The Analysis of Pore Development and Formation of Surface Functional Groups in Bamboo-Based Activated Carbon during CO2 Activation

Pore development and the formation of oxygen functional groups were studied for activated carbon prepared from bamboo (Bambusa bambos) using a two-step activation with CO₂, as functions of carbonization temperature and activation conditions (time and temperature). Results show that activated carbon produced from bamboo contains mostly micropores in the pore size range of 0.65 to 1.4 nm. All porous properties of activated carbons increased with the increase in the activation temperature over the range from 850 to 950 °C, but decreased in the temperature range of 950 to 1000 °C, due principally to the merging of neighboring pores. The increase in the activation time also increased the porous properties linearly from 60 to 90 min, which then dropped from 90 to 120 min. It was found that the carbonization temperature played an important role in determining the number and distribution of active sites for CO₂ gasification during the activation process. Empirical equations were proposed to conveniently predict all important porous properties of the prepared activated carbons in terms of carbonization temperature and activation conditions. Oxygen functional groups formed during the carbonization and activation steps of activated carbon synthesis and their contents were dependent on the preparation conditions employed. Using Boehm’s titration technique, only phenolic and carboxylic groups were detected for the acid functional groups in both the chars and activated carbons in varying amounts. Empirical correlations were also developed to estimate the total contents of the acid and basic groups in activated carbons in terms of the carbonization temperature, activation time and temperature.     

双离子液体基多孔炭的制备与电化学性能

以质子型离子液体1-氢-3-乙烯基咪唑硫酸氢盐(HVIm HSO₄)为主炭源,以1-丁基-3-甲基咪唑六氟磷酸盐(BMImPF₆)为助剂,在氮气气氛、1000℃下一步炭化得到氮、磷、硫共掺杂多孔炭.通过N₂吸附-脱附、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、拉曼光谱(Raman)、热重分析(TGA)和X射线光电子能谱(XPS)等技术对多孔炭进行了分析表征.结果表明,多孔炭的孔结构以微孔为主,最高比表面积可达1111 m²/g,其微晶结构中无定形碳和石墨化碳并存;多孔炭中的氮主要以季氮(N-Q)、吡咯氮(N-5)和吡啶氮(N-6)的形式存在,磷以磷-氧(N—O—P)键合形式为主,硫主要以噻吩硫(C—S—C)为主.在6 mol/L KOH溶液、三电极体系中,多孔炭在0. 5 A/g电流密度下的比电容为138 F/g;在10 A/g电流密度下的比电容为100 F/g;在2 A/g电流密度下循环充放电10000次,其比电容保持率为95. 8%,显示出良好的电化学性能.     

四氯化碳与二甲基亚砜制备新型碳材料

报道了在固体KOH及相转移催化剂作用下 ,四氯化碳与二甲基亚砜 (DMSO)发生一种新颖碳化反应 ,生成棕色的富碳材料 .该富碳材料在 70 0℃下加热分解 ,提纯后得到直径为 30～ 80nm的多孔碳粒子 .该碳材料比表面积为 4 30m2 ·g-1,平均孔径为 2 .6× 10 -9m ,其结构中同时含有sp2 与sp3 杂化的碳原子     

Nitrogen and phosphorus co-doped carbocatalyst for efficient organic pollutant removal through persulfate-based advanced oxidation processes

Carbocatalysts doped with heteroatoms such as nitrogen or sulphur have been reported to be useful in persulfate-based advanced oxidation processes for organic pollutant removal. However, there is limited research on the effect of doping with phosphorus atoms on degradation performance. In this work, a new nitrogen and phosphorus-doped carbocatalyst (N, P-HC) was designed using hydrothermal carbonization followed by pyrolysis at 700 °C, with olive pomace as a carbon source, to degrade organic pollutants in the presence of peroxydisulfate (PDS). Experimental results showed that N, P-HC, with its large specific surface area (871.73 m².g⁻¹), high content of N-pyridinic and N-pyrrolic groups, and the presence of P-O-C and O-P-C bonds, exhibited high degradation performance (98% degradation of Rhodamine B (RhB) in 40 min, with an apparent rate constant (k_app) of 0.055 min⁻¹ and an excellent turnover frequency (TOF) of 0.275 min⁻¹). Quenching study and EPR analysis revealed that singlet oxygen generation (¹O₂) and direct electron transfer were the main reaction pathways for the non-radical pathway in the degradation of RhB. The improved catalytic efficiency in the N, P-HC/PDS/RhB system can be attributed to the synergistic effect between N and P atoms in the graphitic structure of the carbocatalyst, its high surface area, and the presence of oxygenated functional groups on the surface of the N, P-HC. The used N, P-HC carbocatalyst can also be efficiently recovered by heat treatment at 500 °C. Overall, this study presents a simple and environmentally friendly method for synthesizing a high-performance N, P co-doped olive pomace-based carbocatalyst for water decontamination through PS-AOPs processes.     

