Department of Civil, Environmental and Geomatic Engineering, University College London, Gower Street, London, WC1E 6BT, UK.
Environ Sci Technol. 2010 Aug 15;44(16):6371-6. doi: 10.1021/es1007627.
The growth, breakage and regrowth of flocs formed by aluminum sulfate (alum) with humic acid (HA) in water at neutral pH was investigated by jar testing with continuous optical monitoring. Various initial dosages of alum and different breakage shears were investigated to compare the floc strengths and to explore the growth of flocs and regrowth of broken flocs. In all cases there was significant irreversibility of floc breakage when no additional coagulant was added. On the other hand, when a small additional dosage of alum was added to the suspension during floc breakage, the size of regrown flocs was higher than that before breakage. The result did not change with the variation of the initial dosage of alum, and the intensity and duration of floc breakage, provided that the additional coagulant was added shortly before the end of the breakage process. It seems that aluminum hydroxide is better able to form flocs, when newly precipitated, rather than after an extended period of high shear.
采用连续光学监测的烧杯试验研究了中性 pH 条件下水中硫酸铝（明矾）与腐殖酸（HA）形成的絮体的生长、破碎和再生长。考察了不同初始明矾剂量和不同破碎剪切力，以比较絮体强度，探讨絮体的生长和破碎絮体的再生长。在所有情况下，当不添加额外的混凝剂时，絮体破碎具有显著的不可逆性。另一方面，当在絮体破碎过程中向悬浮液中添加少量额外的明矾剂量时，再生絮体的粒径大于破碎前的粒径。只要在破碎过程结束前不久添加额外的混凝剂，该结果就不会随初始明矾剂量的变化、絮体破碎的强度和持续时间而改变。似乎新沉淀的氢氧化铝比在高剪切作用下延长一段时间后更能形成絮体。
