【作者】 莫一平；

【导师】 马淳安；

【作者基本信息】 浙江工业大学 ， 应用化学（专业学位）， 2011， 硕士

【摘要】 生化处理是工业有机废水处理的首选方法,但对于难降解的有机废水必须经过预处理提高其可生化性才能进行生化处理。Fenton试剂氧化法作为一种高级氧化技术在难降解有机废水处理中得到广泛的应用,其中的电Fenton法因能现场发生Fenton试剂而最具工业化应用潜力,但由于它工作电流小,电流效率低,电极易受污染等问题难以在真正的工业化中得到应用。本文提出了一种不同于电Fenton法的Fenton试剂现场发生技术,有望实现工业化应用。本文提出了一种独立于废水之外的H2O2现场制备技术,借鉴氧阴极还原法制备碱性H2O2的技术开发出低碱比低离子强度碱性H2O2的电合成技术,以适应Fenton氧化所需的弱酸性环境。采用2-乙基蒽醌改性的气体扩散电极作为氧还原阴极,以阳离子交换膜为隔膜,采用酸性阳极液膜过程控制阴极液的碱度,在电流密度为750A·m-2,空气流量为理论供氧量的1.3倍并将阳极产生的氧气返回气室,在室温条件下循环电解8小时,在pH为12的2.5wt%Na2SO4溶液中得到了碱比为0.23:1,质量浓度为1.5%的碱性H2O2溶液。本文还将铁炭微电解技术引入到Fe2+现场发生技术中,以生物素生产废水作为难降解有机废水的代表,通过铁炭微电解反应器可以快速地在废水中引入所需的Fe2+。在进水pH为3.5,Fe:C=1:1,循环反应3小时,实际停留时间为1小时,可以在废水中引入10mmol·L-1左右的Fe2+,同时去除部分COD。铁炭微电解技术与低碱比低离子强度H2O2电合成技术共同组成Fenton试剂现场发生技术。本文还研究了采用Fenton试剂现场发生技术对生物素生产废水进行预处理的工艺条件。经过单因素的影响研究确定了优选的操作条件为:铁炭微电解进水pH为1.5,微电解接触时间为1小时,微电解出水无需调整pH,以连续滴加的方式投加25mmol·L-1的现场制备的H2O2,在室温下反应1小时,生物素生产废水的COD去除率达50%以上。通过模拟好氧生化处理证明,采用Fenton试剂现场发生技术预处理后的生物素生产废水可生化得到了大大提高。在小试研究的基础,本文还进行了生产现场的中试研究,设计并制作了低碱比低离子强度碱性H2O2的中试装置和铁炭微电解的中试装置,同时建设了以Fenton试剂现场发生技术作为预处理技术的中试处理线,经三十天的连续运行结果看,出水水质稳定,与原有的处理工艺相比,无论是出水水质还是处理速度都得到了明显地提升,出水水质达到了富阳当地的纳管标准。中试研究结果证明,Fenton试剂现场发生技术是难降解有机废水预处理的有效技术手段,完全具备了实用化的可能,应用前景广阔。更多还原

【Abstract】 Biological treatment is the preferred method for the industrial organic wastewater treatment,but refractory organic wastewater must be pretreated to improve its biodegradability before biochemical processing.As an advanced oxidation processes,Fenton’s reagent oxidation processes is widely used in the refractory organic wastewater treatment.And electro-Fenton method has the greatest potential for industrial application because it could generate Fenton’s reagent on site,but low working current,low current efficiency and electrode vulnerable contaminated result in that it is difficult to apply in real industrial applications.This paper proposed a method different from the electro-Fenton method,in situ generation of Fenton’s reagent,which was expected to achieve the purpose of industrial applications.This paper presented a method for in situ preparation of H2O2 which was independent of the wastewater,low alkali-ratio and low ionic strength alkaline H2O2 electro-synthesis method was developed by drawing on the technique of cathodic reduction of oxygen to prepare alkaline H2O2,adapting to the required weak acidic environment of Fenton’s reagent oxidation processing.Gas diffusion electrode modified by 2-ethyl anthraquinone as oxygen cathode reduction,cation exchange membrane as the diaphragm,the alkalinity of the cathode solution was controlled by acid anodic membrane process.When the current density was 750A·m-2,air flow rate was 1.3 times the amount of the theoretical oxygen and oxygen produced on anode return to the air chamber,after cyclic electrolysis for 8 hours at room temperature,alkaline H2O2 solution which alkali ratio was 0.23,the mass concentration was 1.5%was obtained in the 2.5wt%Na2S04 solution at pH 12.This article also introduced iron-carbon micro-electrolysis method for in situ generation of Fe2+,which could be quickly introduced into the biotin production wastewater as a representative of refractory organic wastewater through the iron-carbon micro-electrolysis reactor.After 3 hours cyclic reaction and 1 hour actual residence,under the conditions of initial pH 3.5 and Fe:C=1:1,10mmol·L-1 Fe2+ was introduced into the wastewater,while part of the COD was removed.Iron-carbon micro-electrolysis processing and low alkali-ratio and low ionic strength alkaline H2O2 electro-synthesis processing formed the method for in situ generation of Fenton’s reagent.The processing conditions about the pretreatment of biotin production wastewater using in situ generated Fenton’s reagent was studied.After considering influence of a single factor,optimal operating conditions were chosen:pH of iron-carbon micro-electrolysis inffluent was 3.5,micro-electrolysis contact time was 1 hour,and pH of micro-electrolysis effluent need not adjust,25 mmol·L-1 H2O2 preparated on site were added by a continuous dropping manner,the COD removal rate of the biotin production wastewater was more than 50%after reacting 1 hour at room temperature.Simulated aerobic biological treatment showed that the biodegradability of the biotin production wastewater pretreated by in situ generated Fenton’s reagent had been greatly enhanced.Based on the laboratory studies,this paper also conducted a pilot scale study on the production site,designed and produced the pilot scale devices of the low alkali-ratio and low ionic strength alkaline H2O2 and the iron-carbon micro-electrolysis,constructed the pilot processing line that in situ generated Fenton’s reagent used for pretreatment of biotin producton wastewater.After thirty days continuous operation,the results showed that the quality of effluent was stability,and compared with the original treatment process,whether quality of the effluent or processing speed had been significantly improved,reaching the local sewer standard of Fuyang.The results obtained from pilot scale stueies indicated that the method for in situ generation of Fenton’s reagent was an effective technical means for the pretreatment of the refractory organic wastewater,fully equipped with the practical possibility and broad application prospects.更多还原