【作者】 郑怀礼；

【导师】 龙腾锐；

【作者基本信息】 重庆大学 ， 市政工程， 2003， 博士

【摘要】 絮凝剂是重要的水处理材料，是絮凝法水处理技术的关键和基础。目前，国内外主要使用铝盐絮凝剂。由于铝盐絮凝剂效率较低且存在环境问题，在我国及世界，絮凝剂的研究与应用水平都有待创新和提高。目前,世界上絮凝剂的研究主要向着高效低耗、安全无害、无二次污染方向发展。研究高效低耗、安全无害的铁系复合絮凝剂属于絮凝科学领域的研究前沿之一。本研究利用钛白副产物FeSO4·7H2O为原料,研究了聚铁基复合絮凝剂的制备与絮凝作用机理，为研究和应用铁系复合絮凝剂作了有益的探索和努力。主要研究内容有： 聚铁基无机高分子复合絮凝剂聚硅硫酸铁（PFSiS）的研究；聚铁基淀粉改性无机/有机复合絮凝剂（PFS-CSM）的研究。PFSiS和PFS-CSM的研究都包括了制备研究、絮凝作用机理研究、絮凝效果研究、水处理应用试验等。本研究中，制备PFSiS聚铁基复合絮凝剂的主要研究内容有：①、以钛白生产副产物七水硫酸亚铁为原料，合成无机高分子絮凝剂聚合硫酸铁；②、以水玻璃制出活化聚硅酸高聚物；③、聚合硫酸铁与活化聚硅酸复合制得新型高分子复合絮凝剂PFSiS。研究结果表明：SiO2（％）为1.4～2.0％，Fe／Si摩尔比为0.8～1.2，PFSiS的pH值为1.5～1.8，硅酸活化时间在l～18h，可获得絮凝性能优异且稳定性较好的絮凝剂。制备的PFSiS，因不含Al3+等环境污染物、原料为工业副产物，所以具有以下优点：①、安全无害、无二次污染；②、高效低耗，可部分取代价格昂贵的有机合成高分子絮凝剂且无毒性；③、成本低廉，附加值高。在絮凝作用机理研究方面，利用微电泳技术等，探索了PFSiS絮凝作用机理，揭示了起絮凝作用的优势形态，为絮凝剂的研制开发提供了依据。通过研究PFS、聚合硅酸(PSi)及PFSiS的pH变化规律发现：在制备初期，PFSiS并未达到化学平衡状态，而是存在一个相互作用、自行调整聚合的过程，表现在其pH值存在一个变化过程。本研究还利用紫外-可见光谱探索了聚铁基复合絮凝剂的作用机理。紫外-可见吸收光谱研究显示：在200～1000nm的波长范围，PSi无明显吸收。在200～400nm的波长范围，PFSiS和PFS有清晰的吸收光谱，但各自的光谱特征差异较大。在酸性环境中，随着pH值升高，差异越明显，这说明，当pH值偏高时，PFSiS中各成分的反应活性更强，PFS与PSi更容易发生化学反应而形成新的聚合物形态。通过紫外-可见光谱研究以及PFS、PFSiS与PSi的pH值随时间的动态变化规律研究表明： PFSiS 不是PFS、<WP=5>PSi的简单混合，是复合。在PFSiS中，硅与铁发生了不同程度的相互作用，使各自的形态发生了不同的变化。这种作用又与溶液的pH值有关。在不同pH值条件下，铁与硅相互作用程度不同。本文还研究了PFSiS中硅的形态分布与转化规律。通过Si-Mo逐时络合比色法研究表明：pH值较低(如pH为0.64)时，陈化一定时间后，在PFSiS中的PSi主要是高聚体或凝胶态(Sic)；pH值较高(如pH为1.46和1.70)时，陈化一定时间后，PFSiS中的PSi中聚体(Sib)含量比较低pH值时要高。通过絮凝性能研究得出：PFSiS在pH值为1.46和1.70时絮凝效果比低pH值时更好，由此证明，PFSiS中，PSi的优势絮凝形态为中聚体(Sib)。Zeta电位测定研究表明：PFSiS的电荷特性受SiO2含量、Fe／Si摩尔比及酸度等因素影响。对PFSiS的絮凝作用机理研究表明：PFSiS的电中和作用不显著，其絮凝作用机理，表现出较明显的吸附架桥和网捕卷扫特征。通过PFSiS与PFS、PAC处理中药制药废水等的对比试验表明：PFSiS的絮凝效能最佳，对水中CODCr去除率最高，且对水质适应性较好。本研究中，制备PFS-CSM的主要研究内容如下：①、用钛白生产废渣七水硫酸亚铁为原料，合成无机高分子絮凝剂聚合硫酸铁。②、用少量有机胺和卤代烷合成有机阳离子絮凝剂CF，再利用CF对淀粉进行改性，制得阳离子改性淀粉CSM。 ③、用自制聚铁与阳离子改性淀粉合成聚铁基淀粉改性无机/有机复合絮凝剂（PFS-CSM）。通过正交对比实验等，确定了制备复合絮凝剂PFS-CSM的最佳工艺条件：有机胺与卤代烷摩尔比为1:1，反应温度为45℃，反应时间为1h，合成阳离子絮凝剂CF。淀粉预胶化过程中控制淀粉投加浓度为10%，NaOH固体加量为淀粉干基的5%，预胶化温度为65℃～75℃左右，预胶化时间为2h。阳离子絮凝剂CF与改性淀粉有效质量比为1.5:1，活化时间为30s，接枝温度恒定在50℃～60℃，接枝时间为2h左右。聚铁与阳离子改性淀粉的投料比(质量比)为3:1，反应温度为60℃，反应时间为3h。研究的PFS-CSM，具备以下优点：①、不含Al3+；②、成本低廉；③、通过无机/有机复合，可望发展出新的高效集成化混凝处理技术。由絮凝试验及显微照像技术得出：PFS-CSM絮凝过程主要表现为吸附架桥和网捕卷扫的典型特征。PFS-CSM的最佳絮凝pH范围为7.0～9.0，最佳絮凝形态是产生Fe(OH)4-后在此基础上进一步聚合成带正电的铁基高聚物。综合分析表明，其优异的絮凝性能是由其特殊的分子结构决定的，是电性中和与吸附架桥、网捕卷扫协同作用的结果。通过复合絮凝剂PFS-CMS对重庆啤酒集团第二分厂啤酒生产废水等絮凝效果试验得出，该絮凝剂在絮凝效果上优于常用的几种水处理絮凝剂，产生的絮体粗<WP=6>更多还原

