氧化型聚硅酸铁处理腈纶废水的试验研究

发布时间：2018-03-23 06:17

本文选题：氧化型聚硅酸铁　切入点：制备　出处：《河北工程大学》2015年硕士论文　论文类型：学位论文

【摘要】：腈纶废水成分复杂,是一种典型的难降解有机工业废水,即便生化处理后出水中仍含有多种难降解易引发生物毒害作用的有机物,随着排放标准的日益严格,亟需先进的处理技术对该类废水进行处理。混凝沉淀工艺因其高效、价格低廉,操作简单,管理方便等特点被认为是性价比较高的深度处理技术,成为腈纶废水深度处理工艺中的首选工艺。对于难降解有机物,传统混凝剂的去除能力有限,出水中的残余化学需氧量(COD)难以达标排放。为此,本研究针对腈纶废水生化出水中的难降解有机物,研制一种氧化型聚硅酸铁(PSF)无机复合高分子混凝剂,研究了该混凝剂的优化制备、最优反应条件,在此基础上考察了混凝剂结构、混凝效率以及絮体性质,探究了混凝剂作用机理,为将该混凝剂应用于腈纶废水深度处理工艺中奠定了理论基础。主要研究内容及结果如下:用硫酸亚铁、硅酸钠、氯酸钠、硫酸等原料制备了氧化型聚硅酸铁混凝剂,并优化得到了最佳制备条件:混凝剂初始p H为1.67,氯酸钠用量为8g/L,Fe/Si摩尔比为1.3,陈化时间为3d,在此优化基础上,采用SEM、TEM技术对混凝剂形貌进行了表征,结果发现混凝剂中聚硅酸和铁并不是单纯的混合,而是两者之间经过复杂的聚合反应生成了非晶体、无规则的高分子氧化型聚硅酸铁。以腈纶废水生化出水为处理对象,系统考察了反应条件原水p H、混凝剂投加量、慢搅时间对CODcr去除率的影响,优化得到了最佳反应条件:原水p H为7,混凝剂投加量为1.548mmol/L,慢搅时间为20min,此时CODcr去除率达到了43.00%,DOC去除率达到了36.80%,TN去除率达到了18.00%,浊度去除率达到了97.37%,各指标达到了《污水综合排放标准》(GB8978-1996)中腈纶废水排放一级标准,三维荧光扫描结果发现:混凝剂可有效处理腈纶废水中腐殖质类物质、类蛋白类物质以及UV腐殖质类物质。混凝效果优于传统的聚合铁和聚硅酸硫酸铝。研究混凝剂混凝作用机理:采用p H计、小角激光散射技术研究混凝剂陈化过程中的p H变化以及絮体性质,发现p H变化规律是聚硅酸和铁综合作用的结果;絮体的生长速度快、絮体强度高、复原能力强,对于腈纶废水生化出水特定水质条件,混凝机制以电中和作用为主。
[Abstract]:Acrylonitrile wastewater is a typical organic industrial wastewater with complex composition. Even after biochemical treatment, the effluent still contains a variety of organic compounds that are difficult to degrade and easily lead to biological toxicity. With the increasingly stringent discharge standards, Because of its high efficiency, low price, simple operation and convenient management, coagulation and sedimentation process is considered to be a high performance and price ratio advanced treatment technology. For refractory organic matter, the removal capacity of traditional coagulant is limited, and the residual COD in effluent is difficult to discharge. In this paper, an oxidized polysilicate iron silicate (PSF) inorganic composite polymer coagulant was developed for the refractory organic matter in the biochemical effluent of acrylic fiber wastewater. The optimum preparation and reaction conditions of the coagulant were studied. On this basis, the coagulant structure, coagulation efficiency and flocculation properties were investigated, and the mechanism of coagulant action was explored. The main research contents and results are as follows: the oxidized polysilicate ferric silicate coagulant was prepared with ferrous sulfate, sodium silicate, sodium chlorate, sulfuric acid and other raw materials. The optimum preparation conditions were obtained as follows: the initial pH of coagulant was 1.67, the dosage of sodium chlorate was 1.3 g / L Fe / Si molar ratio, and the aging time was 3 days. On the basis of the optimization, the morphology of coagulant was characterized by means of SEMT-TEM. The results showed that polysilicic acid and iron in coagulant were not a simple mixture, but formed amorphous, irregular polymeric oxidized polysilicate ferric acid through complex polymerization reaction between them. The biochemical effluent of acrylic fiber wastewater was treated as the object. The effects of reaction conditions, raw water pH, coagulant dosage and slow stirring time on the removal rate of CODcr were systematically investigated. The optimum reaction conditions were obtained as follows: raw water pH was 7, coagulant dosage was 1.548 mmol / L, slow stirring time was 20 minutes, and the removal rate of CODcr reached 43.00 and reached 36.80% TN removal rate, and turbidity removal rate reached 97.37, and each index reached 97.37. The first class standard for the discharge of acrylic fiber wastewater in the Integrated Wastewater discharge Standard (GB8978-1996) was introduced. The results of three dimensional fluorescence scanning showed that the coagulant could effectively treat humus in acrylic fiber wastewater. Protein-like substances and UV humus substances. The coagulation effect is superior to that of traditional polymeric iron and polysilicate aluminum sulfate. The change of pH and the properties of flocs during coagulant aging were studied by small-angle laser scattering technique. It was found that the variation of pH was the result of the comprehensive action of polysilicic acid and iron, and the flocs had fast growth rate, high floc strength and strong resilience. For the specific water quality conditions of biochemical effluent of acrylic fiber wastewater, the coagulation mechanism is mainly electric neutralization.
【学位授予单位】：河北工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X783.4

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