Polymeric Nanocomposites for Environmental and Industrial Applications

Polymeric nanocomposites (PNC) have an outstanding potential for various applications as the integrated structure of the PNCs exhibits properties that none of its component materials individually possess. Moreover, it is possible to fabricate PNCs into desired shapes and sizes, which would enable controlling their properties, such as their surface area, magnetic behavior, optical properties, and catalytic activity. The low cost and light weight of PNCs have further contributed to their potential in various environmental and industrial applications. Stimuli-responsive nanocomposites are a subgroup of PNCs having a minimum of one promising chemical and physical property that may be controlled by or follow a stimulus response. Such outstanding properties and behaviors have extended the scope of application of these nanocomposites. The present review discusses the various methods of preparation available for PNCs, including in situ synthesis, solution mixing, melt blending, and electrospinning. In addition, various environmental and industrial applications of PNCs, including those in the fields of water treatment, electromagnetic shielding in aerospace applications, sensor devices, and food packaging, are outlined.     

Multiwalled Carbon Nanotubes/CsPbX3@Polyacrylonitrile Core/Shell Nanofibers with Ultrahigh Water,Thermal, and Ultraviolet Stability

The application of all-inorganic perovskite nanocrystals (PNCs) is considerably limited by their inherent instability under the ubiquitous environmental conditions with high water content, temperature, and UV intensity. The multiwalled carbon nanotubes (CNTs) are combined with polyacrylonitrile (PAN) for the first time to improve the uniform luminous performance and environmental stability of PNCs, attributing to the dense growth of PNC via lead ions bound with rich carbonylation on CNT surfaces, the excellent characteristics of CNTs (including hydrophobicity, electrical conductivity, specific heat, UV absorption capacity), the weather resistance of PAN polymer, and their synergistic effect. Here, via one-step single-nozzle electrospinning at room temperature, CNTs, PNCs, and PAN are comprised as core–shell nanofibers (i.e., CNTs/PNCs@PAN) with tunable emissions between 472 and 683 nm, covering the visible light range from blue to red. The photoluminescence intensity of CNTs/CsPbBr₃@PAN can be 93%, 91%, and 91% of the initial value, respectively, after being immersed in water for 20 days, heated to 90 °C, and exposed to 365 nm light irradiation for 48 h, which are superior to those of the previously reported PNCs/PAN fibers. The ultrahigh water stability is further proven by CNTs/PNCs@PAN-based sensor for rhodamine 6G solution fluorescence detection.     

Precipitation of cesium lead halide perovskite nanocrystals in glasses based on liquid phase separation

Incorporation of cesium lead halide perovskite nanocrystals (CsPbX₃ PNCs, X = Cl, Br, I) into glasses can significantly improve their stabilities and extend their application areas. Precipitation of CsPbX₃ PNCs in glasses is mainly based on thermal treatment; however, the formation of mechanism is not clarified. Here, several in situ methods are employed to illustrate the precipitation mechanism of CsPbX₃ PNCs. It is found that precipitation of CsPbX₃ PNCs in glasses is based on the liquid phase separation in solid amorphous matrix, followed by crystallization in the supercooled state. Liquid phase separation process determines the composition of CsPbX₃ PNCs, and cooling process has strong effect on the crystallinity and quality of CsPbX₃ PNCs. These results clarify the precipitation mechanism of CsPbX₃ PNCs in glasses and provide important guideline for the development of CsPbX₃ PNCs embedded glasses for opto-electronic applications.     

聚硅酸盐类絮凝剂的研究进展

从聚硅酸盐类絮凝剂研制与发展新经历的４个阶段,概略评术字国内外的研究现状及其进展,分析了各类聚硅酸盐絮凝剂,指出了目前研究中所存在的问题。建议今后聚硅酸盐类絮凝的研究应重点开展;制备新工艺研究,提高产品的絮凝及稳定性;聚硅酸与金属盐之间的相互作用研究,探讨絮凝机理;进一步开展应用研究,确定水处理中的最佳应用和范围。     

水处理电絮凝技术的研究进展与挑战

电絮凝是一种用于处理不同类型饮用水和废水有效的电化学方法,近年来由于其高效地处理大量难处理污染物的能力而受到了广泛的关注。它成功地处理了有机和无机污染物且同时却很少产生副产物。在过去的十年里大量的研究致力于利用电絮凝处理饮用水和废水,从受污染的地下水到受高度污染的炼油厂废水都是其处理范围。本文首先介绍了电絮凝的基本原理及优缺点并回顾了近年来有关电絮凝用于水处理的文献,重点关注当前在饮用水和废水中的具体应用方面取得的成功以及未来应用的潜力。随后分析了影响电絮凝效率的几个因素,最后指出最近的电絮凝大多集中在去除特定污染物的研究上,而没有关注开发模型或工业应用,并且如果能降低电絮凝的成本,此方法将会有一个巨大的突破。     

