Mechanism and ecological environmental risk assessment of peroxymonosulfate for the treatment of heavy metals in soil.

Oxidation technologies based on peroxymonosulfate (PMS) have been effectively used for the remediation of soil organic pollutants due to their high efficiency. However, the effects of advanced PMS-based oxidation technologies on other soil pollutants, such as heavy metals, remain unknown. In this study, changes in the form of heavy metals in soil after using PMS and the risk of pollution to the ecological environment were investigated. Furthermore, two risk assessment methods, the mung bean germination toxicity test and groundwater leaching soil column test, were employed to evaluate the soil before and after PMS treatment. The results showed that PMS has a strong ability to degrade complex compounds, enabling the transformation of heavy metals, such as Cd, Pb, and Zn, from stable to active states in the soil. The risk assessments showed that PMS treatment activated heavy metals in the soil, which delayed the growth of plants, increased heavy metal content in plant tissues and the risk of groundwater pollution. These findings provide a new perspective for understanding the effects of PMS on soil, thus facilitating the sustained and reliable development of future research in the field of advanced oxidation applied to soil treatment.

The silicon active sites driven by oxygen vacancies in iron silicate for activating peroxymonosulfate.

Most metal sites and some non-metallic sites such as carbon and nitrogen are usually considered to be traditional active sites during peroxymonosulfate (PMS) activation. However, as an important non-metallic element, the actual role of silicon (Si) in PMS activation still remains unclear. In this work, taking iron silicate (FeSi) as an example, the role of the Si region in PMS activation was clearly revealed. The experiments and density functional theory (DFT) calculation results showed that besides the traditional Fe sites, the Si also played a non-negligible role during PMS activation. In FeSi containing oxygen vacancies (Ovac), Fe-Si was the active site instead of Fe-Fe. The Bard charge results implied that the presence of Ovac tuned the electronic properties of FeSi, making the Si participate in PMS activation. This work deepened understanding of the role of Si in silicates for PMS activation and provided a theoretical basis for the development of excellent Si-based catalysts.

Electrochemical degradation of refractory pollutants using TiO2 single crystals exposed by high-energy {001} facets.

Anodic material plays a vital role in electrochemical water treatment. Titanium dioxide (TiO2) has been widely recognized as an excellent semiconductor photocatalyst, rather than an efficient electrocatalyst, due to its relatively low electric conductivity and poor electrochemical activity. In this work, it is found that TiO2 can actually become a superior electrocatalyst when its crystal shape and exposed facet are finely tuned. The shape-engineered TiO2 single crystals with {001} facets exhibit an excellent electro-catalytic activity and stability for degrading typical organic pollutants such as rhodamine B and bisphenol A, and treating complex landfill leachate. Its electro-catalytic superiority is mainly attributed to the single-crystalline structure and exposed polar {001} facet. Our findings could provide new possibility of utilizing TiO2 for efficient electrochemical water treatment because of its high activity, great stability, low cost and no toxicity.

A green approach for preparing doped TiO(2) single crystals.

Doped TiO2 with metal, nonmetal, and rare earth elements has shown a great potential in energy and environmental applications, but it is difficult to dope well-defined TiO2 single crystals (SCs) with {001} exposed facet due to their high crystallinity. In this work, we developed a green and general approach to prepare the {001}-exposed TiO2 SCs doped with various elements, on the basis of recycling the wasted ethylene glycol electrolyte from the anodic oxidation for TiO2 nanotube preparation. All six representative elements (i.e., metal, nonmetal, and rare earth types) could be successfully doped into the TiO2 SCs without breaking their single-crystalline structure and exposed high-energy facet. The electronic properties of the doped TiO2 SCs were significantly improved. All the doped TiO2 SCs exhibited a superior photoactivity under visible-light irradiation for degrading rhodamine B, a typical organic pollutant. The prepared doped TiO2 SCs have a promising potential in environmental and energy applications.

Synthesis of a highly efficient BiOCl single-crystal nanodisk photocatalyst with exposing {001} facets.

BiOCl is known as a highly efficient photocatalyst for degradation of pollutants. However, effective methods for fabricating BiOCl nanomaterials with well-defined facets are still lacking. In this work, a facile synthetic method was developed for the fabrication of BiOCl nanodisks with exposed {001} facets. The central feature of this approach was the use of water as the hydrolysis agent and ethylene glycol as the crystal growth inhibitor agent to tune the growth of BiOCl nanomaterial. With this approach, the size and shape of BiOCl nanostructures could be effectively tuned through adjusting the volume ratio of ethylene glycol/H2O. In addition, the mechanism of the crystal growth in this fabrication process was elucidated. The as-prepared BiOCl nanodisks with exposed {001} facets exhibited an excellent photocatalytic activity towards Rhodamine B degradation under both ultraviolet and visible light irradiations. These findings shed light on the deep understanding of formation mechanisms of BiOCl nanodisks and provide an efficient and facile method for the synthesis of high active photocatalyst.

Hexagonal microrods of anatase tetragonal TiO2: self-directed growth and superior photocatalytic performance.

Novel TiO2 mesocrystalline microrods with unique hexagonal structure were prepared via a facial thermal method. Their photocatalytic performance under UV irradiation was much higher than that of the Degussa P25 benchmark, one of the best commercial polycrystalline TiO2 photocatalyst. The hexagonal microrods were formed through self-directed self-assembly within intermediate scaffolds.

[Effect of triptolide on sensitivity of K562/A02 cell line to adriamycin].

This study was aimed to evaluate the effect of triptolide (TPL) on the reversal of multidrug resistance in K562/A02 cell line. The sensitivity of K562 and K562/A02 to adriamycin (ADM) and reversal of drug resistance were determined with MTT method. The concentration of intracellular ADM and P-glycoprotein expression were detected by flow cytometry. Luciferase reporter gene assay was used to detect the transcriptional activity of MDR1 promoter. The results showed that TPL significantly decreased the resistance degree of K562/A02 cells, inhibited P-glycoprotein expression (mean fluorescent intensity decreased from 123 ± 13 to 39 ± 13) and increased the intracellular concentration of ADM (mean fluorescent intensity increased from 18 ± 5 to 34 ± 6) in K562/A02 cells. Luciferase reporter gene assay demonstrated that TPL inhibited the transcriptional activity of MDR1 promoter by 75%. It is concluded that TPL may effectively reverse the multidrug resistance in K562/A02 cells via modulating P-glycoprotein expression and increasing intracellular ADM accumulation.