改性活化过硫酸盐应用及机理研究进展

生物炭(BC)由于活化性能良好、成本低且绿色环保,已广泛应用于活化过硫酸盐(PS)去除水中难降解有机污染物.不同的改性修饰方法可以丰富BC表面活性位点,进一步增强BC的理化性质,提高活化性能与稳定性.首先,综述了BC应用于活化PS的改性方法;其次,总结了BC活化PS的反应活性位点,PS活化的自由基与非自由基途径及其差异;接着,分析了改性以及生物质原料对两种不同活化途径之间的转化影响;最后,展望了BC活化PS应用及机理研究的发展方向.     

离子热碳化制备Fe/N共掺杂生物炭及其催化性能研究

以铁基离子液体[BMIm]FeCl₄和木质纤维类生物质废弃物为前驱体,采用离子热碳化方法制得铁/氮共掺杂生物炭（Fe-N/BC）催化剂,并对其性质进行了表征。研究了Fe-N/BC催化剂活化过一硫酸盐（PMS）处理有机污染物罗丹明B和双酚A的性能,并对Fe-N/BC催化剂进行了吸附实验、催化动力学实验和自由基淬灭实验。结果表明,Fe-N/BC为包覆有铁金属纳米颗粒的氮掺杂石墨化碳材料,空泡结构和发达的孔隙结构使其具有很强的吸附性能,60 min后才达到吸附平衡,吸附50%的双酚A;加入氧化剂过一硫酸盐后,30 min后对双酚A的降解率达到95.5%,远远快于氮掺杂生物炭（N/BC）材料和生物炭（BC）。Fe-N/BC活化PMS降解双酚A过程中对pH不敏感,反应方式主要通过非自由基路径实现。     

改性沼渣生物炭活化过硫酸盐去除加替沙星研究

为探究生物炭（BC）活化过硫酸氢钾（PMS）去除加替沙星（GAT）的机制,本实验以厨余沼渣为原料,制备沼渣生物炭,并进行改性处理得到钴炭复合材料（Co-BC）。探索了Co-BC活化PMS降解GAT的机理,研究了催化剂投加量、PMS溶液浓度、初始pH和反应温度对GAT去除率的影响,同时探究了Co-BC活化PMS的反应机制及其作为催化剂的可再生性。结果表明,改性后生物炭的孔隙结构得到改善,Co元素以CoO晶体形式存在于材料表面,且含有丰富羧基羟基等含氧官能团;Co-BC活化PMS体系对GAT的降解效果最佳,材料投加量和PMS浓度越大反应速率越快,高温碱性条件有利于反应进行;Co-BC活化PMS体系过程中存在自由基和非自由基两种机制协同降解机制;所制备的材料具备良好的再生性能,研究结论为水体中GAT的污染治理提供了新的思路。     

铁基生物炭活化过硫酸盐处理有机废水的研究进展

环境中富集的各种有机污染物对生态系统和人体健康存在较大威胁。近年来，基于过硫酸盐（PS）的高级氧化技术（AOPs）因操作简单、成本较低且氧化还原能力强，在高效降解有机污染物方面展现出巨大潜力。铁基生物炭（Fe-biochar）由于具有吸附和催化的双重优势，在活化PS降解有机污染物领域得到了广泛应用。简述了Febiochar复合材料的制备方法，介绍了Fe-biochar活化PS过程的影响因素，分析了污染物降解过程中存在的反应机制。Fe-biochar不仅可以通过吸附作用去除污染物，还可以通过高效的电子转移来介导Fe-biochar/PS体系中自由基途径和非自由基途径对污染物进行降解。同时，对Fe-biochar的重复利用性和稳定性进行了讨论，提出了几种Fe-biochar高效再生的方法。最后对Fe-biochar用于活化PS降解有机污染物的实际应用进行了展望，以期为难降解有机污染物处理及生物质高值化利用提供参考。     

