Activity and Stability Boosting of an Oxygen-Vacancy-Rich BiVO4 Photoanode by NiFe-MOFs Thin Layer for Water Oxidation.

The introduction of oxygen vacancies (Ov) has been regarded as an effective method to enhance the catalytic performance of photoanodes in oxygen evolution reaction (OER). However, their stability under highly oxidizing environment is questionable but was rarely studied. Herein, NiFe-metal-organic framework (NiFe-MOFs) was conformally coated on oxygen-vacancy-rich BiVO4 (Ov-BiVO4 ) as the protective layer and cocatalyst, forming a core-shell structure with caffeic acid as bridging agent. The as-synthesized Ov-BiVO4 @NiFe-MOFs exhibits enhanced stability and a remarkable photocurrent density of 5.3±0.15 mA cm-2 at 1.23 V (vs. RHE). The reduced coordination number of Ni(Fe)-O and elevated valence state of Ni(Fe) in NiFe-MOFs layer greatly bolster OER, and the shifting of oxygen evolution sites from Ov-BiVO4 to NiFe-MOFs promotes Ov stabilization. Ovs can be effectively preserved by the coating of a thin NiFe-MOFs layer, leading to a photoanode of enhanced photocurrent and stability.

Burkholderia metalliresistens sp. nov., a multiple metal-resistant and phosphate-solubilising species isolated from heavy metal-polluted soil in Southeast China.

A metal-resistant and phosphate-solubilising bacterium, designated as strain D414(T), was isolated from heavy metal (Pb, Cd, Cu and Zn)-polluted paddy soils at the surrounding area of Dabao Mountain Mine in Southeast China. The minimum inhibitory concentrations of heavy metals for strain D414(T) were 2000 mg L(-1) (Cd), 800 mg L(-1) (Pb), 150 mg L(-1) (Cu) and 2500 mg L(-1) (Zn). The strain possessed plant growth-promoting properties, such as 1-aminocyclopropane-1-carboxylate assimilation, indole production and phosphate solubilisation. Analysis of 16S rRNA gene sequence indicated that the isolate is a member of the genus Burkholderia where strain D414(T) formed a distinct phyletic line with validly described Burkholderia species. Strain D414(T) is closely related to Burkholderia tropica DSM 15359(T), B. bannensis NBRC E25(T) and B. unamae DSM 17197(T), with 98.5, 98.3 and 98.3 % sequence similarities, respectively. Furthermore, less than 34 % DNA-DNA relatedness was detected between strain D414(T) and the type strains of the phylogenetically closest species of Burkholderia. The dominant fatty acids of strain D414(T) were C14:0, C16:0, C17:0 cyclo and C18:1 ω7c. The DNA G+C content was 62.3 ± 0.5 mol%. On the basis of genotypic, phenotypic and phylogenetic data, strain D414(T) represents a novel species, for which the name Burkholderia metalliresistens sp. nov. is proposed, with D414(T) (=CICC 10561(T) = DSM 26823(T)) as the type strain.

[Pollution Characteristics, Source Analysis, and Health Risk Assessment of Heavy Metals in Soil and Crops in a Typical molybdenum Mining Area of Qinling Mountains].

This study focused on a molybdenum mining area in the Qinling Mountains （Shaanxi segment）. Crop and corresponding soil samples were collected from the vicinity of the mining area, and the concentrations of six heavy metals （Cr, Cu, Zn, As, Cd, and Pb） were determined. Soil heavy metal pollution was assessed using single-factor, comprehensive pollution, and geo-accumulation index methods. The primary sources of soil heavy metals were analyzed using the PMF model. A health risk assessment for soil and crops was conducted using the USEPA model. The results revealed severe pollution of agricultural soils by Cr, Cu, Zn, Cd, and Pb. Among these, Cr may have been primarily sourced from chrombismite nearby mining activities, contributing to 85.1% of the pollution. Cu and As were mainly sourced from agriculture, contributing 50.3% and 70.6%, respectively. Zn and Cd were primarily sourced from natural sources such as metal slag dust and rainwash from the mining area, contributing 73.5% and 48.7%, respectively. Pb was primarily sourced from transportation sources, contributing to 54.7% of the pollution. Crop metal contamination was especially severe for Cr, followed by Pb, whereas As and Cd contamination was relatively lower. Crops were significantly impacted by heavy metal pollution in agricultural soils. The health risk assessment indicated non-carcinogenic and carcinogenic risks for children due to soil heavy metals, whereas adults faced acceptable levels of risk. Both adults and children were exposed to highly significant non-carcinogenic and carcinogenic risks from heavy metals in the crops. Moreover, it is essential to implement effective measures to control heavy metal pollution from tailings to safeguard nearby residents, especially children, from adverse health risks.

Enhance antimony adsorption from aquatic environment by microwave-assisted prepared Fe3O4 nanospherolites.

A novel hierarchically nanostructured magnetite (Fe3O4) was manufactured using microwave-assisted reflux method without surfactants. The nanostructured Fe3O4 is formed via the co-precipitation of Fe(III) and Fe(II), followed by a nanocrystal aggregation-based mechanism. Moreover, the effects of solution pH, contact time, initial Sb concentration, coexisting anions, and recycle numbers on the adsorption of nanostructured Fe3O4 toward Sb were extensively examined in the batch adsorption tests. The results demonstrated that the obtained Fe3O4 exhibited excellent adsorption ability toward Sb with the maximum adsorption capacities of 154.2 and 161.1 mg.g-1 for Sb(III) and Sb(V), respectively. The prepared Fe3O4 could be easily regenerated and reused for adsorption/desorption studies multiple times without compromising the Sb adsorption ability. Further exploration indicated that the oxidation or reduction reactions infrequently occurred during Sb adsorption processes. The proposed hierarchically nanostructured Fe3O4 thus could be potentially used for sustainable and efficient antimony removal.

Streptomyces plumbiresistens sp. nov., a lead-resistant actinomycete isolated from lead-polluted soil in north-west China.

The taxonomic position of an actinomycete isolated from a lead-polluted soil in Gansu province, north-west China, was determined by using a polyphasic approach. Chemical and morphological properties of the isolate, designated strain CCNWHX 13-160(T), were similar to those of streptomycetes. Analysis of the almost complete 16S rRNA gene sequence placed strain CCNWHX 13-160(T) in the genus Streptomyces where it formed a distinct phyletic line with recognized Streptomyces species. The strain was most similar to Streptomyces pseudovenezuelae NBRC 12904(T) (98.9 %) and Streptomyces resistomycificus NBRC 12814(T) (98.8 %). Furthermore, DNA-DNA hybridization studies between the novel isolate and these two strains showed relatedness values of 49.7+/-0.8 and 43.2+/-1.1 %, respectively. It is proposed that strain CCNWHX 13-160(T) (=ACCC 41207(T)=HAMBI 2991(T)) be classified as the type strain of a novel species in the genus Streptomyces, Streptomyces plumbiresistens sp. nov. The MIC of Pb(2+) for growth of strain CCNWHX 13-160(T) was 4.0 mM.