Effect of Hydrophilic Comonomer and Surfactant Type on the Colloidal Stability and Size Distribution of Carboxyl- and Amino-Functionalized Polystyrene Particles Prepared by Miniemulsion Polymerization

Langmuir ◽  
2007 ◽  
Vol 23 (10) ◽  
pp. 5367-5376 ◽  
Author(s):  
Anna Musyanovych ◽  
Renate Rossmanith ◽  
Christian Tontsch ◽  
Katharina Landfester
Keyword(s):  
Size Distribution ◽  
Colloidal Stability ◽  
Miniemulsion Polymerization

scholarly journals Size Distribution and Phosphate Removal Capacity of Nano Zero-Valent Iron (nZVI): Influence of pH and Ionic Strength

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2939
Author(s):  
Dantong Lin ◽  
Liming Hu ◽  
Irene M. C. Lo ◽  
Zhigang Yu
Keyword(s):  
Ionic Strength ◽  
Size Distribution ◽  
Environmental Conditions ◽  
Colloidal Stability ◽  
Removal Rate ◽  
Phosphate Removal ◽  
Zero Valent Iron ◽  
Removal Capacity ◽  
Nano Zero Valent Iron ◽  
Ph Conditions

Nano zero-valent iron (nZVI) has been considered as a promising material for groundwater remediation in the past few decades. The size distribution of nZVI is one of the main factors that influences its transport capability and remediation capacity. However, studies on the size distribution of nZVI under different environmental conditions are still limited. In this study, the influence of the pH (pH = 5, 7, 9) and ionic strength (IS = 0, 15, 30, 45 mM) on the size distribution of nZVI are investigated. The dynamic light scattering (DLS) method is used to study the variation of the size distribution of nZVI aggregate with time, and batch tests are performed to evaluate the efficiency of phosphate removal. Meanwhile, the phosphate removal capacity of nZVI with different size distribution was examined. Experimental results show that under low IS and high pH conditions, nZVI aggregate exhibited a stable, narrow and one-peak size distribution. By contrast, under high IS and low pH conditions, nZVI exhibited a wide and complicated size distribution with multiple peak values. This different pattern in size distribution was further explained by the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory. The phosphate removal rate of nZVI under acidic and neutral conditions is higher than 98% but is only 68% under alkaline conditions. The phosphate removal capacity is insensitive to the variation of IS since the removal rate is higher than 97% for different IS conditions. Favorable environmental conditions for colloidal stability and removal capacity of nZVI can be different, which needs comprehensive consideration in the application.

Reversible Addition–Fragmentation Chain Transfer (RAFT) Polymerization in Miniemulsion Based on In Situ Surfactant Generation

2011 ◽  
Vol 64 (8) ◽  
pp. 1033 ◽  
Author(s):  
S. R. Simon Ting ◽  
Eun Hee Min ◽  
Per B. Zetterlund
Keyword(s):  
Potassium Hydroxide ◽  
Colloidal Stability ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Miniemulsion Polymerization ◽  
High Energy ◽  
Reversible Addition ◽  
Raft Agent ◽  
Surface Active

Reversible addition–fragmentation chain transfer (RAFT) polymerization of styrene has been implemented in aqueous miniemulsion based on the in situ surfactant generation approach using oleic acid and potassium hydroxide in the absence of high energy mixing. The best results were obtained using the RAFT agent 3-benzylsulfanyl thiocarbonyl sufanylpropionic acid (BSPAC), most likely as a result of the presence of a carboxylic acid functionality in the RAFT agent that renders it surface active and thus imparts increased colloidal stability. Stable final miniemulsions were obtained with no coagulum with particle diameters less than 200 nm. The results demonstrate that the RAFT miniemulsion polymerization of styrene employing the low energy in situ surfactant method is challenging, but that a system that proceeds predominantly by a miniemulsion mechanism can be achieved under carefully selected conditions.

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