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A single-pass-mode capacitive deionization (CDI) reactor was used to remove arsenic from groundwater in the presence of multiple ions. The CDI reactor involved an applied voltage of 1.2 V and six cell pairs of activated carbon electrodes, each of which was 20 × 30 cm 2 . The results indicate that this method achieved an effluent arsenic concentration of 0.03 mg L −1 , which is lower than the arsenic concentration standard for drinking water and irrigation sources in Taiwan, during the charging stage. Additionally, the ability of the CDI to remove other coexisting ions was studied. The presence of other ions has a significant influence on the removal of arsenic from groundwater. From the analysis of the electrosorption selectivity, the preference for anion removal could be ordered as follows: NO 3 − > SO 4 2− > F − > Cl − >As. The electrosorption selectivity for cations could be ordered as follows: Ca 2+ > Mg 2+ > Na + ∼ K + . Moreover, monovalent cations can be replaced by divalent cations at the electrode surface in the later period of the electrosorption stage. Consequently, activated carbon-based capacitive deionization is demonstrated to be a high-potential technology for remediation of arsenic-contaminated groundwater. [ABSTRACT FROM AUTHOR]

This study presents a proof-of-concept data reduction and analysis protocol that can be applied to the study of polluted sediments. Sediment cores from the Nankan River estuary are used as an example of how the protocol can be employed to quantify temporal heavy metal variability. The measurement protocol produces more detailed elemental profiles than conventional techniques using a combination of data transformation techniques and multivariate analysis. Conventional sediment analyses are used to confirm the robustness of the protocol by comparisons of heavy metal concentrations. X-ray fluorescence (XRF) core scanning provides rapid, high-resolution elemental profiles from sediment cores. The technique relies on a variety of calibration methods (ratio, additive and centred log-ratio) to transform the raw data and reduce bias caused by matrix and closed-sum effects. We further test all these calibration approaches since the transformation process is an essential step for the follow up multivariate analyses. The combination of principal component and cluster analysis objectively assesses the information implicit in the dataset. The settings in each procedure are optimized to account for the variance of the dataset. This optimization protocol explains the heavy metal trends using the sediment characteristics of the cores. Heavy metal pollution is characterized by three periods and classified by their oxidation states. We show that heavy metals have an affinity with fine-grained sediments and Mn. The interpretation is confirmed by grain size analysis and inductively coupled plasma optical emission spectrometry (ICP-OES) measurements. This study provides an impartial, cost- and time-effective protocol suitable for the analysis of other heavy metal polluted sites and further studies using sediment cores as archives. [ABSTRACT FROM AUTHOR]

Hollow core-shell mesoporous TiO 2 microspheres were synthesized by a template-free solvothermal route for efficient photocatalytic degradation of acetaminophen. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Barrett–Joyner–Halenda data revealed a micrometer-sized mesoporous anatase TiO 2 hollow sphere with large surface area and efficient light harvesting. For the photocatalytic degradation of acetaminophen in 60 min, the conversion fraction of the drug increased from 88% over commercial Degussa P25 TiO 2 to 94% over hollow spheres with about 25% increase in the initial reaction rate. Even after 10 repeated runs, the recycled hollow spheres showed good photodegradation activity. The intermediates generated in the photocatalytic reactions were eventually converted into molecules that are easier to handle. The simple fabrication route would facilitate the development of photocatalysts for the decomposition of environmental contaminants. [ABSTRACT FROM AUTHOR]

A modified successive ionic layer adsorption and reaction (SILAR) process was used for deposition of coupled CdS and CdSe quantum dots (QDs) on the surface of orientated ZnO nanorod arrays. This solution-based process provides a conformal and homogeneous QDs deposition along the ZnO nanorod arrays with no entry clogging. The prepared multi-heterojunction CdSe/CdS/ZnO nanorod-arrayed photoanodes are highly visible-light-sensitive and show improved ion diffusion and effective suppression of electron–hole pair recombination. For photoeletrochemical solar water splitting, the photoanode prepared using the modified SILAR outperformed that using the conventional SILAR by >15% improvement in solar-to-hydrogen conversion efficiency. [ABSTRACT FROM AUTHOR]

• Coexisting isolated CuO and Cu–O–Ti were synthesized via one-step AASA. • Long-term stability (250 °C, 200 h) on CO oxidation mineralization. • Estimated temperature-dependence TOF summarized the effects of active sites. • Isolated CuO contributed to the initiation of the reaction at about 50 °C. • CO oxidation was dominated by the interfacial site of Cu–O–Ti. Although the low-temperature reaction mechanism of catalytic CO oxidation reaction remains unclear, the active sites of copper play a crucial role in this mechanism. One-step aerosol-assisted self-assembly (AASA) process has been developed for the synthesis of mesoporous Cu-doped TiO 2 microspheres (CuTMS) to incorporate copper into the TiO 2 lattice. This strategy highly enhanced the dispersion of copper from 41.10 to 83.65%. Long-term stability of the as-synthesized CuTMS materials for catalytic CO oxidation reaction was monitored using real-time mass spectrum. Isolated CuO and Cu-O-Ti were formed as determined by X-ray photoelectron spectroscopy (XPS). The formation of the Cu-O-Ti bonds in the crystal lattice changes the electron densities of Ti(IV) and O, causing a subsequent change in Ti(III)/Ti(IV) and O non /O Total ratio. 20CuTMS contained the highest lattice distortion (0.44) in which the O non /O Total ratio is lowest (0.18). This finding may be attributed to the absolute formation of the Cu-O-Ti bonds in the crystal lattice. However, the decrease of Ti(III)/Ti(IV) ratio to about 0.35 of 25CuTMS was caused by the CuO cluster formation on the surface. N 2 O titration-assisted H 2 temperature-programmed reduction and in-situ Fourier transform infrared spectroscopy revealed the properties of copper and effects of active sites. [ABSTRACT FROM AUTHOR]