【Abstract】 The method of flocculation is the one of the most important technology controlling water pollution. Flocculants are the critical part and the core basis of the technology.At present,flocculants based on salt aluminium are chiefly used abroad and at home. Because the flocculant based on the aluminium salt is low efficiency and exists environment problems, in our country and all over the world, the research and application of flocculant are required to be innovated and raised. At present, the trench of development on the research of flocculant are chiefly :the high efficiency, low consumption, safety, no harmlessness and no two-time pollution. The research of iron system flocculate belongs to the forward position of flocculation science. In this paper, the by-product of titanium white manufacture, FeSO4·7H2O, is used as the raw materials to study the preparation of composite flocculant based on polyferric. A lot of explorations and efforts are made to study and apply high efficiency composite flocculant based on the polyferric in this paper.The major contents of research have: the research of inorganic composite flocculant polyferric silicate sulfate (PFSiS) based on the polyferric and cationic starch-modified inorganic-organic composite flocculant(PFS-CSM) based on the polyferric. They all include the research of preparation、flocculating action mechanism、 flocculating effect and water treatment application trial etc.In this paper, the major contents of preparing PFSiS are as follows: Firstly,the waste residue of titanium white manufacture ,FeSO4·7H2O, is served as the raw material to synthesize inorganic high molecular flocculant polyferric sulfate. Secondly, water glass is used to produce the activated poly silicic acid polymer.Finally,polyferric sulfate and activated poly silicic acid are compounded to make the new type of inorganic high molecular composite flocculant PFSiS. The research result is shown that the percentge of SiO2 is between 1.4~2.0%, the mol ratio of iron to silicon is between 0.8~1.2, the pH value of PFSiS is 1.5~1.8, the activated time of silicic acid is between 1~18 hours, the flocculant has excellent flocculation and better stability. PFSiS, that contains no pollutant of environment ,has huge molecular weight and uses the by-product of industry as the raw material, has the following merits: one is safety、no harmlessness、no two-time pollution. The others are that it has high efficiency and low consumption；and it can partly replace the organic synthesis high polymer flocculate<WP=8>that price is expensive and has toxicity. Another is that the cost is very cheap, and the additional value is very high.For the first time, micro-electrophoresis technology is used to explore the flocculating mechanism of PFSiS, reveal the superiority form of flocculating action and provide the science basis for developing the flocculant.The pH change laws of PFS、 PSi and PFSiS are investigated. It is found that the pH value of PFSiS will change with aging time. The results show that there is interaction between PFS and PSi, and the pH value may affect the degree of their interaction. The results also show that their reaction is not in equilibrium when the flocculant is newly prepared. In acid condition, the pH value changes smoothly when the prime pH is 1.46. But when the prime pH value is higher (1.70) or lower (0.64), the pH value of PFSiS shows apparent relaxation change. The results show that the species of PFSiS will change when the prime pH value is higher or lower. Otherwise, the Fe/Si molar ratio can affect the pH relaxation of PFSiS. When Fe/Si is higher, the pH relaxation of PFSiS changes as PFS does; and when Fe/Si is lower, the pH relaxation of PFSiS changes as PSi does.The ultraviole-visible spectrometric determination shows that, polysilicate (PSi) almost has not abvious absorbence in the range of 200～1000nm wavelength; the absorption spectrometric of PFSiS and PFS is different in the range of 200～400nm wavelength. In acid condition, when the pH value rises, because the a更多还原