Carbonated ferric green rust as a new material for efficient phosphate removal

Novel TiO(2)/carbon nanocomposites were prepared through the pyrolysis of TiO(2)/poly(furfuryl alcohol) hybrid materials, which were obtained by the sol-gel method, starting from titanium tetraisopropoxide (TTIP) and furfuryl alcohol (FA) precursors. Six different TiO(2)/C samples were prepared based on different TiO(2) nanoparticle sizes and TiO(2)/FA ratios. All of the samples were characterized using X-ray diffraction, infrared, and Raman spectroscopy. The results indicated effective FA polymerization onto the TiO(2) (anatase) nanoparticles, polymer conversion to disordered carbon following the pyrolysis, and a simultaneous TiO(2) anatase-rutile phase transition. The resulting TiO(2)/carbon composites were used as photocatalysts in the advanced oxidative process (AOP) for the degradation of reactive organic dyes in aqueous solution. The results indicate excellent photocatalytic performance (degradation of 99% of the dye after 60 min) with several advantages over traditional TiO(2)-based photocatalysts.     

A systematically generated, pressure-dependent mechanism for high-conversion ethane pyrolysis. 1. Pathways to the minor products

The deposition of carbon during hydrocarbon pyrolysis is part of many industrial processes. The rate and nature of deposition depend, in part, on the gas-phase chemistry of the minor pyrolysis products, which serve as deposition precursors. But the specific reaction pathways governing the formation and destruction of these minor gas-phase products are only partially known. We apply an updated version of our automated mechanism generation tool XMG-PDep to the high-conversion, pyrocarbon-depositing ethane pyrolysis system of Glasier and Pacey, to systematically uncover the likely reaction pathways governing the observed minor products acetylene, propylene, 1,3-butadiene, and benzene. Thorough examination by means of sensitivity, equilibrium, and reaction-pathway analyses reveals an extremely complex, intertwined set of reaction pathways controlling these deposition precursors, some of which are not often considered in the wider pyrolysis literature. Large, aggregated sets of disproportionation reactions, for example, appear to play an important role in the formation of benzene. The analyses motivate a companion paper (following paper in this issue) which explores in greater depth the effects of large groups of radical disproportionation reactions, omitted reaction families, and the possibility that pressure changes in the reactor could alter the distribution of the deposition precursors.     

Template Synthesis of Polyacrylonitrile‐Based Ordered Macroporous Materials and Their Derivatives

Ordered macroporous polyacrylonitrile (mPAN) materials with 10¹–10³ nm pore diameter were prepared by radical polymerization using colloidal silica as a template followed by removal of the template. Both ordered macroporous carbon and hydrogels were derived from mPAN by means of pyrolysis and alkaline hydrolysis, respectively, whose morphology and composition were characterized experimentally.     

快速热解炭负载Cu-Zn对碱木质素热裂解生成单酚类化合物的催化性能

以具备丰富中孔和大孔结构的快速热解炭(FPC)为载体,采用共浸渍法制备了不同Cu/Zn摩尔比的CuxZny/FPC负载型催化剂.采用X射线衍射仪(XRD)、高分辨场发射扫描电子显微镜(FE-SEM)及电子能谱仪(EDX)对催化剂进行了表征,采用热重分析仪(TG)和热解气质联用仪(Py-GC/MS)评价了催化剂对碱木质素热裂解生成单酚类化合物的催化性能.结果表明,催化剂活性组分Cu O和Zn O晶相结构均一,很好地嵌入到FPC中孔和大孔结构中,未发生聚集状态或生成Cu Zn合金;随着Cu或Zn金属负载量的增大,相应的Cu或Zn金属氧化物衍射峰强度逐渐增强,平均晶粒尺寸逐渐增大.热重分析结果表明,催化剂降低了碱木质素热裂解残炭率和反应活化能,提高了热裂解反应效率.热解气质联用分析表明,CuxZny/FPC催化剂大幅度简化了碱木质素热裂解单酚类化合物种类(从23种减少到了10种),Cu0.67Zn0.33/FPC对单酚类化合物表现出最大的选择性(52.99%),与Cu/FPC相比选择性增加49.7%.     

