliminate BHP from water by activating peroxymonosulfate (PMS). Hence, while cobalt (Co) exhibits efficacy as a transition metal for the activation of PMS, the utilization of manganese/cobalt (Mn/Co) bimetallic oxides presents an even more encouraging prospect as heterogeneous catalysts for PMS activation. In this study, we have successfully produced N-doped carbon-supported Mn/Co nanoparticles (NCMC) with a distinctive hollow-engineered nanostructure. The synthesis involved the utilization of Co-MOF as a precursor, followed by easy etching and Mn doping to achieve the desired composition of Mn/Co bimetallic oxide nanoparticles. The inclusion of Mn dopant facilitates the integration of Mn/Co nanoparticles into the hollow-structured N-doped carbon matrix. NCMC demonstrates much higher activity compared to NCC and the benchmark catalyst, Co3O4 NP, in terms of PMS activation for the degradation of BHP. The findings of the eco-toxicity study indicate that the degradation of BHP by NCMC + PMS does not yield hazardous or extremely toxic byproducts, so establishing NCMC as a potentially effective heterogeneous catalyst for activating PMS in the degradation of BHP. [ABSTRACT FROM AUTHOR]

As the widely used ultraviolet (UV) filter, Ensulizole (ELZ), has been proven as an environmental hormone, development of useful techniques for eliminating ELZ is imperative. Since SO4·−-based oxidation technologies are promising for treating emerging contaminants, and cobalt (Co) appears to be an extremely useful catalyst for monopersulfate (MPS) activation, that would be critical to construct advantageous cobaltic catalyst of MPS activation. A unique activator would be derived from a special metal organic framework ([Co]pyrazine[Ni(CN)4]) which is carbonized to become a nanocluster comprised of CoNi alloy nanoparticles (NPs) confined in carbon nanospheres, and nanotubes, forming CoNi@Carbon (CNC). Such a CNC nanocomposite would exhibit several promising properties: (1) as Co is the extremely effective metal for MPS activation, CoNi is expected for offering superior performance for activating MPS; (2) high magnetization of CoNi alloy would equip CNC with a magnetically-controllability; (3) CoNi encapsulated in carbon is guarded to enhance its reusability; (4) the interlaced configurations of CNC also make it to show higher active sites for MPS activation. Thus, CNC exhibits a significantly stronger activating capability than Co3O4, which is the conventional heterogeneous catalyst for MPS. CNC/MPS also displays a lower activation energy (Ea) for ELZ degradation than literatures, showing advantages of CNC. Mechanisms for MPS activation and ELZ degradation were also elucidated to further understand elimination process of ELZ by MOF-derived cobaltic catalysts. [ABSTRACT FROM AUTHOR]

The adsorption mechanism of S-Metolachlor in an aqueous solution by sawdust biochar derived from Acacia auriculiformis (SAB) was studied. SAB was manufactured at 500 °C for 4 h under oxygen-limited conditions and characterized for SEM, EDS, pHpzc, BET, and FTIR. The adsorption kinetics, isotherm, and diffusion studies of S-Metolachlor and SAB were further explored. Moreover, the effects of the solution pH were examined on the adsorption of S-Metolachlor by SAB. The BET analysis of SAB was achieved at 106.74 m2.g−1 and the solution pH did not significantly influence the S-Metolachlor adsorption. The adsorption data were fitted into a Langmuir isotherm and the PSO model. The film diffusion coefficient Df (4.93 × 10−11 to 8.17 × 10−11 m2.s−1) and the particle diffusion coefficient Dp (1.68 × 10−11 to 2.65 × 10−11 m2.s−1) were determined and the rate-limiting step of S-Metolachlor adsorption and SAB was governed by liquid film diffusion. The S-Metolachlor adsorption process onto SAB was controlled by multiple mechanisms, including pore filling, H-bonding, hydrophobic interaction, and π-π EDA interactions. H-bonding is the main interaction for the adsorption of S-Metolachlor and SAB. Conclusively, the study illustrates that biochar produced from Acacia auriculiformis sawdust possessed effective adsorption properties for S-Metolachlor herbicide. [ABSTRACT FROM AUTHOR]

