• 关键词：粉煤灰  铝铁复合混凝剂  铝铁形态  分形维数  Zeta电位

• 基金项目：湖北省自然科学基金项目（No.2014CFB285）；武汉市科技计划项目（No.2014060101010065）；中央高校基本科研业务费专项资金资助（No.2015-ZH-B1-08）

• 李柏林
• 1. 武汉理工大学资源与环境工程学院, 武汉 430070;2. 矿物资源加工与环境湖北省重点实验室, 武汉 430070

• 梁亚楠
• 1. 武汉理工大学资源与环境工程学院, 武汉 430070;2. 矿物资源加工与环境湖北省重点实验室, 武汉 430070

• 张程琛
• 1. 武汉理工大学资源与环境工程学院, 武汉 430070;2. 矿物资源加工与环境湖北省重点实验室, 武汉 430070

• 姚亚
• 1. 武汉理工大学资源与环境工程学院, 武汉 430070;2. 矿物资源加工与环境湖北省重点实验室, 武汉 430070

• 章文琴
• 1. 武汉理工大学资源与环境工程学院, 武汉 430070;2. 矿物资源加工与环境湖北省重点实验室, 武汉 430070

• 李晔
• 1. 武汉理工大学资源与环境工程学院, 武汉 430070;2. 矿物资源加工与环境湖北省重点实验室, 武汉 430070

• 摘要：化学混凝法是城市污水处理深度除磷的有效方法，目前常用混凝剂主要存在成本高、除磷效率低且用量大等缺点。本研究采用常压酸浸法，以低成本的铝土矿和粉煤灰为主要原料制备无机复合混凝剂，并对其进行除磷应用及机理研究，结果表明：①自制混凝剂对生活污水中TP去除率达99.58%，出水TP含量为0.012 mg·L^-1，优于GB18918-2002一级A标准。② X-射线衍射和红外光谱结果显示，混凝剂中的Fe-OH、Al-OH、H-OH等基团能与水中的磷酸根作用生成沉淀达到除磷目的，该沉淀在沉降过程中还能吸附不易沉淀的含磷悬浮物，发挥网捕卷扫作用。③采用Ferron逐时络合比色法分析铝铁形态结果显示，混凝剂含有64.14%低聚态铝铁，能中和水中胶体的表面电荷致使胶体脱稳；11.27%中聚态铝铁可吸附在胶体表面，降低其表面电荷，同时以较高的分子量发挥吸附架桥作用；24.59%高聚态铝铁在沉淀过程中可包夹部分胶体粒子，以较大表面积发挥卷扫作用。④分形维数研究结果显示，絮体分形维数在1.2~2.8之间，分形特征较好，能有效发挥絮体的吸附架桥作用。⑤Zeta电位分析结果显示，混凝剂本身带正电荷，能与水中带负电荷的胶体物质发生中和，从而压缩双电子层，使胶体粒子脱稳而从水中去除。混凝剂除磷过程是压缩双电层、电中和、吸附架桥和网捕卷扫多种机制共同作用的动态变化过程。

• Abstract：Chemical flocculation has been widely applied in wastewater treatment to remove phosphorus. Currently, common flocculant mainly has some disadvantages of high cost, low efficiency and large dosage. In this study, inorganic composite flocculants were prepared by using low-cost monohydrallite and coal ash via constant-pressured acid leaching. The phosphorus removal performance and flocculation mechanism of the as-prepared flocculant were discussed. 1 The removal efficiency of TP in the sewage was 99.58%, and the residue TP was 0.012 mg·L^-1, which meets the class A criteria specified in GB 18918-2002. 2 The X-ray diffraction and infrared spectrum reveal that phosphate could be removed by precipitating with perssad like Fe-OH, Al-OH and H-OH. Meanwhile, the precipitation also adsorbed some non-setting phosphorus suspended solids acting aggregation agent. 3 Ferron-complexation timed spectrophotometric method was employed to analyze the chemical form of aluminum and iron. It showed that there was 64.14% low-polymer of Al(Ⅲ) and Fe(Ⅲ), which could neutralize some electric charge of colloidal particles in water and thus cause colloidal particles to precipitate; there was 11.27% mid-polymer of Al(Ⅲ) and Fe(Ⅲ) adsorbed on the surface of colloids, reducing its surface charge and producing adsorption bridging effect with high molecular weight; there was 24.59% high-polymer of Al(Ⅲ) and Fe(Ⅲ) wrapped into partial colloidal particles in the precipitation process, playing aggregation function due to their large surface area. 4 The fractal dimension experiment results show that the fractal dimension of flocculants varied from 1.2 to 2.8, which can play adsorption bridging effectively. 5 The Zeta potential data show that flocculant have positive charge and could react with negative charged colloid material in water. And then, it destabilized colloid particles by compressing electric double layer and removed them from the water. The phosphorus was effectively removed from the water based on the synergistic effect of compressed double electric layer, electric neutralization, adsorption bridging and volume aggregation function.

• Key words：coal ash  Al-Fe compound flocculant  aluminum and iron form  fractal dimension  Zeta potential

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