Carbonaceous-TiO2 nanomaterials for photocatalytic degradation of pollutants: A review

Semiconductor photocatalysis is one of most appealing and attractive technologies, which has been directly utilized to harvest solar energy for energy and environmental applications. Titanium dioxide (TiO₂) has been proved to be leading semiconductor photocatalyst for the degradation of pollutants. However, it suffers from low photocatalytic activity under visible light activation because of its intrinsic wide band gap. Various strategies have been developed to enhance TiO₂ efficiency in the visible light region. Among them TiO₂ modification with carbonaceous nanomaterials is very effective route for excellent photocatalytic activity. This critical review aims to present recent progress in the design and synthesis of carbonaceous-TiO₂ photocatalysts, covering carbon doping, activated carbon, fullerenes, carbon nanotubes and graphene. Moreover, proposed mechanisms of enhancement, effect of synthesis routes, demonstrations of performance and applications reported in literature are reviewed. Ongoing challenges and possible new directions are outlined.     

Hydrogen peroxide production by water electrolysis: Application to disinfection

Hydrogen peroxide was produced by direct current electrolysis using only two electrodes, a carbon felt cathode and a RuO₂ coated titanium anode. The required oxygen was supplied by oxidation of water and by transfer from the atmosphere or by pure oxygen injection. The current was maintained below a maximum value to avoid peroxide reduction. A high peroxide production rate was reached and a 15 mg l^–1 concentration was maintained. The electrolysis removed turbidity and dissolved organic carbonaceous compounds from municipal sewage plant effluents. Real effluents were significantly disinfected owing to the direct effect of electric current and the indirect effect of peroxide. A residual effect was also observed.     

多孔纳米材料改性水处理超滤膜的研究进展

基于压力驱动的超滤膜面临渗透性和选择性的制衡及膜污染问题。多孔纳米材料是高性能超滤膜改性制备中一类重要的添加剂,是新型水处理功能膜的研究热点之一。多孔纳米材料的添加为膜提供了额外水通道,其可调的孔尺寸又为在膜内构建出具有高度选择性的纳米通道提供了潜在有利条件,进而突破膜渗透性和选择性的Trade-off效应。同时,亲水性多孔纳米材料的添加有利于提升膜的抗污染性能。本文综述了近年来多孔纳米材料对超滤膜的改性方法,总结了微孔沸石分子筛、介孔炭、介孔二氧化硅、金属有机骨架材料和共价有机骨架材料对超滤膜的改性研究进展,着重评价了不同改性材料对超滤膜在亲水性、渗透性、污染物截留和抗污染能力等方面的影响。最后对未来多孔纳米材料改性超滤膜的研究及应用的发展趋势进行了展望。     

光催化材料去除水中病毒的研究进展

光催化技术凭借其稳定高效且成本低等优势,应用于水消毒领域的研究逐渐受到重视。光催化剂生成的一系列活性氧物种能有效灭活水中病原微生物。由于病毒与细菌等其他微生物结构、抗性等不同,因此本文着重综述了光催化材料应用于去除水中病毒的研究进展。介绍了光催化技术的氧化和消毒原理,评价了传统消毒工艺去除病毒的优缺点,总结了TiO₂基光催化剂和不含TiO₂的光催化材料的应用现状。最后展望未来光催化材料设计应以降低制备成本、提高光催化效率、能实际大规模工程化应用的方向发展。     

基于二维纳米材料的水处理功能膜研究进展

二维纳米材料是制备膜材料中一类重要的掺杂材料或膜构筑单元,也是新型水处理功能膜的研究热点。已有许多研究报道了二维纳米材料通过有序的堆叠和自组装在膜内构建出规整的水通道,可以赋予膜可调控的分离性能,进而实现trade-off效应的突破,被认为是“下一代膜材料”（next-generation membranes）。同时,二维纳米材料的独特片层结构、催化性能及可修饰性可使膜材料获得新的功能,如导电性能、光/电催化性能等。本文综述了近年来基于二维纳米材料的水处理功能膜研究进展,重点介绍了共混法、自组装等制备方法,并总结了此类功能膜在抗污染、膜通量恢复、强化污染物去除、调控盐截留及污染物监测领域的应用。最后对基于二维纳米材料的水处理功能膜发展方向,如限域催化、调控盐分离、监测传感等新兴领域进行了分析和展望。     

二氧化钛基光催化材料的制备与应用

光催化降解环境污染物具有反应条件温和、无毒无害、不产生二次污染和处理费用低廉等优点,能降解绝大多数有毒有害化学物质,是很有前途的环保方法。讨论了TiO2的主要制备方法,介绍了改进TiO2光催化活性的一些方法,对近年来二氧化钛基光催化材料在有机工业污水处理及无机废水净化方面的应用进行了评述,对该材料的发展趋势进行了展望。     

