Papers by Keyword: Modified Activated Carbon

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.

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.

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 KMnO_4, 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.

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[C_i/C₀-C_i] 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.

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.

Abstract: After activated carbon is oxidized and modified with nitric acid (1:1), its cation exchange capacity can amount to 1.840 mmol • g^-1. The modified activated carbon is used as adsorbent for the treatment of Cr (Ⅵ)-containing wastewater at room temperature, and its removal mechanism is discussed in this paper. It is shown that: when the pH value of the aqueous solution being 2.5-3.0;the adsorption time being 3.0h, the removal rate of Cr (Ⅵ) in the aqueous solution can reach 97% and its adsorption capacity can amount to 45.66 mg • g^-1. From the results, it can be also seen that the adsorption curve to chromium in wastewater by the modified activated carbon better meets the Freundlich isotherm, and ion exchange adsorption mainly does its work.

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.

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(Hg_p). 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%.

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.

Abstract: To improve the adsorption efficiency of activated carbon for phenol, copper nitrate was used to modify activated carbon. In detail, the absorption properties of modified activated carbon was studied by investigating the effects of adsorption time, pH, amount of modified activated carbon and initial concentration of phenol on the adsorption. And the dynamic and adsorbent model were obtained and explored. It shows that the removal rate of modified activated carbon for phenol was higher than the unmodified carbon, and the best removal rate can be obtained under the conditions of pH about 5, adsorption time of 2h, modified activated carbon dosage of 1.0g. The quasi-two rate equation was better to reflect the dynamics of modified activated carbon for phenol, with the initial concentration of phenol increased, equilibrium adsorption capacity and initial adsorption rate were greater. Both Freundlich and Langmuir model could reflect the adsorption behavior of modified activated carbon for phenol, while the Langmuir model was more properly.