RESUMO
Although less toxic than hexavalent chromium, Cr (â ¢) species still pose a threat to human health. The Cr (â ¥) should be converted to Cr (0) instead of Cr (â ¢), which is still involved in biological detoxification filed. Herein, for the first time, it was found that Cr(â ¥) can be reduced into Cr(0) by Bacillus cereus FNXJ1-2-3, a way to completely harmless treatment of Cr(â ¥). The bacterial strain exhibited excellent performance in the reduction, sorption, and accumulation of Cr(â ¥) and Cr (â ¢). XPS etching characterization inferred that the transformation of Cr(â ¥) into Cr(0) followed a reduction pathway of Cr(â ¥)âCr (â ¢)âmetallic Cr(0), in which at least two secretory chromium reductases (ECrâ ¥ââ ¢ and ECrâ ¢â0) worked. Under the optimum condition, the yield ratio of Cr(0)/Cr (â ¢) reached 33.90%. In addition, the interfacial interactions, ion channels, chromium reductases, and external electron donors also contributed to the Cr(â ¥)/Cr(0) transformation. Findings of this study indicate that Bacillus cereus FNXJ1-2-3 is a promising bioremediation agent for Cr(â ¥) pollution control.
Assuntos
Bacillus cereus , Biodegradação Ambiental , Cromo , Bacillus cereus/metabolismo , Cromo/metabolismo , Adsorção , Poluentes Químicos da Água/metabolismoRESUMO
An interfacial structure is crucial to the photoinduced electron transport for a heterostructure photocatalyst. Constructing an interfacial electron channel with an optimized interfacial structure can efficiently improve the electron-transfer efficiency. Herein, the rapid electron-transfer channels were built up in a Cu2O/SrFe0.5Ta0.5O3 heterojunction (Cu2O/SFTO) based on the selective bonding effect of heterologous surface oxygen vacancies in the SFTO component. The heterologous surface oxygen vacancies, namely, VO-Fe and VO-Ta, respectively, adjacent to Fe and Ta atoms, were introduced into fabricating the Z-scheme Cu2O/SFTO heterojunction. Compared with sample Cu2O/SFTO with VO-Fe, the photocatalytic NO removal efficiency of sample Cu2O/SFTO with VO-Fe and VO-Ta was increased by 22.5%. The enhanced photocatalytic performance originated from the selective bonding effect of heterologous VO-Fe and VO-Ta on the interfacial electron-separating and -transfer efficiency. VO-Fe is the main body to construct the interfacial electron-transfer channels by forming interfacial Fe-O-Cu(I) bonds, which causes lattice distortion at the interface, and VO-Ta can optimize the structure of interfacial channels by balancing the electron density of SFTO to control the average space of the interface transition zone. This research provides a new cognitive perspective for constructing double perovskite oxide-based heterostructure photocatalysts.
RESUMO
Thiomolybdate [Mo3S13]2- nanoclusters, as a molecular mimic of MoS2 edge sites, showed high efficiency in catalyzing photochemical H2 evolution from a molecular system of Ru(bpy)3Cl2-ascorbic acid (H2A) under visible light irradiation (≥420 nm), providing a turnover number of 1570 and an initial turnover frequency of 335 h-1 for H2 evolution based on the [Mo3S13]2- catalyst.
RESUMO
CoAl-layered double hydroxide nanosheets (CoAl-NSs) could serve as an active matrix to effectively anchor amorphous MoSx nanoparticles with high dispersion and the formation of an additional active "CoMoS" phase. The resulting CoAl-NSs/MoSx catalyst showed 13 times higher H2 evolution activity than free MoSx nanoparticles from an erythrosin B-triethanolamine (ErB-TEOA) system under visible light.