【作者】 李娜；

【导师】 李杰；

【作者基本信息】 大连理工大学 ， 环境工程（专业学位）， 2022， 硕士

【摘要】 活性炭吸附法能有效处理难降解有机废水,但其只是将污染物从液相转移至固相,并没有达到彻底去除污染物的目的,若将未处理的活性炭直接丢弃,会导致二次污染和资源浪费,因此再生活性炭具有重要意义。本文针对介质阻挡放电等离子体再生活性炭存在活性物质传质效率低、水中放电等离子体高压电极易腐蚀及H₂O₂等活性物质氧化能力不足的问题,提出多针-板鼓泡脉冲放电（Multi-pin Plate Bubble Pulse Discharge,MPPBPD）等离子体耦合Fenton反应再生吸附苯酚活性炭的方法,以实现低温等离子体稳定、高效地再生活性炭。具体研究内容及结果如下:（1）构建MPPBPD再生体系,考察了不同实验参数对MPPBPD等离子体理化特性的影响规律。表明低压电极的结构对理化特性无显著影响。单次脉冲注入反应器的能量随电极间距的减小、溶液电导率和载气量的增加而增加,随炭水比的增加呈现先增加后降低趋势。电压和电导率的增加、p H的减小有利于活性粒子H₂O₂、O₃的生成。（2）研究了活性炭位于MPPBPD体系中高低压电极之间的再生性能,分析了该放置方式对活性炭表面形貌的影响。表明,随电压的增加、电极间距的减小、再生时间的延长以及炭水比的减小,再生率增加能量效率降低。随载气量的增加、活性炭与高压电极之间距离的减小,再生率和能量效率均增加。在电压12 k V、电极间距20 mm、电导率750μS/cm、p H=6、载气量6 L/min、炭水比1:10、活性炭距离高压电极0 mm、再生30 min的条件下,再生效果最好,再生率和能量效率分别为126%和15.2 kg/k Wh,苯酚降解率为86%,粉末率为4%,质量损失率为4%,且再生得到的粉末炭凹凸不平。（3）研究了活性炭位于MPPBPD体系中低压电极之上的再生性能,分析了该放置方式对活性炭表面形貌的影响。研究结果表明,在电压14 k V、电极间距10 mm、再生液电导率750μS/cm、p H=6、载气量6 L/min、炭水比1:10、再生30 min的条件下,活性炭的再生效果最好,再生率和能量效率分别为88%和7.5 kg/k Wh,苯酚降解率为88%,粉末率为0%,再生炭质量几乎不损失,且表面平整、结构完整。（4）利用活性炭位于MPPBPD的低压电极之上再生系统,构建了MPPBPD+Fenton耦合再生体系,探究了该体系的再生性能,对比了MPPBPD再生体系与耦合再生体系的活性炭再生效果、苯酚污染物降解效果。研究结果表明,再生率随Fe²⁺浓度以及p H的增加呈现先增加后降低的趋势。随着载气量的增加、再生时间的延长、炭水比的减小,再生率呈增加的趋势。在电压14 k V、电极间距10 mm、Fe²⁺浓度260 mg/L、电导率1500μS/cm、p H=3、载气量6 L/min、再生时间30 min、炭水比1:10的条件下,再生效果最好,再生率为98%,苯酚降解率为97%。与同一条件下MPPBPD体系相比,耦合体系再生率提高12%、苯酚降解率提高11%。分析了耦合再生体系对活性炭上苯酚的降解机理,结果显示,苯酚污染物在·OH、H₂O₂及O₃的氧化作用下被降解,活性炭恢复吸附性能。（5）分析对比了MPPBPD再生体系与耦合体系对活性炭性质的影响。结果表明,经MPPBPD再生体系与耦合体系再生后,活性炭表面的小颗粒附着物明显减少,再生前后的吸附等温线均属于I型,再生炭的孔结构参数均得到一定的恢复并且表面碱性基团和内酯基含量降低,酚羟基、羧基以及酸性基团含量增加。相比于MPPBPD再生体系再生炭,耦合体系再生炭表面的酸性基团含量更高且活性炭表面Fe³⁺含量增加。更多还原

