Distinct mechanisms of particle aggregation induced by alum and PACl: Floc structure and DLVO evaluation
Distinct mechanisms of particle aggregation induced by alum and PACl: Floc structure and DLVO evaluation
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明矾和 PACl 诱导颗粒聚集的独特机制：絮体结构和 DLVO 评估
DOI：
10.1016/j.colsurfa.2008.12.005
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发表时间：
2009-09
影响因子：
5.2
通讯作者：
Tang, Hongxiao
中科院分区：
文献类型：
--
作者：
Wu, Xiaohong;Ge, Xiaopeng;Wang, Dongsheng;Tang, Hongxiao
用光散射法研究了不同OH/Al比的明矾和聚合氯化铝（PAC 1）对SiO2微球的相互作用。在pH值为6.5、盐浓度为0.01mol/L的条件下，考察了不同混凝剂投加量对混凝效果的影响。根据粒度分布和zeta电位的测量，电荷中和被认为是所有混凝剂的主要混凝步骤，而其他不同的混凝步骤也涉及取决于原位形成或预形成的水解产物。明矾的絮凝作用主要表现为表面覆盖和扫描絮凝作用，而PAC的絮凝作用主要表现为聚阳离子膜和桥状絮凝作用。基于简化的DLVO理论，从相互作用力的角度解释了颗粒聚集现象。结果表明，在较低浓度（1-2μmol/L）下，PAC l的颗粒团聚性能优于明矾，这主要是由于高正性聚阳离子在较长距离下诱导了较大的能垒降低和较深的次级最小值。当次级深度超过12 kT时，次级极小值的作用被发现是显著的。对PAC_（22），尤其是Al_（13）含量较高的PAC_（22），相互作用能的计算结果与混凝结果吻合较好。然而，对于明矾和含有其它铝物质的PAC 1，其它相互作用力胜过电排斥。
Interactions of silica microspheres were examined by light scattering in presence of alum and polyaluminum chloride (PACl) with various OH/Al ratios. The coagulation behaviors were investigated using different coagulant dosages at constant pH (6.5) and salt concentration (0.01mol/L). Based on the measurement of size distribution and zeta potential, charge neutralization was proposed to be the primary coagulation step for all the coagulants while other distinct coagulation steps were also involved depending on in situ formed or preformed hydrolyzing products. Precipitate coverage and sweep flocculation were induced for alum, contrasted to polycation patch and bridge aggregation for PACl. Based on simplified DLVO theory, particle aggregation was explained in terms of interaction forces. It was demonstrated that PACl outperformed alum in particle agglomeration at lower concentration (1–2μmol/L), owing mainly to the considerable energy barrier reduction and deeper secondary minimum at longer distance induced by high positive polycations. The role of secondary minimum was found to be significant when secondary depth exceeded 12kT. The interaction energy calculations coincided well with coagulation result for PACl, especially PACl22 with high content Al13. However, other interaction forces prevailed over the electrical repulsion for alum and PACl containing other aluminum species.
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DOI：
10.1016/0021-9797(90)90331-h
发表时间：
1990-11
期刊：
--
影响因子：
--
作者：
R. Amal;J. Raper;T.David Waite
通讯作者：
R. Amal;J. Raper;T.David Waite
影响因子：
3.9
作者：
A. Marmur
通讯作者：
A. Marmur
影响因子：
--
作者：
Hamaker, HC
通讯作者：
Hamaker, HC
影响因子：
2.2
作者：
Dongsheng Wang;Hong-xiao Tang
通讯作者：
Dongsheng Wang;Hong-xiao Tang
影响因子：
--
作者：
W. Stumm;J. J. Morgan-J.
通讯作者：
W. Stumm;J. J. Morgan-J.