Nanotechnology‐based wastewater treatment

Water contamination is a global challenge impacting both the environment and human health with significant economic and social costs. The growing scarcity of usable water resources requires effective treatment of wastewater. In this context, developing cheaper, safer and more efficient wastewater treatment technologies are the need of the hour. One promising approach that several studies have reported success has been the usage of nanomaterials in water and waste water management. The rapid progress of research in nanomaterial sciences has shown their growing potential; however, there has not been a great amount of information available on their implementation. This review focuses on developments in nanotechnology that hold strong potential for wastewater treatment. The review covers key techniques in nanomaterial‐based water treatments including adsorption, filtration and photocatalysis with recent examples showing how to improve their properties and efficiencies according to the need.     

One-step scalable preparation of graphene nanosheets and high-thermal-conductivity flexible graphene films

It is well known that graphene nanosheets (GNSs) have many excellent properties. However, it has been a difficult thing to exfoliate graphite into GNSs in a controllable and scalable manner. In this research, a new strategy named xylitol-assisted ball milling exfoliation (XABME) was developed for the scalable preparation of GNSs. The experimental results characterized by a series of measurements showed that GNSs were successfully exfoliated by the XABME strategy. The structure of the prepared nanosheets was featured by large lateral size and ultra-small thickness. Furthermore, the prepared GNSs easily achieved high production yield (≈54%). Lastly, the as-obtained GNSs and cellulose nanofibers (CNF) were compounded to form some nanomaterial films. The prepared films exhibited excellent flexibility and higher thermal conductivity, with the in-plane thermal conductivity of 90 wt% GNS film (8.0 W/(m·K)) being 11.4 times higher than that of the film without GNSs. This shows that GNSs could effectively enhance the thermal conductivity of the CNF matrix and indicate that these prepared films have great potentials in the thermal management of portable mobile devices.     

表面科学与工程在纳米技术发展与应用中的直接作用

表面科学与工程在纳米技术的发展与应用中发挥着特殊的作用，尤其在纳米尺度材料的制备和纳米制造等领域。在纳米材料领域，纳米晶块材料的界面问题和纳米尺度的分子自组装的表面与界面问题是极富挑战性的前沿工作。在纳米制造领域，微机械部件的微纳米尺度的操作手设计和运动副表面的微观失效、摩擦磨损和润滑等问题也将开辟表面科学与工程新的研究领域。     

Stimuli-Responsive Nanomaterials for Smart Tumor-Specific Phototherapeutics

Phototherapy, a type of photoresponsive regulation of biological activities, together with additional stimuli-responsive features, offers significant potential for enhancing the precision and efficacy of cancer treatments. To achieve tumor-specific therapeutics, numerous studies have focused on the development of smart phototherapeutic nanomaterials (PNMs) that can respond to endogenous pathological characteristics (e. g., mild acidity, the overproduction of glutathione, the overproduction of hydrogen peroxide, the overexpression of specific surface receptors, etc.) present in the tumor and/or exogenous stimuli. Such responsiveness can effectively improve the physicochemical properties, cellular uptake, tumor-targeting performance, and pharmacokinetic profile of PNMs. Herein, we will systematically discuss recent advances in this field. Moreover, potential challenges and future directions in the development of stimuli-responsive PNMs are also presented to support the development of this emerging cutting-edge research area.     

Nanoindentation Characterization of Submicro- and Nano-Sized Liquid-Phase-Sintered SiC Ceramics

Submicro- and nano-sized liquid-phase-sintered SiC ceramics were mechanically tested by nanoindentation in the peak load range 5–400 mN. The submicro-sized sample showed a marked indentation size effect which the nano-sized samples did not exhibit. The relevance of indentation depth with respect to the microstructural scale has been outlined. In the investigated grain-size range, the hardness dependence on the grain size could be described by a load-dependent inverse Hall–Petch relation. Young's modulus was less microstructure- and load-dependent. Because of the very fine microstructure, the nano-sized SiC materials gave lower elastic values than the submicro-sized SiC ceramic.     

纳米材料在提高采收率中的研究进展?

