Non-linear modeling of kinetic and equilibrium data for the adsorption of hexavalent chromium by carbon nanomaterials:Dimension and functionalization

The adsorption capacities for the removal of hexavalent chromium from aqueous solutions by six carbon nanomaterials have been evaluated. Single-walled and multi-walled carbon nanotubes as received and after oxidation treatment, graphene oxide and reduced graphene oxide are the materials with different dimension and functionalization compared in this research. Carbon nanotubes have been modified using hydrogen peroxide as oxidizing agent under microwave radiation. The oxidation treatment on carbon nanotubes has a positive effect increasing the adsorbent–adsorbate interaction. Rate-controlling mechanisms and equilibrium data are analyzed using non-linear models. Non-linear method is proposed as the most suitable method for determining the kinetic and equilibrium parameters. The values of adsorption energy(E) obtained from the Dubinin–Radushkevich isotherm,have been found around 0.371 and 0.870 k J·mol~(-1), indicating physical adsorption. Therefore, the pseudo-second order model represents better the kinetic experimental data. The results show that the Langmuir isotherm provides a slightly better fit to the experimental data compared with the Freundlich isotherm, indicating homogeneous distribution of active sites on carbon nanomaterials and monolayer adsorption. The separation factors RLare found in the range of 0–1, suggesting that the adsorption process is suitable for all adsorbents. The mechanisms for hexavalent chromium removal have been proposed as electrostatic interactions and hydrogen bonding.     

Thermal conductivity of natural rubber nanocomposites with hybrid fillers

Natural rubber nanocomposites filled with hybrid fillers of multi-walled carbon nanotubes(CNTs) and carbon black(CB) were prepared. CNTs were ultrasonically modified in mixture of hydrogen peroxide(H_2O_2) and distilled water(H_2O). The functional groups on the surface of CNTs, changes in nanotube structure and morphology were characterized by Fourier transform infrared spectroscopy(FT-IR), Raman Spectroscopy, and transmission electron microscopy(TEM). It shows that hydroxyl(OH·) is successfully introduced. The surface defects of modified CNTs were obviously higher than those of original CNTs, and the degree of agglomeration was greatly reduced. Thermal conductivity of the composites was tested by protection heat flow meter method. Compared with unmodified CNTs/CB filling system, the thermal conductivity of hybrid composites is improved by an average of 5.8% with 1.5 phr(phr is parts per hundred rubber) of hydroxyl CNTs and 40 phr of CB filled. A three-dimensional heat conduction network composed of hydroxyl CNTs and CB, as observed by TEM, contributes to the good properties. Thermal conductivity of the hybrid composites increases as temperature rises. The mechanical properties of hybrid composites are also good with hydroxyl CNTs filled nanocomposites; the tensile strength, 100% and 300% tensile stress are improved by 10.1%, 22.4% and 26.2% respectively.     

Process of Developing Carbon Black Industrial Power——Summary of 65-year Development of China Carbon Black Industry(1)

正Carbon black is invented by the Chinese.3000years ago,our ancestors grasped the technology of making ink by burning ashes.Even so,in old China,only Taiwan Jinshui once built the gas channel black factory and later Fushun and Anshan built the lamp black factory.When the new Chiua was founded in1949,China could only produce a small amount of lamp black,and the national output of carbon black     

Elemental C,H and N microanalysis of crushed rock and soil samples

A sensitive and reproducible method for elemental analysis of rock and soil samples has been developed using a modified Hewlett-Packard 185 CHN analyzer. Samples are combusted in an inert He atmosphere (with and without catalyst) with a carefully controlled combustion time and temperature. Absolute mass calibration is available on samples of from 1–500 μg total CHN content. Analysis of chromatograms is made by both manual and computer techniques. Finely crushed rock (or dust) samples of from 50–100 mg may be analyzed for most forms of carbon content and for N and H with a high degree of technical reproducibility. Step-wise calcination at 150 C and 550 C allows evaluation of adsorbed CO₂, potential organic and amorphous carbon content. Although carbide carbon is partially recovered, essentially quantitative recovery of finely divided graphitic (and diamond) as well as amorphous, carbonate and all organic carbon may be obtained. Presented in part at the AOCS Meeting, Houston, May 1971.     