【Abstract】 Activated carbon adsorption can effectively treat refractory organic wastewater,the conventional method of activated carbon adsorption alone has some disadvantages since the contaminants are not degraded but instead transferred to the solid phase from liquid phase.To reuse the activated carbon,an appropriate regeneration step is necessary to meet the environmental and economical requirements,which has motivated researchers to develop new methods for regeneration of activated carbon.In this work,aiming at the problems of low mass transfer efficiency of reactive species,high voltage corrosion of discharge plasma in water,and insufficient oxidation ability of reactive species such as H₂O₂ in the regeneration of activated carbon by dielectric barrier discharge plasma,a method of regeneration of activated carbon by multi-pin plate bubble pulse discharge（MPPBPD）plasma coupled with Fenton reaction is proposed to realize stable and efficient regeneration of activated carbon by low-temperature plasma.The specific research contents and results are as follows:（1）The MPPBPD regeneration system was constructed,and the influence of different experimental parameters on the physicochemical properties of MPPBPD plasma was investigated.The results showed that the structure type of the grounding electroed has no significant effect on the physicochemical characteristics of the reactor.The energy of the single pulse injection reactor increased with the decrease of electrode spacing,the conductivity of the solution and the increase of the air flow rate.With the increase of the carbon-water ratio in the discharge space,the energy of the single pulse injection reactor showed a trend of first increasing and then decreasing.The increase of the applied voltage and conductivity and the decrease of p H are conducive to the generation of reactive species H₂O₂ and O₃.（2）The regeneration performance of activated carbon when it is put between the high voltage electrode and the grounding electrode in MPPBPD system was studied.Moreover,the influence of this placement method on the surface morphology of activated carbon was analyzed.It was found that the regeneration rate increased and the energy efficiency decreased with the increase of voltage,the decrease of electrode spacing,the extension of regeneration time and the decrease of carbon-water ratio.With the increase of air flow rate and the decrease of the distance between activated carbon and high voltage electrode,the regeneration rate and energy efficiency can be improved.Under the condition of applied voltage of 12 k V,electrode spacing of 20 mm,conductivity of 750μS/cm,p H=6,air flow rate of 6 L/min,carbon-water ratio of 1:10,activated carbon distance of 0 mm from high voltage electrode and regeneration time of 30 min,the MPPBPD system has the best regeneration effect on activated carbon,with a regeneration rate of 126%and energy efficiency of 15.2 kg/k Wh and a phenol degradation rate of 86%,the mass loss rate of regenerated carbon is 4%,and the surface of the regenerated powdered activated carbon is uneven.（3）The regeneration performance of activated carbon in the MPPBPD system was studied when the activated carbon was located above the grounding electrode in the MPPBPD system.The influence of this placement method on the surface morphology of activated carbon was also analyzed.Results showed that under the condition of voltage of 14 k V,electrode spacing of 10 mm,conductivity of 750μS/cm,p H=6,air flow rate of 6 L/min,the carbon-water ratio of 1:10,activated carbon distance of 0 mm from high voltage electrode and regeneration time of 30 min,the MPPBPD system has the best regeneration effect on activated carbon,with a regeneration rate of 88%and energy efficiency of 7.5 kg/k Wh and a phenol degradation rate of88%.It is found that when the active carbon is put above the grounding electroed,little to no loss of regenerated carbon mass,and the surface of regenerated carbon was smooth,and complete.（4）The MPPBPD+Fenton regeneration system was constructed when the activated carbon is located above the grounding electrode in the MPPBPD.The influencing factors of the regeneration performance of the MPPBPD+Fenton regeneration system were explored.The regeneration effect of the MPPBPD regeneration system and the MPPBPD+Fenton regeneration system was compared.The experimental results showed that the regeneration rate of activated carbon first increased and then decreases with the increase of Fe²⁺concentration and p H.The regeneration rate increased with the increase of air flow rate,the extension of regeneration time and the decrease of carbon-water ratio.Under the condition of applied voltage of 14 k V,electrode spacing of 10 mm,Fe²⁺of 260 mg/L,conductivity of 1500μS/cm,p H=3,air flow rate of 6 L/min,regeneration time of 30 min,and carbon-water ratio of 1:10,the MPPBPD+Fenton regeneration system has the best regeneration effect on activated carbon,with a regeneration rate of 98%and a phenol degradation rate of 97%.Compared with the MPPBPD system under the same conditions,the combination of the MPPBPD and Fenton reaction can obviously improve the regeneration of activated carbon,with the regeneration rate increased by 12%and the phenol degradation rate increased by 11%.The degradation mechanism of phenol on activated carbon was analyzed,the experimental results showed that in the MPPBPD+Fenton regeneration system,phenol pollutants adsorbed on activated carbon were degraded under the reactive species of·OH,H₂O₂ and O₃,which restored the adsorption performance of activated carbon.（5）The effects of MPPBPD regeneration system and MPPBPD+Fenton regeneration system on the properties of activated carbon were compared and analyzed through the means of characterization.The results showed that after regeneration of the MPPBPD regeneration system and the MPPBPD+Fenton regeneration system,the small particle attachments on the surface of the activated carbon were reduced.The MPPBPD regeneration system and the MPPBPD+Fenton regeneration system have no effect on the adsorption isotherm of activated carbon,and N₂ adsorption isothermal both belong to the I-type adsorption isotherm.The pore structure parameters of the regenerated carbon are restored to a certain extent compared with saturated carbon.After the treatment of MPPBPD regeneration system and MPPBPD+Fenton regeneration system,the alkaline group and lactone group content of regenerated carbon decreased,and the content of phenolic hydroxyl,carboxyl group and acid group increased.Compared with the regenerated carbon in MPPBPD regeneration system,and the acid group content of regenerated carbon surface in MPPBPD+Fenton regeneration system was higher.The surface of activated carbon increased from 0.63%of virgin carbon to 2.04%of treated by the MPPBPD+Fenton regeneration system.更多还原