【作者】 孙翠珍；

【导师】 岳钦艳；

【作者基本信息】 山东大学 ， 环境工程， 2012， 博士

【摘要】 混凝沉淀法工艺简单、经济高效、操作方便,因此被广泛应用于水和废水处理中。絮凝剂性能的好坏关键性地决定了混凝效果的优劣和混凝工艺运行费用的高低。为了提高无机絮凝剂的絮凝效果,降低有机絮凝剂的水处理成本,在实际应用中可以将两种或两种以上具有混凝功效的无机和有机物质经过加工,生成新的复合絮凝剂产品。近年来,研发各种无机-有机复合型絮凝剂,成为了水处理药剂开发的热点。本文在综合国内外大量相关文献的基础上,以聚合氯化铝铁(PAFC)和二甲基二烯丙基氯化铵均聚(PDMDAAC)为原料制备出新型聚合氯化铝铁-二甲基二烯丙基氯化铵均聚物复合絮凝剂(PAFC-PDMDAAC),并利用现代先进的检测方法,对制备的复合高分子絮凝剂的荷电情况进行了评估。同时研究了在模拟地表水和染料废水处理中PAFC-PDMDAAC中无机成分和有机成分配比(P)、无机组分碱化度(B)、有机组分特性粘度(η)、原水pH值对该复合絮凝剂的混凝性能、混凝机理及混凝动力学过程的影响。本文还对PAFC-PDMDAAC复合絮凝剂所形成的絮体的物理特性如絮体强度、恢复能力和分形维数进行了深入研究,揭示复合絮凝剂无机和有机组分之间的相互作用。该研究对于聚合氯化铝铁-有机复合絮凝剂的研制开发和应用提供了理论指导。主要研究内容及结论如下：1.利用Zetasizer3000HSA型zeta电位仪测定了复合絮凝剂PAFC-PDMDAAC的zeta电位,研究了絮凝剂表面的电荷特性。结果表明PAFC与PDMDAAC复合后,其表面电荷和zeta电位明显升高,对带负电荷的胶粒的电中和能力增强。此外,PAFC-PDMDAAC的表面电荷和zeta电位随着P值的降低、η的增大而增大,B=1.0的PAFC-PDMDAAC的表面电荷和zeta电位明显高于B值过低或过高的PAFC-PDMDAAC。2.采用PAFC-PDMDAAC、PAFC单独投加、PAFC和PDMDAAC以不同次序先后投加四种方式对模拟地表水和模拟分散黄染料废水进行混凝实验。研究表明：①在处理模拟地表水时,投加方式对浊度的去除效果影响不大。但是,PAFC-PDMDAAC对有机物的去除效果明显优于PAFC、PAFC+PDMDAAC和PDMDAAC+PAFC,而且投加量较低,在达到相同的有机物去除率的情况下,复合絮凝剂的投加量比PAFC单独投加时约降低了25%-35%,从而大大降低了所需的药剂成本。此外,PAFC和PDMDAAC的联合投加,提高了絮凝剂的电中和能力。与PAFC+PDMDAAC相比,PAFC-PDMDAAC的电中和能力较弱,但其吸附架桥和网捕作用明显增强；与PDMDAAC+PAFC相比,复合絮凝剂的电中和能力、吸附架桥和网捕作用都明显增强；②在处理分散染料废水时,四种投加方式的絮凝剂对分散染料脱色率的高低顺序为PAFC-PDMDAAC>PDMDAAC+PAFC>PAFC+PDMDAAC>PAFC。四种投加方式的絮凝剂电中和能力的强弱顺序为PAFC+PDMDAAC>PAFC-PDMDAAC>PDMDAAC+PAFC>PAFC。复合絮凝剂PAFC-PDMDAAC对分散黄的混凝机理除了电中和作用外,吸附架桥和网捕作用起着重要的作用。从处理地表水和染料废水来看,PAFC-PDMDAAC可以发挥PAFC和PDMDAAC的协同作用,较传统絮凝剂具有一定的优势。3.通过对模拟地表水和模拟分散黄染料废水的混凝实验,考察了絮凝剂的(Al+Fe)/PDMDAAC质量比(P)、无机组分的B值和有机组分的η值对PAFC-PDMDAAC混凝效果和zeta电位的影响,探讨了复合絮凝剂对模拟地表水和模拟分散染料废水的混凝机理。结果表明：①处理模拟地表水时,P=10的混凝效果明显优于P值过低或过高的PAFC-PDMDAAC,B=1.0的混凝效果明显优于B值过低或过高的PAFC-PDMDAAC,提高η值,可以提高PAFC-PDMDAAC对浊度和DOC的去除效果；②处理模拟分散染料废水时,P值越低,B值和η值越高,PAFC-PDMDAAC的脱色效果越好。对于PAFC-PDMDAAC来说,电中和作用、吸附架桥和网捕作用是其主要的混凝机理,电中和能力随着P的降低,η值的增大而增强。4.通过对模拟地表水和模拟分散黄染料废水的混凝实验,考察了原水pH值对PAFC-PDMDAAC混凝效果的影响。研究表明：①处理模拟地表水时,原水pH值对地表水浊度的去除效果影响不大,但对有机物去除效果影响较大。原水碱性越强,PAFC-PDMDAAC对UV254和DOC的去除效果越差。在pH=5.5的条件下,其对有机物的去除效果最佳；②处理模拟分散染料废水时,PAFC-PDMDAAC具有较宽的pH适宜范围。在pH为6-9时,复合絮凝剂对分散黄的去除率达96%以上,脱色效果最佳。5.利用光散射颗粒分析仪PDA2000在线监测了PAFC-PDMDAAC的混凝动力学过程,研究了处理模拟染料废水的混凝过程中PAFC-PDMDAAC的絮体特性。结果表明：在处理分散黄模拟染料废水的过程中,与PDMDAAC、PAFC相比,复合絮凝剂PAFC-PDMDAAC的最终絮体粒度大大提高,絮体差异性减小,这将最终提高其脱色效果；投加量较低时,PFC-PDMDAAC复合混凝剂中有机部分含量越高,最终絮体粒度越大,絮体差异性越小,脱色效果越好；投加量较高时,有机成分含量越高,絮体差异性越大,絮体大小不均匀,但由于最终絮体粒度较大,导致脱色效果越好；PAFC-PDMDAAC的预水解程度越高,絮体差异性越大,但由于吸附架桥和网捕作用增强,最终絮体粒度较大,因此脱色效果较好；在pH值为6-7.5时,PDMDAAC、PAFC、PAFC-PDMDAAC所形成絮体最终粒度较大,沉降性能较好,从而混凝效果较好；当PAFC-PDMDAAC作为絮凝剂时,其对染料废水的处理效果受到水质波动影响小。6利用光散射颗粒分析仪PDA2000在线监测了PAFC-PDMDAAC的混凝动力学过程,研究了处理模拟地表水的混凝过程中PAFC-PDMDAAC的絮体特性。处理模拟地表水时,与PAFC相比,复合絮凝剂PAFC-PDMDAAC的使用可以大幅提高絮体的生长速度,缩短絮凝剂与污染物反应时间,提高所形成絮体的最终粒度,提高沉降速度,从而提高混凝效果。