Papers by Keyword: Modified Activated Carbon

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Authors: Zhen Zhong Liu, Hui Ping Deng, Zhan Li Chen
Abstract: Modified activated carbon composites were prepared and their catalytic properties were evaluated in the H2O2 decomposition. Activated carbon alone showed very low activities compared to iron and manganese oxides / activated carbon composites, suggesting that the presence of Fe and Mn in the oxide plays an important role for the activation of H2O2. The presence of Mn in the composite structure produced a remarkable increase in the reactivity. The obtained results showed that the peroxide decomposition catalyzed by GACFM met pseudo-first-order kinetic and the maximum OH· production was on GACF1M3.The decomposition mechanism of H2O2 was analyzed in detail.
Authors: Lian Hai Ren
Abstract: The emission characteristics of volatile organic sulfur compounds (VOSCs) released from food waste processing plant were detected with cold enrichment-GC/MS. Four main sections of the plant including unloading room, crushing chamber, hydrothermal reactor and aerobic fermentation reactor were selected as sampling points. Results showed that the concentration of VOSCs of the four main sections were 0.085, 0.235, 1.175 and 0.245 mg/m3, respectively. Compared with other stages, the level of VOSCs of hydrothermal reactor was relatively high, and methyl mercaptan (MeSH) was the most abundant compound at this section. In order to remove the pollution of MeSH, modified activated carbon was used as the adsorbent. The influences of modified conditions, such as drying temperature, H3PO4 concentration and impregnated time on adsorption were investigated. Results showed that the amounts of acid groups and BET surface area of activated carbon had a significant impact on the adsorption capacity. When the drying temperature was 70°C, the H3PO4 concentration was 15% and the impregnated time was 3.0 h, the adsorption capacity of MeSH achieved the maximum value of 22.068 mg/g. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.
Authors: Xiao Lian Wang, Zhi Jie Ju, Xue Ping Huang, Fei Jin Xu
Abstract: The dynamic adsorption experiment of 2,4,6-trichlorophenol (TCP) to the modified activated carbon (MAC) was studied.The experimental results show that the dynamic adsorption effect of MAC for 2,4,6-TCP is favorable, and the penetrative point is 33h, the balance point is 99h. In addition, Yoon-Nelson model can accurately predict the penetration characteristics of 2,4,6-TCP solution on the modified activated carbon column, where ln[Ci/C0-Ci] and t keep a good linear relationship, and the correlation coefficient R2= 0.9727. Time t of 50% penetration concentration, penetration point t1 ,and balance point t2 calculated by Yoon-Nelson model fit with the experimental datas well.
Authors: Bing Nan Ren
Abstract: Carbon materials have a very large surface area and various surface functional groups. They have been widely used as the adsorbent alone or the modified surface to adsorb pollutants. In the process of producing of yellow phosphorus by electric furnace, about 3000 m3 tail gas will be let out for one ton yellow phosphorus production. Tail gases consist of 90% of carbon monoxide (CO) and phosphine (PH3). The PH3 prevents the highly efficient utilization of CO and is an irritant and general systemic poison. Therefore, it is necessary to study how to effectively remove PH3 in tail gases. Due to the fact that selective adsorption of non-modified activated carbon (AC) is not enough to remove PH3 with a high efficiency, modification of AC might be an attractive route to improve the adsorption capacity. In this paper, experiments were carried out to study the factors influencing the adsorption of PH3 on the modified AC such as the concentration of impregnant, reaction temperature, oxygen content and space velocity. The results showed that the 5% HCl was the optimum concentration of impregnant. In the presence of oxygen, the adsorption capacity of modified AC was more than that in the absence of oxygen. In addition, with the improvement of the reaction temperature, the adsorption capacity of modified AC was increasing initially then decreasing, because of the transition from physical adsorption to chemical adsorption as priority. The adsorption capacity of the modified AC was enhanced initially with the increasing of oxygen content. Once the oxygen content was enhanced over 1%, there was no significant increase in the adsorption capacity of modified AC. The adsorption capacity of modified AC was decreased with the increasing of space velocity. The optimum parameters of reaction were 5% HCl of impregnant, 70°C of reaction temperature, 1% of oxygen content, and space velocity 10~20min-1.
Authors: Rui Li
Abstract: The effects of nitrogen ligands as pyridine, methylpyridine, 2, 2'-bipyridine and ethylenediamine on the activity and stability of the CBAC supported copper catalyst were investigated. The catalytic activities prepared by nitrogen ligand pretreatment descended compared with the unpretreated support catalysts. This probably related to the disfavored effect of the coordination on the catalysts at the gas-solid reaction manner. The catalysts made by pyridine pretreatment and pore modified supports were superior to the catalysts of unmodified CBAC. Methanol conversion, DMC selectivity and the space-time-yield of DMC of the catalysts by HCl, pyridine pretreatment and pore modification were 28.3%, 97.3% and 165.3 g/(kg•h), respectively. Activity test of 30h showed that pyridine pretreatment can prevent the loss of the active component and enhance the stability of the catalysts.