Effect of Carbon Source on Crystal Morphology of SiC in-situ Formed in AI2O3-Si-C Matrix

Three kinds of Al2O3- Si- C matrix specimens were prepared using tabular corundum powder and Si powder as starting materials,ultrafine flake graphite,nano carbon black,and carbon nanotubes as carbon sources,respectively,to research the effect of micro or nano carbon materials on structure and morphology of formed Si C crystals. The specimens were fired at 1 000,1 200 and 1 400℃ for 3 h in carbon-embedded condition,respectively.The phase composition was studied by XRD and the crystal morphology of Si C was investigated by FESEM. The results show that:( 1) the amount of Si C increases with the firing temperature rising;( 2) the in-situ reaction mechanism and the formed Si C crystal morphology vary with carbon source: carbon nanotubes are generally converted into Si C whiskers by carbon nanotubes-confined reaction; Si and nano carbon black react to nucleate quickly,and the nucleated Si C crystals grow evenly in all directions forming Si C particles; Si C whiskers are produced from edge to internal of ultrafine flake graphite.     

Effect of Nano Carbon Black and Graphite Flake on Properties of Low Carbon Al_2O_3-C Refractories

Low carbon Al_2O_3-C refractories specimens were prepared with tabular alumina( 3. 0- 1. 0,1. 0- 0. 5,0. 6- 0. 2,≤0. 3,≤0. 045 and ≤0. 02 mm),active alumina micropowder( ≤2 μm) and silicon( ≤0. 045mm) as main raw materials. Nano carbon black( N220) and natural graphite flake( ≤0. 074 mm)were adopted as the carbon sources. The specimens were treated at 800,1 000,1 200 and 1 400 ℃ under coke embedded atmosphere. The effects of additions of nano carbon black and graphite flake on mechanical properties and thermal shock resistance of the specimens were studied. Their mechanical properties were measured by threepoint bending test and thermal shock resistance was determined by water quenching method. The phase composition of the specimens was analyzed with X-ray diffraction and microstructures were observed through FESEM.The results reveal that:(1) the strengths of Al_2O_3-C refractories with these two carbon sources show no big differences when coked at lower than 1 000 ℃; when coked at over 1 200 ℃,the strengths of the specimens with graphite added are much higher than those of the specimens containing carbon black due to much more silicon carbide whiskers formed;( 2) since the nano carbon black has small particle size,they can be filled into interstice of Al_2O_3 particles to form the nano carbon network structure,absorbing and relieving the thermal stressgenerated from expansion and contraction and reducing the thermal expansion coefficient of the specimens,thus their thermal shock resistance is better than that of the specimens containing graphite;( 3) low carbon Al_2O_3-C refractories with good mechanical properties and excellent thermal shock resistance can be prepared with combination of nano carbon black and graphite flake.     

Platanus orientalis leaves based hierarchical porous carbon microspheres as high efficiency adsorbents for organic dyes removal

Water contamination caused by hazardous organic dyes has drawn considerable attention, among all of the techniques released, adsorption has been widely used, which however to a large degree is dependent on the development of high efficiency adsorbents. Waste biomass based porous carbon is becoming the new star class of adsorbents, and thus contribute more to the sustainable development of the society. In this work, for the first time to the best of our knowledge, abundant waste fallen Platanus orientalis leaves are employed as the raw material for hierarchical activated porous carbon(APC) microspheres via a mild hydrothermal carbonization(210 °C,12.0 h) followed by one-step calcination(750 °C, 1.0 h). The APC microspheres exhibit a specific surface area of1355.53 m~2·g~(-1) and abundant functional groups such as O—H and C=O. Furthermore, the APC microspheres are used as the adsorbents for removal of Rh B and MO, with the maximum adsorption capabilities of 557.06 mg·g~(-1) and 327.49 mg·g~(-1), respectively, higher than those of the most porous carbon originated from biomass. The adsorption rates rapidly approach to 98.2%(Rh B) and 95.4%(MO) within 10 min. The adsorption data can be well fitted by Langmuir isotherm model and the pseudo-second-order kinetic model, meanwhile the intra-particle diffusion and Boyd models simultaneously indicate that the diffusion within the pores is the main rate-limiting step. Besides, the APC microspheres also demonstrate good recyclability, and may also be applied to other areas such as heterogeneous catalysis and energy storage.     