此外,PAFC-PDMDAAC中的(Al+Fe)/PDMDAAC质量比(P)、无机组分的B值、有机组分的η值和原水pH值对的絮体生长特性均有一定的影响。在低P值(4)、高B值(1.5)、高η值(1.21dL/g)和酸性(pH=5.0)条件下,絮体生长速度快,形成的絮体最终粒径大,混凝效果好。在絮体破碎阶段,PAFC-PDMDAAC所生成絮体的中位粒径在施加剪切力瞬间急剧下降,随着剪切时间的增加,粒径缓慢降低。破碎的絮体可以聚集再生,但再生成絮体的粒径远远小于破碎前的粒径。施加的剪切力的时间越长,施加的剪切力越大,絮体破碎程度越大。提高P值、降低B值、提高η值、缩短剪切时间和减小剪切力可以在一定能够程度上提高絮体强度,降低P值、降低B值、提高η值、缩短剪切时间和增大剪切力可以在一定能够程度上提高絮体恢复能力。此外,在酸性条件下具有较高的絮体强度和恢复能力。在有机成分的含量高(降低P值)、高B值、高η值和酸性条件下,PAFC-PDMDAAC所形成的絮体的分形维数较大,具有较高的密实度。综上所述研究,本文系统地探讨了复合絮凝剂PAFC-PDMDAAC对模拟染料废水和模拟地表水的混凝效果、混凝性能、混凝机理和絮体特性,结果表明,PAFC-PDMDAAC是一种更为高效经济的絮凝剂。本论文的研究为聚合铝铁复合絮凝剂的研制和应用奠定理论基础。更多还原

【Abstract】 Coagulation sedimentation process was widely applied in water and wastewater treatment because of its advantages:simple process, low cost, high coagulation removal and easy operation. Coagulant properties are the key factors which related to the coagulation efficiency and the operating cost. In order to improve the coagulation efficiency and reduce the operating cost, two or more inorganic and organic coagulants were used to prepare the new composite coagulant. In recent years, the inorganic-organic composite coagulant was the hot development area of water treatment agents.Synthesizing a number of references and literature, a composite flocculant, PAFC-PDMDAAC, was prepared by combining polymeric aluminum ferric chloride (PAFC) with polydimethyldiallylammonium chloride (PDMDAAC). Zeta potentials of PAFC-PDMDAAC were evaluated by modern advanced method. In synthetic surface water treatment, the effect of (Al+Fe)/PDMDAAC mass ratio (P), basicity (B) of PAFC, intrinsic viscosity (η) of PDMDAAC and pH value on the flocculation efficiency, flocculation mechanism and coagulation dynamics were investigated. Moreover, the floes properties, such as floe strength, the regrowth ability of broken floes and the fractal dimension of floes, were discussed. The correlation between inorganic and organic component in the composite flocculant was revealed. The research results provide theoretical guidance for the preparation and application of PAFC-PDMDAAC.The main conclusions are as follows:1. The zeta potential and charged characteristics of PAFC-PDMDAAC were determined using a Zetasizer3000HSA analyzer. The results showed that the surface charge, the zeta potential and the charge neutrality of PAFC-PDMDAAC were higher than that of PAFC. Moreover, the surface charge and the zeta potential of PAFC-PDMDAAC increased with the decrease of P and increase of η value. PAFC-PDMDAAC with B=1.0had the highest surface charge. 