Study On Modification Of Activated Carbon Fiber And Adsorptive Properties For Organic Compounds In Wastewater From Coke Plant

In this paper, the viscose-based activated carbon fiber is used as materials to produce the modificated activated carbon fiber by microwave radiation,refluxing with nitric acid , microwave radiation-refluxing with nitric acid, and alkaline treatment, and the modification mechanism is explored.The pore distribution is analyzed through the adsorption isotherms for nitrogen and the surface function all groups and morphology are characterized with the help of IR spectra and SEM photos. The results from TG and DSC indicate that the thermal stability of modified activated carbon fiber is promoted.The static adsorption properties of the modificated activate carbon for the organic compounds difficult to degradate as indole,pyridine,and quinoline are observed. The breakthrough curves are determined for fixed bed with the modificated activate carbon fibre and A mathematical model is set up.The surface functional groups are detected. On the basis of researches for the desorption and degradation of organic compounds by microwave and supersonic wave,the wastewater from coal plants is treated using modificated activate carbon as absorbents.It is founded that the specific surface area and the microvolume is increased,and the affinity of adsorbent surface for nitrogen is enforced except the modificated activate carbon with alkali. Among the modification methods described above, microwave radiation is proved to be a simple one to increase the surface area in which the surface area and pore distribution can be justed by gas concentration and the flow rate.When the fractal theory is used for the description the heterogenousity roughness,it is founded that the surface fractal dimensions of modificated activate carbon are double.It was found the thermal stability of modified activated carbon fiber increased from TG and DSC curves.It can be used under 500℃ The surface functional groups and the microscopic structures are changed compared with the unmodified one from the IR spectra and SEM photos.The adsorption capacity for organic compounds in solutions are greater than that of unmodified one.The adsorption efficiency of activated carbon fiber was affected intensively by pH mainly due to its affects on the carried electric conditions of the fibre surfaces and organic compounds. It is found the interaction forces of the fiber with organiccompounds are dispersive force,hydrogen bonds and dipoles.A fixed bed was designed and manufactured, the effects of its main parameters as concentrations,the bed length,flow rate,etc on its various properties are discussed.The desorption can be expressed using first-order rate equations. At the same time, organic substances could be degraded by ultrasonic wave. The effects of irradiation time, concentration of organic substances, pH, temperature, power of the ultrasonic wave , and the catalysts on the degradation efficiency of organic substances are studied.The degradation of indole and pydine fits the first-order model of kinetics.A nonlinear kinetic model under the following hypothesis as (1) isothermal adsorption process,(2)homogeneous fixed bed, and(3)piston fluid.The numerical analysis for the model is carried on with Microsoft Visual FoxPro.6.0. It is shown that all these analysis result have a good agreement with experimental breakthrough curves.It is provided that the foundation for design of adsorption column about adsorption for wasterwater from coke plans.