玉米秸秆生物炭活化过硫酸盐催化降解罗丹明B的性能研究

以玉米秸秆为原料，制备了不同温度的生物炭材料，以罗丹明B(RB)为目标有机污染物，研究了过硫酸盐种类和浓度、生物炭热解温度、RB浓度以及小分子酸等对生物炭活化过硫酸盐降解RB性能的影响，并开展了模拟水样中RB的降解实验。结果表明：生物炭能够有效活化过一硫酸盐（PMS）和过二硫酸盐（PDS），进而促进RB的降解，其中生物炭-PMS体系的催化活性更强；热解温度影响生物炭活化PMS的催化活性，较低热解温度制备生物炭的催化性能更好；生物炭-PMS体系的催化活性随着PMS浓度的增加或RB浓度的降低而增加；3种小分子酸（柠檬酸、抗坏血酸、草酸）能显著促进体系的催化能力；RB的初始浓度与初始降解速率符合Langmuir-Hinshelwood动力学模型，说明在RB降解过程中，吸附作用发挥着重要作用；生物炭-PMS体系降解人工地下水中RB的效果有所降低。     

改性生物炭吸附多环芳烃的效能研究

近年来，利用各种改性技术（物理、化学和生物）制备得到的众多改性生物炭，已大量应用于水体中多环芳烃（PAHs）的吸附去除。本课题研究，当向以PAHs-萘对大型溞最低全致死浓度LC100染毒的水体中加入改性生物炭Y(市售）后，大型溞的死亡率降低，并且改性生物炭的加入量越大，大型溞的死亡率越低，即可得到改性生物炭Y的投用量与大型溞的死亡率之间存在的剂量-效应关系，进一步地，大型溞的死亡率可作为定量表征不同改性生物炭吸附水体中PAHs-萘性能的生物评价指标。     

氮掺杂生物炭的制备与应用研究进展

生物质不仅储量丰富、分布广泛且可再生，是一种亟待高值化利用的资源。将其炭化后制备的生物炭具有良好的理化性质，常被用于吸附污染物、制作电极材料。但与活性炭相比，生物炭存在孔隙结构欠发达、表面官能团种类和数量稀少等问题，其应用受到了很大限制。通过对生物炭进行N元素掺杂改性制成N掺杂生物炭（NBC）可丰富生物炭孔隙结构和表面活性位点，提高吸附、导电和催化性能。本文综述了国内外近几年来关于NBC的制备/改性方法 （热解法、活化法、水热法、模板法和后处理法等）及其优点和局限性，梳理了各方法得到的NBC的形貌结构及表面化学特征，概括了氮掺杂对NBC的催化、吸附、电化学性能的影响及NBC在各领域的应用。以“制备-结构-性能及应用”相结合的思路，从NBC的应用角度逆向出发，思考如何通过探究N掺杂机理和优化制备方法，来充分发挥NBC在各领域中的应用价值，并对今后该领域的研究发展提出了展望。     

生物炭基材料在抗生素废水处理中的研究进展

生物炭是一种由生物质原料热解而成的稳定多孔碳材料。目前，生物炭及其碳基材料作为功能材料因其在一定程度上不仅实现了废弃物的合理资源化利用，而且兼具经济与环境效益而倍受研究者关注。本文综述了生物炭的生物质原料种类、生物炭在不同成分下（纤维素、半纤维素、木质素）的形成机制及表面特性；重点介绍了生物炭的改性技术，主要包括物理化学处理、杂原子掺杂、金属元素掺杂、多种元素共掺杂以及制备工艺的改良等，生物炭改性的目的是为了增加其比表面积、反应活性位点和官能团，改良孔隙结构和无机成分，从而提高它在修复环境污染的性能；然后综述了生物炭作为优良吸附剂或催化剂在用于抗生素废水的具体应用及其去除机理。最后指出生物炭虽被证明了具备去除水中各类抗生素的潜力，但在材料本身的优化以及工程抗生素废水应用中仍有一些需要填补的知识空白。     