热解蔗糖/γ-氧化铝制备碳均匀覆盖的碳/氧化铝复合材料

碳/氧化铝复合材料（CCA）作为催化剂载体或吸附剂具有广泛用途.在文献报道中,大部分的碳-氧化铝复合材料是通过热解气相碳氢化合物制得的,这样在氧化铝表面覆盖的碳通常是不均匀的.本文提出了一个操作简便,且重复性高的新方法来制备碳均匀覆盖的碳/氧化铝复合材料——热解均匀分散在氧化铝表面的蔗糖.在这种复合材料中,碳层厚度可控制为一个石墨单层的厚度,且碳的覆盖度及层数可以通过改变浸渍的蔗糖量及浸渍次数来进行调控.     

Facile and one-step preparation carbon quantum dots from biomass residue and their applications as efficient surfactants

Using biomass residue as a source of carbon precursors, a pyrolysis method was used to prepare biomass-derived luminescent Carbon Quantum Dots (CQDs). The prepared CQDs exhibited excellent fluorescence and luminescence properties and fluorescence behaviors of CQDs acquired at different pyrolysis temperatures varied. Importantly, the CQDs showed superior surface activity and the styrene-in-water Pickering emulsion prepared using the CQDs as nano-sized surfactant was highly stable: the higher the pyrolysis temperature the better the stability of the emulsion. In addition, there was no stratification found in the emulsion which was stabilized by the CQD500 (CQDs prepared at 500?°C) after holding for 72?hours. This research provided an approach for preparing the surfactants of nano-sized particles in large scale. The CQDs prepared using the proposed methods are expected to have a high number of potential applications.     

含铁煤热解过程中HCN形成的主要影响因素

煤中矿物质和外加含铁化合物对氮氧化物主要前驱体之一HCN在热解过程中的释放具有重要的作用。使用固定床反应器进行了程序升温过程中Ar气氛下的神东、平朔和常村原煤以及相应的脱灰煤、浸渍法加铁煤和沉淀法加铁煤的热解实验，重点研究了HCN释放的影响因素。实验结果表明，煤中的矿物质和外加铁对HCN释放的作用较大程度上取决于煤的变质程度，变质程度越低的煤影响越明显；矿物质和含铁化合物的作用主要出现在升温时挥发分释放的过程，并且因添加方式不同以及煤种不同而对HCN的形成与释放具有不同的作用规律；沉淀法添加的铁在变质程度较低的煤中分散效果较好，对HCN生成量的减少作用明显。同时热解反应温度、煤样粒度和恒温阶段停留时间的长短对HCN释放也有影响。     

Synthesis of Nitrogen-doped Carbon Supported Cerium Single Atom Catalyst by Ball Milling for Selective Oxidation of Ethylbenzene

Through screening Ce precursors and pyrolysis temperatures[Ce(acac)₃ as Ce precursors and pyrolysis at 900 °C], zeolitic imidazolate framework-8(ZIF-8) derived nitrogen-doped carbon supported cerium single atom catalyst(Ce₁/NC) is successfully prepared by ball milling method. The Ce₁/NC catalyst exhibits exceptional catalytic performance in the selective oxidation of saturated C―H bonds in aromatic compounds, e.g., 91% conversion and 99% selelctivity can be achieved in the oxidation of ethylbenzene to acetophenone under mild reaction conditions.     

Fabrication of carbon nanofiber by pyrolysis of freeze-dried cellulose nanofiber

The possibility of fabricating carbon nanofibers from cellulose nanofibers was investigated. Cellulose nanofiber of ~50 nm in diameter was produced using ball milling in an eco-friendly manner. The effect of the drying techniques of cellulose nanofibers on the morphology of carbon residue was studied. After pyrolysis of freeze-dried cellulose nanofibers below 600 °C, amorphous carbon fibers of ~20 nm in diameter were obtained. The pyrolysis of oven-dried precursors resulted in the loss of original fibrous structures. The different results arising from the two drying techniques are attributed to the difference in the spatial distance between cellulose nanofiber precursors.     