Authors: Chun Sheng Ding, Fang Ming Ni, Hui Ye Cai, Qian Fen Zhu, Ying Long Zou
Abstract: To optimize the conditions of modification and understand the absorption mechanism of activated carbon, the orthogonal test was used to select the best conditions of ammonia-modified activated carbon. The changes of activated carbon’s specific surface area, pore volume and surface acidic oxygen-containing functional groups were determined before and after modification by ammonia, and the equilibrium adsorption model for phenol was also explored. The results show that under the conditions of ammonia concentration of 10%, soaking time of 2h, activation time of 2.5h and activation temperature of 500°C, the best removal rate could be obtained. The specific surface area and pore volume of modified activated carbon were increased, whereas the acidic oxygen-containing groups of its surface were significantly reduced by 57.88% after modification. It means the surface polarity of carbon was decreased, and which was conducive to the adsorption of phenol, since phenol was a weakly polar substance. Both Freundlich and Langmuir model could reflect the adsorption behavior of modified activated carbon for phenol, while the Freundlich model was more properly, but for the unmodified activated carbon, Freundlich model was more suited to describe the adsorption behavior of phenol than Langmuir model.
Authors: Ming Jiang, Ping Ning, Zhong Hua Wang, Yang Wei Bai, Wei Chen, Wei Zhang, Rui Bo Wang
Abstract: For utilization of CO contained in tail gases of coal chemical industry, adsorption purification of HCN in closed carbide furnace tail gas was investigated on an activated carbon was modified with KOH (AC1) and the other activated carbon was modified with NaOH and sulfonated cobalt phthalocyanine (AC2). The experiment results show that two kinds of modified activated carbons are proved to be effective adsorbents for HCN removal, but the HCN adsorption capacity for AC2 is 1.47 times that for AC1. For AC2 adsorbent, the purification efficiency increased with the increase of oxygen content and adsorption temperature. The results show that, 1.5% for optimum oxygen content and 90°C for optimum adsorption temperature. The specific surface and the pore structure properties of AC2 adsorbent before and after HCN adsorption were tested by N2 adsorption experiments. The N2 adsorption tests show that, the predominant adsorption of HCN occurs in the micropores in radius 7.4~16.6 Å. Deactivated AC2 adsorbent could be restored to the original activated state, even after several regenerations.
Authors: Yu Chen, Zhe Guo
Abstract: In this study granular activated carbon loaded with ferric oxide hydrate (Fe-AC) as arsenic adsorbent was prepared by impregnation method. The influence of the kinds of ferric salt solution, the concentration of ferric salt solution, impregnation time and curing temperature on its arsenic removal effect was investigated. The optimal preparation conditions of the adsorbent were determined. And its adsorption properties of arsenic in aqueous solution were studied by static adsorption experiments. Results showed that when the dipping solution is 1.0 mol/L of Fe (NO3)3, impregnation time is 16h and the curing temperature is 60°C, the arsenic adsorption effect of the prepared adsorbent is best. The pattern of adsorption of As (V) with Fe-AC prepared under optimal condition well fit the Langmuir adsorption model, the correlation coefficient R2 is greater than 0.98, and the maximum adsorption capacity is up to 71.43 mg/g.
Authors: Xiao Pin Wang, Yi Hui Li, Cou Hua Zhu
Abstract: This paper studied the changes in the surface morphology and microcrystalline structure of GAC modified using the original activated carbon, HNO3, FeCl2·4H20, KMnO4. The micro pore structure on the surface is damaged after being treated by HNO3, and the transition pores increase; after being treated by FeCl2·4H20 and KMnO4, the carbon surface is irregular, and there is a protuberance, which is due to the irregular loading of manganese ions on the activated carbon surface. Then the roughness of the activated carbon increases and the size of graphite crystallite of GAC is also greatly reduced, showing obvious trend of fine grains. Meanwhile, the studies of the effect of removing the trichlorophenol from water after modification indicate that the results basically match. On this basis, the modified model is put forward.
Authors: Zhang Xian Liu, Pei Pei Sun, Song Tao Chen, Li Juan Shi
Abstract: The coal-fired power plant is the main anthropogenic source of mercury pollution. The mercury in flue gas exists as elemental mercury(Hg0), oxidizing state mercury(Hg2+) and particulate mercury(Hgp). Mercury speciation distribution in flue gas was influenced and controled by the factors including conditions of ignition, desulphurization or denitration and Based on the investigation of coal-fired power plant technologies of removing Hg, this research uses the modified activated carbon (MAC) and studies its removal efficiency. Result indicates that the uptake of Hg by MAC was﹥90%.
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