改性生物炭作为磷吸附剂的应用与经济效益分析

综述了原材料、炭化温度、改性剂、pH、共存离子以及生物炭再生等因素影响改性生物炭对磷（P）吸附性能的原因，并对不同改性生物炭的吸附性能及其吸附回收磷的经济效益进行了分析，以期为新型高效磷吸附材料研发提供指导与借鉴。     

污泥生物炭催化高级氧化过程进展

作为废水处理过程的副产物,污泥的高效处理处置是环保领域的难题之一。通过高温热解将污泥转化为生物炭是一种有效的污泥资源化途径。污泥生物炭不仅可作为“吸附剂”吸附去除水体中污染物,还可作为新型“催化剂”高效催化高级氧化过程以降解水体中的有机污染物。本文综述了近些年来国内外关于污泥生物炭在高级氧化技术领域尤其是催化过硫酸盐（PS）、过氧化氢（H₂O₂）、臭氧（O₃）以及光催化等氧化过程降解有机污染物的研究进展。通过探讨污泥生物炭的表面官能团、掺杂改性杂原子、负载过渡金属及其氧化物以及与其他技术耦合催化降解有机污染物的研究现状,进一步揭示污泥生物炭催化作用的关键活性位点以及催化机理。最后提出该领域目前面临的主要问题及未来发展方向,为污泥生物炭进一步实现高附加值资源化利用提供重要参考。     

Hierarchical amphiphilic high-efficiency oil–water separation membranes from fermentation derived cellulose and recycled polystyrene

A high-efficiency separation of oil and water can be achieved by using specially designed amphiphilic porous membrane. However, the preparation of such membranes often involves complex multistep chemical processes. Herein, we report an amphiphilic composite membrane (polystyrene [PS]/bacterial cellulose [BC] membrane) consisting of hydrophobic recycled PS and hydrophilic BC, fabricated by a facile in situ fermentation process. Not only these membranes exhibit a combination of contrasting wettability but also comprise of a hierarchical network of microfibers and nanofibers, which makes them ideal for oil–water separation. The structural and morphological properties of as-produced BC, recycled PS membrane, and PS/BC composite membrane were studied by Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The ability of the membranes to separate oil and water was tested by using an emulsion of hexane-in-water as the feed and the collected filtrates were characterized by optical microscopy and UV–Vis spectroscopy. PS membranes were unable to separate oil and water, while the PS/BC membrane efficiently separated water from the emulsion. PS/BC composite membranes showed a high water recovery of more than 90%, against only 57% recovery shown by BC. Mechanisms of oil–water separation for each membrane are discussed. The reusability of the PS/BC composite membrane was also demonstrated.     

Co-pyrolytic behaviors of biomass and polystyrene: Kinetics,thermodynamics and evolved gas analysis

The pyrolytic degradation mechanism of chestnut shell (CNS) and its blend with waste polystyrene (PS) were investigated. Individual pyrolysis behavior of samples obtained separately was compared with those of the blends using a combined TGA/MS/FT-IR system. To elaborate kinetic analysis and to determine kinetic parameters, distributed activation energy model (DAEM) was used. The average activation energy of co-pyrolytic decomposition reaction was 191.6 kJ/mol, while the activation energy of the pyrolysis of CNS and PS was 175.2 and 208.9 kJ/mol, respectively. Friedman and Flynn-Wall-Ozawa iso-conversional methods were applied and the results were found to be consistent with the models. To express the presence of complex reaction mechanisms and the interactions of the radicals, thermodynamic parameters were also calculated. Finally, the pathways for main volatiles were established, and their relationship with the pyrolytic degradation was suggested.     