固相反硝化在水污染治理中的研究进展

水环境中硝酸盐污染是普遍存在的问题。固相反硝化（SPD）技术由于其相对于水基反硝化在水修复中的显著优势而受到越来越多的关注。本文对SPD在水修复中的应用提出了新的看法,介绍了SPD中氮转化的过程和机理,如直接反硝化、异化硝酸盐还原成铵和厌氧氨氧化;讨论了碳底物在SPD中转化的主要过程;研究了SPD的主要局限性,包括碳源可用性低,NO₂^-和N₂O积累,溶解有机碳释放和NH₄⁺的生产,并总结了相关的限制因素;此外,还介绍了一些新的措施来减轻这些限制,如应用可生物降解的聚合物底物和异养自养反硝化HAD过程;最后讨论了同时去除硝酸盐和一些典型污染物以扩大SPD应用的方法。本综述试图提高人们对废水处理或水修复工程中反硝化过程的理解。     

膨润土在环境污染治理方面的研究进展

综述了国内外有关膨润土在环境污染治理方面的研究进展，膨润土及其改性产物（活化膨润土，有机膨胀润土，交联膨润土，有机交联膨润土）由于具有良好的吸附性能，在环境污染治理方面得到了越来越广泛的应用。在对含有机污染物，重金属的废水处理中，膨润土是一种高效吸附剂，欧美国家在土壤和地下水污染的防止和修复方面取得了较大的进展，近年来，有关膨润土用于放射性废物处置的理论研究活跃。     

Nature-derived fibrous nanomaterial toward biomedicine and environmental remediation: Today's state and future prospects

Nanocellulose (NC) among all renewable biopolymers has proven to be one of the most applicable existing nanomaterials, attributed to its fascinating diverse range of physicochemical properties. Herein, this review presents elaborately updates on current research activities focused on developed materials with NC as bycomponent for application particularly in the field of biomedicine and wastewater remediation. A brief introduction on structural properties, production as well as surface features of NC is elucidated. Next, are highlights on usage of nanocellulosic polymeric materials in biomedicine including drug delivery systems, tissue engineering, wound dressing, medical implants and in addition, applications of NC as adsorbent in the field of environmental remediation are also outlined. This section will mainly focus on the consolidation of NC with other additives to develop flexible substrates via incorporation of new functional moieties. Finally, future perspectives as well as main challenges and impediments on working with nanocellulosic-based materials are explored in an effort to ameliorate the development and effective usage of this nanomaterial in biomedicine and water remediation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47878.     

微生物固定化修复技术在氮污染地表水中的应用

地表水中氮污染日益严重,由于氮污染地表水的特殊性,常规修复方法难以发挥高效作用。鉴于微生物固定化修复技术的诸多优点以及在含氮废水中的应用,本文阐述了微生物固定化技术修复氮污染地表水的可行性,并探讨了该技术需要解决的问题及发展趋势。     

光催化技术在水处理中的应用研究进展

光催化技术在水处理领域的应用,既可以提高水质安全,也可以缓解全球能源和水资源短缺问题,是一项具有广泛应用前景的技术。本文首先介绍了光催化技术的基本原理及常用光催化剂的特点,综述了光催化剂技术在饮用水和废水处理应用方面的研究进展及发展方向,重点介绍了光催化技术在饮用水中的除嗅、消毒,在染料废水、含油废水、制药废水、催化还原重金属离子、养殖废水、焦化废水方面的应用,为类似污染水质的处理提供了的参考依据,最后对光催化技术及光催化剂的发展进行了展望。     

生物炭的制备、改性及其在环境修复中应用的研究进展

介绍了生物炭的制备、改性及表征,尤其是在环境修复中的应用。阐述了生物炭常用的制备方法包括热解法、气化法和水热碳化法,指出生物炭的制备原料和条件决定了生物炭的吸附性能。为了提高生物炭的吸附性能,常通过酸、碱、氧化剂、金属氧化物、有机化合物、紫外辐射、等离子体、复合材料、蒸汽及气体吹扫等方式对其进行改性处理,而改性方法的选择主要取决于应用的环境领域。虽然生物炭已在土壤修复及改良、固碳、有机固废堆肥、废水净化及大气污染治理等领域取得了良好的效果,但是生物炭的固碳效果还需要在不同土壤条件进一步验证,生物炭提高土壤质量的原因还需要进一步研究,生物炭去除土壤中有机污染物的作用机理也有待进一步探明。此外,利用生物炭进行环境修复时,应注意生物炭的稳定性问题,以免造成二次污染。综上所述,生物炭在环境修复中具有广阔的应用前景,但也存在一些问题和挑战需要解决。     

聚偏氟乙烯膜在水处理中的应用研究进展

概述了PVDF材料的特点,重点介绍了PVDF膜在给水净化、生活污水处理和中水回用、含油废水、重金属废水、印染废水、焦化废水、含酚废水中的应用进展,最后分析了目前PVDF膜的发展趋势.     

