电感耦合等离子体质谱(ICP-MS)法测定土壤中6种重金属元素的不同前处理方法比较

样品前处理是测定土壤中金属元素的关键步骤,为保障测定结果能如实反应土壤环境状况,比较不同的前处理方法对土壤中6种金属元素的同时提取能力。论文基于电感耦合等离子体质谱技术,采用微波和石墨消解装置,探索消解过程中酸种类、加酸方式、消解装置、赶酸温度等因素对测定土壤标准品和实际样品结果的影响。实验结果表明,样品通过依次加入盐酸、硝酸、氢氟酸、高氯酸,并在160 ℃赶酸的石墨消解方式进行前处理能快速、准确地测定土壤中的Cu、Pb、Zn、Cd、Cr、Ni六种元素,其前处理时长约8.5 h,并且消解成本比微波消解更低。在优化条件下,土壤标准样品中6种金属元素的检测结果的绝对回收率为91.5%~108%,相对标准偏差为0.8%~ 5.4%,方法检出限为0.02 mg/kg ~2 mg/kg。表明方法的灵敏度高、准确度与精密度好,适用于批量土壤样品的分析。     

细长金属管内产生的直流辉光等离子体发射光谱诊断

利用发射光谱法对金属管内形成的稳定氩氮直流辉光等离子体进行了诊断。通过对等离子体发射光谱谱线的研究确定了等离子体中的活性粒子成分;根据氩原子的玻尔兹曼曲线斜率法计算了等离子体中的电子激发温度;采用氮分子第二正带系跃迁(C3Π_u→B3Π_g)的发射谱线计算了等离子体中的氮分子振动温度;研究了电子激发温度和氮分子振动温度随压强的变化特征。研究结果表明,在20 Pa下产生的Ar60%+N₂40%直流辉光等离子体中,活性成分主要是Ar原子、Ar离子、N₂的第二正带系跃迁(C3Π_u→B3Π_g)和N+₂的第一负带系跃迁(B2Π+_u→X2Σ+_g);电子激发温度约为(15 270±250)K;氮分子(C3Π_u)振动温度约为(3 290±100)K;随着压强的增加电子激发温度、分子振动温度逐渐降低。文章的研究结果对细长金属管内表面改性研究具有重要的意义。     

Synergistic Interplay of Dual-Active-Sites on Metallic Ni-MOFs Loaded with Pt for Thermal-Photocatalytic Conversion of Atmospheric CO2 under Infrared Light Irradiation

Infrared light driven photocatalytic reduction of atmospheric CO₂ is challenging due to the ultralow concentration of CO₂ (0.04 %) and the low energy of infrared light. Herein, we develop a metallic nickel-based metal–organic framework loaded with Pt (Pt/Ni-MOF), which shows excellent activity for thermal-photocatalytic conversion of atmospheric CO₂ with H₂ even under infrared light irradiation. The open Ni sites are beneficial to capture and activate atmospheric CO₂, while the photogenerated electrons dominate H₂ dissociation on the Pt sites. Simultaneously, thermal energy results in spilling of the dissociated H₂ to Ni sites, where the adsorbed CO₂ is thermally reduced to CO and CH₄. The synergistic interplay of dual-active-sites renders Pt/Ni-MOF a record efficiency of 9.57 % at 940 nm for converting atmospheric CO₂, enables the procurement of CO₂ to be independent of the emission sources, and improves the energy efficiency for trace CO₂ conversion by eliminating the capture media regeneration and molecular CO₂ release.     

1T相MoS2的制备及在电催化分解水析氢反应中的应用

二硫化钼(MoS₂)已成为电化学析氢反应(HER)中铂催化剂的廉价替代品。1T-MoS₂是MoS₂的金属相，由于其具有优异的导电性和更多的电化学活性位点，因此成为了比2H-MoS₂更具前景的理想催化剂材料。本文综述了1T相MoS₂的制备及在HER中的应用。首先，比较了1T-MoS₂和2H-MoS₂几何结构及电子结构的差异，从“自上而下”及“自下而上”的角度概述了1T-MoS₂常用制备方法，总结1T-MoS₂及1T-MoS₂基材料在HER领域的应用；最后指出现阶段关于1T-MoS₂的研究中仍存在的一些关键问题。     

Antibiotics-loaded nanofibers fabricated by electrospinning for the treatment of bone infections

Electrospinning is one of the most promising fabrication techniques of nanostructured membranes for guided bone regeneration. In association with antibiotics, membranes consisting of fibers with sub-micrometric and nanometric dimensions have been tested to prevent and treat bone infections. Electrospinning was recently applied to produce metallic implant coatings for biofilm inhibition. Despite the numerous in vitro and in vivo studies conducted with nanofibers from several polymeric matrices and fabrication methods, there is no consensus on the best conditions to optimize their antimicrobial activity. This study analyzed recent advances in nanofiber fabrication by the electrospinning technique for clinical applications in the treatment of bone infections. An integrative review from MEDLINE/PubMed, Web of Science, and Scielo databases selected 16 works focused on nanofibers' in vitro and in vivo evaluations. It was found that manufacturing methods significantly influence fiber composition, structure, morphology, pore size, and biodegradability. Thus, standardizing these parameters in the production of nanofibers at an industrial scale is one of the challenges in improving drug loading control on the fiber network and its release profiles. Further in vivo studies need to be conducted to optimize the dose effect of antibiotic-loaded membranes in inhibiting the proliferation of pathogens and inflammatory processes without promoting toxicity and reducing bone regenerating capacity.