藏北退化高寒草原土壤细菌和真菌多样性分析

藏北高寒高原为西藏自治区主要牧区。在人类因素和自然因素双重作用下,目前藏北高寒草原退化程度比较高,严重影响当地社会?经济和环境健康与生态安全的可持续发展。草原退化的重要标志之一是土壤质量退化,特别是土壤微生物多样性明显下降,因此,探究藏北退化高寒草原土壤质量以及细菌和真菌多样性对评价其生态系统结构和功能具有重要作用。运用宏基因组学方法,基于高通量测序技术,对藏北退化高寒草原土壤细菌和真菌群落多样性进行分析。结果显示,藏北退化高寒草原土壤化学成分组成以SiO_2为主,占比为63.5%。土壤颗粒粒径分布介于10~0.1 mm之间,其中介于5~1 mm之间土壤颗粒占比为51%。细菌多样性、丰富度和相对丰度均显著高于真菌。放线菌门、变形菌门和酸杆菌门是藏北退化高寒草原土壤细菌群落的优势门类,占比分别为44.9%、16.4%和14.5%;而土壤真菌群落的优势门类主要为子囊菌门、其他类和担子菌门,占比分别为71.5%、14.3%和8.3%。通过对细菌和真菌多样性、丰富度和相对丰度进行计算,得出真菌/细菌比仅分别为0.725、0.260和0.258,表明藏北高寒草原土壤肥力已比较低下,且生态系统呈退化趋势。

Pt nanoparticles encapsulated on V_(2)O_(5)nanosheets carriers as efficient catalysts for promoted aerobic oxidative desulfurization performance

Platinum group metals(PGMs)usually exhibit promising aerobic catalytic abilities,providing a green and feasible oxidative desulfurization method.However,often,the PGM nanoparticles(NPs)get leached,and the catalysts are deactivated.In this work,Pt NPs with particle sizes of approximately 4–5 nm were encapsulated effectively and uniformly on the surface of vanadium pentoxide(V2O5)nanosheets(with thicknesses of approximately six atomic layers)through strong metal-support interactions.The synthesized catalysts promote catalytic aerobic oxidation reactions,realizing deep desulfurization(99.1%,<5μg g^(–1))under atmospheric pressure and 110℃reaction temperature.Remarkable degrees of sulfur removal could be achieved for oils with different initial S-concentrations and substrates.Additionally,the as-prepared catalysts could be recycled for reuse at least seven times.

Hydrochloric acid‐mediated synthesis of ZnFe_(2)O_(4) small particle decorated one‐dimensional Perylene Diimide S‐scheme heterojunction with excellent photocatalytic ability

The recyclable and stable ZnFe_(2)O_(4) small particle decorated one‐dimensional perylene diimide(PDI)S‐scheme heterojunction(1D PDI/ZnFe_(2)O_(4))is prepared by the hydrochloric acid‐mediated(HCl‐mediated)strategy,interestingly,the morphology of the 1D PDI/ZnFe_(2)O_(4) can also be effectively regulated by HCl‐mediated process,the existence of HCl can regulate PDI into a uniform rod structure,while the co‐existence of HCl and PDI can limit ZnFe_(2)O_(4) to become the uniform small particles.More importantly,based on the 1D rod structure of PDI and the small size effect of ZnFe_(2)O_(4),carriers can migrate to the surface more easily,which can improve the photocatalytic activity.Meanwhile,due to the appropriate energy level structure,the S‐scheme heterojunction structure is formed between PDI and ZnFe_(2)O_(4),which eliminates meaningless photo‐generated charge carriers through recombination and introduces strong redox to further enhance the photodegradation effect,thereby,1D PDI/ZnFe_(2)O_(4) exhibits excellent photocatalytic ability,under the visible light irradiation,the degradation rate of tetracycline(TC)with 1D PDI/ZnFe_(2)O_(4)(66.67%)is 9.18 times that with PDI(7.26%)and 9.73 times that with ZnFe_(2)O_(4)(6.85%).This work proposes new ideas for the assembly of magnetic organic‐inorganic S‐scheme heterojunction photocatalysts.