Papers by Keyword: Activated Carbon (AC)

Abstract: In this work, a novel method was reported for preparation of Ru/activated carbon (Ru/AC) catalysts. Supercritical carbon dioxide (SC CO₂) was employed as medium for the impregnation of ACs with inorganometallic precursor of RuCl3. The Ru/AC catalysts displayed excellent activity for the catalytic hydrogenation of D-glucose. Selected Ru/AC catalysts were characterized by N₂ adsorption-desorption, TPR and TEM analysis. The results show that the order of effects on catalytic activity are supercritical temperature > supercritical pressure > amount of co-solvent > time of impregnation. The optimal supercritical parameters for preparing Ru/AC catalyst were 313 K, 8 MPa, 4 ml of methanol and 9 h, respectively. The highest reaction rate of hydrogenation reached 86.35 mmol•min-1g-1Ru, upgrading 42.96% compared with the activity of conventional Ru/AC prepared using aqueous impregnation. The SC CO2 impregnation could result in Ru uniformly dispersed on the outer surface and in the pore of AC, leading _{Subscript text}to higher dispersion of Ru and enhanced interaction between AC and Ru. Furthermore, the enhanced interaction induces improved reduce temperature. Consequently, the catalytic activity of Ru/AC catalysts is improved significantly.

Abstract: In this work, activated carbon was modified by ammonia water. Cyclic voltammetry and constant current charge-discharge were used to characterize the electrochemical performance of the samples in 1.0 mol/L Et₄NBF₄-PC solution. As a result, optimal conditions for surface modification of activated carbon have been examined as an ammonia solution concentration of 5wt.%. Specific capacitance can be improved significantly by surface modification of carbon materials. The specific capacitance of the carbon modified with 5.0wt.% ammonia water reached 114 F/g at a current density of 3.0 mA/cm2, which is 14% higher than that of untreated sample. In addition, the modified carbon materials possess excellent power performance.

Abstract: _{Subscript text}An adsorbent has been prepared from Heishan coal by chemical activation with KOH, the activated carbon has a BET surface area of 801.53 m2/g, the meso-pore ratio is 89.63%, SEM image shows that it is very rich in pore structure. The activated carbon was used to adsorb malachite green from an aqueous solution in room temperature. The effects of pH, contact time and dosage have been studied. The results show that the adsorption of malachite green from aqueous solution onto Heishan coal-based activated carbon proceeds according to the pseudo-second-order model, the adsorption equilibrium data were better represented by the Langmuir isotherm than Freundlich isotherm.

Abstract: The aim of this paper is to study the adsorption characteristics of nitric oxide (NO) and sulfur dioxide (SO₂) on raw coal activated carbon over temperature ranged 298～343K using a static volumetric adsorption apparatus. The adsorption equilibrium data for NO and SO₂ were fitted to Freundlich, Dubinin-Radushkevich (D-R) and Sips adsorption isotherm model. Isosteric heat of adsorption was determined by the Clausius-Clapeyron equation. It was found that Sips adsorption isotherm model is more suitable for description of NO adsorption process at 298K, 313K and 328K and SO₂ adsorption process at 313K, 328K and 343K, however, D-R adsorption isotherm model is more suitable for description of the NO adsorption process at 343K and SO₂ adsorption process at 298K. The isosteric heat of adsorption values of SO₂ increase slightly as the adsorbed amounts increasing from 0.8 to 1.6mg/g, but the isosteric heat of adsorption values of NO show a converse trend. Meanwhile, NO and SO₂ adsorbed on coal activated carbon at the four temperatures may be a dominant of physical adsorption.

Abstract: The effect of iron doping on physical and chemical properties of activated carbon, the effect of initial concentration and temperature on adsorption behavior of adsorbents for aniline from water, and adsorption equilibrium and thermodynamics were investigated. The results show that Fe doping obviously increase acidic oxygen-containg groups of activated carbon surface. Effect of Fe doping on adsorption capacity of aniline at the low concentration is insignificant. Equilibrium adsorption uptake decreases with an increase in adsorption temperaure. Freundlich model can better describe adsorption behavior of aniline on AC and Fe/AC. Aniline adsorption is spontaneous and exothermic.

Abstract: The activated carbon loaded copper oxide catalyst was prepared from Hainan abandoned coconut shells using chemical activation method and applied in treatment of acid bright red GR simulation dyeing wastewater. The effects of phosphoric acid concentration, ratio of liquid to solid, activation time and activation temperature on the COD and color removal rates were investigated by orthogonal experiment. The results showed that the optimal values of the parameters above were 65% (in mass), 3:1, 2.5h and 500°C under the designed copper oxide loading conditions of calcining temperature 300°C,calcining time 3.0 h and use level of copper nitrate 15 mL. Using the prepared sample for the treatment of the wastewater, the COD and color removal rates reached 94.384% and 99.840%, respectively.

Abstract: Response surface methodology was used to optimize the activated carbon iodine absorption value screened by Placket-Burman design. Six effective factors such as NaOH concentrations, boiling time, liquid ratio, calcined ways, calcined time and calcined temperature were tested by using Placket-Burman design criterion and three effective factors NaOH concentrations, liquid ratio and calcined time showed significant effect(P<0.05) on iodine absorption value. By applying Box-Behnken design, the optimized condition obtained NaOH concentrations of 2.5mol/l, liquid ratio of 1/1.125 and calcined time of 37.5min. Three runs of additional confirmation experiments were conducted. The average relative error was 0.58%.

Abstract: The conditions for the preparation of rubber (hevea brasiliensis) seed coat based activated carbon (RSCAC) treated with NaOH were optimized through response surface methodology (RSM). The effects of three preparation variables: the activation temperature, activation time and NaOH impregnation ratio (IR) on Remazol Brilliant Blue R (RBBR) removal from aqueous solutions and RSCAC yield were investigated. Based on the RSM, two quadratic models were respectively developed to correlate the preparation variables to the RBBR percentage removal and carbon yield. The significant factors on each experimental design response were identified from the analysis of variance (ANOVA). The optimum conditions for RSCAC preparation were obtained by using activation temperature of 700 °C, activation time of 1.0 h and IR of 1.0, which resulted in 70.82% of RBBR removal and 24.93% of RSCAC yield.

Abstract: By changing the hydrogen peroxide and ozone dosage,the best dosage of hydrogen peroxide to catalyzed ozone- activated carbon-sand filtration process in purify Yellow River Water was found. When the same amount of hydrogen peroxide is filled into the three-level Ozone oxidation column, the combined process’s effect is best.The removal rates of TOC,UV₂₅₄,COD_Mn,Turbidity are 27.72%,58.66%,43.30% and 84.90%,the organic content is reduced in a large extent and the finished water quality is improved.

Abstract: Removal of fluoride from drinking water using magnesia-amended activated carbon (MgO-AC) was investigated. The MgO-AC was characterized scanning electron microscope (SEM). Attempts were made to fit the isothermal data using Langmuir and Freundlich equations. The experimental results have demonstrated that the equilibrium data are fitted well by a Langmuir isotherm model and the maximum sorption capacity of fluoride evaluated is 7.22 mg/g. Thermodynamic parameters of ∆G0, ∆H0 and ∆S0 show that the adsorption is a spontaneous and endothermic process.