Fabrication of functional hollow carbon spheres with large hollow interior as active colloidal catalysts

In this study,we have established a facile method to synthesize functional hollow carbon spheres with large hollow interior,which can act as active colloidal catalysts.The method includes the following steps:first,hollow polymer spheres with large hollow interior were prepared using sodium oleate as the hollow core generator,and 2,4-dihydroxybenzoic acid and hexamethylene tetramine(HMT) as the polymer precursors under hydrothermal conditions;Fe 3+ or Ag + cations were then introduced into the as-prepared hollow polymer spheres through the carboxyl groups;finally,the hollow polymer spheres can be pseudomorphically converted to hollow carbon spheres during pyrolysis process,meanwhile iron or silver nanoparticles can also be formed in the carbon shell simultaneously.The structures of the obtained functional hollow carbon spheres were characterized by TEM,XRD,and TG.As an example,Ag-doped hollow carbon spheres were used as colloid catalysts which showed high catalytic activity in 4-nitrophenol reduction reaction.     

Wood‐Derived Ultrathin Carbon Nanofiber Aerogels

Carbon aerogels with 3D networks of interconnected nanometer‐sized particles exhibit fascinating physical properties and show great application potential. Efficient and sustainable methods are required to produce high‐performance carbon aerogels on a large scale to boost their practical applications. An economical and sustainable method is now developed for the synthesis of ultrathin carbon nanofiber (CNF) aerogels from the wood‐based nanofibrillated cellulose (NFC) aerogels via a catalytic pyrolysis process, which guarantees high carbon residual and well maintenance of the nanofibrous morphology during thermal decomposition of the NFC aerogels. The wood‐derived CNF aerogels exhibit excellent electrical conductivity, a large surface area, and potential as a binder‐free electrode material for supercapacitors. The results suggest great promise in developing new families of carbon aerogels based on the controlled pyrolysis of economical and sustainable nanostructured precursors.     

Carbon and SiC macroscopic beads from ion-exchange resin templates

A method for preparing carbon and SiC macroscopic beads using ion-exchange resins as a macrotemplate that determines the macroshape and the pore structure of the product materials is reported. First, silicates are ion-exchanged into the resins to prevent the resin from collapsing during subsequent carbonization and allow them to be used as precursors for SiC formation. SiC is prepared via carbothermal reduction of carbon/silica composite beads obtained upon carbonization of the resin/silicate in an inert atmosphere. Finally, silica is removed by HF etching. Very high-surface area (1670-2026 m2 g-1) micro- or micro-/mesoporous carbon beads and relatively high-surface area (35-63 m2 g-1) macro- and meso-/macroporous SiC beads were prepared by the described method. The pore structure and the macroshape of the particles were controlled by the type of ion-exchange resins employed, gel or macroreticular.     

Hierarchically porous carbon membranes derived from PAN and their selective adsorption of organic dyes

Porous carbon membranes were favorably fabricated through the pyrolysis of polyacrylonitrile(PAN) precursors, which were prepared with a template-free technique-thermally induced phase separation. These carbon membranes possess hierarchical pores, including cellular macropores across the whole membranes and much small pores in the matrix as well as on the pore walls. Nitrogen adsorption indicates micropores(1.47 and 1.84 nm) and mesopores(2.21 nm) exist inside the carbon membranes, resulting in their specific surface area as large as 1062 m2/g. The carbon membranes were used to adsorb organic dyes(methyl orange, Congo red, and rhodamine B) from aqueous solutions based on their advantages of hierarchical pore structures and large specific surface area. It is particularly noteworthy that the membranes present a selective adsorption towards methyl orange, whose molecular size(1.2 nm) is smaller than those of Congo red(2.3 nm) and rhodamine B(1.8 nm). This attractive result can be attributed to the steric structure matching between the molecular size and the pore size, rather than electrostatic attraction. Furthermore, the used carbon membranes can be easily regenerated by hydrochloric acid, and their recovery adsorption ratio maintains above 90% even in the third cycle. This work may provide a new route for carbon-based adsorbents with hierarchical pores via a template-free approach, which could be promisingly applied to selectively remove dye contaminants in aqueous effluents.     

