摘要：本论文研究的是粉煤灰微珠的表面优化及其对液相中磷及铬元素的吸附行为。表面优化过程由重构结构表面和zeta电位优化组成。吸附实验在单一溶质体系和竞争吸附体系中进行。整体和分段吸附过程是通过常见的吸附动力学方程和扩散动力学方程来分析的，吸附等温线是由Langmuir，Freundlich和竞争性Langmuir等温方程来分析的。结果表明：在颗粒表面上沉积的无定形二氧化硅-氧化铝凝胶（有效地扩大MFP的微观表面积）和表面zeta电位通过表面改性吸附阴离子。在吸附实验中，铬更容易被MFP吸附。表面zeta电位和竞争性离子的存在应被认为是影响吸附效率的两个重要因素，较高的温度也可以提高吸附效率。分段动力学分析表明，吸附过程由初期（由准一级动力学方程拟合）和后期（由准二级动力学方程拟合）组成。在较高温度系统和竞争吸附体系下，早期吸附过程的时间跨度将缩短。单一吸附体系的扩散动力学分析表明：吸附过程有三个主要扩散阶段：外部扩散模型控制阶段，内部扩散模型控制阶段和最后阶段。在竞争吸附体系中，磷和铬的吸附过程较早进入第二阶段，而磷的吸附过程只出现在一个吸附阶段。Langmuir吸附等温线方程可以更好地模拟MFP上的磷和铬在单吸附系统中的吸附过程，但是只有铬吸附可以通过竞争性的Langmuir吸附等温线来拟合。

关键词：表面改性；球形颗粒；吸附；磷酸盐；铬

Abstract：The work focuses on surface modification of fly ash spheroidal particle and its application in phosphorus and chromium adsorption process. The surfaces modification process is composed from structural surface reconstitution and zeta potential optimization. The adsorption experiments were carried out in single and competitive solute systems. The whole and piecewise adsorption process was analyzed by common adsorption kinetics equations and diffusion kinetics equations. The adsorption isotherms were analyzed by Langmuir, Freundlich and competitive Langmuir isotherm equations. The results show that: through surface modification, amorphous silica-alumina gels precipitated on the particle surface (by which the micro surface area of MFP effective enlarged) and the surface zeta potential was transmitted to adsorb anions. During adsorption experiment, the chromium was more easily to be adsorbed by MFP. Surface zeta potential and existing of competitive ions should be recognized as two important factors effecting adsorption efficiency. The higher temperature could improve the adsorption efficiency. Piecewise kinetics analysis suggested that the adsorption process is composed of early-stage (fitted by pseudo first-order model) to later-stage (fitted by pseudo second-order model). The time span of early-stage adsorption process would be shortened under higher temperature system and competitive solute systems. Diffusion kinetics analysis of single adsorption system indicated that: the adsorption process consist of three main diffusion stages (external diffusion model control stages, internal diffusion model control stages and finally  stages). In competitive solute system, the adsorption process of phosphorus  and  chromium is earlier to come into second stage and adsorption process of phosphorus appeared only one adsorption stage. Langmuir adsorption isotherm equation can better  simulate  the adsorption process of phosphorus and chromium on MFP in single adsorption system, but only chromium adsorption process could be fitted by competitive Langmuir adsorption isotherm.

Key words: Surface modification；Spheroidal particle；Adsorption；Phosphate； Chromium

目录

第一章绪论 1

1.1铬元素的危害 1

1.2铬元素的去除方法