摘要
通过对以腐植酸为代表的天然有机物和以高岭土为代表的无机悬浮颗粒的混凝实验,分析对比了天然有机物和无机悬浮颗粒的混凝特性.研究结果表明,腐植酸的最佳pH在5～6之间,而高岭土的最佳pH值在7～8之间.在pH=5.0条件下,腐植酸的高去除率在等电点附近,说明吸附电中和是腐植酸混凝的主要作用机理,而高岭土的高去除率是中性条件下氢氧化铝网扫絮凝的结果.通过PDA对混凝过程进行在线监测,腐植酸的混凝经历了稳定、脱稳、复稳、网扫絮凝四个阶段,而高岭土只经历了脱稳和网扫絮凝两个阶段.显微摄影和图像分析结果表明,腐植酸絮凝体的分形维数随粒径增大而渐小,而高岭土絮凝体的分形维数随粒径增大而增加.
Jar tests were conducted for the coagulation of humic acids （HA） as representational natural organic matters and kaoline as representational inorganic suspended particles. The results showed that the optimum pH value of HA is 5～6, while the optimum pH value of kaoline is 7～8. At pH 5, the best removal of HA corresponds to nearly zero zeta potential so that adsorption and charge-neutralization is the main mechanism of coagulation, while at pH 7 the best removal of kaoline is the result of sweep flocculation of aluminum hydroxide. By means of a photometric dispersion analyzer（PDA）, online monitoring of the Al-humic coagulation process was realized. It is revealed that the coagulation process of HA experiences four stages of stabilization, destabilization, restabilization and sweep coagulation, while the one of kaoline only two stages of destabilization and sweep coagulation. It was also found that in the Al-humic floc growth process, the fractal dimension decreased gradually with the increase of floc size and finally to an equilibrium value. On the contrary, in the Al-kaoline floc growth process, the mean diameter and fractal dimension increase with the agitation time, and finally reach a steady state.
出处
《西安建筑科技大学学报（自然科学版）》
CSCD
北大核心
2005年第3期307-310,321,共5页
Journal of Xi'an University of Architecture & Technology(Natural Science Edition)
基金
国家自然科学基金项目(50278076)
陕西省自然科学基金项目(2002E215)
关键词
天然有机物
无机悬浮颗粒
混凝过程
絮凝体
natural organic matters
inorganic suspended particles
coagulation process
floc