Highly fluorescent carbon dots from peanut shells as potential probes for copper ion: The optimization and analysis of the synthetic process

The use of natural materials, a renewable resource, instead of chemicals as carbon precursors for simple synthesis of fluorescent carbon dots (FCDs) remains a significant challenge. Here, we report the preparation of FCDs with a photoluminescence (PL) quantum yield (QY) of 10.58% from peanut shells via one-pot pyrolysis treatment optimized by using a central composite experiment design. Optimum pyrolysis conditions were found to be 400 °C temperature, 4 h duration, and 70 g peanut shell weight. The as-prepared FCDs possess unique excitation-dependent behavior, good water dispersibility and high photostability. The results of Fourier transform infrared (FTIR) spectroscopy to analyze the pyrolytic process indicated the complete combustion of peanut shells happened at 3 and 4 h at 400 °C. The PL intensity of the FCDs was not always proportional to the corresponding QY value in our work due to the different amount of carbon-rich residues after the pyrolysis process. Fluorescence-quenching trials were conducted to analyze their sensitivity and selectivity in Cu²⁺ detection. The detection limit was found to be 4.8 μM. Our pyrolysis treatment of peanut shells for preparing FCDs is not only a green and facile method but also a means of recycling peanut shells.     

In-situ incorporation of gold nanoparticles of desired sizes into three-dimensional macroporous matrixes

We present here a facile route to the incorporation of gold nanoparticles (GNPs) with desired sizes into three-dimensionally ordered macroporous (3DOM) matrixes. Our route combined the first attachment of small GNPs to the silica colloidal crystal templates as precursors and their subsequent controlled growth by the in-situ chemical reduction method. The desired enlargement of GNPs was acquired via their alternating and repeated exposure to solutions of auric salts and reducing agent NH(3)OH. Such gold-decorated silica templates were also converted into self-sustained polystyrene (PS) macroporous films with GNPs embedded in their wall structures. The growth of gold seeds can be easily followed by their UV-vis absorbance spectra. The route provides an alternative way to incorporate GNPs with predetermined sizes into 3DOM matrixes without destroying their ordered structures. A highlight of our approach is that it obviates the need for the preformation of various-sized GNPs, which is an indispensable step in many other approaches.     

Bio-oil production by flash pyrolysis of sugarcane residues and post treatments of the aqueous phase

The pyrolysis of three sugarcane residues (internal bagasse, external and whole plant) has been carried out in a pilot bubbling fluidized bed pyrolyzer operating under a range of temperature from 300 °C to 600 °C and two vapor residence time (2 and 5 s), with the aim of determining their pyrolysis behavior including products yields and heat balance. The composition of the product gases was determined, from which their heating value was calculated. The liquid bio-oil was recovered with cyclonic condensers and separated into two phases, an aqueous phase and an organic phase. The energy content of the organic phase was determined in comparison with common fossil fuels. Activated carbon adsorption and distillation at 110 °C were used to treat the aqueous phase, with the aim of recovering valuable hydrocarbons and purifying the aqueous phase for wastewater disposal. Furthermore, the thermal sustainability of the pyrolysis process was estimated by considering the energy contribution of the product gases and of the liquid bio-oil in relation to the pyrolysis heat requirements. The optimum pyrolysis temperatures were identified in terms of maximizing the liquid yield, maximizing the energy from the product bio-oil, and maximizing the net energy from the product bio-oil after ensuring a self-sustainable process by utilizing the product gases and part of bio-oil as heat sources.     

