Morphology-dependent MoO3/Ni-F nanostructures with enhanced electrochemical hydrogen peroxide detection.

The present report investigates the various MoO3 morphologies prepared via different approaches such as morphologies are cubic sheet, ribbon, and hexagonal sheet. These prepared nanostructures are modified as a MoO3/Ni-F electrode used to detect hydrogen peroxide (H2O2). The influence of the morphology on the microstructural, morphological, electronic state, optical and electrochemical properties of MoO3 nanostructures are systematically studied. The recorded XRD spectra confirmed that the good crystalline nature with the orthorhombic crystal structure. The FESEM analysis shows that preparation approaches strongly influenced the MoO3 morphology. The elemental mapping and XPS analysis confirm the formation of MoO3. The obtained optical band gap values show that the MoO3 morphology-based bandgap values are 3.38, 3.17, and 2.94 eV. The modified MoO3/Ni-F electrode electrochemical impedance spectra show the CP-MoO3 has good conductivity. Moreover, the CP-MoO3/Ni-F electrode has a wide detection window, long-term stability, reproducibility, and a low detection limit is 1.2 µM. Hence, the CP-MoO3/Ni-F electrode electrochemical results suggest that the modified electrode has offered a good matrix for toxic contaminants sensing applications.

The study on lead desorption from the real-field contaminated soil by circulation-enhanced electrokinetics (CEEK) with EDTA.

This study applied a circulation-enhanced electrokinetics (CEEK) technique to remove heavy metal lead from the agricultural land. Soil samples (lead concentration around 4000 mg/kg) were collected in a certain polluted agricultural site in Nantou, Taiwan. Operational parameters of CEEK such as the voltage gradient (1.0 V/cm), the concentration of working solution (EDTA), and pH buffer (0.01 M Na2CO3) were controlled. The CEEK with EDTA can maintain at relatively neutral pH to beneficially remove heavy metals due to appropriate EO flow, electromigration, and EDTA complexation. EDTA served as the chelating agent to react with lead in soils and its concentration plays the key factor for desorbing heavy metals from soils; the 0.1 M EDTA can achieve 79% of Pb depletion (from 3703 mg/kg to 781 mg/kg). The stoichiometric calculation can be roughly used to estimate the Pb removal efficiency based on the 1:1 M ratio of Pb to EDTA and ignores other reactions between EDTA and soil constituents. The CEEK technique with 0.1 M EDTA can remove 63% Pb (from 3430 mg/kg to 1260 mg/kg) within 6-day treatment.

The lead contaminated land treated by the circulation-enhanced electrokinetics and phytoremediation in field scale.

Some agricultural lands have been contaminated by heavy metals in Taiwan for several decades, because the irrigation system was polluted by wastewater. In this study, a circulation-enhanced electrokinetics (CEEK) and phytoremediation were applied alternately to the real lead-contaminated site. In the beginning, the CEEK was used; then, the corn plants were raised. After this phytoremediation, the CEEK was employed again. Experimental results show that the lead concentration can be reduced from 5672 mg/kg to 2083 mg/kg (around 63%) after the three-stage treatment (CEEK + corn + CEEK). At each stage, CEEK, corn plants, and CEEK can remove around 25%, 5%, and 30% lead from the soil, respectively. During the whole process, the soil pH can maintain around neutral range and the electrical conductivity of soil was stable. The electricity consumption of the CEEK was quite low (89 USD per ton) and the corn plants still were alive throughout the remediation.

A specific configuration of circulation-enhanced electrokinetics (CEEK) to remediate real-site Cd and Pb contaminated soils.

This study applied circulation-enhanced electrokinetics (CEEK) technique to remove Cd and Pb from the real-site contaminated soils. Soil samples were collected in certain polluted agricultural land in Yunlin, Taiwan. The CEEK system mainly composed of a reactor fulfilling soil samples, one pair of electrodes, a circulation system of working solution and DC power supply. Results demonstrate that the real-site Cd and Pb contaminated soils can be effectively treated by the CEEK technique; the removal efficiency of Cd and Pb can reach 91% and 85%, respectively. The CEEK system can maintain relatively neutral pH of treated soils. The bonding patterns of heavy metals and H+ produced on the anode play the critical roles for removal efficiency. The recovery efficiency of Cd and Pb in the CEEK system can reach 85% and 70%; the species of recovered heavy metals is Cd(OH)2 and Pb5O8, respectively.

Electrocatalytic characterization and dye degradation of nano-TiO2 electrode films fabricated by CVD.

A 20-40 nm anatase-titania film on a titanium electrode was fabricated using chemical vapor deposition (CVD). The film was characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and atomic force microscopy (AFM). The CVD deposition time and number of deposition coatings were evaluated to establish the appropriate film fabrication parameters. Results indicate that two coatings at a deposition time of 6h each produced the best nano-TiO(2) electrode films (NTEFs) with an even distribution of ca. 20 nm diameter nanoparticles in the anatase lattice. The NTEF was tested as an electrocatalytic anode to investigate the degradation efficiency in treating methyl orange dye wastewater. A high removal efficiency of methyl orange dye and total organic carbon (TOC) of 97 and 56%, respectively; was achieved using a current density of 20 mA cm(-2) for 160 min. Cyclic voltammetry showed that the electrochemical degradation reaction rate at the NTEF surface was predominately driven by molecular diffusion. The electrocatalytic decomposition rate of organic pollutants at the NTEF is controlled by mass transport, which was associated with the nanostructure of the electrocatalytic electrode.

[African origin of Chinese domestic donkeys].

Analysis of the 367 mtDNA D-loop sequences (of which 241 sequences were collected from literature) of 399 bp in 13 Chinese domestic donkey breeds revealed 96 different haplotypes with 57 polymorphic sites. The haplotype diversity and the nucleotide diversity were 0.767-0.967 and 0.014-0.032, respectively, indicating abundant genetic diversity in Chinese domestic donkeys. The Neighbor-joining tree of Chinese domestic donkey sequences was constructed with 3 Nubian wild ass sequences, 3 Somali wild ass sequences and 6 Asian wild ass sequences. Our results suggest that the maternal ancestor of Chinese domestic donkeys is highly likely to be Somali and Nubian of African wild ass instead of Asian wild ass.