As disinfection is employed extensively, disinfection by-product bromate has become an emerging environmental issue due to its carcinogenic toxicity. For developing an effective alternative approach for reducing bromate, cobalt and nickel-based Prussian Blue (PB) analogues are proposed here for incorporating a convenient reducing agent, NaBH4 (i.e., a H2-rich reagent) for reducing bromate to bromide as cobalt and nickel are recognized as effective metals for catalyzing hydrolysis of NaBH4, and PB exhibits versatile catalytic activity. While CoPB and NiPB are comprised of the same crystalline structure, CoPB exhibits slightly higher specific surface area, more reductive surface, and more superior electron transfer than NiPB, enabling CoPB to accelerate bromate reduction. CoPB also exhibits a higher affinity towards NaBH4 than NiPB based on density functional theory calculations. Moreover, CoPB also exhibits a relatively low activation energy (i.e., 59.5 kJ/mol) of bromate reduction than NiPB (i.e., 63.2 kJ/mol). Furthermore, bromate reduction by CoPB and NiPB could be also considerably enhanced under acidic conditions, and CoPB and NiPB could still effectively remove bromate even in the presence of nitrate, sulfate and phosphate. CoPB and NiPB are also validated to be recyclable for reducing bromate, indicating that CoPB and NiPB are promising heterogeneous catalysts for reducing bromate. [ABSTRACT FROM AUTHOR]

As heterogeneous catalysis is a practical method for activating Oxone, the immobilization of transition metals (e.g., Co, Fe) on carbonaceous supports is a promising platform. Thus, this study attempts to develop a carbon-supported metallic catalyst by growing Co/Fe on carbon foam (CF) via adopting melamine foam as a readily available template which could be transferred to nitrogen-doped CF with marcoporous structures. Specifically, a unique adornment of Co/Fe species on this CF is facilely fabricated through a complexation of Co/Fe with a plant extract, tannic acid, on melamine foam, followed by carbonization to produce nano-needle-like Co/Fe on N-doped CF, forming a magnetic CF (MCF). This resultant MCF exhibits a much higher surface area of 54.6 m2/g than CF (9.5 m2/g), and possesses a much larger specific capacitance of 9.7 F/g, than that of CF as 4.0 F/g. These superior features of MCF enable it to accelerate Oxone activation in order to degrade an emerging contaminant, bis(4-hydroxyphenyl)methanone (BHPM). Furthermore, MCF + Oxone exhibits a lower activation energy as 18.6 kJ/mol for BHPM elimination and retains its effectiveness in eliminating BHPM over multiple rounds. More importantly, the CF is also prepared and directly compared with the MCF to study the composition-structure-property relationship to provide valuable insights for further understanding of catalytic behaviors, surficial characteristics, and application of such a functional carbon material. [ABSTRACT FROM AUTHOR]

Azorubin S (ARS) represents one of the most common and frequently-utilized toxic azo dyes produced from industrial activities. While various conventional treatment techniques could not effectively eliminate ARS from water, heterogeneous metal-based catalyst coupled with monopersulfate (MPS) is a highly-efficient process for eliminating ARS, in which tricobalt tetroxide (Co3O4) has been attracted increasing attention as a preeminent MPS activator due to its outstanding physicochemical properties. However, the nanoscale Co3O4 particles usually pose a limitation of serious agglomeration in the aqueous environment, thus lowering their efficiency. Thus, developing an easy-synthesized and exceptionally efficient Co3O4-based catalyst is crucially paramount. Therefore, in this work, a special hollow-structured oval-like cobalt oxide (abbreviated as HOCO) was successfully constructed using Co-metal organic framework as a precursor, which was then utilized for catalyzing activation of MPS to degrade ARS. This as-obtained HOCO exhibited distinct physicochemical characteristics from commercially-available Co3O4, which subsequently resulted in superior activities for MPS activation in ARS degradation. Specifically, 100% of ARS could be degraded in 30 min with a corresponding reaction kinetic of 0.22 min− 1 by HOCO + MPS system. SO4•– radicals were validated to be primary reactive species for ARS degradation while the degradation pathway of ARS was also elucidated. This study further provides insightful information about the development of novel hollow-structured Co3O4-based catalyst for catalyzing activation of MPS to remove toxic dyes from water. [ABSTRACT FROM AUTHOR]