Study of adsorption phenomena ongoing onto clinoptilolite with the immobilized interfaces

The development of innovative clean-up technologies remains a challenge as current procedures have many limitations, such as being expensive, concentration or pollutant specific, and many others. Natural zeolite of clinoptilolite type was beneficiated with surfactant octadecylammonium and alginate biopolymers using the sol-gel method. Carbonization process in pyrolysis chamber combusted organic waste materials and reaching the maximum temperature of 700°C was used for the surface carbonization, respectively. Resulted zeolite based products were analyzed by FTIR, TG, DTA and examined on the selected aqueous pollutants removal using the conventional laboratory adsorption experiments. The ability of ODA and alginate linked zeolite of clinoptilolite type to form complexes with anions (such as nitrate, sulphate, chloride and phosphate) and to remove them from contaminated waters was validated. Carbon deposition onto clinoptilolite surface originated from the pyrolytic carbon-rich waste combustion simulated the new zeolite based hybrid to active coke, adsorption efficiency of which towards phenol was approved. Thermogravimetric analyses of the advanced zeolite-based adsorbents were accomplished to find out how temperature resistant are the novel zeolite based materials in respect to the original, untreated one. While the native clinoptilolite indicated according to DTA analysis one broad endothermic response around 100–130°C, resulted from the loss of adsorbed water, by the ODA-modified clinoptilolite was except this DTA peak, the broad exothermic response started from 370 up to 560°C observed. This DTA profile is assumed to record a slowly breakdown of attached ODA surfactant and sequential loss of mass due to continual heating of sample under elevated temperature.     

A Molecular Pillar Approach To Grow Vertical Covalent Organic Framework Nanosheets on Graphene: Hybrid Materials for Energy Storage

Hybrid 2D–2D materials composed of perpendicularly oriented covalent organic frameworks (COFs) and graphene were prepared and tested for energy storage applications. Diboronic acid molecules covalently attached to graphene oxide (GO) were used as nucleation sites for directing vertical growth of COF‐1 nanosheets (v‐COF‐GO). The hybrid material has a forest of COF‐1 nanosheets with a thickness of 3 to 15 nm in edge‐on orientation relative to GO. The reaction performed without molecular pillars resulted in uncontrollable growth of thick COF‐1 platelets parallel to the surface of GO. The v‐COF‐GO was converted into a conductive carbon material preserving the nanostructure of precursor with ultrathin porous carbon nanosheets grafted to graphene in edge‐on orientation. It was demonstrated as a high‐performance electrode material for supercapacitors. The molecular pillar approach can be used for preparation of many other 2D‐2D materials with control of their relative orientation.     

焦磷酸钠对液相碳化法制备纳米碳酸钙形貌的影响

利用液相碳化法制备了不同形态的纳米碳酸钙颗粒，用TEM、XRD和IR等手段分析表征了纳米碳酸钙的形态和结构，研究了焦磷酸钠对液相碳化法制备纳米碳酸钙合成过程及颗粒形态结构的影响规律。结果表明反应温度是影响纳米碳酸钙形态的关键因素，温度升高时纳米碳酸钙由立方形转变为纺锤形。焦磷酸钠能够促进碳酸钙的晶体成核，抑制晶体生长，在碳化温度大30 ℃时生成链状和棒状的纳米碳酸钙。另外，还分析了链状和棒状纳米碳酸钙的形成机理。     

Structure and plasmonic properties of thin PMMA layers with ion‐synthesized Ag nanoparticles

Silver nanoparticles are synthesized in polymethylmethacrylate by 30 keV Ag⁺ ion implantation with high fluences. The implantation is accompanied by structural and compositional evolution of the polymer as well as sputtering. The latter causes towering of the shallow nucleated Ag nanoparticles above the surface. The synthesized nanoparticles can be split into two groups: (i) located at the surface and (ii) fully embedded in the shallow layer. These two groups provide corresponding spectral bands related to localized surface plasmon resonance. The bands demonstrate considerable intensity making the synthesized composites promising for plasmonic applications. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 664–672     

High-yield Carbonization of Cellulose by Sulfuric Acid Impregnation

The carbonization of cellulose with sulfuric acid impregnation was studied by thermogravimetric analysis and scanning electron microscopy. The mass yield of carbon after 800°C treatment in nitrogen increased to 2–3 times by addition of small amounts of sulfuric acid. The sulfuric acid is considered to work as dehydration catalyst, thus suppressing the release of volatile organic substances. The shrinkage of the sample during carbonization was also significantly reduced by the addition of sulfuric acid.     

Preparation of biocarbon micro coils

ABSTRACT

A novel synthetic polymer-plant-precursor carbonization technique was developed. Carbon micro coils were prepared by the carbonization of plant helical vessels coated with polyaniline or poly(acrylonitrile-co-acrylic acid). The helical vessels served as a helical guide, while the synthetic polymers coated on the vessel surface, which consisted of cellulose, were transformed into carbon material while retaining the helical form. The helical carbon material was prepared without the use of an organic gas or solvents through a relatively simple and convenient process. This technique involved the application of natural resources, the synthesis of a conducting polymer, and carbon science. The biocarbon micro coils thus prepared in this study were characterized by infrared absorption, optical microscopy, and scanning electron microscopy. Moreover, the magnetic properties of the helical carbon were examined by electron spin resonance and a superconducting quantum interference device that proved its paramagnetic features. Additionally, the water transport function in the helical vessels was discussed.