生物矿化在环境保护方面的应用

对生物矿化法固结重金属的研究进行了综合评述.首先对生物矿化机理及过程进行了阐述,接着介绍了细菌、真菌、藻类、动植物等常见的具备矿化能力的生物,以及影响生物矿化的各种因素,最后对生物矿化法在水处理及土壤修复当中的研究进行了介绍.文中对生物矿化法应用于实际所面临的问题以及生物矿化法的可能应用方向进行了探讨.     

超临界水氧化在有机废水处理中的应用

超临界水氧化能彻底分解废水中的有机物,是一种非常有前途的废水处理新技术。综述了超临界水氧化技术的工艺特点、反应机理、反应器特征及国内外在有机废水处理中的应用研究现状,并对其应用前景进行了展望。     

高氯酸盐废水修复技术研究现状

综述了物理修复技术、化学修复技术、生物修复技术以及联合修复技术处理含高氯酸盐废水的作用机理及国内外研究进展。在国外,离子交换法和微生物修复技术已获得应用,认为化学快速修复技术、联合修复技术具有重要的应用前景。     

An overview of carbon nanotubes role in heavy metals removal from wastewater

The scarcity of water, mainly in arid and semiarid areas of the world is exerting exceptional pressure on sources and necessitates offering satisfactory water for human and different uses. Water recycle/reuse has confirmed to be successful and promising in reliable water delivery. For that reason, attention is being paid to the effective treatment of alternative resources of water (other than fresh water) which includes seawater, storm water, wastewater (e.g., dealt with sewage water), and industrial wastewater. Carbon nanotubes (CNTs) are called the technology of 21st century. Nowadays CNTs have been widely used for adsorption of heavy metals from water/ wastewater due to their unique physical and chemical properties. This paper reviews some recent progress (from 2013 to 2018) in the application of CNTs for the adsorption of heavy metals in order to remove toxic pollutants from contaminated water. CNTs are expected to be a promising adsorbent in the future because of its high adsorption potential in comparison to many traditional adsorbents.     

Tuning of shear thickening behavior and elastic strength of polyvinylidene fluoride via doping of ZnO-graphene

ZnO rice like nonarchitects are grafted on the graphene carbon core via a rapid microwave synthesis route. The prepared grafted systems are characterized via XRD, SEM, RAMAN, and XPS to examined the structural and morphological parameters. Zinc oxide grafted graphene sheets (ZnO-G) are further doped in β-phase of polyvinylidene fluoride (PVDF) to prepare the polymer nanocomposites (PNCs) via mixed solvent approach (THF/DMF). β-phase confirmation of PVDF PNCs is done by FTIR studies. It is observed that ZnO-G filler enhances the β-phase content in the PNCs. Non-doped PVDF and PNCs are further studied for rheological behavior under the shear rate of 1–100 s⁻¹. Doping of ZnO-G dopant to the PVDF matrix changes its discontinuous shear thickening (DST) behavior to continues shear thickening behavior (CST). Hydrocluster formation and their interaction with the dopant could be the reason for this striking DST to CST behavioral change. Strain amplitude sweep (10⁻³% -10%) oscillatory test reveals that the PNCs shows extended linear viscoelastic region with high elastic modulus and lower viscous modulus. Effective shear thickening behavior and strong elastic strength of these PNCs present their candidature for various fields including mechanical and soft body armor applications.     

废水生物处理过程对微生物胞内PHA的影响

微生物合成的聚－β－羟基烷酸酯作为一种生物可降解高分子,不仅具有广阔的应用前景,而且在废水生物处理领域具有很高的研究价值。本文首先对微生物利用废水合成ＰＨＡ的代谢机理作了分析,然后分别介绍了与ＰＨＡ有关的两种不同的废水生物处理工艺及其关键影响因素,并对国内外在此领域的研究进展作了论述。     

复合微生物制剂在环境保护中的应用

介绍了复合微生物制剂的组成特点，以及在水体污染治理、生物除臭和土壤修复等环保领域方面的应用，分析了复合微生物制剂在环境防治中存在的问题及解决办法，并对其应用前景进行了分析展望。     

Progressive Freeze Concentration for Volume Reduction of Produced Water and Biodiesel Wastewater

One way to conserve fresh water resources is by reusing water from wastewater. For instance, water can be removed from wastewater through formation of ice crystal layers by progressive freeze concentration (PFC). The application of PFC to remove water from produced water and biodiesel wastewater was assessed through the final concentration of concentrated wastewater and purity of melted ice crystals. No PFC study has been done on these applications. In order to evaluate the efficiency of PFC, the effective partition constant (K) and separation efficiency (S_E) were calculated for the effect of stirring rate and coolant temperature. The results demonstrate that PFC is a more practical method for produced water, as compared to biodiesel wastewater which is based on the value of low K and high S_E.