Drought is one of the costliest natural disasters, effecting many aspects of human livelihoods. This study assessed drought conditions in Cambodia from Moderate Resolution Imaging Spectroradiometer (MODIS) data during 2000 to 2019 using the Vegetation Health Index. The results verified with the satellite soil moisture indicated close agreement between these two datasets. The drought areas were concentrated in the country's central plains, with the larger drought area particularly observed for 2016. Roughly 31.3% of rice-growing area was affected by severe drought during the dry season in this abnormal year (2016), compared to that of 26.1% in a normal year (2017). The results of drought probability calculated for the entire study period indicated that 63 and 17 districts were associated with droughts in the dry and wet seasons, respectively. This study demonstrated the potential application of MODIS data for decadal drought assessment over rice cultivated areas, which was important for crop and water management. [ABSTRACT FROM AUTHOR]

For developing more effective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF), a Cu-based metal organic framework, HKUST-1, is proposed to incorporate with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) under microwave (MW) for enhancing HMF oxidation to DFF. In comparison to oxidation of HMF by a conventional heating (CH), MW is validated to shorten reaction time (< 1 h) and enhance HMF conversion (> 99%) and yield of DFF (> 99%). HKUST-1 is reusable for HMF conversion using MW over multiple cycles. These results indicate that HKUST-1 is a highly effective catalyst for HMF conversion, and MW further enhances HMF conversion and increases yield of DFF significantly. [ABSTRACT FROM AUTHOR]

Rousseau was a great thinker of educational philosophy. This paper explores Rousseau's view of educational philosophy to be aware of educational goals and innovation using dialectical materialism. Methodology is a comprehensive principle, a development principle, and a specific historical focus. The above method is the basis for understanding people and human nature in general. The article indicates that education needs to understand educators as well as learners. The paper also describes the task of education to recognize that human nature is a process from childhood to adulthood. In addition, the report uses analytical and aggregated methods to realize that Rousseau's educational ideas have tremendous and profound implications for Vietnam's educational innovation today. [ABSTRACT FROM AUTHOR]

There was an investigation into the removal of 6 types of antibiotics from hospital wastewater through membrane bioreactor (MBR) treatment and ozonation processes. Six types of antibiotics, namely, Sulfamethoxazole (SMZ), Norfloxacin (NOR), Ciprofloxacin (CIP), Ofloxacin (OFL), Erythromycin (ERY), and Vancomycin (VAN) which had high detection frequencies in collected samples from hospital wastewater treatment plant (HWTPs). After MBR treatment, the removal efficiencies of SMZ, NOR, OFL, and ERY were 45%, 25%, 30%, and 16%, respectively. Among of them, almost no elimination was observed for CIP and VAN since their concentrations increased by 0.24 ± 0.18 (μg·l-1) and 0.83 ± 0.20 (μg·l-1), respectively. Then, residues of the antibiotics were removed from the MBR effluent by the ozonation process. The overall removal efficiencies of SMZ, NOR, CIP, OFL, ERY, and VAN were approximately 66 %, 88 %, 83 %, 80 %, 93 %, and 92 %, respectively. The reason might be depended on different ozone consumption of those antibiotics (ABS) in a range of 313 to 1681 μg ABS·gO--1. Consequently, the ozonation process performed better in the antibiotics removal (e.g. CIP and VAN) so ozonation could be considered as important support for the MBR treatment to reduce the risk of antibiotic residues. [ABSTRACT FROM AUTHOR]

This study evaluated nutrients removal from domestic wastewater by five plants in wetland roof systems (WR). The study plants includeArachis duranensis(1),Evolvulus alsinoides(2),Cosmos Bipinnuatus(3),Cyperus alternifoliusLinn (4), andPhilodendron hastatum(5). The WRs were acclimatized at hydraulic loading rates (HLR) of 220 m3/ha d and operated at HLR of 300 m3/ha d. The plants (1), (2), (4), and (5) had the ability to grow under the rooftop conditions with domestic wastewater as a nutrient source while the plant (3) was not suitable and dead after 20 d of operation. Generally,A. duranensis(1) andC. alternifoliusLinn (4) were the most suitable plants treating domestic wastewater under the conditions of WR. The average phosphorus removal efficiencies of (1) and (4) were approximately 75 and 89%, respectively, while the average nitrogen removal efficiencies were 69 and 92%. The phosphorus accumulation in plants (1) and (4) during operation was 20.4 and 29.4%, respectively, while the nitrogen accumulation was 21.5 and 93%. It is concluded thatC. alternifoliusLinn (4) has best nutrient removal among the study plants under the conditions of shallow bed WR treating domestic wastewater (24 ± 4 and 2.0 ± 0.4 kg TP/ha d). [ABSTRACT FROM PUBLISHER]