Influence of substrate stiffness on cell-substrate interfacial adhesion and spreading: a mechano-chemical coupling model

Highly ordered three dimensionally macroporous carbon spheres (3DMPCS) were successfully prepared against removable colloidal silica crystal bead templates by carbonization of glucose. The unique structural characteristics of the well-developed three dimensionally interconnected macropores were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and nitrogen adsorption. The 3DMPCS have uniform large pore structures with size about 250 nm. Pt nanoparticles were supported on the macroporous carbon spheres by two aqueous impregnation methods, and it was found that the 3DMPCS supported Pt exhibited high electrocatalytic activity for methanol oxidation.     

Diacetylenes with Ionic‐Liquid‐Like Substituents: Associating a Polymerizing Cation with a Polymerizing Anion in a Single Precursor for the Synthesis of N‐Doped Carbon Materials

Imidazolium‐ and benzimidazolium‐substituted diacetylenes with bromide or nitrogen‐rich dicyanamide and tricyanomethanide anions were synthesized and used as precursors for the preparation of N‐doped carbon materials. On pyrolysis under argon at 800 °C both halide precursors afforded graphite‐like structures with nitrogen contents of about 8.5 %. When the dicyanamide and tricyanomethanide precursors were thermolyzed at the same temperature, graphite‐like structures were obtained that exhibit nitrogen contents in the range 17–20 wt %; thereby, the benefit of associating a polymerizing cation with a polymerizing anion in a single precursor was demonstrated. On pyrolysis at 1100 °C the nitrogen contents of the latter pyrolysates remain high (ca. 6 wt %). Adsorption measurements with krypton at 77 K indicated that the materials are nonporous. The highest electrical conductivity was observed for a pyrolysate with one of the lowest nitrogen contents, which also has the highest degree of graphitization. Thus, the quest for N‐rich carbons with high electrical conductivities should include both maximization of the nitrogen content and optimization of the degree of graphitization. Crystallographic investigation of the precursors and spectroscopic characterization of the pyrolysates prepared by heating at 220 °C indicate that construction of the final carbon framework does not involve the intermediate formation of a polydiacetylene.     

催化裂解CH4制备不同形貌的碳纳米管

通过甲烷于较低温度(500～700℃)下在镍催化剂上催化裂解制备了各种形貌的碳纳米管.透射电镜测试结果表明,碳纳米管的外径和内径明显地受催化剂的大小和形貌的影响.本文考察了催化剂前驱体的种类、反应温度和原料气流速对镍催化剂和碳纳米管形貌的影响.     

基于柠檬酸的石墨烯量子点的制备及其应用

石墨烯量子点（GQDs）是一种新型碳基准零维材料,不但具有石墨烯的独特平面结构,同时具备碳点的量子限制效应和边界效应。GQDs具有独特的光学性质、低毒性、高荧光稳定性和高生物相容性,被广泛应用于检测、传感、催化、细胞成像、药物递送和污染治理等领域。GQDs的合成分为自上而下法和自下而上法,前者将大尺寸的石墨烯、石墨、碳材料切割成纳米级的量子点,后者使用不同的前驱体,通过水热法、热裂解法等方法合成石墨烯量子点。柠檬酸（CA）是一种重要的有机酸,室温下是白色结晶状粉末,是自下而上法合成GQDs的一种常用前驱体,近年来有许多关于以CA为前驱体合成不同GQDs的研究,以CA为前驱体合成的GQDs（CA-GQDs）在生物医药、荧光检测、成像等领域均有应用,具有较好的应用前景。对近年来基于CA的合成方法和具体应用进行了总结和回顾,旨在将现有CA-GQDs的相关成果尽可能汇总和展现,以对相关领域研究工作者提供一定参考,并对未来CA-GQDs较有前景的研究方向进行了展望。