【作者】 刁伟力；

【导师】 刘淼；

【作者基本信息】 吉林大学 ， 环境科学， 2006， 硕士

【摘要】 有机废水由于其产生量大,尤其是一些制药及化工废水,浓度高,并常含高浓度的有毒有害物质,对生物体产生毒性,不易自然降解以及易在生物体内积累等特性,而成为水环境中一类重要的污染物,对环境和人体健康产生严重的危害作用。本文研究了电解法产生自由基的一些规律,并以含酚废水为例,讨论了用电解法产生自由基处理含酚废水的一些影响因素。羟自由基是许多自由基氧化反应的反应主体,利用它极强的氧化能力处理有机废水,可使废水的化学需氧量（COD）值大大降低,达到水处理的目的。水杨酸（2-HBA）的羟基化产物2,5-二羟基苯甲酸（2,5-DHBA）可以作为羟自由基产生的指示剂。在利用2-HBA及其羟基化产物2,5-DHBA研究羟自由基在电极电解过程中的形成规律中,用以钛网为基体,锡、锑为中间层的二氧化铅电极在高频交流电源下电解2-HBA的水溶液,然后利用高效液相色谱（HPLC）检测分析2-HBA和2,5-DHBA的浓度变化。结果表明:pH值和频率对羟自由基的产率影响明显,溶液碱性条件要优于酸性条件,电源高频情况要优于低频情况,即碱性和高频条件更有利于羟自由基的生成。同时利用该电解装置进行苯酚降解实验表明,利用电解法产生的自由基处理有机废水效果明显。在本文讨论的因素中,高pH值,高温有利于苯酚的降解,而低pH值,低温以及CO₃^2-、PO₄^3-的存在不利于苯酚的降解,Cl^-的存在虽有利于酚的去除,但却影响溶液中有机物总的去除量。更多还原

【Abstract】 Wastewater with organic pollutants is one of the most harmfulsubstances, because its characteristics of big volume, highconcentration, noxious to living beings, hard degradable by naturalprocesses and easy accumulated in bodies. Forming law of hydroxylradical during electrolysis process was discussed in this paper. Thentook wastewater with phenol for example, we described some factorsthat affected forming of hydroxyl radical, which further affectedphenol degradable effect.Hydroxyl radical is the main specie of many free radical oxidationreactions. The strong oxidation ability of hydroxyl radical can be usedto oxidize organic substances and other impurities in water, decreasesthe Chemical Oxygen Demand (COD) value and achieves the goal ofwater treatment. Aromatic hydroxylation from the reaction betweenhydroxyl radical and salicylate or its related compounds has been oftenutilized as a marker for the generation of hydroxyl radicals. We hadinvestigated several technical aspects of applying this method to studyhydroxyl radical production during electrolysis using the salicylicacid(2-HBA) to form 2,5-dihydroxybenzoic acid(2,5-DHBA).Aqueous solution of 2-HBA was electrolyzed by Ti-base Lead DioxideElectrode regard Sn, Sb as the intermediate level, then the solutioncontaining 2-HBA and 2,5-DHBA was analyzed by High PerformanceLiquid Chromatography(HPLC) with fluorescence detection .It wasconcluded that the oxidation of 2-HBA to 2,5-DHBA could be areliable and accurate indicator for the formation of hydroxyl radical ifthe experiments are well designed to avoid potential pitfalls associatedwith technical difficulties of the method. The results show that the pHvalue and frequency play important roles in the producing rate ofhydroxyl radical. High pH value is better than low pH value, also ishigh frequency than low frequency. The experiment of phenoldegradation was done at the same time;it indicated that using thehydroxyl radical produced by electrolysis to treat organic wastewatershave good effect.Because the degradation of phenol was achieved by hydroxylradical which formed by electrolysis, factors which affect hydroxylradical forming affect phenol degradation, too. Within the factorsdiscussed in this paper, high pH, high temperature was propitious tophenol degradation. On opposite, low pH, low temperature, theexisting of CO32-and PO43-went against phenol degradation. Theexisting of Cl-was propitious to phenol degradation, but went againstCOD removal.Through comparison of different initial phenol concentrations, wefound electrolysis efficiency was increased along with increasing ofinitial phenol concentrations. So this method was appropriate aspretreatment to other methods. Take it as advanced treatment wassuitable, too. Subsequently, the degradation of true wastewaterindicated that using this method to treat organic wastewaters has greatrealistic meanings and wide application prospects.更多还原