Mangrove forests provide important ecosystem goods and services for human society. Extensive coastal development in many developing countries has converted mangrove forests to other land uses without regard to their ecosystem service values; thus, the ecosystem state of mangrove forests is critical for officials to evaluate sustainable coastal management strategies. The objective of this study is to investigate the multidecadal change in mangrove forests in Ca Mau peninsula, South Vietnam, based on Landsat data from 1979 to 2013. The data were processed through four main steps: 1) data preprocessing; 2) image processing using the object-based image analysis (OBIA); 3) accuracy assessment; and 4) multitemporal change detection and spatial analysis of mangrove forests. The classification maps compared with the ground reference data showed the satisfactory agreement with the overall accuracy higher than 82%. From 1979 to 2013, the area of mangrove forests in the study region had decreased by 74%, mainly due to the boom of local aquaculture industry in the study region. Given that mangrove reforestation and afforestation only contributed about 13.2% during the last three decades, advanced mangrove management strategies are in an acute need for promoting environmental sustainability in the future. [ABSTRACT FROM PUBLISHER]

This is the first study on application of a sponge-membrane bioreactor (sponge MBR) for recirculation of aquaculture wastewater in the Mekong delta, Vietnam. Performance of a sponge MBR with a moving-cube sponge medium (20% v/v) was evaluated at different hydraulic retention times (HRTs) for the specific example of catfish pond wastewater. The sponge MBR was operated at HRT values of 8, 4, and 2 h, which correspond to membrane fluxes of 5, 10, and 20 L/m2 per hour, respectively. The average chemical oxygen demand (COD) removal efficiencies were maintained at 93%, 94%, and 87% at an HRT of 8, 4, and 2 h, respectively, while the average total nitrogen (TN) removal efficiencies were 84%, 70%, and 57%. The COD and TN removal efficiencies decreased with a decrease in HRT (increase in membrane flux). Permeate concentrations of COD and TN were as low as 6.3 and 2.7 mg/L at the operated HRTs, respectively. Compared to the conventional MBR, the sponge MBR had twice the TN removal capacity at the same HRT due to simultaneous nitrification-denitrification. In addition, results implicated that the fouling rate (dTMP/dt) increased in an inverse proportion with HRT (h) according to the power equation (fouling rate=4.2474 HRT−2.225). Free movement of sponges in the reactor improved fouling due to sweeping of the cake layer on the membrane surface. Results reveal that the sponge MBR was effective in terms of simultaneous organic and nitrogen removal, fouling control, and water recirculation. [ABSTRACT FROM AUTHOR]

The human pathogen Legionella pneumophila delivers a large array of the effector proteins into host cells using the Dot/Icm type IVB secretion system. Among the proteins composing the Dot/Icm system, an inner membrane protein DotI is known to be crucial for the secretion function but its structure and role in type IV secretion had not been elucidated. We report here the crystal structures of the periplasmic domains of DotI and its ortholog in the conjugation system of plasmid R64, TraM. These structures reveal a striking similarity to VirB8, a component of type IVA secretion systems, suggesting that DotI/TraM is the type IVB counterpart of VirB8. We further show that DotI and its partial paralog DotJ form a stable heterocomplex. R64 TraM, encoded by the conjugative plasmid lacking DotJ ortholog, forms a homo-hexamer. The DotI-DotJ complex is distinct from the core complex, which spans both inner and outer membranes to form a substrate conduit, and seems not to stably associate with the core complex. These results give insight into VirB8-family inner membrane proteins essential for type IV secretion and aid towards understanding the molecular basis of secretion systems essential for bacterial pathogenesis. [ABSTRACT FROM AUTHOR]