College of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China.
College of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, Gansu 730050, China; College of Resources & Environment, Jiujiang University, Jiujiang, Jiangxi 332005, China.
Water Sci Technol. 2024 Jul;90(1):287-302. doi: 10.2166/wst.2024.225. Epub 2024 Jul 2.
Extracellular polymeric substances (EPS) are a critical influencing factor in sludge dewatering. Disrupting such EPS contributes to the release of bound water in sludge, enhancing the sludge dewatering performance. In This study, quaternized straw fibers that are destructive to the EPS structure and components in active sludge were prepared useing heterogeneous free radical graft polymerization. Straw fibers, dimethyl diallyl ammonium chloride (DMDAAC), ammonium persulfate (APS), and acrylamide (AM) were taken as the substrate, grafting monomer, catalyst, and cross-linking agent, respectively.The optimal processing conditions determined for the DMDAAC-based quaternization and graft modification of straw fibers were as follows: reaction temperature of 60 °C, reaction time of 5 h, 0.100 g of catalyst APS dosage per gram of straw, and 3.000 ml of DMDAAC dosage per gram of straw. The optimal processing conditions yielded 1.335 g of modified straw fibers per gram of straw, 33.67% grafting rate, and 31.70% substitution of the quaternary ammonium groups. The capillary suction time (CST) was conditioned from 243.3 ± 22.6 s in the original sludge to 134.5 ± 34.45 s. The specific resistance to filtration (SRF) was reduced from 8.82 ± 0.51 × 10 m/kg in the original sludge to 4.59 ± 0.23 × 10 m/kg.
胞外聚合物（EPS）是影响污泥脱水的关键因素。破坏这些 EPS 有助于释放污泥中结合水，提高污泥脱水性能。在本研究中，使用非均相自由基接枝聚合制备了破坏活性污泥中 EPS 结构和组成的季铵化秸秆纤维。秸秆纤维、二甲基二烯丙基氯化铵（DMDAAC）、过硫酸铵（APS）和丙烯酰胺（AM）分别作为基质、接枝单体、催化剂和交联剂。确定了 DMDAAC 基秸秆纤维季铵化和接枝改性的最佳工艺条件为：反应温度 60°C，反应时间 5 h，催化剂 APS 用量为每克秸秆 0.100 g，DMDAAC 用量为每克秸秆 3.000 ml。最佳工艺条件下，每克秸秆可得到 1.335 g 改性秸秆纤维，接枝率为 33.67%，季铵基团取代度为 31.70%。原污泥的毛细吸水时间（CST）从 243.3±22.6 s 降至 134.5±34.45 s，比阻从原污泥的 8.82±0.51×10 m/kg 降至 4.59±0.23×10 m/kg。