光催化技术在水处理中的研究进展及挑战

利用太阳光去除有机污染物和有害细菌的光催化技术一直被认为是水处理中最有使用价值的技术之一,因为其具有操作简便、不引入二次污染、能源清洁等优点而在环境净化领域具有巨大的应用潜力,近些年在水和空气净化中被广泛研究。本文介绍了光催化技术的基本机理并分析了影响光催化效率的因素,总结了包括表面光敏化、离子掺杂改性等提高光催化效率的手段,回顾了近些年光催化技术在饮用水处理及废水处理领域当中的研究应用情况,将光催化技术与生物法、膜法等传统技术结合应用并对其机理进行探究,有助于进一步发展基于可见光作为清洁、可再生能源驱动的光催化环境修复技术。重点关注光催化技术在环境保护,尤其是水处理领域的发展潜力,并对于光催化技术未来的发展方向进行了展望。     

单过硫酸氢钾复合盐的消毒研究与应用进展

单过硫酸氢钾复合盐作为一种高效、安全的消毒剂和氧化剂已经在给水消毒、废水处理、水产养殖等领域得到广泛应用。整理了单过硫酸氢钾复合盐消毒相关的基本性质、消毒效能与影响因素的近期研究结果和主要消毒应用,并对消毒副产物的安全性进行讨论。发现即使已经出现了大量的消毒理论与应用研究报道和案例,但与其他消毒剂相比单过硫酸氢钾复合盐的消毒研究在深度与广度上仍有差距。应当继续充实单过硫酸氢钾复合盐的基础研究工作、完善法规与标准,为拓展其应用领域、发挥其潜在价值提供技术与政策支持。     

氮掺杂碳纳米材料在氧还原反应催化剂中的研究进展

长期以来,碳材料负载高分散的铂催化剂及其合金材料一直是商业化质子交换膜燃料电池（PEMFC）中氧还原反应和氢氧化反应十分有效的催化剂。但由于Pt基催化剂成本高、电化学条件下稳定性差、易CO中毒以及氧还原反应（ORR）动力学迟缓等一系列问题,阻碍了其在燃料电池中的进一步应用和大规模生产。相比之下,氮掺杂碳纳米材料具有低成本、高活性、高稳定性、环境友好等特点,这些优异的性能使其在燃料电池领域有着广阔的应用前景。结合近几年国内外研究现状,综述了原位掺杂法、后掺杂合成法和直接热解法等3种氮掺杂碳纳米材料的制备方法,并分析了各自的优点和不足之处,及其作为ORR催化剂的研究进展。最后,对未来氮掺杂碳纳米材料催化剂研究的主要发展方向进行了展望。     

导电高分子纳米材料的制备方法研究现状

导电高分子纳米材料不仅具有一定的导电性能,而且兼具纳米材料的特殊性能,因而在很多领域具有广泛的应用前景。本文将导电高分子纳米材料的制备方法分为模板法和无模板法两大类进行探讨,模板法又分为硬模板和软模板法,主要以聚苯胺的制备进行举例,对每种方法的优缺点进行了分析,并对导电高分子纳米材料的未来发展进行了展望。     

半导体多相光催化氧化技术

阐述了半导体多相光催化氧化的特点、机理及其应用 ,总结了半导体光催化剂的种类、制备。指出了设计光催化反应器所要考虑的主要方面 ,对影响光催化反应的因素进行了简要分析。     

纳米光热材料在抗菌领域的研究进展

耐药菌的出现极大提高了临床发病率及死亡率,并对人们的生活及医疗系统造成了很大的冲击。耐药菌的快速变异和新抗生素研发的滞后,迫切需要新的抗菌手段以应对上述问题。光热疗法（PTT）是一种将太阳能转换成热能（光热转换）,提高局部温度,进而杀死细菌的新型抗菌技术。PTT具有独特的抗菌机制,产生耐药菌的可能性较低,在抗菌领域具有独特的优势。各种具有光热转换效果的纳米粒子以及基于此设计的纳米复合材料是PTT的关键。该文综述了近年来光热剂（PTAs）在抗菌领域的研究进展,总结了PTAs的种类及应用领域,对PTT抗菌发展存在的问题进行了分析,对未来研究的重点和方向进行了展望,以期对PTAs抗菌材料的研究提供新的思路。     

纳滤/反渗透技术去除水中含氮消毒副产物的研究进展

以卤乙腈(HANs)、卤代硝基甲烷(HNMs)、亚硝胺(NAs)、卤乙酰胺(HAcAms)为典型代表的含氮消毒副产物(N-DBPs)具有强烈的细胞毒性和遗传毒性.纳滤(NF)膜和反渗透(RO)膜在空间位阻和静电排斥等机理的作用下,对水中微量有机污染物去除效果较好.阐述了NF膜和RO膜的去除机理及影响因素,探讨了其对水中...     