2.Coagulation experiments were conducted by treating synthetic surface water and disperse yellow dying wastewater using four dosing way,such as addition of composite coagulant PAFC-PDMDAAC,addition of PAFC,successive addition of PAFC and PDMDAAC.①In treating synthetic surface water,dosing way had little effect on the turbidity removal efficiency. Compared with PAFC, PAFC+PDMDAAC and PDMDAAC+PAFC, PAFC-PDMDAAC gave higher organic matter removal effi ciency and lower optimal dosage.Further,PAFC-PDMDAAC showed weaker charge neutralization ability but much stronger absorption/bridging and enmeshment ability than PAFC+PDMDAAC, and showed stronger charge neutralization, absorption/bridging and enmeshment ability than PDMDAAC+PAFC.②In treating disperse yellow dying wastewater, the order of the decolorization rate was PAFC-PDMDAAC>PDMDAAC+PAFC>PAFC+PDMDAAC>PAFC.Compared with PAFC,PAFC+PDMDAAC and PDMDAAC+PAFC,PAFC-PDMDAAC gave lower optimal dosage.The order of the charge neutralization was PAFC+PDMDAAC>PAFC-PDMDAAC>PDMDAAC+PAFC>PAFC.In coagulating disperse yellow, charge neutralization;bridging and enmeshment were the main coagulation mechanisms for PAFC-PDMDAAC.Consequently,PAFC-PDMDAAC achieved good performance by synergic effect of PAFC and PDMDAAC during surface water treatment.3. The flocculation efficiency of PAFC-PDMDAAC with different (Al+Fe)/PDMDAAC mass ratio(P),basicity(B)of PAFC and intrinsic viscosity(η)of PDMDAAC was studied in the treatment of synthetic surface water and disperse yellow dying wastewater,and the zeta potential of the flocs was also investigated,which explained the flocculation mechanism.①In the trealment of synthetic surface water, PAFC-PDMDAAC with intermediate P(P=10),intermediate B(B=1.0)and higher η (η=1.21dL/g)gave higher coagulation efficiency.②In the treatment of disperse yellow dying wastewater,PAFC-PDMDAAC with lower P(P=4),higher B(B=1.5) and higher η(η=1.21dL/g)gave higher decolorization efficiency.The charge neutralization,adsoyption/bridging and enmeshment ability of PAFC-PDMDAAC played a role for the coagulation mechanisms. The charge neutralization ability of PAFC-PDMDAAC was stronger with the decrease of P value and the increase of η value of PDMDAAC.4. The effect of pH on the flocculation efficiency of PAFC-PDMDAAC was studied in the treatment of surface water and disperses yellow dying wastewater.①In the treatment of synthetic surface water, pH value had lower effect on the turbidity removal and higher effect of the organic matter removal. The UV254and DOC removal efficiencies decreased with the increase of alkalinity. The organic matter removal efficiency is the highest when pH value of the raw water is5.5.