Chen Changtao, Zhang Tao, Lv Li, Chen Yanxiao, Tang Wenxiang, Tang Shengwei
Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, Chengdu, 610065, China.
Sichuan Base of International Science and Technology Cooperation for Green Chemical Industry, School of Chemical Engineering, Sichuan University, Chengdu, 610065, China.
Water Res. 2021 Jul 1;199:117161. doi: 10.1016/j.watres.2021.117161. Epub 2021 Apr 17.
The disposal and resource utilization of waste activated sludge (WAS) is a big challenge for its high moisture content. Ionic liquid (IL), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM][OTf]), was innovatively used as a conditioner to improve the dewatering performance of WAS. The WAS was characterized by flocs size, three-dimensional excitation-emission matrix (3D-EEM), zeta potential, Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM) for the investigation of intensification mechanism. The results showed that the dewatering performance of WAS conditioned by [EMIM][OTf] was significantly improved. The moisture content was successfully decreased to 64.99±0.92 %, and the intensification mechanism was investigated. The results showed that the structures of extracellular polymeric substance (EPS) were destroyed by [EMIM][OTf]. It brought a sharp decrease of the contents of polysaccharides (PS), proteins (PN), humic acid (HA) and fulvic acid (FA) in tightly bound extracellular polymeric substance (TB-EPS) structure. The inactivation of microbial cells promoted the disintegration of flocs. Large flocs were converted into unstable small particles and biopolymers. In addition, the negative charges of WAS were also neutralized for dissolution of biopolymers in [EMIM][OTf], and the electrostatic repulsion between flocs was weakened. [EMIM][OTf] was easily recycled five times. The research results indicate that specific IL, such as [EMIM][OTf], is a potential conditioner to improve the dewatering performance of WAS.
废弃活性污泥（WAS）因其高含水量，其处置和资源利用是一项重大挑战。创新性地使用离子液体（IL）1-乙基-3-甲基咪唑三氟甲磺酸盐（[EMIM][OTf]）作为调理剂来改善WAS的脱水性能。通过絮体尺寸、三维激发-发射矩阵（3D-EEM）、zeta电位、傅里叶变换红外光谱（FT-IR）和扫描电子显微镜（SEM）对WAS进行表征，以研究强化机理。结果表明，用[EMIM][OTf]调理的WAS脱水性能显著提高。含水量成功降至64.99±0.92%，并对强化机理进行了研究。结果表明，[EMIM][OTf]破坏了胞外聚合物（EPS）的结构。它使紧密结合的胞外聚合物（TB-EPS）结构中的多糖（PS）、蛋白质（PN）、腐殖酸（HA）和富里酸（FA）含量急剧下降。微生物细胞的失活促进了絮体的解体。大絮体转化为不稳定的小颗粒和生物聚合物。此外，WAS的负电荷也被中和，使生物聚合物溶解在[EMIM][OTf]中，絮体之间的静电排斥减弱。[EMIM][OTf]易于循环使用五次。研究结果表明，特定的离子液体，如[EMIM][OTf]，是提高WAS脱水性能的潜在调理剂。
