Chen Jie, Xu Xiaojun, Nie Rui, Feng Li, Li Xuhao, Liu Bingzhi
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China.
School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou 510006, China.
Polymers (Basel). 2020 Nov 18;12(11):2738. doi: 10.3390/polym12112738.
In the present study, a novel graft modified flocculant CTS-g-PAMD was synthesized and applied to conduct sludge conditioning and dewatering. CTS-g-PAMD was copolymerized with AM, DMC and chitosan (CTS) under UV-HO initiation. In addition, the effects of single factor experiments on the molecular weight (MW) CTS grafting efficiency (GE) of CTS-g-PAMD were determined and the optimal copolymerization conditions were achieved. The GE of CTS-g-PAMD reached 91.1% and the MW was 4.82 × 10 Da. As revealed from the characterized results of Fourier-transform infrared spectra (FT-IR), H/ NMR, X-ray diffraction (XRD), scanning electron microscopic (SEM) and X-ray photoelectron spectroscopy (XPS), the successful synthesis of CTS-g-PAMD was confirmed, which is considered to be conducive to explaining sludge dewatering performance. Under the optimal conditions (pH = 7.0, flocculant dosage = 35 mg/L), the best flocculating performance (FCMC: 73.7%; SRF: 4.7 × 10 m·kg, turbidity: 9.4 NTU) and large and dense sludge flocs (floc size d = 379.142 µm, floc fractal dimension D = 1.58) were formed. The DMC and CTS chain segments exhibiting cationic properties significantly improved the positive charge density and enhanced the electrical patching effect of CTS-g-PAMD. The long molecular chain of CTS-g-PAMD exhibited superior extensibility, which enhanced bridging effect on adsorption. Moreover, the sludge floc after undergoing CTS-g-PAMD conditioning exhibited robust shear resistance and regeneration ability. After the sludge floc was crushed and broken, a large and dense sludge floc was formed, helping significantly reduce the sludge specific resistance (SRF), turbidity and cake moisture content (FCMC) and enhance the sludge dewatering effect. The novel CTS-g-PAMD flocculant shows promising practical applications and high market value.
在本研究中，合成了一种新型接枝改性絮凝剂CTS-g-PAMD，并将其应用于污泥调理和脱水。CTS-g-PAMD在紫外光-H₂O₂引发下与丙烯酰胺（AM）、二甲基二烯丙基氯化铵（DMC）和壳聚糖（CTS）共聚。此外，通过单因素实验确定了CTS-g-PAMD的分子量（MW）和CTS接枝效率（GE）的影响，并获得了最佳共聚条件。CTS-g-PAMD的接枝效率达到91.1%，分子量为4.82×10⁶Da。傅里叶变换红外光谱（FT-IR）、¹H NMR、X射线衍射（XRD）、扫描电子显微镜（SEM）和X射线光电子能谱（XPS）的表征结果证实了CTS-g-PAMD的成功合成，这被认为有助于解释污泥脱水性能。在最佳条件（pH = 7.0，絮凝剂用量 = 35 mg/L）下，形成了最佳絮凝性能（自由水含量：73.7%；比阻：4.7×10¹²m/kg，浊度：9.4 NTU）以及大而密实的污泥絮体（絮体尺寸d = 379.142 µm，絮体分形维数D = 1.58）。表现出阳离子性质的DMC和CTS链段显著提高了正电荷密度，增强了CTS-g-PAMD的电补丁效应。CTS-g-PAMD的长分子链表现出优异的伸展性，增强了吸附的桥连效应。此外，经过CTS-g-PAMD调理后的污泥絮体表现出强大的抗剪切性和再生能力。污泥絮体被破碎后，形成了大而密实的污泥絮体，有助于显著降低污泥比阻（SRF）、浊度和滤饼含水率（自由水含量），并增强污泥脱水效果。新型CTS-g-PAMD絮凝剂显示出良好的实际应用前景和较高的市场价值。