②In the treatment of disperse yellow dying wastewater, the appropriate pH range of PAFC-PDMDAAC was wider. The decolorization efficiency is the highest when pH value of the raw water is6-9.5. The laser scatter analyzer PDA2000was used to on-line monitor the floe properties of PAFC-PDMDAAC. In the treatment of disperse yellow dying wastewater, the larger average floe size (Ratio) and lower Relative Standard Deviation (RSD) were achieved by PAFC-PDMDAAC compared with PDMDAAC and PAFC. Therefore, the dying removal efficiency of PAFC-PDMDAAC was better than that of PDMDAAC and PAFC. At lower dosage, the Ratio was increased and the RSD was decreased with the organic regent contents increasing. At higher dosage, the Ratio and the RSD was increased with the organic regent contents increasing. When pH was6-7.5, the Ratio of PDMDAAC、PAFC and PAFC-PDMDAAC were larger.6. In the treatment of synthetic surface water, faster floe growth velocity, shorter reaction time, larger average floe size, faster sedimentation velocity and better flocculation efficiency were achieved by PAF-DMDAAC compared with PAFC. Besides, the effect of (Al+Fe)/PDMDAAC mass ratio (P), B, η and pH values on the floe aggregation was investigated. Faster floe growth, larger average floe size and better flocculation efficiency were achieved by PAFC-PDMDAAC (P=4, B=1.5, η=1.21dL/g and pH=5.0). In breakage phase, the median equivalent particle diameter under all cases declined significantly and then followed by a gradual drop when the stirring speed was increased from40to200rpm. When the stirring rate was decreased to40rpm, the flocs began to regrow again. However, the flocs could not regrow to their previous sizes. The floe breakage degree decreased with the increase of the shear time and shear forces. Higher P, lower B, higher η value, shorter shear time and lower shear force could improve the floe strength. Lower P, lower B, higher η value, shorter shear time and higher shear force could increase regrowth ability in a certain extent. Moreover, PAFC-PDMDAAC gave higher floe strength and regrowth ability in the acid condition. Moreover, the floes formed by PAFC-PDMDAAC with lower P, higher-η and B value had higher fractal dimension and more compact structure. In addition, the floes formed in the acid condition were more compact.The above research studied the flocculation efficiency, flocculation behavior, coagulation mechanisms and floes properties of PAFC-PDMDAAC in the treatment of surface water, indicating that the composite flocculant was highly efficient and economical coagulant. This research provides fundamental and theoretical basis for the developing and practical application of PAFC-PDMDAAC更多还原