【作者】 李雪；

【导师】 梁文艳；

【作者基本信息】 北京林业大学 ， 环境科学与工程， 2018， 硕士

【摘要】 腐殖酸(HA)大量存在于垃圾渗滤液,煤炭废水以及污泥中,严重影响水体水质,影响重金属的迁移和去除;HA组成中含有大量的高活性芳香烃结构,分子量大,通过普通的生物降解法难以去除。本文通过硬模版法制备了平均孔径为4.29 nm的有序介孔碳粉末(POMC),并首次将POMC制备成柱状的有序介孔碳颗粒(GOMC,Φ×H=4×3-6 mm)作为粒子电极填充到连续流三维电极反应器中,用于降解腐殖酸大分子污染物。通过POMC对HA的吸附能力选择硬模版SBA-15的制备条件,实验发现最佳的制备条件为:HCl浓度为2.5 mol/L,静置时间为24 h,水热反应时间48 h,焙烧时间2h。SEM、TME的结果表明最优条件下制备的POMC成功复制了硬模板SBA-15的外貌以及有序的孔道结构;通过N2吸附脱附曲线,发现POMC的平均孔径为4.29 nm,比表面积为980.2 m2/g,通过粒度分布仪测定POMC的平均粒度为7.99 μm。吸附等温线何吸附动力学结果表明,POMC和GOMC粒子电极对HA的吸附主要是通过孔扩散模式进行,通过Langmuir等温线拟合的吸附量分别为111.3 mg/g,53.7 mg/g。研究电化学参数对腐殖酸降解效果的影响发现当电流为0.2 A,0.01 mol/L的Na2S04作为电解质溶液,进水的初始pH为7.0,水力停留时间为130 min,此时HA的UV254和COD去除率达到95.3%和86.2%,矿化率达到62.7%,出水HA对小球藻的生长抑制率从68%降低到15%。出水HA的紫外可见光谱、三维荧光谱、傅立叶红外变换光谱、气相色谱-质谱的结果表明在HA在电化学降解过程中主要是破坏芳香环(C=C结构),降解为产物主要为饱和的烷烃、有机酸小分子的富里酸类物质。揭示了 GOMC三维反应去除/降解HA是吸附过程和电化学降解过程共同的作用;HA的间接氧化的氧化剂主要是通过·OH和SO4·-的作用。电化学测试表明,中性条件以及低浓度的电解质浓度环境时,POMC具有较高的析氧过电位,减少析氧副反应发生,提高电流效率,同时循环伏安曲线的测定发现,腐殖酸在介孔碳表面同时发生直接氧化和还原反应。更多还原

【Abstract】 Humic acid(HA)is widely found in landfill leachate,coal wastewater and sludge,which seriously affects water quality and the migration of heavy metals.HA contains a large number of highly active aromatic hydrocarbons with a large molecular weight.It is difficult to remove by ordinary biodegradation.In this paper,an ordered mesoporous carbon powder(POMC)with an average pore size of 4.29 nm was prepared by hard template method.POMC was prepared into a columnar ordered mesoporous carbon particle(GOMC,Φ×H=4×3-6 mm)for the first time and used for degradation of humic acid macromolecular pollutants.The effects of electrochemical conditions on the degradation of HA by GOMC particle electrode were studied.The toxicity evaluation of HA degradation product was studied.The degradation product of HA by GOMC particle electrode was proposed,and the degradation mechanism of HA in GOMC three-dimensional electrocatalytic reaction system was discussed.The electrochemical characteristics of POMC was studied,which provided theoretical support for the treatment of macromolecular organic pollutants in practical engineeringThe effects of electrochemical degradation parameters such as current and hydraulic retention time(HRT)were investigated,and the degradation mechanism of HA was explored as well.The results indicated that the UV254 degradation efficiency of HA,chemical oxygen demand(COD),and total organic carbon(TOC)reached 95.3%,86.2%and 62.7%,respectively,under initial HA of 100 mg/L,current of 0.2 A and HRT of 130 minThe results of UV-vis spectroscopy,three-dimensional fluorescence spectroscopy,Fourier transform infrared spectroscopy,and gas chromatography-mass spectrometry of the effluent HA showed that the aromatic ring(C=C structure)was mainly destroyed during the electrochemical degradation of HA,and the product was degraded into saturated alkanes,organic acids,small molecules of fulvic acids.It is revealed that the removal/degradation of HA by GOMC three-dimensional reaction was the combined action of adsorption process and electrochemical degradation process.The electrochemical tests show that under neutral conditions and low concentrations of electrolytes,POMC has a high oxygen evolution overpotential,reducing the occurrence of oxygen evolution side reactions,and improving current efficiency.At the same time,the cyclic voltammetry curves indicated that the reactions of HA on the OMC materials surface included both direct oxidation and direct reduction.更多还原