| The use of coal-based bio-activated carbon in water treatment provides an efficient and long-term method for better handling micro-polluted water sources.It combines the adsorption of activated carbon with the biodegradation of microorganisms to achieve better water treatment and longer period of use.However,long-term use leads to the adsorption of a large number of water pollutants,which covers the surface of activated carbon,which not only affects the activity of the biofilm seriously,but also makes pore saturated.Finally,it will become the saturated coal-based bio-activated carbon.There are a lot of methods to regenerate activated carbon,but the methods for the regeneration of saturated coal-based bio-activated carbon in water treatment cannot be seen often and the existing regenerative equipment is large and consuming.Therefore,in this dissertation,thermal-electrical regeneration is combined,which focuses on improving the existing equipment and the test equipment is rebuilded.Based on the new low voltage arc discharge regeneration,the regeneration of coal-based bio-activated carbon in water treatment is studied.finally,the regeneration is successful and the adsorption capacity of iodine and methylene blue are recovered to more than 90%.And the experiment was compared with the thermal regeneration of tubular furnace and the regeneration of the old equipment.The details are as follows:(1)The background of this project and the methods of regeneration of saturated bio-activated carbon in water treatment are reviewed.Their respective advantages and disadvantages as well as new research directions,methods and theories are emphasized.(2)The apparent resistance of saturated coal-based bio-activated carbon under the experimental conditions is explored.The influencing factors of pretreatment temperature,moisture,flow rate and biofilm are analyzed.The effects of electrode plate spacing are discussed and more favorable experiment conditions are concluded.The old equipment is improved and innovated,which adopt more reasonable spacing,compact structure,quartz glass and make it miniaturized.The low voltage arc discharge regenerative experimental device is builded.According to the structure of the experimental device and the weighing of the sample.The quantity of sample needed for each experiment is determined which is 6.0kg.(3)Simulating traditional thermal regeneration with tubular furnace,the result is described briefly;the regeneration experiment and results of the old thermal-electric are summarized;the regenerative experiment of low voltage arc discharge is emphasized and the voltammetric characteristics of the regeneration process are analyzed.The feasibility of three-segment low-voltage is verified.The principle of arc discharge and the discharge phenomenon are analyzed,and the results show that the principle of arc discharge is authentic in regeneration.The quality loss of the samples in the experiment is about 20%,and the results of the adsorption performance reflected the best experimental conditions.(4)Based on Thermogravimetric and infrared spectra,three regenerated samples(RAC)and NAC and SBAC are compared and analyzed.The desorption process of samples is divided into four different stages and the pyrolysis and desorption process of each sample is analyzed in detail.The effect of carbon on the sample is eliminated by using pure carbon powder.The results show that the effect of carbon is very small and can be neglected.The products are analyzed by spectral graphs,and the respective products were analysed,and the effects of three kinds of different regenerated samples are studied,and the optimal regenerated samples of three different regeneration methods are compared laterally.(5)Some physical and chemical properties as well as the characteristics of adsorption properties are characterized and analyzed.Including particle size distribution,particle crushing strength,morphology,surface elemental analysis and determination of iodine value and methylene blue value. |
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