School of Civil and Transportation Engineering, Guangdong University of Technology, No 100, Waihuan Xi Road, Higher Education Mega Center, Panyu District, Guangzhou, 510006, Guangdong, People's Republic of China.
School of Civil Engineering and Architecture, Chongqing University of Science and Technology, Chongqing, 401331, China.
Environ Sci Pollut Res Int. 2021 Oct;28(37):51865-51878. doi: 10.1007/s11356-021-14325-3. Epub 2021 May 15.
Flocculation is one of the commonly used sludge conditioning methods in water supply plants, which can improve the sludge dewatering performance by reducing the specific resistance of sludge (SRF), decreasing the amount of sludge, and finally lowering the transportation cost and subsequent disposal cost of sludge. Therefore, it is particularly important to develop new and efficient flocculants. In this paper, the template copolymer of acryloxy trimethylammonium chloride (DAC) and acrylamide (AM) was successfully synthesized by microwave-template copolymerization (MV-TP) using sodium polyacrylate (NaPAA) as template. The template copolymer was analyzed by infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance hydrogen spectroscopy (H NMR), and scanning electron microscopy (SEM). It was found that this template copolymer had obvious cationic microblock structure. In addition, the test results of association constant (K) and polymerization kinetics showed that the MW-TP was assigned to free radical initiated polymerization and the polymerization mechanism was I Zip-up (ZIP). It confirmed the formation of cation fragment structure again. Due to its dense positive charges in this new cationic microblock structure, it greatly improved the functions of electric neutralization, electrical patching, and adsorption bridging. The cationic fragment structure in the template copolymer could help to generate large and dense floc structure and form stable drainage channels. Under external pressure, these large and compact floc structures had greater compressive resistance, which avoided deformation and blockage of drainage channels and voids. It was beneficial to reduce SRF and evidently enhanced sludge dewatering performance.
絮凝是给水厂常用的污泥调理方法之一，通过降低污泥比阻 (SRF)、减少污泥量，最终降低污泥运输成本和后续处置成本，可改善污泥脱水性能。因此，开发新型、高效的絮凝剂尤为重要。本文采用微波模板共聚法 (MV-TP) 以聚丙烯酸钠 (NaPAA) 为模板成功合成了季铵盐型丙烯酰氧三甲铵氯化物 (DAC) 和丙烯酰胺 (AM) 的模板共聚物。通过红外光谱 (FT-IR)、X 射线光电子能谱 (XPS)、核磁共振氢谱 (H NMR) 和扫描电子显微镜 (SEM) 对模板共聚物进行了分析。结果表明，该模板共聚物具有明显的阳离子微嵌段结构。此外，通过缔合常数 (K) 和聚合动力学的测试结果，MW-TP 被归为自由基引发聚合，聚合机理为 I Zip-up (ZIP)。这再次证实了阳离子片段结构的形成。由于这种新型阳离子微嵌段结构中带有的密集正电荷，极大地提高了电中和、电修补和吸附架桥的功能。模板共聚物中的阳离子片段结构有助于生成大而密集的絮体结构，并形成稳定的排水通道。在外压作用下，这些大而致密的絮体结构具有更大的抗压能力，避免了排水通道和空隙的变形和堵塞，有利于降低 SRF，显著提高污泥脱水性能。