Lithographic and letterpress ink vehicles from vegetable oils

Our objectives for this study were to produce vegetable oil-based printing ink vehicles that did not require any petroleum components, which meet or exceed industry standards for rub-off resistance, viscosity and tackiness for a variety of printing applications. These objectives were satisfactorily met. Vehicles were completely compatible with carbon black, making them suitable for black ink formulations. In addition, the resulting vehicles had exceptionally light colors, and permitted formulations of colored inks that had substantially reduced pigment levels compared to industry standards.     

Development of karanja oil based offset printing ink in comparison with linseed oil

The conventional offset lithographic printing ink is mainly based on linseed oil. But in recent years, due to stiff competition from synthetic substitutes mainly from petroleum products, the crop production shrinks down to an unsustainable level, which increases the price of linseed oil. Though soyabean oil has replaced a major portion of linseed oil, it is also necessary to develop alternate cost effective vegetable oils for printing ink industry. The present study aims to evaluate the performance of karanja oil (Pongamia glabra) as an alternative of linseed oil in the formulation of offset printing ink because karanja oil is easily available in rural India. Physical properties of raw karanja oil are measured and compared with that of alkali refined linseed oil. Rosin modified phenolic resin based varnishes were made with linseed oil as well as with karanja oil and their properties are compared. Sheetfed offset inks of process colour yellow and cyan is chosen to evaluate the effect of karanja oil in ink properties. In conclusion, karanja oil can be accepted as an alternate vegetable oil source with its noticeable effect on print and post print properties with slower drying time on paper. However, the colour and odour of the oil will restrict its usage on offset inks.     

Development of mineral oil free offset printing ink using vegetable oil esters

Until the middle of this century, fats and oils are the major raw material source for paints, coating and lubricating applications. These markets are completely taken over by petroleum based stocks due to their abundance and versatility. However, recent public awareness to use environmentally acceptable products that minimize pollution, are compatible to human health and readily biodegradable created opportunities for vegetable oils for application in paints and printing inks. The formulation of vegetable oil methyl ester based 'green' offset printing ink that reduces the volatile organic compounds (VOC) has been discussed in the present study. Methyl esters of rapeseed, soybean, rice bran and palm oil have been prepared and their physical properties have been measured and compared with standard petroleum feed stock. Varnishes were prepared with these esters and their properties are also compared with that of the petroleum based products. Rheological properties of the inks are also evaluated and compared with standard printing ink using petroleum based solvent. In general performance of the ester-based printing inks are comparable with that of the mineral oil based product. On the basis of tack stability and gloss, ester based inks are much superior than the mineral oil based products. In conclusion, a new non-volatile diluent for printing ink has been developed. The diluent is made from common vegetable oils like rapeseed, soybean, rice bran and palm oil, a renewable source that is environmental friendly. Vegetable oil esters offer a cost effective solution for mineral oil based printing ink to meet VOCs regulations.     

不同类型偶联剂对热解炭黑的表面改性及应用研究

采用偶联剂Si69、钛酸酯类偶联剂、活化剂450和活化剂480对半钢子午线轮胎热解炭黑进行了干法表面改性,探究了改性热解炭黑在天然橡胶中的应用性能。结果表明,活化剂450对热解炭黑具有一定的改性效果,其硫化胶拉伸强度提高了5%左右,耐磨性提高了20%左右;其他活化剂对热解炭黑的改性效果不大,酞酸酯类偶联剂改性热解炭黑会降低硫化胶力学性能。     

废旧轮胎裂解炭黑的改性及其应用进展

废旧轮胎作为对环境有害的固体废弃物，其组成包括炭黑、白炭黑和胶粉等多种有价值的资源。在现有回收技术中，废轮胎热裂解技术可有效回收裂解油、炭黑和钢丝等，在国内获得了广泛应用。相对于已经普遍利用的热解油和钢丝来说，热解炭黑含有质量分数14-21%的灰分和胶质层，它的高价值利用是实现废旧轮胎循环回用的关键。很多研究者开展了热解炭黑不同的改性处理工艺研究，改性后的热解炭黑可被应用于多个领域。该文主要概括了热解改性炭黑在橡胶生产中的补强作用、改性活性炭吸附剂、电池材料、以及沥青和油墨填料等方面的应用，综述了上述应用领域内热解炭黑的处理和改性方法，并指出今后热解炭黑高价值回用的方向和改性方法。     

