选择牛血清蛋白和腐殖酸作为实验对象，考察了硫酸铝投加量和pH对两种有机体系有机物去除率、电荷性质以及絮体性质（粒径分布、分形维数和沉降性）的影响。实验结果发现，硫酸铝混凝对腐殖酸的去除效率要高于BSA，当硫酸铝投加量为5 mmol·L－1时，两种体系中DOC的去除率均达到最高。电中和在腐殖酸的混凝去除过程中占主导地位，而吸附架桥是BSA去除的主要机理。对于两种有机体系，随着硫酸铝投加量的升高，絮体粒径逐渐减小，而分形维数增大。相比腐殖酸体系，BSA混凝形成絮体粒径大但分形维数更小，同时絮体沉降性较差。此外，两种体系中DOC去除率在pH值等于6时均达到最高。同时，当pH值从5上升到9的过程中，BSA体系粒径逐渐增加；而在腐殖酸体系中，在pH值小于6时，絮体成长平衡时间延长，同时平衡后絮体粒径要明显大于pH值大于7条件下形成的絮体。
Organic composition is one of most important factors affecting coagulation process. In this study, bovine serum albumin ( BSA) and humic acid were selected as model organic compounds, and the effects of aluminum sulfate dosage and pH on organic removal, charge property and floc properties ( floc size, fractal dimension and settleability) in two organic systems were investigated. It was found that the aluminum sulfate coagulation exhibited better performance in removing humic acid in comparison to BSA. DOC removal reached the maximum for both systems when the dosage of aluminum sulfate was 5 mmol·L-1 . Charge neutralization and adsorption?bridging were major mechanisms for humic acid and BSA removal respectively. For both organic systems, floc size increased while fractal dimension decreased with aluminum sulfate dosage. Compared to humic acid, the floc obtained in BSA coagulation was characterized by larger size, low fractal dimension and poor settleability. The pH 6 was the optimal value for DOC removal for both organic systems. In addition, floc from BSA coagulation became larger with increase in pH from 5 to 9. For humic system, the floc growth period at pH < 6 was greatly extended, and the size of floc coagulated at pH < 6 was lager than that at pH >7.
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