Synthesis and photocatalytic activity of BiFeO3 and Bi/BiFeO3 cubic microcrystals

BiFeO₃ and Bi/BiFeO₃ cubic microcrystals were synthesized in this work. The phase, microstructure, optical and photo electrochemical properties, as well as the photocatalytic activities in photocatalytic hydrogen generation were investigated. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results demonstrate the successful synthesis of BiFeO₃ and Bi/BiFeO₃. The scanning electron microscope (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray (EDX) results give the evidence of cubic morphology and the deposition of metal Bi on the surface of BiFeO₃. The absorption spectra show that Bi/BiFeO₃ has longer absorption edge and stronger absorption capability to visible light. The photocurrent curves, emission spectra, and electrochemical impedance spectroscopy (EIS) spectra demonstrate that Bi/BiFeO₃ has higher efficiency of electron-hole separation and charge transfer, as well as longer lifetime of the charge carriers. These benefit to the enhancement of activity in photocatalytic hydrogen generation.     

Comparative evaluation of Fe and TiO2 photoassisted processes in solar photocatalytic disinfection of water

A lost of culturability of bacteria Escherichia coli K12 was observed after exposition to a solar simulator (UV–vis) in a laboratory batch photoreactor. The bacterial inactivation reactions have been carried out using titanium dioxide (TiO₂) P25 Degussa and FeCl₃ as catalysts. At the starting of the treatment, the suspensions were at their “natural” pH. An increase in the efficiency in the water disinfection was obtained when some advanced oxidation processes such as UV–vis/TiO₂, UV–vis/TiO₂/H₂O₂, UV–vis/Fe³⁺/H₂O₂, UV–vis/H₂O₂ were applied. The presence of H₂O₂ accelerates the rate of disinfection via TiO₂. The addition of Fe³⁺ (0.3 mg/l) to photocatalytic system decreases the time required for total disinfection (<1 CFU/ml), for TiO₂ concentrations ranging between 0.05 and 0.5 g/l. At TiO₂ concentrations higher than 0.5 g/l the addition of Fe³⁺ does not significantly increase the disinfection rate. The systems: Fenton (H₂O₂/Fe³⁺/dark), H₂O₂/dark, H₂O₂/TiO₂/dark showed low disinfection rate. The effective disinfection time (EDT₂₄) was reached after 60 and 30 min of illumination for the Fe³⁺ and TiO₂ photoassisted systems, respectively. EDT₂₄ was not reached for the system in the absence of catalyst (UV–vis). The effect on the bacterial inactivation of different mixture of chemical substance added to natural water was studied.     

石墨烯/TiO2复合材料光催化降解有机污染物的研究进展

石墨烯是一种新型的碳纳米材料,具有超大的比表面积和优良的导电性能,将石墨烯与TiO₂复合可显著提高复合材料的光催化性能,在光催化领域具有广泛的应用前景。主要介绍了石墨烯/TiO₂复合纳米材料的制备方法以及在光催化降解有机污染物方面的应用,并分析了石墨烯/TiO₂复合材料促进光催化机理,最后对石墨烯/TiO₂复合光催化剂未来的发展趋势提出了展望。     

Recent progress in two-dimensional nanomaterials of graphene and MXenes for thermal camouflage

Thermal camouflage is one of the most effective ways to guarantee the security and survival of military objects against infrared (IR) detectors. However, with the rapid development of IR detection technology, the IR thermal camouflage of objects and weapons has become more and more difficult, and advanced thermal camouflage materials are urgently needed to meet the demands of warfare. So far, two dimensional (2D) nanomaterials have demonstrated excellent performances with low IR emissivity, optoelectronic tunability, and compatible stealth capabilities. Among them, graphene and MXenes are the most attractive 2D materials used for thermal camouflage applications. Here we present a review of recent progress on the thermal camouflage properties of graphene and Ti₃C₂T_x MXene in the form of composite film, microcapsule and aerogel structures, a summary of current understanding of the working principle of thermal camouflage materials, and current limitations and future opportunities in graphene and Ti₃C₂T_x MXene research and development.