Chemical modification of polyethersulfone nanofiltration membranes: A review

Polysulfone (PS) and poly(ether)sulfone (PES) are often used for synthesis of nanofiltration membranes, due to their chemical, thermal, and mechanical stability. The disadvantage for applying PS/PES is their high hydrophobicity, which increases membrane fouling. To optimize the performance of PS/PES nanofiltration membranes, membranes can be modified. An increase in membrane hydrophilicity is a good method to improve membrane performance. This article reviews chemical (and physicochemical) modification methods applied to increase the hydrophilicity of PS/PES nanofiltration membranes. Modification of poly(ether)sulfone membranes in view of increasing hydrophilicity can be carried out in several ways. Physical or chemical membrane modification processes after formation of the membrane create more hydrophilic surfaces. Such modification processes are (1) graft polymerization that chemically attaches hydrophilic monomers to the membrane surface; (2) plasma treatment, that introduces different functional groups to the membrane surface; and (3) physical preadsorption of hydrophilic components to the membrane surface. Surfactant modification, self‐assembly of hydrophilic nanoparticles and membrane nitrification are also such membrane modification processes. Another approach is based on modification of polymers before membrane formation. This bulk modification implies the modification of membrane materials before membrane synthesis of the incorporation of hydrophilic additives in the membrane matrix during membrane synthesis. Sulfonation, carboxylation, and nitration are such techniques. To conclude, polymer blending also results in membranes with improved surface characteristics. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

活化过硫酸盐氧化法降解酚类污染物的研究进展

活化过硫酸盐氧化法因具有经济、高效、环保、安全稳定等优势,近年来在酚类污染物的降解中备受关注。目前活化过硫酸盐降解酚类污染物的方法主要包含外加能量活化和外加催化剂活化两大类。其中单一的热活化、光活化、超声活化、电化学活化、等离子体活化等外加能量活化过程能量消耗较大,且对酚类污染物不易达到满意的降解效果。过渡金属活化和碳质材料活化等外加催化剂活化方式,由于环境污染小、操作成本低、降解率高等优点,越来越受到科研工作者的重视。为了提高对酚类污染物的降解率,不同的过硫酸盐活化方式不断融合,逐渐形成多种耦合活化方式,例如,碳质材料与过渡金属的耦合活化、电化学与过渡金属催化剂的耦合活化以及光与外加催化剂的耦合活化等。本文论述了活化过硫酸盐氧化法降解酚类污染物的研究进展,概述了活化过硫酸盐的影响因素,分析了活化过硫酸盐降解酚类污染物存在的问题,展望了活化过硫酸盐降解酚类污染物的发展方向。     

Hemostatic activities of nano/microporous bilayer dressings in a femoral artery bleeding rat model

Recently, an effective hemostatic dressing requirement has become a major problem in both the military and civilian world. Available hemostatic agents are too expensive, ineffective, unsafe, or complicated to use. Here, we evaluated the hemostatic efficacy of a nano/micro bilayer hemostatic dressing including a porous sublayer from chitosan (CTS) and bacterial cellulose (BC) and a nanofibrillar upper layer from silk fibroin (SF). In addition, several active agents rolled in coagulation cascade [vitamin K (Vit K), protamine sulfate (PS), kaolin (Kao), etc.] were doped to the sublayer of bilayer hemostatic agent and their activities were compared via in vivo and in vitro tests. Lactate dehydrogenase (LDH) activity test results demonstrated that BC/CTS, SF‐coated BC/CTS, and Vit K K/BC/CTS, SF/phosphatidylcholine (PC)‐coated BC/CTS showed higher LDH activity compared to standard gauze (p < 0.005). In a femoral artery bleeding rat model, SF‐coated PS/BC/CTS significantly reduced bleeding time (80 ± 0.3 s) compared to standard gauze and kaolin‐doped group (p < 0.005). Blood loss and mortality rate with 2.3 g and 37.5% SF‐coated BC/CTS and SF‐coated PS/BC/CTS showed increased efficacy in achieving hemostasis compared to standard gauze. All the prepared hemostatic dressings except for kaolin‐doped BC/CTS and standard gauze induced no inflammatory reaction in the tissue. All these data suggest that active agent‐doped BC/CTS/SF‐based bilayer hemostatic dressings have a great influence on the resulting hemostatic action. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43657.     

