State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China; Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing 400044, China; Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
Ultrason Sonochem. 2018 Jun;44:53-63. doi: 10.1016/j.ultsonch.2018.02.017. Epub 2018 Feb 7.
In this study, the ultrasonic (US)-initiated template copolymerization was employed to synthesize a novel cationic polyacrylamide (CPAM) characterized by a microblock structure using dimethyldiallylammonium chloride (DMDAAC) and acrylamide (AM) as monomers, and sodium polyacrylate (NaPAA) as template. The polymers structure property was analyzed by Fourier transform infrared spectroscopy (FT-IR), H nuclear magnetic resonance spectroscopy (H NMR) and thermogravimetric analysis (TGA). The results showed that a novel cationic microblock structure was successfully synthesized in the template copolymer of DMDAAC and AM (TPADM). Meanwhile, the analysis result of association constant (M) provided powerful support for a I Zip-up (ZIP) template polymerization mechanism and the formation of the microblock structure. The factors affecting the polymerization were investigated, including ultrasonic power, ultrasonic time, monomer concentration, initiator concentration, m:m and n:n. The sludge dewatering performance of the polymers was evaluated in terms of specific resistance to filtration (SRF), filter cake moisture content (FCMC), floc size (d) and fractal dimension (D). Flocculation mechanism was also analyzed and discussed. The sludge dewatering results revealed that the polymer with the novel microblock structure showed a more excellent flocculation performance than those with randomly distributed cationic units. A desirable flocculation performance with a SRF of 4.5 × 10 m kg, FCMC of 73.1%, d of 439.156 µm and D of 1.490 were obtained at pH of 7.0, dosage of 40 mg L and the molecular weight of 5.0 × 10 Da. The cationic microblock extremely enhanced the polymer charge neutralization and bridging ability, thus obtaining the excellent sludge dewatering performance.
在这项研究中，采用超声引发模板共聚的方法，以二甲基二烯丙基氯化铵（DMDAAC）和丙烯酰胺（AM）为单体，以聚丙烯酸钠（NaPAA）为模板，合成了一种具有微嵌段结构的新型阳离子聚丙烯酰胺（CPAM）。通过傅里叶变换红外光谱（FT-IR）、氢核磁共振光谱（H NMR）和热重分析（TGA）对聚合物的结构性能进行了分析。结果表明，成功地在 DMDAAC 和 AM 的模板共聚物（TPADM）中合成了一种新型阳离子微嵌段结构。同时，缔合常数（M）的分析结果为 Zip-up（ZIP）模板聚合机理和微嵌段结构的形成提供了有力支持。考察了超声功率、超声时间、单体浓度、引发剂浓度、m：m 和 n：n 等因素对聚合反应的影响。采用比阻抗过滤（SRF）、滤饼水分含量（FCMC）、絮体尺寸（d）和分形维数（D）评价了聚合物的污泥脱水性能。还分析和讨论了絮凝机理。污泥脱水结果表明，具有新型微嵌段结构的聚合物具有比带有随机分布阳离子单元的聚合物更优异的絮凝性能。在 pH 值为 7.0、用量为 40 mg/L、分子量为 5.0×106 Da 的条件下，可获得理想的絮凝性能，SRF 为 4.5×1010 m/kg，FCMC 为 73.1%，d 为 439.156 µm，D 为 1.490。阳离子微嵌段极大地增强了聚合物的电荷中和和桥联能力，从而获得了优异的污泥脱水性能。
