Adsorption Capability Of Activated Carbon Research Articles

Effectiveness and mechanisms of the adsorption of carbendazim from wastewater onto commercial activated carbon.

The wide application of fungicides is becoming one of the main causes of water pollution. Activated carbon (AC) is a frequently-used adsorbent in water treatment. In this work, aiming to obtain a better understanding of fungicides on AC, carbendazim was selected as a model fungicide in water. The effects of AC dosage, adsorption temperature, adsorption time and pH value of solution on carbendazim adsorption by AC were investigated. When the initial concentration of carbendazim was 500mgL-1 and the volume of wastewater was 25mL, the optimum dosage of AC and reaction time was determined to be 0.3g and 150min, respectively. The pH ranging from 3.0 to 10.0 exhibited little effect on the adsorption capability of AC. The higher the adsorption temperature was, the better adsorption capacity was. Adsorption capacity could reach 32.31mgg-1 under the optimal adsorption conditions. The kinetics study reveals that the adsorption of carbendazim occurred on the surface of adsorbent during initial stage. The adsorption data was well fitted by Langmuir adsorption isotherm, indicating that the adsorption process was monolayer adsorption. The thermodynamic experiments confirmed that the adsorption of carbendazim was an endothermic process with the coexistence of physical and chemical adsorption. Because the main components of AC used in this research work is amorphous carbon with low impurity and its surface has not been modified with additional functional groups, the conclusion of the study was easy to be replicated by repeated experiments. Therefore, the findings of this study could guide the adsorption of carbendazim onto the other kinds of AC with high specific surface area, and provide useful information for application of commercial AC in treatment of fungicides wastewater.

Quantum chemical study on adsorption of hydrogen chloride on Zn-doped carbon materials

Abstract In previous studies of HCl adsorption on Zn-doped O 2 activated carbon (AC) at 100 and 300 °C, we revealed that Zn-doped carbon adsorbed far more HCl than undoped carbon. However, the effect of metals on the adsorption capability of AC and the mechanism of the adsorption stability of HCl have not yet been clarified. Herein, we used molecular orbital (RHF/6-31G ∗ ) calculations for three carbon active site models (Armchair, Zigzag, and Tip types) to investigate the effect of Zn doping on HCl adsorption via the estimation of the electronic states. The molecular models of the carbon materials with or without Zn doping showed that the presence of Zn increased the number of active sites available for the chemical adsorption of HCl molecules. Furthermore, Zn did not contribute to the adsorption stability of HCl in the Zigzag type model. Zn doping was found to change the electronic state of the active site of the carbon material in the direction in which HCl was readily adsorbed. This study lays the conceptual foundation for suppressing the formation of environmentally harmful volatile compounds from HCl generated in high-temperature processes via the modification of carbon materials to increase HCl adsorption.

Modification of Activated Carbon by the Basic Ionic Liquid [Bmim]OH: A Feasibility Study

AbstractThe large amount of dye wastewater requires efficient techniques, e.g., adsorption by activated carbon (AC), for removal of dyes to decrease water pollution. AC was modified by the basic ionic liquid 1‐butyl‐3‐methylimidazolium hydroxide. The surface functional groups of AC changed evidently as detected by Fourier transform infrared spectroscopy and Boehm titration. To evaluate the influence of functional group change on adsorption performance, AC and modified activated carbon (MAC) were employed to remove methylene blue. The results indicated an increase of adsorbance with lapse of contact time. The adsorption capability of AC was distinctly higher than that of MAC. From kinetic studies it follows that the pseudo‐second‐order kinetic model can well describe the adsorption process.