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Enhanced sludge dewaterability via ozonation catalyzed by sludge derived biochar loaded with MnFe2O4: Performance and mechanism investigation
Journal of Cleaner Production ( IF 9.7 ) Pub Date : 2021-09-25 , DOI: 10.1016/j.jclepro.2021.129182
Tingting Xiao 1 , Xiaohu Dai 1 , Xiankai Wang 2 , Sisi Chen 1 , Bin Dong 1, 2
Affiliation  

In order to develop an efficient and environmental-friendly alternative for enhancing dewatering performance of waste activated sludge (WAS), the sludge derived biochar loaded with MnFe2O4 (MnFe2O4@SBC) was firstly prepared for catalyzing ozonation of sludge. The optimal condition was determined to be pH = 6, O3 dosage = 60 mg/g VS and MnFe2O4@SBC dosage = 600 mg/g VS, under which the capillary suction time (CST) and specific resistance to filtration (SRF) of WAS declined from 98.3 ± 1.0 s and 1.1 ± 0.03 × 1014 m/kg to 18.3 ± 0.8 s and 0.32 ± 0.03 × 1014 m/kg, respectively. The water content (Wc wt.%) of sludge cake declined from 87.1 ± 0.98% to 68.1 ± 0.87%. The mechanism for enhanced dewatering performance of WAS by MnFe2O4@SBC was systematically clarified. Firstly, the circulation of valence states for Fe and Mn on the surface of MnFe2O4@SBC was found promoting the conversion of O3 into highly active free radicals and the generation of hydroxyl radicals (·OH). Secondly, the density functional theory (DFT) calculation firstly manifested that O3 molecules were easier to be activated and dissociated into ·OH groups on the surface of MnFe2O4 phase. With the above promotion of ·OH generation, the inner part of sludge flocs especially the protein in extra-cellular polymers (ECPS) was destructed strongly, with significant release of bound water and the decrease in water bound energy. The organic biopolymers with negative charges were diminished followed by the increased zeta potential and enlarged particle size, resulting in the enhanced dewatering performance of WAS. This study illustrated the rationality and validity of the new strategy for enhanced sludge dewatering in both practice and theory, shedding light on the further development of sludge dewatering technology.



中文翻译:

负载MnFe2O4的污泥衍生生物炭催化臭氧化增强污泥脱水能力:性能和机理研究

为了开发一种高效、环保的替代方案来提高废弃活性污泥 (WAS) 的脱水性能,首先制备了负载 MnFe 2 O 4 (MnFe 2 O 4 @SBC)的污泥衍生生物炭,用于催化污泥臭氧化。最佳条件确定为 pH = 6,O 3用量 = 60 mg/g VS 和 MnFe 2 O 4 @SBC 用量 = 600 mg/g VS,在此条件下毛细管抽吸时间(CST)和比过滤阻力( WAS 的 SRF) 从 98.3 ± 1.0 s 和 1.1 ± 0.03 × 10 14  m/kg下降到 18.3 ± 0.8 s 和 0.32 ± 0.03 × 10 14 米/公斤,分别。污泥饼的含水量(Wc wt.%)从87.1±0.98%下降到68.1±0.87%。系统阐明了 MnFe 2 O 4 @SBC提高 WAS 脱水性能的机制。首先,发现MnFe 2 O 4 @SBC表面Fe 和Mn 的价态循环促进O 3转化为高活性自由基和羟基自由基(·OH) 的生成。其次,密度泛函理论(DFT)计算首先表明,O 3分子更容易在MnFe 2 O 4表面被活化并解离成·OH基团。阶段。在上述·OH生成的促进下,污泥絮体内部特别是胞外聚合物(ECPS)中的蛋白质被强烈破坏,结合水大量释放,水结合能降低。随着带负电荷的有机生物聚合物减少,zeta 电位增加和粒径增大,WAS 的脱水性能增强。本研究从实践和理论两方面论证了强化污泥脱水新策略的合理性和有效性,为进一步发展污泥脱水技术提供了启示。

更新日期:2021-09-29
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