水溶性醇对中性墨水性能的影响

分别考察了与分散树脂SMA(苯乙烯-马来酸酐树脂)相容的6种水溶性醇对炭黑颜料色浆的分散稳定性,中性墨水的触变性、保湿性与书写性能的影响。结果表明,聚乙二醇200、聚乙二醇400和甘油均与SMA具有较好的相容性;以聚乙二醇400制得的炭黑色浆分散稳定性最佳;与SMA相容性好的水溶性醇随其添加量的变化会对中性墨水触变值产生较大的影响;甘油、乙二醇与聚乙二醇400都可使中性墨水具有良好的保湿性;甘油、聚乙二醇200与聚乙二醇400所制备的中性墨水出墨量稳定、线条均匀,书写性能良好。     

Use of effect pigments for quality enhancement of offset printed specialty papers

Nowadays, effect pigments are widely used in many printing industries. The colorful effects produced by light scattering of these types of pigments add an additional value to the prints and enhances the overall quality of color appearance. The aim of this study was to investigate the quality enhancement of printed specialty papers with various effect pigments in combination with offset inks. Four different effect pigments were used (one luster pigment‐EP1, two interference pigments‐EP2, EP3, and one multicolor pigment‐EP4) as well as two types of paper substrates (film synthetic paper and wood‐free paper). The effect pigments were overprinted on dried CMYK offset prints on both paper substrates. The following analysis were performed: scanning electron microscopy analysis of effect pigment particles, contact angles of papers and offset prints, Fourier transform infrared spectrocopy (FTIR), principal components analysis (principal components analysis (PCA)), and flop index analysis of overprinted effect pigments, and paper and print gloss. The results of the experiment indicate that effect pigments behaved differently on different printing substrates. From the FTIR and PCA, it was found that the different composition of effect pigments differently influence the behavior of these particles on the final prints. Effect pigments overprinted on offset CMYK inks on both paper substrates enhance print gloss, except interference pigment EP2 on film synthetic paper. It was also found that the ink color has the most pronounced influence on flop index, followed by the papertype and the type of effect pigment. Higher flop index was obtained at wood‐free paper, especially by overprinted pigment EP2. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 168–176, 2013.     

一种热转印色带中黑颜料的分离及分析

热转印黑色带油墨层是黑颜料与树脂的分散体系 ,采用氧化铝柱层析法分离颜料与树脂 ,得到吸附有颜料的氧化铝 ,经过红外、元素分析、电感耦合等离子体发射光谱和热分析质谱和热分析质谱分析鉴定了黑颜料的成分为碳黑。     

The Use of Fluorocarbon Surfactants to Improve the Manufacture of PEM Fuel Cell Electrodes

Fluorocarbon surfactants are used to improve surface wetting during the screen printing of carbon black inks onto PEM fuel cell electrodes. The fluorosurfactants were tested in inks that comprised a Nafion® ionomer solution with platinum‐loaded carbon black. Four commercially available fluorosurfactants (Zonyl FSO, Zonyl 1033D, Forafac 1098 and Novec FC 4430) were screened and assessed for electrochemical activity (via cyclic voltammetry), leaching and the ability to form ink layers. Good wetting characteristics were observed and the inks showed a similar specific electrochemical active area (200–430 cm² mg^–1 Pt) to a standard reference ink (370 cm² mg^–1 Pt), indicating that the surfactants did not adversely adsorb on the platinum catalyst surface or block the adsorption/desorption of hydrogen. Additionally, the fluorosurfactants in the cured inks were shown to be electrochemically inactive in the potential region relevant to fuel cell operation.     

Influence of nano‐coated pigment ink formulation on ink‐jet printability and printing accuracy

Pigment ink was formulated with nano‐coated pigment dispersion, prepared via mini‐emulsion polymerization. To study the effect of nano‐coated pigment, surfactant and humectant on ink‐jet printability, the trajectory of droplets with different pigment ink composition was monitored. The effect of ink formulation on the accuracy of printing process of the pigment ink was discussed by study on line width and edge contour of printed patterns. Experimental results indicated that the additives and properties of the pigment ink had a great influence on droplet formation and precise positioning of the printed patterns. The optimal composition for the pigment ink as following: nano‐coated pigment dispersion was 20% w/w, surfactant (S‐465) was 1.5% w/w, humectant (diethylene glycol) was 30% w/w and defoamer (FB‐50) was 0.1% w/w. The prepared pigment ink exhibited excellent freeze–thaw, thermal and centrifugal stability. In addition, the optimal formula was beneficial to form a stable droplet and obtain high precision patterns.