Synthesis of Al3BC in air from mechanically activated Al/B/C powder mixtures

A ternary aluminum borocarbide, Al₃BC was prepared for the first time by self-propagating high-temperature synthesis (SHS) induced by mechanical activation of Al/B/C powder mixtures in air. The effect of mixing molar ratio of Al/B/C and grinding time on the formation of Al₃BC was investigated. On the other hand, Al₃BC was also formed by mechanical activation and subsequent annealing of Al/B/C=3/1/1 powder mixture. The lattice constants of Al₃BC obtained in two methods were compared.     

Instability of styrene/polystyrene/polybutadiene/polystyrene‐b‐polybutadiene emulsions that emulate styrene polymerization in the presence of polybutadiene

This article investigates the room temperature demixing of oil‐in‐oil emulsions containing styrene (St), polybutadiene (PB), a St‐butadiene star block copolymer (BC), and two polystyrene (PS) samples of different molecular weights and is a contribution toward a better understanding of the stability/instability of the reaction mixture in a bulk high‐impact polystyrene (HIPS) process close to the phase inversion. Twelve bulk prepolymerizations of St in the presence of PB were emulated, at 10%, 15%, and 20% conversion; and with constant grafting efficiencies. All the blends contained 6% in weight of butadiene units. After stirring the blends for 24 h, the decantation demixing process was monitored along 30 days, with daily measurement of the interface levels after appearance of a clear interface. For some of the isolated phases, their unswollen morphologies were observed by transmission electron microscopy. All the isolated phases exhibited macrophase separation into homopolymer‐ and copolymer‐rich macrodomains with lamellar microdomains. The BC showed a greater affinity toward the PS‐rich phase. The separation of an independent BC‐rich phase in the blends containing the high molar mass PS and at high grafting efficiencies, modifies the idea of the graft‐ or BC molecules located at the interface of large PS‐rich and PB‐rich phases. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers     

高抗冲聚苯乙烯改性的发展趋势

综述了聚苯乙烯 (PS)的发展历史 ,高抗冲聚苯乙烯 (HIPS)的工业生产方法和HIPS改性的发展趋势。指出HIPS的前途在于改善它的光泽、耐应力开裂、阻燃、耐热等性能。我国PS改性应加强基础理论研究 ,加大新设备与新工艺的研究开发 ,立足于现有的生产装置进行在线改性 ,提高市场的竞争能力     

Ni掺杂对介孔硅结构和性能的影响

用直接水热合成法(DHT)、模板剂离子置换法(TIE)及焙烧后的介孔MCM-41后处理法(PS)合成了N i掺杂的纳米介孔MCM-41。研究了用这3种方法进行N i掺杂对纳米介孔材料形貌、结构和性能的影响。TEM和XRD结果表明,采用后处理法将N i引入,不影响纳米介孔颗粒的分散性和形貌,并且PS20〔PS法合成,n(S i)/n(N i)=20〕中没有N i的氧化物形成。随着N i的引入,PS20的比表面由MCM-41的757 m2/g下降为545m2/g,孔径和孔容分别由3.2 nm和0.75 cm3/g增大为4.3 nm和0.86 cm3/g。     

大分子溴系复合阻燃剂对PS和发泡PS的阻燃改性

将大分子溴系阻燃剂(FR–122P)与溴化环氧树脂(2200HM)组成的复合阻燃剂应用于聚苯乙烯(PS)复合材料和发泡PS中,研究了复合阻燃剂的配比和含量对PS复合材料阻燃性能以及复合阻燃剂含量对发泡PS泡孔结构和阻燃性能的影响,采用热重分析、扫描电子显微镜观察、极限氧指数(LOI)测试、垂直燃烧(UL–94)和水平燃烧试验等手段进行了表征。结果表明,当FR–122P与2200HM质量比为4∶1、总添加量为25%时,PS复合材料的LOI可达25.8%,并可通过UL–94 V–0等级;当复合阻燃剂的添加量为40%时,可得到泡孔尺寸较小、泡孔密度较大、膨胀倍率较高的发泡PS复合材料,且其可通过泡沫水平燃烧的HF–2等级。大分子溴系阻燃剂与溴化环氧树脂的复合阻燃剂对PS和发泡PS复合材料具有较好的阻燃效果。