【作者】 胡承志；

【导师】 张广军； 曲久辉；

【作者基本信息】 西北农林科技大学 ， 环境科学， 2003， 硕士

【摘要】 电解法制备聚合铝的提出，开创了一条新的聚合铝生产途径，符合国内外的研究方向和发展趋势。电解法制备的聚合铝不仅具有高Al₁₃含量的优点，而且这种方法还有适于现场生产和批量制备的特点，因此具有重要的实用价值和广阔的应用前景。本研究的主要目的是为以电解法制备纳米级絮凝剂的研究开发与生产应用奠定理论与技术基础。 为进一步优化电解参数，提高电解PAC的品质，给研究提供理想的样品，在实验室条件下制备了一批具有不同碱化度和铝浓度的PAC，在此过程中对电解液的理化特征参数进行在线监测，发现随电解时间的延长，总铝含量逐渐升高；温度、pH值、碱化度均是先逐渐升高，随后到达一稳定值；根据碱化度的变化，可将电解液中铝形态的变化过程分为三个阶段。 采用Al-Ferron逐时络合比色法，²⁷Al NMR核磁共振法，并借助扫描电镜，对确定条件下电解PAC的形态分布、聚合结构、结晶形貌等形态结构特征进行了深入研究。结果表明：电解PAC中的大部分铝以Al₁₃或多个Al₁₃的聚集形态存在；制备过程中分别将总铝与碱化度控制在1mol/L与2.3左右，便可得到Al_b含量大于65％的PAC，与其它方法相比，电解法可制备出品质优良的PAC。采用Al-Ferron络合比色法测定的PAC中Al_b含量与²⁷Al NMR所测定的Al₁₃含量具有高度一致性，故在实际分析中，可用Al_b含量代表Al₁₃含量。 以Al-Ferron络合比色法为基本方法着重对电解PAC中Al_b形态的稳定性进行了研究，发现Al_b含量可在一个月之内基本保持稳定，在两个月内其含量依然大于原Al_b含量的一半；碱化度和总铝浓度对Al_b的稳定性具有重要影响；电解PAC中Al_b含量与其pH值具有正相关关系。 采用混凝烧杯试验方法，针对模拟水样和实际水样，对电解制备的高Al₁₃含量的PAC的絮凝效能及其作用机制进行了研究。絮凝试验表明：聚合铝的絮凝效能与其铝形态分布有关，Al₁₃含量与其絮凝效能成正比关系，在微碱性及中性条件下，相应的絮凝效能由强到弱次序为Al₁₃＞Al_u＞Al_m；随着pH值的增加，达到等电点所需的絮凝剂投药量逐渐增加，絮凝剂的混凝区域逐渐变宽；絮凝剂的絮凝效能与混凝后水样中的残留铝含量成反比关系；对于生活污水和含油废水，电解PAC的处理效果明显优于普通絮凝剂。更多还原

【Abstract】 A novel method concerning an electrolysis process for preparation of PAC was developed. The PAC contains high content of Al 13 that was considered to be the most effective flocculating component, hi addition, the method is suitable for producing PAC on the spot and a batch production. It has a wide utilizing prospect and an important practical value. This paper aimed at providing basic theory and technique for Electrolysis-PAC’s R&D and practical use.To optimize the quality of Electrolysis-PAC and provide ideal flocculants for next experiments, E-PACs, with different concentration of Al(III) and basicity, were prepared in lab. During the preparation, temperature, pH, and basicity of electrolyte were monitored. The results showed that, these parameters at first increased gradually and then tended towards a steady data with the extension of electrolysis process, and the transforming progress of aluminum species could be set apart three phases according to basicity.The species distribution of hydrolyzed Al(III), aggregation configuration, the characteristics of crystal of E-PAC were characterized by using Al-Ferron time complex colorimetric method, 27 Al NMR spectroscopy, and transmission electron micrograph (TEM). The results illuminated that the predominant aluminum species of E-PAC was Aln (Alb) or small aggregated Aln, and the quality of E-PAC was more outstanding than ordinary PACs. The content of Alb characterized by using Al-Ferron time complex colorimetric method and Al13 characterized by using 27 Al NMR spectroscopy was equivalent on the whole.The stability of Alb in E-PAC was studied. The results showed that the content of Alb could hold the line within a month, and the stability of Alb was significantly affected by concentration of aluminum and basicity. Along with the increase of deposit time there was a positive correlativity between the content of Alb and pH.The coagulation behavior of E-PAC was investigated. The results indicated that coagulation efficiency was enhanced by high content of Aln species because of its characteristics of higher positive charge (+7) and strong binding ability. E-PAC was more effective in removing SS, RT, and oil from water and wastewater than other coagulants. There was a negative correlativity between the content of residual aluminum in finished water and coagulation efficiency.更多还原