近年来，纳米材料因其有吸引力的物化特性已在生物医药、电子储能、保护涂层等领域发挥重要作用。随着石油资源的需求不断增加和开采难度提高，石油勘探和提高石油采收率技术需要不断创新，以满足未来对碳氢燃料的需求。将功能化的纳米材料与提高采收率技术结合，可以改善驱替剂的流变性能，改变储层岩石的润湿性、降低油水界面张力、提高原油的流动性等，进一步提高原油采收率，为油田的有效、可持续开发提供新的技术手段。本文首先综述了当前在提高采收率领域中的应用较多的几类纳米材料；之后，对纳米材料在提高采收率中的作用机理做了总结；最后，讨论了纳米材料在提高采收率技术中存在的问题，并对其发展趋势进行了展望。     

Formation of bulk ferromagnetic nanostructured Fe_(40)Ni_(40)P_(14)B_6 alloys by metastable liquid spinodal decomposition

Nanostructured Fe40Ni40P14B6 alloy ingots of 3―5 mm in diameter could be synthesized by a metastable liquid state spinodal decomposition method. For undercooling T> 260 K, the microstructure of the undercooled specimen had exhibited liquid state spinodal decomposition in the undercooled liquid state. The microstructure could be described as two intertwining networks with small grains dispersed in them. For undercooling T>290 K, the overall microstructure of the specimen changed into a granular morphology. T...     

Graphene oxide-containing isocyanate-based polyimide foams: Enhanced thermal stability and flame retardancy

Isocyanate-based graphene oxide-containing polyimide foams were synthesized by a semi-prepolymer method. In this method, while the first solution containing pre-polymer was derived from pyromellitic dianhydride and excess polymethylene polyphenylene isocyanate (PM200), the second solution contains dianhydride derivatives, water, catalysts, surfactants, and graphene oxide. PIFs were prepared with 0%, 0.25%, 0.50%, 0.75%, and 1% graphene oxide by weight, respectively. PIFs exhibited a minimum side reaction and urea generation was not seen for all PIFs instead of imide bonding. The addition of graphene oxide (GO) leads to a more close-packed structure. Therefore, crosslinking density and thermal stability of graphene oxide-containing polyimide foams increased. Upon the addition of 1% GO, almost seven times higher compression strength was obtained compared to neat PIFs. Also, LOI values supported the theory that thermally stable and flame retardant PIFs can be synthesized via the isocyanate-based process with GO.     

Preparation and lithium storage properties of Mo2N quantum dots@nitrogen-doped graphene composite

To improve the electrochemical lithium storage performance of molybdenum nitrides, Mo₂N quantum dots@nitrogen-doped graphene oxide sponge (Mo₂N-QDs@Ngs) was prepared by hydrothermal reaction, freeze-drying and calcination in H₂/N₂ mixture with ammonium molybdate ((NH₄)Mo₇O₂₄·4H₂O), hexamethylenetetramine (C₆H₁₂N₄) and graphene oxide (GO) as raw materials. The effect of GO content on the electrochemical lithium storage performance was investigated. The transmission electron microscope (TEM) results show that the size of the prepared Mo₂N quantum dots is about 2—5 nm, and the Mo₂N quantum dots are uniformly distributed on the surface of nitrogen-doped graphene. The electrochemical test results show that when the GO content is 30%, the prepared Mo₂N-QDs@Ngs-30 has the best electrochemical lithium storage performance, which has 699 mA·h·g^-1 specific capacity at the current density of 0.1 A·g^-1, and has 286 mA·h·g^-1 specific capacity even at the current density of 2 A·g^-1.     

Mn掺杂对La0.68Pb0.32FeO3纳米材料电阻率、气敏性能的影响

采用Sol-gel法合成了系列纳米材料La0.68Pb0.32Fe1-xMnxO3（x=0．0，0．1，0．2，0．4，0．6），研究了Mn掺杂对材料的导电特性和气敏特性的影响。研究表明：合成的系列纳米材料均具有正交钙钛矿结构，Mn的掺杂对材料La0.68Pb0.32FeO3的结构没有影响，且对材料粒径的影响较小；随Mn元素含量的增加，La0.68Pb0.32Fe-xMnxO3纳米粉体对丙酮的气敏性均迅速降低；Mn掺杂同时导致电阻率减小，这是由于形成Mn^3＋-O^2--Mn^4＋双交换作用键的缘故。