| Activated carbon can easily lose its activity after adsorption of organic pollutants.If it is not regenerated,activated carbon will form secondary solid（critical）spent.At the same time,it will increase the cost of pollution control and cause the spent of non-renewable resources.Regeneration of spent activated carbon with low temperature plasma has the advantages of short regeneration time,high efficiency,and low loss of activated carbon.In this study,a self-developed corona dielectric barrier low temperature plasma reactor was used to study the regeneration of waste activated carbon.It provides theoretical support and application value for the utilization of waste activated carbon and the promotion of plasma in the treatment of environmental pollution.In this paper,a uniform design method was used to screen the appropriate parameters such as discharge time,discharge voltage,discharge frequency,and aeration flow rate,in order to obtain optimized discharge parameters of the homemade reactor.To test the regenerative performance of the waste activated carbon treated by the corona dielectric barrier co-discharge treatment of the reactor,the activated carbon regeneration efficiency was used as an index to compare the regeneration effect of the commercially available pellets and columnar activated carbon,and the waste activated carbon adsorbing benzene series aniline and azo fuel methylene blue.SEM and FIIR were used to analyze the change of phase properties of activated carbon.In order to obtain the law of pollutant degradation in high-voltage electric fields and its interaction with active particles,the fractal-like and Langmuir kinetics analysis was used to reveal the dynamic characteristics of material change and transformation in high voltage fields.Using the pollutant purification efficiency as a probe,the effects of adsorbing phenolic paint waste activated carbon and regenerating waste activated carbon from automotive painting workshops were examined.The environmental-economic-social benefit evaluation of spent activated carbon regeneration was conducted.Research indicates:（1）The reactor discharge parameters obtained by the uniform design method are:reactor voltage is 12 kV,frequency is 9.5 kHz,and air flow is 0.5 L/min.After using air as the background gas,the column-type waste activated carbon adsorption efficiency of0.4000 g for adsorbing aniline was 59.32%after 25 minutes of discharge.The resulting reproductionequationwasY=19.561-0.006X1X2X3X4-0.056X2X2+0.992X3X3+0.275X1X2,R=0.995,F=46.707>F（4,2）=19.3.High model significance indicates that the model is available.There is interaction between discharge time and discharge voltage.When the reactor is discharged under suitable parameters,the O3 concentration can reach 4680.09 mg/m3,the energy efficiency is 6985.2 J/L,and the discharge power is58.21 W,which is 0.33 times that of the existing dielectric barrier discharge power.（2）Under the suitable discharge parameters,the regeneration efficiency of waste activated carbon adsorbed by aniline can reach 82.02%,and the activated activated carbon can reach 87.52%,after the waste activated carbon was regenerated with corona dielectric barrier co-discharge for 30 min.After the waste activated carbon with aniline adsorbed was regenerated for 25 min,the column waste activated carbon regeneration efficiency was 81.03%,and the granular waste activated carbon regeneration efficiency was 59.13%.After regeneration for 5 times,the regeneration efficiency of columnar waste activated carbon adsorbing aniline was 67.68%.The reactor showed good regeneration performance,and the activated carbon exhibited good adsorption performance after regeneration.（3）The gas-solid reaction theory was used to explore the diffusion law of O3.It was found that the O3 diffusion conforms to the Langmuir classical kinetic model.The equation is y=0.0009x+0.006（R2=0.9692）.The chemical reaction of aniline and O3 on the surface of spent activated carbon accords with fractal dynamics.The kinetic equation of columnar activated carbon reaction is y=-0.9700x-0.5323（R2=0.9636）,reaction dimension D1=2.03,kinetic equation of granular activated carbon reaction is y=-0.6851x-2.6041（R2=0.9953）,D2=2.31;D1<D2,the dimensional analysis shows that the surface roughness of granular activated carbon is greater than that of columnar activated carbon.（4）In the regeneration process of waste activated carbon,the regeneration effect of spent activated carbon in the early stage of discharge is affected by the structure of the contaminants.The more complex the molecular structure,the relatively low regeneration rate.The multi-layer physical adsorption of activated carbon helps to trap active particles,which in turn facilitates the adsorption of pollutants from waste activated carbon and oxidation reactions.Analyzes the degradation product of waste active aniline.It is found that the C-N on aniline in the high-voltage electric field is easy to crack first.The oxidized intermediates are aldehydes,acids,alcohols and alkanes.No toxic by-products are detected in the final product.（5）The waste activated carbon adsorbed with phenolic paints was regenerated by corona dielectric barrier synergistic discharge.It was found that when the reactor was discharged under suitable discharge parameters for 20 min,the VOC purification efficiency was 99.77%.The monitoring values of O3 and VOC in the exhaust gas are reduced to 0 mg/m3,and the VOC and O3 emissions are achieved during the regeneration process.After 25 minutes of regeneration treatment of industrial waste activated carbon from a car painting shop,the pollutant purification efficiency can reach95.22%.The monitoring value of O3 and VOC in the exhaust gas can also be reduced to0 mg/m3,and the VOC and O3 emissions can be achieved during the regeneration process.It shows that when the self-made reactor is used to adsorb activated carbon with high concentration and complex organic pollutants,it has better removal effect of adsorbed pollutants and realizes regeneration treatment of waste activated carbon. |
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